Assessment of human MAPCs for stem cell transplantation and cardiac regeneration after myocardial infarction in SCID mice
Received 4 February 2010; received in revised form 30 June 2010; accepted 30 June 2010. published online 12 July 2010. Uncorrected Proof
Objective
Clinical studies suggest that transplantation of total bone marrow (BM) after myocardial infarction (MI) is feasible and potentially effective. However, focusing on a defined BM-derived stem cell type may enable a more specific and optimized treatment. Multilineage differentiation potential makes BM-derived multipotent adult progenitor cells (MAPCs) a promising stem cell pool for regenerative purposes. We analyzed the cardioregenerative potential of human MAPCs in a murine model of myocardial infarction.
Materials and Methods
Human MAPCs were selected by negative depletion of CD45+/glycophorin+ BM cells and plated on fibronectin-coated dishes. In vitro, stem cells were analyzed by reverse transcription polymerase chain reaction. In vivo, we transplanted human MAPCs (5 × 105) by intramyocardial injection after MI in severe combined immunodeficient (SCID) beige mice. Six and 30 days after the surgical procedure, pressure-volume relationships were investigated in vivo. Heart tissues were analyzed immunohistochemically.
Results
Reverse transcription polymerase chain reaction experiments on early human MAPC passages evidenced an expression of Oct-4, a stem cell marker indicating pluripotency. In later passages, cardiac markers (Nkx2.5, GATA4, MLC-2v, MLC-2a, ANP, cTnT, cTnI,) and smooth muscle cell markers (SMA, SM22α) were expressed. Transplantation of human MAPCs into the ischemic border zone after MI resulted in an improved cardiac function at day 6 (ejection fraction, 26% vs 20%) and day 30 (ejection fraction, 30% vs 23%). Confirmation of human MAPC marker vimentin in immunohistochemistry demonstrated that human MAPC integrated in the peri-infarct region. The proliferation marker Ki67 was absent in immunohistochemistry and teratoma formation was not found, indicating no tumorous potential of transplanted human MAPCs in the tumor-sensitive SCID model.
Conclusions
Transplantation of human MAPCs after MI ameliorates myocardial function, which may be explained by trophic effects of human MAPCs. Lack of evidence of tumorous potential in the tumor-sensitive SCID model indicates that human MAPCs may deliver an effective and safe stem cell pool for potential treatment of ischemic heart disease.
aDepartment of General and Vascular Surgery, Klinikum Grosshadern, Ludwig-Maximilians-University, Munich, Germany
bWalter Brendel Centre of Experimental Medicine, Ludwig-Maximilians-University, Munich, Germany
cMedical Clinic I, Department of Cardiology, Klinikum Grosshadern, Ludwig-Maximilians-University, Munich, Germany
dDepartment of Pharmacy, Pharmaceutical Biology, Ludwig-Maximilians-University, Munich, Germany
eMax Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
fInstitute of Pathology, Ludwig-Maximilians-University, Munich, Germany
Offprint requests to: Wolfgang M. Franz, Ph.D., Medizinische Klinik und Poliklinik I der LMU, Klinikum der Universität München-Großhadern, Marchioninistr. 15, D-81377 München
∗ Drs. Dimomeletis and Deindl contributed equally to this work.
ABSTRACT