Hydrogen Sulfide in Skin Diseases: A Novel Mediator and Therapeutic Target

Together with nitric oxide (NO) and carbon monoxide (CO), hydrogen sulfide (H 2 S) is now recognized as a vital gaseous transmitter. The ubiquitous distributions of H 2 S‐producing enzymes and potent chemical reactivities of H 2 S in biological systems make H 2 S unique in its ability to regulate cellular and organ functions in both health and disease. Acting as an antioxidant, H 2 S can combat oxidative species such as reactive oxygen species (ROS) and reactive nitrogen species (RNS) and protect the skin from oxidative stress. The aberrant metabolism of H 2 S is involved in the pathogenesis of several skin diseases, such as vascular disorders, psoriasis, ulcers, pigment disorders, and melanoma. Furthermore, H 2 S donors and some H 2 S hybrids have been evaluated in many experimental models of human disease and have shown promising therapeutic results. In this review, we discuss recent advances in understanding H 2 S and its antioxidant effects on skin pathology, the roles of altered H 2 S metabolism in skin disorders, and the potential value of H 2 S as a therapeutic intervention in skin diseases.