Molecular Imaging of Stem Cells: Tracking Survival, Biodistribution, Tumorigenicity, and Immunogenicity

Abstract

Being able to self-renew and differentiate into virtually all cell types, both human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs) have exciting therapeutic implications for myocardial infarction, neurodegenerative disease, diabetes, and other disorders involving irreversible cell loss. However, stem cell biology remains incompletely understood despite significant advances in the field. Inefficient stem cell differentiation, difficulty in verifying successful delivery to the target organ, and problems with engraftment all hamper the transition from laboratory animal studies to human clinical trials. Although traditional histopathological techniques have been the primary approach for ex vivo analysis of stem cell behavior, these postmortem examinations are unable to further elucidate the underlying mechanisms in real time and in vivo. Fortunately, the advent of molecular imaging has led to unprecedented progress in understanding the fundamental behavior of stem cells, including their survival, biodistribution, immunogenicity, and tumorigenicity in the targeted tissues of interest. This review summarizes various molecular imaging technologies and how they have advanced the current understanding of stem cell survival, biodistribution, immunogenicity, and tumorigenicity.

The long-term fate of mesenchymal stem cells labeled with magnetic resonance imaging-visible polymersomes in cerebral ischemia

“…18,19 Maintaining long-term survival, accurate homing, and migration of stem cells must first be accomplished before clinical applications in humans. 27 MRI has been the most widely investigated imaging modality for in vivo tracking of the biodistribution and migration of stem cells in a stroke. [9][10][11]23 In our study, MSCs were labeled by using SPION-loaded cationic polymersomes with a relatively low SPION concentration and an obviously short labeling period.…”

Cytosolic Delivery of Nanolabels Prevents Their Asymmetric Inheritance and Enables Extended Quantitative in Vivo Cell Imaging

“…One is to transfect the cells with a reporter gene 2,7 and follow-up on their proliferation through optical imaging, positron emission tomography or magnetic resonance imaging [8][9][10] . This strategy, however, requires a rather time-consuming transfection procedure that may lead to undesired phenotypical alterations and abnormalities in the transplanted cells in comparison to the native cells [11][12][13] . The second strategy is to label the cells with exogenous contrast agents, being either organic probes or inorganic nanoparticles (NPs) 14,15 .…”

Nanodiamonds with silicon vacancy defects for nontoxic photostable fluorescent labeling of neural precursor cells

“…The range of potential applications is diverse, from monitoring drug or tumor localization within the body [1], to assessing the migration of transplanted stem cells used in cell based therapies [2]. A major goal is to develop improved fluorescent labeling reagents that achieve optimal fluorescence intensity without photo-bleaching or blinking.…”