Researchers from University of Pennsylvania suggested that failure of liver to supply key lipids to the brain could contribute to Alzheimer’s risk.
Plasmalogens is a class of lipids created in the liver that are found in numerous human tissues, with particular enrichment in the nervous, immune, and cardiovascular system. These lipids are dispersed through the blood stream in the form of lipoproteins, throughout the body and are integral to cell membranes in the brain. According to new research by Mitchel A. Kling, MD, an associate professor of Psychiatry in the Perelman School of Medicine at the University of Pennsylvania presented at the Alzheimer’s Association International Conference (AAIC) 2018 from July 16-20, reduced levels of plasmalogens are associated with an increased risk of Alzheimer’s disease. The research lead author—Rima F. Kaddurah-Daouk, PhD, at Duke University School of Medicine, developed three indices— the ratios of plasmalogens to each other, the ratios of plasmalogens to their closely-related and more conventional lipid counterparts, and a combination of these two quantities—for measuring the amount of plasmalogens that are related to cognition.
Furthermore, the researchers measured several plasmalogens in blood-based fluids collected from two groups that comprised 1,547 subjects suffering from Alzheimer’s disease and subjects who were cognitively normal (CN). The plasmalogens primarily included 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. It was observed that lower values of these indices contributed to a higher risk of Alzheimer’s disease. Moreover, some of the decreased plasmalogen levels were associated with increased levels of the tau protein—a marker of Alzheimer’s disease, in the brain. The findings significantly highlight the potential relationship between obesity and diabetes and Alzheimer’s — as the liver functions to break down fatty acids. Moreover, they explain the lack of effect of fish oil or DHA administration on Alzheimer’s disease, owing to defect in the liver that prevents these fatty acids from becoming incorporated into the plasmalogens.