Angioblasts initially form small cell clusters (blood islands) within the embryonic and extraembryonic mesoderm. These blood islands extend and fuse together making a primordial vascular network. Within these islands the peripheral cells form endothelial cells while the core cells form blood cells (haemocytoblasts).
Fetal blood vessel
Recent work has shown that the formation of the initial endothelial tube is by a process of coalescence of cellular vacuoles within the developing endothelial cells, which fuse together without cytoplasmic mixing to form the blood vessel lumen.
Blood Vessel Formation
(Image: Developmental biology: The hole picture Keith Mostov and Fernando Martin-Belmonte Nature 442, 363-364 27 July 2006)
Page Links: Introduction | Some Recent Findings | Endothelial Tube Formation | Endothelial Progenitors | Stimulators of Angiogenisis | Inhibitors of Angiogenisis | Vascular Endothelial Growth Factor | Cardiac Blood Vessels | References | Glossary
Wasteson P, Johansson BR, Jukkola T, Breuer S, Akyürek LM, Partanen J, Lindahl P. Developmental origin of smooth muscle cells in the descending aorta in mice. Development. 2008 May;135(10):1823-32. (More? Musculoskeletal Development - Mesoderm/Somite)
"Aortic smooth muscle cells (SMCs) have been proposed to derive from lateral plate mesoderm. ....(these results) suggested that all SMCs in the adult descending aorta derive from the somites, whereas no contribution was recorded from lateral plate mesoderm."
High FA, Lu MM, Pear WS, Loomes KM, Kaestner KH, Epstein JA. Endothelial expression of the Notch ligand Jagged1 is required for vascular smooth muscle development. Proc Natl Acad Sci U S A. 2008 Feb 1;
"The Notch ligand Jagged1 (Jag1) is essential for vascular remodeling. ...Jag1 null phenotype. These embryos show striking deficits in vascular smooth muscle, whereas endothelial Notch activation and arterial-venous differentiation appear normal."
Hellstrom M, Phng LK, Hofmann JJ, Wallgard E, Coultas L, Lindblom P, Alva J, Nilsson AK, Karlsson L, Gaiano N, Yoon K, Rossant J, Iruela-Arispe ML, Kalen M, Gerhardt H, Betsholtz C. Dll4 signalling through Notch1 regulates formation of tip cells during angiogenesis. Nature. 2007 Feb 15;445(7129):776-80.
"In sprouting angiogenesis, specialized endothelial tip cells lead the outgrowth of blood-vessel sprouts towards gradients of vascular endothelial growth factor (VEGF)-A. ...suggest that Dll4-Notch1 signalling between the endothelial cells within the angiogenic sprout serves to restrict tip-cell formation in response to VEGF, thereby establishing the adequate ratio between tip and stalk cells required for correct sprouting and branching patterns."
Kamei M, Saunders WB, Bayless KJ, Dye L, Davis GE, Weinstein BM. Endothelial tubes assemble from intracellular vacuoles in vivo. Nature. 2006 Jul 27;442(7101):453-6.
"More than 25 years ago, in some of the first endothelial cell culture experiments in vitro, Folkman and Haudenschild described "longitudinal vacuoles" that "appeared to be extruded and connected from one cell to the next" "...Here we use high-resolution time-lapse two-photon imaging of transgenic zebrafish to examine how endothelial tubes assemble in vivo, comparing our results with time-lapse imaging of human endothelial-cell tube formation in three-dimensional collagen matrices in vitro. Our results provide strong support for a model in which the formation and intracellular and intercellular fusion of endothelial vacuoles drives vascular lumen formation."
Furuta C, Ema H, Takayanagi S, Ogaeri T, Okamura D, Matsui Y, Nakauchi H. Discordant developmental waves of angioblasts and hemangioblasts in the early gastrulating mouse embryo. Development. 2006 Jul;133(14):2771-9.
Recent work has shown that the formation of the initial endothelial tube is by a process of coalescence of cellular vacuoles within the developing endothelial cells, which fuse together without cytoplasmic mixing to form the blood vessel lumen.
Reyes M, Dudek A, Jahagirdar B, Koodie L, Marker PH, Verfaillie CM. Origin of endothelial progenitors in human postnatal bone marrow. J Clin Invest. 2002 Feb;109(3):337-46.
Blood Vessel Formation
(Image: Developmental biology: The hole picture Keith Mostov and Fernando Martin-Belmonte Nature 442, 363-364 27 July 2006)
Kamei M, Saunders WB, Bayless KJ, Dye L, Davis GE, Weinstein BM. Endothelial tubes assemble from intracellular vacuoles in vivo. Nature. 2006 Jul 27;442(7101):453-6.
Berthod F, Germain L, Tremblay N, Auger FA. Extracellular matrix deposition by fibroblasts is necessary to promote capillary-like tube formation in vitro. J Cell Physiol. 2006 May;207(2):491-8.
Davis GE, Bayless KJ.. An integrin and Rho GTPase-dependent pinocytic vacuole mechanism controls capillary lumen formation in collagen and fibrin matrices. Microcirculation. 2003 Jan;10(1):27-44.
Yang S, Graham J, Kahn JW, Schwartz EA, Gerritsen ME. Functional roles for PECAM-1 (CD31) and VE-cadherin (CD144) in tube assembly and lumen formation in three-dimensional collagen gels. Am J Pathol. 1999 Sep;155(3):887-95.
Folkman J, Haudenschild C. Angiogenesis in vitro. Nature. 1980 Dec 11;288(5791):551-6.
(data from table 1 Vascular morphogenesis in the ovary, Augustin H.G Bailliere's Clinical Obstetrics and Gynaecology 14:867-882, 2000)
(data from table 1 Vascular morphogenesis in the ovary, Augustin H.G Bailliere's Clinical Obstetrics and Gynaecology 14:867-882, 2000)
Growing blood vessels follow a gradient generated by tagret tissues/regions of Vascular Endothelial Growth Factor (VEGF) to establish a vascular bed. Recent findings suggest that Notch signaling acts as an inhibitor for this system, preventing sprouting of blood vessels.
Notch is a transmembrane receptor protein involved in regulating cell differentiation in many developing systems.
Links: OMIM - VEGFA | OMIM - Notch
Earliest vessels in the heart wall develop subepicardially (beneath the outside surface of the heart) near the apex at Carnegie stage 15, which then extends centripetally and at stage 17 coronary arterial stems communicate with the aortic lumen.
(Text modified from: Turner K, Navaratnam V. The positions of coronary arterial ostia. Clin Anat. 1996;9(6):376-80.)
Click on the listed keywords below (used to search the external database) the most current references on Medline will be displayed.
A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Numbers | Old Glossary
Page 2 | Abnormalities
| OMIM
| Questions
| Medline
Page
3 | Pig
Stage 13/14
Page
4 | Human
(Stage22) | Selected
Human highpower
Molecular
| Blood
| Text only
page | WWW Links
Heart Movies
Postnatal
Home Page
Embryo stages
Fetal Dev
System Notes
Animal Dev
Acknowledgements
Introduction
Abnormalities
Stage 13/14
Stage 22
Stage 22 Selected Highpower
Heart
Heart Rate
Blood
Blood Vessels
Molecular
Lymphatic
Text only page
WWW Links
Heart Movies
Postnatal
Movies
Audio
Class Notes
Serial Images
K12 Students
Abnormal
Prenatal Diagnosis
Animal Embryos
Mechanisms
Molecular
Histology
Statistics
History
Site Map
Glossary
OMIM
School of Med Sci
UNSW Medicine
University of NSW
UNSW Cell Biology
NCBI Books
New 2010 Site
Enjoyed this site? Visit the New 2010 Site!
Blood develops initially within the core of "blood islands" in the mesoderm.
During development, there follows a series of "relocations" of the stem cells to different organs within the embryo.
In the adult, these stem cells are located in the bone marrow. At the time when blood first forms, there are no bones!
These Notes are currently being updated for Version 4.0
Please email Dr Mark Hill if you wish to make a comment about this current project.