- Liver health affects the risk for Alzheimer's disease.
- Reduced levels of plasmalogens in the liver may heighten Alzheimer's disease risk.
- Plasmalogens are lipids created in the liver that are integral to cell membranes in the brain.
They measured several plasmalogens including those containing omega-3 fatty acids docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), as well as an omega-6 fatty acid and closely-related non-plasmalogen lipids, in blood-based fluids collected from two groups: the first included 1,547 subjects that have Alzheimer's disease, MCI or significant memory concerns (SMC), and subjects who were cognitively normal (CN) and who are enrolled in the Alzheimer's Disease Neuroimaging Initiative; the second included 112 subjects from the Penn Memory Center, including those with Alzheimer's, MCI, and CN.
The team observed that lower values of these indices were associated with a higher likelihood of Alzheimer's disease. A similar pattern was seen with MCI and CN associations. Additionally, some of the decreased plasmalogen levels were correlated with increased levels of the tau protein in the brain, a marker of Alzheimer's disease.
"This research shows that an age-related deficiency of plasmalogens could lead to an increased risk of Alzheimer's disease, because the liver cannot make enough of them," said Kling, who is also a fellow of the Institute on Aging. "This research has a variety of interesting implications. For example, it highlights a potential relationship between conditions such as obesity and diabetes and Alzheimer's, as the liver has to work harder to break down fatty acids over time. This could lead to the eventual destruction of the peroxisomes that create plasmalogens which thus, increases the risk of Alzheimer's."
The findings also provide a possible explanation for the observed lack of effect of fish oil or DHA administration on cognitive function or Alzheimer's disease, which has been shown in other studies. This is due to the defect in the liver that prevents these fatty acids from becoming incorporated into the plasmalogens that are critical for synaptic function in brain, which can affect cognition. Several of the genes associated with Alzheimer's are involved in lipid transport or metabolism, therefore ongoing research is looking to see how changes in the production or transport of lipids affect brain structure and function.
References:
- Alzheimer's Disease Risk Impacted by the Liver, Diet - (https://www.ucnews.in/news/Alzheimers-disease-risk-impacted-by-the-liver-diet/4388997711857953.html)