Human Hair Follicles Are an Extrarenal Source and a Nonhematopoietic Target of Erythropoietin

The study demonstrated that human hair follicles (HFs) are an extrarenal source and a nonhematopoietic target of erythropoietin (EPO). Researchers found that HFs express EPO and EPO receptors (EPO-R) at both mRNA and protein levels, particularly under hypoxic conditions. Although EPO did not significantly affect hair growth in vitro, it reduced chemotherapy-induced apoptosis in HFs and altered their gene expression. This suggests that EPO/EPO-R signaling in HFs may play a role in protecting against hypoxia and chemotherapy-induced stress. The findings highlighted the potential of EPO beyond its traditional role in erythropoiesis, indicating its involvement in tissue protection within the skin.