A series of pilot clinical studies has indicated that non-invasive external stimulation of the vagus nerve alleviates disease symptoms in patients with rheumatoid arthritis (RA).

The findings, published in Bioelectronic Medicine, indicated that stimulating the vagus nerve inhibited the production of cytokines, proteins that mediate inflammation and reduce symptoms of swelling in patients with rheumatoid arthritis.

The research was carried out by scientists at the Feinstein Institute for Medical Research and the Academic Medical Center at the University of Amsterdam.

Vagus nerve stimulation (VNS) involves delivering electrical impulses to the vagus nerve, one of the cranial nerves that connects the brain to the body. VNS devices can either be implanted under the skin in a pacemaker-style device which sits on the chest, or external devices like the ones used in this study, which are held up to the neck and manually activated to deliver electrical impulses.

The RA patients enrolled in the study experienced a significant decrease in their DAS28-CRP score – a  measure of disease activity in rheumatoid arthritits – two days post-treatment, with disease activity remaining significantly reduced for seven days post-treatment. While the average DAS28-CRP score pre-treatment was 4.19, indicating a moderate level of disease activity, after treatment this fell to 3.12, indicating a low level.

Persistent improvement in visual analogue scale scores, a patient-derived measure of global health assessment, was also observed in RA patients following VNS treatment.

VNS has been used to treat a multitude of different conditions in the past, such as epilepsy, stroke and depression, but this is one of the first times it has been used to treat RA.

Feinstein Institute president and CEO Kevin Tracey said: “This clinical research suggests that non-invasive stimulation could suppress inflammation in rheumatoid arthritis patients.”

RA is a chronic inflammatory disease which causes pain, swelling and stiffness in the joints. Symptoms are traditionally mediated using both synthetic and biological antirheumatic drugs, but these can trigger a series of unpleasant side effects ranging from heartburn and stomach upset to blood clotting and even stroke.

The disease affects around 1.3 million people in the United States alone, costing tens of billions of dollars annually to treat.

Feinstein Institute professor Dr Sangeeta Chavan said: “Our primary objective was to observe if a non-invasive treatment using an external device will be effective in improving disease severity of rheumatoid arthritis that continues to plague more than one million across the country each year.

“We are pleased to observe that this novel bioelectronic treatment significantly reduces swelling and inflammation associated with RA.”