Platelets and aging. II--Plasma lipoproteins and fatty acid profiles

Lipid composition of both plasma and platelets were investigated in sixteen old (78-94 years) and eight young (25-35 years) subjects. No age-related change was noted in plasma total and HDL cholesterol whereas a slightly increase of triglycerides was observed in the elderly population. Level of apo AI tended to decrease while apo AII decreased significantly in the elderly. These results led to a higher apo AI/apo AII ratio in elder subjects. However, no difference was detected in the level of apo B. In contrast, several modifications appeared in fatty acid composition of plasma lipids. Primarily, monounsaturated fatty acids content was increased while level of linoleic acid (and arachidonic acid in phospholipids) decreased in each class of plasma lipids of elderly subjects. In platelets from the elderly, we found an enhancement of monounsaturated fatty acids in phosphatidyl-inositol (PI), -ethanolamine (PE) and -choline (PC). The decrease of linoleic acid was detected in PC while the reduction of AA was noted in PE. These results indicate that modifications of fatty acid composition in both plasma and platelet lipids appeared with aging. They might be linked to the enhanced platelet activation in vivo observed in elderly people.