Cartilage-Making Stem Cells from Joints


Chiharo Akazawa from the Tokyo Medical and Dental University and his colleagues have tested two types of mesenchymal stem cells from human patients for their ability to make bone, cartilage, or fat. Their tests illustrated what has been shown several time before; mesenchymal stem cells tend to differentiate into the tissues that most closely resemble their tissue of origin.

Akazawa and his colleagues previously discovered a way to effectively isolated mesenchymal stem cells from bone marrow, which is no small feat because mesenchymal stem cells (MSCs) are a minority of the cells in bone marrow (Mabuchi and others (2013), Stem Cell Reports 1: 152-165). In a recent paper in the journal PLoS ONE, Akazawa and others used this technique to isolate MSCs from bone marrow and from synovial membrane – the fluid-filled sac that encases joints. In large joints, this synovium is large and called a “bursa.”.

In culture, the bone marrow-derived MSCs from several different human donors showed a marked tendency to form bone, but they did not make good cartilage or fat. The synovial MSCs, on the other hand, did not do so well at making bone, but made very good fat and cartilage. These differentiation trends were observed in MSCs culture for several different human donors. All cells were collected during arthroscopic surgery.

Since the synovial membrane of patients suffering from osteoarthritis undergoes, increased cell division, it is possible that the number of stem cells also increases. Alternatively, using MSCs from healthy donors who do not have arthritis may be even more preferable. Nevertheless, MSCs from synovial membrane show excellent cartilage-making potential and they may be a suitable source of cell for cartilage regeneration.

Knee Plica Surgeries


The Regenexx blog has a very interesting article on knee plica surgeries. Knee plicas refer to collisions between the knee cap (patella) and the nearby synovial membrane, which surrounds the joint. The pinching of the synovial membrane irritates it and generates swelling and pain. The common surgical procedure to treat knee plica is to extirpate the irritated synovial membrane. Centeno points out that this portion of the synovial membrane houses a robust stem cell population that helps heal knee problems. Therefore, this procedure might not be the best choice for knee plica. Centeno suggests that the knee is not aligned properly and that realignment of the knee cap could solve the problem without surgery. Read his blog post here and see what you think.