BACKGROUND: Obesity is a common metabolic disorder affecting nearly one-third of the global population. Emerging evidence indicates that the microbiota-gut-brain axis plays a key role in the pathogenesis of obesity. Transcutaneous auricular vagus nerve stimulation (taVNS), a non-invasive neuromodulation technique, may modulate brain function and gut microbiota via vagal pathways. This study aims to evaluate the short-term efficacy of taVNS in reducing body weight in patients with obesity and to explore its underlying mechanisms by assessing changes in neural activity and gut microbial composition.
METHODS: This single-center, randomized controlled trial will enroll 74 patients with obesity, who will be randomized in a 1:1 ratio to receive either taVNS (electrical stimulation delivered to the left cymba conchae) or sham taVNS (stimulation at the tail of the helix). The primary outcome will be the percentage change in body weight from baseline to Week 12. Secondary outcomes will include anthropometric measures such as changes in body mass index (BMI), waist circumference, hip circumference, body fat percentage, and visceral fat area. Clinical evaluations will be conducted using validated instruments, including the Impact of Weight on Quality of Life-Lite (IWQOL-Lite), Perceived Stress Scale (PSS), Hamilton Depression Rating Scale (HAMD), Dutch Eating Behavior Questionnaire (DEBQ), International Physical Activity Questionnaire (IPAQ), and the Fatigue Scale-14 (FS-14). To investigate modulation of the microbiota-gut-brain (MGB) axis, assessments will include serum brain-gut peptides, gut microbiota composition, and functional magnetic resonance imaging (fMRI). Adverse events will also be systematically monitored throughout the study period.
DISCUSSION: This study will preliminarily validate the clinical efficacy of taVNS for obesity. And by integrating measures such as gut peptides, microbiota profiling, and brain imaging, it seeks to link therapeutic effects with microbiota-gut-brain axis modulation. The findings may support taVNS as a safe, non-pharmacological approach for obesity management and inform future neuromodulation-based strategies.
TRIAL REGISTRATION NUMBER: ITMCTR2024000518. http://itmctr.ccebtcm.org.cn/zh-CN/Home/ProjectView?pid=d4ae9741-2788-433a-9242-a5fe78929bce.
