The embryonic human choriocapillaris develops by hemo-vasculogenesis.
The purpose of this study was to characterize normal human choroidal vascular development from 6-23 weeks gestation (WG). Markers of endothelial cells (EC) (CD34, CD31, vWf), angioblasts and EC (CD39), leukocytes (CD45), erythroblasts (epsilon chain of hemoglobin, Hb-e), proliferating cells (Ki67), and VEGFR-2 were employed. At 6-7 WG, many erythroblasts were observed within islands of precursor cells in the choriocapillaris layer and others were independent from the islands. Many erythroblasts (Hb-epsilon(+)) were also positive for EC markers and/or VEGFR-2. By 8-12 WG, most of the Hb-epsilon cells had disappeared and vascular lumens became apparent. At 14-23 WG, some EC were proliferating on the scleral side of choriocapillaris in association with forming deeper vessels. In conclusion, embryonic choriocapillaris appears to form initially by hemo-vasculogenesis (blood vessels and blood cells form simultaneously from common precursors) while angiogenesis appears to be the mode of intermediate and large choroidal vessel development in the fetus.
Hasegawa
Takuya
T
Wilmer Ophthalmological Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
McLeod
D Scott
DS
Bhutto
Imran A
IA
Prow
Tarl
T
Merges
Carol A
CA
Grebe
Rhonda
R
Lutty
Gerard A
GA
D002829:Choroid / Q000098:blood supply* / Q000196:embryology / Q000254:growth & development; D004095:Dihydropyridines; D006801:Humans; D018919:Neovascularization, Physiologic / Q000502:physiology*
D004095:Dihydropyridines; C082341:F 0401