Hydrogen sulfide-based therapeutics: exploiting a unique but ubiquitous gasotransmitter

Hydrogen sulfide (H2S) is an important signalling molecule; it influences physiological and pathophysiological processes throughout the body.Accurate measurement of hydrogen sulfide remains a challenge, largely because it is highly reactive. H2S synthesis from the microbiome contributes substantially to 'tissue levels' of H2S.In circumstances of anoxia or hypoxia, H2S can 'rescue' mitochondria. H2S also exerts important anti-inflammatory and cytoprotective effects while driving the resolution of tissue injury.Animal studies of several H2S-releasing drugs show considerable promise for the safe treatment of a wide range of disorders, and several such drugs are now in clinical trials.Coupling of an H2S-releasing moiety to other drugs, such as anti-inflammatory drugs, can improve efficacy and/or substantially reduce toxicity.Based on studies in animal models, H2S-based drugs may be effective in chemoprevention of cancer, and have also shown promise in the treatment of several neurological disorders, such as Alzheimer disease.