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Plasmalogens are created in the liver and are dispersed through the blood stream in the form of lipoproteins, which also transport cholesterol and other lipids to and from cells and tissues throughout the body, including the brain. Low levels of plasmalogens- a class of lipids created in the liver that are integral to cell membranes in the brain are associated with an increased risk of Alzheimer’s Disease.
Researchers measured the ratios of plasmalogens to each other, the ratios of plasmalogens to their closely-related, more conventional lipid counterparts; and a combination of these two quantities. 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 Alzheimer’s patients that have significant memory concerns SMC and those who were cognitively normal (CN).
They 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.
An age-related deficiency of plasmalogens could lead to an increased risk of Alzheimer’s disease, because the liver cannot make enough of them. The research showed how obesity, diabetes and Alzheimer’s relate the liver has to work harder to break fatty acids over time. This could lead to the eventual destruction of the peroxisomes that create plasmalogens which increases the risk of Alzheimer’s disease.
It also explained the effect of fish oil or DHA administration on cognitive function or Alzheimer’s disease, which 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. Some of the genes associated with Alzheimer’s are involved in lipid transport or metabolism.