GRAND FORKS, ND—Several markers of age-related macular degeneration (AMD), including cholesterol deposits and amyloid beta formation, were elevated in animals fed a cholesterol-rich diet. The research was performed by scientists from University of North Dakota (UND) School of Medicine and Health Sciences and published in BMC Opthalmology (11(1):22).
AMD shares several mechanisms and biomarkers with Alzheimer’s disease (AD), including beta-amyloid (Abeta) accumulation, oxidative stress and apoptotic cell death. Based on prior research showing high plasma cholesterol correlates to increased incidence of AD, the UND researchers tested a cholesterol-rich diet in male New Zealand white rabbits for 12 weeks. After death, researchers examined the eyes of each rabbit, using one eye from each animal for immunohistochemistry analysis and the other eye for dissection and multiple analyses—Western blot, ELISA assays, spectrophotometry and mass spectrometry.
They found increased Abeta levels and reactive oxygen species (ROS) in the retinas from rabbits on high-cholesterol diets, compared to control-diet rabbits. In addition, astrogliosis, drusen-like debris and cholesterol accumulation were increased in the high-cholesterol group. They further found a dramatic increase in levels of oxysterols in retinas from cholesterol-fed rabbits—evidence suggests oxidized cholesterol metabolites (oxysterols) may be the link by which cholesterol contributes to the pathogenesis of AMD.
The scientists concluded cholesterol-enriched diets cause retinal degeneration relevant to AMD, and high-cholesterol levels coupled with subsequent increases in cholesterol metabolites are potential contributors to AMD.
