The Decrease in Plasma Ghrelin Concentrations following Bariatric Surgery Depends on the Functional Integrity of the Fundus

Background: Gastric bypass surgery, which involves the production of a reduced stomach pouch,has been shown to markedly suppress circulating ghrelin concentrations. Since bypassing the ghrelin-producing cell population may be relevant to the disruption of fundic-derived factors participating in food intake signaling, the effect of weight loss induced by either adjustable gastric banding (AGB), Roux-en-Y gastric bypass (RYGBP) or biliopancreatic diversion (BPD) was studied. Methods: 16 matched obese patients 35.0 + 2.4 years; initial body weight 124.8 ± 5.7 kg; body mass index (BMI) 47.1 ± 2.2 kg/m²] in whom similar weight loss had been achieved by either AGB (n=7), RYGBP (n=6) or BPD (n=3) were studied. Blood was obtained for biochemical and hormonal analyses. Body composition was assessed by air-displacement-plethysmography. Results: Comparable weight loss (AGB: 26.1 ± 5.1 kg; RYGBP: 32.1 ± 5.0; BPD: 31.7 ± 6.1; P=NS) and decrease in percentage body fat (AGB: 10.0 ± 1.5%; RYGBP: 14.2 ± 2.8; BPD: 10.3 ± 1.0; P=NS) induced by bariatric surgery exerted significantly different (P=0.004) effects on plasma ghrelin concentrations, depending on the surgical procedure applied (AGB: 480 ± 78 pg/ml; RYGBP: 117 ± 34; BPD: 406 ± 86). Without significant differences in BMI, body fat, glucose, triglycerides, cholesterol, insulin and leptin levels, patients who had undergone the RYGBP exhibited statistically significant diminished circulating fasting plasma ghrelin concentrations compared with the other two bariatric techniques which conserve direct contact of the fundus with ingested food (P=0.003 vs AGB and P=0.020 vs BPD). Conclusion: Fasting circulating ghrelin concentrations in patients undergoing diverse bariatric operations depend on the degree of dysfunctionality of the fundus.