Perivascular fat of the internal mammary artery in patients with severe coronary artery atherosclerosis.

BACKGROUND The internal mammary artery (IMA) is routinely used as an arterial graft for coronary artery bypass grafting (CABG) with an excellent long-term patency rate, but its protective mechanism is unclear. AIMS Our study evaluates the differences of several genes' expression in perivascular fat from internal mammary artery (PVAT-IMA) vs. other fat depots in patients with severe coronary artery disease (CAD). METHODS Fifty-three patients (13 females) with severe CAD and preserved left ventricle ejection fraction were scheduled for CABG. 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, epicardial (EF), pericardial (PF) and subcutaneous (SF) fat samples: Angiotensinogen (AGT), Glucagon-Like-Peptide Receptors (GLP-1R and GLP-2R), Phospholipid Transfer Protein (PLTP), Adiponectin, Omentin-1 and Uncoupling Protein-1 (UCP-1). RESULTS The UCP-1 [2.5 (0.91 - 16.6); P < 0.01] and AGT [2.22 (0.65 - 6.2); P < 0.01] expression were significantly higher in PVAT-IMA and adiponectin [0.32 (0.08 - 1.63); P < 0.01] and GLP - 2R [0.37 (0.05 - 1.55); P < 0.01] were lower compared to SF depot. The expression of genes in PVAT-IMA vs. EF was significantly increased omentin-1 in PVAT-IMA (P < 0.001). CONCLUSIONS The PVAT-IMA reveals differences in expression of selected genes in relation to SF. We found a significantly higher expression of omentin-1 in PVAT-IMA compared to other adipose tissue depots, which could be associated with protective mechanisms against atherosclerosis in IMA. However, it should be a subject for further studies.