Abstract
Introduction: The view of hydrogen sulfide has changed from a toxic by-product to a crucial signaling molecule, with enormous potential as a pharmacological target for diseases ranging from heart disease to sepsis. Despite this progression of ideas, there is still a large amount that is unknown about this gaseous signaling molecule. Hydrogen sulfide has been implicated as a tissue protectant in many pathological conditions, the mechanisms of tissue protection is a point of controversy, particularly distinguishing the direct actions from the indirect downstream effects of hydrogen sulfide. This point of controversy is particularly pertinent in inflammation research.
Areas covered: Current research into the pathways in which hydrogen sulfide can act as a pro-inflammatory molecule and as an anti-inflammatory molecule.
Expert opinion: How controversies regarding hydrogen sulfide may have occurred is discussed. Addressed are the direct and indirect pathways of hydrogen sulfide on inflammation, the effects of different concentrations of hydrogen sulfide and how the effects of hydrogen sulfide on the immune system vary with different delivery mechanisms. Furthermore, there is a discussion on what key gaps exist in current knowledge and must be addressed before hydrogen sulfide can be considered a valid pharmacological target.