July 1998

Blue-Collar Cell Therapy

It's possible now to grow cartilage cells in the lab and reintroduce them into human joints. Skiers and quarterbacks, take heart.

By Stephen S. Hall

Among high-concept forms of medicine, few approaches have as much intuitive appeal as cellular therapy. The idea is disarmingly simple-remove homegrown cells from the patient's body, grow them to vast numbers in the lab and then give them back as medicine. It has already been attempted in a few instances against cancer. Remember the TIL cell-"tumor infiltrating lymphocytes"-craze of the 1980s?

But perhaps the most interesting cellular therapy to date, and the only one to receive the blessings of the Food and Drug Administration as a bona fide biologic intervention, involves not one of the body's vaunted cellular paladins, such as lymphocytes or neurons, but rather a blue-collar cell known as the chondrocyte. These cells provide the cushion known as cartilage between joints, and for the past three years, orthopedic surgeons in this country and Europe have been using them to rebuild knee joints denuded of cartilage by acute or repetitive trauma.

Like many new technologies, this one had a fitful and peripatetic evolution. The initial idea was explored in the early 1980s by a group of surgeons at the Hospital for Joint Disease in New York, including Mark Pitman and a visiting surgical colleague, Lars Peterson. They reported preliminary results in 1984 of cartilage implants in rabbits.

Peterson returned to the University of Goteborg in his native Sweden, where he hooked up-at the suggestion of a tennis partner-with Anders Lindahl, an expert in cell culture. The team ultimately developed a method for culturing cartilage cells and implanting them in humans and received approval to perform the first human implant in 1987, using a technique that is now being taught to more than 2,000 orthopedic surgeons in this country. (The Cambridge, Mass.-based Genzyme Corp. became involved in 1995 when it acquired another company, BioSurface Technology, which was also working on the technology.) The Food and Drug Administration approved the treatment method in August 1997.

At the present time, regulatory approval is limited to procedures that treat the part of the femur (the long bone of the thigh) that meets the knee. When the knee joint is damaged, either in an acute injury such as a skiing accident or by more gradual wear and tear, the cartilage lining the thigh bone where it joins the knee often becomes damaged. This tissue rarely regenerates, and the erosion announces itself with locking, catching, swelling and pain.