A new study shows that molecules involved in our bodies' processing of cannabis, called endocannabinoids, may have the potential to control and prevent intestinal inflammation in mice.
While the research does not necessarily extend to humans, it does hint at why some cannabis users find that the drug helps alleviate symptoms of inflammatory bowel disease (IBD).
The term IBD encompasses a whole range of conditions, like Crohn's disease and ulcerative colitis, where the body's immune system mistakenly attacks the lining of the intestine.
These conditions affect millions of people around the world - some of whom have begun to self-medicate with marijuana, a drug that has known anti-inflammatory properties.
"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," says Beth McCormick, a microbiologist at the University of Massachusetts.
"For the first time, we have an understanding of the molecules involved in the process and how endocannabinoids and cannabinoids control inflammation".
The study has revealed that gut inflammation in mice is regulated by two important processes, which are constantly balancing each other out.
The first process has been identified in previous research and it has to do with the immune system. Often, when a healthy immune system comes across a flourishing colony of bacteria, it responds through inflammation.
That's why a healthy intestine is so remarkable. It's filled with a ton of microbial colonies, but the inflammatory response is latent, just waiting for a foreign pathogen or something unknown to attack.
The second process identified balances the first process out. For the first time, this paper has described a pathway that turns off the immune system's inflammatory response using special molecules called endocannabinoids. These molecules are transferred across the gut lining by the same process that removes toxins from the gut, except the other way around.
When the researchers blocked the endocannabinoid receptors in mice, inflammation was not kept in check and the body's immune cells would attack the intestinal lining.
Endocannabinoids, as you can probably guess, are very similar to the cannabinoid molecules found in cannabis. In fact, the cannabis plant actually led to the discovery of the endocannabinoid system - hence the name.
Because of this connection, the authors think that cannabis could act as a substitute for missing endocannabinoids, by attaching to their receptors, which are found all over the body: in the brain, organs, connective tissues, glands, and immune cells.
"This gives clinical researchers a new drug target to explore to treat patients who suffer from inflammatory bowel diseases, and perhaps other diseases, as well," says McCormick.
If the hunch is proved correct, the trick would be creating a synthetic cannabinoid that only attaches to the correct receptors in the gut, so patients are spared a coinciding head high.
Of course, we can't get ahead of ourselves here. The findings are only based on mouse models so far; even then, the authors are calling for more research to be done on the way endocannabinoids regulate the gut's inflammatory response.
"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 thus far only evaluated this in mice and have not proven this experimentally in humans," says co-author Randy Mrsny, a research pharmacologist.
"We hope, however, that these findings will help us develop new ways to treat bowel diseases in humans."
This study has been published in the Journal of Clinical Investigation.