Crohn’s and Bacteria

A study at a research facility in Montreal has nearly doubled the number of genetic regions known to be involved in inflammatory bowel diseases, including Crohn’s disease. Many of these regions—163 are now known—are also associated with autoimmune disease. Genetic regions are areas of DNA normally associated with specific organs or functions; most of the ones known for IBD are part of the system for fighting microbial infections.

This finding suggests that Crohn’s disease and ulcerative colitis, another inflammatory bowel disease, are related. It also lends support to the notion that Crohn’s is the result of an excessive immune response to bacteria. In fact, another study, in Australia, has found specific bacteria that are believed to trigger the condition. Called Proteobacteria, they are a normal component of what doctors all intestinal flora but were found in elevated levels in people with Crohn’s. The researchers had found earlier that specific strains of a Proteobacteria species called Campylobacter concisus had infected the intestinal cells of Crohn’s patients.

In Crohn’s disease, the small intestine or colon becomes inflamed, which is believed to be an immune reaction to harmless intestinal flora. This causes painful abdominal cramping, as well as other symptoms, such as bloody diarrhea. Crohn’s is often accompanied by poor appetite and weight loss. In addition to the discomfort, the disease can cause ulceration and other damage to the intestines which in many cases needs to be repaired with surgery.

Fortunately, while bacteria are involved in causing the disease, French researchers may have found a way to use bacteria to treat it. Crohn’s patients tend to be deficient in a protein called elafin. The researchers created genetically altered lactic acid bacteria, the sort that maker milk into cheese, which is safe for human consumption. The genetic modification made it so that the bacteria would create the elafin protein. When given to mice with IBD symptoms, the lactobacilli reduced inflammation. The treatment hasn’t been tested in humans, but the bacteria did reduce inflammation in biopsied tissue from Crohn’s patients, a sign that it may be effective for people.

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