Hydrogen sulfide-based anti-inflammatory and chemopreventive therapies: an experimental approach

Hydrogen sulfide has potent anti-inflammatory and cytoprotective properties. In the gastrointestinal tract, hydrogen sulfide contributes significantly to mucosal defence and responses to injury. This includes promotion of resolution of inflammation and healing. Inhibition of hydrogen sulfide synthesis increases the susceptibility of the gastrointestinal mucosa to injury and delays healing processes. The beneficial effects of hydrogen sulfide have been exploited in the design of novel anti-inflammatory drugs that cause negligible gastrointestinal damage. Nonsteroidal anti-inflammatory drugs are known to be effective, when used chronically, in reducing the incidence of several types of cancer. However, the toxicity of these drugs, particularly in the gastrointestinal tract, greatly limits this use. On the other hand, the gastrointestinal-safe, hydrogen sulfide-releasing anti-inflammatories show great promise for chemoprevention of cancers. This paper reviews the evidence supporting important anti-inflammatory and cytoprotective effects of hydrogen sulfide, particularly in the gastrointestinal tract. Also reviewed are the approaches taken to develop safer anti-inflammatory and cancer chemopreventive drugs by exploiting the beneficial effects of hydrogen sulfide.