Goo Is Getting The Green Light

September 16, 2002
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GRAND RAPIDS — A three-year research project by a Calvin biology professor and one of his students has established that a naturally occurring substance called hyaluronic acid is a real help in treating arthritic joints.

Now the professor, David DeHeer, is setting forth on a more lengthy study to find whether the substance — known in the trade as “goo” — also helps people who’ve undergone joint replacement and, further, exactly the way in which it functions to begin with.

DeHeer started his career as a researcher with the Scripps Clinic and Foundation in the San Diego area and later became part of the Grand Rapids Orthopedic Surgical Residency Program.

Though he’s no longer affiliated with the program, he conducts independent research half-time and lectures half-time at Calvin.

The project — which he conducted with Kyle Sheehan, a 2001 Calvin graduate — determined that goo works by interacting with a cell called a macrophage (pronounced “MAK-ra-faszh”). The pair undertook the project with the cooperation of Spectrum Health Flow Cytometry Laboratory.

DeHeer explained that macrophage cells inflame joints, and the pair’s research showed that goo eliminates about 99 percent of the macrophage cells in a joint. In patients this could contribute to a significant reduction in inflammation and pain.

They reported their findings in papers for three medical journals, including the Journal of Biological Chemistry and the Journal of Orthopaedic Research.

What DeHeer wants to do now, he told the Business Journal, is determine what causes the cells that naturally produce goo to quit their job. He also hopes to determine goo persists in the vicinity of replaced joints, and exactly what cellular mechanism is at work between goo and microphages.

He said that if hyaluronic acid is a help for people who’ve undergone joint replacement, then the problem becomes how to deliver the medication to their joints.

Normally, he explained, a doctor can inject goo during an office visit. The material is injected directly into a joint’s synovial sac. The sac protects the joint and also secretes synovial fluid, which oils the joint. Such injections usually are given once a week for five weeks, a process that reduces pain and inflammation for six to nine months.

But DeHeer explained that no doctor dares make injections into a replaced knee or hip joint because of fear of infection. Yet the muscle, ligaments and nerve tissue surrounding such joints are susceptible to inflammation thanks to contact with the joints’ alloys.

“It’s kind of like the artificial joint is in a baggy,” DeHeer said. “The doctors really don’t want to penetrate it.”

But he believes that if it’s possible to find out exactly what’s going on between goo and microphages, then drug developers can develop a medication that will deliver goo to the joints without injection.

Deheer said he believes the research will settle the doubts of some physicians and researchers about the value of hyaluronic acid, used in Europe to treat osteoarthritis since 1987. DeHeer terms the substance a “long, simple, rather unexciting molecule. It's basically repeating sugar units.”

Their work was done, says DeHeer, at a very basic scientific level.  They grew macrophage cell cultures and studied the impact of clinical preparations of hyaluronic acid on those cell cultures, using a sophisticated piece of equipment at Spectrum Health called a flow cytometer.  The results, he said, were dramatic: Macrophage cell cultures treated with the acid were decimated; those not treated thrived.

“The result,” says DeHeer, “is that macrophage cells behave like they do in a person without osteoarthritis.

“There are lots of big molecules of hyaluronic acid, but hardly any macrophage cells —thus, a reduction in inflammation and a reduction in pain. This unexciting molecule has a very exciting role in the knee joint.”

Now, he said, the next step is to find the mechanism. He believes the project could take five years.

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