Probing the Gut-Brain Mystique
Date: May 1, 2013
For gastroenterologist and neuroscientist Pankaj “Jay” Pasricha, interest in the enteric nervous system—a mesh-like system of neurons governing the function of the gastrointestinal system—goes beyond wonderment.
Neurogastroenterology touches more than abdominal pain, more than gastroparesis or delayed gastric emptying. It’s about the gut-brain axis and how changes there can affect mood, about enteric nerve’s role in obesity and diabetes, about neural stem cells.
So the Johns Hopkins Center for Neurogastroenterology that Pasricha founded—one of few in this country—aims to relieve GI disorders well rooted in the nervous system, like motility and pancreatic pain. But center studies also explore less obvious ties to other diseases, like diabetes, depression and cancer. He also directs the Center for Digestive Diseases at Johns Hopkins Bayview Medical Center.
Pasricha answers our questions about the field, his work and its scope.
How does the enteric nervous system function?
It controls secretion and peristalsis critical for swallowing, digestion, absorption and evacuating the colon. Dysfunction contributes to irritable bowel, gastroparesis and various disabling diseases. But we’re also aware of its hand in the pathogenesis of diarrhea and in inflammatory conditions.
Discuss how your work is shedding light on how visceral nerves affect local tissues.
The enteric nervous system blankets the body with signals regarding metabolic processes—to the brain, liver and, likely, skeletal muscle and fat. Not surprisingly, its influence extends to disease conditions such as insulin resistance and type 2 diabetes—thus our focus on the pancreas. We’ve used 3-D microscopic deep imaging to see how sympathetic nerves pervade islet cells in healthy pancreases. They abut both blood vessels and insulin-producing alpha cells there, which tells something of how they control insulin output. By contrast, in mouse models of diabetes, there’s clear, early remodeling of those nerves—changes that mimic human ones. So we anticipate a new approach to diabetes therapy—one based on changing nerve signaling.
Tell us something we probably don’t know.
Anxiety and depression are thought to contribute to irritable bowel syndrome and dyspepsia. But our studies are showing it may be the other way around. Brain-gut communication likely works both ways.
For the complete interview, visit http://www.hopkinsmedicine.org/.../inside_tract/inside_tract_fall_2012/its_high_time_for_the_gut_brain.