Successful in vivo MRI tracking of MSCs labeled with Gadoteridol in a Spinal Cord Injury experimental model

- Compared to isotonic incubations, the hypo-osmotic labeling enhances the MRI of cells.
- The hypo-osmolarity significantly supports the agent uptake and contrast generation.
- The MSC-transplantation imaging in SCI mice is improved by simple labeling expedients.
- The migration of 3.0 × 105 labeled MSCs is reliably tracked in vivo for 10 days.
- The biological profile and therapeutic effect of labeled MSCs are preserved.

In this study, murine Mesenchymal Stem Cells (MSCs) labeled with the clinically approved MRI agent Gadoteridol through a procedure based on the hypo-osmotic shock were successfully tracked in vivo in a murine model of Spinal Cord Injury (SCI). With respect to iso-osmotic incubations, the hypo-osmotic labeling significantly increased the Gd3 + cellular uptake, and enhanced both the longitudinal relaxivity (r1) of the intracellular Gadoteridol and the Signal to Noise Ratio (SNR) measured on cell pellets, without altering the biological and functional profile of cells. A substantial T1 Contrast Enhancement after local transplantation of 3.0 × 105 labeled cells in SCI mice enabled to follow their migratory dynamics in vivo for about 10 days, and treated animals recovered from the motor impairment caused by the injury, indicating unaltered therapeutic efficacy. Finally, analytical and histological data corroborated the imaging results, highlighting the opportunity to perform a precise and reliable monitoring of the cell-based therapy.