Labeling Protocols for In Vivo Tracking of Human Skeletal Muscle Cells (HSkMCs) by Magnetic Resonance and Bioluminescence Imaging

Purpose: We propose herein labeling protocols for multimodal in vivo visualization of human skeletal muscle cells (HSkMCs) by MRI and BLI to investigate the survival, localization, and proliferation/differentiation of these cells in cell-mediated therapy. Procedures: HSkMCs were labeled with different quantities of Endorem (R) and transfection agents or infected with lentiviral vector expressing the luciferase gene under the myogenin promoter. Cells were evaluated before and after intra-arterial injection in NUDE mice with N-2-induced muscle inflammation. Results: Neither iron labeling nor infection affected cell features; the number of iron-positive cells increased proportionally to the iron content in the medium and in the presence of transfection agents. Loaded cells were detected for up to 1 month by MRI and 2 months by BLI. Conclusions: These protocols could be used to visualize new stem cells, in vivo and over time, in preclinical studies of cell-based treatments for myopathies of different etiologies.