Hydrogen sulphide and the hyperdynamic circulation in cirrhosis: a hypothesis.

Cirrhosis is associated with the development of a hyperdynamic circulation, which is secondary to the presence of systemic vasodilatation. Several mechanisms have been postulated to be involved in the development of systemic vasodilatation, including increased synthesis of nitric oxide, hyperglucagonaemia, increased carbon monoxide synthesis, and activation of K(ATP) channels in vascular smooth muscle cells in the systemic and splanchnic arterial circulation. Hydrogen sulphide (H2S) has recently been identified as a novel gaseous transmitter that induces vasodilatation through activation of K(ATP) channels in vascular smooth muscle cells. In this brief review, we comment on what is known about H2S, vascular and neurological function, and postulate its role in the pathogenesis of the vascular abnormalities in cirrhosis.