Pulse Width-Dependent Effects of Intestinal Electrical Stimulation for Obesity: Role of Gastrointestinal Motility and Hormones.

Abstract

The goals of this experiment were to study therapeutic potential of intestinal electrical stimulation (IES) for obesity, its mechanisms involving gastrointestinal motility and hormones, and role of pulse width in diet-induced obese rats. In a 4-week study, rats equipped with one pair of electrodes at the duodenum were assigned to receive either a sham or IES of varied pulse widths in a sequential way. Food intake was measured daily and body weight measured weekly. Blood samples were collected for the measurement of glucagon-like peptide-1 (GLP-1). Solid gastric emptying (GE) and small bowel transit (SIT) tests were performed at the end of the experiment. The results of the study were as follows: (1) Daily food intake, not affected by IES of 0.3ms, was pulse width-dependently reduced by 1.9g with 1ms and by 5.7g with 3ms. Accordingly, body weight was pulse width-dependently reduced by 2.4g with 1ms and by 12.8g with 3ms compared to a gain of 5.6g in sham. (2) GLP-1 level was elevated by both 0.3 and 3ms at 15min, but was elevated only with 3ms at 60min. (3) GE was delayed to 52.3% by IES of 3ms but not 0.3ms, compared to that at 64.4% with sham IES. (4) Compared to the geometric center of 7.0 with sham IES, SIT was accelerated by 3ms to 7.8 but not by 0.3ms. IES pulse width-dependently reduces food intake and body weight, attributed to the delay of gastric emptying and the acceleration of small bowel transit, as well as the enhancement of GLP-1 secretion.