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Endocardial tip cells in the human embryo - facts and hypotheses.

Rusu MC, Poalelungi CV, Vrapciu AD, Nicolescu MI, Hostiuc S, Mogoanta L, Taranu T - PLoS ONE (2015)

Bottom Line: Subepicardial vessels were found branching into the outer ventricular myocardium, with a pattern of recruiting α-SMA+/desmin+ vascular smooth muscle cells and pericytes.Within the inner myocardium, we found endothelial networks rooted from endocardium, guided by filopodia-projecting CD31+/CD34+/CD105+/ vimentin+ endocardial tip cells.Nevertheless, endocardial tip cells were also found in cardiac cushions, but they were not related to cushion endothelial networks.

View Article: PubMed Central - PubMed

Affiliation: Division of Anatomy, Faculty of Dental Medicine, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania; MEDCENTER-Center of Excellence in Laboratory Medicine and Pathology, Bucharest, Romania.

ABSTRACT
Experimental studies regarding coronary embryogenesis suggest that the endocardium is a source of endothelial cells for the myocardial networks. As this was not previously documented in human embryos, we aimed to study whether or not endothelial tip cells could be correlated with endocardial-dependent mechanisms of sprouting angiogenesis. Six human embryos (43-56 days) were obtained and processed in accordance with ethical regulations; immunohistochemistry was performed for CD105 (endoglin), CD31, CD34, α-smooth muscle actin, desmin and vimentin antibodies. Primitive main vessels were found deriving from both the sinus venosus and aorta, and were sought to be the primordia of the venous and arterial ends of cardiac microcirculation. Subepicardial vessels were found branching into the outer ventricular myocardium, with a pattern of recruiting α-SMA+/desmin+ vascular smooth muscle cells and pericytes. Endothelial sprouts were guided by CD31+/CD34+/CD105+/vimentin+ endothelial tip cells. Within the inner myocardium, we found endothelial networks rooted from endocardium, guided by filopodia-projecting CD31+/CD34+/CD105+/ vimentin+ endocardial tip cells. The myocardial microcirculatory bed in the atria was mostly originated from endocardium, as well. Nevertheless, endocardial tip cells were also found in cardiac cushions, but they were not related to cushion endothelial networks. A general anatomical pattern of cardiac microvascular embryogenesis was thus hypothesized; the arterial and venous ends being linked, respectively, to the aorta and sinus venosus. Further elongation of the vessels may be related to the epicardium and subepicardial stroma and the intramyocardial network, depending on either endothelial and endocardial filopodia-guided tip cells in ventricles, or mostly on endocardium, in atria.

No MeSH data available.


Related in: MedlinePlus

Human embryonic heart (56 days), CD 34 immune labeling.Immune labeling with CD34 antibodies of a 56 days human embryonic heart, oblique-sagittal cut. General view (A) with detailed area in (B), indicated by the black connector. The CD34 positive endocardial cells cover the ventricular cavity (*). Endocardial tip cells (white arrows) are identified projecting filopodia within the myocardium. The endocardially-derived endothelial networks advance towards the epicardially-derived endothelial networks. ac: apex cordis; P:pericardium.
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pone.0115853.g006: Human embryonic heart (56 days), CD 34 immune labeling.Immune labeling with CD34 antibodies of a 56 days human embryonic heart, oblique-sagittal cut. General view (A) with detailed area in (B), indicated by the black connector. The CD34 positive endocardial cells cover the ventricular cavity (*). Endocardial tip cells (white arrows) are identified projecting filopodia within the myocardium. The endocardially-derived endothelial networks advance towards the epicardially-derived endothelial networks. ac: apex cordis; P:pericardium.

Mentions: Within the ventricular walls the general pattern appeared as follows (Fig. 6): the outer myocardium was supplied by subepicardial vessels and the endothelial sprouts were guided by ETCs, while the inner myocardium was supplied by endocardial-derived endothelial networks, the endothelial sprouts being guided by endocardial tip cells. A different pattern was encountered in the atrioventricular and arterial cushions: these were seemingly completely devoid of microvessels but endocardial tip cells were consistently projecting filopodia in the subendocardial tissues (Fig. 7).


Endocardial tip cells in the human embryo - facts and hypotheses.

Rusu MC, Poalelungi CV, Vrapciu AD, Nicolescu MI, Hostiuc S, Mogoanta L, Taranu T - PLoS ONE (2015)

Human embryonic heart (56 days), CD 34 immune labeling.Immune labeling with CD34 antibodies of a 56 days human embryonic heart, oblique-sagittal cut. General view (A) with detailed area in (B), indicated by the black connector. The CD34 positive endocardial cells cover the ventricular cavity (*). Endocardial tip cells (white arrows) are identified projecting filopodia within the myocardium. The endocardially-derived endothelial networks advance towards the epicardially-derived endothelial networks. ac: apex cordis; P:pericardium.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4305311&req=5

pone.0115853.g006: Human embryonic heart (56 days), CD 34 immune labeling.Immune labeling with CD34 antibodies of a 56 days human embryonic heart, oblique-sagittal cut. General view (A) with detailed area in (B), indicated by the black connector. The CD34 positive endocardial cells cover the ventricular cavity (*). Endocardial tip cells (white arrows) are identified projecting filopodia within the myocardium. The endocardially-derived endothelial networks advance towards the epicardially-derived endothelial networks. ac: apex cordis; P:pericardium.
Mentions: Within the ventricular walls the general pattern appeared as follows (Fig. 6): the outer myocardium was supplied by subepicardial vessels and the endothelial sprouts were guided by ETCs, while the inner myocardium was supplied by endocardial-derived endothelial networks, the endothelial sprouts being guided by endocardial tip cells. A different pattern was encountered in the atrioventricular and arterial cushions: these were seemingly completely devoid of microvessels but endocardial tip cells were consistently projecting filopodia in the subendocardial tissues (Fig. 7).

Bottom Line: Subepicardial vessels were found branching into the outer ventricular myocardium, with a pattern of recruiting α-SMA+/desmin+ vascular smooth muscle cells and pericytes.Within the inner myocardium, we found endothelial networks rooted from endocardium, guided by filopodia-projecting CD31+/CD34+/CD105+/ vimentin+ endocardial tip cells.Nevertheless, endocardial tip cells were also found in cardiac cushions, but they were not related to cushion endothelial networks.

View Article: PubMed Central - PubMed

Affiliation: Division of Anatomy, Faculty of Dental Medicine, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania; MEDCENTER-Center of Excellence in Laboratory Medicine and Pathology, Bucharest, Romania.

ABSTRACT
Experimental studies regarding coronary embryogenesis suggest that the endocardium is a source of endothelial cells for the myocardial networks. As this was not previously documented in human embryos, we aimed to study whether or not endothelial tip cells could be correlated with endocardial-dependent mechanisms of sprouting angiogenesis. Six human embryos (43-56 days) were obtained and processed in accordance with ethical regulations; immunohistochemistry was performed for CD105 (endoglin), CD31, CD34, α-smooth muscle actin, desmin and vimentin antibodies. Primitive main vessels were found deriving from both the sinus venosus and aorta, and were sought to be the primordia of the venous and arterial ends of cardiac microcirculation. Subepicardial vessels were found branching into the outer ventricular myocardium, with a pattern of recruiting α-SMA+/desmin+ vascular smooth muscle cells and pericytes. Endothelial sprouts were guided by CD31+/CD34+/CD105+/vimentin+ endothelial tip cells. Within the inner myocardium, we found endothelial networks rooted from endocardium, guided by filopodia-projecting CD31+/CD34+/CD105+/ vimentin+ endocardial tip cells. The myocardial microcirculatory bed in the atria was mostly originated from endocardium, as well. Nevertheless, endocardial tip cells were also found in cardiac cushions, but they were not related to cushion endothelial networks. A general anatomical pattern of cardiac microvascular embryogenesis was thus hypothesized; the arterial and venous ends being linked, respectively, to the aorta and sinus venosus. Further elongation of the vessels may be related to the epicardium and subepicardial stroma and the intramyocardial network, depending on either endothelial and endocardial filopodia-guided tip cells in ventricles, or mostly on endocardium, in atria.

No MeSH data available.


Related in: MedlinePlus