From The Editor | August 14, 2017

What Happens In Vagus…Is Stimulating!

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By Bob Marshall, Chief Editor

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The vagus nerve is the tenth cranial nerve and interfaces with parasympathetic control of the heart, lungs, and digestive tract. It is the longest nerve of the autonomic nervous system in the human body. The vagus nerve comprises 80 percent to 90 percent of sensory nerves, mostly conveying information about the state of the body's organs to the central nervous system. It is responsible for such varied tasks as heart rate, gastrointestinal peristalsis, sweating, and quite a few muscle movements in the mouth, including speech. The vagus nerve is very important!

When Things Go Wrong In Vagus

So, what happens when the vagus nerve becomes compromised or does not function properly? Many detrimental things can happen, including headaches, bronchoconstriction, epilepsy, gastric motility disorders, depression, or anxiety. Previously, a method of treatment for vagus nerve issues was to implant an electronic pulse generator with electrodes attached to the vagus nerve. However, I recently learned of a new device, developed by electroCore, that delivers the same type of therapy non-invasively. I reached out to Frank Amato, the company’s CEO, to learn more.

Tilting The Odds In Our Favor

electroCore was founded in 2006, and Amato took the helm shortly after his arrival there in 2012. The privately-held company raised over $70 million to support its startup efforts. “Early funding went toward product development and clinical investigation of our gammaCore device,” Amato said.

gammaCore is a hand-held, non-invasive electronic nerve stimulator that works by selectively stimulating particular fibers in the vagus nerve. Treatment is self-administered by the patient positioning the device over the vagus nerve in the neck. Therapeutic treatments typically are 2-3 minutes in length and can be adjusted or repeated.

“We obtained five CE Marks for gammaCore to treat primary headaches, bronchoconstriction, epilepsy, gastric motility disorders, and depression & anxiety within the European Union. We also gained user experience with three to four thousand users in the EU, which helped us to refine user training for better usability,” Amato explained. electroCore was able to identify a biomarker for the proper use of the device, which improved the accuracy of training: When the gammaCore device is properly placed on the neck and activated, the user will feel the corner of is or her mouth pull downward on the same side of the face.

Within the U.S., electroCore received its first 510(k) clearance — for the acute treatment of pain associated with episodic cluster headaches in adult patients — in April, followed by a U.S. launch of the product in July.

The Next Big Show Coming To Vagus

According to Amato, the next focus for electroCore will be gastric motility disorders. “Results of a case series on non-invasive vagus nerve stimulation to treat gastroparesis using the gammaCore device were published and presented at a Bristish Society of Gastroenterology meeting in Manchester back in 2014,” he pointed out.

In that study, seven of the initially-chosen 15 patients diagnosed with gastroparesis complied with the treatment regimen for a sustained period averaging 67 days. Prior to the study, these patients had been experiencing nausea, bloating, and early satiety. These are symptoms of gastroparesis, a disorder in which the stomach does not empty itself of food in a normal fashion. In this initial proof-of-concept study, the compliant patients improved their composite gastroparesis score by 20 percent. This was a good outcome, but further study and more substantial clinical data will be necessary to get a gastric motility disorder indication cleared for the gammaCore device.

Jackpot!

Stanford University currently is recruiting participants for a clinical study on vagal nerve stimulation for gastroparesis using the gammaCore device. The principal investigator for the study is Dr. Linda Nguyen, clinical associate professor and director of GI motility and neurogastroenterology at Stanford. Dr. Nguyen’s Stanford profile page tells you all you need to know about her motivation to work on this study: “Gastroparesis was the defining motility disorder that attracted me to the field of Neurogastroenterology and Motility. My career has been committed to better understanding this disease and other motility disorders in hopes that this will lead to better and more treatment options for our patients.”

The actual start date for the study was March 1, 2017, and it is targeted for completion by July 1, 2018. Target enrollment is 45 participants. Per the stated purpose of the study on ClinicalTrials.gov, “Gastroparesis is thought to be caused by a mix of inflammation and neural dysfunction. The vagal nerve is a large nerve originating from the brain that regulates digestive function. Patients with gastroparesis have what is a called a low vagal tone which results in gastrointestinal motility problems and inflammation; therefore, investigators hypothesize that increasing vagal tone through a hand-held vagal nerve simulator will reduce inflammation and gastrointestinal motility problems in gastroparesis patients. Investigators will evaluate this hypothesis through the use of upper endoscopy testing, breath testing, and blood, stool, urine, heart rate variability, and saliva testing before and after 4 weeks of vagal nerve stimulation (VNS) treatment.”

The study also will include a four-week washout phase post VNS treatment, during which the anticipated positive effects of the treatment should be eliminated.

The potential benefits of this clinical study are immense. First, the ability to treat medical conditions with nerve stimulation, and without the side-effects of pharmaceuticals, would be a huge step forward. Also, though electroceuticals are in development and hold amazing promise, non-invasive treatment of the vagus nerve would minimize the cost of the intervention and eliminate potential complications associated with invasive applications. Finally, given the broad range of bodily functions controlled by the vagus nerve, a breadth of potential treatments could come from effectively learning how to treat ailments like headaches and gastroparesis in this manner. Then, what happens in vagus, will stay in vagus…