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

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.

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.

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.

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.