Abstract
Purpose::
To examine changes in the retinal pigment epithelium (RPE) from age related macular degeneration (AMD) eyes, and specifically to characterize alphaB-crystallin expression in RPE cells as a biomarker in this disease.
Methods::
Maculas from human patients diagnosed with AMD and age-matched normal eyes were isolated, cryosectioned, and analyzed immunohistochemically for alphaB-crystallin and cell-type specific markers.
Results::
In dry and wet AMD eyes, alphaB-crystallin was heterogeneously expressed by a sub-population of RPE cells in the macular region, frequently in cells in direct contact with drusen, and in areas of RPE hypertrophy associated with wet AMD. In contrast, alphaB-crystallin was not detected at significant levels in normal RPE.
Conclusions::
RPE cells change to express alphaB-crystallin accompanying drusen formation in early and in late stage AMD. alphaB-crystallin is expressed in a cell-by-cell manner, indicating that changes occur in individual RPE cells in AMD and not in the RPE layer as a whole. The detection of alphaB-crystallin in RPE of patients with early and advanced AMD implicates this as an AMD biomarker. Sporadic expression of alphaB-crystallin by RPE cells localized adjacent to drusen in early AMD indicates that changes in RPE cell gene expression accompany early stages of the disease, and introduces novel potential targets for AMD therapy.
Keywords: age-related macular degeneration • retinal pigment epithelium • crystallins