Oral communication, CS22 / C109

Official XXIst International Pigment Cell Conference website - 21-24 Sept 2011, Bordeaux - France | updated: September 04 2011

The paradox of the effects of PGF2alpha on pigmentation in vivo and in vitro

SPEAKER T. Anbar #whois submiter ?
AUTHOR(s) T.S. Anbar, D. Kendall, H. Abdel-Raouf, T.S. El-Ammawi, M. Barakat, A.T. Abdel-Rahman, R. Torky, A. Fawzy, M. Hanna

In a laboratory study we used cultured immortalized human melanocytes (Hermes-2B) to study the effects of prostaglandin (PG)E2 and PGF2alpha on melanin content and ERK1/2 activation, which is belongs to MAPK family responsible for proliferation, differentiation, cell survival and apoptosis, using Western immune-blotting. Since cAMP is known to be involved in melanin synthesis, the acute effects of the drugs on cAMP formation in the cells were assessed using a [3H]-adenine pre-labelling assay. It was found that both prostaglandins induced a significant activation of the ERK1/2, however only PGE2, but not PGF2alpha, increased the melanin content. Neither PGE2 nor PGF2alpha increased intracellular cAMP accumulation. On the other hand, in an animal study using 18 female adult wild Guinea pigs we evaluated the effects of three PGF2alpha analogues on skin pigmentation in comparison to NB-UVB both clinically and histopathologically. All three PGF2α analogues were found to increase skin pigmentation at the site of application to a degree comparable with that of NB-UVB. Moreover, in a recent study we evaluated the efficacy of topical Latanoprost, PGF2alpha analogue, in induction of skin re-pigmentation in 22 stable non- segmental vitiligo patients and compared its potency with NB-UVB. It was found that Latanoprost induced a significantly better skin re-pigmentation compared with placebo. This pigmentation was similar to that obtained after NB-UVB exposure. From all the above obtained results, we are wondering if the enhancement of dendricity and maturation induced by PG F2alpha in vitro is enough to explain its effect on induction of pigmentation, in animal model and vitiligo patients, or there are other mechanisms related to the nearby keratinocytes or growth factors that may play a role, a question waiting to be answered.



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Université de Bordeaux 2 & Conseil Régional Aquitaine