Transgenic Erythropoietin Overexpression Inhibits Dermal Fat Formation and HIF1a in the Skin and Causes Telogen Effluvium in Mouse Pups During the First Hair Cycle

The study investigates the role of erythropoietin (EPO) in hair growth and dermal fat formation in mice. Transgenic mice overexpressing human EPO (Tg6) showed disrupted hair follicle (HF) development during the first catagen phase, leading to the formation of epithelial-lined HF cysts and truncal alopecia. This disruption was linked to increased EPO and HIF1a expression, which affected lipogenesis and lipolysis in dermal fat. In contrast, EPOR knockout in HF stem cells did not impact hair growth or body weight. The findings suggest that EPO-HIF1a interaction is crucial for normal HF development and homeostasis.