Effects of intramural administration of Botulinum Toxin A on gastric emptying and eating capacity in obese patients

BackgroundIntraparietal gastric administration of Botulinum Toxin A has been studied in open trials to induce satiety and increase weight loss of obese patients with contradictory results. In previous studies only the antrum was the target for Botulinum Toxin A, whereas the fundus, which exerts important activity on gastric accommodation, was excluded. In this study we report the effects of injection into both gastric regions on solid gastric capacity and emptying of the stomach.Materials and methodsIn this study we extended our previous investigations to include 30 obese patients who received Botulinum Toxin A (120 U into the antrum and 80 U into the fundus) or saline by intraparietal endoscopic injection. The two groups were homogeneous for age, gender, body weight and body mass index. Body weight and body mass index, solid gastric emptying (T1/2 and Tlag at the octanoic acid breath test) and maximal gastric capacity for solids (kcal) were determined before injection and 2 months later. The results were expressed as mean values (S.E.M.). t-Test or Wilcoxon test was used for statistical analysis, p < 0.05 being considered significant.ResultsBoth treatments induced a significant reduction of body weight and body mass index but Botulinum Toxin A exerted a significantly greater effect (body weight −11.8 ± 0.9 kg vs. −5.5 ± 1.1 kg, p < 0.0002; body mass index −4.1 ± 0.2 vs. −2.2 ± 0.4, p < 0.001). The maximal gastric capacity for solids was also reduced by both Botulinum Toxin A and placebo, the former being significantly more effective (679 ± 114 kcal vs. 237 ± 94 kcal, p < 0.008). Botulinum Toxin A also significantly increased T1/2 from 83.4 ± 3.9 to 101.6 ± 9.9 min, p < 0.03) but Tlag was unchanged. Placebo had no effect on either of these parameters.ConclusionsOur results demonstrated that Botulinum Toxin A makes weight loss easier in obese patients. It acts by increasing the solid gastric emptying time and reducing the solid eating capacity of the stomach.