Carbon monoxide improves cardiac energetics and safeguards the heart during reperfusion after cardiopulmonary bypass in pigs

SPECIFIC AIMSIschemia-reperfusion injury (IRI) associated with cardioplegia, mimicking cardiopulmonary bypass and hypothermic cardiac arrest as may occur during cardiac surgery for aortic coronary grafting or valve replacement, leads to decreased efficiency of ATP generation, to cardiac edema and cardiomyocyte apoptosis, and to difficulty in restarting the heart beat. We tested whether pretreatment for 2 h with 250 ppm carbon monoxide (CO) would improve these parameters in an IRI model in which the pigs were put on cardiopulmonary bypass for 2 h followed by 1 h of reperfusion.PRINCIPAL FINDINGS1. Improvement in energetics with CO pretreatmentATP concentrations were significantly elevated in CO-treated compared with control hearts at the end of reperfusion (P<0.05), which correlated with decreased ADP and AMP levels measured in the same samples. The ATP/ADP ratio, a parameter relating to energy status of the heart, was also elevated (P<0.05). The phosphocreatine (PCr) and GTP changes generally followed tha...