Published Online
on March 6, 2006

A more recent version of this article appeared on March 14, 2006

This Article Full Text (PDF) Data Supplement All Versions of this Article: 113/10/1326    most recent CIRCULATIONAHA.105.559005v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Gruh, I. Articles by Martin, U. Search for Related Content PubMed PubMed Citation Articles by Gruh, I. Articles by Martin, U. Pubmed/NCBI databases Medline Plus Health Information Stem Cells Related Collections Cell biology/structural biology

Submitted on April 28, 2005
Revised on December 21, 2005
Accepted on December 23, 2005

No Evidence of Transdifferentiation of Human Endothelial Progenitor Cells Into Cardiomyocytes After Coculture With Neonatal Rat Cardiomyocytes

Ina Gruh PhD, Janina Beilner , Ulrike Blomer MD, PhD, Andreas Schmiedl PhD, Ingrid Schmidt-Richter , Marie-Luise Kruse PhD, Axel Haverich MD, and Ulrich Martin PhD^*

From the Leibniz Research Laboratories for Biotechnology and Artificial Organs (I.G., J.B., U.B., I.S.-R., A.H., U.M.) and Department of Functional and Applied Anatomy (A.S.), Hannover Medical School, Hannover; and Laboratory for Molecular Gastroenterology and Hepatology, Clinic for Internal Medicine, University of Kiel, Kiel (M.K.), Germany.

^* To whom correspondence should be addressed. E-mail: martin.ulrich{at}mh-hannover.de.

Background--Recent studies have suggested the differentiation of human endothelial progenitor cells (huEPCs) isolated from peripheral blood into cardiomyocytes. This study investigates whether, when cocultured, neonatal rat cardiomyocytes (NRCMs) can induce transdifferentiation of huEPCs into cardiomyocytes.

Methods and Results--Coculture experiments with 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine (DiI)-labeled huEPCs and NRCMs have been performed. Cocultures have been analyzed by means of flow cytometry, 3D confocal laser microscopy, species-specific reverse transcriptase-polymerase chain reaction for the expression of human cardiac marker genes, and electron microscopy. Although fluorescence-activated cell sorting (FACS) analysis and conventional wide-field fluorescence microscopy suggested the existence of DiI^pos cardiomyocytes in cocultures, no convincing evidence of cardiac differentiation of huEPCs has been obtained. Apparently, DiI^pos cardiomyocytes were identified as necrotic NRCMs or NRCM-derived vesicles with high levels of autofluorescence or, alternatively, as NRCMs lying on top of or below labeled huEPCs or huEPC fragments. Accordingly, no expression of human Nkx2.5, GATA-4, or cardiac troponin I was detected.

Conclusions--No convincing evidence of transdifferentiation of huEPCs into cardiomyocytes was obtained. Although we cannot exclude that recent contrary data may be due to slightly different culture protocols, our study has revealed that recently applied standard analysis tools including FACS and wide-field fluorescence microscopy are not sufficient to demonstrate transdifferentiation in coculture settings and can lead to misinterpretation of the data obtained solely with these methods.

Key words: cells • differentiation • endothelium • myocytes

This article has been cited by other articles:

				N. Derval, L. Barandon, P. Dufourcq, L. Leroux, J.-M. D. Lamaziere, D. Daret, T. Couffinhal, and C. Duplaa Epicardial deposition of endothelial progenitor and mesenchymal stem cells in a coated muscle patch after myocardial infarction in a murine model. Eur. J. Cardiothorac. Surg., August 1, 2008; 34(2): 248 - 254. [Abstract] [Full Text] [PDF]

				C. Mauritz, K. Schwanke, M. Reppel, S. Neef, K. Katsirntaki, L. S. Maier, F. Nguemo, S. Menke, M. Haustein, J. Hescheler, et al. Generation of Functional Murine Cardiac Myocytes From Induced Pluripotent Stem Cells Circulation, July 29, 2008; 118(5): 507 - 517. [Abstract] [Full Text] [PDF]

				S. Rupp, M. Koyanagi, M. Iwasaki, F. Diehl, P. Bushoven, D. Schranz, A. M. Zeiher, and S. Dimmeler Genetic proof-of-concept for cardiac gene expression in human circulating blood-derived progenitor cells. J. Am. Coll. Cardiol., June 10, 2008; 51(23): 2289 - 2290. [Full Text] [PDF]

				K. V Arom, P. Ruengsakulrach, and V. Jotisakulratana Intramyocardial Angiogenic Cell Precursor Injection for Cardiomyopathy Asian Cardiovasc Thorac Ann, April 1, 2008; 16(2): 143 - 148. [Abstract] [Full Text] [PDF]

				A. Orlandi, F. Pagani, D. Avitabile, G. Bonanno, G. Scambia, E. Vigna, F. Grassi, F. Eusebi, S. Fucile, M. Pesce, et al. Functional properties of cells obtained from human cord blood CD34+ stem cells and mouse cardiac myocytes in coculture Am J Physiol Heart Circ Physiol, April 1, 2008; 294(4): H1541 - H1549. [Abstract] [Full Text] [PDF]

				S. Burghoff, Z. Ding, S. Godecke, A. Assmann, A. Wirrwar, D. Buchholz, O. Sergeeva, C. Leurs, H. Hanenberg, H.-W. Muller, et al. Horizontal gene transfer from human endothelial cells to rat cardiomyocytes after intracoronary transplantation Cardiovasc Res, February 1, 2008; 77(3): 534 - 543. [Abstract] [Full Text] [PDF]

				K. Guan, S. Wagner, B. Unsold, L. S. Maier, D. Kaiser, B. Hemmerlein, K. Nayernia, W. Engel, and G. Hasenfuss Generation of Functional Cardiomyocytes From Adult Mouse Spermatogonial Stem Cells Circ. Res., June 8, 2007; 100(11): 1615 - 1625. [Abstract] [Full Text] [PDF]

				P. Menasche You Can't Judge a Book by Its Cover Circulation, March 14, 2006; 113(10): 1275 - 1277. [Full Text] [PDF]