Embryonic stem cells used for cartilage regeneration

Scientists have described a method to create cartilage from human embryonic stem cells.

Cartilage is a connective tissue in the body with many uses including cushioning joints. When cartilage breaks down due to injury and ageing, it can result in chronic conditions including arthritis. There is no drug available to regenerate cartilage after it has degraded or been damaged and operations on the joint are often required to avoid disability. While surgical techniques exist to replace cartilage damaged by injury with cartilage cell cultured from the patient in the laboratory, removal of cells for the procedure can also cause further damage to the affected joint. Growing cartilage from human embryonic stem cells could avoid this problem.

Co-leader of the study Dr Franchesca Houghton from the Faculty of Medicine at the University of Southampton said: 'This research is exciting as our ability to generate cartilage with properties akin to normal human cartilage has the potential to provide a robust tissue engineered product for cartilage repair.'

Chondrocytes are the only cell-type found in cartilage and they produce collagens and other substances that make up the extracellular matrix in cartilage. In a method described in the journal Scientific Reports researchers differentiated human embryonic stem cells into chondrocytes and then compared how they grew under different conditions and on different media. They then measured the cartilage grown and the transcription of genes involved in the production of collagen.

They found that using the optimal conditions they described they could grow three-dimensional pieces of cartilage measuring up to 6mm across, without any kind of scaffold, a significant improvement on previous attempts which have only grown to 1mm. The cartilage contained chondrocytes as well as type II collagen deposited throughout the extracellular matrix, demonstrating the cartilage had similar structural and mechanical properties to human cartilage.

This means it could potentially be used in surgeries to replace cartilage lost through injury, and restore movement and reduce pain in patients. It is hoped it could provide a longer-lasting treatment than current procedures.

Dr Rahul Tare who co-led the study alongside Dr Houghton explained: 'This tissue-based approach of replacing 'like-for-like' has the potential to constitute a step-change improvement in current cell-based surgical approaches for repairing damaged cartilage and improve long-term patient outcomes.'