High-Quality Cartilage Production from Pluripotent Stem Cells

High-quality cartilage has been produced from pluripotent stem cells by workers in the laboratory of Sue Kimber and her team in the Faculty of Life Sciences at The University of Manchester. Such success might be used in the future to treat the painful joint condition osteoarthritis.

Kimber and her colleagues used strict laboratory conditions to grow and transform embryonic stem cells into cartilage cells known as chondrocytes.

Professor Kimber said: “This work represents an important step forward in treating cartilage damage by using embryonic stem cells to form new tissue, although it’s still in its early experimental stages.” Kimber’s research was published in Stem Cells Translational Medicine.

During the study, the team analyzed the ability of embryonic stems cells to become cartilage precursor cells. Kimber and her colleagues then implanted these pre-chrondrocytes into cartilage defects in the knee joints of rats. After four weeks, the damaged cartilage was partially repaired and following 12 weeks a smooth surface, which looked very similar to normal cartilage, was observed. More detailed studied of this newly regenerated cartilage demonstrated that cartilage cells from embryonic stem cells were still present and active within the tissue.

Developing and testing this protocol in rats is the first step in generating the information required to run such a study in people with arthritis. Before such a clinical trial can be run, more data will need to be collected in order to check that this protocol is effective and that there are no toxic side-effects.

However, Kimber and her coworkers say that this study is very promising as not only did this protocol generate new, healthy-looking cartilage but also importantly there were no signs of any side-effects such as growing abnormal or disorganized, joint tissue or tumors. Further work will build on this finding and demonstrate that this could be a safe and effective treatment for people with joint damage.

Chondrocytes created from adult stem cells are being used on an experimental basis, but, to date, they cannot be produced in large amounts, and the procedure is expensive.

With their huge capacity to proliferate, pluripotent stem cells such as embryonic stem cells and induced pluripotent stem cells can be manipulated to form almost any type of mature cell. Such cells offer the possibility of high-volume production of cartilage cells, and their use would also be cheaper and applicable to a greater number of arthritis patients, the researchers claim.

“We’ve shown that the protocol we’ve developed has strong potential for developing large numbers of chondrogenic cells appropriate for clinical use,” added Prof Kimber. “These results thus mark an important step forward in supporting further development toward clinical translation.”

Osteoarthritis affects more than eight million people in the UK alone, and is a major cause of disability. It and occurs when cartilage at the ends of bones wears away causing joint pain and stiffness.

Director of research at Arthritis Research UK Dr Stephen Simpson added: “Current treatments of osteoarthritis are restricted to relieving painful symptoms, with no effective therapies to delay or reverse cartilage degeneration. Joint replacements are successful in older patients but not young people, or athletes who’ve suffered a sports injury.

“Embryonic stem cells offer an alternative source of cartilage cells to adult stem cells, and we’re excited about the immense potential of Professor Kimber’s work and the impact it could have for people with osteoarthritis.”