Changes of different subtypes of adiponectin in epicardial fat in patients with coronary heart disease

Abstract

Objective To study the difference of the secretion and synthesis of adiponectin in different parts of adipose tissue in patients with coronary heart disease (CHD). Methods The serum, epicardial adipose tissue (EAT) and subcutaneous adipose tissue (SAT) in over 50-years old male patients with CHD or valvular heart disease as control group. The patients with CHD were excluded by coronary angiography in control group. Serum adiponectin concentrations were examined in CHD group and control group by enzyme linked immunosorbent assay (ELISA). Serum adiponectin types were classified in accordance with the molecular weight of high-molecular-weight (HMW), medium molecular weight (MMW) and low molecular weight (LMW) in CHD group and non-CHD group by gel filtration chromatography. Real-time PCR was used to detect the expression of adiponectin mRNA in epicardial adipose cells and subcutaneous adipose cells. The levels of HMW MMW LMW adiponectin in adipose cells were determined by non-hearting and non-reducing sodium dodecyl sulfate polyacrylamide gel electropheresis (SDS-PAGE). Results As compared with non-CHD group, the concentration of serum HMW in CHD group was significantly reduced [(0.55±0.18) mg/L vs. (0.31±0.12) mg/L, t=3.472, P 0.05; LMW: (0.48±0.22) mg/L vs. (0.53±0.20) mg/L, t=1.712, P>0.05]. The expression of adiponectin mRNA in CAD epicardial group was significnatly downregulated when compared with autologous subcutaneous group (0.810±0.101 vs. 1.102±0.135, t=3.351, P<0.01) and control epicardial group (0.810±0.101 vs. 1.008±0.146, t=3.363, P<0.01). The proteomics revealed that the HMW content in CHD group decreased significantly as compared with non-CHD epicardial group and subcutaneous tissue group, and the rest two types of adiponectin showed no statistically significant differences. Conclusion The low expression of adiponectin in patients with CHD is located in the EAT and mainly decreased as the form of HMW adiponectin. Key words: Adiponectin; Epicardial adipose tissue; Coronary artery disease