Treatment Of Obesity By Endoscopic Injection Of Botulinum Toxin A Into The Gastric Gall

Background and aims:Obesity has reached epidemic proportions in China and worldwide. Botulinum toxin A (BTX-A) is a powerful inhibitor of muscular contractions in both striated and smooth muscles. Behavioral or dietary interventions have not resulted in significant or sustained decrease in BMI for obese children and adolescents, and Surgical treatments may have severe complications. A series of animal experiments were performed which showed that intra-muscular injections of BTX-A in the gastric wall of normal-weight rats significantly reduced their food intake and body weight in rats that had received BTX-A. The purpose of this study was to observe the safety and efficacy of endoscopic injections of BTX-A into the gastric wall in obese patients.Methods:19 obese patients (body mass index 28.6-47.12kg/m2) were randomized into the groupⅠ(200U BTX-A injected) or the groupⅡ(300U BTX-A injected).20 puncture sites were selected in the gastric wall including the antrum, the gastric body and gastric fundus. Food-intake, body weight, BMI, waistline, hip circumference and electrogastrogram were recorded and gastric emptying time was determined by modified 13C-octanoate breath test before treatment and 1 week,4 weeks and 12 weeks after treatment. Blood samples were obtained at the same time except at 1 week after the injection for the tests of Chol, TG, LDL, HDL, insulin, leptin, motilin, PYY and ghrelin levels. Repeated measure ANOVA was used to analyze the changes after the treatment and the difference between the two groups by SPSS 17.0. Food-intake was analyzed by t-test. The threshold level of significance was P<0.05.Results:Only 19 patients completed follow-up. Both groups showed significant body weight reduction (from 98.47±24.48kg to 93.69±24.52kg) and BMI decrease (from 34.91±5.89 kg/m2 to 33.03±5.91 kg/m2) (P<0.05) with the waistline and hip circumference decreasing. The gastric emptying time were longer than before treatment, especially significant at 1 week and 4 weeks (P<0.05). Serum TG levels decreased after 12 weeks, but no significant changes were found of cholesterol, LDL, HDL, insulin and motilin levels after the treatment. A significant decrease in fasting ghrelin levels of all 19 obese patients was found after BTX-A administration 4 weeks later, and PYY levels decreased 12 weeks later (P<0.05). No difference between the two groups was observed. No adverse effects and severe complications were observed.Conclusion:Endoscopic multi-punctures of BTX-A including the fundus injection for simple obese patients may decrease body weight and BMI by delaying the gastric emptying time and reducing food-intake. The effect of BTX-A on ghrelin levels may also be involved in the reduction of appetite. The relationship between the dose of BTX-A and the effect of weight loss needs further investigation.