Subcutaneous adipose tissue omentin-1 in coronary artery disease patients

Imbalance in secretion of adipose tissue adipokines may play a role in the development of cardiovascular pathology associated with obesity. Omentin-1 is an adipokine with antiinflammatory, antioxidant and antiatherogenic properties, therefore it’s serum concentration is considered as a biomarker of cardiovascular diseases. Objective: Investigation of omentin-1 gene (ITLN1) expression in SAT in coronary artery disease (CAD) patients and in the control group, including сomparative analysis of ITLN1 mRNA and protein levels in SAT, omentin-1 serum concentration, as well as an assessment of the correlation of the ITLN1 gene expression with the mRNA level of PPARG gene encoding peroxisome proliferator-activated receptor gamma as the key regulator of adipogenesis. Subcutaneous adipose tissue (SAT) biopsies and serum samples from 74 patients with CAD, undergoing coronary artery bypass grafting, and 16 persons of the control group, were included in the study. ITLN1 and PPARG mRNA levels were detected by quantitative real-time PCR. Omentin-1 protein level in SAT was measured by western-blot. Serum omentin-1 concentration was determined by ELISA. Serum omentin-1 concentration was decreased in the CAD group compared to controls (p<0,01), and inversely correlated with waist circumference among all examined individuals (r = -0.307, p <0.01). No differences were found in the ITLN1 mRNA and omentin-1 protein levels in SAT between the studied groups. The ITLN1 mRNA and omentin-1 protein levels in SAT were positively correlated (r=0,373, p<0.05). A higher level of omentin-1 protein in SAT was detected in men compared with women (p <0.05), however, omentin-1 serum concentration was higher in women (p <0.05). The PPARG mRNA level in SAT was lower in patients with CAD (p <0.05). Omentin-1 serum concentration was positively correlated with the PPARG mRNA level in SAT (r =0.338, p <0.05). The ITLN1 mRNA and omentin-1 protein levels were negatively correlated with the PPARG mRNA in SAT among all examined individuals (r = -0.444, p <0.01 and r = -0.475, p <0.01, respectively). These correlations persisted only in men subgroup when men and women were analyzed separately (r= -0,422, p<0,05 and r= -0,609, p<0,01, respectively). CAD, adiposity and male gender are associated with reduced omentin-1 serum concentration. Gender differences of omentin-1 gene expression regulation in SAT were demonstrated.