p63 immunoexpression in hair follicles of normal and alopecia X-affected skin of Pomeranian dogs

Background: Alopecia X in Pomeranians is caused by a hair cycle deregulation, associated with downregulation of key regulatory genes of the Wnt and Shh pathways, and stem-cell markers. However, the pathogenesis remains unclear. p63 is an important transcription factor correlated with the aforementioned hair cycle modulating genes. Hypothesis/Objectives: The aim of this study was to highlight possible changes of p63 immunohistochemical expression within the hair follicles in canine alopecia X compared with normal skin. Animals: Skin biopsies from 19 alopecia X-affected and six control Pomeranians were analysed. Materials and Methods: Serial histological sections of skin biopsies harbouring anagen, telogen and kenogen hair follicles were immunohistochemically evaluated for differences in p63 expression in the affected and control samples. Results: Dogs with alopecia X had a significantly decreased immunoexpression of p63 in telogen and kenogen hair follicles. Conclusions and Clinical Relevance: The decrease of p63 immunoexpression observed in canine alopecia X suggests an involvement of p63 in hair cycle.