Nanoparticle-Mediated Expression of an Angiogenic Inhibitor Ameliorates Ischemia-Induced Retinal Neovascularization and Diabetes-Induced Retinal Vascular Leakage

doi:10.2337/db08-1327

Nanoparticle-Mediated Expression of an Angiogenic Inhibitor Ameliorates Ischemia-Induced Retinal Neovascularization and Diabetes-Induced Retinal Vascular Leakage

¹Department of Medicine, Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma;
²Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska.

Corresponding author: Jian-xing Ma, jian-xing-ma{at}ouhsc.edu.

K.P. and Y.C. contributed equally to this study.

Abstract

OBJECTIVE The aim of the study is to evaluate the effect of nanoparticle-mediated gene delivery of angiogenic inhibitors on retinal inflammation, vascular leakage, and neovascularization in diabetic retinopathy.

RESEARCH DESIGN AND METHODS An expression plasmid of plasminogen kringle 5 (K5), a natural angiogenic inhibitor, was encapsulated with poly(lactide-coglycolide) to form K5 nanoparticles (K5-NP). Expression of K5 was determined by Western blot analysis and immunohistochemistry, and retinal vascular leakage was measured by permeability assay. Retinal neovascularization was evaluated using fluorescein-angiography and counting preretinal vascular cells in rats with oxygen-induced retinopathy. Effects of K5-NP on retinal inflammation were evaluated in streptozotocin-induced diabetic rats by leukostasis assay and Western blot analysis of intracellular adhesion molecule and vascular endothelial growth factor. Possible toxicities of K5-NP were evaluated using histology examination, retinal thickness measurement, and electroretinogram recording.

RESULTS K5-NP mediated efficient expression of K5 and specifically inhibited growth of endothelial cells. An intravitreal injection of K5-NP resulted in high-level expression of K5 in the inner retina of rats during the 4 weeks they were analyzed. Injection of K5-NP significantly reduced retinal vascular leakage and attenuated retinal neovascularization, when compared with the contralateral eyes injected with Control-NP in oxygen-induced retinopathy rats. K5-NP attenuated vascular endothelial growth factor and intracellular adhesion molecule-1 overexpression and reduced leukostasis and vascular leakage for at least 4 weeks after a single injection in the retina of streptozotocin-induced diabetic rats. No toxicities of K5-NP were detected to retinal structure and function.

CONCLUSIONS K5-NP mediates efficient and sustained K5 expression in the retina and has therapeutic potential for diabetic retinopathy.

Footnotes

The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
- Received September 27, 2008.
- Accepted May 4, 2009.
Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. See http://creativecommons.org/licenses/by-nc-nd/3.0/ for details.