Abstract 16846: Activation of Farnesoid X Receptor Signaling Mediates Atrial Myocyte Apoptosis in Patients Undergoing On-Pump Coronary Artery Bypass Grafting and Ventricular Remodeling After Experimental Myocardial Infarction

Introduction: The nuclear farnesoid X receptor (FXR) expressed in the liver functions as an endogenous sensor for bile acids. Evidence suggests FXR may act as a novel functional receptor in murine myocardium, possibly regulating apoptosis and contributing to ischaemia/reperfusion injury. Hypothesis: In diseased human heart, the expression and function of FXR is unknown. Methods: The present study examined the expression of FXR and its downstream target small heterodimer protein (SHP) and parameters of apoptosis (caspase-3 activity, pro-apoptotic BAX) in right atrial biopsies taken before aortic occlusion and after reperfusion from 59 patients undergoing on-pump coronary artery bypass graft (CABG) surgery. The patient group consisted of 15 women and 44 men with a mean±S.E. age of 66.57±1.78 and 64.02±1.25 years respectively. Results: FXR and SHP increased 2-3 fold post CABG. Atrial caspase-3 activity and BAX increased 2-3.5 fold post CABG. There was a positive correlation between atrial FXR and BAX mRNAs (...