Abstract
Purpose:
To investigate the chemical composition of Folch extracts of human retinal lipofuscin from human donor tissue diagnosed as neovascular (wet) or avascular (dry) age related macular degeneration (AMD).
Methods:
Human retinal lipofuscin is extracted from human donor eyes diagnosed with either wet or dry AMD as previously described by Feeney-Burns (Feeney-Burns and Eldred, 1983). The organic soluble portion of lipofuscin is collected, dried, and reconstituted with methanol for analysis by high resolution, high performance liquid chromatography (LC/MS) tandem mass spectrometry. LC/MS and tandem mass spectrometry data is analyzed in comparison to age matched donors to determine the chemical composition specific to wet and dry AMD. Biomarkers specific to inflammation have been identified.
Results:
Analysis of the mass chromatograms alongside photodiode array and fluorescence chromatograms show unique components for the samples from diseased tissue compared to those samples from age matched donors. <br /> Additional analysis of dry AMD diagnosed extracts have shown a higher prevalence for L-homocitrulline compared to that of an age matched donor. Increased levels of L-homocitrulline have been associated with inflammation.
Conclusions:
These data suggest that wet and dry AMD may be two different diseases. Additionally, increased levels of L-homocitrulline have been detected in the dry AMD diagnosed extracts supporting inflammation as a possible contributor to the progression of the disease. Understanding the chemical composition found in these samples can aid in understanding the pathogenesis of wet and dry AMD.