Mapping the Direct Gut-Brain Connection

A team of researchers at Duke University recently announced the discovery of a novel gut-to-nervous-system connection that is likely functions via a more direct route than hormone release.

Published in the latest edition of Journal of Clinical Investigation, the study results highlight possible new mechanisms that provide foodborne viruses with access to the human brain.

Diego Bohórquez, an assistant professor of medicine at Duke University, said, “The study supports the idea that there could be a real biology of gut feelings. As soon as food contacts the wall of the gut, the brain will know in real time what’s going on in the gut.”

According to Bohórquez, “The question was, why would a cell that is supposed to just release hormones have a whole arm? There had to be a target on the other side.” These distinctive arms, called neuropods, are nurtured by support cells named glia that work with neurons.

The researchers tracked the contacts of the neuropods in greater detail, finding that they came close to individual nerve fibers, but not blood vessels, in both the small and large intestine. They found that about 60% of neuropods contacted sensory neurons, bolstering the possibility that they could be central to gut sensation.

Sharing signal similarities with neurons, neuropods had been used by researchers to infect the colons of mice with a disabled version of the rabies virus, which travels through the body initially by infecting neurons.Bohorquez’s team found favorable results: nearly a week after initial virus introduction, only cells with neuropods became infected.

Rodger Liddle, a member of the Duke Institute for Brain Sciences, commented, "That provides a pathway where rabies can go from the lumen of the gut to the nervous system. It implies you might be able to get rabies by eating rabies. Maybe this is a pathway whereby other viruses could infect the nervous system.”

While the study concentrated on connections between neuropods and neurons in close proximity to the intestine, further research is underwaytomonitor the whole path from the gut to brain.