Stanford Medicine researchers have developed a treatment that reverses age-related cartilage loss and prevents arthritis after knee injuries in mice. By blocking the enzyme 15-PGDH, a so-called 'gerozyme' that increases with age, the therapy restored healthy, shock-absorbing cartilage and improved joint function. Human cartilage samples from knee surgeries also regenerated when exposed to the treatment.

The approach targets the root cause of osteoarthritis, a degenerative disease affecting millions with no approved drugs to reverse cartilage damage. Current treatments only manage pain or require joint replacement surgery. The Stanford team discovered that 15-PGDH levels double in aging cartilage, and inhibiting it triggers chondrocytes to enter a more youthful state without relying on stem cells—a novel regeneration pathway.

Published in *Science*, the research suggests future therapies could be delivered via oral pills or targeted injections, potentially reducing the need for joint surgery. An oral version of the gerozyme inhibitor is already in clinical trials for age-related muscle weakness. The findings offer a direct attack on the disease mechanism, not just its symptoms, marking a potential shift in osteoarthritis treatment.