Alzheimer’s disease (AD) is caused by a combination of genetic and environmental factors affecting the brain in the longer term. It has been suspected that capillaries in the brain may play a role in AD, as they are responsible for delivering nutrients and oxygen and removing waste products. A variant of the APOE gene (APOE4) is the most prevalent genetic risk for AD, which is seen to modify brain capillaries in mice, potentially contributing to AD pathogenesis.
As the in vivo method cannot directly conceptualise human brain capillaries, this study used retinal imaging to examine the effects of APOE4 on capillaries at the back of the eye and whether it could be detected early in asymptomatic individuals.
The team discovered that those who are APOE4 carriers had a reduction in capillary density. When compared to the retinal capillaries in participants with and without amyloid plaques in the brain, no difference was found between the two groups.
Why it matters: Being able to identify that the retinal capillaries are reduced in APOE4 carriers leads to the understanding that the increased risk of AD in APOE4 carriers may be due to the effects it has on blood capillaries. These findings provide a method of early AD detection and thus allowing early intervention, increasing the chances of overcoming neurodegenerative diseases.
Source: Alzheimer's Association