Decreases of ethanolamine plasmalogen and phosphatidylcholine in erythrocyte are a common phenomenon in Alzheimer's, Parkinson's, and coronary artery diseases.

Decreased plasma levels of plasmalogens in neurodegenerative diseases have been watched with interest. We previously reported the decreases of erythrocyte ethanolamine plasmalogen (PlsPE) of blood not only in Alzheimer's disease (AD) and Parkinson's disease (PD), but also in coronary artery disease (CAD). In the present study, by using the same high-performance liquid chromatography (HPLC) method, we investigated the pattern of changes in the phospholipid composition of erythrocyte membrane in AD, PD and CAD compared with healthy individuals. The common patten of changes among them was as follows: The decrease of erythrocyte PlsPE was accompanied by a decrease of phosphatidylcholine although phosphatidylethanolamine remained unchanged. The decreases of PlsPE and phosphatidylcholine were replaced by an increase of sphingomyelin (SM) in the total phospholipids. The dissociated change between PlsPE and phosphatidylethanolamine (PE) may be caused by the differences in molecular structure or in location in the cell membrane. Such special changes provide another piece of biochemical evidence that these different diseases are caused by identical pathological mechanism, suggesting potential biomarkers for these chronic diseases due to aging.