Ex vivo expansion of human disc chondrocytes from surgically removed disc tissue: Post-operative tissue stability

Cell therapy using autologous, ex vivo expanded chondrocytes from surgically removed disc tissues has emerged as a promising treatment option for patients with degenerated intervertebral discs. One critical aspect of this is the requirement to culture cells in a good manufacturing practice (GMP)-compliant tissue culture facility. Given the potential for delays during the transportation of disc tissue to a centralized cell culture facility, our study aimed to assess the stability of surgically removed disc tissues stored appropriately for varying durations. Surgically removed disc tissues, stored in normal saline at 4°C for different durations, were cultured in vitro in Dulbecco's Modified Eagle medium (DMEM) supplemented with human platelet lysate. Immunophenotyping was performed using a panel of reported chondrocyte-specific antibodies, including cluster of differentiation 73 (CD73), CD90, CD105, CD166, CD14, human leukocyte antigen DR (HLA-DR), and CD34, for validation. We report that more than 80% of the tissues remained viable up to the 24-h time point as evidenced by cell growth, after which the success of culturing the chondrocytes fell to almost 30% when stored for up to 96 h. The immunophenotype of the cells was identical at all time points. For cell therapy, surgically removed disc tissue should preferably be expanded ex vivo within 24 h post surgery, although all successfully cultured cells, irrespective of the storage duration, expressed the same phenotypic markers. This study will help in planning autologous chondrocyte cell therapy for back pain where the tissue has to be transported to distant GMP facilities.