July 18, 2002
Calvin Prof/Alum Release Results
A cooperative research project between Calvin College and the Spectrum Health Flow Cytometry Laboratory has confirmed the benefits of a drug used to treat osteoarthritis, a degenerative disease that affects 90% of people over the age of 65.
Calvin biology professor David DeHeer and 2001 Calvin graduate Kyle Sheehan have spent the last three years researching the reasons why a substance called hyaluronic acid helps relieve the pain of osteoarthritis in people who are not helped by such typical anti-inflammatories as ibuprofen. Hyaluronic acid is injected right into the joint, typically the knee joint, in a physician's office and usually given once a week for five weeks. Its benefits, reduced pain and inflamation, last anywhere from six to nine months.
But some physicians and researchers have doubted the worth of hyaluronic acid, which has been used in Europe to treat osteoarthritis since 1987. It's been called "goo," in not all-together flattering terms by some researchers. And DeHeer himself admits: "It's a long, simple, rather unexciting molecule. It's basically repeating sugar units."
But, despite its simplicity, what DeHeer and Sheehan discovered over the last three years is that hyaluronic acid, a natural chemical found in the body in particularly high amounts in joint tissue, is an incredibly effective anti-inflammatory agent in and around the human knee joint (and non-human joints too as evidenced by years of use on race horses).
This summer they are reporting their findings in papers for three different medical journals, including the Journal of Biological Chemistry and the Journal of Orthopaedic Research.
What they'll describe in those papers is their conclusion and how they got to it.
Their conclusion is simple: hyaluronic acid works. But there's more to how it works than meets the eye. The drug is injected into the synovial sac, which protects the joint and also secretes the synovial fluid, which oils the joint. But the half life of the acid is 24 hours, so after about a week the typical injection of two millilitres has disappeared. Yet it continues to work. What DeHeer and Sheehan hoped to figure out was how. What they discovered is that the acid, before it disappears, interacts with a cell called a macrophage. Macrophages produce inflammation.
"Hyaluronic acid," says Sheehan, "basically tells the macrophages to be quiet, calm down, to die. Fewer macrophages means less inflammation." In fact Sheehan and DeHeer found that hyaluronic acid will eliminate about 99% of the macrophage cells. In patients this could contribute to a significant reduction in inflammation and pain.
Their work was done, says DeHeer, at a very basic scientific level. They grew macrophage cell cultures. And they studied the impact of clinical preparations of hyaluronic acid, which they purchased from the two major manufacturers, on those cell cultures, using a sophisticated piece of equipment at Spectrum Health called a flow cytometer. The results, they say, 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."