Changes of Body Weight and Plasma Ghrelin Levels after Gastric Banding and Gastric Bypass

Abstract

STOECKLI, ROLF, ROBIN CHANDA, IGOR LANGER, AND ULRICH KELLER. Changes of body weight and plasma ghrelin levels after gastric banding and gastric bypass. Obes Res. 2004;12:346 -350. Objective: Ghrelin is an enteric peptide with strong orexigenic and adipogenic effects. Plasma ghrelin levels are decreased in obese subjects but increase after weight loss; this increase is not observed after Roux-en-Y gastric bypass (RYGB). Prospective and comparative data after adjustable silicone gastric banding (ASGB) have not been reported previously. Research Methods and Procedures:Overnight fasting plasma ghrelin concentration was measured in morbidly obese subjects at baseline and 3, 6, 12, and 24 months after ASGB (n ϭ 8) or RYGB (n ϭ 5) and in nonoperated controls (n ϭ 7). Results: After RYGB, body weight (BW) decreased by 29.5 Ϯ 5.5 kg (mean Ϯ SE, p Ͻ 0.001), whereas plasma ghrelin failed to increase significantly (ϩ167 Ϯ 119 pg/mL, not significant). In contrast, after ASGB, BW decreased less (by 22.8 Ϯ 5.9 kg; p Ͻ 0.001), and plasma ghrelin significantly increased by 377 Ϯ 201 pg/mL (p ϭ 0.025). Neither BW nor plasma ghrelin changed in nonoperated controls. Plasma leptin decreased in both operated groups (similarly p Ͻ 0.05) but not in nonoperated controls. Plasma growth hormone and insulin-like growth factor 1 were not correlated with changes in plasma ghrelin concentrations.Discussion: Plasma ghrelin levels failed to increase during substantial weight loss after RYGB, but did increase in response to lesser weight loss after ASGB. These findings suggest that the plasma ghrelin response after weight loss is impaired after exclusion of major parts of the stomach and the duodenum (RYGB), and the smaller long-term weight loss after ASGB compared with RYGB may be due, at least in part, to an absent increase in plasma ghrelin after RYGB.

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

“…Fasting ghrelin levels have been found to increase 2 years after vertical banded gastroplasty [38] and in patients who attained 20% body mass index (BMI) loss [39]. Likewise, in obese patients 6 months [9,16,18,19,40,41], 12 months [17,19,40], and 24 months [38,40] after being submitted to adjustable gastric banding, fasting ghrelin levels have been shown to increase, similarly to diet induced weight loss, although the increase in ghrelin levels was greater after surgery than after dietinduced weight loss, and this could be explained by the higher amount of weight loss achieved with surgery. Furthermore, postoperative ghrelin levels were also reported as not being different from those of non-operated BMImatched patients [9].…”

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

“…They hypothesized that the suppressed ghrelin levels contribute to the weight-reducing effect of the surgery. Leonetti et al 17 and Tritos et al 18 also reported lower ghrelin values in operated patients compared with matched controls, and in patients studied pre-and postoperatively decreased ghrelin levels 19,20 or unchanged levels 21 have been shown compared with the preoperative state. In contrast, we observed increased ghrelin levels in 40 out of 53 patients and in 60 out of 66 patients 6 and 12 months after gastric bypass surgery, respectively.…”

The vagus nerve, food intake and obesity

“…Cummings and colleagues had hypothesized that ghrelin cells in the gastric mucosa may eventually cease to secrete ghrelin, as they are constantly stimulated by an empty stomach (override inhibition hypothesis) (Cummings et al, 2004). However, some doubt is cast on this explanation by reports of unchanged (Stoeckli et al, 2004), or even increased (Holdstock et al, 2003) ghrelin levels after RYGB, and by the observation in rats, that postprandial ghrelin suppression does not depend on nutrients in the stomach, but on nutrients in the duodenum and proximal jejunum (Williams et al, 2003a). Reflux of nutrients from the bypass limb into the proximal jejunum could thus still trigger prandial ghrelin suppression, rendering the override inhibition hypothesis doubtful.…”