Recent Progress in Understanding the Effect of Sympathetic Nerves on Hair Follicle Growth

The document discusses the significant role of sympathetic nerves in hair follicle growth and cycling, primarily through the release of noradrenaline. The study found that stress, which increases sympathetic activity, can disrupt the hair growth cycle and potentially lead to hair loss. Experimental data showed that the depletion of noradrenaline in mice inhibited hair growth, while its restoration promoted hair growth. The local application of a noradrenaline skin patch could prevent alopecia in rats exposed to high-dose radiation or chemotherapy. The sympathetic nerves also interact with arrector pili muscles and hair follicle stem cells, suggesting a role in hair growth. The document suggests the potential of using noradrenaline in combination with stem cell therapy for promoting hair growth, but further investigation is needed to understand the exact mechanism in humans.