Immunohistochemical expression of vitamin D receptor and Wnt signaling pathway molecules in psoriasis.

Introduction: Psoriasis is a prevalent, complex, immune-mediated illness. There is some evidence in the literature supporting the involvement of the Wnt signaling pathway in psoriasis. No previous studies have focused on the association between the Wnt signaling pathway and vitamin D receptor (VDR) expression in psoriasis. This study investigates the expression of VDR and mediators of the canonical (β-catenin) and non-canonical (Wnt5a) Wnt signaling pathway in psoriatic lesional skin biopsy specimens compared to controls.

Methods: A cross-sectional study conducted on skin punch biopsy specimens from 42 psoriasis patients were stained with VDR, β-catenin, and Wnt5a and compared with 42 control biopsies. Patients' demographics, clinical data, and serum vitamin D levels were recorded.

Results: VDR showed nuclear localization with significant downregulation in the psoriasis specimens compared to controls. β-catenin (membranous) and Wnt5a (cytoplasmic) showed significant upregulation in the psoriasis specimens. When the expressions of VDR, β-catenin, and Wnt5a were compared based on disease severity, no differences were found between mild, moderate, and severe subgroups of the disease. Late-onset psoriasis patients had lower VDR and Wnt5a histoscores compared to the early-onset group. A trend toward a positive correlation was observed between the histoscores of VDR and Wnt5a.

Conclusion: Our findings confirm the significance of VDR signaling in the pathophysiology of psoriasis and strengthen the relationship between this disease and the Wnt signaling pathway. There was evidence that there is an association between VDR status and Wnt5a expression.