Neutralizing VEGF decreases tortuosity and alters endothelial cell division orientation in arterioles and veins in a rat model of ROP: relevance to plus disease.
OBJECTIVE
To study the effects of vascular endothelial growth factor (VEGF) on endothelial nitric oxide synthetase (eNOS) and retinal vascular tortuosity and cleavage planes in a rat model of retinopathy of prematurity (ROP).


METHODS
Within 4 hours of birth, pups and mothers were cycled between 50% and 10% oxygen daily. At postnatal day (p)12, pups received either intravitreous anti-rat neutralizing antibody to VEGF or control nonimmune rat IgG in one eye and returned to oxygen cycling until p14 when they were placed in room air (RA) for 4 days (50/10 oxygen-induced retinopathy [50/10 OIR]). Tortuosity indices and endothelial cleavage plane angles relative to the long axes of the major retinal vessels during anaphase were calculated from phosphohistone- and Alexa-isolectin-stained retinal flatmounts. Some retinas were processed for eNOS protein or phosphorylated/total eNOS.


RESULTS
Retinas from 50/10 OIR had increased tortuosity over time with peaks at p12 and p14 (P < 0.001 vs. RA) before the development of intravitreous neovascularization, which peaked at p18. Compared with RA, eNOS/actin in 50/10 OIR retinas was increased at p12 (P = 0.0003) and p14 (P = 0.047). Inhibition of VEGF with a neutralizing antibody decreased tortuosity and caused endothelial mitosis cleavage planes to orient in favor of vessel elongation but did not affect eNOS protein or activation.


CONCLUSIONS
In the 50/10 OIR model, a model with relevance to ROP, arteriolar tortuosity, and venous dilation are increased through VEGF, which influences the orientation of endothelial cell cleavage in major arterioles and veins, independent of eNOS.
Hartnett
M Elizabeth
ME
Department of Ophthalmology, The University of North Carolina, Chapel Hill, North Carolina, USA. hartnet@med.unc.edu
Martiniuk
David
D
Byfield
Grace
G
Geisen
Pete
P
Zeng
Gefei
G
Bautch
Victoria L
VL
D000818:Animals; D000831:Animals, Newborn; D000906:Antibodies / Q000494:pharmacology; D001160:Arterioles / Q000473:pathology; D002455:Cell Division / Q000187:drug effects; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000473:pathology*; D006801:Humans; D007231:Infant, Newborn; D008938:Mitosis / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D012169:Retinal Vein / Q000473:pathology; D012171:Retinal Vessels / Q000473:pathology* / Q000503:physiopathology; D012178:Retinopathy of Prematurity / Q000378:metabolism* / Q000473:pathology* / Q000503:physiopathology; D042461:Vascular Endothelial Growth Factor A / Q000276:immunology / Q000378:metabolism*; D014664:Vasodilation
D000906:Antibodies; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A