Dr. Yelbuz and Mrs. Waldo contributed equally to this work.
Myocardial volume and organization are changed by failure of addition of secondary heart field myocardium to the cardiac outflow tract
Article first published online: 25 AUG 2003
Copyright © 2003 Wiley-Liss, Inc.
Volume 228, Issue 2, pages 152–160, October 2003
How to Cite
Yelbuz, T. M., Waldo, K. L., Zhang, X., Zdanowicz, M., Parker, J., Creazzo, T. L., Johnson, G. A. and Kirby, M. L. (2003), Myocardial volume and organization are changed by failure of addition of secondary heart field myocardium to the cardiac outflow tract. Dev. Dyn., 228: 152–160. doi: 10.1002/dvdy.10364
- Issue published online: 16 SEP 2003
- Article first published online: 25 AUG 2003
- Manuscript Accepted: 6 JUN 2003
- Manuscript Received: 21 APR 2003
- NIH. Grant Numbers: HL36059, HD17063, HD39946, P41-05959
- German Heart Foundation, German Research Council
- American Heart Association, Georgia Affiliate
- neural crest ablation;
- secondary heart field;
- myocardial volume
Cardiac neural crest ablation results in primary myocardial dysfunction and failure of the secondary heart field to add the definitive myocardium to the cardiac outflow tract. The current study was undertaken to understand the changes in myocardial characteristics in the heart tube, including volume, proliferation, and cell size when the myocardium from the secondary heart field fails to be added to the primary heart tube. We used magnetic resonance and confocal microscopy to determine that the volume of myocardium in the looped heart was dramatically reduced and the compact layer of myocardium was thinner after neural crest ablation, especially in the outflow tract and ventricular regions. Proliferation measured by 5-bromo-2′-deoxyuridine incorporation was elevated at only one stage during looping, cell death was normal and myocardial cell size was increased. Taken together, these results indicate that there are fewer myocytes in the heart. By incubation day 8 when the heart would have normally completed septation, the anterior (ventral) wall of the right ventricle and right ventricular outflow tract was significantly thinner in the neural crest-ablated embryos than normal, but the thickness of the compact myocardium was normal in all other regions of the heart. The decreased volume and number of myocardial cells in the heart tube after neural crest ablation most likely reflects the amount of myocardium added by the secondary heart field. Development Dynamics 228:152–160, 2003. © 2003 Wiley-Liss, Inc.