Posted by ione wong on October 03, 19102 at 15:30:25:
In Reply to: Natural Hormone Causes Arthritis Damage posted by Stephanie on November 27, 1999 at 22:36:07:
: Nov. 27, 1999
: Ed Ungar
: Medical Tribune News Service
: Canadian researchers have identified a substance produced by the body's own immune system that destroys bone and cartilage, resulting in arthritis and osteoporosis. They have also found a way to block its destructive effects.
: When inflammation occurs in the joints, the body's white blood cells swarm to the area to fight the infection. In the process, according to lead researcher Josef Penninger, an immunologist at the Princess Margaret Hospital and Amgen Institute in Toronto (www.uhealthnet.on.ca), the T cells produce a substance called OPGL, which cannibalizes and attacks bone and cartilage tissue.
: Penninger's study, reported in the November 18 issue of Nature (www.nature.com), described a series of experiments in rats. After inducing the initial stages of arthritis in rats, researchers injected the rats with OPG, which blocks the action of OPGL. OPG is a hormone-like substance that is naturally produced in the liver and in certain heart cells.
: Once OPGL was blocked, the effect on the rats was dramatic, according to Penninger. None of the treated rats developed serious joint damage.
: "The rats were running around happily in their cages," said Penninger. "They still had inflammation but there was no crippling whatsoever."
: In contrast, all the rats that did not receive the OPGL blocker went on to develop severe arthritis to the point where they could no longer move about.
: The team also examined tissue removed from human arthritis patients who underwent surgery. In each case, researchers found evidence of OPGL produced by the patients' T cells.
: "This is an exciting and very important study," said Dr. Kathy Siminovitch, director of the University of Toronto program in molecular medicine. "This might not be the only cause, but Penninger has shown a link between the T cells and the bone destruction."
: Researchers at Amgen, which is headquartered in Los Angeles, are testing OPG in humans as well. Penninger suggested that not enough of the blocking agent is getting to the inflamed joints of arthritis patients. In early testing, OPG has been found to be safe. Now, efforts are underway to determine dosage and effectiveness.
: "We have to interrupt the process of inflammation leading to bone and cartilage loss, which, in turn, leads to more inflammation," said Penninger. "My dream is that people who develop arthritis could have a normal life without having to take high doses of medication."
: There are about 100 different types of arthritis involving deterioration of the joints. About 3 million people in North America suffer from arthritis-related diseases, which cost more than $50 billion a year to treat.
: Penninger added that the concept of maintaining a balance between OPGL and OPG applies to all types of arthritis and also to osteoporosis and other diseases involving inflammation and bone loss, including leukemia, skin cancers, hepatitis, AIDS and multiple sclerosis.
: SOURCE: Nature (1999;402:255-262)
: c. 1999 Medical Tribune News Service