Adipocytokine resistin correlates with oxidative stress and myocardial injury in patients undergoing cardiac surgery

Abstract

Adipocytokines are hormones regulating energy metabolism and appetite and according to recent reports also inflammatory responses including ischaemia-reperfusion injury. Based on experimental data, we hypothesized that the levels of adipocytokines adiponectin, adipsin, leptin and/or resistin would correlate with myocardial injury, inflammation and oxidative stress during cardiac surgery. Thirty-two patients undergoing an elective on-pump coronary artery bypass graft surgery (CABG) with cardiopulmonary bypass (CPB) were recruited into the study. Blood samples were collected after the induction of anaesthesia, and at the onset of CPB, 1 and 15 min after the removal of aortic cross-clamp and 4 and 24 h after the onset of CPB. Samples were analysed for levels of four adipocytokines (adiponectin, adipsin, leptin and resistin) and markers of oxidative stress [myeloperoxidase (MPO) and 8-isoprostane], inflammation [interleukin-6 (IL-6)] and myocardial injury [troponin T (TnT)]. Adiponectin and adipsin concentrations declined, while leptin and resistin levels increased significantly by 24 h after the onset of the operation. Interestingly, basal levels of resistin (r = 0.41, P = 0.020) as well as the maximal increase occurring in resistin levels during the 24-h follow-up (r = 0.49, P = 0.005) correlated positively with TnT release. In addition, the reperfusion-induced elevation in resistin levels correlated positively with oxidative stress measured as increases in MPO concentrations. As an original finding, we report here that resistin levels correlate with oxidative stress and myocardial injury in patients undergoing cardiac surgery. In addition, leptin levels were increased on the first postoperative day, but only minor declines were found in adiponectin and adipsin levels. Resistin has been implicated in unfavourable metabolic, cardiovascular and inflammatory responses: it may thus serve as a useful biomarker or a drug target in conditions complicated by ischaemia-reperfusion injury.