Researchers at Stanford University have identified a single protein responsible for the breakdown of joint cartilage with age, raising hopes of a future treatment that could make joint replacement surgery unnecessary.
The protein, known as 15-PGDH, becomes more active as the body ages and interferes with molecules that repair tissue and reduce inflammation. When scientists introduced a drug blocking this protein in older mice, worn knee cartilage began to thicken. In younger injured mice, the treatment prevented osteoarthritis from developing at all.
Unexpectedly, the recovery did not require stem cells. Instead, existing cartilage cells called chondrocytes were simply reprogrammed into a healthier state. Treated mice showed steadier movement and placed more weight on injured limbs, indicating reduced pain.
The results also held in human tissue. Cartilage samples from knee replacement patients showed clear signs of regrowth and reduced inflammation after the same treatment.
"We are very excited about this potential breakthrough," said Stanford microbiologist Helen Blau. "Imagine regrowing existing cartilage and avoiding joint replacement."
The findings arrive alongside other promising developments. A 2026 study found that semaglutide, the active ingredient in Ozempic, protects joint cartilage independently of weight loss by reprogramming cartilage cell metabolism. Separately, University of Colorado Boulder researchers are developing an injectable treatment that may reverse osteoarthritis within weeks, with human trials expected within 18 months.
The Stanford team plans to move toward clinical trials, aided by an earlier safety study of a 15-PGDH blocker that raised no significant concerns.The study was published in the journal Science.
