Department of Physiology, Radboud University Medical Center, Nijmegen, Netherlands Rene.Bindels@radboudumc.nl
Mg2+ is of great physiological importance in their function in neural excitability, muscle contraction, bone formation, and hormone secretion. The human body is equipped with an efficient negative feedback system counteracting variations of the Mg2+ balance. Mg2+ balance is maintained predominantly by the kidneys which increase their fractional reabsorption under conditions of deprivation. Rapid progress has recently been made in identification and characterization of the Mg2+ transport proteins contributing to the delicate balance of this cation. Expression cloning approaches in combination with knockout mice models and genetic studies in families with a disturbed Mg2+ balance revealed novel gatekeeper proteins including members of the transient receptor potential (TRP) channels. These epithelial Mg2+ channels (TRPM6 and TRPM7) form prime targets for hormonal control of the active Mg2+ flux from the urine space to the blood compartment. The characteristics of newly identified transporters will be discussed and in particular the distinctive molecular regulation of these new Mg2+ transport proteins in (patho)physiological situations will be highlighted.
Magnesium status evaluation: where are we now and what is the future?
Andrzej Mazur1, Zohara Arshad2, Alzbeta Marcek Chorvatova3, Daniel Bechet1, Edmond Rock1
1 Unité de Nutrition Humaine, Inra, Clermont Université, Clermont-Ferrand, France, 2 post graduate MD, Wroclaw, Poland, 3 Department of Biophotonics, International Laser Center, Bratislava, Slovakia email@example.com
Currently, magnesium intake is considered as sub-optimal in large part of population in Western countries. This supports an increased risk of latent magnesium deficiency within Western diet behaviour. Chronic latent magnesium deficiency may be at origin of a broad range of dysfunctions and the progressively of health deterioration. In particular, numerous association studies suggest the relationship between low magnesium intake, low serum magnesium and cardio-metabolic diseases. In addition, several pathophysiological conditions may contribute to chronic subclinical magnesium deficiency.In comparison to severe and acute magnesium deficiency the diagnosis of chronic latent deficiency is difficult because of nonspecific clinical symptoms and magnesaemia which is often within reference intervals. Current clinical laboratory tests are almost limited to total serum magnesium. Less frequently ionized serum magnesium, total red blood cell magnesium and urinary excretion of magnesium are measured. Recent meta-analyses have shown that both circulating and urine magnesium concentrations respond to oral magnesium supplementation and dietary depletion, confirming their value as markers of magnesium status. However, the assessment of magnesium status to diagnose latent deficiency is problematic because only subtle changes occur in these parameters and there is a large inter-individual variability. Accurate assessment of magnesium status remains a major challenge for the clinical laboratory, since magnesium is mainly an intracellular cation and in the body is mostly found in the bone and soft tissues. Therefore, to develop rapid, robust test representative for intracellular magnesium or for the whole body magnesium in humans is extremely difficult to achieve. The significant progress in various areas offers great opportunities in developing new approaches to the assessment of magnesium status, e.g. use of stable isotopes of magnesium, new dyes for intracellular magnesium or magnesium metabolism related gene expression measurements. This review focuses on current knowledge and future trends in the magnesium status evaluation.
Magnesium deficiency and diseases
Vanderbilt Epidemiology Center, Department of Medicine, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37203,USA. qi.dai@Vanderbilt.Edu
The magnesium deficiency rate in an US population with a high calcium magnesium intake ratio will be presented. Data show that calcium:magnesium intake ratio modifies the associations between intakes of magnesium and calcium and risk of gastrointestinal neoplasia as well as total mortality (i.e. cancer mortality and CVD mortality). Based on the epidemiologic studies conducted in both populations with low or high calcium:magnesium intake ratios, calcium:magnesium ratios between 1.7 and 2.6 may serve as an optimal ratio range for magnesium and calcium to show physiological benefits. In addition, the inverse association between serum vitamin D status and risk of cardiovascular mortality and colorectal cancer mortality only appeared in those with high magnesium intake. Results from an ongoing randomized trial also support the findings from epidemiologic studies. Gene-nutrient interactions will be presented between calcium:magnesium intake ratio and polymorphisms in three genes in relation to risk of colorectal neoplasia.
Daily magnesium fluxes regulate cellular timekeeping and energy balance
Gerben van Ooijen
Royal Society Laboratory, School of Biological Sciences,University of Edinburgh, UK Gerben.vanOoijen@ed.ac.uk
Throughout evolution, life on earth has negotiated natural day/night cycles. Biological rhythms evolved to anticipate this environmental rhythm, and are fundamental to the biology of most eukaryotes. Endogenous circadian clocks coordinate behaviour and physiology to resonate with the environmental cycle of day and night through complex networks of clock-controlled genes. A fundamental knowledge gap exists however, between circadian gene expression cycles and the biochemical mechanisms that ultimately facilitate circadian regulation of cellular metabolism.
In this talk, I will report circadian rhythms in the intracellular concentration of magnesium ions, which act as a cell-autonomous timekeeping component to determine key clock properties in cells from organisms that diverged from each other over a billion years ago: humans and unicellular algae. Given the essential roles of magnesium as a cofactor for NTPs, functional consequence of magnesium oscillations include dynamic regulation of cellular energy expenditure over the daily cycle. The global regulation of nucleotide triphosphate turnover by intracellular availability of magnesium has the potential to impact upon any cellular system where MgNTP hydrolysis might become rate limiting. It will now be important to identify which additional biological processes are subject to this form of regulation in tissues of multicellular organisms such as humans, in the context of health and disease.
Magnesium and cardiovascular biology in health and disease
Rhian M. Touyz
Institute of Cardiovascular and Medical Sciences, University of Glasgow, UK Rhian.Touyz@glasgow.ac.uk
Until recently the (patho)physiological role of magnesium was ignored, due in large part to 1) the paucity of information on how magnesium is regulated and 2) to the lack of specific and sensitive methodologies to accurately measure magnesium. However with the discovery of specific magnesium transporters and improved techniques to assess cellular and plasma magnesium levels, there has been growing interest in the field of magnesium biology and its role in cardiovascular biology and clinical medicine. Experimental evidence indicates that cellular magnesium homeostasis is tightly regulated by multiple novel magnesium transporters including members of the SoLute Carrier family 41 (SLC41A1/A2), Transient Receptor Potential Melastatin 6 and 7 cation channel (TRPM6/7), Magnesium Transporter protein 1 (MagT1) and Ancient Conserved Domain Protein (ACDP) family proteins. Magnesium transport is dynamically regulated. While total Mg2+ levels change acutely in response to various stimuli, intracellular free Mg2+ concentration ([Mg2+]i) remains relatively constant indicating the crucial role of Mg2+ in cellular function. Mg2+ is an important second messenger influencing hundreds of enzymes and signalling molecules. In particular it appears to be the major second messenger in immune cells. Physiologically Mg2+ regulates cell growth, survival, apoptosis, migration, contraction/dilation and secretion and is especially important in the regulation of cardiac and vascular function, in part through its Ca2+ antagonistic actions. Pathologically, perturbations in [Mg2+]i and alterations in magnesium transporters influence cellular inflammation, fibrosis, cytoskeletal disorganisation and immune dysregulation, processes that contribute to cardiovascular injury and disease. Epidemiological and clinical studies have demonstrated an inverse association between plasma Mg2+ levels and blood pressure, and hypomagnesaemia has been reported in diabetes, metabolic syndrome and preeclampsia. Cardiac arrhythmias that are typically associated with hypomagnesaemia include long QT syndrome (Torsades de pointes). The role for magnesium as a therapeutic agent is being tested in numerous large clinical trials. This presentation will present new insights into the molecular biology and transmembrane transport of magnesium and will discuss clinical implications of magnesium in health and disease. The role of magnesium and its transporters in vascular biology and cardiovascular medicine will be highlighted.
Dietary magnesium and cardiovascular diseases
Human Nutrition Unit, Faculty of Medicine and Health Sciences, Biochemistry & Biotechnology Department, Rovira i Virgili University, and Sant Joan de Reus Hospital, IISPV, Reus, Spain firstname.lastname@example.org
Magnesium is an essential mineral for the human body, acting as a coenzyme in different reactions and in the production and transport of energy and proteins. The major food sources of magnesium are fruits, vegetables, legumes, nuts, and whole grains. Some evidence suggests that high magnesium intake plays a protective role not only in cardiovascular risk factors, such as diabetes mellitus, hypertension, and metabolic syndrome, but also in cardiovascular disease and mortality.
A meta-analysis evaluating the association between magnesium and the risk of cardiovascular events demonstrated that both dietary and serum magnesium were inversely related with the risk of total cardiovascular events. Similarly, inverse associations between dietary magnesium intake and risk of stroke or ischemic heart disease were also demonstrated in some studies.
In some but not in all prospective studies, an inverse association between magnesium intake and cardiovascular mortality was observed. An inverse association between dietary or plasma magnesium concentrations and sudden cardiac death was also reported, and serum magnesium has also been inversely associated with cardiovascular, cancer, and all-cause mortality in middle-aged men.
Although some studies have shown that dietary magnesium intake is inversely related to cardiovascular disease and mortality, very few have evaluated the risk of all-cause mortality, and these associations have not been evaluated previously in Mediterranean individuals.
We have evaluated the association between magnesium intake and cardiovascular disease and mortality risk in a Mediterranean population at high cardiovascular risk with high average magnesium intake, using data of the PREDIMED (Prevención con Dieta Mediterránea) study. The PREDIMED study is a randomized clinical trial aiming to assess the effect of Mediterranean diet on the primary prevention of cardiovascular disease. In this context Energy-adjusted baseline magnesium intake was inversely associated with cardiovascular, cancer, and all-cause mortality. Compared with lower consumers, individuals in the highest tertile of magnesium intake had a 34% reduction in mortality risk. Additional studies in different populations are warranted to confirm these results.
Dietary magnesium and stroke
Kathryn M. Rexrode
Division of Preventive Medicine, Brigham and Women's Hospital and Harvard Medical School Boston, MA, USA. email@example.com
Dietary magnesium intake has been linked to significantly reduced risk of stroke in both men and women. In the Nurses’ Health Study 1 and 2, with more than 180,000 women and a total of 3780 incident strokes, women in the highest quintile of magnesium intake had a reduced risk of total stroke OR = 0.89 [95% CI: 0.80, 0.99]) even after adjusting for other risk factors. Similarly, among more than 40,000 men in the Health Professionals Follow-up Study, and 1547 incident strokes, the OR for stroke for men in the highest vs. lowest magnesium intake quintile was 0·83 (95%CI, 0·70-0·99) after full adjustment for other risk factors. In an updated meta-analyses of all prospective studies to date, the combined RR of total stroke was 0.87 (95% CI: 0.83, 0.92) for a 100-mg/d increase in magnesium intake. Moreover, lower magnesium levels at baseline were also linked to higher risk of ischemic stroke in women. Women in the lowest quintile of magnesium levels (
Magnesium in coronary calcification: an epidemiologic approach
Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA, USA. Adela.Hruby@tufts.edu
Many epidemiological studies support a beneficial relationship between dietary or circulating magnesium and risk of cardiovascular diseases (CVD), including hypertension, heart disease, stroke, and atrial fibrillation. Calcification of soft tissue – typically as aortic and coronary artery calcification in CVD – is a noted risk factor for CVD and differentiating predictor of CVD risk. Given magnesium's presence throughout the body, and notably its role in bone, there are likely numerous pathways through which magnesium is acting to mitigate CVD, including the (inhibition of) calcification of soft tissue. At the cellular level, magnesium may passively interfere with calcium in the calcifying apatite matrix, and recent evidence points to an active role of magnesium in inhibiting osteoblastic conversion and calcification of vascular smooth muscle cells.
Relationships between circulating magnesium and/or magnesium intake and soft tissue calcification have long been observed in those with chronic kidney disease, in whom calcification is rapidly accelerated, likely one of many mechanisms leading to earlier CVD in this population. However, evidence regarding the relationship between magnesium and soft tissue calcification in generally healthy individuals has only lately begun to emerge. In these populations, inverse associations between both dietary and circulating magnesium and coronary artery calcification have been reported.
Herewith, some data from the Framingham Heart Study are presented on magnesium in coronary calcification. Also discussed are the complexities of analyzing, in longitudinal population studies, magnesium's relationship with calcification of vascular tissue in particular as a process putatively correlated with osteoporosis.
Mg2+ deficiency results in increased intra-hepatic cortisol levels through NF-kB translocation and inflammatory cytokines production
Andrea Romani, Chesinta Voma
Dept. Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, USA. firstname.lastname@example.org
Tissue and serum Mg2+ deficiency have been observed in several endocrine pathologies including diabetes and metabolic syndrome, but it is still undefined to which extent an altered Mg2+ homeostasis contributes to the onset of these pathologies and/or their complications.
In the present study, we report that Mg2+ deficient hepatocyte exhibit an increased entry of G6P into the endoplasmic reticulum, where the substrate is oxidized by the H6PD to generate NADPH. As H6PD operates in conjunction with 11β-HSD1, the increased level of NADPH is utilized by the latter enzyme to convert inactive cortisone to active cortisol. Administration of cortisone to Mg2+ deficient hepatocytes results in a marked production of cortisol, which in turn enhances gluconeogenesis and alters intrahepatic fatty acid synthesis, thus increasing intrahepatic triglyceride levels. Protein and mRNA expression of H6PD and 11β-HSD1 are both increased 3-4 fold in Mg2+ deficient cells. Mg2+ deficient hepatocytes also exhibit decreased insulin responsiveness, which is further compromised by cortisol production. Returning cellular Mg2+ content to its physiological levels results in a dramatic decrease in cortisol production, and in the progressive renormalization of expression and activity of H6P, 11β-HSD1, and cortisol-responsive genes. Investigation into the underlying mechanism of action suggest that under Mg2+ deficient conditions 11β-HSD1 expression and activity increase as a consequence of increased nuclear translocation of NF-kB and increased expression of inflammatory cytokines (namely IL-1β and/or TNFα). Taken together, our results suggest that by increasing H6PD and 11β-HSD1 activity and expression, Mg2+ deficiency sets the conditions for an increased intrahepatic production of cortisol and a decreased insulin responsiveness. This altered hormonal balance can play a major role in the onset and progression of the metabolic syndrome and its associated complications.
Magnesium in metabolic syndrome
Department of Epidemiology and Biostatistics, School of Public Health-Bloomington, Indiana University, Bloomington, IN, USA. email@example.com
Magnesium is an essential mineral, critical for a number of metabolic functions in the human body. Using a random-effects model, we quantitatively assessed the association between dietary magnesium intake and risk of metabolic syndrome by weighting the relevant published articles. After combining data from six cross-sectional studies including a total of 24,473 individuals and 6,311 cases of metabolic syndrome, an inverse association was found between dietary magnesium intake and the risk of metabolic syndrome. Comparing the highest with the lowest intake group, the risk of metabolic syndrome was lowered by 31% (odds ratio: 0.69, 95% CI: 0.59, 0.81). For every 100-mg/day increment in magnesium intake, the overall risk of having metabolic syndrome was reduced by 17% (odds ratio: 0.83, 95% CI: 0.77, 0.89). Accumulated literature suggests that dietary magnesium intake is inversely associated with the prevalence of metabolic syndrome. Further studies, in particular well-designed longitudinal cohort studies and randomized placebo-controlled clinical trials, are warranted to provide solid evidence and to establish causal inference.
Magnesium, obesity and metabolic disease
Biomedical Research Unit, Mexican Social Security Institute, Durango, México. firstname.lastname@example.org
It has been hypothesized that obesity is related in a cause-effect way with hypomagnesemia; however it has not been appropriately elucidated the directionality of such relationship. We present the results of examining the relationship between body weight status and hypomagnesemia in apparently healthy subjects, and additionally, the results of a recent meta-analysis showing the effect of magnesium supplementation on glucose metabolic disorders.
Regarding the first objective, the adjusted analysis (by body mass index, waist circumference, total body fat, systolic and diastolic blood pressure, and triglycerides levels) showed that hyperglycemia and dietary magnesium intake, but not obesity, are associated with hypomagnesemia.
In addition, the meta-analysis showed that magnesium supplementation for ≥4 months improves fasting glucose and HOMA-IR, but not other issues related with glucose disorders.
Magnesium and chronic kidney disease
Ziad A. Massy
Division of Nephrology, Ambroise Paré Universty Hospital, University of Paris Ouest - Versailles-Saint-Quentin-en-Yvelines (UVSQ), Boulogne Billancourt/ Paris, and Inserm U-1018, Centre de recherche en épidémiologie et santé des populations (CESP), Equipe 5, Villejuif, France email@example.com
Magnesium (Mg) is one of the most important cations in the body, playing an essential role in biological systems as co-factor for more than 300 essential enzymatic reactions. In general population, low levels of Mg are associated with high risk of cardio-vascular diseases (CVD). Despite this growing literature data, the effect of Mg administration on mortality in chronic kidney disease (CKD) patients has never been investigated as primary end-point. We conducted a systematic search of studies assessing the benefits and harms of Mg in CKD (stages 1 to 5 and 5D), and considered all randomized controlled trials (RCTs) and quasi-RCTs evaluating Mg-based interventions in CKD. As a phosphate binder, Mg salts offer the plausible opportunity of double favourable effects via reducing intestinal phosphate absorption and adding potential beneficial effects via increasing circulating Mg levels. Mg supplementation might have a favourable effect on vascular calcification, although the level of evidence is very low. Although longitudinal data describe an association between low serum Mg levels and increased total and cardiovascular mortality, in patients with CKD, the existing RCT reporting the effect of Mg supplementation on mortality failed to demonstrate a favourable effect. As many other variables influencing hard end-points in nephrology, the role of Mg in CKD patients needs to be investigated in more depth, additional research, well-designed and directly targeting the role of Mg being needed as a consequence of limited existing evidence.
Magnesium in the Central Nervous System: recent advances and developments
Sansom Institute for Health Research, University of South Australia, Adelaide, Australia Robert.Vink@unisa.edu.au
A potential neuroprotective role for magnesium in neurological disease has been appreciated for almost three decades, yet translation to the clinical arena has proven elusive. Accumulating experimental evidence continues to support that magnesium plays a critical role in a number of neurological conditions including headache, stress, alcohol/drug intoxication, acute brain injury, seizures, Parkinson's disease and Alzheimer's disease. Simple administration of a magnesium salt in these conditions has not always been therapeutically successful, with a number of studies showing poor penetration of serum magnesium across the blood brain barrier. Several studies have since demonstrated that using a carrier such as polyethylene glycol can address this, simultaneously reducing the dose of magnesium required to achieve the desired central effects while at the same time attenuating deleterious peripheral effects. Alternatively, administering a more permeable magnesium salt, such as magnesium threonate, is seen as the preferred option in more chronic neurological conditions, with positive results having been achieved in experimental models of Alzheimer's disease. Irrespective of the approach, improved central penetration of a magnesium compound that avoids peripheral side effects of high magnesium dosages is clearly a desirable outcome, and should now be investigated in animal models that accurately mimic the complex human condition.
Magnesium and depression
Miguel Ángel Martinez González
Department of Preventive Medicine and Public Health, School of Medicine, University of Navarra, Pamplona, Spain firstname.lastname@example.org
In our systematic review of the literature about magnesium and depression we found 53 cross-sectional studies. A nonsignificant finding was reported by 21 of these cross-sectional studies; 16 cross-sectional studies reported that low levels of magnesium (in blood, tissues or diet) were associated with higher depression risk; on the other hand, 9 cross-sectional studies reported that higher levels were associated with higher risk. The rest of cross-sectional studies reported mixed results. Three cross-sectional studies with a large sample size (>1000, n = 3) reported an inverse association with dietary intake of magnesium assessed with an FFQ. Other 2 large studies using the same methodology did not find any association.
We found only 3 prospective studies and only one of them (the Kuopio cohort, n = 2320) reported an inverse association with hospital discharge-based diagnoses of depression, reporting a hazard ratio = 0.49 (95% CI: 0.25-0.95) between extreme tertiles of magnesium intake (P = 0.035) after 21.3 years follow-up. The other 2 studies (n = 12,939 and n = 475) did not find any association.
We found 22 studies assessing the interactions between antidepressant treatment and magnesium with mixed results. Four of these studies supported the use of magnesium as an adjuvant therapy, but most of these studies did not address or support this hypothesis.
In summary, there is no clear or definitive evidence for the association between dietary magnesium intake and the risk of depression.
Magnesium in anxiety and depression: lesson from a rodent model
Department of Applied Pharmacy, Medical University of Lublin, Poland email@example.com
A variety of neuromuscular and psychiatric syndromes, including different types of depression, were observed in Mg deficiency and the increased Mg level was shown during recovery. Additionally, a low Mg level was found in the cerebral spinal fluid (CSF) of depressed patients who had made suicidal attempts. Moreover, the mood stabilizing properties of Mg have been demonstrated in patients with mania – Mg used as supplementary therapy in mania to lithium, benzodiazepines and neuroleptics, significantly reduced the use of these drugs, and antidepressant drugs (sertraline and amitriptyline) increased Mg levels in erythrocytes. Furthermore, clinical efficacy of Mg treatment was observed in patients with disorders related or accompanying depression (mania, rapid cyclic bipolar disorder, fatigue syndrome).
Altered behavior by Mg-depletion is an animal model of depression and anxiety. Mg deficiency lead to reduction in offensive and to increase in defensive behavior and increase depression- and anxiety-related behavior in animals. Mg administration reduced immobility time in the forced swim test in rodents and enhanced the action of antidepressant drugs in mice (imipramine, citalopram, fluoxetine, tianeptine but not reboxetine). Mg enhanced also antidepressant-like activity of NMDA antagonist and AMPA antagonist reversed activity of Mg in this test. Immobility-induced stress caused depression-like behavior in the forced swim test in mice and Mg treatment provided marked antidepressant activity. The FST increased the Mg concentration in serum and decreased that in the brain compared to naive animals, showing that there is a stress-induced translocation of Mg from the brain into the serum. Moreover, Mg evoked antidepressant-like activity in chronic mild stress and olfactory bulbectomy models. In the elevated plus maze test, Mg produced anxiolytic-like activity and enhanced the action of benzodiazepines. Mechanisms of action of Mg have not yet been fully understood. Probably the main role of Mg in the CNS could be mediated mainly via N-methyl-D-aspartate acid (NMDA) and γ-aminobutyric acid (GABA) and partially by the serotonergic system. In summary, depressive and anxiety syndromes may be connected with low serum Mg. Mg produced antidepressant-like effect in preclinical and clinical studies. The role of Mg in the CNS could be mediated mainly by N-methyl-D-aspartate acid (NMDA) and γ-aminobutyric acid (GABA) receptors.
Magnesium treatment and stress
Elena S. Akarachkova
Research Department of I.M. Sechenov First Moscow State Medical University, Moscow, Russia firstname.lastname@example.org
Patients with chronic stress (100 women aged from 24 to 51 with chronic emotional stress) where treated with Magnesium B6 monotherapy for 8 weeks.
Methods: STAI, SF-36, the value of magnesium in hair by spectrometry, LF/HF ratio by the spectral analysis of heart rate variability in rest and orthostatic test. Statistical analysis: Median (LQ;HQ), chi-square, Wilcoxon test.
Results: The Mg2+ level was 29.85 (26.54; 33.60) mg/kg (the lower limit of normal is 34 mg/kg). The magnesium deficiency was present in 60% of cases. Fewer patients had Mg2+ level in the lower limit of the norm. The anxiety was increased (43 (37; 46) points). The physical and mental components of quality of life were decreased (40% and 30% respectively). The LF/HF ratio in rest was increased (2.8 (2.1; 3.8)) and increased a little in orthotest and was (4.3 (3.6; 4.7)). After the treatment, the Mg2+ level increased (38.93 (34.98; 42.63) mg/kg.) (p<0.05) whereas the anxiety reduced (38 (29; 44) points) (p<0,05). The physical and mental components of health improved (50% (p<0.05)). The LF/HF ratio in rest reduced (1.2 (0.6; 1.6)) (p<0.05) and in orthostatic test - increased (3.5 (3.0; 4.9) (p<0.05).
Conclusion: Mg2+ deficiency was identified in the majority of patients (60%) with chronic stress. The symptoms of stress in the minority of patients (40%) were a result of subcompensated Mg2+ deficiency. Correction of Mg2+ deficiency had a positive impact on patients. The use of bio-organic magnesium salts (citrate and pidolate) with pyridoxine has led to a reduction of the symptoms of stress and improved the quality of life and increased stress resistance. Although this study was uncontrolled, these findings are encouraging and suggest that the Mg2+ plays an important role in the adaptation and stress resistance. Our experience showed the use of Mg2+ may be beneficial in the treatment of stress.
Magnesium, transporters, cells and inflammation
Jeanette A.M. Maier
Department of Biomedical and Clinical Sciences Luigi Sacco, University of Milano, Milano, Italy email@example.com
Magnesium has a role in controlling inflammation. Indeed, it plays an important role in natural and adaptive immunity and also contributes to the integrity of the endothelial layer. Since leukocytes and endothelium are protagonists in inflammation, it is not surprising that low concentrations of magnesium are involved in promoting a pro-inflammatory environment. In the microcirculation, magnesium participates in regulating vascular flow and caliber, permeability, and synthesis of cytokines, chemokines and adhesion molecules. In addition, magnesium controls the production of free radicals and the secretion of cytokines in neutrophils, lymphocytes, macrophages and dendritic cells. Although the ultimate mechanisms are not completely understood, the control of intracellular Ca2+ is an important mechanism by which Mg regulates cellular processes related to inflammation.
The discovery of new Mg transporters, channels and sensors also contributes to a better understanding of the mechanisms of Mg contribution to the inflammatory processes. TRPM7, a divalent cation-permeable channel involved in magnesium homeostasis, has a role in the signalling pathway after B-cell receptor stimulation. Recently, the downregulation of TRPM7 has been shown to reduce the number of migrating T lymphocytes and the mean velocity of the migrating T cells. TRPM7 is also involved in the process of degranulation and release of cytokines mast cells. Magnesium influx mediated by MagT1, a specific magnesium channel, couples T-cell receptor activation to intracellular effectors and regulates the function of CD8+ and CD4+ lymphocytes. TRPM7 associates with, and phosphorylates phospholipase C gamma 2, a pivotal molecule in the signaling pathway following B-cell receptor activation.
Since i) epidemiological studies highlight the association between low Mg intake or status and low grade inflammation, and ii) chronic inflammation is a common denominator to many frequent diseases, further understanding of the mechanisms linking magnesium, its transporters and inflammation appears of great importance.
Role for Mg2+ in immune cell metabolism revealed by MAGT1 immunodeficiency
Michael J. Lenardo
Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA. MLENARDO@niaid.nih.gov
The magnesium ion, Mg2+, is essential for all life as a cofactor for ATP, polyphosphates such as DNA and RNA, and metabolic enzymes, but how it plays a role in intracellular signaling similar to Ca2+ is unknown. We study a cohort of patients with mutations in the magnesium transporter gene, MAGT1, which causes a novel X-linked human immunodeficiency characterized by CD4 lymphopenia, chronic viral infections, and defective T lymphocyte activation. Most prominently, the patients suffer from uncontrolled Epstein-Barr (EBV) infection. We are studying the effects of this Mg2+ deficiency on immune cell metabolism. One observation is that magnesium supplementation improves immune status of the patients and decreases EBV infection and we have been investigating molecular mechanisms of this effect. These observations reveal a role for Mg2+ as treatment for selected forms of immunodeficiency and identify MagT1 as crucial for Mg2+ metabolism.
TRPM7 and its dual action in cancer
Laboratoire de Physiologie Cellulaire et Moléculaire, Université de Picardie Jules Vernes, Amiens, France firstname.lastname@example.org
TRPM7 is an ion channel, mainly permeable for Ca2+ and Mg2+ and therefore contributing to the regulation of calcium and magnesium homeostasis. This function is coupled to an enzymatic activity of the protein carried out by an atypical α-kinase domain located at the cytoplasmic distal c-terminus of each polypeptide subunit.
TRPM7 displays different molecular mechanisms with respect to regulating specific cellular responses and cancer types. It regulates cancer cell physiology by both ion channel function and by kinase activity. In MCF-7 non-invasive estrogen receptor positive (ER+) breast cancer cells, TRPM7 supports cell proliferation in a Ca2+-dependent manner, and TRPM7 silencing accumulates the cells in the S phase of the cell cycle. TRPM7 also regulates cell proliferation of digestive system cancers through Mg2+ influx. Furthermore, TRPM7-mediated calcium Ca2+ or Mg2+ influx is involved in prostate cancer and BxPC-3 pancreatic cell migration, respectively. On the other hand, TRPM7 has been linked to cell migration through phosphorylation of myosin IIA chain independently of Ca2+ and Mg2+ influxes in the highly metastatic ER- breast cancer cells MDA-MB 231. Moreover, in more aggressive pancreatic cancer cell line panc-1, TRPM7 can regulate pro-MMP-2/Hsp90/uPA secretion through its kinase activity leading to cell invasiveness. In breast cancer clinical sample tissues, TRPM7 expression displays a distinct pattern with respect to invasiveness and ER status. Indeed, in ER+ ductal adenocarcinoma, TRPM7 expression is higher in non-invasive cells. In contrast, in ER- ductal adenocarcinoma, its expression is higher in invasive cells from primary tumor sites and matched invaded lymph nodes. Moreover, in pancreatic ductal adenocarcinoma (PDAC), TRPM7 is highly expressed in high grade tumors, and is inversely correlated to patient survival.
In conclusion, we propose that TRPM7 role changes during cancer progression: the early stage tumors TRPM7 is involved in the regulation of cell proliferation and migration as well as in epithelial mesenchymal transition through Ca2+ and Mg2+ homeostasis controls. However, in advanced stages and aggressive tumors, cell migration and invasion require kinase activity and TRPM7 interaction with the cytoskeleton and MMP proteins.
Magnesium in pregnancy and childbirth
Department of Obstetrics and Gynecology, Hillel Yaffe Medical Center, Hadera, Israel MottiH@hy.health.gov.il
Several maternal insults during pregnancy are known as major causes for fetal brain damage, including hypoxia, seizures, and infection. The association between hypoxia and fetal brain damage is well described and proven. Maternal convulsions are also a known cause for deleterious perinatal results. Eclamptic seizures are associated with significant increases in perinatal mortality. Maternal epileptic seizures were found to be associated with an increased incidence of perinatal mortality, as well as cerebral palsy, seizures, and mental retardation in the infants. Maternal intrauterine infection appears to increase the risk of preterm delivery, which in turn is associated with an increased risk of intraventricular hemorrhage, neonatal white matter damage, and subsequent cerebral palsy. IL-1, IL-6, and TNF-alpha have been found associated with intrauterine infection, preterm delivery, neonatal infections, and neonatal brain damage. Unifying models not only postulate the presence of cytokines in the three relevant maternal/fetal compartments (uterus, fetal circulation, and fetal brain) and the ability of the cytokines to cross boundaries (placenta and blood brain barrier) between these compartments, but also postulate how proinflammatory cytokines might lead to intraventricular hemorrhage and neonatal white matter damage during prenatal maternal infection. Interrupting the proinflammatory cytokine cascade might prevent later disability in those born near the end of the second trimester. The mechanisms or pathophysiology of fetal neurotoxicity induced by insult exposure are complex and not fully understood. It is possible that their intrauterine effect is mediated by factors that affect a final common pathway for neuronal injury such as over excitation of the excitatory amino acid receptors. Studies have demonstrated that magnesium can protect against brain injury and NMDA-induced neurodegeneration in neonatal rats, as well as convulsions in adult rats. Parenteral magnesium sulfate administration had a definite protective action on central nervous system oxygen toxicity. It reduced seizure duration and electroencephalogram amplitude in convulsions secondary to oxygen toxicity. Recent studies have shown that prenatal magnesium sulfate exposure was associated with reduced risk for cerebral palsy and possibly mental retardation among very low birth weight children. Three possible mechanisms of action have been postulated: 1. Magnesium may inhibit the NMDA receptor, 2. Magnesium may stabilize vascular tone and thereby decrease endothelial injury, and 3. Magnesium may protect against proinflammatory mediated damage by reducing cytokines and bacterial toxin synthesis. Currently, the common practice is to administer magnesium sulphate to the mother for 2 main indications: 1. Preeclampsia in order to prevent seizure, 2. Preterm labor for fetal neuroprotection.
Magnesium and osteoporosis and fracture risk
Ailsa A. Welch
Department of Population Health and Primary Care, Norwich Medical School, University of East Anglia, Norwich, United Kingdom A.Welch@uea.ac.uk
The impact of osteoporosis and fracture risk on our aging populations is substantial, with estimated costs to health and social care of £2.1bn/year in the UK alone. Sarcopenia (the age related loss of skeletal muscle mass and function) has also recently become recognised as a condition that increases the risk of osteoporosis, falls and fractures. The estimated healthcare costs of sarcopenia are $11.4 bn/per year in the USA.
Magnesium may protect against osteoporosis and fractures during aging through mechanisms that include effects on osteoblast activity and number as well as on hydroxyapatite crystal formation and on regulation of calcium homeostasis. For sarcopenia and skeletal muscle outcomes magnesium may have direct physiological roles as well as attenuating the circulation of low-grade inflammatory cytokines, an established risk factor for loss of skeletal muscle mass and function.
In our study of 4,000 men and women in the UK we found no associations between a measure of bone density (heel bone ultrasound attenuation - BUA and dietary magnesium alone, or with serum magnesium concentrations, although we did find associations between the combined intake of potassium and magnesium with BUA. However, we found a significant association between serum magnesium concentration and incident ‘total’ and ‘spinal’ fractures in men (P trend = 0.02). A recent systematic review largely confirmed these findings noting only 3 previous studies of fracture risk which found no association with magnesium intake and incident fractures, and only a small positive, marginally significant association with BMD. In our other study of twin women a positive association was found between dietary magnesium intake and skeletal muscle mass and power across all ages (18-79 years), although there was no association with grip strength). These findings suggest that magnesium may play an important role in bone and skeletal muscle health during aging.
Data from controlled metabolic unit studies provide guidance for the determination of status indicators and dietary requirements for magnesium
Forrest H. Nielsen, Lu Ann K. Johnson
USDA, ARS, Grand Forks Human Nutrition Research Center, Grand Forks, ND, USA
Determination of whether magnesium is a nutrient of public health concern has been hindered by questionable Dietary Reference Intakes (DRIs) and problematic status indicators. Balance data since 1997 suggest that the current magnesium Estimated Average Requirement (EAR) and Recommended Dietary Allowance (RDA) in the United States and Canada are too high. Data indicate that the EAR and RDA should be about 175 and 250 mg/d, respectively, for70 kg healthy individuals. These DRIs decrease or increase based on body weight. Urinary excretion data from tightly-controlled metabolic unit balance studies indicate that 40 to 80 mg (1.65 to 3.29 mmol) Mg/d are excreted when magnesium intakes are250 mg/d. However, the change from low to high urinary magnesium excretion with an increase in dietary magnesium intake occurs within a few days and vice versa. Thus, urinary magnesium as a stand-alone status indicator would be most useful for population studies. The current reference range for normal serum magnesium is 0.75 to 0.96 mmol/L (1.82 to 2.33 mg/dL). Controlled metabolic unit depletion/repletion experiments show that serum magnesium concentrations decrease only after a prolonged depletion if an individual starts the depletion after several weeks of consuming a diet providing approximately 300 mg magnesium/day. Individuals with serum magnesium concentrations in excess of 0.75 mmol/L (1.82 mg/dL), or as high as 0.85 mmol/L (2.06 mg/dL), might be magnesium-deficient because such individuals respond to magnesium supplementation. Controlled metabolic unit studies suggest that a combination of a dietary intake
Magnesium supplementation and magnesium transporters in pre-hypertensive subjects
Mariana Rodríguez R1, Fernando Guerrero2, Miguel A. Reyes Romero1
1 Department of Biomedical Sciences, University Juárez of Durango State, Méx., 2 Biomedical Research Unit, Mexican Social Security Institute, Durango, Mexico.
Purpose: The aim of this study was to evaluate the efficacy of magnesium supplementation in decreasing blood pressure and assess its effect in the transcription of TRPM6, TRPM7 and SLC41A1 magnesium transporters.
Materials and Methods: A blind randomized placebo-controlled clinical trial. 34 subjects with pre-hypertension, men and no pregnant women from 30 to 65 years old were included, 16 cases and 18 controls. The intervention group was supplemented with magnesium lactate pills; both groups were followed for 4 months. Expression profile was performed using mRNA obtained of leukocytes from seven controls and seven subjects of the intervention group by qRT-PCR.
Results: A statistical significant difference (p<0.0005) was found between intervention and control group in the following variables: systolic blood pressure, diastolic blood pressure, fasting glucose, HDL-c, magnesium. A higher expression of the TRPM6 was found in the intervention group. No difference was found in the expression of TRPM7 and SLC41A1 transporters.
Conclusion: Magnesium supplementation decreased systolic blood pressure and caused overexpression of TRPM6 suggesting that this gene is involved in the regulation of systolic blood pressure.
Effect of magnesium supplementation on glucose metabolism: a systematic review and meta-analysis of double-blind randomized controlled trials
Nicola Veronese1, Sara Fernando Watutantrige2, Claudio Luchini3,4, Marco Solmi5,6, Giovanni Sartore7, Giuseppe Sergi1, Enzo Manzato1,8, Mario Barbagallo9, Ragnar Rylander10, Stefania Maggi11, Brendon Stubbs12
1 Department of Medicine, DIMED, Geriatrics Section, University of Padova, Italy, 2 Department of Medicine, DIMED, Endocrinology Unit, University of Padova, Italy, 3Department of Pathology, University of Verona, Verona, Italy, 4Surgical Pathology Unit, Santa Chiara Hospital, Trento, Italy, 5National Health Care System, Padua Local Unit ULSS 17, Italy, 6Department of Neuroscience, University of Padova, Padova, Italy, 7Department of Medicine, Diabetology and Dietetics Service, Padova University, Padova, Italy, 8 National Research Council, Neuroscience Institute, Padova, Italy, 9 Geriatric Unit, Dept. of Internal Medicine and Geriatrics, University of Palermo, Palermo, Italy, 10 BioFact Environmental Health Research Center, Lerum, Sweden, 11Physiotherapy Department, South London and Maudsley NHS Foundation Trust, London SE5 8AZ, UK, 12 Health Service and Population Research Department, Institute of Psychiatry, King's College London, De Crespigny Park, London SE5 8AF, UK.
Purpose: Although higher dietary intakes of magnesium (Mg) seem to correspond to lower diabetes incidence, the research about Mg supplementation in diabetes and conditions at higher risk of diabetes is still limited. We therefore aimed to investigate the effect of oral Mg supplementation on glucose and insulin sensitivity parameters in participants with diabetes or at higher risk of diabetes compared to placebo.
Materials and Methods: A PubMed, EMBASE, SCOPUS until 01/31/2016 was made without language restrictions. Eligible were randomized controlled trials (RCTs) investigating the effect of oral Mg supplementation vs. placebo in patients with diabetes or in conditions at higher risk of diabetes. Data were summarized using standardized mean differences (SMD) with their 95% confidence intervals (CIs).
Results: Eighteen RCTs (12 in people with diabetes and 6 in people at high risk of diabetes) were included. Compared to placebo (n = 334), Mg treatment (n = 336) reduced fasting plasma glucose (studies = 9; SMD = -0.40; 95%CI: -0.80 to -0.00; I2 = 77%) and glycosylated hemoglobin levels (8 studies; SMD = -0.24; 95%CI: -0.45 to -0.04; I2 = 20%) in people with diabetes. In conditions at higher risk of diabetes (Mg: 226; placebo = 227 participants), Mg supplementation significantly improved plasma glucose levels after a 2hOGTT (3 studies; SMD = -0.35; 95%CI: -0.62 to -0.07; I2 = 0%) and trend level significant reductions in HOMA-IR (5 studies; SMD = -0.57; 95%CI: -1.17 to 0.03; I2 = 88%).
Conclusion: Mg supplementation appears to have a beneficial role in improving glucose parameters in people with diabetes and improves insulin-sensitivity parameters in those at higher risk of diabetes.
Magnesium supplementation and counseling on glycemic and genomic outcomes among overweight pregnant women
Michelle Cho1, Katherine Brennan1, Simin Liu1-3
1 Department of Obstetrics and Gynecology, University of California at Los Angeles (UCLA), 2 Department of Medicine, Alpert School of Medicine, 3 Department of Epidemiology and Center for Global Cardiometabolic Health, Brown University, USA.
Purpose: To determine metabolic and clinical efficacies Magnesium (Mg) supplementation versus placebo as well as dietary counseling on overweight and obese pregnant women.
Materials and Methods: We conducted a placebo-controlled intervention trial where 28 overweight and obese pregnant women in their first trimester were randomized into 3 arms in parallel to take either 1) 300 mg of elemental Mg in citrate form, 2) an identical appearing placebo, or 3) nutritional counseling on how to increase magnesium intake for ∼28 weeks until delivery. The primary outcomes were serum metabolic and inflammatory markers (Mg, glucose, insulin, hemoglobin A1C (HbA1c), high sensitivity C-reactive protein (hsCRP), E selectin, Sex hormone binding Globulin (SHBG), TNFαR2 and IL6) before and after intervention. Secondary outcomes included analysis of endothelial progenitor cells in cord blood collected at delivery, mRNA expression of VEGFR2 and TRPM6 in placental tissue, as well as clinical pregnancy outcomes.
Results: Serum markers for Magnesium, glucose, insulin, HbA1C, and SHBG were not significantly different at baseline across the three groups confirming the success of randomization. HbA1C levels at the 2nd trimester (adjusting for the baseline value) were statistically significantly different between groups with lowest HgbA1C levels observed in the dietary counseling group (p = 0.03). Patients enrolled in the dietary counseling arm had a statistically significant increased Magnesium intake by nutritionist intake/questionnaire (p = 0.04). Further, we observed significant differences in VEGFR2 and TRPM6 placental mRNA expression (varied by several orders of magnitudes) across the 3 comparison groups.
Conclusion: Dietary counseling about following a Mg rich diet or Mg supplementation appears to be effective in improving glycemic status, metabolic intermediaries, and genomic expression of VEGFR2 and TRPM6 among overweight pregnant women.
Clinical Trials Registration number: NCT01510665
Chronic exercise down-regulates expression of magnesium-responsive genes in blood cells of diabetic patients
1Department of Physical Medicine and Rehabilitation, Taichung Tzu Chi Hospital, Taichung, Taiwan, 2Division of Endocrinology and Metabolism, Taichung Veterans General Hospital, Taichung, Taiwan, 3Stem Cell Center, Department of Medical Research, Taichung Veterans General Hospital, Taichung, Taiwan, 4Institute of Veterinary-Physiology, Freie Universitat, Berlin, Germany
Purpose: Exercise is an effective therapy in diabetes care as it helps to regulate glucose and magnesium (Mg) homeostasis. Nevertheless, the mechanisms by which exercise exerts effects on Mg2+ transport remain unclear. The present study investigated expression of genes encoding for Mg2+ transporters (GMTs) after chronic exercise in diabetics.
Materials and Methods: A total of fifteen adult patients with diabetes mellitus type 2 were recruited and underwent a three-month indoor bicycle exercise program. Expression of five GMTs (CNNM2, TRPM6, TRPM7, SLC41A1, SLC41A3) were determined in blood samples. Relevant anthropometric values and biochemical parameters were also determined.
Results: Fasting blood glucose, glycosylated hemoglobin, waist circumference, and Mg levels decreased after the exercise program (p<0.05). Expression of all five GMTs were down-regulated after exercise, but only CNNM2, TRPM6, and TRPM7 showed significantly lower expression (p<0.05) compared with that before the exercise program as shown in figure 1. In addition, glycosylated hemoglobin was inversely correlated with expression of SLC41A3 (p = 0.03), and waist circumference was inversely correlated with expression of TRPM6 and TRPM7 after the exercise program (p < 0.05).
Conclusion: The three-month exercise program ameliorated blood glucose levels and downregulated expression of magnesium responsive genes in patients with type 2 diabetes. Expression of CNNM2, TRPM6, and TRPM7 correlated well with glycosylated hemoglobin and waist circumference.
TRPM7 kinase domain modulates macrophages and T-lymphocytes infiltrated in kidneys and spleens induced by aldosterone and salt treatment
FJ Rios, KY Hood, A Harvey, K Neves, P Anyfanti, R Nosalski, LL Camargo, AC Montezano, RM Touyz
Institute of Cardiovascular and Medical Sciences, University of Glasgow, United Kingdom
Introduction: TRPM7 is a channel linked to a kinase domain, permeable to magnesium and calcium with important function in cell proliferation and survival. We previously found that cells deficient in the TRPM7-kinase domain exhibited a pro-inflammatory phenotype stimulation. Here, we investigated the effects of the kinase domain in immune cell infiltration in the kidney and spleens in mice treated with aldosterone and salt.
Methods: Wild-type (WT) or heterozygote TRPM7-kinase domain (TRPM7+/-) mice were infused with aldosterone (600μg/Kg/day) and NaCl 1% in drinking water (aldo/salt) for 4 weeks. Lymphocytes and macrophages in kidneys and spleens were evaluated by flow cytometry.
Results: Aldo-salt increased 35% of kidney mass in TRPM7+/- and WT. Kidneys from WT but not TRPM7+/- increased ROS production (1.7-fold) and albuminuria (6.4-fold) after aldo-salt treatment. Kidneys from untreated TRPM7+/- presented increase in inflammatory infiltrated (0.87 × 106 vs WT 0.22 × 106 cells/g), lymphocytes CD3+CD4+T cells (27% vs WT, 19%) and macrophages F4/80+ cells (47% vs WT, 31%). Kidney macrophages presented reduction in the M2-phenotype marker CD206 (2% vs WT 3.6%). Aldo-salt treatment increased the spleen mass (40%) only in WT, but not in TRPM7+/-. Spleens TRPM7+/- presented increase in inflammatory infiltrated (3.7×108 vs WT 2.0×108 cells/mg) and macrophages (8.8% vs WT 5.9%). Splenic macrophages TRPM7+/- presented increase in CD206 M2-marker (16% vs WT 7%), higher frequency of TCD4+ (68% vs WT, 50%) and TCD8+ (26% vs WT, 17%). WT aldo-salt presented similar cell population in kidneys and spleens as untreated TRPM7+/- animals. No further changes were observed in kidneys or spleens from TRPM7+/- aldo-salt.
Conclusion: Our data provide insights into the importance of the TRPM7-kinase domain in the activation of the immune system, which when down regulated provokes an increase in inflammatory cell infiltration in kidneys and spleens. These novel findings highlight a potential protective role of TRPM7- kinase in immune regulation.
The effects of magnesium supplementation on subjective stress and anxiety: a systematic review
Neil Boyle1, Clare Lawton1, Elena Akarachkova2, Louise Dye1
1 School of Psychology, University of Leeds, Leeds, UK, 2 First Sechenov Moscow State Medical University, Moscow, Russia
Purpose: to examine the effects of magnesium supplementation on parameters of subjective anxiety and stress.
Materials and Methods: A systematic search of interventions with magnesium (Mg) alone or in combination (up to 5 additional ingredients) was performed in March 2016. Ovid Medline, PsychInfo, Embase, CINAHL and Cochrane databases were searched using equivalent search terms. Healthy adults, free from a clinical diagnosis of depression were included. Samples recruited on the basis of mild anxiety, hypertension, or Premenstrual Syndrome (PMS), were retained.
Results: 2094 citations were retrieved. After inclusion/exclusion criteria were applied, 16 studies were retained including 3 unpublished studies. Mg doses ranged between 100-600 mg. Lactate, citrate and oxide were the most commonly used Mg forms. Seven studies combined Mg with vitamin B6, and 2 with Hawthorn extract. There were 7 studies in mild-moderate anxiety, 6 of which used the Hamilton Anxiety Scale as an outcome measure. Seven studies were conducted in PMS using menstrual cycle symptom rating scales and 2 studies in hypertension employed quality of life (QoL) outcome measures. Eleven studies were placebo-controlled whilst 3 employed a positive verum, e.g. Lorazepam. The majority of studies that recruited anxious samples showed a reduction in reported anxiety but no difference between Mg and pharmaceutical treatment (n = 3). In these placebo-controlled studies, there was a marked placebo response. Four of the 7 studies in PMS showed significant reductions in anxiety-related symptoms although only 2 of these appropriately compared effects against placebo treatment. Both interventions in hypertension were placebo-controlled with one study reporting higher QoL after 12 weeks treatment with Mg.
Conclusion: The quality of studies was generally poor. Studies that included a placebo condition often failed to evaluate effects appropriately. Taken together, studies in stress & anxiety and PMS suggest that Mg could confer benefits, but well-designed randomised controlled trials are required.
Magnesium in addictions
Department of Pharmacology, Gr T Popa University of Medicine and Pharmacy, Iasi, Romania
Addiction is one of the most important medical and social problems today. About 160 substances can induce addiction in human body. The molecular mechanisms involved in addiction are very complex. Magnesium decreases the intensity of addiction to opiates and psychostimulants (cocaine, amphetamine, nicotine), cannabinoids and other addictive agents. Low cellular and plasma levels of magnesium facilitate the development of addiction and the occurrence of relapses and resuming consumption of addictive substances after treatment of addictive patients. Magnesium also reduces the intensity of withdrawal syndrome in opiates and alcohol addicted peoples and the amounts of cocaine used. The main antiaddictive mechanisms of magnesium are the decrease of dopamine presynaptic synthesis and release in some brain areas (mesolimbic system, nucleus accumbens and ventral tegmentum), reduction of glutamate stimulation of NMDA receptors, increase of GABA system activity and reduction of brain NOS activity. Substance P is also involved in addiction. The inhibition of synthesis of this neuropeptide by Mg 2+ can reduce the addictive effects. Hypomagnesemia increases the vulnerability to addiction. Our data indicate that magnesium stimulates reward system but does not induce addiction. The rewarding effect of Mg2+ could be a mechanism in preventing the development of addictions. A way by which chronic stress favors the development of addiction is the reduction of magnesium level in the body. There are data that indicate that magnesium administration in medical practice can reduce the intensity of addiction.
Magnesium modulates doxorubicin activity through drug lysosomal sequestration and trafficking
Valentina Trapani, Francesca Luongo, Daniela Arduini, Federica I. Wolf
Istituto di Patologia Generale, Facoltà di Medicina e Chirurgia “A. Gemelli”, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, Rome I-00168, Italy
Purpose: Magnesium is a well-known regulator of cell growth and survival. Nonetheless, its role in cancer biology and therapy is highly controversial. On one hand, magnesium deficiency can promote many steps of carcinogenesis and tumor development in in vivo animal models; on the other, chemotherapeutic-induced hypomagnesemia may improve therapy outcome in some clinical settings. Therefore, we sought to investigate whether magnesium availability can modulate cellular responses to the widely used chemotherapeutic doxorubicin, and tried to identify the possible underlying molecular mechanisms.
Materials and Methods: We used an in vitro model that has been extensively characterized in our laboratory, i.e. mammary epithelial HC11 cells adapted to grow in different Mg concentrations, and MCF7 human breast carcinoma cells. Drug sensitivity was evaluated by MTT test. Intracellular drug uptake, retention and trafficking were assessed by confocal microscopy of the naturally fluorescent doxorubicin molecule. TRPM7 channel expression was detected by Western blotting.
Results: We found that high magnesium availability correlated with diminished sensitivity both in cells chronically adapted to high magnesium concentrations, and in acutely magnesium-supplemented cells. Such decrease in sensitivity resulted from reduced intracellular doxorubicin accumulation, due to altered drug lysosomal sequestration and trafficking. Magnesium supplementation correspondingly modulated expression of the TRPM7 channel.
Conclusion: We propose that TRPM7, which is known to control cytoskeletal organization and dynamics, might represent the missing molecular link between extracellular magnesium availability and intracellular signal transduction leading to different cellular sensitivity to doxorubicin. Our findings suggest that magnesium availability may affect response to therapy in cancer patients.
New targeted fluorescent sensors for the study of intracellular magnesium distribution and mobilization
Mohammad S. Afzal, Jessica J. Gruskos, Guangqian Zhang, Daniela Buccella
Department of Chemistry, New York University, New York, USA
Purpose: To develop fluorescent indicators for organelle-specific visualization and quantification of cellular Mg2+
Materials and Methods: Fluorescent sensors incorporating triazoles and tetrazines were synthesized by modification of reported methods2. Sensor characterization was performed in PIPES buffer at pH 7. Magnesium detection in live HeLa cells was tested by widefield microscopy. Tetrazine sensors were applied to HEK293T cells expressing HaloTag fusions to Histone H2A and Golgi localization sequence, treated with BCN-Cl. Organelle targeting was assessed by fluorescence colocalization with organelle stains in microscopy images.
Results: An alkynylbenzothiazole with an APTRA magnesium recognition unit was synthesized and employed as precursor for assembly of triazole-based ratiometric sensors incorporating organelle-targeting moieties. The sensors display low millimolar dissociation constants suitable for detection of intracellular free Mg2+. A sensor containing an arylphosphonium group showed preferential accumulation in mitochondria, enabling real-time imaging of fluctuations of free Mg2+ within this organelle during early stages of apoptosis in HeLa cells. Seeking a more general methodology for organelle-targeted magnesium detection, a two-step strategy was designed, based on a fluorescent indicator functionalized with a tetrazine quencher. Bioorthogonal attachment of the sensor to HaloTag fusion proteins expressed in cellular compartments of interest results in sensor anchoring and local activation of the fluorescence signal within the organelle, with ∼10 fold enhancement upon protein conjugation. Resulting sensor hybrids combine fast response characteristic of small-molecule fluorescent sensors with ease of localization of genetically encoded proteins. The new strategy displayed general applicability; targeted detection of free Mg2+ in nuclei, Golgi and in whole HEK293T cells was achieved.
Conclusion: Small-molecule fluorescent indicators can be functionalized with organelle-targeting moieties to direct their subcellular localization. A general strategy for local activation of the fluorescence via fluorogenic bioorthogonal reactions within organelles enables the constraining of the signal to compartments of interest. These new sensors and staining methodologies enable imaging of intracellular metal mobilization with subcellular resolution and low background.
TRPM7 and MagT1 are critical in the osteogenic differentiation of human bone mesenchymal stem cells
Sara Castiglioni, Alessandra Cazzaniga, Valentina Romeo and Jeanette A.M. Maier
Department of Biomedical and Clinical Sciences Luigi Sacco, University of Milano, Milano, Italy
Purpose: Human bone mesenchymal stem cells (bMSC) possess capacity for self-renewal and multilineage differentiation potential into osteoblasts, chondrocytes and adipocytes. Upon specific stimuli, bMSC are induced to differentiate into osteoblasts, which deposit new bone matrix. Since previous studies demonstrated that intracellular magnesium homeostasis is important for osteogenic differentiation of bMSC, we investigated the expression of two magnesium transporters, TRPM7 and MagT1, during bMSC differentiation into osteoblasts. Moreover, we transiently silenced TRPM7 or MagT1 to understand the role of the two transporters in osteogenic differentiation of bMSC.
Materials and Methods: bMSC were isolated from adult human bone marrow withdrawn from healthy volunteers. For in vitro osteogenic differentiation, confluent bMSC were cultured in a medium containing 2×10-8 M 1α,25-Dihydroxyvitamin D3, 10 mM β-glycerophosphate and 0.05 mM ascorbic acid. The expression of TRPM7 and MagtT1 was analyzed by Real-Time PCR. Osteogenic differentiation was monitored by the expression with Real-Time PCR of runt-related transcription factor 2 (RUNX2), osterix (OSX), collagen 1A1 (COL-1A1), osteocalcin (OCN) and osteopontin (OSP). To obtain a transient downregulation of MagT1 and TRPM7, we utilized the stealth siRNAs developed by Qiagen.
Results: We demonstrate that the expression of TRPM7 and MagT1 increased during the osteogenic differentiation of bMSC, with a maximum increase after 6 days of culture in the osteogenic medium. Thereafter, their expression declined but remained significantly higher than in controls also after 10 days of differentiation. MagT1 silencing during the first 3 days of osteogenic differentiation induced the expression of TRPM7; conversely TRPM7 silencing induced the expression of MagT1. In both cases we showed a significant induction of the osteogenic markers.
Conclusion: Our results indicate that i) both TRPM7 and MagT1 expression is modulated during the osteogenic differentiation of bMSC and ii) both TRPM7 and MagT1 play an essential role in osteogenic differentiation.
Magnesium and its effect on human osteoclasts and osteoblasts differentiation
Lili Wu1,2, Frank Feyerabend1, Arndt F. Schilling2, Regine Willumeit-Römer1, Bérengère J.C. Luthringer1
1 Institute of Materials Research, Division of Metallic Biomaterials, Helmholtz-Zentrum Geesthacht (HZG), 21502 Geesthacht, Germany, 2 Department of Plastic Surgery and Hand Surgery, Klinikum Rechts der Isar, Technical University Munich (TUM), D-81675 Munich, Germany
Purpose: Magnesium (Mg) alloys have been identified as a new generation material of orthopedic implants Degradation of Mg-based implants has been shown to increase the bone mass around the implant. However, the contribution of osteoblasts and osteoclasts is still open to discussion. Therefore, the aim of the present study was to analyze the direct effect of increased magnesium concentrations on the differentiation and function of human osteoclasts in mono and in coculture with osteoblasts.
Materials and Methods: Pre-osteoclasts (derived from human peripheral blood mononuclear cells or PBMC) were cultured with or without human osteoblasts and increased concentration of magnesium extract for up to 28 days. To follow the effect of (I) Mg-extract and (II) osteoblast on osteoclast differentiation, several cell-specific parameters were studied (e.g., for osteoclasts: TRAP staining and resorption assays/for osteoblasts: alkaline phosphatase activity and mineralization staining).
Results: Results showed that higher concentrated Mg extract could lead to a promotion in the formation of osteoblasts and may have an inhibitory effect on the differentiation of osteoclasts. The Mg extract dual mode of action on the bone cell levels could contribute to enhanced bone formation or turn-over caused by implantation of Mg-based alloys. Compared to monoculture, PBMC in coculture with osteoblasts exhibited higher tolerance to high Mg extract.
Conclusion: Cocultures consisting of both bone cells (osteoblasts and osteoclasts) are a useful model for in vitro cytocompatibility assessment of Mg-based implants and are believed to mimic closer in vivo. Future work would focus on more mechanistic approach as well as elucidation of cell–cell communication.
Permeation of topically applied magnesium ions through human skin is facilitated by hair follicles
Navin Chandrakanth Chandrasekaran1,2, Washington Y. Sanchez2, Yousuf H. Mohammed2, Jeffrey E. Grice2, Michael S. Roberts2,3, Ross T. Barnard1
1 School of Chemistry and Molecular Biosciences, Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, 4072 Australia, 2 Therapeutics Research Centre, School of Medicine, Translational Research Institute, The University of Queensland, 37 Kent St. Woolloongabba, Queensland, 76131, Australia, 3 School of Pharmacy and Medical Sciences, University of South Australia, City East Campus, North Terrace, Adelaide, South Australia, 5001, Australia
Purpose: Magnesium is an important micronutrient essential for various biological processes and its deficiency has been linked to several inflammatory disorders in humans. Some anecdotal evidence and a few published results have attributed amelioration of inflammatory skin conditions to the topical application of magnesium. On the other hand, transport of magnesium ions across the protective barrier of skin, the stratum corneum, is contentious. Our primary aim in this study was to estimate the extent of magnesium ion permeation through human skin and the role of hair follicles in facilitating the permeation.
Materials and Methods: We topically applied deionised water (milliQ) (vehicle control) and 5mM MgCl2 solution (pH 7.2) for 30 minutes using the “donor” (upper) chamber of a Franz cell on human skin obtained from abdominoplasty. We also applied 5mM MgCl2 to skin that was tape stripped 30 times, in order to facilitate the permeation of magnesium through epidermis and represent a positive control. We treated another set of excised skin in the same way as above, with 52 mM and 1.9 M MgCl2 solutions (pH 7.4 and 7.8 respectively) for 5, 15, and 60 minutes to study the effect of time and concentration in magnesium permeation. We then cryosectioned these treated skin and stained the sections with Mag-fura-2 dye. We used a LaVision Biotec Nikon multiphoton system with a tunable titanium Sapphire laser to visualize skin sections.
Results: Cryosections of human skin pre-treated with 5 mM MgCl2 solution showed increased fluorescence intensity relative to sections that were not pre-treated, when stained with Mag-fura-2 dye. Higher fluorescence intensities relative to sections untreated with MgCl2, were observed at 15 and 60 minutes after the skin was exposed to 1.9 M MgCl2 concentration (p<0.05, one way ANOVA) and after 60 minutes of exposure to 52 mM MgCl2 (p<0.01, one way ANOVA). When 1.9 M MgCl2 solution was topically applied over plugged and unplugged skin for 15 minutes, we found that Mag-fura-2 fluorescence intensity was higher in unplugged skin section
Conclusion: Upon topically applying magnesium solution, we found that magnesium penetrates through human stratum corneum and it depends on concentration and time of exposure. We also found that hair follicles make a significant contribution to magnesium penetration.
Identification of natural and synthetic modulators of the TRPM7 channel
Vladimir Chubanov, Sebatian Schäfer, Silvia Ferioli, Thomas Hofmann, Susanna Zierler, Thomas Gudermann
Walther-Straub-Institute of Pharmacology and Toxicology, LMU of Munich, Goethestrasse 33, 80336, Munich, Germany
Transient receptor potential cation channel subfamily M member 7 (TRPM7) is a multifunctional protein comprising a TRP ion channel segment linked to an α-type protein kinase domain. Genetic inactivation of TRPM7 revealed its central role in Mg2+ metabolism, cell motility, proliferation and differentiation. The channel activity of TRPM7 is tightly controlled by levels of cytosolic Mg2+ ([Mg2+]i). TRPM7 is associated with anoxic neuronal death, cardiac fibrosis and tumor progression. Recently, we have identified several pharmacological compounds inhibiting or activating the TRPM7 channel, such as benzimidazole NS8593 and phenanthrene naltriben. Remarkably, the stimulatory effect of naltriben on TRPM7 was found to be unaffected by the physiological levels of [Mg2+]i. In contrast, the inhibitory action of NS8593 on TRPM7 was highly dependent from [Mg2+]i. Here, we demonstrate that mibefradil and NNC 50-0396, two benzimidazole relatives of NS8593, are positive modulators of the TRPM7 channel. The response to mibefradil was fast, reversible, and reproducible. In contrast to naltriben, mibefradil efficiently activates TRPM7 currents only at physiological intracellular levels of [Mg2+]i, and its stimulatory effect was fully abrogated by high [Mg2+]i. Finally, we observed that the effect of mibefradil was selective for TRPM7 among various TRP channels examined. Hence, mibefradil acts as a [Mg2+]i-regulated modulator of the TRPM7 channel.
Quantification and mapping of intracellular magnesium in single cells by an innovative approach using X-ray synchrotron-based techniques
Giovanna Farruggia1, Concettina Cappadone1, Emil Malucelli1, Agnese Procopio1, Azzurra Sargenti1, Chiara Frassineti2, S. Parenti2, Stefano Iotti1
1 Dipartimento di Farmacia e Biotecnologie, Università di Bologna, Via San Donato 19/2, 40127 Bologna, 2 Dipartimento di Scienze Biomediche, Metaboliche e Neuroscienze, Università di Modena e Reggio Emilia, Via Campi 287, Modena, Italy
Purpose: This study aimed to clarify the role of Magnesium in cell signaling pathways by monitoring its cellular concentration and compartmentalization. A new analytical approach based on Synchrotron X-ray imaging techniques allows to obtain intracellular elemental maps in different proliferative status. X-Ray fluorescence microscopy (XRFM) and X-Ray transmission microscopy (STXM) were carried out at Elettra synchrotron (Trieste) on chemically fixed cells. Recently, we developed an algorithm, which combines X-ray information to Atomic force microscopy (AFM), permitting to obtain Mgintracellularconcentration map on single cells.
Materials and Methods: Sarcoma cells (SaOS-2) were grown in Mg2+-deprived MEM medium with 0.5% dialyzed FBS for 24 hours. Then, serum-starved cells were stimulated by 5% FBS addition, in presence or absence of 1 mM MgCl2. To determine the chemical imaging and quantify the total Mg2+ in single cells, the cells were plated at 1×104 cells/cm2 density on 200-nm-thick silicon nitride membrane window.
Results: Quiescent cells resulting from serum starvation did not proliferate without Mg2+ when they were stimulated with FBS, and are arrested in G0/G1 phase. The arrest was characterized by a significant increase in the expression levels of the inhibitor protein p27Kip1, and correlated with the intracellular decreased Mg2+ concentration. The intracellular Mg molar concentration map obtained by this multimodal approach, confirmed the inverse correlation between Mg and the proliferative status. Mg was mainly confined in the plasma membrane when the cells were arrested, while it moved toward internal areas when the cells proliferated after FBS stimulation.
Conclusion: In conclusion, integration of structural and functional information is a powerful tool to increase the knowledge in magnesium biochemistry. However, most of the biochemical processes occurring in cells during the development and progression of osteosarcoma still remains largely undefined.
The work was supported by grants RFO of Bologna University and Cassa di Risparmio di Modena.
Biodegradable Mg implants: how to bring them into the clinics
Frank Feyerabend1,Regine Willumeit-Römer1,2
1 Institute of Materials Research, Division Metallic Biomaterials, Helmholtz-Zentrum Geesthacht, 2 Christian-Albrechts-Universität zu Kiel, Technische Fakultät, Institut für Materialwissenschaft Biologische Grenzflächen von Implantaten, Kiel, Germany
In recent years, many efforts have been made to bring degradable implants based on magnesium for cardiovascular and orthopedic applications into the clinical application. In 2013, the first CE-mark for a magnesium implant was conceded. However, due to the degradability of the material, standards developed for permanent implants are not directly applicable. Also, in comparison to degradable polymers the degradation mechanisms are very different, hindering the application of standards developed for this area.
As methodology has improved a lot recently, the correlation between in vivo and in vitro can be attributed by various factors: (1) the application of physiological environments including the introduction of flow and/or mechanical loading; (2) the choice of adequate degradation solutions (e.g. full blood, cell culture media or simple salt solutions) and (3) the application of implantation site specific environments including cells.
The talk will give an overview about the present knowledge about (1) the degradation mechanisms, (2) the influence of material processing on the degradation and (3) and suitable in vitro setups. It will conclude with prerequisites for the development of clinically applicable implants.
An investigation into the effects of seawater-derived magnesium on cellular function using organotypic modelling techniques
Robert G. Wallace1,2, Laura Twomey1,2, Brian Fitzpatrick3, Phil Cummins2, Ronan P. Murphy1,2
1 Cell and Molecular Biology Group, School of Health and Human Performance, 2 Dublin City University, 3 Clogherhead, Co. Louth, Ireland
Purpose: Seawater comprises numerous different materials, including dissolved minerals from earth's crust and those released from water-dwelling organisms. Magnesium (Mg) is ubiquitous (approximately 1300 ppm) in such water. Magnesium is a micro-nutrient, critically involved in membrane function, muscle contraction, protein assembly and DNA replication. It is also an essential co-factor in many enzymatic reactions. Mg supplementation is becoming increasingly utilised in maintaining physiological health, particularly that of the cardiovascular system. Water solubility presents a significant challenge in formulating such supplements, as it occurs naturally as a crystalline structure. Therefore, extraction of Mg from seawater, using seawater itself as a diluent medium, circumvents this problem. While molecular mechanisms controlling Mg2+ levels in the body are not well understood, TRPM7 (Transient receptor potential cation channel, subfamily M, member 7) has been identified as a key regulator of whole body Mg2+ homeostasis, and associated with Mg deficiency in vascular endothelial cells. Hence, effects of seawater-derived Mg as a dietary supplement on both vascular and dermal cells were investigated to determine if supplementation could reverse effects of TRPM7 over-expression.
Materials and Methods: The xCELLigence® real-time cell monitoring system was used to analyse cell adhesion and migration in response to different Mg concentrations in both dermal fibroblast and keratinocyte cells.Organotypic modelling of vasculature using the Ibidi® perfusion system to simulate blood-flow over human aortic endothelial cells (HAECs), followed by qRT-PCR to assess TRPM7 gene expression.
Results: Induced HAEC inflammation via oscillatory blood-flow drives over-expression of TRPM7.Mg uptake at 0.3% is cyto-protective and no increase of TRPM7 was observed in mineral-treated HAECs.Experiments demonstrate that Mg supplementation has potential to improve fibroblast cell health and dynamics, improve wound healing and regenerative capacity, and improve biomechanical properties of skin.
Conclusion: Vascular and dermal aging may be significantly affected by Mg availability and uptake.
Pregnant women with symptoms of magnesium deficiency in Russian Federation: MAGIC 2 study results
Alexander D. Makatsariya1, Viktoria O. Bitsadze1, Dmitry V. Blinov2, Olga A. Gromova3, Eliso M. Dzhobava4
1 I.M.Sechenov First Moscow state Medical University, Moscow, 2 Sanofi-aventis group, Moscow, 3 Ivanovo State Medical Academy, Ivanovo; Russian Center of UNESCO Institute for Microelements, Moscow, 4The Pirogov Russian National Research Medical University, Moscow, Russia
Purpose: Mg deficiency (MD) high incidence (81.2%) in pregnant women with MD symptoms was shown in the previous Russian epidemiological study (MAGIC) covered mainly big cities with high-income levels. To extrapolate this finding to populations in smaller cities throughout Russia and to evaluate how MD is managed in routine practice, MAGIC2 study was conducted in 12 cities with increased sample size, age and life-style distributions.
Materials and Methods: Non-comparative, prospective observational program was conducted (disease registry) which included pregnant women (at any trimester) ≥18 years with clinical manifestations suggestive of MD (e.g. leg cramps, etc.). Data were collected at Visit 1 and follow-up Visit 2 (4 weeks ± 1 after Visit 1). MD was diagnosed based on serum Mg level (
Results: 2127 pregnant women, mean age 28.1 ± 5.1 years were enrolled in 200 sites, 10 women were excluded due to data doubtful accuracy. MD incidence considering serum Mg level and MDQ scoring was 58.4% (436/747) and 78.4% (1660/2117), respectively. Subjects experienced MD based on at least one test constituted collectively 80.9% (1713/2117). Magnesium was prescribed in most cases (99.3%). Physicians commonly prescribed organic Mg salts (lactate in 9.6%, citrate in 89.5% cases) in combination with pyridoxine. No serious AEs were reported. Inverse correlation between MDQ score (reflecting symptoms severity) and serum Mg level (-0.274, р<0.001)), and relatively high MDQ sensitivity (87.8%) were observed.
Conclusions: High MD incidence in Russian pregnant women with MD clinical manifestations was confirmed. MDQ was considered valuable for MD screening. Organic Mg salts (lactate, citrate) in combination with pyridoxine were commonly prescribed to pregnant women with MD clinical manifestations.
Observational study of outpatient women in hormone dependent conditions with magnesium deficiency and receiving Magne B6® Forte in Russia (MAGYN Study)
Alexander D. Makatsariya1, Eliso M. Dzhobava2,Viktoria O. Bitsadze1, Olga A. Gromova3, Dmitry V. Blinov4
1 I.M.Sechenov First Moscow state Medical University, Moscow, 2 The Pirogov Russian National Research Medical University, Moscow, 3 Ivanovo State Medical Academy, Ivanovo, RU; Russian Center of UNESCO Institute for Microelements, Moscow, 4 Sanofi-Aventis group, Moscow, Russia
Purpose: Mg deficiency (MD) accompanying hormone-dependent (sex steroids) conditions in women has long been of clinical interest. MAGYN is the first large-scale Russian study aimed to describe the profile of outpatient women with hormone-dependent conditions experiencing MD symptoms and to evaluate Magne B6® Forte (MB6F) clinical effectiveness in such patients.
Materials and Methods: An observational study included disease (cross-sectional part) and product (longitudinal part) registries performed in 21 Russian cities. Cross-sectional part (performed at Visit 1) included 9168 women subdivided into 6 equal groups (receiving hormonal contraception, with premenstrual syndrome, with climacteric syndrome not receiving or receiving HRT, with osteoporosis, fertile women with any other sex steroids hormone-dependent condition) of whom 2101 subjects with confirmed MD (using MD questionnaire (MDQ) and/or blood Mg level (BML)) and prescribed MB6F within routine practice were included in longitudinal part. In longitudinal part MB6F effectiveness was estimated using dynamic MDQ scoring and/or BML measurement after 4 weeks of treatment (at Visit 2).
Results: Patients profile was characterized with a high prevalence of similar symptoms associated with MD and hormone-dependent conditions. MD prevalence (MDQ data) varied from 67.3% (hormonal contraception group) to 82.1% (osteoporosis group). The level of magnesium in blood at diagnosis of MD ranged from 0.70 ± 0.18 mmol/L in the group of patients, taking hormonal contraceptives, up to 0.73 ± 0.23 mmol/L in the group of patients with premenstrual syndrome. Of women prescribed MB6F, average MDQ score reduced from 46 ± 12.7 to 29.2 ± 15.1 points and average BML increased from 0.65 ± 0.14 to 0.79 ± 0.23 mmol/L). Subjective effectiveness and tolerability were assessed by physicians as “very well” and “well” in most cases (89.4% and 92.4% respectively). 38 AEs reported in 30/2101 patients (1.43%) No serious AEs occurred.
Conclusions: MD high prevalence in women with hormone-dependent conditions experiencing symptoms of MD was revealed. Magne B6® Forte increased blood magnesium level, reduced MD, improved patient status, demonstrating clinical effectiveness and good tolerability.
Is magnesium a key factor for redox balance in athletes?
CP Monteiro1, CN Matias1,2, M Bicho3, H Santa-Clara2, E Rock5, Y Rayssiguier4, MJ Laires1
1 Physiology and Biochemistry of Exercise Laboratory, CIPER, FMH, Univ Lisboa, Portugal, 2 Exercise and Health Laboratory, CIPER, FMH, Univ Lisboa, Portugal, 3 Institut of Scientific Research Bento de Rocha Cabral, Lisboa, Portugal, 4 Unité de Nutrition Humaine, INRA, Centre Clermont–Ferrand/Theix, France
Purpose: In athletes, Mg intake is frequently below recommendations which may increase susceptibility to oxidative damage. In strenuous exercise is often hypothesized that ROS production may overwhelm the antioxidant defences resulting in adverse effects on health and performance. We aim to investigate the redox balance of adult-competitive swimmers against recreational exercise practitioners, controlling for Mg intake.
Materials and Methods: Fifteen high competition male swimmers (S) and 16 active men (AM), not involved in any regular sport activity (all aged 18-25 years), were recruited.
Oxidative damage markers in plasma and red blood cells (RBC), antioxidant enzymes in RBC, muscle damage markers and non-enzymatic antioxidants in plasma were evaluated by photometry (with the exception of thiobarbituric reactive substances (TBARS), assessed by fluorimetry).
Results: Controlling for the exercise level, we observed inverse correlations between: uric acid and glutathione reductase (GR) or susceptibility of RBC to peroxidation (RBCPx); plasma adrenaline oxidase activity (AdOx) and carotenoids; TBARS and GR or VitE; and direct correlations between: AdOx and creatine kinase (CK) or TBARS; CK and GR or RBCPx; TBARS and VitE.
Controlling for Mg intake in addition to exercise level revealed new inverse correlations between: carotenoids and TBARS or lactate; and new direct correlations between: lactate and AdOx or TBARS; cortisol and AdOx, CK, lactate dehydrogenase (LDH), or Meta-Hemoglobin reductase. The associations between uric acid and RBCPx, between AdOx and CK or TBARS, and between GR and RBCPx lost their significance. All the others associations remained significant.
Conclusion: These outcomes suggest that the coordination between the antioxidant defences may be partially modulated by magnesium, which may be the result of its ability to stabilize cell membranes and oxidation targets, such as adrenaline.
Effects of the TRPM7 kinase domain in vascular dysfunction and fibrosis induced by aldosterone and salt
FJ Rios, KY Hood, A Harvey, K Neves, P Anyfanti, R Nosalski, LL Camargo, AC Montezano, RM Touyz
Institute of Cardiovascular and Medical Sciences, University of Glasgow, United Kingdom
Introduction: TRPM7 is cation channel with intrinsic kinase activity, important for cellular Mg2+ homeostasis. We recently showed that TRPM7-kinase plays a role in aldosterone-mediated vascular effects and that aldosterone-mediated inflammation is exacerbated in the absence of the TRPM7-kinase. Here we explored the putative role of TRPM7-kinase in cardiac fibrosis and vascular function in aldosterone-induced hypertension in mice.
Methods: Wild-type (WT) or heterozygote TRPM7-kinase domain (TRPM7+/-) mice were treated with infused with aldosterone (600 μg/Kg/day) and NaCl 1% in drinking water (aldo/salt) for 4 weeks. Blood pressure (BP) was evaluated by tail-cuff. Vessel function was investigated in mesenteric resistance arteries by myography. Protein expression of pro-fibrotic molecules were assessed by western-blot and histology.
Results: Aldo/salt increased BP in TRPM7+/- and WT to similar levels (137 mmHg vs control 118 mmHg). Mesenteric arteries from untreated TRPM7+/- mice are more sensitive to relaxation induced by acetylcholine (Ach) (LogEC50: 7.6 ± 0.1 vs 7.1 ± 0.2, TRPM7+/- and WT, respectively), effects that were reduced by aldo/salt treatment (LogEC50: 7.2 ± 0.1). Phenylephrine-contraction and sodium nitroprusside-relaxation were similar among groups. Pressure myography showed that in WT, aldo/salt increase the diameter (26%) and cross-sectional area (40%), resulting in hypertrophic outward remodelling, whereas in TRPM7+/-, the treatment decreased the diameter (16%) and increase the wall/lumen ration (82%), resulting in eutrophic inward remodeling. Untreated TRPM7+/- mice had increased plasma galectin-3 (2.5ng/mL) vs WT (1.4ng/mL) and protein expression for fibronectin (2.4-fold) and TGFβ (2-fold) in hearts, which were similar to WT-aldo/salt.
Conclusion: Our results suggest anti-fibrotic effects of the TRPM7 kinase domain, since TRPM7+/- mice presented increase in heart fibrotic markers. However these mice already exhibit vascular remodelling compared to WT. Our findings provide some insights into aldosterone signaling through TRPM7 kinase and suggest that this chanzyme may have some protective actions, which when downregulated, promotes cardiac fibrosis in aldosterone-induced hypertension.
Molecular mechanisms of characteristic hypermagnesiuria and magnesium supplementation-induced blood pressure lowering in obese type 2 diabetic rats
1 Ishikawa Kinenkai Kawagoe Ekimae Clinic, Kawagoe, 2 Department of Nephrology and Hypertension, Saitama Medical Center, Saitama Medical University, Kawagoe, Japan
Purpose: Renal magnesium excretion increases from the early phase of diabetes, which is a principal cause of characteristic hypomagnesemia in 15%–50% of diabetic patients. Additionally, it is also known that the magnesium supplementation lowers blood pressure. However, the involvement of renal magnesium transporting molecules in those phenomena has not been studied yet.
Materials and Methods: Kidneys were obtained from male OLETF (F) and LETO (L) rats of 16, 24, and 34 weeks-old. MgSO4 (Mg: 10 g/L) was daily administered in some animals via drinking water after 16 weeks. Expression of claudin-16, tight-junctional magnesium-permeable molecules in TAL part of nephron, and transient receptor potential (TRP) M6, magnesium channel in DCT part of nephron, was studied by RT-PCR and immunohistochemistry.
Results: Renal Mg excretion in F, assessed by UMgV and FEMg, was significantly higher than L in the weeks of 24 and 34. Expression of TRPM6 in F was down-regulated in all weeks, which was synchronized with down-regulation of thiazide-sensitive NCC, one of principal regulator of TRPM6 expression. However, expression of claudin-16 was not altered in F at all weeks. Average blood pressure was significantly elevated in F compared with that in L. Moreover, blood pressure in F + Mg was significantly lower than that in F. However, this difference was not significant between L + Mg and L (F: 125.0 ± 1.2, F + Mg: 119.2 ± 1.5, L: 95.4 ± 0.9, L + Mg: 95.5 ± 0.9 mmHg).
Conclusion: Decreased Mg reabsorption in DCT part of the nephron by the down-regulation of TRPM6 might be a principal cause for hypomagnesemia in diabetes patients. The down-regulation of NCC might be involved in the altered TRPM6 expression. However, it is suggested that the mechanism behind the blood pressure-lowering effect of magnesium supplementation is independent of altered expression of magnesium transporting molecules.
Magnesium, other electrolytes, vitamin D in blood plasma and erythrocytes of patients with spasmophilia
Katarzyna Torunska1, Adriana Palinska-Saadi2, Anna Suska2, Magdalena Maj-Zurawska2
1 Private Neurologist Practice, Warsaw, 2 Faculty of Chemistry, University of Warsaw, Warsaw, Poland
Purpose: Latent tetany, spasmophilia, is more and more prevalent in society. Spasmophilia pathology, wherein the substrate is an increase in the excitability of the nerve-muscle, follows magnesium deficiencies and/or hyperventilation. Spasmophilia is usually accidentally detected on the basis of electromyographic test. While overt tetany signs are widely known and attacks are easy to recognize, spasmophilia is usually detected by chance in apparently healthy people, complaining on very unusual symptoms from various organs and systems. Spasmophilia signs are resulting from reduction intracellular magnesium concentration and not from reduction serum magnesium concentration. At this moment, this illness can be identified on the basis of ischemic test. Reliable test can result from determination magnesium concentration in erythrocytes.
Materials and Methods: 200 adult patients were diagnosed as having spasmophilia on the basis of electromyographic test. Their blood plasma and erythrocytes after lysis were analysed in view of total magnesium, ionized magnesium, total calcium, ionized calcium, potassium, sodium, chlorides as well as vitamin D concentration. Clinical potentiometric analyzer Microlyte 6 (KONE, Espoo, Finland) and clinical analyzer Indico Plus (Thermo Scientific, Espoo, Finland) were used.
Results: Concentration of electrolytes is within normal range in blood plasma. However, ionized magnesium and ionized calcium are at lower level of the normal range. The concentration of vitamin D in blood plasma is at lower level of normal range. In erythrocytes, both ionized magnesium and total magnesium concentrations are below normal range. The difference is statistically significant. Ionized calcium concentration seems to be at higher level of normal range. Total calcium concentration is at lower level of normal range. Potassium concentration is at lower level of normal range.
Conclusion: Our research proved the usefulness of both total and ionized magnesium concentration in erythrocytes as parameters to evaluate spasmophilia. These parameters can be also helpful in observing effects of the therapy.
Magnesium in inflammatory bowel diseases: expression of magnesium transporters
Daniela Arduini1, Valentina Petito2, Willem Hamersma1, Valentina Trapani1, Angelica D’Agostini2, Antonio Gasbarrini2, Franco Scaldaferri2, Federica Wolf1.
1 Institute of General Pathology, Catholic University of the Sacred Heart, Rome, 2 Department of Internal Medicine, Gastroenterology Division, “A. Gemelli” Hospital, Catholic University of the Sacred Heart, Rome, Italy
Background: Magnesium is an essential mineral that is fundamental in many pathophysiological processes. A mild hypomagnesaemia is a common condition associated to dietary deficiency of magnesium. Hypomagnesaemia is a well-known enhancer of oxidative stress and inflammation. Inflammatory Bowel Disease (IBD) is a collection of chronic inflammatory bowel diseases characterised by a variety of nutritional deficiencies due to reduced absorption and/or increased loss of essential nutrients, which among other conditions, can induce hypomagnesaemia.
Objective: To investigate the influence of magnesium availability in the diet on murine dextran sodium sulphate (DSS)-induced acute colitis and its effects on magnesium transporters (TRPM6 and TRPM7).
Methods: Mice were exposed to 2.5% DSS in the drinking water and fed three different diets (low (30 mg/kg), normal (1000 mg/kg) and high (4000 mg/kg) magnesium content). Both acute colitis (5 days exposure to DSS) and recovery after the acute colitis (7 days of recovery without DSS) were studied. The severity of the colitis was scored daily using a four point Disease Activity Index (DAI) based on the faecal consistency, weight loss and faecal blood loss. Colon, kidney and serum were collected at the sacrifice. Magnesaemia was analysed using atomic absorption spectrometry and the expression of TRPM6 and TRPM7 by RT-PCR.
Results: Dietary magnesium deficiency increased the severity of the DSS-induced colitis as scored with the Disease Activity Index, whereas magnesium supplementation seemed to score more or less like controls. Serum magnesium measurements showed that while magnesium in the diets positively correlated with the magnesaemia, the exposure to DSS reduced magnesaemia in all conditions. However, high magnesium content in the diet compensated for DSS-induced hypomagnesaemia.The expression of TRPM6 and TRPM7 was analysed in kidney (positive control) and colon. Results show that as expected in kidney TRPM6 expression is inversely related to hypomagnesaemia. TRPM7 is down regulated by DSS treatment. As to the colon we observed that the expression of both TRPM6 and TRPM7 correlated with hypomagnesaemia.
Conclusion: Magnesium availability affects the severity of IBD. High magnesium diet partially compensates inflammation-induced hypomagnesaemia. The expression of TRPM6 and TRPM7 magnesium transporters are affected by IBD. Our data suggest an active role of magnesium in the pathogenesis and in the severity of colon inflammatory diseases. The validation of these results in IBD patients is currently under study.
Magnesium in inflammatory bowel disease: a Cinderella story
Valentina Petito1, Daniela Arduini2, Valentina Trapani2, Willem Hamersma2, Francesca Luongo2, Cristina Graziani1, Vincenzo Arena2, Antonio Gasbarrini1, Franco Scaldaferri1, Federica I. Wolf2
1 Department of Internal Medicine, Gastroenterology Division, “A. Gemelli” Hospital, Catholic University of the Sacred Heart, Rome, 2 Institute of General Pathology, Catholic University of the Sacred Heart, Rome, Italy
Purpose: Deficient magnesium intake or low serum concentrations of magnesium are associated with numerous pathological conditions that share inflammatory stress as a risk factor, which is also a consequence of magnesium (Mg2+) deficiency. Low magnesium status is a very common nutritional deficiency, but unfortunately is often under-recognized Colonic mucosa plays a key role in magnesium absorption and homeostasis in the whole body. Patients with inflammatory bowel disease (IBD) show high levels of pro-inflammatory cytokines (i.e., TNF-α), and present with anorexia and cachexia. Therefore, a decrease of Mg2+ intake could be hypothesized, that may exacerbate disease. The aim of this study is to investigate the influence of magnesium availability in the diet on the severity of acute colitis in a murine model.
Methods: Mice were exposed for 5 days to 2.5% dextran sodium sulphate (DSS), followed by 7 days of recovery without DSS, and fed with three different diets (low (30 mg/kg), normal (1000 mg/kg) and high (4000mg/kg) Mg2+ content). The severity of the colitis was scored daily using the four points Disease Activity Index (DAI). Colon, kidney and serum were collected at the sacrifice. Magnesaemia was analysed using atomic absorption spectrometry. Inflammation score was assessed on immunohistochemical samples.
Results: Dietary Mg2+ deficiency induced hypomagnesaemia. DSS reduced magnesaemia in all dietary conditions. However, high Mg2+ diet compensated for DSS-induced hypomagnesaemia. Dietary Mg2+ availability inversely correlated with the severity of DSS-induced colitis. Low Mg2+ diet enhanced mucosal damage and impaired mucosal recovery; conversely, Mg2+ supplementation protected the colonic mucosa against DSS-induced damage.
Conclusions: Mg2+ supplementation protects the colonic mucosa, by compensating hypomagnesaemia and inflammation, likely contributing to the mucosal healing. Our data suggest an active role of Mg2+ in the progression of colon inflammatory diseases. The validation of these results in IBD patients is currently under study.
Effect of inflammation on muscle function in a murine colitis model: the contribution of magnesium
Valentina Petito1, Valentina Trapani2, Francesca Luongo2, Daniela Arduini2, Cristina Graziani1, Loris R Lopetuso1, Vincenzo Arena2, Antonio Gasbarrini1, Franco Scaldaferri1, Federica I Wolf2
1 Department of Internal Medicine, Gastroenterology Division, “A. Gemelli” Hospital, Catholic University of the Sacred Heart, Rome, 2 Institute of General Pathology, Catholic University of the Sacred Heart, Rome, Italy
Purpose: Inflammation is an important contributor to the etiology of diseases implicated in skeletal muscle dysfunction. A number of diseases and disorders including inflammatory bowel diseases (IBD) are characterized by chronic inflammation, malabsorption, maldigestion, increased energy expenditure, and gastrointestinal protein loss that may induce a relative deficiency of energy or proteins. Diarrhoea and occult blood loss increase the loss of zinc, potassium, magnesium, iron. The aim of this study is to investigate the influence of magnesium intake on muscular activity, and to assess whether expression of the magnesium channels TRPM7 and MAGT1 could be correlated with muscular function in an experimental colitis model.
Materials and Methods: Mice were exposed for 5 days to 2.5% dextran sodium sulphate (DSS), followed by 7 days of recovery without DSS, and fed with three different diets (low (30 mg/kg), normal (1000 mg/kg) and high (4000 mg/kg) Mg2+ content). The severity of the colitis was scored daily using the four points Disease Activity Index (DAI). The rota rod performance test was used to evaluate the effects of colitis on skeletal muscle dysfunction. Colon, muscle and serum were collected at the sacrifice. Magnesaemia was analysed using atomic absorption spectrometry. Muscle morphology was assessed by immunohistochemistry. Channel expression was assessed by real time RT-PCR.
Results: Dietary Mg2+ deficiency increased the severity of the DSS-induced colitis. Low Mg2+ diet enhanced muscular damage, assessed as loss of skeletal muscle mass and a deregulated skeletal muscle physiology; conversely, Mg2+ supplementation showed protective effects. Magnesium channels were modulated both by diet and DSS treatment in muscle tissues.
Conclusions: Muscle activity is compromised during colitis, probably due to inflammatory cytokines. Our results show a protective effect exerted by dietary magnesium on muscle function in this condition. Further studies are in progress to identify the underlying molecular mechanisms linking expression of the magnesium channels to intracellular signal transduction.
The involvement of claudin-16 down-regulation in the mechanism of characteristic hypermagnesiuria in tubulo-interstitial nephropathy
1 Saitama cardiovascular and respiratory center, Kumagaya, 2Department of Nephrology and Hypertension, Saitama Medical Center, Saitama Medical University, Kawagoe, Japan
Purpose: We attempted to elucidate the mechanism of hypermagnesiuria associated with tubulo-interstitial nephropathy (TIN). For this purpose, we examined the correlation between time-differential development of TIN and the changes in the mRNA expression of renal magnesium-transporting molecules by rats with unilateral ureter obstruction (UUO).
Materials and Methods: The left kidney was sampled at day-0 (control), day-1 (early phase) and day-7 (late phase) after ligation of the left ureter of male SD rats. The development of TIN was assessed by immunohistochemistry and RT-PCR of fibrosis-related genes. The expression of claudin-16 and transient receptor potential (TRP) M6 were also studied.
Results: The immunohistochemistry and gene expression of MCP-1 and TGF-ß showed that TIN was not apparent in the early phase but was significant in the late phase of UUO. (the interstitial area: 18.6 ± 1.3% at day-0, 18.8 ± 1.1% at day-1, 32.1 ± 2.5% at day-7, MCP-1: 105.1 ± 14.8% at day-0, 132.9 ± 25.7% at day-1, 302.7 ± 32.7% at day-7, TGF-β: 101.1 ± 7.6% at day-0, 93.6 ± 4.1% at day-1, 338.9 ± 20.7% at day-7). In addition, density of peritubular capillaries were diminished in the late phase but not in the early phase. The gene expression of claudin-16 was decreased in the late phase (day-0: 100.2 ± 2.9%, day-1: 90.3 ± 6.3%, day-7: 36.4 ± 1.6%). Immunohistochemistry showed an apparent reduction of the immunoreactivity of claudin-16 in the late phase. The expression of TRPM6 was reduced even in the early phase.
Conclusion: The present results may indicate that the characteristic hypermagnesiuria in TIN is principally caused by a dysfunction of magnesium reabsorption in the TAL resulting from a significant decrease in the claudin-16 expression. The down-regulation might be closely related to the development of TIN, or renal ischemia.
Effect of magnesium on inflammation using platelets as circulating functional biomarkers in blood
Laura C. Twomey1,2, Robert Wallace1,2, Philip Cummins3, Ronan P. Murphy1,2,3
1Cell and Molecular Biology Group, 2School of Health and Human Performance, Dublin City University, 3Centre of Preventative Medicine, Dublin City University, Ireland, 4Invent Business Centre, Dublin City University, Ireland
Purpose: Cardiovascular Disease (CVD) is a name given to a group of disorders of the heart and blood vessels. Platelet activation is central to CVD progression. Most CVDs may be prevented by addressing modifiable risk factors such as diet. Previous studies have demonstrated the benefits of elements on circulating platelet function and microvesicles (MV). However, technical issues have prevented large-scale screening and functional intervention studies. Magnesium (Mg is involved in essential cellular processes regulating cardiovascular function and has been linked to associated conditions such as platelet activation (thrombosis). Reduced platelet activation could be a potential mechanism whereby Mg confers its cytoprotective benefits. We determined if Mg could modulate the platelet inflammatory response by regulating platelet MV release.
Materials and Methods: These assays were used to monitor ex vivo effects of Mg during human intervention studies (both dietary and lifestyle interventions). The Impact-R cone and plate device was used for testing platelet function (adhesion and aggregation) using 130ul of blood under arterial flow conditions. Blood was incubated and pre-treated with various concentrations of Mg prior to functional analysis with the Impact-R. Results are expressed as the percentage of the well surface covered by platelets, representing adhesion and the average size of the aggregates representing platelet aggregation. Platelet MV release during shear stress was investigated. Following removal of the blood sample after arterial shear exposure, it was centrifuged to produce platelet free plasma (PFP). PFP MV levels were analysed by surface expression of CD42b and CD62P using flow-cytometry on a Guava EasyCyte8HT.
Results: Optimal concentrations of MG reduced platelet aggregation by 22-33 % in all subjects. Platelet adhesion levels remained unchanged. Overall PFP MV counts were decreased in treated samples. Platelet microparticle (CD62P+) release upon shear stress was reduced in samples treated with Mg.
Conclusion: We have demonstrated using ex vivo testing technology that Mg has beneficial effect on platelet function- reducing hyper aggregation under stress conditions without affecting adhesive properties (i.e. potentially blocking aberrant thrombus formation while maintaining the adhesive function) Platelets and MVs are highly reflective of dietary and lifestyle changes, and therefore, extremely sensitive biomarkers of human health.
ATAMg®, a new taurinergic magnesium vector in migraine may result in significant wellbeing improvement in some people: case report
D Forget, P Danhier, C Durlach
Biosciences SPRL, France
Background: N-ATAMag® provides magnesium in a unique bioavailable form, the N-Acetyltaurine (ATAMg®) i.e. taurine beta amino acid where a sulfonic acid group has been acetylated on the amino function. This N-acetylation removes taurine zwitterion structure and provides ATAMg® with a lipophilic character which facilitates both Mg and taurine passage through membrane phospholipids in particular into neuronal cells. ATAMg® is a structural analog to 2 major neurotransmitters involved in neuro excitation: kainic acid and glutamic acid. ATAMg® takes place of the transmitter at the receptor level and acts as a kainic acid inhibitor. Migraine headache is thought to be caused by a distension of meningeal blood vessels and alteration of pain perception trough the activation of trigeminal sensory neurons and local brain over-sensitization. Migraine attacks result from insufficient NMDAR and AMPAR activation/trafficking regarding persistent KAR activation. High levels of hormones in luteal phase result in intra cell Mg reduction and pro-inflammatory mediator's release. Furthermore, lack in taurine mobilization related to intra cell Mg deficiency, results in altered pain perception. Finally, intra cellular magnesium deficiency leads to deficient NMDAR role.
Clinical case: EC, a woman aged 27, is prone to migraine attacks since aged 17 years. Initially, migraine attacks were preceded by aura but spontaneously resolved after few months. After a riding accident in 2013, migraine attacks re-started, mostly with aura. Frequency was once to twice a month for migraine attacks with aura and once a week for migraine attacks without aura. This resulted progressively in study disruption. EC was treated with Oxetorone as baseline treatment. Amenorrhea, depressive syndrome and related anxiety appeared. Eliptriptan was added for acute episodes with or without aura. Because insufficient migraine attacks relief, ibuprofen was taken as self-medication during acute episode. On top of amenorrhea and uncontrolled depressive syndrome, EC was facing numerous side effects including nausea, drowsiness, dizziness, tingling sensation, dry mouth leading to work stoppage or serious discomfort at work. Complete medication arrest was decided and replaced with N-ATAMag®1 and CoQ102; dietary rules were provided. After 2 months of this new lifestyle, migraine attacks drop down to 1 acute episode a month which is easily relieved by lighting decrease. No side effect or work stoppage was reported.
Conclusion: More natural and physiopathological therapeutic approach of migraine attacks with long-term usage ATAMg® 350 mg twice daily, combined to wealthy lifestyle and nutrition, may result in significant wellbeing improvement in migraineurs. ATAMg® may also facilitate migraine attack treatment.
Magnesium influence on tramadol rewarding effect
Mihai Nechifor1, Diana Ciubotariu1, Cristina Gales2
1Department of Pharmacology; 2Department of Histology; Gr. T Popa University of Medicine and Pharmacy, Iasi, Romania
Background: Tramadol (trans-(+/−)-2-[(dimethyl-amino) methyl]-1-(3-methoxyphenyl) cyclohexanol hydrochloride,) is a centrally-acting analgesic with opioid and non-opioid actions that is effective to reduce pain.
Methods: We tested tramadol action at the level of reward system and magnesium influence on this tramadol effect. The tramadol action on reward system was tested by conditioned place preference (CPP) method using a three compartment box apparatus. The conditioning box was connected to a computer and the time spent in each compartment was recorded. The conditioning procedure was conducted in 4 phases: habituation, pre-conditioning, conditioning and post-conditioning phase. The first group each rat received in conditioning phase saline solution 1 mL ip, the second group received on conditioning 1, 3, 5 and 7 days tramadol 40 mg/kg i.p and the third group received in same days tramadol 40 mg/kg i.p. + MgCl2 10 mg/kg ip. (2h before tramadol).The last group received in conditioning phase only MgCl2 10 mg/kg i.p. The results were statistically interpreted to compare post-conditioning vs. pre-conditioning time in each group and to compare the groups.
Results: The obtained data indicate that magnesium (10 mg/kg) has a stimulating effect of CPP in naïve rats. Tramadol increased CPP (221 ± 21.3 s vs 321.5 ± 30.5 s, p<0.01). Magnesium associated to tramadol significantly increased the CPP stimulating effect of tramadol (321.5 ± 30.5 s tramadol vs 403.3 ± 28.9 s tramadol + MgCl2, p<0.05).
Conclusion: Magnesium increases the rewarding effect of tramadol. This action could be important for of pain suppressing effect of this analgesic drug.
Behavioural aspects of hypomagnesaemia in albino mice
Anna D. Serefko, Aleksandra Szopa, Żaneta Żeleźnik, Łukasz Byra, Katarzyna Świąder, Ewa Poleszak
Department of Applied Pharmacy, Medical University of Lublin, Lublin, Poland
Purpose: The significance of magnesium ions in the development of affective disorders is not disputable and experimental magnesium deficiency has been proposed as a depression model. However, this proposed depression model has not been fully characterized. The available data do not define the exact time frame in which the occurrence of mood disturbances can be attributed to magnesium deficiency. The main goal of our study was to investigate the impact of magnesium intake with the daily diet on behavioral changes in animals over time.
Materials and Methods: The experimental studies were carried out on male Albino Swiss mice. The forced swim test (FST), the tail suspension test (TST), and the elevated plus maze (EPM) were used to evaluate the depressive-like and anxiety-like behaviors, respectively. Spontaneous locomotor activity and body mass of animals were measured in order to filter out false positive/negative results.
Results: The obtained data show that three and six-week consumption of a low magnesium-containing diet (i.e., below 0.02% of magnesium) induced prolonged immobility in the TST and increased the percentage of both entries into the open arms as well as the time spent in the open arms in the EPM. Mice behavior was not altered considerably after the 1st week of the experiment. Throughout the study, overall levels of spontaneous locomotor activity and weight gain in the groups of animals on the low magnesium-containing diet were not significantly different from those observed in the control groups receiving magnesium-adequate diet (i.e., containing 0.2% of magnesium).
Conclusion: Our findings confirm that magnesium deficiency may be one of the factors involved in etiology of depression and anxiety. Therefore, magnesium-rich foods should be included in everyday diet. The outcomes may be inspiration for further studies on the response to antidepressant drugs in subjects with insufficient magnesium intake.
Association of chronic magnesium deficiency and increased microvascular stiffness in patients with dementia – a possible prognostic and therapeutic tool?
Bodo von Ehrlich1,Sepp Porta2
1 Practice of internal medicine Kempten, Germany, 2 Stresscenter, Dillach, Austria
Several epidemiological studies have pointed out either association of Mg deficiency with dementia or microvascular alterations with dementia. Preliminary data show an association of Augmentation index (AIX), a non-invasive parameter of microvascular stiffness, with magnesium depletion. AIX is a biomarker associated with CV-mortality.
Purpose is to establish non-invasive simple and feasible parameters of treatable microvascular disease possibly involved in the development of dementia.
Materials and Methods: Among 224 patients of our practice of internal medicine tested for pulse wave velocity (PWV) and AIX with a Mobilograph ® device (Oct. 2015-march 2016) we also have long term data of magnesium status. In this context the Mg/Ca quotient in serum seems to be a more practical and sensitive indicator of magnesium load and/or turnover than serum Mg alone. A serum Mg/Ca quotient near 0.4 is considered as good, the range below, especially between 0.36 and 0.28, rather represents moderate to severe Mg deficiency. In this pilot study we analysed a subgroup of patients (n = 14) mean age 82 y, 12 f/2 m with documented symptoms of dementia, including determinations of the Mg/Ca-quotient and AIX.
Results: All the patients with dementia had long term (4-11J) documented Mg deficiency - often in spite of supplementation recommendation and remarkable high AIX values of 24-59% (mean 37.2%) and an 11 of 14 higher vascular ager than the age control. Preliminary data showed that Mg infusion lowered AIX as an immediate effect slightly even after 30min of Mg infusion. Preliminary observations show a similar effect with oral supplementation although this took some months.
Conclusion: From the pathophysiological point of view, microvascular disease of CNS und intracellular Mg depletion might be cofactors which contribute to the development of dementia. Both can be detected simply with tools of ambulatory medicine and both can be therapeutically influenced. We regard the results of our pilot group as a basis for a hypothesis that diagnostic application of both parameters may better characterize the development of dementia or subgroups thereof, justifying further studies to establish the correlation of diagnosis and illness progress as well as warranting further prospective therapeutic investigations.
Study of the interactions between magnesium, ketamine and morphine on temperature response and acute nociception in rats
Katarina Savić Vujović1, Sonja Vučković1, Aleksandar Vujović2, Nevena Divac1, Branislava Medić1, Radan Stojanović1, Dragana Srebro1, Milica Prostran1
1Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, Belgrade, 2Hospital for ENT, KBC “Dragiša Mišović”, Serbia
Purpose: Study is aimed at evaluating the effects of ketamine and magnesium sulphate on body temperature and acute nociceptive pain in rats and examination whether magnesium sulfate added to ketamine or morphine-ketamine combination produces higher level of analgesia and higher effect on body temperature.
Materials and Methods: Analgesic activity was assessed by tail-immersion test in male Wistar rats (200-250 g). The body temperature was measured by insertion of a thermometer probe 5 cm into the colon of unrestrained rats.
Results: Magnesium sulphate (5 and 60 mg/kg, sc) showed influence neither on baseline, nor on morphine-evoked hyperthermic response. Subanesthetic doses of ketamine (5-30 mg/kg, ip) given alone, produced significant dose-dependent reduction in both baseline colonic temperature and morphine-induced hyperthermia. Analysis of the log dose–response curves for the effects of ketamine and ketamine-magnesium sulphate combination revealed synergistic interaction, and about 5.3 fold reduction in dosage of ketamine when the drugs were applied in fixed ratio (1:1) combinations. In addition, fixed low dose of magnesium sulphate (5 mg/kg, sc) enhanced the temperature lowering effect of ketamine (1.25-10 mg/kg, ip) on baseline body temperature and morphine-induced hyperthermia by factors of about 2.5 and 5.3, respectively. Magnesium sulfate (2.5-60 mg/kg, s.c.) and ketamine (2.5-30 mg/kg, i.p.) given alone did not produce any effect on antinociception. However, there is a synergistic interaction between ketamine (2.5, 5 and 10 mg/kg) and magnesium sulfate (5 mg/kg). Both ketamine and magnesium sulfate, as well as their combination potentiated the antinociceptive effect of morphine (2.6 mg/kg, i.p.).
Conclusion: This study revealed potentiation of ketamine and morphine-ketamine combination by magnesium sulphate in tail-immersion test in rats with higher activity when ketamine is given before magnesium sulfate. It is first time to demonstrate the synergistic interaction between magnesium sulphate and ketamine in lowering body temperature and in antinociception with statistical confirmation.
25Mg2+-related magnetic isotope effect to misconduct the DNA repair system in cancer cells: new cytostatic approach
Maria A. Dryagina, Aleksander A. Bukhvostov, Vladimir P. Chekhonin, Dmitry A. Kuznetsov
Department of Medicinal Nanobiotechnologies, N. I. Pirogov Russian National Research Medical University, Ostrovityanov St.1, Moscow 117997, Russia
Human retinoblastoma (HRB) cells were proven to possess some very unusual DNApolβ species, 23.5 kDa catalytically active monomers. These chromatin associated proteins manifests most of the DNApolβ-specific functional peculiarities making them the legitimate targets for the DNA repair related cytostatic inhibitors. Two HRB cell lines, WERI-RB and Y79, were subjected for purification – characterization of these enzymes. This is a first report ever on this type of enzymes isolated from the HRB cell population. These enzymes are the low processivity “molecular machines” which is clearly reflected by kinetic constants: WERI-RB-1A, KM = 0.012 mM, Kcat = 0.609 (μM dTTP/min)/mg enzyme; Y79, KM = 0.018 mM, Kcat = 0.617 (μM dTTP/min)/mg enzyme. A high resistance to Aphidicolin and N-ethyl-melamide along with a marked sensitivity to ddTTP, which has been shown simultaneously with the 200 mM KCl – promoted hyperactivation are also the reliable taxonomic signs for the DNApolβ family members. A total lack of 3’,5’-exonuclease catalytic activity and, last not least, short size (not longer than 300 bp) of the DNA fragments produced by enzymes are highly specific diagnostic pattern indicating to the DNApolβ programmed catalysis.
Being Mg2+–dependent biocatalysts, these unique tumor – specific DNApolβ species were found suitable for a sharp decrease of catalytic activity once non-magnetic ions of 24Mg2+/26Mg2+ isotopes replaced with a paramagnetic 25Mg2+ isotope inside the enzyme catalytic site. This magnetic isotope effect is itself a promising sign of biochemical background for the novel chemotherapeutic approach consisting in 25Mg2+ administration as long as the ion-targeted DNApolβ engaged.
TRPM7 and MagT1 in colon carcinoma Lovo cells sensitive or resistant to doxorubicin
Alessandra Cazzaniga1, Claudia Moscheni1, Laura Locatelli1, Azzurra Sargenti2, Sara Castiglioni1
1 Dipartimento di Scienze Biomediche e Cliniche L. Sacco, Università di Milano, Milano I-20157, 2 Dipartimento di Farmacia e Biotecnologie, Università Alma Mater di Bologna, Via San Donato 19/2, Bologna I-40127, Italy
Purpose: Little is known about magnesium homeostasis and role in drug-resistant neoplastic cells. Therefore, we have compared the in vitro behavior of LoVo cells sensitive or resistant to doxorubicin (LoVo-S and LoVo-R, respectively). We have analyzed the expression of some magnesium transporters -TRPM6, TRPM7 and MagT1- and the intracellular content of total magnesium. We have also investigated whether these transporters play a role in regulating cell proliferation and sensitivity to doxorubicin.
Material and Methods: We performed Real-Time PCR and Western Blot to study the expression of TRPMs and MagT1 in LoVo-S and -R. We silenced TRPMs and MagT1 and evaluated cell proliferation by a cell counter and sensitivity to doxorubicin by MTT assay. Total Mg content was assessed using the fluorescent chemosensor DCHQ5.
Results: Total intracellular Mg was measured in sparse and confluent cells and found to be higher in LoVo-R than in LoVo-S. The amounts of TRPMs were higher in LoVo-S than in LoVo-R, while MagT1 expression was increased in LoVo-R. These differences were maintained in sparse and confluent cells. Silencing TRPM7 in LoVo-S and MagT1 in LoVo-R markedly retarded cell proliferation. Silencing TRPM7 also induced LoVo-S to shift their phenotype into a resistant one. In LoVo-R the calpain inhibitor calpeptin upregulated TRPM7, accelerated cell growth and induced the cells to become sensitive to doxorubicin. Silencing TRPM6 in LoVo-S does not affect cell proliferation and drug resistance.
Conclusion: TRPM7 and MagT1 contribute to cell proliferation. Moreover, the modulation of the expression of TRPM7 has an important role in drug-resistance.
PRL phosphatases in magnesium homeostasis and cancer
Serge Hardy1, Elie Kostantin1,2, Jeremy Gungabeesoon1,2, Yevgen Zolotarov1,2, Noriko Uetani1, Julie St-Pierre1,2, Luis Alfonso Martinez-Cruz3and Michel L. Tremblay1,2
1Rosalind and Morris Goodman Cancer Research Centre, Montréal, Canada, 2Department of Biochemistry, McGill University, Montréal, Canada, 3CIC bioGUNE, Bilbao, Spain
Purpose: The three Phosphatase of Regenerative Liver (PRL-1, -2, -3) enzymes have been identified as key contributors to tumor progression and metastasis in several human cancers, yet the molecular basis of their pro-oncogenic property is unclear. Our previous studies identified the CNNM magnesium transporters as key PRL binding partners in an evolutionarily conserved complex that regulates intracellular magnesium concentration. Still, the molecular basis of this protein complex and PRL physiological functions remain largely unknown.
Materials and Methods: Based on bioinformatic/structural analyses, we generated several recombinant CNNMs mutants to characterize the interaction with PRLs. Various biological assays including xenografts were performed in order to investigate the PRL/CNNM complex tumorigenic potential. In addition, the expression levels of these partners were determined followed by the modulation of extracellular magnesium levels. Finally, PRL-2 deficient mice were analyzed to understand its physiological function, and using a lacZ reporter mouse model, PRL-2 tissue expression patterns were characterized when changing dietary magnesium.
Results: Mutation of an evolutionarily conserved aspartic acid located in the second CBS domain of CNNM3 was able to completely abolish the interaction with PRL-2. Supporting the role of this complex in cancer progression, mutant CNNM3 overexpression reduced tumor growth. Also, either the abolishment of complex formation or PRL-2 knockdown resulted in reduced magnesium transport. We confirmed that mitochondrial respiration is altered in absence of PRL-2 and is associated with a lower ATP turnover. This is also consistent with the observed decreased body weight of PRL-2 -/- mice, suggesting that their cellular metabolism is inherently less efficient. Finally, we uncovered a PRL-2 expression pattern, which is dramatically deregulated by altered magnesium levels.
Conclusion: Our findings suggest that PRL phosphatases regulate cellular bioenergetics by providing magnesium for cell survival/proliferation, which may explain much of the clinical relationship between PRLs and cancer.
Expression and activities of magnesium-specific ion channels in colon carcinoma cells
1Istituto di Patologia Generale, Facoltà di Medicina e Chirurgia “A. Gemelli”, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168 Rome, Italy, 2University of Picardie Jules Verne, UFR Sciences, Laboratory of Cell and Molecular Physiology, Amiens, France
Purpose: Cellular magnesium homeostasis is regulated by the combined action of several ion channels. In particular it is known that the Transient Receptor Potential Melastatin TRPM7 channel influences the behavior of cancer cells by modulating proliferation, migration and invasiveness. The homologous TRPM6 channel is responsible for Mg absorption in the colon and in the kidney distal convoluted tubule. We investigated the expression of TRPM7 and TRPM6 channels in colon cancer cells, and we assessed their effects in relation to parameters relevant to tumor development, namely proliferation and migration.
Materials and Methods: We used HCT116 and HT29 colon carcinoma cell lines. The expression of TRPM6 and TRPM7 was evaluated by RT-PCR and Western Blotting. Cell proliferation was assessed by MTT assay and cell migration by scratch assay. TRPM7 expression was silenced by RNA interference. Intracellular influx of cationic species was evaluated by Mn2+ quenching using the fluorescent probe Fura-2.
Results: Both cell lines express TRPM7 and TRPM6. However the effects of TRPM7 on proliferation and migration are unusual. While in HT29 silencing of TRPM7 seems not to affect proliferation and migration, in HCT116 we observed an increase in cell proliferation and migration upon TRPM7 silencing. Correspondingly, silenced HCT116 cells show an increased cation influx compared to control cells.
Conclusion: We found that expression of TRPM7 is inversely correlated with cell proliferation and migration in colon carcinoma HCT116 cells, but not in HT29 cells. This results are in contrast with what is reported in the literature for all types of cancer cells studied so far. The different behavior of HCT116 and HT29 could represent an useful research tool to investigate the underlying molecular mechanisms. This approach could help in the understanding the potential diagnostic and/or therapeutic applications of these ion channels.
1 N ATAMag®: Mg2+ 93,75 mg as MgO; ATAMg®; Vit B1: 0.55 mg; vit B2/B6: 0.7 mg; taurine:100 mg; L-Thréonine/glucine 50 mg for 2 caps/day