Long-Term Sympathoinhibitory Effects of Surgically Induced Weight Loss in Severe Obese Patients

Abstract

Weight loss improves insulin sensitivity and exerts sympathomodulatory effects. No data, however, are available on the effects of the weight loss induced by vertical sleeve gastrectomy on sympathetic neural drive, insulin sensitivity, and their reciprocal cross talks. In 10 severe obese hypertensives (age, 54.0±2.3 years [mean±SEM]), we measured sphygmomanometric blood pressure, heart rate, body mass index, homeostatic model assessment index, plasma leptin, muscle sympathetic nerve traffic (microneurography), and baroreflex sensitivity (vasoactive drug technique). Measurements were performed 2 to 3 days before surgery and repeated 6 and 12 months after the procedure. Ten matched hypertensive obeses not undergoing gastrectomy served as controls. Six months after bariatric surgery, a significant ( P <0.05) reduction in body mass index (−9.1±1.4 kg/m 2 ), sphygmomanometric systolic blood pressure (−10.2±4.5 mm Hg), heart rate (−11.0±2.4 bpm), homeostatic model assessment index (−3–3±1.3 AU), plasma leptin (−53.6±8.8 μg/L), and muscle sympathetic nerve traffic (−15.0±3.4 bursts/100 heart beats) was observed. The weight loss, the plasma leptin reduction, and the sympathetic inhibition were maintained after 12 months, whereas homeostatic model assessment index showed a tendency to return toward presurgery values. A significant improvement in baroreflex control of sympathetic nerve traffic was observed both 6 (+32.1%; P <0.05) and 12 months (+60.7%; P <0.01) after gastrectomy. No significant changes in the above-mentioned variables were detected in the control group. These data provide evidence that massive weight loss induced by sleeve gastrectomy triggers profound sympathoinhibitory effects, associated with a stable and significant reduction in plasma leptin levels, whereas the improvement in insulin sensitivity was attenuated with time and unrelated to the sympathoinhibition.