Molecular Imaging of Stem Cells

Abstract

Regenerative medicine with the use of stem cells has appeared as a potential therapeutic alternative for many disease states. Despite initial enthusiasm, there has been relatively slow transition to clinical trials. In large part, numerous questions remain regarding the viability, biology and efficacy of transplanted stem cells in the living subject. The critical issues highlighted the importance of developing tools to assess these questions. Advances in molecular biology and imaging have allowed the successful non-invasive monitoring of transplanted stem cells in the living subject. Over the years these methodologies have been updated to assess not only the viability but also the biology of transplanted stem cells. In this review, different imaging strategies to study the viability and biology of transplanted stem cells are presented. Use of these strategies will be critical as the different regenerative therapies are being tested for clinical use.

Noninvasive in vivo cell tracking using molecular imaging: A useful tool for developing mesenchymal stem cell-based cancer treatment

“…HSV1-tk, being a viral protein, is immunogenic; therefore, it is the target of the host immune system, leading to further reduction in sensitivity of the reporter protein. Proteins of mammalian origin including dopamine receptor and mitochondrial tk have been developed as nuclear medicine reporter genes to avoid this issue[ 61 ]. Probes [ e.g.…”

“…The use of mutant dopamine receptor rather than the wild-type protein is suggested for the prevention of the subsequent biological response, but it will still be able to bind to the probe. The drawback of this strategy is that it produces a limited signal because of the interaction of the receptor with only one ligand molecule[ 61 ]. In one study, authors transplanted human MSCs, expressing a mutated version of the dopamine type 2 receptor into athymic rats.…”

“…Following the administration of another NIS probe, 131 I, which emits cytotoxic beta rays, the tumor regressed[ 64 ]. Other examples of nuclear medicine reporter genes utilized with PET and SPECT imaging include the neurotensin receptor subtypes, the somatostatin receptor, and cytosine deaminase[ 61 ]. The use of hybrid reporter genes enables in vivo imaging of MSCs with multimodal approaches[ 65 ].…”

Exploring the future of regenerative medicine: Unveiling the potential of optical microscopy for structural and functional imaging of stem cells

“…In conventional medical imaging methods, samples will be combined with special labels to enhance the contrast. The tissue sample can be labeled with a radionucleotide for SPECT and PET, and superparamagnetic iron oxide particles for MRI [10]. However, these methods are extra‐expensive and have a low spatial resolution.…”

Nanotechnology in Immunotherapy for Type 1 Diabetes: Promising Innovations and Future Advances

“…This can permit both short term and longitudinal monitoring of the transplant in the patient and allow for timely intervention, as is the case in many post-transplant graft loss incidents [ 155 ]. It can also allow for the visualization of certain molecular (bio)markers that can indicate the existence of specific cellular states or functions [ 156 , 157 , 158 ].…”