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Journal ArticleDOI

Retinal angiogenesis in the human embryo.

01 May 1970-British Medical Bulletin (Br Med Bull)-Vol. 26, Iss: 2, pp 103-106
About: This article is published in British Medical Bulletin.The article was published on 1970-05-01. It has received 174 citations till now. The article focuses on the topics: Embryo & Angiogenesis.
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Journal ArticleDOI
TL;DR: The roles played by VEGF in the pathogenesis of retinopathy of prematurity, diabetic Retinopathy and age-related macular degeneration are described and the potential disadvantages of inhibiting VEGf will be discussed, as will the rationales for targeting other V EGF-related modulators of angiogenesis.

611 citations


Cites background from "Retinal angiogenesis in the human e..."

  • ...Several studies have also examined the process in the human fetal retina (Michaelson, 1948; Nilausen, 1958; Cogan, 1963; Ashton, 1970; Nishimura and Taniguchi, 1982; Penfold et al., 1990; Gariano et al., 1994; Hughes et al., 2000)....

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  • ...The process of normal vascularization has been extensively examined in the kitten, mouse and rat retinas (Ashton et al., 1957; Ashton, 1961; Ashton, 1970; Blanks and Johnson, 1983; Connolly et al., 1988; Chan-Ling et al., 1990; Smith et al., 1994; Stone et al., 1995; Dorrell and Friedlander, 2006)....

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  • ...…blood vessels from mesodermal precursor cells (angioblasts), and angiogenesis, sprouting of new vessels from existing blood vessels (Ashton, 1966; Ashton, 1970; Flower et al., 1985; McLeod et al., 1987; Kretzer and Hittner, 1988; Chan-Ling et al., 1990; Jiang et al., 1995; Risau and Flamme,…...

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  • ...For example, in humans the process occurs primarily during the latter half of gestation, whereas in rodents the process is completed in the first two weeks after birth (Michaelson et al., 1954; Ashton, 1970; Stone et al., 1995; Engerman and Meyer, 1965)....

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  • ...Studies indicate that development of the retinal vasculature may occur by both vasculogenesis, de novo formation of blood vessels from mesodermal precursor cells (angioblasts), and angiogenesis, sprouting of new vessels from existing blood vessels (Ashton, 1966; Ashton, 1970; Flower et al., 1985; McLeod et al., 1987; Kretzer and Hittner, 1988; Chan-Ling et al., 1990; Jiang et al., 1995; Risau and Flamme, 1995; Risau, 1997; Hughes et al., 2000)....

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Journal ArticleDOI
TL;DR: The cellular and physiological mechanisms responsible for the regulation of blood flow in the retina and choroid in health and disease are reviewed and the role of capillaries, astrocytes and pericytes in regulating blood flow is discussed.

513 citations


Cites background from "Retinal angiogenesis in the human e..."

  • ...In humans, the first retinal vessels form at the optic disc at approximately 14 weeks gestation (Ashton, 1970; Hughes et al., 2000), whereas primitive endothelium-lined elements e giving rise to choroidal vessels, are present as early as 29 days gestation (Ozanics et al., 1978) and an extensive…...

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  • ...In humans, the first retinal vessels form at the optic disc at approximately 14 weeks gestation (Ashton, 1970; Hughes et al., 2000), whereas primitive...

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Journal ArticleDOI
TL;DR: Improved understanding of the molecular mechanisms controlling retinal blood vessel behaviour both during development and under pathological conditions will provide the basis of future therapeutic approaches aimed at manipulating retinalBlood vessels.
Abstract: Blood vessels that supply the inner portion of the retina are extensively reorganized during development. The vessel regression, sprouting angiogenesis, vascular remodelling and vessel differentiation events involved critically depend on cell-cell signalling between different cellular components such as neurons, glia, endothelial cells, pericytes and immune cells. Studies in mice using transgenic and gene deletion approaches have started to unravel the genetic basis of some of these signalling pathways and have lead to a much improved understanding of the molecular mechanisms controlling retinal blood vessel behaviour both during development and under pathological conditions. Such insight will provide the basis of future therapeutic approaches aimed at manipulating retinal blood vessels.

454 citations

Journal ArticleDOI
Jan Provis1
TL;DR: In human and macaque retina, different mechanisms appear to govern the development of the retinal vessels growing along the horizontal meridian of the retina towards the central area, which contains the fovea, and observations suggest that molecular markers define thefoveal region and inhibit cell proliferation and vascular growth at the fvea.

345 citations

Journal Article
TL;DR: Observed mechanisms of retinal vascularization appear similar to those of vascularization of the central nervous system during development, and suggest that the formation of primordial vessels in the central retina is mediated by vasculogenesis, whereas angiogenesis is responsible for increasing vascular density and peripheral vascularization in the inner retina.
Abstract: Purpose To characterize the topography of and the cellular processes that underlie vascularization of the human retina. Methods The vasculature of human eyes obtained from fetuses ranging in age from 14 to 38 weeks of gestation (WG) was examined in Nissl-stained, whole-mount preparations and by anti-CD34 immunohistochemistry. Results The first event in retinal vascularization, apparent before 15 WG, was the migration of large numbers of spindle-shaped mesenchymal precursor cells from the optic disc. These cells proliferated and differentiated to produce cords of endothelial cells. By 15 WG, some cords were already patent and formed an immature vascular tree in the inner retinal layers that was centered on the optic disc. These processes are consistent with vessel formation by vasculogenesis. Angiogenesis then increased the vascular density of this immature plexus and extended it peripherally and temporally. Maturation of the plexus was characterized by substantial remodeling, which involved the withdrawal of endothelial cells into neighboring vascular segments. The outer plexus was formed as a result of the extension of capillary-sized buds from the existing inner vessels, a process that began around the incipient fovea between 25 and 26 WG. Conclusions These observations suggest that the formation of primordial vessels in the central retina is mediated by vasculogenesis, whereas angiogenesis is responsible for increasing vascular density and peripheral vascularization in the inner retina. In contrast, the outer plexus and the radial peripapillary capillaries are formed by angiogenesis only. These mechanisms of retinal vascularization appear similar to those of vascularization of the central nervous system during development.

296 citations