A New Way to Regenerate Joint Tissue
Scientists at Stanford Medicine have discovered a treatment that not only halts cartilage breakdown but actually reverses it — restoring worn joint tissue in older mice and showing striking results in human tissue for the first time.
For millions of people living with joint pain, an announcement from Stanford Medicine on June 12, 2026, may change everything. Researchers have found a way to regenerate lost cartilage and reverse arthritis by blocking a single aging-related protein — a discovery they are calling one of the most significant advances in musculoskeletal medicine in decades.
The treatment targets an enzyme called 15-PGDH, which the team describes as a “gerozyme” — a class of proteins that become more abundant with age and drive tissue decline throughout the body. When researchers blocked this protein in older mice, cartilage that had thinned and weakened with age grew thicker and healthier across the joint surface within weeks.
From Mice to Human Tissue
The findings go further than animal data alone. When researchers applied the same treatment to human knee cartilage samples — collected during joint replacement surgeries — the tissue began producing new, functional cartilage cells. The results in human tissue closely mirrored those seen in the animal models, raising hopes that the approach could translate to actual patients.
“This is a new way of regenerating adult tissue, and it has significant clinical promise for treating arthritis due to aging or injury,” said Professor Helen Blau, director of the Baxter Laboratory for Stem Cell Biology at Stanford and senior author of the study, published in Science. “We were looking for stem cells, but they are clearly not involved. It’s very exciting.”
“Until now, there has been no drug that directly treats the cause of cartilage loss. But this gerozyme inhibitor causes a dramatic regeneration of cartilage beyond that reported in response to any other drug or intervention.” — Professor Nidhi Bhutani, Stanford Medicine
Osteoarthritis is the most common form of arthritis in the United States, affecting roughly one in five adults. The disease gradually breaks down cartilage in the joints, causing pain, stiffness, and swelling that worsens over time. It generates an estimated $65 billion in direct healthcare costs annually, and no approved medication can slow, stop, or reverse the underlying disease process — only manage symptoms, and in severe cases, replace the joint entirely.
Preventing Arthritis After Injury
Beyond regeneration, the treatment showed a remarkable ability to prevent arthritis from developing after joint injuries. Researchers tested the approach in mice modeling ACL tears — a common sports injury seen in soccer, basketball, and skiing that carries a roughly 50 percent lifetime risk of osteoarthritis in the injured joint.
Mice that received the gerozyme inhibitor twice weekly for four weeks after injury were far less likely to develop osteoarthritis. Untreated animals, by contrast, showed elevated 15-PGDH levels and developed joint degeneration within four weeks. The treated mice also walked more normally and placed more weight on the injured limb — a key indicator of preserved joint function.
“Interestingly, prostaglandin E2 has been implicated in inflammation and pain,” Professor Blau noted. “But this research shows that, at normal biological levels, small increases in prostaglandin E2 can promote regeneration.” The treatment works in part by preserving prostaglandin E2 levels — a signaling molecule critical for tissue repair that 15-PGDH otherwise breaks down.
A Pill Instead of a Replacement
Perhaps most significantly, an oral version of the treatment is already being tested in clinical trials for age-related muscle weakness — an existing pathway that, if successful, could accelerate a move toward a joint regeneration pill. Researchers say the treatment could eventually be delivered as a local joint injection or an oral medication, potentially reducing the need for knee and hip replacement surgeries altogether.
The team first identified gerozymes as a class in 2023 and has since linked 15-PGDH to regeneration of bone, nerve, blood, and muscle tissue. The cartilage finding represents the latest — and potentially most impactful — application of this line of research.
The study was published in Science on June 12, 2026. Senior authors are Helen Blau, PhD, and Nidhi Bhutani, PhD, of Stanford Medicine. Lead author is Mamta Singla, PhD, with former postdoctoral scholar Yu Xin (Will) Wang, PhD, now at the Sanford Burnham Prebys Institute.