Intramyocardial transplantation and tracking of human mesenchymal stem cells in a novel intra-uterine pre-immune fetal sheep myocardial infarction model: a proof of concept study

• Published in: PloS one Vol. 8; no. 3; p. e57759
• Main Authors: Emmert, Maximilian Y, Weber, Benedikt, Wolint, Petra, Frauenfelder, Thomas, Zeisberger, Steffen M, Behr, Luc, Sammut, Sebastien, Scherman, Jacques, Brokopp, Chad E, Schwartländer, Ruth, Vogel, Viola, Vogt, Peter, Grünenfelder, Jürg, Alkadhi, Hatem, Falk, Volkmar, Boss, Andreas, Hoerstrup, Simon P
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 22-03-2013; Public Library of Science (PLoS)
• Subjects: Adipose Tissue - cytology; Animal models; Animals; Biology; Bone marrow; Bone Marrow Cells - cytology; Brain; Cardiomyocytes; Cardiomyopathy; Computed tomography; Cytometry; Disease Models, Animal; Feasibility studies; Female; Fetus - cytology; Fetuses; Gestation; Heart; Heart attack; Heart attacks; Heart diseases; Heart surgery; Hospitals; Humans; Immunohistochemistry; Immunosuppressive agents; Injection; Iron; Kidneys; Laboratory animals; Liver; Lungs; Magnetic resonance imaging; Major histocompatibility complex; Medical imaging; Medicine; Mesenchymal Stem Cell Transplantation - methods; Mesenchymal stem cells; Mesenchyme; Myocardial infarction; Myocardial Infarction - therapy; Neuroimaging; Peritoneum; Pregnancy; Regeneration; Sheep; Skin & tissue grafts; Spleen; Stem cell transplantation; Stem cells; Studies; Therapy; Thymus; Tracking; Transplantation; Uterus; Uterus - cytology; Ventricle; Veterinary Science; France; Switzerland
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0057759

Although stem-cell therapies have been suggested for cardiac-regeneration after myocardial-infarction (MI), key-questions regarding the in-vivo cell-fate remain unknown. While most available animal-models require immunosuppressive-therapy when applying human cells, the fetal-sheep being pre-immune until day 75 of gestation has been proposed for the in-vivo tracking of human cells after intra-peritoneal transplantation. We introduce a novel intra-uterine myocardial-infarction model to track human mesenchymal stem cells after direct intra-myocardial transplantation into the pre-immune fetal-sheep. Thirteen fetal-sheep (gestation age: 70-75 days) were included. Ten animals either received an intra-uterine induction of MI only (n = 4) or MI+intra-myocardial injection (IMI;n = 6) using micron-sized, iron-oxide (MPIO) labeled human mesenchymal stem cells either derived from the adipose-tissue (ATMSCs;n = 3) or the bone-marrow (BMMSCs;n = 3). Three animals received an intra-peritoneal injection (IPI;n = 3; ATMSCs;n = 2/BMMSCs;n = 1). All procedures were performed successfully and follow-up was 7-9 days. To assess human cell-fate, multimodal cell-tracking was performed via MRI and/or Micro-CT, Flow-Cytometry, PCR and immunohistochemistry. After IMI, MRI displayed an estimated amount of 1×10(5)-5×10(5) human cells within ventricular-wall corresponding to the injection-sites which was further confirmed on Micro-CT. PCR and IHC verified intra-myocardial presence via detection of human-specific β-2-microglobulin, MHC-1, ALU-Sequence and anti-FITC targeting the fluorochrome-labeled part of the MPIOs. The cells appeared viable, integrated and were found in clusters or in the interstitial-spaces. Flow-Cytometry confirmed intra-myocardial presence, and showed further distribution within the spleen, lungs, kidneys and brain. Following IPI, MRI indicated the cells within the intra-peritoneal-cavity involving the liver and kidneys. Flow-Cytometry detected the cells within spleen, lungs, kidneys, thymus, bone-marrow and intra-peritoneal lavage, but not within the heart. For the first time we demonstrate the feasibility of intra-uterine, intra-myocardial stem-cell transplantation into the pre-immune fetal-sheep after MI. Utilizing cell-tracking strategies comprising advanced imaging-technologies and in-vitro tracking-tools, this novel model may serve as a unique platform to assess human cell-fate after intra-myocardial transplantation without the necessity of immunosuppressive-therapy.