Comedolytic effect of topically applied active vitamin D3 analogue on pseudocomedones in the rhino mouse.
BACKGROUND
Retinoids and active vitamin D(3) analogues regulate the proliferation and differentiation of keratinocytes and are effective in the treatment of psoriasis. Retinoids are known to be effective against acne vulgaris through comedolysis. However, the comedolytic effect of active vitamin D(3) analogues has not been reported.


OBJECTIVE
To investigate whether maxacalcitol, one of the active vitamin D(3) analogues, has a comedolytic effect by using spontaneously comedogenic rhino mice.


METHODS
Rhino mice were treated topically with tretinoin and maxacalcitol once daily for 2 and 4 weeks, respectively. The dermal side of the epidermal sheet was observed to determine the size of the utricle. Haematoxylin and eosin-stained vertical sections were used to measure utricle diameter and density and to evaluate histological changes.


RESULTS
Maxacalcitol (25 microg g(-1)) and tretinoin (0.1%) significantly decreased the size and the diameter of the utricle after 1 week of treatment. However, maxacalcitol did not affect the density while tretinoin did have an effect. Histopathologically, maxacalcitol and tretinoin markedly induced epidermal hyperplasia accompanied by a minor accumulation of inflammatory cells in the dermis, with and without hypercornification, respectively.


CONCLUSIONS
These results indicate that maxacalcitol has a prominent effect on comedolysis and that its mechanism of action may be different from that of retinoids.
Hayashi
N
N
Research Laboratories, Kyoto R&D Center, Maruho Co., Ltd, Chudoji, Kyoto 600-8815, Japan. hayashi@derm.twmu.ac.jp
Watanabe
H
H
Yasukawa
H
H
Uratsuji
H
H
Kanazawa
H
H
Ishimaru
M
M
Kotera
N
N
Akatsuka
M
M
Kawashima
M
M
D000152:Acne Vulgaris / Q000188:drug therapy* / Q000473:pathology; D000818:Animals; D002117:Calcitriol / Q000031:analogs & derivatives* / Q000627:therapeutic use; D003879:Dermatologic Agents / Q000627:therapeutic use*; D004817:Epidermis / Q000473:pathology; D051379:Mice; D008812:Mice, Hairless; D009824:Ointments; D016896:Treatment Outcome
D003879:Dermatologic Agents; D009824:Ointments; D002117:Calcitriol; C051883:maxacalcitol