Stanford Medicine researchers have developed a treatment that blocks a protein associated with aging and managed to restore lost joint cartilage in elderly mice, in addition to preventing the progression of osteoarthritis after joint injuries. The study, published in the journalScience, paves the way for alternatives to total joint replacement, which today is the main solution for serious cases.
Articular cartilage, which acts as a shock absorber in joints, naturally deteriorates with age, trauma or diseases such as osteoarthritis. Until now, available treatments have been limited to pain management or joint replacement surgery, without effectively restoring the original tissue.
Blocking proteins linked to aging
The main target of the new treatment is the enzyme 15-hydroxyprostaglandin dehydrogenase (15-PGDH), whose expression increases with aging. By inhibiting this protein with a small molecular inhibitor (PGDHi), researchers observed significant cartilage regeneration in aged mice.
The tests included both systemic (in the abdomen) and local (directly into the joint) injections. In both cases, the cartilage, which had thinned with age, thickened again, producing functional hyaline tissue—the higher-quality type of articular cartilage, not the less efficient fibrocartilage.
Promising results in human injuries and tissue
In addition to regeneration in aged animals, the treatment prevented the development of osteoarthritis after injuries similar to anterior cruciate ligament (ACL) ruptures, common in athletes and active people. Treated mice maintained better joint function and less pain.
Scientists also tested the inhibitor on human tissue samples obtained from knee replacement surgeries. After a week of exposure, the tissue began to generate new functional cartilage, reducing signs of degradation. This suggests translational potential for humans.
What changes for patients and the healthcare system
Osteoarthritis affects about one in five adults in the United States and costs an estimated $65 billion annually in direct health care alone. A treatment that restores cartilage could drastically reduce the need for prosthetics and improve the quality of life for millions of people with chronic joint pain.
Unlike previous approaches that looked for stem cells, this method reprograms existing chondrocytes (cartilage cells). An oral version of the same inhibitor is already in clinical trials for age-related muscle weakness, which accelerates the prospect of future applications.
Next steps of the research
Led by orthopedic surgery instructor Mamta Singla and former postdoctoral fellow Yu Xin (Will) Wang, with senior authors Helen M. Blau and Nidhi Bhutani, the research advances the understanding of regulators of aging. The authors highlight the surprise with the degree of regeneration observed in elderly animals.
Although still experimental, the study indicates that intervening directly in the aging pathway can rejuvenate tissues that the human body loses the ability to repair naturally.