Defusing arthritis with oral collagen.

Defusing arthritis with oral collagen

Oral doses of collagen -- a structural protein especially important in joints--may hold promise as a treatment for rheumatoid arthritis, according to new animal research. Indeed, the study's authors propose that ingestion of different bodily "building blocks" might combat other autoimmune diseases. Physicians might someday limit oreven shut down the self-destructive cycle of auto-immunity, they suggest, by feeding patients small quantities of the substance under attack.

Howard L. Weincer, an immunologist at Brigham and Women's Hospital in Boston, says he opted for the oral route in his collagen tests with rats because people "generally don't become sensitized to proteins that go through the gut." In clinical practice, he adds, oral doses offer a simpler apprach than intravenous collagen injections, which have yielded mixed results in previous trials.

To create an autoimmune disease that mimics human rheumatoid arthritis, Weiner and his colleagues injected Mycobacterium tuberculosis into the tails of approximately 200 rats. Although rats with this disease develop an autoimmune attack against collagen II, scientists have generally assumed that collagen reactions do not play a central role in the animals' arthritis, Weiner notes. But in the Oct. 15 JOURNAL OF IMMUNOLOGY, his team reports data indicating that an experimental treatment limiting the body's attack against collagen II also dramatically diminished symptoms of arthritis.

The researchers fed 3 to 3,000 micrograms ([mu]) of collagen II to groups of 20 or 40 rats three times in the week preceding the bacterial injection. Thirteen days after the injection, animals receiving no collagen pretreatment developed the classic swelling and redness of arthritic joints. The same symptoms took up to two days longer to develop, and were only 56 to 68 percent as severe, in animals pretreated with 3 or 30 [mu] of collagen (the most effective doses). Moreover, these rats showed little allergic response to collagen in standard skin tests. The study also suggests that white cells called suppressor T-cells are involved in the arthritis suppression.

Similar results with animals fed myelin -- a nerve-sheath material under autoimmune attack in multiple sclerosis -- have led Weiner to begin oral myelin trials in multiple sclerosis patients. Next year, working with David E. Trentham at Boston's Beth Israel Hospital, he plans to conduct a six-month trial of oral collagen in 10 patients with rheumatoid arthritis.