Expression of the adipokine adiponectin is higher in the left ventricular myocardium than in epicardial adipose tissue in human end-stage heart failure and correlates with cardiac index

Purpose: Previous clinical and experimental studies have suggested adiponectin to be an adipokine with antiinflammatory, antiatherogenic, antihypertrophic, insulin-sensitizing and antiapoptotic effects. So far, expression of adiponectin was demonstrated only in adipose tissues, bone-forming cells, endothelial cells and in isolated cardiomyocytes. Therefore, the purpose of our work was to study adiponectin expression in the human left ventricle myocardium (LV) and epicardial adipose tissue (EAT) in correlation with selected clinical parameters of patients with terminal heart failure. Patients and methods: Patient study group was composed of 28 patients (average age 48±7; 22 men, 6 women) with heart failure undergoing heart transplantation. Causes of heart failure were dilated cardiomyopathy (14), restrictive cardiomyopathy (2), coronary artery disease (10) or other causes (2). Seven patients were also diagnosed with diabetes mellitus (DM). Samples of epicardial adipose tissue and LV were collected immediately after heart explantation and frozen in liquid nitrogen. Protein expression of adiponectin was determined by western blot analysis. Panel of the predefined clinical and laboratory patient characteristics were recorded to search for associations with adiponectin expression. Expression of other genes e.g. connexin 43, caveolin-1 were also determined in EAT and LV. Statistical analysis was performed using nonparametric tests with significance level at α=0.05. Results: Adiponectin expression was significantly higher in LV compared to EAT (1.8-fold, p<0,05) in entire study group. Similar results were observed in patients with and without DM (1.99-fold, p=0.053 and 1.76-fold, p<0.05 respectively). Levels of adiponectin expression in EAT significantly correlated with QRS complex duration (rs= -0.431, p<0,05). Levels of adiponectin expression in LV significantly correlated with cardiac index (rs= 0.381, p<0,05). Interestingly, we found no correlation between expression levels of adiponectin between LV and EAT. Conclusions: We have shown for the first time, that adiponectin is expressed in EAT of heart failure patients and that its expression levels are higher in the failing myocardium than in the adjacent EAT. Adiponectin levels correlated with QRS duration and with cardiac index. The work was supported by VEGA 1/0786/11.