Lymphocyte subsets in epicardial, thymic and subcutaneous adipose tissue during advanced coronary atherosclerosis in patients with coronary artery disease

The important role of epicardial (EAT) and thymic (TAT) adipose tissue in the development of atherosclerosis in patients with coronary artery disease (CAD) is widely discussed. The purpose of the study was to investigate the lymphocyte subsets and FoxP3+Treg lymphocytes in epicardial, thymic and subcutaneous adipose tissue depending on the severity of coronary atherosclerosis in patients with chronic CAD. We examined 24 patients with CAD (21 men; mean age 65.0 (58.0-68.0) years) scheduled for open-heart surgery. In samples of EAT, TAT and subcutaneous adipose tissue (SAT), the content of CD4+, CD8+, B lymphocytes, NK and NKT cells, CD4+CD25hiFoxP3+ and CD4+CD25lowFoxP3+T regulatory lymphocytes (Treg) and a proportion of Tregs with FoxP3 nuclear translocation was determined by imaging flow cytometry. Depending on the severity of atherosclerosis, assessed according to Gensini Score, patients were divided into groups: group 1 – patients with Gensini Score 65; group 2 – patients with Gensini Score ≥ 65. Patients in group 2 had higher frequency of EAT CD4+CD25lowTreg with FoxP3nuclear translocation, TAT CD8+T lymphocytes and NK cells, a lower content of TAT double positive CD4+CD8+T lymphocytes, and a tendency towards a decrease of frequency of TAT CD4+CD25hiTreg with FoxP3 nuclear translocation compared to patients in group 1. The level of nuclear translocation of FoxP3 in CD4+CD25hiTreg cells in TAT was inversely related to the proportion of CD8+T lymphocytes (rs = -0.653; p = 0.012) and NK cells (rs = -0.723; p = 0.003) in TAT, and directly – to the proportion of double positive CD4+CD8+T lymphocytes in TAT (rs = 0.567; p = 0.034) and the value of the waist-to-hip ratio (rs = -0.474; p = 0.041). Further research is required to study the molecular mechanisms of these relationships in patients with coronary atherosclerosis and chronic coronary artery disease.