Stem cells could regenerate cartilage lost through injury or disease

Osteoarthritis affects approximately 3.8% of people worldwide and almost 15% of people over the age of 60. Because stem cells have the potential to regenerate damaged tissue, researchers are looking at using mesenchymal stem cells from cord blood to treat osteoarthritis.

Osteoarthritis is a bone disease caused by the breakdown of cartilage, the connective tissue found between bones. Symptoms of osteoarthritis develop slowly, but they progressively worsen over time. Characteristic symptoms include joint pain, tenderness, stiffness, loss of flexibility and a feeling of bones grating against each other.

Once diagnosed, treating osteoarthritis involved effectively managing the symptoms, including medication to manage pain, physical therapy or surgery. However, these methods are not able to reverse the damage to the cartilage. Hence they will not ‘cure’ the underlying cause of osteoarthritis. This is why researchers from around the world are looking at using stem cells, particularly mesenchymal stem cells, as a way to regenerate cartilage.

In one such study published online in the journal Stem Cells Translational Medicine, scientists obtained mesenchymal stem cells from human umbilical cord blood. They then supplemented the stem cells with a gel containing hyaluronic acid, a type of molecule normally found in cartilage and connective tissue.

The mixture of stem cells and hyaluronic acid were transplanted into knees of miniature pigs that had sustained knee injuries. When they looked at these pigs twelve weeks after the treatment, they observed greater and more complete regeneration of cartilage compared to the pigs with injured knees that did not receive the stem cell transplant.

In the knees receiving the stem cells, the surface of the injury sites were relatively smooth as in a healthy joint, and cells in the treated area appeared similar to cells in the surrounding normal cartilage. Furthermore, there were no signs of rejection or infection in any of the animals.

Mesenchymal stem cells from cord blood are readily obtained and can be stored long-term, thus providing an attractive alternative to conventional knee and hip replacement surgeries. In recent years, the cartilage regeneration potential of mesenchymal stem cells has been investigated in rats and rabbits. This study provides further support for such treatments using a larger animal that is physiologically similar to humans.

Reference:
Ha, CW, Park, Y, Chung, J, et al. (2015) Cartilage repair using composites of human umbilical cord blood-derived mesenchymal stem cells and hyaluronic acid hydrogel in a minipig model. Stem Cells Translational Medicine. 4(9): 1044–1051. doi: 10.5966/sctm.2014-0264