Novel gastric sleeve magnetic implant: safety and efficacy in rats

Background: The prevalence of obesity is growing worldwide and has reached epidemic proportions. Vertical sleeve gastrectomy, which requires irreversible removal of gastric tissue, is considered an effective weight loss treatment of severe obesity. The aim of the present study was to evaluate the feasibility of a reversible gastric sleeve magnetic implant that mimics the vertical sleeve gastrectomy without the gastrectomy for weight loss in a group of normal and obese rats. Methods: A group of Zucker fatty rats either underwent surgical implantation or a sham operation and were followed up for 6 weeks. Also, a group of Wistar rats underwent surgical implantation for 6 weeks, followed by surgical implant removal at 6 weeks, and recovery for an additional 4 weeks. Food intake and body weight were monitored after surgery to determine the efficacy of the device. A histologic examination for all rats was made to evaluate the change in the gastric wall in response to gastric sleeve magnetic implantation. Results: The implanted Zucker fatty and Wistar rats showed a statistically significant decrease in food intake and weight gain rate compared with the sham-operated rats (approximately 3%/wk of body weight loss in the treated group). Moreover, the decrease in the weight gain rate was sustained for 4 weeks after removal of the magnetic implant. The histologic evidence revealed an inflammatory mononuclear cell infiltration and mild fibrosis and hyperplasia of blood vessels, as expected for any implant. No significant structural damage, tissue ischemia, hemorrhage, or necrosis was found in the gastric wall. Conclusion: Our results have shown that the device is feasible in rats, results in effective weight loss, and can be easily removed. These findings, along with the lack of the need for resection of the native stomach, provide a compelling basis for additional development of the device in large animal models.