Epicardial adipose tissue and intracoronary adrenomedullin levels in coronary artery disease.

ABSTRACT

The aim of the study was to test 1) whether chronic and stable coronary artery disease (CAD) could downregulate epicardial fat adrenomedullin synthesis and secretion, and decrease intracoronary plasma adrenomedullin levels, and 2) whether intracoronary plasma adrenomedullin levels could be related to epicardial adipose tissue adrenomedullin gene and protein expression in subjects with CAD. We examined 12 patients with CAD who required coronary artery bypass graft (CABG) and 10 patients with non-CAD who underwent cardiac surgery for valve replacement. Plasma levels of adrenomedullin were measured in peripheral vein circulation, in left coronary artery (LCA) and coronary sinus (CS) during coronary angiography. Epicardial adipose tissue biopsy for Reverse Transcription and Real-Time PCR (RT-PCR) adrenomedullin mRNA analysis and Western Blotting (WB) protein expression was performed during cardiac surgery in all subjects. Peripheral, LCA, and CS plasma adrenomedullin levels were significantly lower in CAD patients than in those with non-CAD (3.0+/-0.9 vs. 4.4+/-0.9 pg/ml p<0.01; 2.9+/-1 vs. 4.05+/-0.8 pg/ml, p<0.01, 3.1+/-0.9 vs. 3.98+/-0.9 pg/ml p=0.04, respectively). However, CS adrenomedullin levels were not statistically different than those in LCA suggesting that adrenomedullin was not secreted from epicardial fat into the coronary artery lumen. Epicardial fat adrenomedullin mRNA levels and protein expression were lower in patients with CAD than in those with non-CAD (p<0.01 for both). We conclude that 1) epicardial fat adrenomedullin gene and protein expression can be downregulated in CAD subjects, and 2) intracoronary adrenomedullin levels are lower in CAD. No evidence that epicardial adipose tissue really contributes intracoronary adrenomedullin can be provided at this time.