A promising new study suggests that blocking a single age-linked enzyme could help regenerate damaged cartilage, reduce pain and potentially transform treatment for osteoarthritis, a condition that affects mobility in millions of people worldwide.
Researchers reported in Science that inhibiting the enzyme 15-hydroxy prostaglandin dehydrogenase (15-PGDH) led to substantial cartilage repair in both aged mice and younger mice with injury-related osteoarthritis. The same approach also showed encouraging results in human cartilage samples taken from patients undergoing knee replacement surgery.
“Osteoarthritis is a common debilitating disease that is difficult to treat effectively,” the researchers wrote, noting that there are currently “limited effective disease modifying therapies for OA that restore cartilage function” and that most treatment options are restricted to “pain management or eventual joint replacement.”
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Cartilage, which cushions joints and enables smooth movement, has long been considered one of the body’s least regenerative tissues. As it wears away with age or injury, joints become painful, inflamed and stiff.
The research team focused on 15-PGDH after earlier work linked the enzyme to aging in muscle tissue. In the new study, they found that 15-PGDH expression increases in aged and injured cartilage, raising the possibility that it contributes to joint degeneration as well.
“We observed increased 15-PGDH expression in aged and injured cartilage and postulated that inhibition of 15-PGDH with a small-molecule drug would lead to cartilage regeneration,” the study said.
That theory was tested using a specially designed inhibitor, referred to as PGDHi.
The results were striking. According to the researchers, “short-term systemic or local inhibition of 15-PGDH with a small-molecule inhibitor led to extensive cartilage regeneration.”
Importantly, the repaired tissue was not inferior scar-like cartilage. Instead, the regenerated tissue was true hyaline articular cartilage, the smooth, resilient material that naturally lines healthy joints.
The study said: “Notably, the regenerated cartilage was hyaline articular cartilage, not functionally inferior fibrocartilage.”
That distinction matters because many previous repair attempts have produced fibrocartilage, which lacks the durability and mechanical properties of normal joint cartilage.
The treatment also appeared to reduce pain — one of the most disabling symptoms of osteoarthritis.
“Pain, the most common clinical symptom of OA, was diminished in three well-established assays,” the researchers reported.
The mechanism behind the improvement may involve restoring balance inside the joint rather than merely suppressing symptoms.
Scientists found that the inhibitor changed the makeup of cartilage cells. It reduced harmful hypertrophic-like and fibrogenic chondrocytes while increasing healthier articular chondrocytes that produce extracellular matrix, the structural material essential for cartilage strength and function.
“PGDH inhibitor treatment caused a change in chondrocyte composition of the OA joint,” the paper said, leading to “an increase in articular chondrocytes that secrete extracellular matrix essential to cartilage function.”
One of the most surprising findings was that regeneration did not rely on stem cells, a common focus of earlier cartilage-repair strategies.
Instead, “cartilage regeneration appears to occur through gene expression changes in preexisting chondrocytes, rather than stem or progenitor cell proliferation.”
That means the body’s existing cartilage cells may be reprogrammed into a healthier state.
Researchers said this could represent an entirely new therapeutic pathway for joint disease.
“Our findings highlight that inhibition of 15-PGDH — an enzyme that drives tissue aging, a ‘gerozyme’ — leads to cartilage regeneration in aged mouse OA joints, in joints of young adult mice with posttraumatic OA resulting from an ACL tear, and in human OA patient-derived joint explants.”
The study is especially relevant for athletes and active adults because anterior cruciate ligament (ACL) injuries often lead to post-traumatic osteoarthritis later in life. In mice with ACL-related injury, the inhibitor helped prevent the expected progression of the disease.
Human tissue samples also showed similar beneficial cellular changes, strengthening hopes that the findings may translate into future treatments.
The researchers said these results “underscore the clinical potential of the small-molecule 15-PGDH inhibitor as a therapeutic candidate for OA.”
Because the drug is highly specific and can be delivered directly to the joint, they believe it may be well suited for clinical development.
They concluded that inhibiting 15-PGDH “represents a new therapeutic approach for OA that is readily amenable to translation to the clinic.”
Much more testing is needed before the treatment reaches patients. But if future trials confirm the findings, the approach could one day help people avoid chronic pain, preserve mobility and delay — or even prevent — knee and hip replacements.
This story is done in collaboration with First Check, which is the health journalism vertical of DataLEADS.
