Hair-Growth-Promoting Effect of Conditioned Medium of High Integrin α6 and Low CD 71 (α6bri/CD71dim) Positive Keratinocyte Cells

The 2015 study demonstrated that conditioned medium (CM) from keratinocyte stem/progenitor cells (KSCs) with high integrin α6 and low CD71 expression could promote hair growth by increasing the proliferation of human hair follicle dermal papilla cells (HFDPCs) and outer root sheath (ORS) cells. The CM also induced phosphorylation of AKT and ERK1/2, which are important signaling pathways for cell growth. In vivo experiments showed that subcutaneous injection of KSC-CM into mice led to enhanced hair growth and increased proliferation of hair matrix keratinocytes. The study identified six growth factors within the KSC-CM that, when combined into a cocktail, significantly increased the proliferation of HFDPCs and ORS cells and improved hair growth in mouse models. These growth factors were amphiregulin, insulin-like growth factor binding protein-2, insulin-like growth factor binding protein-5, granulocyte macrophage-colony stimulating factor, platelet-derived growth factor-AA, and vascular endothelial growth factor. The findings suggest that KSC-CM or a combination of these recombinant growth factors could be potential treatments for promoting hair growth.