MONDAY, April 29, 2002 (HealthDayNews) -- A small chunk of synthetic genetic material may hold promise as a treatment for serious bowel inflammation.
Researchers in the United States and Israel have found that mice inoculated with fragments of manmade bacterial DNA gain temporary protection from inflammatory bowel disease, a debilitating form of intestinal distress.
Germ DNA has previously been shown to promote protection from allergies. But the latest work, reported in the May issue of the journal Gastroenterology, is the first to suggest it might help with gastric irritation, too.
Inflammatory bowel disease is an umbrella term for ulcerative colitis and a related condition, Crohn's disease, which together affect roughly 1 million Americans. A much larger number of people, perhaps 30 million in this country alone, suffer from irritable bowel syndrome (IBS) -- a generally milder intestinal ailment. Unlike colitis, IBS is not marked by inflammation. However, it can still make life miserable for people by causing painful diarrhea, bloating, constipation and other unpleasant symptoms.
The synthetic DNA is called an immunostimulatory oligonucleotide (ISS-ODN). Scientists have found it generates a "danger-like signal" to the immune system, warning of a potential microbial invasion. In response, cells and chemicals that fight infection spring to action.
ISS-ODN also appears to shield cells in the intestinal lining in another way, deterring them from committing suicide.
In the new work, a team led by Dr. Eyal Raz of the University of California, San Diego, gave both injections and oral forms of ISS-ODN to groups of mice with bowel ailments that mimiced various types of colitis. The synthetic DNA reduced inflammation and prevented gut cell death, Raz's group found. However, when the treatment was stopped the symptoms returned, suggesting the therapy doesn't offer long-term protection unless given continuously.
Raz said there's no obvious reason the approach wouldn't work in people with inflamed bowels, and his Israeli colleagues are now preparing a human trial with the therapy. Preliminary evidence from tissue samples of colitis patients has found the DNA fragments do seem to soothe intestine cells.
Current treatments include steroids and antibody therapy, which can be expensive and cause potentially severe side effects. As for ISS-ODN, "there isn't too much in terms of side effects that would make you think twice about using it. It's relatively very safe," Raz said.
In other developments affecting the treatment of IBS, a U.S. Food and Drug Administration (FDA) panel last week took the highly unusual step of recommending the agency lift its ban on a previously approved drug for women with IBS. The drug, Lotronex, was pulled in November 2000 after being linked to serious intestinal side effects and several deaths.
Nancy Norton, president of the International Foundation for Functional Gastrointestinal Disorders, testified at the FDA panel hearing in support of bringing back Lotronex.
"We are concerned that patients have access to a medication that clearly provides benefit to them," Norton said. The drug "was truly life-altering. It gave them their life back, and then it was taken away from them."
Should the FDA follow its panel's advice -- it typically does -- Norton said the agency and GlaxoSmithKline, which makes the drug, would need to have an adequate safety plan to protect people who use Lotronex.
The prospect of Lotronex's return dismayed consumer protection advocates who had lobbied the FDA to take the drug off the market.
Dr. Sidney Wolfe, director of Public Citizen's Health Research Group, told the panelists "the reintroduction of Lotronex into the market, even with the restrictions proposed by Glaxo, would be a serious public health mistake, likely, if not certain, to result in the need to ban the drug again."
What To Do: To learn more about inflammatory bowel disease, visit the Crohn's & Colitis Foundation of America. For more on irritable bowel syndrome, try the National Institutes of Health.
