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Chaudeurge A.,French Institute of Health and Medical Research | Wilhelm C.,CNRS Complex Systems and Materials Laboratory | Wilhelm C.,University Paris Diderot | Chen-Toumoux A.,French Institute of Health and Medical Research | And 16 more authors.
Cell Transplantation | Year: 2012

Therapeutic intracavitary stem cell infusion currently suffers from poor myocardial homing. We examined whether cardiac cell retention could be enhanced by magnetic targeting of endothelial progenitor cells (EPCs) loaded with iron oxide nanoparticles. EPCs were magnetically labeled with citrate-coated iron oxide nanoparticles. Cell proliferation, migration, and CXCR4 chemokine receptor expression were assessed in different labeling conditions and no adverse effects of the magnetic label were observed. The magnetophoretic mobility of labeled EPCs was determined in vitro, with the same magnet as that subsequently used in vivo. Coronary artery occlusion was induced for 30 min in 36 rats (31 survivors), followed by 20 min of reperfusion. The rats were randomized to receive, during brief aortic cross-clamping, direct intraventricular injection of culture medium (n = 7) or magnetically labeled EPCs (n = 24), with (n = 14) or without (n = 10) subcutaneous insertion of a magnet over the chest cavity (n = 14). The hearts were explanted 24 h later and engrafted cells were visualized by magnetic resonance imaging (MRI) of the heart at 1.5 T. Their abundance in the myocardium was also analyzed semiquantitatively by immunofluorescence, and quantitatively by real-time polymerase chain reaction (RT-PCR).Although differences in cell retention between groups failed to be statistically significant using RT-PCR quantification, due to the variability of the animal model, immuno-staining showed that the average number of engrafted EPCs was significantly ten times higher with than without magnetic targeting. There was thus a consistent trend favoring the magnet-treated hearts, thereby suggesting magnetic targeting as a potentially new mean of enhancing myocardial homing of intravascularly delivered stem cells. Magnetic targeting has the potential to enhance myocardial retention of intravascularly delivered endothelial progenitor cells. © 2012 Cognizant Comm. Corp.

Kalfa D.,French Institute of Health and Medical Research | Bel A.,Assistance Publique Hopitaux de Paris APHP | Chen-Tournoux A.,French Institute of Health and Medical Research | Della Martina A.,Bioring Inc. | And 10 more authors.
Biomaterials | Year: 2010

A major issue in congenital heart surgery is the lack of viable right ventricular outflow tract (RVOT) replacement materials. Several biomaterials have been used, with different scaffolds and cells, but they have failed to restore a tri-layered RVOT, and reoperations are often required. We investigated the function, histological changes and potential of growth and tissue regeneration of polydioxanone (PDO) electrospun bioabsorbable valved patches seeded with mesenchymal stem cells (MSCs) in the RVOT of growing lambs. Autologous blood-derived MSCs were labeled with quantum dots and seeded on PDO electrospun valved patches. Those were implanted into the RVOT of 6 growing lambs followed up until 8 months. Results were assessed by echocardiography, magnetic resonance imaging (MRI), histology, immunohistochemistry and biochemical assays. Tissue-engineered RVOT were neither stenotic nor aneurismal and displayed a growth potential, with less fibrosis, less calcifications and no thrombus compared with control polytetrafluoroethylene (PTFE)-pericardial patches. The PDO scaffold was completely degraded and replaced by a viable, three-layered, endothelialized tissue and an extracellular matrix with elastic fibers similar to that of native tissue. Detection of quantum dots at 1 month suggested that at least some of the cells were-derived from the grafted cells. A polydioxanone electrospun tissue-engineered valved transannular patch seems to be a promising device in restoring a living RVOT and could ultimately lead to applications in the treatment of congenital RVOT diseases. © 2010 Elsevier Ltd. All rights reserved.

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