photoWhen osteoarthritis strikes your knee, or other joint, about the only option currently available is joint replacement surgery, a costly and painful procedure.

Now, researchers at Brigham and Women's Hospital (BWH) report an injectable gel could spell the future for treating this disease and others.

Among its advantages, the gel could allow the targeted release of medicine at an affected joint, and could dispense that medicine on demand in response to enzymes associated with arthritic flare-ups.

"We think that this platform could be useful for multiple medical applications including the localized treatment of cancer, ocular disease, and cardiovascular disease," said Jeffrey Karp, leader of the research and co-director of the Center for Regenerative Therapeutics at BWH.

Aging population

Joint replacement surgeries are becoming more common, and are expected to increase in the years ahead as Baby Boomers age.

Arthritis is a good example of a disease that attacks specific parts of the body. Besides surgery, conventional treatments for largely involve drugs taken orally.

Not only do these take a while to exert their effects, they can have additional side effects. That is because the drug is dispersed throughout the body, not just at the affected joint. Further, high concentrations of the drug are necessary to deliver enough to the affected joint, which runs the risk of toxicity.

Targeted delivery

"There are many instances where we would like to deliver drugs to a specific location, but it's very challenging to do so without encountering major barriers," said Karp, who also holds appointments through Harvard Medical School (HMS), Harvard Stem Cell Institute (HSCI), and the Harvard-MIT Division of Health Sciences and Technology (HST).

If such a gel were practical, what would it be made of? To cut the time involved in bringing a new technology to market, the research team focused only on materials already designated by the Food and Drug Administration (FDA) as being generally recognized as safe (GRAS) for use in humans.

After a series of tests with the gel, the team is convinced it works. Among other promising results, the researchers found that gel injected into the healthy joints of mice remained stable for at least two months. Further, the gel withstood wear and tear representative of conditions in a moving joint.

Additional tests in mice are underway. The technique has yet to be demonstrated in humans, but the researchers write that it "should have broad implications for the localized treatment of many...diseases" caused by the enzymatic destruction of tissues. For an aging population with stiff, aching joints, it just might provide an alternative to joint replacement.