Altered composition of cerebral microvessel membrane phosphoglycerides from senescent mouse.

Phosphoglyceride and fatty acid composition was determined in the cellular membranes of isolated cerebral microvessels and brain parenchymal cells (neurons and glia) taken from 10-, 20-, and 27-30-month-old C57BL6/NNIA mice. Lipids were extracted from each fraction and the fatty acid profiles of ethanolamine, choline, serine, and inositol phosphoglycerides analyzed by gas chromatography. The results suggest that membrane phosphoglycerides from cerebral microvessels are significantly more affected by the aging process than are those of the brain parenchyma. Relative percentage for fatty acids in cerebral microvessels indicate an overall decline in membrane unsaturation with a concomitant elevation in the level of saturation. The decline in unsaturation is reflected primarily in the loss of precursor fatty acids for arachidonic (18:2n-6 and 20:3n-6) and docosahexaenoic (20:5n-3 and 22:5n-3) acids. Levels of arachidonic (20:4n-6) and docosahexaenoic (22:6n-3) acids in each phosphoglyceride remained unchanged with age; however, mol% for ethanolamine plasmalogen, a major source of these fatty acids, was significantly reduced in 27-30-month-old mice. Conversely, mol% for choline phosphoglyceride increased with age. The age-related changes in fatty acid profile for microvessel membrane phosphoglycerides are reflected by increased saturation/unsaturation ratios and decreased unsaturation indices. These parameters were not affected by aging in parenchymal membranes.