Lower Proximal Cup Cells But Not Bulge Stem Cells Regenerate Hair Follicles After Chemotherapy Injury

The study investigated the regeneration of hair follicles after chemotherapy-induced injury in mice, focusing on the role of different stem cell populations. It was found that basal lower proximal cup cells, rather than bulge stem cells, were responsible for regenerating hair follicles following damage from the chemotherapeutic agent cyclophosphamide. These lower proximal cup cells, which did not show typical stem cell markers and were immotile under normal conditions, became motile and actively migrated to repair the damaged hair bulbs. The study concluded that these cells are highly plastic progenitor cells capable of timely regeneration after chemotherapy, while bulge stem cells remained inactive during this process.