Stem cell-based therapeutic possibilities have revolutionised medicine. In
order to maximise clinical outcome, it is essential to use the optimal cell type and
dosage, and cell infusion routes, as well as determine the post-transplantation homing
and engraftment efficiency of infused cells. Tracking the fate of transplanted cells is
pivotal to monitoring their viability and distribution to the target organ. Several
labelling techniques are employed to trace transplanted cells in vivo. In rodents,
magnetic-, fluorescence- or luminescence-based imaging methods have been developed
and tested for their capacity to evaluate the engraftment of transplanted cells. The
majority of these modes of in vivo cell tracking are still in the preclinical phase of
investigation. Acquisition of reliable images depends on the specificity of the signal of
the labels used at a certain tissue depth. While longitudinal analysis is feasible in
preclinical models, and usually relies on histological or molecular analyses for its
confirmation, this is still undoable in the clinical setting. Further research in molecular
imaging approaches and in ways to follow the in vivo fate of injected cells in humans
are required.
Keywords: Biodistribution, Bioluminescence, Biomarkers, Cell delivery route,
Cell labelling, Cell tracking, Cornea, Engraftment, Extracellular vesicles,
Fluorescence, Homing, Kidney, Liver, Magnetic resonance imaging,
Mesenchymal stromal/stem cells, Molecular imaging, Nanoparticles-based
tracking, Non-systemic cell delivery, Preclinical research, Systemic cell infusion.
