Repair or Regenerate, You Must Choose

The document discussed the long-held belief that hair follicles could not regenerate once lost, as they were formed during embryonic development and were not replaced after death. However, a study by G. Cotsarelis challenged this dogma by demonstrating that scarred skin in wounded mice could produce new hair follicles, indicating a regenerative capacity previously thought absent in mammals. This discovery was significant as it showed that new hair follicles could form from epidermal stem cells in the basal layer of the epidermis, rather than from the expected bulge stem cells. This finding suggested that mammals might have a limited but existing potential for organ regeneration, contrasting with the regenerative abilities of certain amphibians.