June 2017
Volume 58, Issue 8
Open Access
ARVO Annual Meeting Abstract  |   June 2017
VEGF Causes Retinal Nonperfusion by Leukostasis Stimulated by VEGFR1-mediated Leukocyte Recruitment and VCAM-1-mediated Leukocyte Adhesion
Author Affiliations & Notes
  • yuanyuan liu
    ophthalmology, Johns Hopkins University, Baltimore, Maryland, United States
    Ophthalmology, Tianjin Medical University, Tianjin, China
  • Ji-kui Shen
    ophthalmology, Johns Hopkins University, Baltimore, Maryland, United States
  • Seth Daniel Fortmann
    ophthalmology, Johns Hopkins University, Baltimore, Maryland, United States
  • Peter A Campochiaro
    ophthalmology, Johns Hopkins University, Baltimore, Maryland, United States
  • Footnotes
    Commercial Relationships   yuanyuan liu, None; Ji-kui Shen, None; Seth Fortmann, None; Peter Campochiaro, None
  • Footnotes
    Support  None
Investigative Ophthalmology & Visual Science June 2017, Vol.58, 1539. doi:
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      yuanyuan liu, Ji-kui Shen, Seth Daniel Fortmann, Peter A Campochiaro; VEGF Causes Retinal Nonperfusion by Leukostasis Stimulated by VEGFR1-mediated Leukocyte Recruitment and VCAM-1-mediated Leukocyte Adhesion. Invest. Ophthalmol. Vis. Sci. 2017;58(8):1539.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose : High levels of VEGF promote retinal nonperfusion in diabetic retinopathy and retinal vein occlusion. We sought to test that VEGF-induced retinal nonperfusion is caused by leukostasis and investigate molecular mechanisms.

Methods : At various time points after intravitreous injection of VEGF165 in C57BL/6 mice or administration of doxycycline to Tet/opsin/VEGFdouble transgenic mice or rho/VEGF transgenic mice, leukostasis was quantified by counting intravascular adherent concanavalin A (conA)-stained leukocytes in retinal flat mounts, nonperfusion was measured by fluorescein angiography (FA),FITC-labeled dextran perfusion and hypoxyprobe staining,adhesion molecule expression was measured by qRT-PCR and immunofluorescence , and leukocytes subtypes were distinguished by F4/80, Ly6G staining.The role of VEGFR1 and VCAM1 was tested by intravenous injection of anti-VEGFR1 or anti-VCAM1 in VEGF-injected mice or in doxycycline-treated Tet/opsin mice.

Results : Intravitreous injection of VEGF or sustained expression of VEGF in photoreceptors caused dose-dependent leukostasis, in which both monocytes and neutrophils participate, that peaked 1 day after VEGF injection and 3 days after onset of sustained VEGF expression when mRNA levels for VCAM-1 and α4, β1 integrin subunitswere significantly increased. The leukostasiscaused retinal vessel occlusion and nonperfusedareas visualized by FA, dextranand hypoxyprobe staining in Tet/opsin mice and Rho/VEGF mice.Leukostasis and nonperfusion were eliminated by cessation of doxycycline in Tet/opsin mice. Immunofluorescent staining for VCAM-1 was not seen in retinal vessels of untreated mice and was present 1 day after VEGF injection.Intravenous injection of anti-VEGFR1 or anti-VCAM1 significantly reduced VEGF-induced leukostasis in the retinal vessels.

Conclusions : High levels of VEGF in the retina results in recruitment of leukocytes into retinal vessels in part due to stimulation of VEGFR1 on leukocytesandpromotes leukocyte adhesion due to upregulation of VCAM-1 in retinal endothelial cells, which in some areas plugs vessels resulting in retinal nonperfusion. The leukostasis and nonperfusionare reversed by cessation of VEGF expression. These data explain the mechanism of progressive nonperfusion in patients with ischemic retinopathies that is reversed by intraocular injections of anti-VEGF agents.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.

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