New Irritable Bowel Disease Treatments Aim for the Gut

Aug. 24, 2000 -- The thousands of Americans who suffer from irritable bowel disease (IBD) could one day get relief in the form of a harmless bacteria that can deliver medicine right to the intestines, where it's needed.

Up to a million people in the U.S. have IBD, in the form of Crohn's disease or ulcerative colitis, according to the Crohn's and Colitis Foundation of America. People with Crohn's disease, a chronic condition involving inflammation of the intestines, have frequent diarrhea, abdominal pain, and sometimes fever and rectal bleeding. Ulcerative colitis is a similar condition with similar symptoms, but it affects only the colon or rectum. Although the exact cause of IBD is unknown, research suggests that the body's own immune system contributes to the disease process.

Despite recent advances in treatment, the drugs used to combat IBD are far from perfect. Recent studies have suggested that a drug that regulates the responses of the immune system may help quiet the inflammation of IBD. But the drug, known as interleukin-10 or IL-10, can suppress the immune system. So it must be given in small doses, by injection or enema, frequently enough that it can be useful in the intestines.

Researchers who describe their work in the journal Science believe they've found a better way to deliver the drug to the intestines so that it can function as effectively as possible. The researchers, led by Lothar Steidler of Gent University in Belgium, gave a bacteria that that had been genetically engineered to secrete the drug to one group of animals with colitis and another group of animals that had been engineered to develop colitis The harmless, edible bacteria that carried the drug into the intestines is normally used to produce and preserve fermented food.

The animals with colitis who were given bacteria for 14 days had a 50% decrease in symptoms, which Steidler and colleagues say is better than improvements seen with similar drugs. In the animals expected to develop colitis, the treatment stopped symptoms from developing.

"It's definitely interesting," says Claudio Fiocchi, MD. "The fact that you can take it by mouth every day and it goes [to the intestines] and controls inflammation, that is great."

But Fiocchi, a professor of medicine at Case Western Reserve University in Cleveland, cautions that the experiment must be duplicated in humans. He says researchers must demonstrate both that this method is effective and that it causes no unwanted side effects. "It's potentially another option," he tells WebMD.

In an editorial accompanying the study, Fergus Shanahan, MD, of Cork University Hospital in Ireland, points out that while the idea of using harmless bacteria to deliver highly concentrated doses of drugs to far-flung areas of the body is promising, many questions must be answered before this treatment method can be offered to patients.

"Chief among these is a safety concern if bacteria of human intestinal origin are engineered to secrete biologically active agents such as IL-10," writes Shanahan. "What might be the outcome of person-to-person transmission of such organisms?"

Also, he says researchers must determine which patients are most likely to benefit from the new treatment method, and how it will fit in with other medications patients must take.