Dear Pain Matters blog readers,
One of the most under-appreciated nerves of our body is the vagus nerve. In Latin, the word ‘vagus nerve’ literally means ‘wandering nerve’. (In fact, the words vagrant, vagabond, and vague are all based on the same word, ‘vagus’.)
So what does this vagus nerve do?
Answer: Too much to answer in a single blog post, that’s for sure!
As such, I will only focus on one function of the vagus nerve (from an ‘inflammation/pain’ perspective).
Persistent localised inflammation is a key component of, and contributes to pain in, many chronic pain conditions including CRPS, rheumatoid arthritis (joint inflammation), and inflammatory bowel disease (Crohn’s disease, ulcerative colitis).
Dr Kevin Tracey’s research –
Dr Kevin Tracey’s team found that stimulation of the efferent vagus nerve (motor branch of the vagus nerve) can significantly curtail, and even block, the release of potentially damaging pro-inflammatory cytokines. Not only can activation of the efferent vagus nerve protect against organ and tissue damage, but it may also reduce pain caused by inflammation.
Specifically, stimulation of the ‘Cholinergic Anti-Inflammatory Pathway’ including the efferent vagus nerve leads to decreased release of pro-inflammatory mediators including tumor necrosis factor alpha (TNF), hence reduced localised inflammation.
So what?? (you may ask)
In November 2012, Dr Kevin Tracey’s lab reported the first successful clinical trial that showed that stimulation of the vagus nerve can be effective for decreasing inflammation and pain in Rheumatoid Arthritis patients.
This is very exciting news….and it raises further questions….
For example, if stimulation of the vagus nerve can be effective in Rheumatoid Arthritis patients, could stimulation of this same vagus nerve also offer certain relief from inflammatory pain to other chronic pain patients with persistent localised inflammation (including some patients with CRPS, inflammatory bowel disease, etc)?
If yes, could vagus nerve stimulation be offered in addition to, or as an alternative to, current pain treatments?
I look forward to further updates of Kevin Tracey’s clinical study involving stimulation of the vagus nerve in Rheumatoid Arthritis patients.
Any benefits to Rheumatoid Arthritis patients may offer hope and inspiration to some chronic pain patients with persistent inflammation (eg CRPS, inflammatory bowel disease, etc).
Here’s to ‘less chronic pain, more gain’.
Dr Kevin Tracey
(2) “SetPoint Medical Presents Positive Clinical Results for First Human Study of Implantable Neuromodulation Device for Rheumatoid Arthritis” (12 Nov, 2012).
(3A) The Body Electric
(3B) …Or click here for interview with Dr Kevin Tracey (if above link does not work):
Dr. Kevin Tracey Explains How A Nerve Stimulator Could Change Arthritis Treatment
(4) Can the Nervous System Be Hacked?
By Michael Behar; 23 May, 2014; The New York Times (Magazine)
(5) Fox, Douglas. The Shock Tactics Set to Shake Up Immunology. Nature (04 May 2017); 545: 20–22.
Academic papers by Kevin J Tracey (there are now over 315 published papers):
(6) Koopman FA, Chavan SS, Miljko S, Grazio S, Sokolovic S, Schuurman PR, Mehta AD, Levine YA, Faltys M, Zitnik R, Tracey KJ, Tak PP. Vagus Nerve Stimulation Inhibits Cytokine Production And Attenuates Disease Severity In Rheumatoid Arthritis. PNAS (2016); 113(29): 8284-8289.
(8) Bonaz B, Sinniger V, Hoffmann D, Clarençon D, Mathieu N, Dantzer C, Vercueil L, Picq C, Trocmé C, Faure P, Cracowski J-L, Pellissier S. (2016), Chronic Vagus Nerve Stimulation in Crohn’s Disease: A 6-Month Follow-Up Pilot Study. Neurogastroenterol Motil (2016); 28: 948–953.
(9) Sabina Walker, Peter D. Drummond; Implications of a Local Overproduction of Tumor Necrosis Factor-α in Complex Regional Pain Syndrome [Review Paper, 24 pages]; Pain Medicine (Dec 2011), 12 (12), 1784–1807.
(Our 24-page Review Paper includes extensive discussion of Kevin Tracey’s research and whether this research may be relevant to CRPS.)