Page 178 - Cellular Imaging in Regenerative Medicine, Cancer and Osteoarthritis

Chapter 8
in vivo tracking of superparamagnetic iron labelled cells showed some drawbacks especially when cell death, cell migration, cell division and extracellular SPIO accumulation occur simultaneously.
• Besides labelling of cells with iron nanoparticles, cells can also be labelled with a radioactive peptide tracer targeting e.g. a receptor. In this thesis work, we aimed for and achieved a longer circulation time of a radiopeptide by increasing in vivo stability (SB3) or by adding an albumin binding domain to the peptide molecule (Albutate-1). With either concepts one must realise that undesired tracer uptake in healthy organs may increase as well. Therefore this should always also be adequately determined.
• For inflammatory cell imaging we repurposed the currently widely available radiotracer for neuroendocrine tumor imaging ([111In]In-DOTA- TATE, targeting the somatostatin receptor subtype 2) to distinguish between different inflammatory cell subtypes. This marker was elevated on an inflammatory cell subtypes as determined in vitro and in in vivo. Radioactive signal representative of tracer uptake could be measured in vivo in an inflammatory disease model, making this tracer useful for inflammatory cell imaging.
• The challenge for cellular imaging lies in the development/application of the ideal technique. No available imaging technique can currently address all research questions. Therefore, depending on the question(s) addressed, the most suitable technique or combination of techniques, i.e. using multiple modalities, will have to be selected. This will also include the most suitable label for a specific question.
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