Early Weight Loss Independent Effects of Sleeve Gastrectomy on Diet-Induced Cardiac Dysfunction in Obese, Wistar Rats

Abstract

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.

Bariatric surgery as a treatment for heart failure: review of the literature and potential mechanisms

“…It is possible that gastrointestinal manipulation by surgery beneficially alters the entero-cardiac axis through one of these mechanisms providing additional improvement in cardiac function beyond the impact of weight loss. We recently published that in a rodent of model of sleeve gastrectomy and diet-induced cardiac dysfunction, sleeve gastrectomy significantly improved systolic function in 44% of rats in a weight-loss independent manner (59) . Rats with improved systolic function also had significantly smaller left ventricular internal diameter in systole and end systolic volume without differences in diastolic function.…”

Facilitated Ca2+ homeostasis and attenuated myocardial autophagy contribute to alleviation of diabetic cardiomyopathy after bariatric surgery

“…As a novel therapy, bariatric surgery has been demonstrated to provide rapid and sustained remission in type 2 diabetes mellitus (T2DM) and associated complications (32,34). It has attracted increasing attention because of its effectiveness in alleviating diabetic cardiac dysfunction (17,46), which was reported to be independent of weight loss or dietary changes (13). However, the underlying mechanisms remain largely unknown.…”

Sleeve gastrectomy in obese Wistar rats improves diastolic function and promotes cardiac recovery independent of weight loss

“…A SG and sham surgery were performed as previously described (13) . In brief, a SG was performed by removing the lateral portion of the greater curvature including the nonglandular stomach using an endoscopic stapling device (Endopath ETS-Flex, 45mm white load; Ethicon, Cincinnati, OH).…”

“…Anesthetized rats underwent echocardiograms as previously described (13) . Specific techniques and measurements for rat echocardiography are presented in the supplementary methods.…”

“…We recently found that a SG preserves systolic function in a diet-induced rodent model of obesity and cardiac dysfunction, independent of weight loss for approximately 50% of the rodents (13) . In this study, we tested the hypothesis that a SG will improve diastolic dysfunction independent of weight loss due to post-operative alterations in the enterocardiac axis with beneficial changes in intracellular cardiac signaling using a rodent, highfat, diet (HFD)-induced model of obesity.…”