Knee Repair with Stem Cells Could Help Millions

By Lauran Neergaard, The Houston Chronicle, August 21, 2006

Injections of bone-marrow stem cells and implanted "cartilage plugs" top the list of wanted treatments, as doctors test innovative processes to stimulate cartilage regrowth in damaged knees.

The cartilage that cushions the knees has only a limited natural ability to repair itself, thus, the knees are are the joints most likely to become problematic. The need for new and innovative treatments is great.

Unlocking the ability for accelerated self repair of the joint is the primary goal.

Those individuals who only require small amounts of cartilage to grow are the preliminary group to try the new alternatives.

The techniques, if they do indeed work, could help people with arthritis as well since their cartilage breaks down over time.

The pad of cartilage referred to as the meniscus, basically the knee’s shock absorber, is the first to be in clinical trials for this treatment. Using cells from donated bone marrow with an aim to regenerate tissue, the outcome is eagerly anticipated.

The meniscus is surgically removed in about 800,000 American's each year. A painful tear can result in an older person with only a simple wrong step, due to the fact that the pad deteriorates with age. Thus, young athletes are not the only ones who can suffer. Meniscus injuries are commonplace in this world.

Studies have demonstrated that combining knee lubricating fluid with stem cells helps to regrow the meniscus in goats. The adult stem cells are called Mesenchymal cells, and live within bone marrow. These cells can convert into cartilage forming cells called chondrocytes. Is it possible that the cells which serve as building blocks for tissue could also work similarly in humans?

Individuals with half of their meniscus removed enrolled in the study, 55 patients total. The study consisted of a placebo injection or one containing millions of mesenchymal stem cells; these were administered one week after the meniscus surgery.

Researchers are now evaluating each patients remaining meniscus for signs of regrowth using high powered MRI machines.

"No one's ever looked at the meniscus in terms of volume," says Dr. Thomas of the University of Southern California, lead researcher for the study.

Preliminary results are due in October and so far there have been no safety problems. The study is still blind so researchers are oblivious to which patients were among the placebo group and which were not.

"It's very, very exciting research," says Dr. David, an orthopedic surgeon and sports medicine specialist at Washington Hospital Center in the nation's capital.