These findings in experiments with pigs may lead to treatments for injuries or osteoarthritis in the knee, according to Duke University Medical Center orthopaedic researchers. The researchers report that two immune system proteins, interleukin-1 (IL-1) and tumour necrosis factor (TNF), block the healing of the damaged pig meniscus, an important layer of buffering tissue within the joint. When agents that counteract the effects of these two proteins were administered directly to the damaged meniscus, the repair process resumed.

The primary function of the meniscus is to act as a shock absorber and a distributor of weight within the joint. Nearly 15 percent of all athletic injuries to the knee involve the meniscus, and the breakdown and loss of this tissue ultimately leads to osteoarthritis.

Duke researchers exposed pig knees to various concentrations of IL-1 and TNF. They found that as they increased the amounts of the proteins, the meniscus tissue was less able to repair itself. The range of concentrations of IL-1 and TNF used in the experiment match those found in the joint fluid of humans with rheumatoid arthritis and osteoarthritis, providing further evidence that these proteins could play a role in the disease process.

“There already is a drug that blocks the effects of TNF that is used widely and effectively in patients with rheumatoid arthritis, the form of the disease caused by body’s own immune system attacking the joint,” Farshid Guilak, Ph.D., senior member of the research team and director of orthopaedic research at Duke said. “Another drug also exists that blocks IL-1 that is being used for rheumatoid arthritis and is currently undergoing clinical trials for osteoarthritis.” These drugs are administered to the entire body. However, the key to the possible new approach would be to deliver these agents directly into the site of meniscus damage, Guilak said.

MEDICA.de; Source: Duke University Medical Center