Sport is tough on the body, and one of the major health risks from being active is permanent damage to cartilage around the joints. Humans are unable to regenerate cartilage once they are adults and often have to live with painful joints or osteoarthritis, but researchers at Northwestern University are the first to design a bio-active nanomaterial that promotes the growth of new cartilage in vivo and without the use of expensive growth factors. Good new sports fans...
The economic and social impact from damaged cartilage is unknown, but the economic impact of osteoarthritis is estimated to be almost $65 billion in the United States alone. Type II collagen is the major protein in articular cartilage, and comprises the smooth, white connective tissue that covers the ends of bones where they come together to form joints. Until now surgery to regenerate cartilage has involved a procedure called 'microfracture' but this tends to produce a cartilage having predominantly Type I collagen which is more like scar tissue.
In this new minimally-invasive procedure, a bio-active material of nanoscopic fibers stimulates stem cells present in bone marrow to produce cartilage containing type II collagen and repair the damaged joint. The gel is injected to the damaged area of joint where it forms a cohesive solid mimicking what cells normally see and effecting a molecular bind which is essential to the repair and regeneration.
In early trials on animals with cartilage defects, the animals were treated with microfracture, where tiny holes made in the bone beneath the damaged area allow a new blood supply to stimulate new cartilage growth. Implants trialled microfracture alone; microfracture and the nanofiber gel with growth factor added; and microfracture and the nanofiber gel without growth factor added.
Researchers found their technique produced much better results than the microfracture procedure alone, and significantly that addition of expensive growth factor was not required to get the best results. Instead growth factor present in the body appeared to be sufficient to regenerate cartilage because of the molecular design of the gel material. The gel matrix only needs to be present for a month, after which it begins to biodegrade into nutrients and is replaced by natural cartilage.
For the thousands of amateur athletics, professional sportspeople, and elderly people who suffer with joint pain in knees, elbows and shoulders this could be a boon. Used in conjunction with current minimally invasive surgical techniques it could accelerate rehabilitation, and delay or even halt the progression of cartilage lesions into painful degeneration and arthritis. The nanomaterial is being evaluated in a larger preclinical study after which it is hoped the procedure will move to clinical trials.
The Paper "Supramolecular Design of Self-assembling Nanofibers for Cartilage Regeneration" was published by the Proceedings of the National Academy of Sciences (PNAS).