Regenerating the Meniscus

Researchers have successfully used a scaffold approach to regrow the menicus in a joint:

Researchers have devised a way to replace the knee's protective lining, called the meniscus, using a personalized 3D-printed implant, or scaffold, infused with human growth factors that prompt the body to regenerate the lining on its own. The therapy, successfully tested in sheep, could provide the first effective and long-lasting repair of damaged menisci, which occur in millions of Americans each year and can lead to debilitating arthritis. "At present, there's little that orthopedists can do to regenerate a torn knee meniscus. Some small tears can be sewn back in place, but larger tears have to be surgically removed. While removal helps reduce pain and swelling, it leaves the knee without the natural shock absorber between the femur and tibia, which greatly increases the risk of arthritis."

[The] approach starts with MRI scans of the intact meniscus in the undamaged knee. The scans are converted into a 3D image. Data from the image are then used to drive a 3D printer, which produces a scaffold in the exact shape of the meniscus [made] of polycaprolactone, a biodegradable polymer that is also used to make surgical sutures. The scaffold is infused [with] connective growth factor (CTGF) and transforming growth factor β3 (TGFβ3). [The] sequential delivery of these two proteins attracts existing stem cells from the body and induces them to form meniscal tissue. This is accomplished by encapsulating the proteins in two types of slow-dissolving polymeric microspheres, first releasing CTGF (to stimulate production of the outer meniscus) and then TGFβ3 (to stimulate production of the inner meniscus). Finally, the protein-infused scaffold is inserted into the knee. In sheep, the meniscus regenerates in about four to six weeks. Eventually, the scaffold dissolves and is eliminated by the body.

Link: http://newsroom.cumc.columbia.edu/blog/2014/12/10/3d-printed-meniscus/