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Three-dimensional Rendering and Analysis of Immunolabeled, Clarified Human Placental Villous Vascular Networks
Published on: March 29, 2018
Development of the human choriocapillaris
G A Lutty1, T Hasegawa, T Baba
1Department of Ophthalmology, Wilmer Ophthalmological Institute, Johns Hopkins Hospital, Baltimore, MD 21287-9115, USA. galutty@jhmi.edu
Eye (London, England)
|January 16, 2010
Summary
Human choroidal vascular development begins with haemo-vasculogenesis, involving blood vessel and cell formation from common precursors. Later fetal development utilizes angiogenesis for larger vessel growth, with mature structures forming around 22 weeks gestation.
Area of Science:
- Ophthalmology
- Developmental Biology
- Vascular Biology
Background:
- New blood vessel formation occurs via vasculogenesis and angiogenesis.
- Haemo-vasculogenesis, a third mechanism, involves common precursors forming both blood vessels and cells.
- Understanding human choroidal vascular development is crucial for ocular health.
Purpose of the Study:
- To describe the mechanisms of human choroidal vascular development from 6 to 22 weeks gestation.
- To identify the cellular markers and structural changes during choroidal vascularization.
- To differentiate between haemo-vasculogenesis and angiogenesis in the developing choroid.
Main Methods:
- Review of human choroidal vascular development from 6 to 22 weeks gestation.
- Analysis of endothelial cell (EC) and angioblast markers (CD31, CD34, CD39, VEGFR-2).
- Assessment of erythroblast markers (Hb-epsilon) and cell proliferation (Ki67).
- Transmission Electron Microscopy (TEM) for ultrastructural analysis (basement membrane, pericytes, fenestrations).
Main Results:
- EC and angioblast markers were present from 7 to 22 weeks gestation.
- Erythroblasts (Hb-epsilon(+)) expressing vascular markers were abundant from 6 to 8 weeks gestation.
- Angiogenesis (Ki67+) was observed starting at 12 weeks gestation.
- Immature choroidal capillaries (CC) lacked basement membranes and pericytes until late gestation.
- Mature fenestrations, pericytes, and basal lamina formed around 22 weeks gestation.
Conclusions:
- Embryonic choroidal capillaries initially form via haemo-vasculogenesis (Hb-epsilon(+)/CD31(+)).
- Angiogenesis (CD34(+)/Ki67(+)) is the primary mechanism for intermediate and large choroidal vessel development later in gestation.
- Choroidal vascular maturation, including fenestrations and pericytes, is completed around 22 weeks gestation, coinciding with photoreceptor development.
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