Investigation of alteration in erythrocyte lipids in people at ultra high risk of developing psychosis

Consumption of n-3 long chain polyunsaturated fatty acids (n-3 LCPUFA) is associated with higher n-3 LCPUFA status in the circulation, which has in turn has been associated with a number of health benefits in humans. n-3 LCPUFA cardiovascular health benefits are well known and there is emerging evidence for mental health benefits. Limited studies have indicated that there is a positive correlation between an improvement of Ultra-High-Risk (UHR) of developing psychosis symptoms and the intake of n-3 LCPUFA; however there is a need for further studies involving larger randomized-controlled studies since the previous work was conducted with low numbers. These studies have also shown that people classified as UHR of developing psychosis have reduced n-3 PUFA, n-6 PUFA and n-3 index. What is unknown is the molecular phospholipid data and how that data may relate to developing psychosis and also how this is affected by n-3 LCPUFA supplementation

A High-Throughput Method for the Analysis of Erythrocyte Fatty Acids and the Omega-3 Index

Omega-3 long-chain polyunsaturated fatty acids (n-3 LCPUFA) have several health benefits. In particular, low n-3 LCPUFA status is associated with cardiovascular disease (CVD) and led to the development of the omega-3 index that is the proportion of eicosapentaenoic acid and docosahexaenoic acid in the erythrocyte membranes, as a marker of CVD risk. Most methods used to measure the omega-3 index are laborious and time consuming. Therefore, the aim of this study was to develop a high-throughput method for the extraction and measurement of erythrocyte fatty acids and the omega-3 index. For sample extraction and quantification, two methods were used; a single-step extraction, degradation, and derivatization method by Lepage and Roy, followed by gas chromatography flame ionization detection (GC-FID), which is commonly used and a high-throughput method using an automated methyl tert-butyl ether extraction followed by electrospray ionization mass spectrometry. Both methods were first applied to the analysis of known concentrations of synthetic phospholipid (PL) mixtures to determine recovery and precision prior to their application in the analysis of human erythrocytes. The range of recoveries over five synthetic PL mixtures were 86.4–108.9% and the coefficient of variation wa

Discrimination of isobaric and isomeric lipids in complex mixtures by combining ultra-high pressure liquid chromatography with collision and ozone-induced dissociation

The inability of current mass spectrometry techniques to differentiate phospholipid isomers results in a routine under-estimation of phospholipid molecular diversity in complex biological matrices. Recent technological advances in tandem mass spectrometry and ion activation are helping to overcome these limitations, but all rely on tandem mass spectrometry with unit mass-selection and suffer from co-isolation of isobaric or isomeric species. Accordingly, separation of phospholipid isomers and isobars prior to characterization is required to fully delve into the complexity of the lipidome. Here we present a novel two-stage workflow combining reversed-phase ultra-high performance liquid chromatography with ozone-induced dissociation (OzID) and combined-collision- and ozone-induced-dissociation (COzID) that reduces spectral complexity and enables discrimination of lipid isomers and isobars. Application of this technique to the analysis of human red blood cell lipid extracts allowed the separation, or partial separation, of adduct ion and head group isobars as well as double bond and sn-positional isomers affording near complete structural characterization of low abundance lipids, e.g. PC 18:0/20:3(n-6), PS 18:0/20:4(n-6) and PS 20:4(n-6)/18:0 all observed at m/z 834.7. We also introduce a software plug-in that automatically annotates OzID mass spectra to assign the carbon–carbon double bond positions in lipids. This new workflow allows us to delve deeper into the lipidome and represents another valuable tool for the lipidomics toolbox

Comparison of erythrocyte omega-3 index, fatty acids and molecular phospholipid species in people at ultra-high risk of developing psychosis and healthy people

© 2019 People classified as ultra-high risk (UHR) of developing psychosis have reduced cellular membrane omega-3 and omega-6 polyunsaturated fatty acids (PUFA). We aimed to compare omega-3 index, fatty acids and molecular phospholipid species from erythrocytes of people with UHR (n = 285) with age-matched healthy controls (n = 120) assessed by mass spectrometry. Lower proportions of PUFA were observed in the UHR group compared to healthy controls; specifically, eicosapentaenoic acid (EPA) was 29.3% lower, docosahexaenoic acid (DHA) was 27.2% lower, arachidonic acid (AA) was 15.8% lower and the omega-3 index was 26.9% lower. The AA to EPA ratio was higher in the UHR group compared to the healthy group. Smoking status had no significant effect on PUFA levels in healthy or the UHR groups. BMI was associated with PUFA levels in the UHR group only and the statistical model only explains 2% of the variance of the PUFA levels. The proportion of nervonic acid was 64.4% higher in the UHR group compared to healthy controls. At a lipid class level, the UHR group had 16% higher concentrations of sphingomyelin (SM) and 46% lower concentrations phosphatidylethanolamine (PE) compared to healthy group. Of the 49 individual molecular phospholipids, twenty-seven phospholipid species were lower in the UHR group. In conclusion, there are clear differences in the proportions of erythrocyte fatty acids and phospholipids between UHR and healthy controls and UHR had higher concentrations of SM and lower concentrations of PE. These differences may represent a promising prodromal risk biomarker in the UHR population to aid clinical diagnosis

Supplementation with the omega-3 long chain polyunsaturated fatty acids: Changes in the concentrations of omega-3 index, fatty acids and molecular phospholipids of people at ultra high risk of developing psychosis

© 2019 Omega-3 long chain polyunsaturated fatty acids (n-3 LCPUFA) are necessary for optimum mental health, with recent studies showing low n-3 LCPUFA in people at ultra-high risk (UHR) of developing psychosis. Furthermore, people at UHR of psychosis had increased erythrocyte sphingomyelin (SM) and reduced phosphatidylethanolamine (PE) concentrations as well as 27 erythrocyte phospholipid species that differed when compared to erythrocytes from age matched people not at UHR of psychosis. The aim of this analysis was to evaluate the effect of n-3 supplementation on the different erythrocyte lipid species (including SM and PE concentrations) in people at UHR of psychosis. Participants were randomly assigned to fish oil (containing 840 mg EPA and 560 mg DHA per day) or placebo (paraffin oil) for 6 months. Fasted blood samples were taken at baseline and post intervention. Mass spectrometry was used to analyse the molecular phospholipids and fatty acid composition of erythrocytes for both groups. The n-3 index was significantly increased from 3.0% to 4.12% after 6 months of receiving n-3 capsules. Fish oil capsules increased the phospholipid molecular species containing n-3 LCPUFA, and concomitant decreases in n-6 LCPUFA species. SM species did not show any significant changes in n-3 LCPUFA group however, three SM species (SM 16:0, SM 18:0, SM 18:1) significantly increased after 6 months of supplementation with placebo. N-3 supplementation for 6 months led to higher n-3 incorporation into erythrocytes, at the expense of n-6 PUFA across all phospholipid classes analyzed and may have prevented the increase in SM seen in the placebo group

Supplementation with the omega-3 long chain polyunsaturated fatty acids: Changes in the concentrations of omega-3 index, fatty acids and molecular phospholipids of people at ultra high risk of developing psychosis

Omega-3 long chain polyunsaturated fatty acids (n-3 LCPUFA) are necessary for optimum mental health, with recent studies showing low n-3 LCPUFA in people at ultra-high risk (UHR) of developing psychosis. Furthermore, people at UHR of psychosis had increased erythrocyte sphingomyelin (SM) and reduced phosphatidylethanolamine (PE) concentrations as well as 27 erythrocyte phospholipid species that differed when compared to erythrocytes from age matched people not at UHR of psychosis. The aim of this analysis was to evaluate the effect of n-3 supplementation on the different erythrocyte lipid species (including SM and PE concentrations) in people at UHR of psychosis. Participants were randomly assigned to fish oil (containing 840 mg EPA and 560 mg DHA per day) or placebo (paraffin oil) for 6 months. Fasted blood samples were taken at baseline and post intervention. Mass spectrometry was used to analyse the molecular phospholipids and fatty acid composition of erythrocytes for both groups. The n-3 index was significantly increased from 3.0% to 4.12% after 6 months of receiving n-3 capsules. Fish oil capsules increased the phospholipid molecular species containing n-3 LCPUFA, and concomitant decreases in n-6 LCPUFA species. SM species did not show any significant changes in n-3 LCPUFA group however, three SM species (SM 16:0, SM 18:0, SM 18:1) significantly increased after 6 months of supplementation with placebo. N-3 supplementation for 6 months led to higher n-3 incorporation into erythrocytes, at the expense of n-6 PUFA across all phospholipid classes analyzed and may have prevented the increase in SM seen in the placebo group