Lineage tracing of cardiac explant derived cells.
OBJECTIVE
Cultured cardiac explants produce a heterogeneous population of cells including a distinctive population of refractile cells described here as small round cardiac explant derived cells (EDCs). The aim of this study was to explore the source, morphology and cardiogenic potential of EDCs.


METHODS
Transgenic MLC2v-Cre/ZEG, and actin-eGFP mice were used for lineage-tracing of EDCs in vitro and in vivo. C57B16 mice were used as cell transplant recipients of EDCs from transgenic hearts, as well as for the general characterisation of EDCs. The activation of cardiac-specific markers were analysed by: immunohistochemistry with bright field and immunofluorescent microscopy, electron microscopy, PCR and RT-PCR. Functional engraftment of transplanted cells was further investigated with calcium transient studies.


RESULTS
Production of EDCs was highly dependent on the retention of blood-derived cells or factors in the cultured explants. These cells shared some characteristics of cardiac myocytes in vitro and survived engraftment in the adult heart in vivo. However, EDCs failed to differentiate into functional cardiac myocytes in vivo as demonstrated by the absence of stimulation-evoked intracellular calcium transients following transplantation into the peri-infarct zone.


CONCLUSIONS
This study highlights that positive identification based upon one parameter alone such as morphology or immunofluorescene is not adequate to identify the source, fate and function of adult cardiac explant derived cells.
Shenje
Lincoln T
LT
Cardiac Surgery Unit, Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom.
Field
Loren J
LJ
Pritchard
Catrin A
CA
Guerin
Christopher J
CJ
Rubart
Michael
M
Soonpaa
Mark H
MH
Ang
Keng-Leong
KL
Galiñanes
Manuel
M
D000818:Animals; D002118:Calcium / Q000378:metabolism; D019070:Cell Lineage; D002478:Cells, Cultured; D006321:Heart / Q000033:anatomy & histology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D009206:Myocardium / Q000166:cytology*; D032383:Myocytes, Cardiac / Q000166:cytology*; D010477:Perfusion; D016133:Polymerase Chain Reaction; D019076:Transgenes
D002118:Calcium