Global fatty acid composition is altered in Parkinson's disease anterior cingulate cortex
Purpose: We previously demonstrated significant reductions in sphingolipid levels and fatty acyl chain length in Parkinson's disease (PD) grey matter anterior cingulate cortex (ACC). The aim of the present study was to explore whether these changes were sphingolipid-specific. Methods: Lipids were extracted from frozen ACC and occipital cortex (OCC) from PD patients (n=9) and age-matched controls (n=10), from the Sydney Brain Bank (supported by Neuroscience Research Australia, University of New South Wales and National Health and Medical Research Council of Australia). Total lipid fatty acid (FA) methyl esters were analysed by gas chromatography. Results: In both ACC and OCC 14 FAs were identified. A significant decrease in total FA concentration (pmol/mg tissue) in PD was observed for ACC only (26%), with reductions in 10 individual FAs. FA relative abundance (mol%) was also only altered in ACC (significant changes in 11 FAs). The degree of change between PD and controls (mol%) was greater for sphingolipids than total FA composition, i.e. the mean mol% change for sphingolipids was 4% while for FAs it was 1%. Polyunsaturated FAs were increased in PD (6%) and peroxidation index was also increased (31%), indicating increased predicted susceptibility of PD ACC to peroxidative damage. Conclusion: Although changes in total FA composition were similar to sphingolipids in PD ACC, the degree of change in fatty acyl composition was much greater in sphingolipids, indicating that altered sphingolipid metabolism in PD may be particularly important. Altered global ACC FA composition may contribute to increased lipid peroxidation in PD.