Human intervertebral disc cells

Purpose of study: The objective of this study was to investigate how human disc cells in vitro attached, proliferated, produced extracellular matrix (ECM) and expressed selected ECM genes within various three-dimensional (3D) carrier materials. Methods used: Studies were approved by the human subjects institutional review board. Specimens were obtained from surgical procedures performed on individuals with herniated discs. Specimens were transported immediately and cells established using published methods. Control donor discs were obtained by means of the NCI Cooperative Human Tissue Network. Cells were expanded in culture and tested for attachment, proliferation and ECM production in collagen sponges, collagen gel, agarose, alginate or fibrin gel formulations after 10 days of culture. Reverse transcriptase polymerase chain reaction (RT-PCR) in situ hybridization was used to assess ECM gene expression for Types I and II collagen, aggrecan and chondroitin sulfate. Histologic assessment included routine staining and immunohistochemistry. Cell cultures from the annulus were established from 29 individuals (mean age, 45.3 years; range, 26 to 73 years; 17 males, 12 females). Distribution of Thompson grades were grade II, 5 individuals; grade II, 12; grade IV, 12. Twenty-four sites were lumbar, four were cervical and one was lower thoracic. of findings: Collagen sponges provided the best microenvironment for disc cell ECM production ( Fig. 1 , far left) and gene expression ( Fig. 1, A , Type I collagen; B, Type II collagen: C, chondroitin sulfate; D, aggrecan). Although collagen gels supported cell growth, they did not result in either abundant ECM production or ECM gene expression as shown by RT-PCR in situ hybridization. Growth, ECM production and gene expression in alginate, agarose and fibrin microenvironments were also inferior. Relationship between findings and existing knowledge: Cell technologies and tissue engineering techniques have opened new therapeutic possibilities for use of autologous cells in clinical orthopedic applications. For potential biologic intervertebral disc therapies, fundamental questions on how human disc cells interact with and grow in potential cell carriers are unexplored. Overall significance of findings: Results provide novel data on disc cell survival and gene expression within diverse microenvironments. Collagen in a 3D sponge microenvironment proved superior in terms of cell survival, ECM production and ECM gene expression as reflected in assessment of Types I and II collagen, aggrecan and chondroitin sulfate. Disclosures: No disclosures. Conflict of interest: Helen Gruber, and Edward Hanley, Jr., grant research support: North American Spine Society