Neurological treatment for inflammation

February 15, 2017
Leigh Erin Connealy, M.D.

Like so many new pathways to health, promising new treatments for rheumatoid arthritis, depression, epilepsy, and more got their start as a surprise. A research team studying the vagus nerve—which links all of our major organs to the brain—found that the nerve had an unexpected ability to prevent inflammation, in unexpected places.

Hello, vagus nerve, pleased to meet you

If you don’t have the vaguest idea about the vagus nerve, I think you’ll be impressed.

It runs from your brainstem down to your abdomen, passing through the heart, esophagus, stomach, and lungs along the way. As part of our involuntary nervous system, it controls what our bodies do unconsciously—regulating our heart rate, managing the digestive processes, and keeping us breathing, for example.

Our new understanding of how it works is the result of an inspiring story about surprises in the research…followed by educated guesses, ingenious experiments, stubborn persistence, and finally, success.

And talk about dedication—we’re talking about more than 10 years of hard work. A shout out to all you determined researchers out there. We owe you.

In the beginning…

Looking for ways to reduce stroke-related inflammation in the brain, the research team injected a small amount of an anti-inflammatory drug into a lab animal’s inflamed brain.

They noticed that the drug didn’t just block inflammation in the animal’s brain—it also blocked inflammation in its spleen.

This was totally unexpected. The amount of the drug in the brain was far too small to have entered the bloodstream and traveled to other parts of the body. Clearly, there was another channel of communication between the brain and the spleen.

Hmmm… Why? How?

Good science needs good hypotheses.

Maybe the brain was using a particular part of the nervous system—the vagus nerve—to instruct the spleen to switch off inflammation. That is, perhaps the brain was directly regulating inflammation in body tissues.

Well…except for one thing.

That hypothesis slammed headlong into what we thought we knew: Communication between the immune system cells in our bloodstream and organs, using the electrical connections of the nervous system, was considered impossible. Indeed, the brain has an independent, autonomous nervous system of its own, protected from unwanted outside influence by the blood-brain barrier.

Even so, here, it looked like the two systems were intimately, intricately linked.

Time to test the hypothesis by cutting the vagus nerve, injecting the same anti-inflammatory drug into the same part of an identical lab animal’s brain.

The result?

With the vagus nerve disconnected, the anti-inflammatory drug had no effect elsewhere in the body.

OK, so now we test whether we can stimulate a healthy vagus nerve to send out anti-inflammatory instructions—but using electrical signals that we generate, instead of the anti-inflammatory drug.

Result? Same as with the drug. Healthy vagus nerve plus electrical stimulation blocked inflammation in the spleen.

Breakthrough! The vagus nerve helps the brain communicate with more of our body than anyone knew.

Through the newly-opened door

The research team spent the next ten years mapping every neural pathway along the length of the vagus nerve.

They finally nailed how the vagus nerve controls inflammation. It sends a message to the spleen to cease production of an inflammation-fueling protein called, tumor necrosis factor (TNF).

So it was time for the real test.

A test of nerve

In 2011, volunteers suffering severe rheumatoid arthritis, and taking conventional medications to suppress its symptoms, were implanted with a small pacemaker-like device with wires attaching to the vagus nerve in their throat.

They were instructed to swipe a magnet across their throat six times a day. This would, they hoped, activate the implant to stimulate the vagus nerve for 30 seconds at a time, which would in turn reduce the inflammatory response caused by their arthritis.

The hope was for a modest reduction in pain.

The results far exceeded that.

A few weeks after the test, a 68-year old grandmother of eight, who was often virtually immobilized by her arthritis, was back playing senior volleyball, bicycling for an hour a day, and doing gymnastics. She will need to continue a low dose of her prescription drug indefinitely, but finds that no obstacle.

Others had similarly life-changing experiences:

  • Of the 20 patients in the trial, 16 not only reported they felt better, but also had reduced measures of inflammation in their blood
  • More than half showed significant improvement, and around one-third are in full remission—fully cured, in effect, of their rheumatoid arthritis, for which there had never been a cure
  • Even those few who experienced no clinically significant improvements with the implant insisted it helped them. Nobody wanted theirs removed.

How happy an ending is this?

Follow-up studies by the research team underscored the effectiveness of vagus nerve stimulation:

  • When stimulation was temporarily discontinued, the arthritic pain returned, and TNF levels in the blood increased
  • When stimulation was restarted, symptoms again disappeared

I call that a very well done deal. A happy ending that marks an equally happy beginning, as brilliant researchers continue to work out how vagal stimulation can improve the health and lives of millions of people.

What’s ahead?

This happy ending gets even happier. On the heels of vagal stimulation successes with rheumatoid arthritis, came advances in the treatment of epilepsy and severe depression. And an implantable device is under study for the treatment of heart failure.

And new, noninvasive vagus nerve stimulation devices, requiring no implantation, have been approved in Europe to treat epilepsy, depression, and pain, but have not yet been approved in the U.S.

Others are currently studying vagus nerve stimulation as a potential treatment for multiple sclerosis, headache, pain, and Alzheimer’s disease. And there are even some health care practitioners using manual vagus nerve stimulation.

That research team and all those who have followed have truly struck a nerve.

If you’re epileptic or severely depressed, vagus nerve stimulation might be a life-changing help. Make sure your doctor knows about it.

Take good care.

References

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  • Patricia Lowney

    I hope this investigation continues,it sounds very promising!

  • Sheepdog135

    Excellent article! I have RA and occasional Gout episodes (usually very severe) so this is excellent news, especially since it is now being done as a noninvasive procedure. Guess it’s up to the pols and the FDA to open the door here in the USA.

  • movingwaters

    Thanks for this really informative article. This is good news!

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