ARTICLE
Auteur(s) : Masahiko Toyoda1,2, Motokazu
Nakamura1, Hidemi
Nakagawa2
1Department of Dermatology, Faculty of Medicine,
Toyama University, 2630 Sugitani, Toyama 930-0194, Japan
2Department of Dermatology, Jikei University School of
Medicine, 3-19-18 Nishishinbashi, Minato-ku, Tokyo 105-8471,
Japan
accepté le 14 Octobre 2006
Histamine is a fundamental mediator released from tissue mast cells
during the immediate allergic response [1] and chiefly from
recruited basophils during the late-phase response [2]. It is
considered to be one of the most potent inducers of pruritus.
Histamine H1-receptor antagonists (antihistamines)
relieve symptoms in skin disorders in which histamine is the major
chemical mediator of inflammation [1]. They act primarily at
H1-receptors on the post-capillary venules in the skin
to prevent histamine-induced vasodilatation, increased vascular
permeability, and wheal reactions [3]. They also act through a
neurogenic reflex to prevent histamine-induced erythema (flaring)
[3] and at the H1-receptors on small, extensively
branching, unmyelinated C-fibers in the skin to prevent pruritus
[4]. In addition, many antihistamines have an anti-allergic and
anti-inflammatory activity in skin [5]. Therefore these agents are
frequently used for the treatment of cutaneous pruritic diseases
such as atopic dermatitis (AD), in which mast cells and released
histamine play significant roles [6]. Epinastine hydrochloride is a
second-generation histamine H1-receptor antagonist
commonly used in Japan with good clinical results [7]. Epinastine
hydrochloride exhibits potent inhibitory action on not only the
H1-receptor but also on inflammatory mediator release
from mast cells, following its systemic administration [8, 9]. In
addition to its antihistaminic effect, several studies have
demonstrated that epinastine hydrochloride exerts a variety of
unique pharmacological modes of action [10-13].Much remains unknown
about the pathogenesis, etiology, and mechanism responsible for
pruritus in AD, although one major symptom of AD patients is
pruritus. The involvement of unmyelinated, histamine-sensitive
nerve fibers has been established for experimental pruritus, and
“itch-specific” C-fibers have also been identified [4]. In
addition, an increase in the number of activating mast cells within
the upper dermis and the presence of mast cells within the
epidermis are characteristically observed in the skin of AD
patients [14]. Thus interactions between the peripheral nerves and
mast cells should contribute, in part, to the vicious circle of
pruritus, scratching, and worsening of eczema, with subsequently
intensified pruritus and the induction of neurogenic inflammation
in the skin of AD patients. Since antihistamines such as epinastine
possess an anti-pruritic effect, they have been a standard therapy
in AD and recommended in many clinical treatment protocols,
together with topical treatment regimens such as corticosteroids.It
is of considerable interest to know the concentrations of
antihistamines in the skin since knowledge about the relationship
between the drug levels of antihistamines in the skin and the
clinical pharmacological effect is important for a rational drug
therapy of AD pruritus. A method that allows measurement of the
tissue concentration of either topically or systemically
administered drugs is the suction blister technique [15]. The
suction blister fluid corresponds roughly to average interstitial
fluid [16] and has been used and validated in several
pharmacokinetic experiments [17, 18]. The method has been
successfully used to study the concentration profile of
pharmacologically active compounds or inflammatory mediators [15].
In this study, the suction blister technique was therefore applied
to the measurement of extracellular concentrations of epinastine
hydrochloride in comparison with chlorpheniramine maleate, a
first-generation antihistamine, in the skin of AD patients. This is
the first attempt to measure in vivo drug levels of antihistamines
in the skin from AD patients.
Materials and methods
A total of 79 patients (48 males, 31 females; mean age, 28.6
[range, 18-42] years) with a confirmed diagnosis of AD according to
the criteria of Hanifin and Rajka [19] were enrolled in this study.
These AD patients had not received any topical treatment for ≥1
week prior to the study or systemic treatment for 1 month prior to
the study. None of the subjects had any other concomitant
dermatological or medical disorders. This study was conducted
according to the ethical standards of Toyama University, which
require informed consent from each subject. The patients were
randomly allocated to receive either 20 mg of epinastine
hydrochloride (Alesion, Boehringer Ingerheim Co, Ltd, Japan) orally
or 6 mg of chlorpheniramine maleate (Polaramine, Schering-Plough
KK, Japan) orally in an open trial design. No adjunct therapies
were used in any of the patients enrolled, except for the use of
moisturizing cream on the upper arms. As a result, patients were
put on courses of daily medication for 7-126 (mean, 45.7) and 5-154
(mean, 41.6) days of epinastine and chlorpheniramine, respectively.
Epinastine was given to 42 patients (24 males, 18 females; mean age
29 [range, 18-38] years), and chlorpheniramine was given to 37
patients (24 males, 13 females; mean age, 27.3 [range, 20-42]
years). Suction blisters were induced on the volar aspect of both
upper arms by disposable syringes as previously described [20, 21]
in all patients. On each upper arm 7-mm blisters were provoked
within 60 minutes. On the last day of the medication, suction
blister fluid was obtained at 1-22 and 1-12 hours after the final
administration of epinastine and chlorpheniramine, respectively.
Blister fluid was collected by syringe, cooled with ice, and
rapidly frozen to – 70 °C until assay for drug
concentrations.
Concentrations of epinastine hydrochloride and chlorpheniramine
maleate in suction blister fluid were determined by liquid
chromatography-tandem mass spectrometry (LC-MS/MS). LC-MS/MS
analysis was performed by HPLC Agilent 1100 system liquid
chromatograph (Agilent Technologies) coupled to a TSQ 7000 mass
spectrometer (ThermoQuest). Diphenidol hydrochloride and
(±)-brompheniramine maleate were used as an internal standard for
epinastine hydrochloride and chlorpheniramine maleate,
respectively. Calibration standard solutions were prepared using
human plasma instead of human transudate.
Quantitative determination of epinastine hydrochloride was
performed by HPLC according to the method of Ohtani et al. [22].
Chlorpheniramine concentrations were evaluated according to the
method of Celma [23].
The degree of pruritus was evaluated using a verbal ten-point
pruritic scale (VTPS) [24] before and after administration of each
drug and on the day of the examination.
Results
At baseline, the degree of pruritus as evaluated by VTPS in
patients receiving epinastine and chlorpheniramine was 33.2 ± 5.3
and 31.6 ± 6.0, respectively. On the other hand, after treatment,
VTPS was 7.6 ± 1.9 and 26.3 ± 8.4 in the two groups, respectively.
While there was a statistically significant (P < 0.001) decrease
of VTPS in the epinastine group, no statistically significant
change of VTPS was found in the chlorpheniramine group (paired
Student t-test) ( (figure 1) ).
Epinastine hydrochloride concentrations in 42 samples were
5.02-33.07 ng/mL (mean ± SD, 14.08 ± 10.51; median, 7.00). While
there was no significant correlation between ingestion periods and
epinastine hydrochloride concentrations, a statistically-negative
correlation was observed between the time of internal use and
concentration (( figure
2 ); correlation coefficient = 0.774, P < 0.005). In
contrast, chlorpheniramine maleate concentrations in all 37 samples
were below the lower limit of quantification (< 0.5
ng/mL).
Discussion
For oral medicine to be effective in skin, it is necessary for
active metabolites to shift from blood vessels to skin compartments
in sufficiently high concentrations. Antihistamines act as inverse
agonists at the H1-receptors and therefore must be
present in the skin in sufficiently large quantities to compete
with histamine for occupying the receptors and, in that way,
prevent the histamine released during an allergic reaction from
combining with the H1-receptors and causing symptoms.
The present study demonstrated that the antihistamine epinastine
hydrochloride is distributed in high concentrations into the skin,
equal to levels found in plasma (Cmax, 34.11 ± 12.56 ng/mL) [25].
This suggests that epinastine is likely to be more effective
clinically than chlorpheniramine in AD, which was not detected in
the skin from AD patients. Indeed a significant decrease in the
degree of pruritus was observed only in the AD patients
administered epinastine. In contrast with epinastine,
chlorpheniramine may not reach the skin but may act centrally more
or less to dampen pruritus in AD patients. Our clinical data
support a randomized, double-blind, placebo-controlled study [26]
in which chlorpheniramine was shown to be ineffective for pruritus
in AD patients. In turn we need large, randomized, double-blinded
studies to confirm the strongly suppressive effect of epinastine on
pruritus in AD patients as suggested in the present open trial
design.
The study design, i.e. using skin biopsies to measure
antihistamine concentrations in the skin [27, 28], did not permit
us to ascertain whether the H1-receptor antagonists
detected in skin were located in extracellular fluid, were bound to
H1-receptors, or were at both sites. Attempts by
microdialysis techniques over 4 hours after a single oral dose to
delineate the concentrations of another antihistamine, cetirizine,
in the skin extracellular water compartment, suggested that the
antihistamine concentrations in skin dialysate are extremely low;
i.e. skin levels were < 1/100 of plasma concentrations [29].
This is mainly due to the methodological limitations of measuring
drug levels. Although extracellular concentrations should be
determined as the total protein- and non-protein-bound
antihistamine fractions, the microdialysis technique allows only
the non-protein-bound fraction to diffuse across the dialysis
membrane, and cetirizine is a highly protein-bound drug in vivo
[29]. On the other hand, we obtained the total fractions of
protein- and non-protein-bound epinastine in the extracellular
fluid of the skin by using the suction blister technique. The
epinastine concentrations achieved in this study were within the
range of epinastine concentrations used in some in vitro studies of
its anti-allergic and anti-inflammatory effects [8-13] and the
daily dose of epinastine was the same as that of in vivo studies of
long-lasting inhibitory effects on histamine-induced skin tests
[30, 31]. The results of the present study suggest that epinastine
is readily able to enter skin and its high concentrations in skin
may contribute to its well-known efficacy against cutaneous
pruritic diseases, in which histamine plays a role. However,
consideration must also be given here to the technical limitations
of measuring drug levels by use of suction blister fluid,
especially when drug levels in the skin are compared with those
using different methods, such as skin biopsies. Although the
suction blister fluid corresponds roughly to average interstitial
fluid [16], the possibility cannot be excluded that the procedure
of generating the blister may favor the accumulation of the drug in
the blister fluid. In addition, this study was not planned as a
pharmacodynamic investigation in AD and correlation of drug levels
with inhibition of histamine-induced skin responses was not
examined as in the previously published studies using intact human
skin [27-29].
Altered patterns of cutaneous innervation have been reported in
many inflammatory dermatoses such as AD, where an increased
presence of nerve fibers is histologically characterized in the
superficial dermis as well as in the epidermis, in lesional and
non-lesional skin (atopic dry skin) [32-34]. This suggests that AD
patients may be more vulnerable to intrinsic and extrinsic stimuli
following stimulation of C-fibers and hyperinnervation in the skin
of AD patients may result in a lower itch threshold and intensely
pruritic conditions. Stimulation of C-fibers can provoke the
release of neuropeptides such as substance P (SP) from peripheral
nerve terminals by axon reflex [35]. SP is generally believed to
elicit pruritus through release of histamine from mast cells. In
human subjects, H1-receptor antagonists inhibit the itch
sensation induced by intradermal injection of low-dose SP [36].
Intradermal injection of SP elicits itch-associated responses in
normal as well as in mast cell-deficient mice [37]. The
neurokinin-1 tachykinin receptor, the main receptor of SP, is
involved in the itch-associated response induced by SP, but not in
histamine release from mast cells [35]. These findings suggest that
both mast cell-dependent and -independent mechanisms are involved
in SP-induced itch-associated responses [35]. We recently reported
epinastine concentration-dependent decreases of the percentage of
cultured murine dorsal root ganglion with outgrowing neuritis,
total number of neuritis, average extension length of neuritis, and
capsaicin-induced SP release in vitro [13]. Taking into account
increases in the population of mast cells in the skin, as well as
in histamine levels in the plasma from AD patients, rich
innervation [32-34], and high concentrations of epinastine in the
skin extracellular water compartment, epinastine may exert an
anti-pruritic activity by inhibiting sensory neurons as well as by
the suppression of SP release from nerve terminals, in addition to
its potent H1-receptor antagonistic effects. Since human
skin mast cells can release SP, AD skin has increased numbers of
SP-containing mast cells [38], and SP induces mast cells to
degranulate in vitro [39]. Inhibiting the release of inflammatory
mediators, including SP, from mast cells may also, in part, explain
epinastine’s clinical efficacy against pruritic skin diseases such
as AD.
In conclusion, through our experiment, the high epidermal spread
characteristics of epinastine hydrochloride in AD were confirmed,
although it is not yet certain whether such a pharmacodynamic
profile is specific to epinastine among the second-generation
antihistamines. However, this is an extremely important finding
since epinastine readily diffuses from the systemic circulation
into the extracellular water phase in inflammatory lesions and may
have a direct inhibitory effect on the mechanism of pruritus in the
skin of AD patients.
Acknowledgement of funding and grants
This study was supported by Nippon Boehringer Ingelheim KK.
References
1 Simons FER, Simons KJ. The pharmacology and use of
H1-receptor antagonist drugs. N Engl J Med 1994; 330:
1663-70.
2 Grant JA, Li H. Biology of basophils. In:
Adkinson NF, Busse WW, eds. Allergy: Principles and
Practice. 5th ed. St. Louis: Mosby, 1998: 277-84.
3 Petersen LJ, Church MK, Skov PS. Histamine is
released in the wheal but not flare following challenge of human
skin in vivo: a microdialysis study. Clin Exp Allergy 1997; 27:
284-95.
4 Schmelz M, Schmidt R, Bickel A,
Handwerker HO, Torebjork HE. Specific C-receptors for
itch in human skin. J Neurosci 1997; 17: 8003-8.
5 Church MK. Non-H1-receptor effects of
antihistamines. Clin Exp Allergy 1999; 29(Suppl 3): 39-48.
6 Van Bever HP. Recent advances in the pathogenesis of
atopic dermatitis. Eur J Pediatr 1992; 151: 870-3.
7 Makino S. Use of antiallergic drugs in Japan. ACI NEWs
1995; 7: 165-7.
8 Amon U, Gibbs BF, Buss G, Nitschke M. In
vivo investigations with the histamine H1 receptor
antagonist, epinastine (WAL 801 CL), on isolated human allergic
effector cells. Inflamm Res 2000; 49: 112-6.
9 Kamei C, Akagi M, Mio M, Kitazumi K,
Izushi K, Masaki S, Tasaka K. Antiallergic effect of
epinastine (WAL 801 CL) on immediate hypersensitivity reactions:
elucidation of the mechanism for histamine release inhibition.
Immunopharm Immunotoxicol 1992; 14: 191-205.
10 Fukuishi N, Kan T, Hirose K, Akagi R,
Akagi M. Inhibitory effect of epinastine on superoxide
generation by rat neutrophils. Jpn J Pharmacol 1995; 68:
449-52.
11 Kohyama T, Takizawa H, Akiyama N, Sato M,
Kawasaki S, Ito K. A novel antiallergic drug epinastine
inhibits IL-8 release from human eosinophils. Biochem Biophys Res
Commun 1977; 230: 125-8.
12 Nakagawa T, Kakinuma Y, Akitaya T,
Shimada J, Mizushima Y. Modulatory effects of epinastine
hydrochloride on IL-4 mRNA expression by peripheral blood
mononuclear cells. Int Arch Allergy Immunol 1977; 113: 321-2.
13 Toyoda M, Nakamura M, Nakada K, Iida M,
Nakamura M, Otani M, Etoh T, Nakagawa H,
Morohashi M. Effect of epinastine hydrochloride, a
second-generation histamine H1-receptor antagonist, on
sensory neurons in vitro. Allergol Int 2005; 4: 565-72.
14 Imayama S, Shibata Y, Hori Y. Epidermal mast
cells in atopic dermatitis. Lancet 1995; 346: 1559.
15 Kiistala U. Suction blister device for separation of
viable epidermis from dermis. J Invest Dermatol 1968; 50:
129-37.
16 Rossing N. Worm AM-Interstitial fluid: Exchange of
macromolecules between plasma and skin interstitum. Clin Physiol
1981; 1: 275-84.
17 Borg N, Gotharson E, Benfeldt E, Groth L,
Stahle L. Distribution to the skin of penciclovir after oral
famciclovir administration in healthy volunteers: Comparison of
suction blister technique and cutaneous microdialysis. Acta Derm
Venereol 1999; 79: 274-7.
18 Benfeldt E, Serup J, Menne T. Microdialysis
vs. suction blister technique for in vivo sampling of
pharmacokinetics in the human dermis. Acta Derm Venereol 1999; 79:
338-42.
19 Hanifin JM, Rajka G. Diagnostic features of atopic
dermatitis. Acta Derm Venereol (Stockh) 1980(Suppl 92): 44-7.
20 Horikawa T, Mishima Y, Nishino K,
Ichihashi M. Horizontal and vertical pigment spread into
surrounding piebald epidermis and hair follicles after suction
blister epidermal grafting. Pigment Cell Res 1999; 12: 175-80.
21 Koga M. Epidermal grafting using the tops of suction
blisters in the treatment of vitiligo. Arch Dermatol 1988; 124:
1656-8.
22 Ohtani H, Kotaki H, Sawada Y, Iga T.
Quantitative determination of epinastine in plasma by
high-performance liquid chromatography. J Chromatogr B 1996; 683:
281-4.
23 Celma C, Allue JA, Prunonosa J,
Peraire C, Obach R. Simultaneous determination of
paracetamol and chlorpheniramine in human plasma by liquid
chromatography-tandem mass spectrometry. J Chromatogr A 2000;
870(1-2): 77-86.
24 Nakamura M, Toyoda M, Morohashi M.
Pruritogenic mediators in psoriasis vulgaris: comparative
evaluation of itch-associated cutaneous factors. Br J Dermatol
2003; 149: 718-30.
25 Azuma J, Yoshida H, Seto Y, Fukui K,
Konishi K, Otani M, Tarui S, Nagakura A,
Kohei H. Phase-1 study of WAL801CL tablet (in Japanese). J
Clin Ther Med 1992; 8(Suppl 1): 3-24.
26 Munday J, Bloomfield R, Goldman M,
Robey H, Kitowska GJ, Gwiezdziski Z,
Wankiewicz A, Marks R, Protas-Drozd F,
Mikaszewska M. Chlorpheniramine is not more effective than
placebo in relieving the symptoms of childhood atopic dermatitis
with a nocturnal itching and scratching component. Dermatology
2002; 205: 40-5.
27 Simons FER, Murray HE, Simons KJ. Quantitation
of H1-receptor antagonists in skin and serum. J Allergy
Clin Immunol 1995; 95: 759-64.
28 Simons FER, Silver NA, Gu X, Simons KJ.
Skin concentrations of H1-receptor antagonists. J
Allergy Clin Immunol 2001; 107: 526-30.
29 Petersen LJ, Church MK, Rihoux J-P,
Skov PS. Measurement of interstitial cetirizine concentrations
in human skin: correlation of drug levels with inhibition of
histamine-induced skin responses. Allergy 1999; 54: 607-11.
30 Furue M, Terao H, Koga T. Effects of
cetirizine and epinastine on the skin response to histamine
iontophoresis. J Dermatol Sci 2001; 25: 59-63.
31 Grant JA, Danielson L, Rihoux J-P,
DeVos C. A double-blind, single-dose, crossover comparison of
cetirizine, ebastine, epinastine, fexofenadine, terfenadine,
and loratadine versus placebo: suppression of histamine-induced
wheal and flare response for 24h in healthy male subjects. Allergy
1999; 54: 700-7.
32 Leung DYA, Rhodes AR, Geha RS,
Schneider L, Ring J. Atopic dermatitis (atopic eczema).
In: Fitzpatrick TB, Eisen AZ, Wolff K,
Freedberg IM, Austen KF, eds. Dermatology in General
Medicine. 4th ed. New York: McGraw-Hill, 1993: 1543-64.
33 Tobin D, Nabarro G, de la Faille HB, van
Vloten WA, van der Putte SC, Schuurman HJ. Increased
number of immunoreactive nerve fibers in atopic dermatitis. J
Allergy Clin Immunol 1995; 90: 613-22.
34 Toyoda M, Morimatsu S, Morohashi M. The
alterations of cutaneous innervation and neuropeptide expression by
cyclosporine A treatment in atopic dermatitis: an
immunohistochemical study (in Japanese). Jpn J Dermatol 1997; 107:
1275-9.
35 Scholzen T, Armstrong CA, Bunnett NW,
Luger TA, Olerud JE, Ansel JC. Neuropeptides in the
skin: interactions between the neuroendocrine and the skin immune
system. Exp Dermatol 1998; 7: 81-96.
36 Hagermark O, Hokfelt T, Pernow B. Flare and
itch induced by substance P in human skin. J Invest Dermatol 1977;
57: 37-43.
37 Andoh T, Nagasawa T, Satoh M, Kuraishi Y.
Substance P induction of itch-associated response mediated by
cutaneous NK1 tachykinin receptors in mice. J Pharmacol Exp Ther
1998; 286: 1140-5.
38 Toyoda M, Makino T, Kagoura M,
Morohashi M. Immunolocalization of substance P in human skin
mast cells. Arch Dermatol Res 2000; 292: 418-21.
39 Stead RH, Bienenstock J, Stanisz AM.
Neuropeptide regulation of mucosal immunity. Immunol Rev 1987; 10:
333-59.
|
Printable version
Version PDF
