RESUMO
PURPOSE: The delivery of mesenchymal stem cells (MSCs) to their site of action has remained a technical hurdle for clinical researchers in the expanding field of stem cell-based therapy. The purpose of this study was to test the feasibility of percutaneous image-guided needle delivery of bone marrow-derived human MSCs (hMSCs) to degenerated intervertebral discs (IVDs) in a preclinical model and to assess the containment of these cells within the IVDs. MATERIALS AND METHODS: Degeneration was induced in the lumbar IVDs of four 28-35-kg female pigs. Approximately 100,000 iodine-124 2'-fluoro-2'-deoxy-1ß-D-arabinofuranosyl-5-iodouracil-labeled hMSCs were delivered under fluoroscopic guidance to one of the affected discs in each of the animals. The remaining levels served as internal controls. The animals were imaged by computed tomography (CT) and positron emission tomography (PET) immediately after delivery and 3 days after the procedure. Fifteen days after transplantation, immunohistochemical staining was performed on harvested discs to confirm the presence of delivered hMSCs. RESULTS: After refinement of the technique, PET-CT images on the day of cell transplantation showed initial deposition of the delivered radiolabeled MSCs to the IVD. An additional PET-CT study obtained 3 days later confirmed persistence and containment of activity in the IVD. Findings of histologic evaluation for the presence of human Alu sequences were positive in the treated discs and negative in the controls. CONCLUSIONS: Image-guided needle delivery of MSCs for treatment of degenerated IVDs is feasible as demonstrated in this preclinical model. Trials of this minimally invasive technique in humans are warranted.