Hydrogen sulfide contributes to cardioprotection during ischemia-reperfusion injury by opening K ATP channels

Characterization of a novel, water-soluble hydrogen sulfide-releasing molecule (GYY4137): new insights into the biology of hydrogen sulfide

BACKGROUND

The potential biological significance of hydrogen sulfide (H(2)S) has attracted growing interest in recent years. The aim of this study was to characterize a novel, water-soluble, slow-releasing H(2)S compound [morpholin-4-ium 4 methoxyphenyl(morpholino) phosphinodithioate (GYY4137)] and evaluate its use as a tool to investigate the cardiovascular biology of this gas.

METHODS AND RESULTS

The acute vasorelaxant effect of drugs was assessed in rat aortic rings and perfused rat kidney in vitro and in the anesthetized rat in vivo. The chronic effect of GYY4137 on blood pressure in normotensive and spontaneously hypertensive rats was determined by tail-cuff plethysmography. GYY4137 released H(2)S slowly both in aqueous solution in vitro and after intravenous or intraperitoneal administration in anesthetized rats in vivo. GYY4137 caused a slow relaxation of rat aortic rings and dilated the perfused rat renal vasculature by opening vascular smooth muscle K(ATP) channels. GYY4137 did not affect rat heart rate or force of contraction in vitro. GYY4137 exhibited antihypertensive activity as evidenced by ability to reduce N(G)-nitro-L-arginine methyl ester-evoked hypertension in the anesthetized rat and after chronic (14-day) administration in spontaneously hypertensive rats.

CONCLUSIONS

These results identify GYY4137 as a slow-releasing H(2)S compound with vasodilator and antihypertensive activity. GYY4137 is likely to prove useful in the study of the many and varied biological effects of H(2)S. GYY4137 may also prove of therapeutic value in cardiovascular disease.

Exogenous hydrogen sulfide postconditioning protects isolated rat hearts against ischemia-reperfusion injury

Hydrogen sul fi de (H2S) is an endogenous gaseous mediator, produced by cystanthionine-gamma-lysase (CSE) in the cardiovascular system. Hydrogen sulfide given before ischemia can decrease myocardial ischemia and reperfusion injury. The present study investigated: (1) if hydrogen sulfide given at early reperfusion could decrease myocardial ischemia and reperfusion injury; (2) if the protective effects of hydrogen sulfide were related to mitochondrial ATP-sensitive K+ (KATP) channels opening. In isolated rat heart model, treatment of heart with NaHS (H2S donor) at the onset of reperfusion resulted in a concentration-dependent limitation of infarct size and creatine kinase release. The optimal NaHS concentration for cardioprotection is 1 microM. The cardioprotective effects of NaHS (1, 10 microM) were comparable to those of ischemic postconditioning. The KATP channels blocker, Glibenclamide or 5-hydroxydecanoate, reversed the cardioprotective effects of NaHS. The datum provided further evidence that exogenous H2S postconditioning protected rat heart against ischemia and reperfusion injury. Mitochondrial KATP channel opening is implicated in the postconditioning of H2S.