In Vivo Myoblasts Tracking Using the Sodium Iodide Symporter Gene Expression in Dogs

Stem cell-based therapies are a promising approach for the treatment of degenerative muscular diseases; however, clinical trials have shown inconclusive and even disappointing results so far. Noninvasive cell monitoring by medicine imaging could improve the understanding of the survival and biodistribution of cells following injection. In this study, we assessed the canine sodium iodide symporter (cNIS) reporter gene as an imaging tool to track by single-photon emission computed tomography (SPECT/CT) transduced canine myoblasts after intramuscular (IM) administrations in dogs. cNIS-expressing cells kept their myogenic capacities and showed strong ^{99 m}Tc-pertechnetate (^{99 m}TcO₄ ^-) uptake efficiency both in vitro and in vivo. cNIS expression allowed visualization of cells by SPECT/CT along time: 4 h, 48 h, 7 days, and 30 days after IM injection; biopsies collected 30 days post administration showed myofiber's membranes expressing cNIS. This study demonstrates that NIS can be used as a reporter to track cells in vivo in the skeletal muscle of large animals. Our results set a proof of concept of the benefits NIS-tracking tool may bring to the already challenging cell-based therapies arena in myopathies and pave the way to a more efficient translation to the clinical setting from more accurate pre-clinical results.