Thermogenin expression in cardiac adipose tissue of patients with coronary artery atherosclerosis

Aim. To evaluate thermogenin expression in epicardial (EAT) and perivascular (PVAT) adipose tissue (AT) of patients with coronary artery atherosclerosis. Material and methods. The study included patients with stable coronary artery disease (CAD) and acquired non-rheumatic heart disease (AHD). During cardiac surgery, biopsies of 3-5 g of subcutaneous adipose tissue (SAT), EAT, and PVAT were obtained from each patient. Thermogenin (UCP1) expression in AT was assessed using immunofluorescence staining. Statistical analysis was performed using GraphPad Prism 8 (GraphPad Software). Results. Thermogenin expression was observed in all AT loci, regardless of the underlying disease. UCP1 expression was highest in SAT of patients with CAD. In adipocytes, EAT is lower relative to SAT and PVAT, while among individuals with AHD, UCP1 levels were highest in EAT and PVAT compared to SAT. Analysis of UCP1 protein expression depending on the disease revealed that thermogenin levels in EAT adipocytes in patients with CAD were lower than in the AHD group, while in PVAT, it was higher than in AHD. Conclusion. Coronary atherosclerosis is associated with high thermogenin protein expression in AT surrounding the coronary arteries, but not in the EAT. This suggests that adaptive thermogenesis in EAT in CAD is reduced due to a decrease in the number of UCP1-positive adipocytes, activation of inflammation, and oxidative stress.