Role of vascular endothelial growth factor and placental growth factors during retinal vascular development and hyaloid regression.
OBJECTIVE
Vascular endothelial growth factor (VEGF)-A and placental growth factor (PlGF) are members of a large group of homologous peptides identified as the VEGF family. Although VEGF-A is known to act as a potent angiogenic peptide in the retina, the vasoactive function of PlGF in this tissue is less well defined. This study has sought to elucidate the expression patterns and modulatory role of these growth factors during retinal vascular development and hyaloid regression in the neonatal mouse.


METHODS
C57BL6J mice were killed at postnatal days (P)1, P3, P5, P7, P9, and P11. The eyes were enucleated and processed for in situ hybridization and immunocytochemistry and the retinas extracted for total protein or RNA. Separate groups of neonatal mice were also injected intraperitoneally daily from P2 through P9 with either VEGF-neutralizing antibody, PlGF-neutralizing antibody, isotype immunoglobulin (Ig)-G, or phosphate-buffered saline (PBS). The mice were then perfused with fluorescein isothiocyanate (FITC)-dextran, and the eyes were subsequently embedded in paraffin wax or flat mounted.


RESULTS
Quantitative (real-time) reverse transcription-polymerase chain reaction (RT-PCR) demonstrated similar expression patterns of VEGF-A and PlGF mRNA during neonatal retinal development, although the fluctuation between time periods was greater overall for VEGF-A. The localization of VEGF-A and PlGF in the retina, as revealed by in situ hybridization and immunohistochemistry, was also similar. Neutralization of VEGF-A caused a significant reduction in the hyaloid and retinal vasculature, whereas PlGF antibody treatment caused a marked persistence of the hyaloid without significantly affecting retinal vascular development.


CONCLUSIONS
Although having similar expression patterns in the retina, these growth factors appear to have distinct modulatory influences during normal retinal vascular development and hyaloid regression.
Feeney
Susan A
SA
Department of Ophthalmology, The Queen's University of Belfast, The Royal Victoria Hospital, Belfast, Northern Ireland, United Kingdom.
Simpson
David A C
DA
Gardiner
Thomas A
TA
Boyle
Cliona
C
Jamison
Pamela
P
Stitt
Alan W
AW
D000818:Animals; D000831:Animals, Newborn; D016228:Endothelial Growth Factors / Q000235:genetics / Q000502:physiology*; D005451:Fluorescein Angiography; D019084:Fluorescent Antibody Technique, Indirect; D017403:In Situ Hybridization; D051379:Mice; D008810:Mice, Inbred C57BL; D018919:Neovascularization, Physiologic; D000072483:Placenta Growth Factor; D011257:Pregnancy Proteins / Q000235:genetics / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D012171:Retinal Vessels / Q000196:embryology / Q000254:growth & development* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D042461:Vascular Endothelial Growth Factor A; D014822:Vitreous Body / Q000098:blood supply*
D016228:Endothelial Growth Factors; C000608037:Pgf protein, mouse; D011257:Pregnancy Proteins; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; D000072483:Placenta Growth Factor