Inflammatory Bowel Disease May Respond To Cannabis-Derived Drugs

MedPage TODAY
Sep. 14, 2005

BATH, England, Aug. 16-British researchers have found a cellular rationale for the use of cannabis-derived drugs, possibly even smoked marijuana, as an adjunct in treating inflammatory bowel disease.

Investigating anecdotal reports that cannabis in the form of smoked marijuana relieves some of the symptoms of inflammatory bowel disease, the researchers here tried to find out why that might be so.

They performed histological examinations, signaling experiments, and wound healing experiments on healthy colon tissue samples and samples from patients with inflammatory bowel disease.

Two potential targets for cannabis-derived drugs, the G-protein-coupled cannabinoid receptors, CB1 and CB2, are expressed in the human colon, Karen Wright, Ph.D., of the University of Bath here and colleagues reported in the August 2005 issue of the journal Gastroenterology.

Furthermore, these receptors were activated by a variety of natural and synthetic cannabis-derived compounds and may play a role both in wound healing and in the body's response to inflammatory bowel disease, said the Bath team.

The study did not address the issue of smoked marijuana directly, and an accompanying press release said smoking marijuana for inflammatory bowel disease would be inappropriate.

In healthy tissue samples, the CB1 receptor was present in colonic epithelial and smooth muscle cells, while the CB2 receptor was identified in immune system cells including macrophages and plasma cells.

In diseased tissue samples, the presence of CB2 increased significantly, and the receptor appeared in epithelial cells, most notably in cells bordering sites of ulceration.

This evidence suggests that the CB2 receptor, which is known to play a role in suppressing the immune system, may be part of the body's attempt to bring inflammatory bowel disease under control and restore a healthy state in the gut, the researchers speculated.

Signaling experiments showed that both receptors bound to and were activated by cannabinoids such as anandamide and noladin ether, indicating that the receptors were turned on in the human colon.

Finally, wound-healing experiments performed on cultured cells indicated that CB1 agonists could promote wound closure, while CB2 agonists did not, suggesting that the CB1 receptor may play a role in healing ulcers caused by inflammatory bowel disease.

Overall, the study provides further evidence that cannabinoids "may have a direct influence on the human large intestine" and may play a role in gastrointestinal physiology and pathophysiology. The CB1 and CB2 receptors may prove to be useful targets for cannabis-derived drugs for treating inflammatory bowel disease, the researchers concluded.

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