Overexpression of proapoptotic proteins, Fas, and Bax after topical calcipotriol therapy for psoriasis

Background Suppression of the normal apoptotic process is one of the factors implicated in the pathogenesis of psoriasis. One of the actions of calcipotriol in psoriasis might be exerted through induction of apoptosis of keratinocytes through a p53-independent pathway. Objective The aim of the present study was to evaluate the expression of both Bax and Fas with its correlation with the apoptotic index and epidermal thickness in psoriatic skin before and at the end of the 8th week of topical calcipotriol therapy. Methods Lesional and nonlesional skin biopsy specimens were obtained from 10 patients with generalized plaque psoriasis. Histometric measurements of epidermal thickness were determined and Fas and Bax expressions were also evaluated using the immunoperoxidase technique and apoptotic cells using the terminal deoxynucleotide transferase-mediated deoxyuridine triphosphate nick end labeling method before and at the end of the 8th week of topical calcipotriol therapy. Results At the end of the 8th week of topical calcipotriol therapy, the epidermal thickness of psoriatic skin was significantly decreased (Po0.05) and a significant increase in both Fas and Bax expression (Po0.05) in psoriatic keratinocytes was observed, with no significant increase of either in lymphocytes (P40.05). Meanwhile, the apoptotic index was significantly increased in psoriatic keratinocytes (Po0.05), but not in lymphocytes (P40.05). However, there were no statistically significant correlations between proapoptotic markers (Fas and Bax) with either the apoptotic index or the epidermal thickness both before and at the 8th week of therapy. Conclusion Our findings suggest that both Bax and Fas overexpression after topical calcipotriol therapy for psoriasis might participate in the induction of apoptosis, especially of keratinocytes.