Inherent Lipid Composition Abnormalities in Astrocytes Associated with Late-Onset Alzheimer's Disease (LOAD)

Lipid abnormalities have been observed in brain, cerebrospinal fluid (CSF), and blood in association with late-onset Alzheimer's disease (LOAD). It is unknown which of these abnormalities are precursors to LOAD and which are concomitants of illness or its treatment. Inherent abnormalities can be identified in induced pluripotent stem cell (iPSC)-derived brain cells. These cells lack markers associated with aging and environmental exposures. The iPSC lines of patients with LOAD or healthy individuals were differentiated to astrocytes. Astrocytes are crucial to neural activity and health, and altered astrocyte functions are associated with LOAD pathology. Lipidomics analyses were performed on whole-cell and mitochondria-enriched fractions. Large reductions in cholesterol esters (CEs) and imbalances in fatty acids (FAs) were observed in LOAD-associated cells or their mitochondria. There were only modest differences in other lipid classes, including membrane structural lipids. The findings identify abnormalities in CEs, as well as in FAs, as inherent abnormalities and likely precursors to LOAD. These differences implicate mechanisms contributing to disease pathogenesis. Further study may lead to early interventions to prevent or delay LOAD.