Stanford scientists regrow lost cartilage and reverse arthritis in major breakthrough | ScienceDaily

Science News

from research organizations

Stanford scientists regrow lost cartilage and reverse arthritis in major breakthrough

Scientists may have found a way to regrow aging cartilage and stop arthritis before it starts, potentially making joint replacements far less common.

Date:<br>June 12, 2026<br>Source:<br>Stanford Medicine<br>Summary:<br>A new treatment that blocks an aging-related protein restored lost cartilage in old mice and helped prevent arthritis after knee injuries. Human cartilage samples showed similar signs of regeneration, raising hopes for a future drug that could repair joints instead of replacing them.<br>Share:

Facebook<br>Twitter<br>Pinterest<br>LinkedIN<br>Email

FULL STORY

Scientists have found a way to regenerate worn-out joint cartilage by blocking an aging-related protein called 15-PGDH. Credit: Shutterstock

A treatment that targets a protein linked to aging has restored lost knee cartilage in older mice and prevented arthritis from developing after serious joint injuries, according to a Stanford Medicine-led study.

Researchers also found encouraging results in human tissue. Samples collected during knee replacement surgeries began producing new, functional cartilage when exposed to the treatment.

The findings raise the possibility that damaged cartilage caused by aging or osteoarthritis could one day be repaired with either a local injection or an oral medication. If successful in people, the approach could reduce the need for knee and hip replacement surgeries.

An oral version of the treatment is already being tested in clinical trials for age-related muscle weakness.

Targeting the Root Cause of Osteoarthritis

Osteoarthritis is the most common form of arthritis and affects about one in five adults in the United States. The disease gradually breaks down cartilage in the joints, causing pain, stiffness, and swelling. It is estimated to generate roughly $65 billion in direct health care costs each year.

Current treatments focus mainly on pain relief and, in severe cases, joint replacement surgery. No approved medication can slow, stop, or reverse the underlying disease process.

The new treatment works by blocking a protein called 15-PGDH, which researchers describe as a "gerozyme." This class of proteins becomes more abundant with age and contributes to declining tissue function throughout the body.

The same research team first identified gerozymes in 2023. Previous studies showed that 15-PGDH plays a major role in age-related muscle decline in mice. When researchers block the protein, older animals gain muscle mass and endurance. When the protein is artificially increased in young mice, their muscles become weaker and smaller.

Scientists have also linked 15-PGDH to the regeneration of bone, nerve, and blood cells.

A Different Type of Tissue Regeneration

In many tissues, regeneration occurs because stem cells multiply and develop into new specialized cells. Cartilage appears to work differently.

Instead of relying on stem cells, cartilage-producing cells called chondrocytes seem able to shift their gene activity and return to a more youthful state.

"This is a new way of regenerating adult tissue, and it has significant clinical promise for treating arthritis due to aging or injury," said Helen Blau, PhD, professor of microbiology and immunology. "We were looking for stem cells, but they are clearly not involved. It's very exciting."

Blau, director of the Baxter Laboratory for Stem Cell Biology and the Donald E. and Delia B. Baxter Foundation Professor, and Nidhi Bhutani, PhD, associate professor of orthopedic surgery, are the senior authors of the study, which was published in Science. Instructor of orthopedic surgery Mamta Singla, PhD, and former postdoctoral scholar Yu Xin (Will) Wang, PhD, are the lead authors. Wang is now an assistant professor at the Sanford Burnham Institute in San Diego.

Remarkable Cartilage Regrowth

"Millions of people suffer from joint pain and swelling as they age," Bhutani said. "It is a huge unmet medical need. 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."

The human body contains three main forms of cartilage. Elastic cartilage provides flexibility in structures such as the outer ear. Fibrocartilage is tough and shock-absorbing, found in places like the discs between vertebrae. Hyaline cartilage is smooth and slippery, allowing joints such as the knees, hips, shoulders, and ankles to move freely.

Osteoarthritis primarily damages hyaline cartilage, also called articular cartilage.

As joints age or experience injury or excess stress from obesity, chondrocytes begin producing inflammatory molecules and breaking down collagen, the main structural component of cartilage. As collagen...