Researchers are investigating the potential of stem cells in cartilage formation

The potential of stem cells in cartilage formation

Researchers at the University of Pennsylvania are investigating new ways to grow cartilage from stem cells. The study, published in the Proceedings of the National Academy of Sciences, is led by Associate Professor Jason Burdick (Department of Bioengineering in the School of Engineering and Applied Science) and Associate Professor Robert Mauck (Department of Orthopaedic Surgery in Penn’s Perelman School of Medicine), and shows that cadherin signal can stimulate chondrogenesis, which can be the starting point for the treatment of several degenerative joint diseases.

It is known that cartilage injuries are very difficult to repair and surgical approaches are currently limited. To repair a damaged cartilage, the surgeon takes a piece of cartilage from another area but this means to harm healthy cartilage which can have consequences later in life (as the person ages). Burdick said that the study aims to discover new methods of production of cartilage to repair small lesions, such as those of athletes and then find ways to get treatment for chronic injuries such as cartilage degradation that occurs with aging. He added that now they are trying to figure out which is the best environment for adult stem cells to produce cartilage. Mauck is optimistic regarding the therapeutic potential of stem cells. He said that the health and vitality of cartilage cells decrease as we age. Therefore the chances that adult chondrocytes to repair cartilage injuries are relatively low, and that stem cells are the solution.

Cartilage

Researchers made several experiments on mesenchymal stem cells, a type of stem cells found in bone marrow that have the ability to differentiate into many cell types such as bone, fat or cartilage. Researchers have focused on finding signals to determine how to differentiate these cells. The first step in the growth of new cartilage consists in initiating chondrogenesis, which implies that the mesenchymal stem cells to differentiate into chondrocytes. Researchers found that an essential role in signal and interaction between these cells  is played by some molecules called cadherins.

To create conditions for growth of cartilage cells, researchers used a peptide sequence that mimics the cadherin interactions, which subsequently helps to differentiate mesenchymal stem cells. Mauck said that while the direct link between cadherin and chondrogenesis is not completely understood, however what is known is that the stimulation of these interactions makes more cartilage. “All together, these experiments provide a thorough demonstration that this cadherin signal can improve the chondrogenesis response when presented from a synthetic hydrogel”, Mauck said.