Also from USA Today

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Carbohydrates may be the culprit behind painful rheumatoid arthritis
Thu Aug 22, 8:12 AM ET

Anita Manning USA TODAY

Researchers in Massachusetts say they have found a long-sought cause of rheumatoid arthritis, a finding that could point to new areas of research and the development of new drugs to halt the debilitating and painful disease, which affects 2.1 million Americans.

Julia Ying Wang and colleagues at Brigham and Women's Hospital, Boston, and Harvard Medical School ( news - web sites) reported Wednesday that an abnormal immune reaction to carbohydrates in joint cartilage appears to cause the inflammation and swelling of joints characteristic of the disease.

Wang, who presented her findings at a meeting of the American Chemical Society in Boston, says the immune system's ''mishandling'' of carbohydrates called glycosaminoglycans, or GAGs, is an underlying cause of the disease, though why the unusual immune response occurs is not clear.

Previous studies have found elevated levels of GAG in patients with rheumatoid arthritis, Yang says, but until now, research has focused on proteins as a possible cause of the disease, not carbohydrates. ''People think sugars (a carbohydrate) don't do anything,'' she says.

GAGs are a natural part of cartilage and other connective tissues, and are not affected by consumption of carbohydrates.

In arthritic mice and in tissue taken from humans with the disease, Yang found immune-system cells that attach to GAGs in joints. The buildup of these cells causes inflammation and swelling.

High levels of GAG, she says, could be caused by bacteria, which produce enzymes that break down connective tissue, releasing the carbohydrates. And many bacteria and other organisms produce GAG on their cell surfaces, she says, so the immune response to an invading microbe, may mistakenly discern GAG in healthy cartilage as another invader. ''That might explain why so many infections can lead to arthritis,'' she says.

The connection between rheumatoid arthritis and a natural component of cartilage is ''potentially of extreme importance,'' and ''represents an entirely new avenue in which we might begin to explore this disease,'' says John Klippel, medical director of the Arthritis Foundation, who was not involved in the research.

''We don't think of carbohydrates as something that can engage the immune system,'' he says. ''The study would suggest there are cells in the joints interacting with this carbohydrate. One would want to know more about where these cells came from, so you could think about blocking the cells from generating or blocking their interaction with the carbohydrate.''

The finding ''will stimulate an enormous amount of interest'' in further research and could lead to new drugs that would treat the cause of the disease, rather than its symptoms.

http://story.news.yahoo.com/news?tm...satoday/4382294