Brain membrane phospholipid alterations in Alzheimer's disease

Studies have demonstrated alterations in brain membrane phospholipid metabo lite levels in Alzheimer's disease (AD). The changes in phospholipid metabo lite levels correlate with neuropathological hallmarks of the disease and m easures of cognitive decline. This P-31 nuclear magnetic resonance (NMR) st udy of Folch extracts of autopsy material reveals significant reductions in AD brain levels of phosphatidylethanolamine (PtdEtn) and phosphatidylinosi tol (PtdIns), and elevations in sphingomyelin (SPH) and the plasmalogen der ivative of PtdEtn. In the superior temporal gyrus, there were additional re ductions in the levels of diphosphatidyl-glycerol (DPG) and phosphatidic ac id (PtdA). The findings are present in 3/3 as well as 3/4 and 4/4 apolipopr otein E (apoE) genotypes. The AD findings do not appear to reflect non-spec ific neurodegeneration or the presence of gliosis. The present findings cou ld possibly contribute to an abnormal membrane repair in AD brains which ul timately results in synaptic loss and the aggregation of A beta peptide.