The Mesenchymal Component of Hair Follicle Neogenesis: Background, Methods, and Molecular Characterization

The 2010 document provides an in-depth analysis of the role of mesenchymal cells, particularly follicular dermal papilla (FDP) and dermal sheath (DS) cells, in hair follicle development and regeneration. It outlines the historical evidence for the hair-inducing properties of these cells, the methods for their isolation and culture, and the molecular markers indicative of their trichogenicity. The paper underscores the necessity of FDP and DS cells in hair follicle morphogenesis, their unique in vitro properties, and the expression of specific biomarkers like alkaline phosphatase. It also addresses the challenges in preserving the hair inductive capacity of FDP cells in culture, suggesting that co-culture with epithelial cells and keratinocyte conditioned medium may be beneficial. The document further discusses the importance of WNT and BMP signaling in maintaining trichogenicity, the aggregative behavior of FDP cells, and the significance of the extracellular matrix in hair follicle formation. Various assays for assessing trichogenicity are detailed, and the paper calls for more research to fully understand the molecular factors involved in hair induction. It also notes the heterogeneity of FDP cells and the potential of DS cells as progenitors for FDP cells, as well as other possible trichogenic cell populations. The document concludes with the need for robust assays for human hair follicle regeneration and the inclusion of functional activity measures in research. It is a review of multiple studies and does not report on a specific number of subjects.