Thread by @drkohilathas

Vagus nerve stimulation

An anti-inflammatory, cardioprotective, autonomic dysfunction regulating, brain plasticity-inducing, memory-boosting, analgesic, anti-epileptic, fear-diminishing, anti-metastasis, and motor and sensory rehab-aiding therapeutic.

A THREAD 🧵

The vagus nerve is the autonomic nervous system's longest nerve. It sends parasympathetic fibres to all of our organs (except the adrenal glands), from the neck down to a portion of our small intestine, allowing us to "rest and digest."

It also helps regulate our heartbeat and is involved in other biological processes such as sweating and speaking.

One way to activate the vagus nerve is via deep breathing; another way is to electrically stimulate it.

Vagus nerve stimulation (VNS) has been used as a treatment since 1997 to control seizures in epilepsy patients. Here, a neurostimulator is implanted in the chest to stimulate the vagus nerve.

It has now been accepted that non-invasive VNS of the vagus nerve branch running around the left external ear (described as transcutaneous VNS) produces similar effects to invasive VNS.

This highlights the potential benefits of using non-invasive VNS, similar to the application of invasive VNS in previous studies. And the benefits of VNS seem to be manyfold.

A 2019 study involving rats with severed nerves demonstrated that those who received rehab and bursts of closed-loop VNS (CL-VNS) had significantly larger areas of the brain related to movement (motor cortex) that evoked specific movements than those that didn’t have VNS.

The rats that received rehabilitation and CL-VNS together also performed better than their counterparts who had vagus nerve stimulation after rehab.

pubmed.ncbi.nlm.nih.gov/31857587/

In addition to reversing the maladaptive changes in the structure and function of the brain (a term called “plasticity”) arising from nerve injury...

the rats also displayed enhanced recovery of motor and sensory function without any observable changes in the peripheral nerves or muscles, as well as a reduction in pain.

My interest in VNS began when researching ways to help my uncle who has a spinal cord injury. I've written about ways to improve the nervous system here 👇🏾

drkohilathas.gumroad.com/l/optimiseyour…

Pairing VNS with rehab may prove useful in treating a wide range of neuro disorders.

One study that delivered VNS every 10 seconds for 30 minutes to stroke patients alongside rehab showed a sustained improvement in upper-limb impairment and functional measures at 1 year.

pubmed.ncbi.nlm.nih.gov/30355189/

VNS paired with sounds have shown to drive the reorganisation in the auditory cortex (this has shown to help with tinnitus).

pubmed.ncbi.nlm.nih.gov/25689839/

Delivery of VNS after behavioural experience can enhance memory retention.

nature.com/articles/nn019…

VNS paired with extinction training was effective at reducing a specific fear memory (and may be helpful in those who suffer with conditions like PTSD).

pubmed.ncbi.nlm.nih.gov/23245749/

High-frequency (80 Hz) non-invasive VNS has also been shown to improve the sense of smell (olfactory function) in healthy adults.

ncbi.nlm.nih.gov/pmc/articles/P…

The benefits of VNS are not only restricted to the neurological realm, either. The most common autonomic mechanism behind numerous arrhythmias and conditions like POTS is likely an imbalance of the symp and parasympathetic nervous systems, and VNS here may bring about balance

pubmed.ncbi.nlm.nih.gov/25164906/

Another study showed that low-level transcutaneous VNS (20 Hz) for one hour a day for six months reduced the median AF burden by 85% in the active arm compared to the control arm.

ncbi.nlm.nih.gov/pmc/articles/P…

In a study of dogs with heart attacks, researchers discovered that persistent transcutaneous low-level VNS reduced the inducibility of another form of arrhythmia called ventricular tachycardias, as well as improving how the heart remodelled after injury.

ncbi.nlm.nih.gov/pmc/articles/P…

It must be noted however that other studies have shown VNS enhancing arrhythmias like AF depending on the strength of stimulation.

pubmed.ncbi.nlm.nih.gov/28862330/

With regards to POTS, one case study presented a 29-year-old lady with intractable epilepsy and POTS who was treated for seizures with an implanted VNS device, and her POTS symptoms subsided and her tilt table test became normal with VNS therapy.

seizure-journal.com/article/S1059-…

One meta-analysis of 1,263 patients showed that there was a high grade of evidence indicating that VNS improved the functionality and quality of life of those with severe heart failure too.

frontiersin.org/articles/10.33…

Before you scroll further, if you like my threads, then you may find if of interest to know that I source the information for it from my recently released book.

People are seeming to enjoy it!

Click on the link to find out more 👇🏾 callingouttheshots.xyz

Communication between the immune system and the brain is critical for inflammation regulation. The vagus nerve plays a major role in both sensing and acting on inflammation, acting as a highway between the brain and the immune system.

For example, peripheral administration of endotoxin or IL-1β causes afferent vagus nerve activation, and in mice with endotoxemia, VNS reduces local and serum proinflammatory cytokine levels, and acetylcholine inhibits the release of TNF, IL-1, and IL-18 from macrophages.

Interestingly, vagus nerve fibres sending information to the brain appear to be important for relaying information about immune status to the brain when proinflammatory cytokines are present at fairly low levels.

pubmed.ncbi.nlm.nih.gov/11247812/

Vagus nerve signalling has been linked to attaining and maintaining weight loss after bariatric surgery.

ncbi.nlm.nih.gov/pmc/articles/P…

Unpublished also indicate that vagus nerve stimulation suppresses insulin resistance in rodents.

ncbi.nlm.nih.gov/pmc/articles/P…

In one study of 110 participants with COVID-19, the use of non-invasive VNS (25 Hz) showed to lead to significant reductions in levels of inflammatory markers, “specifically CRP and procalcitonin.”.

The authors go on to state...

ncbi.nlm.nih.gov/pmc/articles/P…

“Because nVNS has multiple mechanisms of action that may be relevant to COVID-19, additional research into its potential use earlier in the course of COVID-19 and its potential to mitigate some of the symptoms associated with post-acute sequelae of COVID-19 is warranted.”

Other than acute COVID-19 infection, VNS has also shown potential in helping with symptoms of long COVID, this may be because long COVID possesses an element of autonomic dysfunction.

In one study, transcutaneous VNS on settings 25Hz, 500us pulse width, tonically on for 1 hour, twice per day, 6 days per week for 4 weeks, showed to have mild to moderate effect in reducing mental fatigue symptoms in a subset of individuals.

researchsquare.com/article/rs-171…

Dosage: One review noted that with regards to transcutaneous VNS, various studies used a range of pulse widths of 20–500 μs; frequencies of 1–30 Hz; on/off times of 0.5 s – 30 min ON/30–270 s OFF; times administered ranging from 6 min – 9 months; and a current of 0.13–50 mA.

ncbi.nlm.nih.gov/pmc/articles/P…

The vagus nerve is involved in cancer spread.

Patients with ulcers who have had a vagotomy have been shown to die from cancer more frequently than do those who have not had this procedure, and vagotomy attenuates tumour-induced anorexia and leads to enhanced tumour progression.

sciencedirect.com/science/articl…

Vagal nerve activity has shown to predict overall survival in metastatic pancreatic cancer, mediated by inflammation.

"higher initial HRV was sig correlated with lower risk of death, independent of confounders including age and cancer treatments."

sciencedirect.com/science/articl…

Heart rate variability (HRV) is the physiological phenomenon of variation in the time interval between heartbeats.

Vagal tone” is a clinical measure believed to indicate overall levels of vagal activity. It is measured indirectly through the HRV.

journals.physiology.org/doi/abs/10.115…

Vagal nerve activity is associated with pro-inflammatory and anti-viral factors in breast cancer.

sciencedirect.com/science/articl…

"Thus, we conclude that individuals with higher HRV and advanced coping mechanisms seem to have a better prognosis in cancer progression. HRV appears to be a useful aspect to access the general health status of cancer patients."

pubmed.ncbi.nlm.nih.gov/29896113/

"The results support the hypothesis that perturbations in nonlinear dynamical patterns of HRV predict increased GC severity."

nature.com/articles/s4159…

"The current evidence indicates a predictive value of HRV in the survival of patients with cancer and higher vagal nerve activity might predict longer survival"

sciencedirect.com/science/articl…

"initially advanced tumor stages of CRC or PC predicted higher tumor marker levels at follow-up than did early stages. However, this occurred only in patients with low, not high, vagal activity (HRV)"

pubmed.ncbi.nlm.nih.gov/25001652/

"These results provide a rationale to expect that vagus nerve stimulation, in combination with conventional cancer treatments, may improve the prognosis of cancer patients by promoting anticancer immunity."

sciencedirect.com/science/articl…

"Vagal Nerve Activity Predicts Prognosis in Diffused Large B-Cell Lymphoma and Multiple Myeloma"

mdpi.com/2077-0383/12/3…

"Activation of vagus nerve by semapimod alters substance P levels and decreases breast cancer metastasis"

pubmed.ncbi.nlm.nih.gov/22982142/

"patients performing HRV-B showed a clear sharp decline in CEA levels, which by three months tended to be significantly lower than in controls"

hindawi.com/journals/jo/20…