Correlazione tra infiltrazione macrofagica del tessuto adiposo epicardico, infiammazione, adipochine e danno vascolare coronarico su base aterosclerotica

Interest has recently focused on epicardial and perivascular adipose tissue, due to their possible relation with atherosclerosis. Biopsies were collected from subcutaneous (SAT), epicardial (EAT) and periaortic (AOAT) and atrial muscle, in 34 males aged between 51 and 80 years, undergoing elective cardiac surgery eithen for coronary bypass grafting (16 pts) or valve replacement (18 pts). Weight, height, Body Mass Index (BMI), waist, as well as glucose, insulin and HOMA index, total cholesterol, HDL, LDL, triglycerides were determined in all the subjects. Adiponectine, MCP-1 and CD-68 mRNA levels were determined by real time polymerase chain reaction (qRT- PCR) on fat biopsies. Adipocyte size was determined by electron microscopy and morphometry. Immunohistochimical study with PLP was done on atrial muscle biopsies. MCP-1 and CD-68 gene expression was significantly higher in both AOAT and EAT than in SAT. Adiponectine gene expression resulted to be significantly higher in SAT than in EAT, and in EAT than in AOAT. Adiponectine size in AOAT was significantly smaller than in EAT, and in EAT than in SAT. Adiponectine, MCP-1 and CD-68 gene expression was not statistically different between CAD and nonCAD. The insulin resistant subjects showed higher gene expression of MCP-1 and CD-68 and lower of Adiponectine in SAT and in AOAT than insulin sensitive subjects. Adipocyte size in EAT was significantly bigger in IR; SAT adipocyte size was not statistically different between IR and IS subjects. Ectopis adipocytes in atrial muscle were identified by immunohistochimical analysis with PLP. Intramyocardial size of adipocytes was smaller than AOAT and SAT adipocyte size. Our data seem to suggest a significant relation between insulin resistance and inflammation in fat and between insulin resistance and adipocyte size both in SAT and AOAT, as well as that perivascular fat shows a more proinflammatory profile and smaller adipcytes than EAT and SAT. All together these findings seem to add relevance to the inflammation in perivascular fat as a possible contributor of cardiovascular diseases. The presence of intramyocardial adipocytes could lead pathological changes of heart muscle.