Sleeve Gastrectomy in Obese Zucker Rats Restores Cardiac Function and Geometry Toward a Lean Phenotype Independent of Weight Loss.

OBJECTIVE: Bariatric surgery, including sleeve gastrectomy (SG), significantly improves cardiac geometry and function in patients with heart failure. In this study, we used the obese Zucker rat as an animal model of heart failure with preserved ejection fraction (HFpEF) to test the hypothesis that a SG will improve cardiac function independent of weight loss. METHODS AND RESULTS: Obese, male Zucker rats underwent SG, pair-fed sham, or ad-lib sham surgery. Lean Zucker rats also underwent ad-lib sham surgery. Echocardiograms were performed preoperatively and at 6 weeks postoperatively. Obese SG and obese pair-fed sham rats had similar body weights postoperatively. Obese SG and lean, ad-lib, sham rats had a significant increase in postoperative stroke volume, and left ventricular internal diameter in diastole and systole. SG preserved systolic function and significantly improved isovolumetric relaxation time (13.9 ± 2.4 to 11.1 ± 2.1 ms, P = .02) independent of weight loss. DISCUSSION: SG has a beneficial impact on both systolic and diastolic cardiac function in obese Zucker rats toward a lean phenotype independent of weight loss and caloric restriction. These findings may represent a weight-loss independent mechanism generated from the gastrointestinal tract that has the potential to improve diastolic dysfunction independent of obesity status and translate to patients with HFpEF.