tVNS and obesity-related inflammation: a prospective sham-controlled randomized crossover study protocol

Area of Science:

• Neuroscience
• Immunology
• Metabolic Disorders

Background:

• Obesity and overweight are linked to chronic low-grade inflammation (metaflammation) impacting mood and motivation.
• The cholinergic anti-inflammatory pathway (CAIP), targeted by vagus nerve stimulation (VNS), may modulate these processes.
• Non-invasive transcutaneous VNS (tVNS) effects on inflammation require further investigation, especially in home-based, long-term obesity studies.

Purpose of the Study:

• To assess the effects of daily home-based tVNS on inflammation, mood, and motivation in individuals with elevated BMI.
• To investigate the potential of tVNS to modulate obesity-related metaflammation and associated mental symptoms.
• To provide evidence for the efficacy of tVNS as a complementary therapy for overweight and obesity.

Main Methods:

• A single-blind, randomized crossover study involving 60 participants (BMI 27-35 kg/m²) self-administering high- and low-intensity tVNS daily for 14 days each, with a 7-day washout.
• Assessment of peripheral (cytokines, immune cells) and central inflammation (diffusion-weighted imaging), motivation (effort allocation task during fMRI), and mood.
• Daily ecological momentary assessments of mood and food choices during stimulation phases, analyzed using mixed-effects models.

Main Results:

• This section is not applicable as the study is ongoing and results are not yet available.

Conclusions:

• The study employs a 14-day home-based tVNS protocol with daily assessments to evaluate mid-term effects on inflammation, mood, and motivation.
• A multimodal design integrating peripheral and central inflammatory markers with behavioral outcomes will offer robust evidence on tVNS efficacy.
• Findings may elucidate the link between obesity, inflammation, and depressive symptoms, guiding future VNS research for obesity management.