Retinal pigment epithelium (RPE) from humans of all ages has been prepared for ultrastructural examination. Now, using morphometric methds we will quantify subcellular organelles, e.g. lipofuscin, melanin, lysosomes, melanolysosomes, melanolipofuscin, etc. in RPE of macular, equatoria and peripheral retina.
The aim i s to estimate the normal composition of RPE constituents at each decade of life to aid in future interpretations of RPE abnormalities. Lipofuscin and other complex granules (above) will be isolated on sucrose gradients from pairs of human Eye Bank eyes and analyzed morphologically and biochemically. Chromatography will be used to separate fluorescent compounds from extracts of granules. Tests will be run to determine if peroxidized lipids, substances with conjugated Schiff bases, retinoyl compounds, etc. can be identified as contributors to observed lipofuscin fluorescence. The role of diet in the formation of components of fluorescent RPE granules will be explored using eyes of chicks or rats maintained on diets deficient in selenium, vitamin E, and other antioxidants. Putative precursors of lipofuscin, i.e. phagocytized photoreceptor outer segments, will be radiolableled and the phagolysosomes/lipofuscin granules, produced in the RPE by either in vivo or in vitro phagocytosis, will be isolated by cell fractionation and sucrose gradient centrifugation. Isolated granules will be extracted and chromatographed; autoradiographs will be made and analyzed for sources of fluorescent and radioactive molecules. RCS rats that have inherited retinal dystrophy and fail to phagocytize outer segments have been shown to also have diminished RPE retinol esterifying enzyme activity (Berman et al. 1980). We will test the postulate that this enzyme deficiency leads to abnormalities in glycoproteins required for phagocytosis. Collaborative studies of monkey maculas and cystic fibrosis RPE will continue. This research is aimed at clarifying cellular aspects of senile macular degeneration, retinitis pigmentosa, and other retinal diseases.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
2R01EY003274-09A1
Application #
3257577
Study Section
Visual Sciences A Study Section (VISA)
Project Start
1979-05-01
Project End
1992-09-29
Budget Start
1987-09-30
Budget End
1988-09-29
Support Year
9
Fiscal Year
1987
Total Cost
Indirect Cost
Name
University of Missouri-Columbia
Department
Type
Schools of Medicine
DUNS #
112205955
City
Columbia
State
MO
Country
United States
Zip Code
65211
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Katz, M L; Norberg, M; Stientjes, H J (1992) Reduced phagosomal content of the retinal pigment epithelium in response to retinoid deprivation. Invest Ophthalmol Vis Sci 33:2612-8
Feeney-Burns, L; Burns, R P; Gao, C L (1990) Age-related macular changes in humans over 90 years old. Am J Ophthalmol 109:265-78
Feeney-Burns, L; Neuringer, M; Gao, C L (1989) Macular pathology in monkeys fed semipurified diets. Prog Clin Biol Res 314:601-22
Feeney-Burns, L; Gao, C L; Berman, E R (1988) The fate of immunoreactive opsin following phagocytosis by pigment epithelium in human and monkey retinas. Invest Ophthalmol Vis Sci 29:708-19
Organisciak, D T; Berman, E R; Wang, H M et al. (1987) Vitamin E in human neural retina and retinal pigment epithelium: effect of age. Curr Eye Res 6:1051-5
Feeney-Burns, L; Gao, C L; Tidwell, M (1987) Lysosomal enzyme cytochemistry of human RPE, Bruch's membrane and drusen. Invest Ophthalmol Vis Sci 28:1138-47
Feeney-Burns, L; Ellersieck, M R (1985) Age-related changes in the ultrastructure of Bruch's membrane. Am J Ophthalmol 100:686-97
Feeney-Burns, L (1985) The early years of research. Prog Clin Biol Res 190:3-23