Silencing gut pain by removing sensory nerves

By surgically removing specific populations of sensory nerves that communicate between internal organs (such as the bladder and gut) and the brain, scientists at Flinders University have found they can silence pain responses without impacting other functions in the body.

The authors say the process, tested in mice, could be used for long-term pain relief, eliminating the need for regular consumption of conventional and highly addictive opiate-derived pain medications that have a large number of side effects. Their findings have been published in the journal Communications Biology.

“Many people experience chronic visceral pain, but there are limited treatment options available as it is notoriously difficult to treat,” said study senior author Professor Nick Spencer.

“Unlike the pain that occurs when we strain a muscle or break a bone, for example, visceral pain is related to our internal organs and occurs in response to many conditions, such as inflammation, irritable bowel syndrome, bladder cystitis, endometriosis or abdominal cancers.

“Generally, the main form of treatment is opiate pain medications including codeine and oxycodone, but these are highly addictive and cause a number of detrimental side effects on the body.”

Understanding how abdominal organs communicate via nerves with the brain is of major interest to medical science; however, identifying which sensory nerve pathways communicate pain sensations from the gut to the brain has been limited by a lack of techniques to determine precisely which populations of sensory neurons detect pain from the gut wall. Flinders researchers have now revealed a new microsurgical technique whereby specific populations of dorsal root ganglia (DRG) can be removed from mice without interfering with other sensory or motor nerves.

“As DRG transmit sensory signals from the peripheral to the central nervous system, using this microsurgical approach we were able to abolish pain responses from certain regions in the large intestine by removing specific populations of DRG,” Spencer said.

“This led to the selective loss of distinct populations of sensory nerve endings within visceral organs, allowing for the long-term silencing of pain signals while not interfering with other functions in the body, even months after the surgical procedure.”

The authors say their technique provides a major pathway for scientific discovery and reveals details about the exact route pain signals are travelling in the body.

“Because of the similarity in sensory processing and pain signalling between different species, our next step will be to demonstrate the success of this approach in larger animals,” Spencer said.

“While this technique has not yet been performed in humans, a similar approach is already used in humans with the intention of blocking pain signals from reaching the brain. This new study is another significant step in our understanding of how the gut and brain communicate and the important role this has across a number of medical conditions.”

Image credit: iStock.com/3283197d_273

Please follow us and share on Twitter and Facebook. You can also subscribe for FREE to our weekly newsletters and bimonthly magazine.