Abstract
Purpose:
To investigate the chemical composition and fluorophores of human retinal lipofuscin for a better understanding of age related macular degeneration (AMD). Additional purpose is to examine the differences in composition of extracts of donor tissue diagnosed as wet and dry AMD.
Methods:
Human retinal lipofuscin is extracted from human donor eyes diagnosed with either wet or dry AMD as previously described by Feeney-Burns. The organic soluble lipofuscin is collected, dried, and reconstituted with methanol for use in high performance liquid chromatography tandem mass spectrometry (LC/MS) coupled with a fluorescent detector (Surveyor LC with PDA, Thermo Finnigan LCQ Advantage MS, Surveyor FL). Mass spectrometry data is analyzed in parallel with fluorescence data to determine novel fluorophores for use in diagnostic techniques. Tandem mass spectrometry data is analyzed for the investigation of chemical composition specific to wet and dry AMD.
Results:
Lipofuscin extracts from human donor tissue diagnosed as wet and dry AMD have been subjected to LC/MS. Total ion chromatograms observed from LC/MS analysis suggests unique compositions for wet and dry AMD. The extensively studied fluorophore, A2E, was not observed in lipofuscin extracts diagnosed as dry AMD. However, A2E and its derivatives were observed in extracts diagnosed as wet AMD and verified by analysis of fragmentation patterns.
Conclusions:
Some fluorophores of lipofuscin from AMD diagnosed tissue have been determined. The lipofuscin extracted from tissue diagnosed as wet and dry AMD suggest different chemical composition. This proposes the possibility that wet and dry AMD are actually two different diseases. Analysis of an undefined AMD lipofuscin extract shows similarity to data obtained for dry AMD. Understanding the chemical composition and fluorophores found in these samples can aid in furthering the treatment, diagnosis and prevention of wet and dry AMD.
Keywords: 582 ipofuscin •
412 age-related macular degeneration •
701 retinal pigment epithelium