(CN) — Scientists at Northwestern University created a bioactive material that regenerates cartilage in knee joints, according to a study published Monday, an innovation that could be used to prevent knee replacement surgeries, treat osteoarthritis and repair sports injuries like ACL tears.
“When cartilage becomes damaged, it can greatly impact health and mobility. The problem is that adult human cartilage doesn’t naturally heal. Our new therapy can induce repair in tissue that doesn’t naturally regenerate,” lead researcher Samuel Stupp said in a press release.
The material, a complex network of molecules, mimics cartilage’s natural environment. It includes a bioactive peptide that binds to transforming growth factor beta-1 (TGFb-1), which is crucial for cartilage growth, and modified hyaluronic acid, a substance found in cartilage and joint fluid.
“Many people are familiar with hyaluronic acid from skincare products,” Stupp said. “It’s also naturally found in joints. We chose it because it resembles the natural polymers in cartilage.”
The researchers tested the material in sheep with cartilage defects in their stifle joints, which are similar to human knees. Like human cartilage, sheep cartilage is also tough to regenerate. After six months, the team observed the growth of new cartilage containing natural biopolymers, collagen II and proteoglycans. Biopolymers are essential for pain-free joint movement.
“A study on a sheep model is more predictive of how the treatment will work in humans,” Stupp said. “In other smaller animals, cartilage regeneration occurs much more readily.”
Stupp’s team combined the bioactive peptide and modified hyaluronic acid to form nanoscale fibers that mimic cartilage’s architecture. The fibers create a scaffold for the body’s cells to regenerate cartilage tissue while the bioactive signals encourage cartilage repair.
Researchers injected the thick, paste-like material into cartilage defects, where it transformed into a rubbery matrix. As the scaffold degraded, new cartilage grew to fill the defect. The new cartilage was consistently higher quality than the control, according to the study, published in the Proceedings of the National Academy of Sciences.
Stupp envisions the material being used in open-joint or arthroscopic surgeries. The standard treatment is microfracture surgery, which often results in fibrocartilage and is less effective than hyaline cartilage for joint function, Stupp said.
“By regenerating hyaline cartilage, our approach should better resist wear and tear, improving mobility and reducing pain long-term without needing large hardware for joint reconstruction,” he added.
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