Researchers at Northwestern University have designed a bioactive nanomaterial that promotes the growth of new cartilage in the body’s joints.
Minimally invasive, the therapy activates bone marrow stem cells to produce natural cartilage, no expensive growth factors necessary.
The discovery is important because while bone can grow back, cartilage does not — leaving athletes and other active individuals with “worn out,” painful joints that can’t be rehabilitated by orthopedic surgeons.
Worse, damaged cartilage can lead to loss of physical function and even osteoarthritis. That’s a bad omen for an aging population.
Collagen, specifically Type II, is the major protein in joint (”articular”) cartilage.
“Our material of nanoscopic fibers stimulates stem cells present in bone marrow to produce cartilage containing type II collagen and repair the damaged joint,” said Northwestern professor and study co-author Ramille Shah in a statement. “A procedure called microfracture is the most common technique currently used by doctors, but it tends to produce a cartilage having predominantly type I collagen which is more like scar tissue.”
The researchers’ gel is injected as a liquid to the area of the damaged joint, where it then self-assembles and forms a solid. An extracellular matrix that mimics nature, the gel binds on a molecular level to an important growth factor that helps repair and regenerate cartilage.
By keeping the growth factor concentrated and localized, cartilage cells can regenerate.
To test the nanofiber gel, the researchers implanted it in an animal model with cartilage defects. They also treated them with microfracture, where tiny holes are made in the bone beneath the damaged cartilage to create a new blood supply to stimulate the growth of new cartilage.
Testing in several combinations — microfracture; microfracture and gel; microfracture, gel and growth factor — the scientists found that use of the gel achieved the best results, no growth factor necessary.
It took just one month for the matrix to stimulate cartilage growth.
Based on self-assembling molecules called peptide amphiphiles, the matrix then biodegrades into nutrients, replaced by natural cartilage.
Their results were published by the Proceedings of the National Academy of Sciences.
