Abstract
Abstract: :
Purpose: In a study of the proteome of drusen, clusterin (also known as apolipoprotein J) was identified by liquid chromatography tandem mass spectometry as a possible drusen protein. The goal of this study is to define the distribution of clusterin in drusen and Bruch's membrane. Methods: Nineteen normal donor eyes (age 16 - 95) and 13 age-related macular degeneration (AMD) eyes (age 72 - 96) were used for immunocytochemistry. Frozen sections were prepared from the eyes and stained with a commercial clusterin antibody. Western blotting was performed on samples from 7 fresh normal donor eyes (age 15 - 91). RT-PCR was performed on RNA isolated from retina, retinal pigment epithelium (RPE) and Bruch's membrane/choroid complex. Results: Clusterin immunoreactivity was evident in drusen, Bruch's membrane and choroid. In normal eyes, clusterin immunoreactivity was present throughout drusen and also in Bruch's membrane. In AMD eyes, some drusen did not show clusterin immunoreactivity. Western blot analysis revealed several clusterin immunoreactive bands at all ages in Bruch's membrane/choroid complex. RT-PCR showed the expression of clusterin by the retina, RPE and Bruch's membrane/choroid complex. Conclusion: Although the function of clusterin is not known, it is thought to alter apoptosis, lipid transport, tissue remodeling, complement inhibition, and chaperone-like activity. Our findings of clusterin at the outer retinal border and its accumulation in drusen suggest a role in drusen formation and/or the development of AMD.
Keywords: 333 Bruch's membrane • 391 drusen • 567 retinal pigment epithelium