H2S: A “Double face” molecule in health and disease

Abstract H 2 S is a colorless, poisonous, and flammable gas with the characteristic foul odor of rotten eggs. H 2 S is present in effluent from hydrothermal vents and sulfur springs, which have been proposed to act as “pores” in the Earth surface, providing a source of energy in the form of reducing equivalents and of iron‐sulfur centers. Remarkably, H 2 S‐producing machineries or H 2 S‐utilization capacity remain within a great diversity of microorganisms. In particular, two classes of bacteria have been identified, that is, sulfate‐ and sulfur‐reducing and sulfur‐oxidizing bacteria, both contributing to the balance of the H 2 S level. The human body produces H 2 S and uses it as a signaling molecule in several physiological processes. However, many diseases, including neurological diseases, cardiovascular diseases, inflammation, and metabolic disorders, have been linked to abnormal endogenous H 2 S functions and metabolism. Remarkably, in recent years, the therapeutic administration of H 2 S(‐donors) appears relevant in the treatment of some diseases. Here, H 2 S metabolism, as well as its physiological and pathological roles in humans is reviewed. Furthermore, the therapeutic use of H 2 S is discussed. © 2012 BioFactors, 2013