Purchase this article with an account.
Ester Reina-Torres, Joseph M Sherwood, W Daniel Stamer, Darryl R Overby; Role of Vascular Endothelial Growth Factor (VEGF) in the regulation of conventional outflow facility in mice. Invest. Ophthalmol. Vis. Sci. 2014;55(13):2909.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Vascular Endothelial Growth Factor (VEGF) regulates microvascular fluid transport, but the role of VEGF in aqueous humor outflow has not been extensively studied. Endothelial permeability is determined partly by the balance between VEGF165a and VEGF165b, splice variants that have opposing effects on VEGF receptor stimulation. This project aims to determine the effect of VEGF165a and VEGF165b on conventional outflow facility (C) in mice.
Enucleated eyes from 24 C57BL/6J mice (10-12 weeks old, male) were perfused ex vivo using a pumpless perfusion system optimized for mouse eyes. An inline flow sensor was used to measure the flow rate (Q) into the eye as IOP was varied in steps of 2.5 mmHg between 5 and 20mmHg using an adjustable height reservoir. C was calculated as the slope of the linear regression of Q versus IOP. Paired eyes were perfused with DBG (Dulbecco’s PBS + 5.5mM glucose and divalent cations) or DBG including VEGF165a (0.1, or 0.5 µg/ml) or VEGF165b (0.5µg/ml). Linear Mixed Model (SPSS, IBM) was used to estimate statistical significance.
VEGF165a dose-dependently increased C. In controls, the baseline C was 13.59±7.6 nL/min/mmHg (N=17 eyes). VEGF165a increased C by 37±21% at 0.1µg/mL (p=0.04, N=6) and by 58±23% at 0.5µg/mL (p=0.02, N=4). In contrast, VEGF165b decreased C by 62±38% (p<0.0005; N=5) at 0.5µg/mL.
VEGF splice variants have differential effects on conventional outflow in mice, with VEGF165a increasing C and VEGF165b decreasing C. The balance between VEGF165a and VEGF165b may thereby regulate trabecular outflow and may serve as a target for future glaucoma therapies. Patients on long-term anti-VEGF therapy may therefore experience compromised outflow function resulting from an imbalance in VEGF isoform levels in the trabecular meshwork.
This PDF is available to Subscribers Only