A caudal proliferating growth center contributes to both poles of the forming heart tube.
A caudal proliferating growth center contributes to both poles of the forming heart tube.
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DOI：
10.1161/circresaha.108.185843
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发表时间：
2009-01-30
影响因子：
20.1
通讯作者：
Moorman AF
中科院分区：
文献类型：
--
作者：
van den Berg G;Abu-Issa R;de Boer BA;Hutson MR;de Boer PA;Soufan AT;Ruijter JM;Kirby ML;van den Hoff MJ;Moorman AF
Recent studies have shown that the primary heart tube continues to grow by addition of cells from the coelomic wall. This growth occurs concomitantly with embryonic folding and formation of the coelomic cavity, making early heart formation morphologically complex. A scarcity of data on localized growth parameters further hampers the understanding of cardiac growth. Therefore, we investigated local proliferation during early heart formation. Firstly, we determined the cell-cycle length of primary myocardium of the early heart tube to be 5.5 days, showing that this myocardium is non-proliferating and implying that initial heart formation occurs solely by addition of cells. In line with this, we show that the heart tube rapidly lengthens at its inflow by differentiation of recently divided precursor-cells. To track the origin of these cells, we made quantitative 3D-reconstructions of proliferation in the forming heart tube and the mesoderm of its flanking coelomic walls. These reconstructions show a single, albeit bilateral, center of rapid proliferation in the caudo-medial pericardial back-wall. This center expresses Islet1. Cell tracing showed that cells from this caudal growth-center, besides feeding into the venous pole of the heart, also move cranially via the dorsal pericardial mesoderm and differentiate into myocardium at the arterial pole. Inhibition of caudal proliferation impairs the formation of both the atria and the right ventricle. These data show how a proliferating growth-center in the caudal coelomic wall elongates the heart tube at both its venous and arterial pole, providing a morphological mechanism for early heart formation.
