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Microbes & Immunity Benefit of noninvasive VNS in vaccine optimization

and single-channel recordings) has recently been shown α7nAChR nicotinic receptor, essential in the cholinergic
to provide the molecular basis of the involvement of anti-inflammatory pathway and innate immunity, has also
α7nAChRs in COVID-19 pathophysiology. Moreover, been shown, to be important for the regulation of adaptive
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in silico experiments unveiled the correlation between the immune responses at a later stage. 61,62
strength of SARS-CoV-2 variants binding to α7nAChR Actually, vagus nerve, a pivotal component of the
and their severity. SARS-CoV-2 binding to α7nAChR is microbiota-gut-brain axis, optimizes immune regulation
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likely to impair the vagus nerve activity 38,51 in addition to by influencing circadian clocks, the latter emerging
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macrophage function, ultimately disrupting cholinergic as the master regulators of immunity 64,65 and health.
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anti-inflammatory pathway, rather than solely competing Indeed, the ANS has been shown to coordinate circadian
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with Ach. Indeed α7nAChR is expressed in the vagus functions of hematopoietic stem cells, notably through
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nerve itself, thereby facilitating SARS-CoV-2 invasion and a dual cholinergic signaling. VNS is known to modulate
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subsequent detection in the vagus nerve fibers. Therefore, intrinsic biological rhythms in epileptic patients, as
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attenuating the SARS-CoV2-mediated dysregulation of one of the complications reported in trials was induced
the vagus nerve activity, with noninvasive VNS, could sleep abnormalities. Moreover, research has revealed
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lessen the severity of the infection, thereby contributing to that noninvasive auricular VNS exhibited time-varying
sufficient and satisfactory protection against SARS-CoV-2 efficiency, with circadian rhythms. This is not surprising
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in young children. since the dorsal vagal complex itself houses a local
4. Discussion network of autonomous circadian oscillators. 71,72 Thus,
cholinergic modulation of the immune system via vagus
4.1. Epidemiological and scientific issues nerve stimulation could help complement the properties
Neither previous SARS-CoV-2 infections nor serial of innate and adaptive immune memory, providing a fast,
vaccinations, including a bivalent vaccine, seem to be able broad-spectrum, specific, long-term, and self-harmless
to “markedly” protect against the Omicron subvariants. host defense (Figure 1).
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Moreover, monoclonal antibodies capable of neutralizing 4.2. Ethical issues
the original Omicron variant are largely inactive against
the new emerging subvariants. In addition, vaccine COVID-19 vaccines do not either completely prevent
responsiveness in minors being afflicted with childhood vaccines from SARS-CoV-2 infection or obstruct human-
diseases could be affected by their innate and adaptive to-human transmission, with the degree of protection they
might have against long COVID-19 symptoms remaining
immunity. 56,57 On the contrary, noninvasive VNS presents a controversial. Besides, because of molecular mimicry
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marked efficiency in mitigating the inflammatory response existing between SARS-CoV-2 and human components,
triggered by several recurrent pathogens and is thought to
be safe, even for newborns, but has not been established
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as a preventive treatment for COVID-19 or other viral
infections yet.
It may be time to consider noninvasive VNS as a new
paradigm in managing infectious diseases, to optimize
reciprocally innate and adaptative immunity without
enhancing autoimmunity. Indeed, for centuries, the
molecular mechanisms by which hematopoietic cells initiate
and maintain host immunity are given much emphasis in
the realm of immunology, which are classically divided
into innate (rapid but unspecific immunity) and adaptive
immunity (slower but specific defenses). Nevertheless,
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in the last two decades, this compartmentalized concept
of immunity has been challenged by the discovery of an
innate immune memory named “trained immunity,” as
innate immunity also turned out to be modulated by
previous encounters with pathogens. Simultaneously, Figure 1. Noninvasive vagus nerve stimulation (VNS) reciprocally
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Kevin Tracey and his team found that vagus nerve enhances trained immune and adaptive immunity. Noninvasive VNS
could help prevent severe infections, without augmenting autoimmunity,
and cholinergic signaling play a pivotal role in neural in populations with low high rate variability, by modulating the
regulation of immunity. Interestingly, activation of microbiota-gut-brain axis.
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Volume 1 Issue 1 (2024) 53 doi: 10.36922/mi.2598