Vagus Nerve Stimulation: A Potential Adjunct Therapy for COVID-19

The pathophysiology of COVID 19 includes an excessive inflammatory phase called “cytokine storm” which is associated with high mortality. Clinical patterns similar to those in sepsis have been documented in COVID-19 patients. Excessive inflammation in COVID-19 leads to multiple organ dysfunction. Several therapeutics targeting inflammatory responses are currently being used in treating COVID 19.

However, non-drug therapeutic strategies targeting inflammatory and immunological processes may be useful for reducing COVID-19-induced complications and improving patient outcomes. It is hypothesized that vagus nerve stimulation (VNS) can be a potential adjunct therapy for COVID-19. The vagus nerve is composed of afferent sensory fibres carrying information from the periphery to the brain. Within the central nervous system, the vagus primarily projects to the nucleus of the solitary tract (NTS), releasing excitatory neurotransmitters (glutamate and aspartate), an inhibitory neurotransmitter (gamma-aminobutyric acid), acetyl-choline, norepinephrine, and neuropeptides. The efferent and afferent fibres of the vagus nerve play a role in maintaining cardiovascular homeostasis and in modulating inflammation.

The autonomic nervous system regulates the production of cytokines leading to the release of anti-inflammatory glucocorticoid hormones. Vagal efferent fibres also release acetylcholine (Ach), which, by interacting with α7subunit-containing nicotinic receptors of macrophages, and dendritic cells, inhibit the release of proinflammatory cytokines. It is found that electrical stimulation of the vagus nerve attenuates inflammation in a variety of pathological conditions with few side effects. These findings suggest that VNS could be a promising adjunctive therapy targeting the inflammatory pathways in COVID-19 patients. Vagus nerve stimulation is a safe therapy. VNS reduced complications of COVID-19 in two patients. Studies evaluating the efficacy of non-invasive VNS in COVID-19 patients are now ongoing using the gammaCore® non-invasive vagal nerve stimulation device.

Ref Link: doi: 10.3389/fmed.2021.625836