Decrease in enkephalin levels in psoriatic lesions after calcipotriol and mometasone furoate treatment.

Abstract

BACKGROUND: Enkephalins are opioid peptides that can modulate immune responses and inflammatory processes. Furthermore, they inhibit keratinocyte proliferation/differentiation in vitro. Previously, we have shown that enkephalins are present in increased amounts in lesional psoriasis. OBJECTIVE: To determine the effect of topical treatment with the vitamin D analogue calcipotriol and the corticosteroid mometasone furoate on the level of methionine-enkephalin (enk) in psoriatic lesions. METHODS: Twelve psoriatic patients were treated with calcipotriol and mometasone furoate for 14 days without or with hydrocolloid occlusion. Keratome biopsies were obtained from treated and untreated skin, and the extracted enk was quantified by radioimmunoassay. Furthermore, punch biopsies were obtained for immunohistochemical analysis. RESULTS: Clinically, both calcipotriol and mometasone furoate improved psoriasis to the same degree, the effects being more pronounced after occlusion. Histologically, treatment with mometasone furoate without occlusion decreased both the epidermal thickness/parakeratosis and the number of dermal immunocompetent cells (CD3- and CD68-positive cells). In contrast, treatment with calcipotriol without occlusion reduced the epidermal thickness and the degree of parakeratosis but decreased the number of CD3- and CD68-positive cells only slightly. The mean enk level was decreased by 26 and 86% by calcipotriol without and with occlusion and by 16 and 63% by mometasone furoate without and with occlusion, respectively. The decreases in the enk levels corresponded to the degree of clinical improvement but not to the histological changes. CONCLUSION: The increased levels of enk in psoriatic lesions are reduced in parallel with the clinical improvement induced by a topical vitamin D analogue and a corticosteroid. Because enkephalins can modulate epidermal differentiation and inflammatory processes, the findings indicate that enkephalins may play a role in the pathogenesis of psoriasis.