Abstract
Purpose: :
The presence of zinc has been qualitatively described in drusen. In our present study we determined the concentration of zinc, copper other trace elements in both peripheral and macular drusen from unfixed human donor eyes with drusen.
Methods: :
Frozen donor eyes were used from the Montana Eye Bank. Using a trephine, 6 mm diameter regions of the peripheral and central retinae were dissected. Following the removal of the neuronal retina, the retinal pigment epithelial cells and the choroid the remaining choroidal microcapillaries/Bruch’s membrane/drusen complex was analyzed by microprobe synchrotron X–ray fluorescence (uSXRF) at the X26A beam line at the National Synchrotron Light Source at Brookhaven National Laboratory. This method maps zinc, copper, and other trace metals in the tissues. In addition, several samples were first treated with ZP–1, and zinc specific fluorescent probe.
Results: :
We identified the presence of several trace elements in drusen both at the periphery end in the macula. The most highly concentrated were zinc and copper reaching maximal concentrations of ∼600 ppm and ∼150 ppm respectively. Bruch’s membrane also contained elevated levels of these trace elements compared to age matched control samples. ZP–1 staining correlated well with X–ray fluorescence.
Conclusions: :
Zinc, copper and other trace elements are enriched in drusen. ZP–1 is an effective tool to show the presence of zinc in post–mortem human eyes, and is useful for further investigations on the exact role of zinc the disease process of age–related macular degeneration.
Keywords: drusen • Bruch's membrane • age-related macular degeneration