To understand how therapies like vagus nerve stimulation could help control or cure a variety of diseases, it helps to better understand the role the vagus nerve plays in our bodies.

The vagus nerve, a critical component of the parasympathetic nervous system, is like an information superhighway between the brain and various organs. It controls vital functions such as heart rate, digestion and even mood.

“Its primary role is to control internal reflexes deep within our bodies,” said Kevin Tracey, MD, president and CEO of the Feinstein Institutes for Medical Research. “Much like you involuntarily kick your leg whenever your doctor hits your knee with a rubber hammer during an exam, your organs have reflexes, too, that are vital to your well-being.”

He added that the vagus nerve controls another crucial reflex: inflammation.

About a quarter of a century ago, an Italian scientist named Claudio Franceschi coined the term inflamm-aging. He was among the first to describe the phenomenon that as we age, we tend to suffer disproportionately from chronic inflammation, which can lead to any number of serious conditions.

Simply put, over the years we accumulate inflammation cells that linger in various parts of the body where they are no longer needed. Eventually, the very cells that were initially sent to destroy a threat, can become a threat themselves.

“You might think of conditions like depression, heart disease, obesity, Alzheimer’s, arthritis and diabetes as vastly different conditions with very distinct treatments,” said Dr. Tracey. “But they all have one thing in common: inflammation. And the older you get, the more pronounced it is.”

Dr. Tracey and his team discovered the link between the vagus nerve and inflammation in the 1990s. Today, therapies they helped to develop like external stimulation of the vagus nerve, targeted ultrasound techniques and implants that send electrical pulses through the vagus nerve to regulate it, are quickly becoming more mainstream.

Vagus nerve stimulation is currently FDA approved for the treatment of epilepsy, depression and recovery from stroke, and is being tested in everything from Crohn’s disease to Alzheimer’s.

While these therapies have shown remarkable potential worldwide, some challenges remain.

“The vagus nerve system is so large and so complex, that we are just now scratching the surface of what these therapies can potentially mean for millions of patients in the coming years,” said Dr. Tracey.

Part of the problem is that scientists have yet to fully map the vagus nerve, though researchers at the Feinstein Institutes are in the midst of a nearly $7 million project funded by the National Institutes of Health (NIH) to do just that.

Currently, scientists are able to use a technique called optogenetics, which uses laser light beams to activate individual fibers or individual cells in the vagus nerve to learn more about their function and how they communicate with the brain. The vagus nerve is made up of 200,000 individual fibers (100,000 on each side of your neck) that extend to organs and systems like the heart, lungs, spleen, liver, kidneys and digestive tract.

“Once we complete a functional map, however we will then be able to develop methods to selectively target one fiber but not the other,” he said. “This will give the precision necessary to deliver a particular therapy to a particular organ in a particular patient without having side effects.”

The World Health Organization estimates that more than half of all deaths worldwide are associated with chronic inflammation, but the development of vagus nerve therapies to reduce or reverse that inflammation could potentially save millions of lives.

Then there’s the financial toll. By 2030 patients will spend $47 trillion globally on treatments, including medications that carry potentially harmful or even deadly side effects.

Still, the results of these therapies are woefully inadequate. Vagus nerve stimulation could change that.

“It is not a stretch to imagine a scenario where patients could have surgery on their vagus nerve to address any number of conditions, and be done with it,” said Dr. Tracey. “This could be a one-time operation that could spare millions of patients from years or even decades of taking medications and dealing with the side effects.”

“I’ve studied medical history,” said Tracey, “and you can sum up the story of what kills human beings in two words: infection and inflammation.”

During the scientific revolution about 200 years ago, mankind learned that controlling or preventing infection saved lives. Those discoveries have nearly doubled our life expectancy, and advances in better understanding inflammation could have a similar impact.

“It’s not just how long we live, it’s how long we live healthy, productive lives without the burden of chronic illness or the side effects we’re forced to deal with from the pharmacological therapies we currently use to address them,” said Tracey.

He envisions a time in the near future where we could live much more comfortably well past the age of 100. “If solving death from infection added 50 years to human life span then, will solving inflammation add another 50? I think it will add decades to a healthy lifespan. And I think we are much closer to that time than most of us realize.”