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In vivo Uptake of BrdU, GFP and Iron Oxide Nanoparticles by Local Tissue Macrophages from Labeled Stem Cells. Implications for Cell Transplantation
Author(s) -
Pawelczyk Edyta,
Jordan Eleine Kay,
JohnsonBarelo Janna,
Smith Melissa,
Chaudhry Aneeka,
Frank Joseph Alan
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.578.1
Subject(s) - matrigel , green fluorescent protein , mesenchymal stem cell , fluorescence microscope , transplantation , stem cell , in vivo , flow cytometry , chemistry , microbiology and biotechnology , cell , biology , fluorescence , biochemistry , medicine , gene , physics , surgery , quantum mechanics
There is increasing interest in using exogenous labels (bromodeoxyuridine (BrdU), green fluorescent protein (GFP) or dextran coated iron oxide nanoparticles (SPION) to label cells, to identify transplanted cells and monitor their migration by fluorescent microscopy or in vivo magnetic resonance imaging. Direct implantation of cells into target tissue can result in >70% cell death. Bystander uptake of labeled cells by tissue macrophages (TM) can confound the interpretation of imaging studies. This study investigates the frequency of BrdU, GFP and SPION uptake by TM from labeled cells using a model of angiogenesis and inflammation. Methods: BrdU, GFP, SPION labeled, unlabeled human mesenchymal stromal cells (MSC) were mixed with Matrigel? and implanted over shoulders of mice. Animals (n=72) were euthanized on days 7, 10, 14 post‐implantation and Matrigel? plaques (MPs) dissected and digested. Recovered cells were analyzed by fluorescence microscopy and flow cytometry (FACS) with anti‐CD11b, ‐dextran, ‐GFP or ‐BrdU antibodies. Results: FACS analysis of MPs with BrdU‐labeled MSC revealed 7% of BrdU positive TM, while MPs containing GFP or SPION –labeled MSC had 15% of GFP or dextran positive TM across time points. Conclusions: Direct implantation of labeled stem cells into target tissue can result in about 15 % of label being taken up by macrophages. Care should be taken to validate labeled cells by microscopy.