Abstracts of Journal of Japanese Society for Magnesium Research Volume 24, Number 1, 2005

ARTICLE

The effect of vitamin K2 (MK-4) on reduced “bone quality” by magnesium insufficiency

Divisions of ¹ Oral Anatomy, Niigata University Graduate School of Medical and Dental Sciences,
² Center for Transdisciplinary Research, Niigata University Niigata Japan
³ Pharmacological Evaluation Section, Department of Drug Research II, Eisai. Co. Ltd., Tokyo, Japan
⁴ Institute for Dental Science, Matsumoto Dental University, Shiojiri, Japan

Mg-insufficient bone reveals fragility to mechanical loading despite normal or higher levels of bone mineral content (Kobayashi et al., Bone 2004: 35; 1136). The administration with vitamin K2 (MK-4: menatetrenone), however, inhibited the reduced maximum load and elastic modulus of the Mg-insufficient bone, indicating that MK-4 increased the “bone quality”. Therefore, we have examined bone remodeling and mineral of the tibiae and femora of 4-week-old Wistar male rats fed normal (control group, 0.09% Mg), Mg-insufficient (low Mg group, 0.006% Mg), or MK-4 supplemented Mg-insufficient diets (MK-4 group, 30 mg/kg MK-4, 0.006% Mg) for 4-, or 8-weeks. The termini of the shortened metaphyseal trabeculae of low Mg groups localized many osteoclasts with well-developed ruffled borders. In addition, the Mg-insufficient cortical bones showed complicated meshwork of cement lines, implying accelerated bone remodeling. In contrast, the MK-4 groups showed osteoclasts with poorly-formed ruffled borders on metaphyseal trabeculae, and fewer numbers of cement lines in the cortical bone. Thus, MK-4 appeared to inhibit osteoclastic bone resorption once stimulated by Mg-insufficiency, thereby normalizing bone remodeling. An electron probe microanalyzer (EPMA) demonstrated an increased and decreased concentrations of Ca and Mg in the low Mg group, respectively. X-ray diffraction provided various chemical formulae of mineralized crystals including hydroxyapatites (HA) in the control group, but an extremely-elevated purity of HA [Cai0(P04)6(OH)2] in the low Mg group. Consistently, Mg-insufficient bone showed large mineralized nodules and premature mineralization of collagen fîbrils in the osteoid. Therefore, an increased concentration of Ca in the Mg-insufficient bone may cause the high purity of HA, larger mineralized nodules and premature collagenous mineralization. In contrast, MK-4 did not affect the concentration of Mg and Ca, or HA-purity, but prevented mineralization accelerated by Mg-insuffîciency. Thus, MK-4 appears to recover the “bone quality” lessened by Mg insufficiency by two mechanisms: controlling bone turnover and mineralization.

Key words :  magnesium, vitamin K2 (MK-4: menatetrenone), bone, bone quality, histology

The relationships between markers of either bone resorption or bone formation and serum magnesium or calcium levels

Noboru Saito¹, Yoshihisa Ando², Naoto Tabata², Saburou Saito¹, Shoji Nishiyama³

¹ Department of Internal Medicine and Center for lifestyle-related Diseases
² Department of Surgery and Center for Alimentary Tract and Liver Diseases
³ Miyazaki Medical Center Hospital, Department of Hygiene, Faculty of Medicine, Showa University

This study is aimed to clarify the relationships between bone resorption or formation markers and serum magnesium (Mg) or calcium (Ca) levels in elderly inpatients. In this study 107 inpatients (33 males, 74 females) were recruited, who did not take furosemide, spironolactone, alfacalcidol and magnesium oxide, and who showed below 30 mg/dL of BUN to exclude cases with renal failure. Fasting blood samples and urinary samples were obtained early in the morning. Markers of bone resorption such as urinary deoxypyridinoline (DPd) and N-telopeptide (NTx) were measured by ELISA, which were divided by urinary creatinine (Cr) and expressed as DPd/cr and NTx/cr. As a bone formation marker serum osteocalcin (OC) was measured by IRMA. Serum Mg was measured by xylizil blue method, and Ca was measured by OCPC.
Urinary DPd/cr and NTx/cr tended to increase by aging, but not significantly. In elderly inpatients aged 65 to 79 years old, 10 males over 60 nMBCE/mM/cr of NTx/cr showed a high level of DPd/cr and lower levels of serum Mg, Ca, zinc (Zn), total protein (TP) and albumin (Alb) compared to 8 males below it, while 21 females over it did a high level of DPd/cr and a lower level of serum Ca compared to 12 females below it.
Therefore, urinary NTx/cr and DPd/cr were inversely related to serum Mg, Ca, Zn, TP and Alb in males, while these were inversely related only to serum Ca in females.

Key words : deoxypyridinoline, N-telopeptide, osteocalcin, serum magnesium, serum calcium

Magnesium and other mineral levels in blood of middle age Japanese men and women

R Takeda^{1, 3}, T. Nakamura¹, T. Suyama², Y. Minakuchi², M. Ishida³, M. Imanishi³, H. Shigetomi³, A. Takeda³, R. Kitamura², T. Takeda³, M. Kimura³

¹ Graduate School of Medicine, Kyoto University
² Takeda Hospital Health Center
³ Takeda Research Institute of Life Science
<kimura@takedahp.or.jp>

To clarify mineral nutritional status, 424 men (46.3 ± 8.2 years) and 274 women (45.7 ± 8.7 years), total 698 inhabitants living in Kyoto and Shiga prefectures in Japan were selected for volunteers as healthy subjects (have no disease) with informed consent. Magnesium (Mg), calcium (Ca), sulfur (S), iron (Fe), phosphorus (P), zinc (Zn) and copper (Cu) concentrations in blood after wet digestion by nitric acid were determined by inductively coupled plasma-atomic emission spectrometry (OPTIMA4300DV: Perkin-Elmer Co. Ltd., USA). Blood mineral levels were as follows (average ± SD): Mg(μg/mL): 37.4 ± 3.2, Ca (μg/mL): 57.9  ± 3.8, S(mg/mL): 1.56 ± 0.11, Fe(μg/mL): 520 ± 38, P(μg/mL): 393 ± 32, Zn(μg/mL): 6.67 ± 0.78, Cu(ng/mL): 779 ± 93 in men and Mg(μg/mL): 34.6 ± 3.2, Ca(μg/mL): 62.5 ± 3.8, S(mg/mL): 1.47 ± 0.11, Fe(μg/mL): 442 ± 46, P(μg/mL): 367 ± 31, Zn(μg/mL): 5.84 ± 0.74, Cu(ng/mL): 837 ± 119 in women. Mg, S, Fe, P and Zn concentrations in blood of men were significantly high compared to that of women, and Ca and Cu concentrations in men were low compared to that of women.

Key words : human, magnesium, calcium, phosphorus, zinc

Stimulatory effect of fructooligosaccharides on intestinal magnesium absorption

Atsutane Ohta

Laboratory of Applied Nutrition, Faculty of Clinical Pharmaceutical Science, Division of Pharmaceutical Science, Josai International University

The Japanese Recommended Daily Allowance (Sixth revision) for magnesium has been established at 300 mg/day. However, there is little information about the dietary magnesium intake of Japanese. Several reports showed that Japanese dietary magnesium intake is about 200 to 250 mg/day. Thus, Japanese magnesium intake seems to be insufficient. Therefore, it is important that intestinal absorption of magnesium be increased in Japanese. Generally, about 35 to 70% of dietary magnesium is absorbed in the intestine. Intestinal magnesium absorption is believed to occur primarily in the ileum. However, several reports have revealed that magnesium absorption takes place not only via the small intestine, but also via the large intestine. The contribution of each intestinal segment to magnesium absorption remains unclear.
It has been reported that several nutrients inhibit intestinal magnesium absorption. Excess dietary calcium and phosphorus inhibit magnesium absorption by forming insoluble compounds with magnesium in the intestine. Many researchers confirmed that nondigestible carbohydrates such as fructooligosaccharides and resistant starch stimulate intestinal magnesium absorption in rats, and speculated that these stimulatory effects of nondigestible carbohydrates take place via the large intestine. Recently, several classical balance studies and the stable isotope method confirmed that nondigestible carbohydrates stimulate intestinal magnesium absorption in humans. Nutritional function of magnesium is very important, because magnesium is essential for over 300 enzymatic reactions in the human body. Future studies should be conducted to clarify the health benefits of the stimulatory effect of nondigestible carbohydrates on intestinal magnesium absorption.

Key words : magnesium, fructooligosaccharides, nondigestible carbohydrate, absorption, large intestine