Meal suppression of circulating ghrelin is normalized in obese individuals following gastric bypass surgery

Abstract

Objective: It has been proposed that the success of maintained weight loss in morbidly obese subjects following Roux-en-Y gastric bypass (RYGBP) surgery depends on inappropriately low circulating concentrations of the appetite-stimulating peptide ghrelin, being unresponsive to food intake. In this study, this hypothesis was examined. Design: Cross-sectional study with repeated blood samples in 40 subjects after 14 h of prolonged overnight fasting followed by a standardized mixed meal (770 kcal). Subjects: Twenty men and 20 women were included: 10 middle-aged morbidly obese (body mass index (BMI) 43.973.3 kg/ m 2 ), 10 middle-aged subjects who had undergone RYGBP at the Uppsala University Hospital (BMI 34.775.8 kg/m 2 ), 10 middleaged non-obese (BMI 23.572.2 kg/m 2 ) and 10 young non-obese (BMI 22.771.8 kg/m 2 ). Measurements: Ghrelin, glucose and insulin levels were analysed pre-and postprandially. Results: In the morbidly obese, ghrelin concentrations were lower in the morning than in the RYGBP group and did not change following the meal. In the RYGBP group, fasting ghrelin levels fell after meal intake and showed similar suppression as both agematched and young non-obese controls. The RYGBP surgery resulted in an increased meal-induced insulin secretion, which was related to the degree of postprandial ghrelin suppression. Conclusion: The present study demonstrates low circulating concentrations of ghrelin and blunted responses to fast and feeding in morbidly obese subjects. Marked weight reduction after RYGBP at our hospital is followed by a normalization of ghrelin secretion, illustrated by increased fasting levels compared to the preoperative obese state and regain of meal-induced ghrelin suppression.

The Effect of Laparoscopic Gastric Banding Surgery on Plasma Levels of Appetite-Control, Insulinotropic, and Digestive Hormones

“…However, decreased appetite after LAGB could be caused by altered mealtime changes in ghrelin, as has been reported for RYGB [43]; this hypothesis warrants future study. Although PP has been shown to inhibit appetite and food intake [45], our findings do not support a role for PP in LAGB-induced weight loss, consistent with data from studies on other bariatric procedures [26,27].…”

“…For the study population as a whole, the median age at the time of surgery was 46.6 (IQR 34.5-50.6) years, and the median BMI was 43 Table 1). The continued decrease in leptin levels between 6 and 12 months after surgery was not significant ( p=0.31).…”

Effects of Laparoscopic Gastric Band Applications on Plasma and Fundic Acylated Ghrelin Levels in Morbidly Obese Patients

“…Schindler et al [8] showed an increase in fasting ghrelin accompanied by a paradoxical decrease in hunger 6 months after LAGB, thus suggesting that weight loss is independent of circulating ghrelin and relies on changes in eating behavior induced by gastric restriction. The decreased appetite after LAGB could be caused by altered mealtime changes in ghrelin, as has been reported for RYGB [44]. Since only fasting plasma samples were obtained, we did not examine whether LAGB affects mealtime changes in acylated ghrelin and insulin levels.…”

Ghrelin Gene Products and the Regulation of Food Intake and Gut Motility

“…Likewise, plasma total ghrelin and obestatin levels were decreased after Roux-en-Y gastric bypass or microgastric bypass (Stenström et al, 2006) in rats. Most importantly, meal suppression of circulating total (Korner et al, 2006;Engström et al, 2007) and acyl (Korner et al, 2005(Korner et al, , 2006 ghrelin was normalized in obese persons after gastric bypass surgery. On the other hand, gastric banding surgery prevented the increase of plasma total ghrelin level after weight loss in obese Zucker rats, which supported the hypothesis that sustained weight loss observed after gastric banding did not depend solely on food restriction (Monteiro et al, 2007).…”

“…Therefore, the assumption that systemic total ghrelin levels reflect acyl ghrelin secretion should be made with caution (Gauna et al, 2007). For instance, fasting plasma total ghrelin (Cummings et al, 2002a;English et al, 2002;Rigamonti et al, 2002;Shiiya et al, 2002;Erdmann et al, 2005;Korner et al, 2005Korner et al, , 2006le Roux et al, 2005b;Engström et al, 2007;Guo et al, 2007;Vicennati et al, 2007;Huda et al, 2009;), des-acyl ghrelin (Rodríguez et al, 2009), and obestatin (Guo et al, 2007;Nakahara et al, 2008) concentration were lower in obese than lean subjects, whereas acyl ghrelin concentration was higher in obese persons (Rodríguez et al, 2009). In addition, obese persons showed lower expression of GHS-R in omental adipose tissue (Rodríguez et al, 2009).…”