Abstract
Purpose: :
Age-related macular degeneration (AMD) is a leading cause of vision loss in subjects 60 yrs and older. It occurs in "dry" and "wet" forms. the presence of drusen in the macula is a common early sign of AMD. Many studies have confirmed that the presence of the drusen, mainly large drusen ( gray-yellow deposits that build up in or around the macula of the retina), represents a n important risk factor for visual loss in AMD patients. Recent characterizations of drusen have revealed protein and lipid components that are similar with β-amyloid (Aβ) deposits found in neuronal cells from patients with Alzheimer disease (AD). Starting from recent studies showing that in AMD patients modifications in cholesterol esters formation appear in peripheral blood mononuclear cells (PBMCs) we compared cholesterol esters content in PBMCs of AMD patients with dry form with those with wet form.
Methods: :
PBMCs were obtained from 53 patients with AMD (35 with dry form and 18 with wet form) aged between 64-93 years and 35 age matched controls. Cells were then treated with isopropyl alcohol (60%), washed, stained with oil red O (ORO) for intracellular neutral lipid quantization and counterstained with Mayer’s hematoxylin. Stained cells were examined by light microscopy.
Results: :
Quantitative analysis with ORO staining performed on samples from AMD patients and controls indicated a significant increase of neutral lipid levels (mainly cholesterol esters) in AMD in comparison with non-AMD, however, cholesterol esterification (CE) levels were significantly higher in dry AMD compared to wet AMD (3.1±0.9 vs. 1.4± 1.0, respectively). Of interest, none of AMD patients utilized in this study showed cognitive alteration as determined by the Mini Mental State Examination (MMSE) scores.
Conclusions: :
We suggest that abnormal CE could represent a predisposing factor in the development of AMD. The alteration in CE levels in PBMCs may indicate that pathological process involving abnormal activation, and/or trafficking of membrane resident protein may be correlated to AMD process . This study present the first evidence of a link between cholesterol esters in PBMCs and the dry AMD, indicating CE pathway as new target for therapy.
Keywords: age-related macular degeneration • lipids • clinical laboratory testing