Lack of the Vitamin D Receptor Is Associated with Reduced Epidermal Differentiation and Hair Follicle Growth

The study concluded that the absence of the Vitamin D Receptor (VDR) in mice led to reduced epidermal differentiation and impaired hair follicle growth. VDR knockout mice showed decreased expression of differentiation markers (involucrin, profilaggrin, loricrin) from birth to 3 weeks, resulting in abnormal epidermal structure and progressive alopecia by 8 months. Histological analysis revealed dilated hair follicles and dermal cysts starting at 3 weeks, worsening with age. These findings underscored the essential role of VDR in normal skin and hair follicle development, suggesting that VDR is crucial for hair growth cycles and epidermal health, possibly through mechanisms independent of its ligand.