Bone Grafts Research Today is a free monthly online journal that collates and summarizes the latest research about Bone Grafts, including details on spine fusion, surgery, procedure, risks. | ||||||||
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Imaging of Mesenchymal Stem Cell Transplant by Bioluminescence and PET.Love Z, Wang F, Dennis J, Awadallah A, Salem N, Lin Y, Weisenberger A, Majewski S, Gerson S, Lee Z Department of Nuclear Medicine/Radiology, University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, Ohio; 2Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio; 3Department of Orthopaedics, Case Western Reserve University, Cleveland, Ohio; 4Center for Stem Cell and Regenerative Medicine, Case Western Reserve University, Cleveland, Ohio; 5Department of Hematology/Oncology, Case Western Reserve University, Cleveland, Ohio; and 6Thomas Jefferson National Accelerator Facility, Newport News, Virginia. Dynamic measurements of infused stem cells generally require animal euthanasia for single-time-point determinations of engraftment. In this study, we used a triple-fusion reporter system for multimodal imaging to monitor human mesenchymal stem cell (hMSC) transplants. METHODS: hMSCs were transduced with a triple-fusion reporter, fluc-mrfp-ttk (encoding firefly luciferase, monomeric red fluorescent protein, and truncated herpes simplex virus type 1 sr39 thymidine kinase) by use of a lentiviral vector. Transduced cells were assayed in vitro for the expression of each functional component of the triple-fusion reporter. Transduced and control hMSCs were compared for their potential to differentiate into bone, cartilage, and fat. hMSCs expressing the reporter were then loaded into porous, fibronectin-coated ceramic cubes and subcutaneously implanted into NOD-SCID mice along with cubes that were loaded with wild-type hMSCs and empty cubes. Mice were imaged repeatedly over 3 mo by bioluminescence imaging (BLI), and selected animals underwent CT and PET imaging. RESULTS: Osteogenic, adipogenic, and chondrogenic potential assays revealed retained differentiation potentials between transduced and wild-type hMSCs. Signals from the cubes loaded with reporter-transduced hMSCs were visible by BLI over 3 mo. There was no signal from the empty or wild-type hMSC-loaded control cubes. PET data provided confirmation of the quantitative estimation of the number of cells at one spot (cube). Cubes were removed from some animals, and histologic evaluations showed bone formation in cubes loaded with either reporter-transduced or wild-type hMSCs, whereas empty controls were negative for bone formation. CONCLUSION: The triple-fusion reporter approach resulted in a reliable method of labeling stem cells for investigation in small-animal models by use of both BLI and small-animal PET imaging. It has the potential for translation into future human studies with clinical PET. Published 6 December 2007 in J Nucl Med, 48(12): 2011-2020.
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