Intragastric injection of botulinum toxin for the treatment of obesity. Where are we?

Abstract

Obesity has reached epidemic proportions particularly in western countries. Most non-surgical treatments of this condition are disappointing. Since 2005, several studies evaluating the effect of Botulinum Toxin type A (BT-A) in gastric antrum by means of endoscopy for the treatment of obesity have been published. This treatment modality was based on the observation that gastric injection of BT-A in laparatomized rats induced a significant reduction of food intake and body weight. Nowadays, 6 studies have been published yielding conflicting results. Differences in selection of patients, doses of BT-A, method of administration of the toxin and instruments of evaluation of some parameters among these studies may be the cause of divergent results. We discuss herein some important features of these studies pointing out on differences among them. At the same time, based on the knowledge of physiological characteristics of normal and abnormal gastric function related with feeding, we discuss the probable causes of failure observed in these trials. Finally, we give some guidelines concerning the way that future research in this field may follow, not without calling attention to disadvantages of this treatment.

Current endoscopic techniques in the treatment of obesity

“…Tolerance (Table VIII) All documented series coincide in stating that it is safe, well tolerated treatment without significant side effects, both gastric and neuromuscular (71), regardless of dose and gastric place of BTA administration (62,64,(66)(67)(68)72).…”

Endoscopic Treatment of Obesity

“…In one study (64), the toxin was injected both into the antrum and the gastric fundus. In the other studies, it was only injected in the antrum, which likely explains the differences in results that were observed (66). Additional studies are needed to assess the role of botulium toxin in the treatment of obesity.…”

“…A study published two years later (60) showed that intragastric injection of botulinum toxin was safe and well tolerated. The published studies (60)(61)(62)(63)(64)(65)(66), however, have reported conflicting results. One study performed by an Italian group (64) reported a delay in gastric emptying, early satiety and body weight reduction.…”

Botulinum Toxin A for Controlling Obesity

“…Subsequently, similar findings were confirmed by Coskun et al in obese rats [13]. In humans, injections with BoNT-A has led to conflicting results, probably coming from differences in the sites of administration (antrum and/or fundus region), the doses of the toxin, and patient selection [14]. Very recently, in a meta-analysis and meta-regression of eight studies, Bang et al analyzed a total of 115 patients (79 treated vs. 36 placebo).…”