Glaucoma is a neurodegenerative disorder that is the leading cause of blindness in the world. While current treatments are aimed toward reducing the intraocular pressure (lOP), neurodegeneration sometimes continues even with a reduction in lOP. One of the mechanisms that may lead to the selective destruction of retinal ganglion cells is a glutamate-mediated excitotoxicity. Unfortunately, current methods for measuring glutamate in eye tissues do not provide all The desired spatial resolution for characterizing retinal glutamate levels and their potential sources. The goal of this proposal is to develop and demonstrate a novel, in vivo sampling system that provides the needed spatial localization for characterizing vitreal glutamate levels in a rat model of glaucoma. In the first phase of this project, a miniaturized, low-flow push-pull perfusion method and an appropriate capillary electrophoresis assay for glutamate that have been developed in our lab will be adapted for use in the vitreous. The spatial resolution of our low-flow push-pull perfusion will be used to characterize glutamate levels at sites in the central vitreous and vitreoretinal interface. Additionally, the source and dynamics of glutamate levels at the probe tip will be assessed by the inclusion of pharmacological agents into the perfusion solution. In the second phase of this project, the sampling method will be used to address the hypothesis that glutamate levels increase in specific locations at the retina in response to a chronic, moderate increase in lOP in a rat model of glaucoma. Measurements of vitreoretinal glutamate levels will be performed at central and peripheral sites of the retina during the first two weeks of a moderate increase in lOP. The outcomes of this project will be the introduction of a new tool for in vivo sampling in eye tissues and will provide previously inaccessible information regarding the neurobiology of glutamate at the glaucomatous retina. Further, the ability to characterize chemical composition at the retina demonstrated in this study may be applicable to innovative studies of other diseases of the retina.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Small Research Grants (R03)
Project #
5R03EY014908-02
Application #
6774101
Study Section
Special Emphasis Panel (ZEY1-VSN (01))
Program Officer
Liberman, Ellen S
Project Start
2003-08-01
Project End
2006-07-31
Budget Start
2004-08-01
Budget End
2005-07-31
Support Year
2
Fiscal Year
2004
Total Cost
$147,179
Indirect Cost
Name
University of Illinois at Chicago
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
098987217
City
Chicago
State
IL
Country
United States
Zip Code
60612
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Bertram, K M; Bula, D V; Pulido, J S et al. (2008) Amino-acid levels in subretinal and vitreous fluid of patients with retinal detachment. Eye 22:582-9
Myasein, Kyaw ThetMaw; Pulido, Jose S; Hatfield, R Mark et al. (2007) Sub-microlitre dialysis system to enable trace level peptide detection from volume-limited biological samples using MALDI-TOF-MS. Analyst 132:1046-52
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Gao, Leyi; Patterson 2nd, Eric E; Shippy, Scott A (2006) Multiplexed detection of nitrate and nitrite for capillary electrophoresis with an automated device for high injection efficiency. Analyst 131:222-8
Zhao, Xiaoyan; Barber-Singh, Jennifer; Shippy, Scott A (2004) MALDI-TOF MS detection of dilute, volume-limited peptide samples with physiological salt levels. Analyst 129:817-22
Thongkhao-On, Kongthong; Kottegoda, Sumith; Pulido, Jose S et al. (2004) Determination of amino acids in rat vitreous perfusates by capillary electrophoresis. Electrophoresis 25:2978-84