Cannabis and inflammatory bowel disease

Research indicates the potential to use cannabis as an alternative treatment for IBD.

Inflammatory bowel disease (IBD) is an autoimmune disease that affects the lining of the gastrointestinal (GI) tract and disrupts the body's ability to digest food, absorb nutrition, and eliminate waste. Inflammation is caused by the body’s response to mistaking natural gut bacteria for harmful, foreign material, thereby causing an increase in gastric acid secretion and permeability.

Crohn's disease and ulcerative colitis (UC) are two types of IBD that are differentiated by the location and extent of inflammation. Diagnostics of Crohn’s disease are 1) inflammation occurs anywhere in the GI tract with a tendency to localize in the lower part of the small intestine and colon; 2) inflammation is often patchy leaving diseased portions along healthy sections of the GI tract; and 3) inflammation penetrates the inner and outer lining of the intestinal wall. On the other hand, UC is more simply characterized by localized inflammation of the inner layer of large intestinal wall. Symptoms of IBD are universal and include abdominal pain and cramping, gas and bloating, diarrhoea or constipation, fatigue, and weight loss.

Drug therapy and surgery are the current treatment options for IBD. These drugs include anti-inflammatories, immune system suppressors, and antibiotics, most of which have a range of side effects e.g. excessive facial hair, high fever, insomnia, hyperactivity, diabetes, glaucoma, and kidney and liver damage. Surgery to remove the entire colon and rectum (proctocolectomy) occurs in 25-45% of UC sufferers, and in most cases an ileoanal anastomosis eliminates the need for a colostomy pouch. Up to half of people with Crohn’s disease require at least one surgery in their lifetime to remove damaged areas and sew healthy sections together.

People with IBD might use cannabis to reduce inflammation, manage pain, diarrhea, or to treat any of the side effects associated with their current drug therapy, including recovery from surgery. As the empirical body of evidence grows, the role of the endocannabinoid system (ECS) in the maintenance of physiological functions including digestion and immune response is becoming better understood. The ECS is a group of endogenous receptors (i.e. CB1, CB2) located in the brain, organs, connective tissues, glands, and neuromodulatory lipids (binding molecules) and their associated receptors. Tetrahydrocannabinol (THC) and cannabidiol (CBD) are chemically analogous to endogenous lipids and are therefore expected to play an important role in the regulation and integrity of the ECS. The interaction of the ECS with key physiological processes helps regulate internal and cellular homeostasis.

In terms of the digestion system, CB1 receptors are found in the stomach and colon, while CB2 receptors are found in immune cells and throughout the enteric nervous system. More specifically, research suggests that the activation of CB1 receptors found in the GI tract inhibits gastric acid secretion, reduces GI permeability, and mediates the body’s analgesic effects on visceral pain. Autoimmune diseases are complex and not well understood and the presence of CB2 receptors within our immune system isn’t enough to draw inferences about a more specific role of cannabis in the treatment of autoimmune dysfunction. Consider the variability between type 1 diabetes, rheumatoid arthritis, and inflammatory bowel disease, as well as differences and compounding effects among individuals. Generally speaking, cannabinoids have the potential to modulate immune system function through the ECS as well as to promote wound healing.

References

Di Carlo, G. and A.A. Izzo. 2003. Cannabinoids for Gastrointestinal Disease: Potential therapeutic Applications. Expert Opinion on Investigational Drugs 12(1):39-49.

Duncan, M. and A.A. Izzo. 2014. Phytocannabinoids and the Gastrointestinal System in Pertwee, R.G. (editor) Handbook on Cannabis. Oxford (UK), Oxford University Press. Pgs 227-244.

Nasser, Y., M. Bashashati, and C.N. Andrews. 2104. Towards modulation of the endocannabinoid system for gastrointestinal disease: FAAHster but not “higher”. Neurogastroenterol Motility 26: 447-454.

Schicho, R. and M. Storr. 2014. IBD patients find relief in cannabis field. Nature Reviews Gastroenterology and Hepatology. 11(3): 142-143.

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