Introduction Several reports suggest that bariatric surgery significantly improves cardiac function in patients with obesity cardiomyopathy. The mechanism is unknown but may be due to weight-loss independent factors. We predict that the changes in gastrointestinal anatomy after a rodent model of sleeve gastrectomy (SG) will have weight-loss independent effects on cardiac dysfunction. Methodology Cardiac dysfunction was induced by feeding a 60% kcal from fat diet to male Wistar rats for 10 weeks. Rats underwent either a SG (n = 12) or pair-fed, PF (n = 8) sham surgery. Echocardiograms were performed pre- and post-operatively at 6 and 13 weeks. Blood samples were obtained at 10 weeks post-operatively for assessment of insulin sensitivity and heart failure. Results Forty-four percent of SG rats had a normal ejection fraction (EF) at 13 weeks (“responders”) compared to five SG rats who did not recover EF (“non-responders”). Zero percent of the PF rats normalized EF (p = 0.03). SG responders had a smaller left ventricular internal diameter in systole and end systolic volume with improved systolic function compared to SG non-responders (EF 90.7 ± 1.7 vs. 75.4 ± 3.6%, p = <0.001). At 10 weeks post-operatively, plasma glucose and B-type natriuretic peptide levels were significantly lower in SG rats compared to PF rats. Conclusions A SG significantly improved systolic function in 44% of rats with diet-induced obesity and cardiac dysfunction. This improvement is related to weight-loss independent effects of the surgery on the entero-cardiac axis. These results offer a novel weight-loss independent, metabolic role for bariatric surgery as a potential treatment modality for obesity-associated cardiac dysfunction.
Introduction.-Bariatric surgery, including sleeve gastrectomy (SG), significantly improves cardiac geometry and function in patients with heart failure. In this study, we utilized 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 pre-and at 6 weeks post-operatively. Obese SG and obese pair-fed sham rats had similar body weights post-operatively. Obese sleeve gastrectomy and lean, ad-lib, sham rats had a significant increase in post-operative stroke volume, left ventricular internal diameter in diastole and systole. SG preserved systolic function and significantly improved isovolumetric relaxation time (13.9 ± 2.4 ms to 11.1 ± 2.1 ms, p=0.02) independent of weight loss.Discussion.-SG has a beneficial impact on both systolic and diastolic cardiac function in obese, Zucker rats towards 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.
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