Association of lipoprotein-associated phospholipase A2 levels with epicardial adipose tissue adipocyte size and metabolic parameters in patients with coronary artery disease

Introduction. Lipoprotein-associated phospholipase A2 (Lp-PLA2) is considered to be an independent marker of vascular inflammation and atherosclerosis progression. Epicardial adipose tissue (EAT) actively participates in the pathogenesis of coronary artery disease (CAD) through modulation of metabolism. The potential links between Lp-PLA2 levels, metabolic parameters, and EAT morphology in patients with CAD remain unexplored.

Aim: To investigate the relationships between blood Lp-PLA2 content, lipid and glucose metabolism, and morphometric parameters of the epicardial fat depot assessed at the cellular and tissue levels in patients with established chronic CAD.

Material and Methods. The study included 217 patients with CAD. Blood concentrations of Lp-PLA2, sortilin, glucagon, C-peptide, glucose, HbA1c, and lipid profile were determined. EAT thickness was measured. In 42 patients, EAT adipocyte size and the degree of their hypertrophy were assessed. Patients were divided into two groups according to Lp-PLA2 level: group 1 (n = 205), with concentrations not exceeding the 95th percentile; group 2 (n = 12), with concentrations above the 95th percentile.

Results. Patients in group 2 had higher levels of sortilin and glucagon, increased EAT thickness, and a predominance of hypertrophied adipocytes. In group 1, Lp-PLA2 concentration correlated significantly with total cholesterol, C-LDL, glucose, HbA1c, mean EAT adipocyte size, and the proportion of hypertrophied cells. In men in group 1 with type 2 diabetes, Lp-PLA2 concentration was associated with BMI and EAT morphometry, whereas in women in group 1 with type 2 diabetes it was associated with lipid and glucose metabolism parameters. Group 1 patients with a mean EAT adipocyte size greater than 89 μm had higher blood levels of Lp-PLA2 and C-peptide compared with those with a mean EAT adipocyte size below 89 μm.

Conclusion. Lp-PLA2 level is closely related to the morphometric characteristics of the epicardial fat depot at both the cellular and tissue levels, as well as to lipid and glucose metabolism indices in patients with chronic CAD. Extremely high Lp-PLA2 concentrations are associated with increased EAT thickness, hypertrophy of EAT adipocytes, and elevated sortilin and glucagon levels. Among patients with moderate Lp-PLA2 values, the presence of large EAT adipocytes was accompanied by higher C-peptide levels, and sex differences were observed: in women, Lp-PLA2 concentration was linked to lipid and glucose metabolism parameters, whereas in men it was linked to EAT morphometry. These findings underscore the importance of comprehensive assessment of systemic and local metabolic markers, including Lp-PLA2, for cardiovascular risk stratification in CAD.

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