Abstract
Purpose: :
To demonstrate that decreased levels of Glutathione S-Transferase Pi (GSTP1) are associated with human age-related macular degeneration (AMD) compared to normal retina. GSTP1 is an intracellular detoxification enzyme that catalyzes the reduction of electrophiles by conjugating chemically reactive electrophilic species to glutathione. It has been shown to be a zeaxanthin-binding protein in the human macula. A decrease in the GSTP1 levels may result in uncontrolled accumulation of reactive electrophiles, including reactive oxygen species, leading to AMD pathogenesis.
Methods: :
Human AMD and normal cadaver eyes (n=4 each) were used for preparation of tissue sections or for protein extraction from retina. Normal and AMD retinal sections were subjected to immunohistochemistry (IHC) using antibody against human GSTP1. Protein extracts from human AMD and normal retinas were subjected to Western blot analysis.
Results: :
IHC revealed decreased staining for GSTP1 in the AMD retina compared to normal control. This result was supported by the decreased GSTP1 protein levels in the AMD compared to normal retina by Western blot analysis.
Conclusions: :
These data demonstrated the involvement of GSTP1 activity in the normal functioning of retina and that a decrease in its expression may lead to AMD pathogenesis.
Keywords: age-related macular degeneration • oxidation/oxidative or free radical damage • enzymes/enzyme inhibitors