Tumor necrosis factor-alpha is released from the isolated heart undergoing ischemia and reperfusion

Objectives. The purpose of this study was to examine whether tumor necrosis factor-alpha (TNF-alpha) is released directly from the ischemic myocardium undergoing reperfusion. Background. Tumor necrosis factor-alpha is a protein hormone produced by systemic leukocytes (primarily by activated macrophages). It has been implicated as a systemic mediator in the development of septic shock and other pathologic conditions. Serum TNF- alpha has also been detected in a variety of cardiac disease states and after myocardial ischemia-reperfusion injury. Methods. Nine isolated rat hearts undergoing 30 min of perfusion, followed by warm cardioplegic arrest, 1 h of global ischemia and 30 min of reperfusion, were investigated using the modified Langendorff model. Results. Significant amounts of TNF-alpha (752 ± 212 pmol/ml) were detected in the effluent during the first minute of reperfusion. Tumor necrosis factor-alpha levels correlated with postischemic deterioration in peak systolic pressures (r = 0.7882, p = 0.012), dP/dt max (r = 0.6795, p = 0.044), time-pressure integral (r = 0.7661, p = 0.0016) and postischemic creatine kinase levels (r = 0.8367, p = 0.005). The deterioration in coronary flow, however, was inversely correlated with TNF-alpha levels (r = -0.7581, p = 0.018). Conclusions. To our knowledge, this study is the first to suggest that the isolated rat myocardium synthesizes and releases TNF-alpha in response to ischemia and reperfusion, which directly correlates with the postischemic deterioration in myocardial mechanical performance and the amount of cellular necrosis.