ABSTRACT: Stem cell and other cell-based therapies have emerged as potential, novel treatment options for a wide range of diseases including acute myocardial infarction and severe heart failure. 1–5 Ensuring the delivery of a sufficient number of cells to the target site is critical to the devel-opment and assessment of these therapies. Several meth-ods have been proposed for tracking cells in vivo, but their translation into the clinical setting has been hampered for many reasons including limitations of the imaging modality in humans and the failure of reagents to comply with Good Manufacturing Practice (GMP) standards: a prerequisite for clinical use. Background—Cell therapy is an emerging and exciting novel treatment option for cardiovascular disease that relies on the delivery of functional cells to their target site. Monitoring and tracking cells to ensure tissue delivery and engraftment is a critical step in establishing clinical and therapeutic efficacy. The study aims were (1) to develop a Good Manufacturing Practice–compliant method of labeling competent peripheral blood mononuclear cells with superparamagnetic particles of iron oxide (SPIO), and (2) to evaluate its potential for magnetic resonance cell tracking in humans. Methods and Results—Peripheral blood mononuclear cells 1–5×10 9 were labeled with SPIO. SPIO-labeled cells had similar in vitro viability, migratory capacity, and pattern of cytokine release to unlabeled cells. After intramuscular administration, up to 10 8 SPIO-labeled cells were readily identifiable in vivo for at least 7 days using magnetic resonance imaging scanning. Using a phased-dosing study, we demonstrated that systemic delivery of up to 10 9 SPIO-labeled cells in humans is safe, and cells accumulating in the reticuloendothelial system were detectable on clinical magnetic resonance imaging. In a healthy volunteer model, a focus of cutaneous inflammation was induced in the thigh by intradermal injection of tuberculin. Intravenously delivered SPIO-labeled cells tracked to the inflamed skin and were detectable on magnetic resonance imaging. Prussian blue staining of skin biopsies confirmed iron-laden cells in the inflamed skin. Conclusions—Human peripheral blood mononuclear cells can be labeled with SPIO without affecting their viability or function. SPIO labeling for magnetic resonance cell tracking is a safe and feasible technique that has major potential for a range of cardiovascular applications including monitoring of cell therapies and tracking of inflammatory cells. (Circ Cardiovasc Imaging. 2012;5:509-517.) Clinical Trial Registration—URL: http://www.clinicaltrials.gov; Unique identifier: NCT00972946, NCT01169935.
Circulation Cardiovascular Imaging 07/2012; 5:509-517. · 5.94 Impact Factor