H2S in acute lung injury: a therapeutic dead end(?).

This review addresses the plausibility of hydrogen sulfide (H2S) therapy for acute lung injury (ALI) and circulatory shock, by contrasting the promising preclinical results to the present clinical reality. The review discusses how the narrow therapeutic window and width, and potentially toxic effects, the route, dosing, and timing of administration all have to be balanced out very carefully. The development of standardized methods to determine in vitro and in vivo H2S concentrations, and the pharmacokinetics and pharmacodynamics of H2S-releasing compounds is a necessity to facilitate the safety of H2S-based therapies. We suggest the potential of exploiting already clinically approved compounds, which are known or unknown H2S donors, as a surrogate strategy.