Scientists have discovered a biological mechanism that could explain claims by some cannabis users that the drug reduces their symptoms of inflammatory bowel disease (IBD).
A study by the University of Bath found cannabinoids help control and prevent intestine inflammation in mice.
This could explain why some marijuana users have reported beneficial effects from cannabis on conditions such as ulcerative colitis and Crohn’s disease.
The researchers hope their findings will help develop new drugs and treatments for gut disorders, which affect millions of people around the world.
Professor Randy Mrsny, from the University of Bath’s Department of Pharmacy and Pharmacology, said: “We need to be clear that while this is a plausible explanation for why marijuana users have reported cannabis relieves symptoms of IBD, we have only worked in mice and have not proven this experimentally in humans.
“However our results may provide a mechanistic explanation for anecdotal data that cannabinoid exposure benefits some colitis patients.
“For the first time we have identified a counterbalance to the inflammation response in the intestine and we hope that these findings will help us develop new ways to treat bowel diseases.”
The researchers from Bath worked with colleagues at the University of Massachusetts Medical School to conduct their study, which is published in the Journal of Clinical Investigation.
They found that gut inflammation is regulated by two processes, which are constantly in flux to respond to changing conditions in intestines.
Previous research identified the first process – a pathway promoting an aggressive immune response in the gut, which is useful to destroy dangerous pathogens but can damage the lining of the intestine when immune cells attack indiscriminately.
The second process, revealed in the new research, turns off this inflammation response via molecules transported across the cells lining the gut into the intestine cavity.
This response requires a naturally-produced molecule called endocannabinoid, which is very similar to cannabinoid molecules found in cannabis, the researchers say.
If the endocannabinoid is not present, inflammation is not kept in balance and can flare up as the body’s immune system cells attack the intestinal lining.
The researchers believe that, because cannabis use introduces cannabinoids into the body, these molecules could help relieve gut inflammation as the naturally produced endocannabinoids would.
Professor Beth McCormick, from the University of Massachusetts Medical School, said: “There’s been a lot of anecdotal evidence about the benefits of medical marijuana, but there hasn’t been a lot of science to back it up.
“For the first time, we have an understanding of the molecules involved in the process and how endocannabinoids and cannabinoids control inflammation.
“This gives clinical researchers a new drug target to explore to treat patients that suffer from inflammatory bowel diseases, and perhaps other diseases, as well.”
The research was funded by the National Institutes of Health in the US.