Young Human Chondrocytes expansion in the Quantum® Hollow-Fibre Bioreactor

Charlotte Hulme, John Garcia, Claire Mennan, Sally Roberts, Robert Freeman, Nigel Kiely, Derfel Williams and Karina Wright

Funded by the Medical Research Council

The Quantum® bioreactor (see figure 1) is an automated hollow fibre system, which has an internal surface area of 2.1m2 (equivalent to 120 T-175 tissue culture flasks), allowing large scale expansion of cells. Our group has used this bioreactor system to grow stem cells from human bone marrow and umbilical cords and has compared the characteristics of these cells to the standard tissue culture plastic technique (TCP), with the aim of using these cells in cell therapies for example, for cartilage repair.

More recently, we have looked at expanding cells from the cartilage, called chondrocytes, in this system. This is because large numbers of chondrocytes will be required to treat cartilage defects, especially is using an allogeneic (donor source) therapy. Also improving cost-effectiveness and batch[1]to-batch variations of the cells. To date, we have expanded adult chondrocytes from 5 donors who were undergoing total knee replacements. Following 10 million cells being seeded into the bioreactor, an average of 86 million chondrocytes could be harvested in 8 days. These cells retained the same characteristics as matched cells grown using standard TCP conditions, importantly maintaining the same ability to form cartilage.

We are currently looking at alternative sources of donor cartilage, which are likely to have capacity to grow well and to repair cartilage. As children, our cells have a better ability to form cartilage, as part of the natural aging/growing process. Therefore, we have identified sources of cartilage from infants aged 4 and under, which are collected with informed patient consent. These include from children born with extra fingers or toes (called polydactyly) that are being surgically removed or from the hip growth plate (called the iliac apophysis) of children being treated for hip misalignment. We have now grown cells from 4 polydactyly (see figure 2), and 4 iliac apophysis donors in the Quantum® bioreactor and compared these to standard culture conditions. The greatest number of cells can be yielded from the bioreactor from the polydactyly digits (average 85 million cells). Further characterisation of the cells is being completed to determine which juvenile donor source has the greatest potential for future clinical use.