Non-invasive Regulation of Body Weight and Metabolism by Chronic Low-Intensity Focused Ultrasound Stimulation of Vagus Nerve

As a global epidemic, obesity is often associated with metabolic dysregulation. Previous studies have shown that chronic electrical vagus nerve stimulation with an implanted electrode has the potential for obesity treatment. However, this method is invasive and has perioperative risks of surgical implantation. In this study, one non-invasive method, chronic low-intensity focused ultrasound stimulation (FUS) of the vagus nerve, was proposed to regulate body weight and key metabolic biomarkers. The study experiments were conducted on three young rat groups. They are the FUS group (cervical vagus nerve stimulation), the Sham group (FUS applied to a non-target site), and the Control group (no intervention). For each rat in both FUS and Sham groups, the FUS intervention was conducted three days per week over four weeks. After four weeks, the body composition and metabolic biomarker levels of all the rats were assessed. The results showed that the FUS-group rats had significantly lower body weight gain and fat mass during their growth stage in comparison to the Sham and Control groups. Additionally, the FUS group exhibited decreased plasma metabolic levels of insulin and leptin and an increased adiponectin level, relative to the other groups. The pilot findings suggest that the chronic low-intensity FUS of the vagus nerve might offer a promising approach to manage obesity and metabolic syndrome non-surgically and non-pharmacologically.