Increase in Ghrelin Levels After Weight Loss in Obese Zucker Rats is Prevented by Gastric Banding

Abstract

Background Gastric banding is thought to decrease appetite in addition to the mechanical effects of food restriction, although this has been difficult to demonstrate in human studies. Our aim was to investigate the changes in orexigenic signals in the obese Zucker rat after gastric banding. Methods Obese Zucker rats ( fa/fa) were submitted to gastric banding (GBP), sham gastric banding fed ad libitum (sham), or sham operation with food restriction, pair-fed to the gastric banding group (sham-PF). Lean Zucker rats ( fa/+) were used as additional controls. Body weight and food intake were daily recorded for 21 days after surgery when epididymal fat was weighed and fasting ghrelin and hypothalamic NPY mRNA expression were measured. Results Gastric banding in obese Zucker rats resulted in a significant decrease of cumulative body weight gain and food intake. Furthermore, gastric banded rats were leaner than Sham-PF, as expressed by a significantly lower epididymal fat weight. Ghrelin levels of gastric banded rats were not increased when compared to sham-operated animals fed ad libitum and were significantly lower than the levels of weight matched sham-PF rats (1116.9±103.3 g GBP vs 963.2±54.3 g sham, 3,079.5±221.6 sham-PF and 2,969.9±150.9 g lean rats, p<0.001); hypothalamic NPY mRNA expression was not increased in GBP when compared to sham-operated rats. Conclusion In obese Zucker rats, GBP prevents the increase in orexigenic signals that occur during caloric deprivation. Our data support the hypothesis that sustained weight loss observed after gastric banding does not depend solely on food restriction.

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

“…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). However, restrictive surgery, such as gastric banding, sometimes resulted in increased (Nijhuis et al, 2004;Korner et al, 2009) or unchanged (Hanusch-Enserer et al, 2003 plasma total ghrelin level after operation in humans.…”

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

“…In addition, a cross-sectional study of subjects who had undergone gastric banding 9-15 months previously found that banding patients had significantly lower plasma ghrelin levels than normoweight and obese controls [18]. A recent study of the relationship between LAGB and plasma leptin in obese Zucker rats [22] has suggested that, in a standardized system, ghrelin levels remain constant after surgery. With our study's larger subject group (n=24), assessment of acylated and total ghrelin, and multiple independent measurements of the amount of total ghrelin in each plasma sample, we aimed to decrease variation often caused by small sample size and inter-assay variability.…”

Plasma Ghrelin Modulation in Gastric Band Operation and Sleeve Gastrectomy

“…The band was fixed with two vertical stitches [22,23]. For the control group, the technique consisted of the same procedure described above except for the incision of the stomach.…”