Blue LED light irradiation and A2E perturb mitochondrial morphology and function in retinal pigment epithelial cells. New insights into the pathogenesis of Age-Related Macular Degeneration

ALAIMO A; BUJJAMER JM; GARCIA LIÑARES GUADALUPE; GOROJOD RM; PORTE ALCON S; BALDESSARI A; GRECCO HE; KOTLER ML

Mar del Plata

Congreso; LXI ANNUAL MEETING ARGENTINE SOCIETY FOR CLINICAL INVESTIGATION (SAIC); 2016

ARGENTINE SOCIETY FOR CLINICAL INVESTIGATION (SAIC)

Age-related macular degeneration (AMD) is a neurodegenerative disease of the elderly. AMD pathogenesis is characterized by retinal pigment epithelium (RPE) degeneration that progress with the light exposure-induced injury. RPE cells accumulate lipofuscin which contributes to their susceptibility to photo-oxidation. Blue light reaches deep into the eye causing cumulative retinal damage and increased AMD risk. Here, we studied the effect of blue light and A2E (major component of lipofuscin) on mitochondrial integrity in the RPE. Human ARPE-19 cells were exposed to blue light (LED λ=445nm; 1.7mW/cm2) for 1-30min and incubated for an additional 24h. The following parameters were studied: mitochondrial metabolic activity (MTT assay), generation of ROS (DCFDA probe) and superoxide (O2?-) (MitoSOX probe) (fluorometry and fluorescence microscopy), mitochondrial mass and shape-changes quantification (Tom-20 ICC/ Mito-Morphology ImageJ Macro). Blue light significantly reduced RPE viability (1min: 89±6%, 5min: 81±2%, 15min: 76±2% 30min: 52±5%) while increased intracellular ROS levels (1min: 34±6%, 5min: 37±2%, 15min: 45±13%, 30min: 53±4%). An early increment in O2?- levels occurred after 1min (74%, p