Perivascular adipose tissue from the internal mammary artery in patients with severe coronary artery atherosclerosis

BACKGROUND: he internal mammary artery (IMA) is routinely used as an arterial graft for coronary artery bypass grafting with an excellent long‑term patency rate, but its protective mechanism is unclear. AIMS: We evaluated the differences between the expression of several gene in perivascular adipose tissue from the IMA (PVAT‑IMA) as compared with other fat depots in patients with severe coronary artery disease. METHODS: A total of 53 patients (13 women) with severe coronary artery disease and preserved left ventricular ejection fraction were scheduled for coronary artery bypass grafting. Clinical assessment, anthropometric parameters, and quantification of fat depots were performed in all patients. The relative expression of the following genes were obtained in PVAT‑IMA, as well as epicardial, pericardial, and subcutaneous (SF) fat samples: angiotensinogen (AGT), angiotensin I converting enzyme 1 and 2 (ACE1and ACE2), glucagon‑like peptide receptors type 1 and 2 (GLP1R and GLP2R), phospholipid transfer protein (PLTP), adiponectin (ADIPOQ), omentin‑1 (ITLN1), and uncoupling protein 1 (UCP1). RESULTS: The expression of UCP1 (median [interquartile range [IQR], 2.5 [0.91-16.6]; P <0.01) and AGT(2.22 [0.65-6.2]; P <0.01) was higher in PVAT‑IMA compared with the SF depot. ADIPOQ expression was lower in pericardial and epicardial fat depots (median [IQR], 0.44 [0.23-2.3]; P <0.01). The expression of ITLN1 was increased in PVAT‑IMA as compared with epicardial and pericardial fat (P <0.001). CONCLUSIONS: PVAT‑IMA revealed differences in the expression of selected genes in relation to SF. We found a higher expression of ITLN1 in PVAT‑IMA compared with other adipose tissue depots, which could be associated with protective mechanisms against atherosclerosis in IMA. However, this remains a subject for further studies.