Role of Central and Peripheral CRH in Skin

Background: Hypothalamic corticotrophin-releasing hormone (CRH) has a key role in coordinating and controlling complex responses to stress, both systemically, by stimulating the expression of the pituitary POMC gene, and thus, resulting in increased production of ACTH and adrenal glucocorticoid release, and locally since CRH has been identified in several peripheral tissues. CRH seems to exert its effects through interaction with two known so far receptors, CRF1R and CRF2R. The mRNA and protein of CRH family of peptides and their receptors are expressed at several peripheral tissues including rodent and human skin. In addition to CRH, skin expresses POMC and its products, including ACTH while recent studies have shown the presence of glucocorticoids also in skin. Objective: This review aims to summarize the role of CRH in the physiology and pathophysiology of human and rodent skin. Results: It is clear that a) locally produced CRH is involved in the inflammatory process, b) CRH has been shown to stimulate angiogenesis in vivo and chemotaxis of endothelial cells in vitro, and c) CRH mRNA and peptide have been identified in skin. Conclusion: Based on the above we hypothesize that CRH plays a crucial role in several inflammatory pathologies of the skin as well as in cutaneous wound healing, which are all discussed in the present review. Keywords: CRH, CRFR, skin, psoriasis, wound healing, dermatitis, acne, alopecia areata.