As anyone with cartilage damage from a sports injury knows, there's not a whole lot doctors can do to help. But scientists from Duke University Medical Center hope to change that within the next three to five years. In a remarkable feat of biochemical alchemy, they have demonstrated a method for turning fat cells into cartilage cells, or chondrocytes. "This holds out the possibility, some time in the future, of taking fat cells from someone with a cartilage injury and growing new cartilage within a mold to replace the damaged tissue," says Geoffrey Erickson, a graduate student at Duke who prepared the results for presentation yesterday at the annual meeting of the Orthopedic Research Society.

The scientists experimented on cells collected from several different liposuctions, treating them with a series of enzymesand a spin in the centrifugeto sort out cells known as adipose-derived stromal cells. These cells were then infused into three-dimensional beads made from a complex carbohydrate called alginate. To these fat-filled beads, the researchers then applied a chemical cocktail of steroids and growth factors. "After two weeks of growth, the treated cells looked and acted like normal chondrocytes when compared to untreated cells," says Farshid Guilak, director of orthopedic research at Duke. The approach will not be available for patients with osteoarthritis-induced cartilage damage, Guilak adds, until scientists understand the cause of that disease