Food intake and body weight responses to intermittent vs. continuous gastric electrical stimulation in diet-induced obese rats

Background: Gastric electrical stimulation (GES) has recently been introduced as a potential therapy for the treatment of obesity. The main challenge for the new generation of devices is to achieve desired clinical outcomes at a suitably low level of energy consumption. The aim of this study is to compare the effectiveness of GES with continuous and intermittent duty cycles in reducing food intake and body weight in diet-induced obesity-prone rats. Methods: In macro duty cycle experiment, 40 rats were divided into groups to receive a sham GES, continuous GES, or intermittent GES (15 min On-45 min Off or 15 min On-15 min Off) for 28 days. In micro duty cycle experiment, 18 rats received cross-over treatment of continuous stimulation, 60 % time cycle or 40 % time cycle. Food intake, body weight, gastric emptying and ghrelin level were measured to evaluate the effect of different GES. Results: GES with macro duty cycle intensity-dependently reduced mean daily food intake increase by 18.6, 10.2 and -6.0 % compared to 42.7 % with sham GES and body weight gain by 6.1 %, 3.4 and -0.8 % compared to 5 % with sham GES. Daily food intake decreased with increasing micro duty cycle intensity, averaging 16.5, 15.6 and 13.7 g/day under 40 % cycle, 60 % cycle and continuous stimulation respectively. Gastric emptying was intensity-dependently delayed by GES. GES has no effect in modulating plasma ghrelin level. Conclusions: GES energy-dependently reduces food intake, body weight and gastric emptying. Peripheral modulation of plasma ghrelin level is not related to the GES effects.