Aging, alopecia, and stem cells

The document examines the impact of both genetic and environmental factors on hair follicle stem cell (HFSC) aging and hair growth. It highlights the importance of the transcription factor Foxc1 in maintaining HFSC quiescence and niche structure, with its reduced expression leading to a shorter resting phase and hair loss. Additionally, the study by Matsumura et al. demonstrated that repeated hair cycling can cause DNA damage in HFSCs, resulting in the breakdown of type XVII collagen and the loss of the stem cells' ability to self-renew, which ultimately leads to hair loss. These findings suggest that hair cycling and aging are influenced by intrinsic stem cell characteristics and external factors such as the dermal environment and hormones, offering potential avenues for alopecia treatments through the modulation of the HFSC microenvironment or rejuvenation of HFSCs.