Phenotypic Modulation of Human Hair Matrix Cells by Environmental Influence In Vitro and In Vivo

The study by A Limat et al. investigated the phenotypic modulation of human hair matrix cells (trichocytes) under various environmental conditions both in vitro and in vivo. Trichocytes were isolated from human scalp hair follicles and cultured on feeder layers of human dermal fibroblasts (HDF). The study found that trichocytes could differentiate into stratified epithelia resembling epidermis when grown in vitro, but this differentiation was suppressed when dermal papilla cells (DPC) were used instead of HDF. Transplantation onto nude mice resulted in complete epidermal differentiation, as evidenced by tissue organization and expression of specific keratins. The presence of HDF was crucial for the development of large spheroidal structures with epidermal markers, while DPC co-culture inhibited keratinization. The research concluded that trichocytes have inherent differentiation potential influenced significantly by external factors, particularly mesenchymal cell interactions.