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Intravital Imaging of Mesenchymal Stem Cell Trafficking and Association With Platelets and Neutrophils

Year: 2014
Type: article
Abstract: Early events of mesenchymal stem/stromal cell (MSC) adhesion to and transmigration through the vascular wall following systemic infusion are important for MSC trafficking to inflamed sites, yet are poorly characterized in vivo. Here, we used intravital confocal imaging to determine the acute extravasation kinetics and distribution of culture-expanded MSC (2-6 hours postinfusion) in a murine model of dermal inflammation. By 2 hours postinfusion, among the MSC that arrested within the inflamed ear dermis, 47.8% ± 8.2% of MSC had either initiated or completed transmigration into the extravascular space. Arrested and transmigrating MSCs were equally distributed within both small capillaries and larger venules. This suggested existence of an active adhesion mechanism, since venule diameters were greater than those of the MSC. Heterotypic intravascular interactions between distinct blood cell types have been reported to facilitate the arrest and extravasation of leukocytes and circulating tumor cells. We found that 42.8% ± 24.8% of intravascular MSC were in contact with neutrophil-platelet clusters. A role for platelets in MSC trafficking was confirmed by platelet depletion, which significantly reduced the preferential homing of MSC to the inflamed ear, although the total percentage of MSC in contact with neutrophils was maintained. Interestingly, although platelet depletion increased vascular permeability in the inflamed ear, there was decreased MSC accumulation. This suggests that increased vascular permeability is unnecessary for MSC trafficking to inflamed sites. These findings represent the first glimpse into MSC extravasation kinetics and microvascular distribution in vivo, and further clarify the roles of active adhesion, the intravascular cellular environment, and vascular permeability in MSC trafficking.
Source: Stem Cells
DOI: 10.1002/stem.1848
Institutions: Brigham and Women's Hospital, Beth Israel Deaconess Medical Center, Harvard University, Massachusetts General Hospital, Harvard–MIT Division of Health Sciences and Technology, Harvard Stem Cell Institute, Massachusetts Institute of Technology, Shanghai Jiao Tong University
Language: English
Field: Medicine
Open Access status: green
Funders: U.S. Department of Defense, Prostate Cancer Foundation, Movember Foundation, National Institutes of Health, National Heart, Lung, and Blood Institute, National Institute of Biomedical Imaging and Bioengineering, National Center for Research Resources
Awards: Microenvironmental control of progenitors in organ dysfunction and repair, Examining firm adhesion and transmigration of surface engineered MSCs, Preparation and Distribution of Adult Stem Cells, Engineered Induction of a Stem Cell Homing Response, G3263630659, G5840191827, Mechanisms for Maintaining Endothelial Integrity During Inflammation, Multi-wavelength femtosecond laser sources for intravital multiphoton microscopy, MESENCHYMAL STEM CELL-BASED THERAPY FOR PROSTATE CANCER, Center for Biomedical OCT Research and Translation
OpenAlex ID: W1555995655
FWCI: 3.752
Cites: 74
Cited by: 73
Related to: 10