Researchers of the UT's MIRA Research Institute have managed to grow stable cartilage from stem cells in a laboratory. This cartilage remains cartilage when transplanted into the body. So far, the cartilage derived from stem cells, was converted into bone tissue soon after transplantation. The trick is to grow the cells at a low oxygen concentration. This fundamental research, which is published by the leading scientific journal PNAS, brings us one step closer to the treatment of cartilage diseases such as arthrosis.
In the Netherlands, more than one million people suffer from cartilage diseases such as arthrosis: a deterioration or even complete loss of joint cartilage. Inserting new cartilage made from a patient's own stem cells could offer a solution. So far, however, researchers were unable to grow cartilage from stem cells which, once transplanted into the body, actually remained cartilage. Inside the body stem cells derived cartilage was always automatically converted into bone tissue, which prevents the healing of cartilage diseases.
Low oxygen concentration
Researchers from the University of Twente have been the first to grow cartilage from stem cells which also remains cartilage after transplantation in a mouse. They were able to do so by growing the cells at a low oxygen concentration of 2.5 percent, explains professor Marcel Karperien (professor of Developmental BioEngineering). The golden standard for growing cartilage was always an oxygen concentration of 21 percent, just as in the outside air, but this is, in fact, not natural. Oxygen concentrations are much lower inside the body and even more inside cartilage, as cartilage lacks blood vessels.”
Due to an investment in new facilities, professor Karperien and his colleagues were able to grow stem cells and have them differentiate into cartilage at a lower oxygen tension. This cartilage was transplanted into mice and was not converted into bone tissue, while the cartilage from the control group was fully replaced by bone tissue after five weeks. Professor Karperien: “After this publication, I expect all laboratories focusing on cartilage research and cartilage tissue engineering to buy a special incubator in which they can grow their stem cells at a low oxygen concentration.”
Mr Karperien believes that this is an important step for research into the treatment of cartilage diseases and bone defects using a patient's own stem cells. “By playing with environmental factors during growth and differentiation of stem cells, we can partly determine how they will develop and behave in our body.” The researchers now want to understand the underlying mechanisms in order to slow down or prevent arthritis, among other things, and to enhance the growing of cartilage for tissue transplants.
The research was conducted within the Developmental BioEngineering department of the UT's MIRA Research Institute and was financially supported by the Ministry of Economic Affairs, the Ministry of Education, Culture and Science and the Dutch Arthritis Association.