Risk of Alzheimer's disease increases with reduction in levels of plasmalogens, a class of lipids produced by the liver that constitute cell membranes in the brain, confirms new research presented at the Alzheimer's Association International Conference (AAIC) 2018 by Mitchel A. Kling, MD, an associate professor of Psychiatry in the Perelman School of Medicine at the University of Pennsylvania and the Veterans Affairs Medical Center.

Kling, and the multi-institutional Alzheimer's Disease Metabolomics Consortium headed by Rima F. Kaddurah-Daouk, PhD, at Duke University School of Medicine, worked on three indices for calculating the amount of plasmalogens associated with cognition, to check whether decreased values in the bloodstream are related to a higher risk of Alzheimer's disease, mild cognitive impairment (MCI), on the whole cognitive function, and/or other biomarkers of neurodegeneration in Alzheimer's disease. The three indices that were 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.

The team found that lower levels of the indices were linked with a higher risk of Alzheimer's disease. MCI and CN associations showed a similar picture. Moreover, some of the reduced plasmalogen levels were concurrent with increased levels of the tau protein in the brain, a biomarker 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.