Plasma Lipid Species Research Articles

A simple and rapid extraction of lipids in plasma using spin column with superabsorbent polymer beads for mass spectrometry

The efficient extraction of lipid species in plasma was developed for quick sample preparation and accurate lipid analysis, using spin column with superabsorbent polymer beads (SAP), as the improvement of previous SAP method reported before. The modified SAP (mSAP) method is composed of simple steps, including sample loading, swelling, solvent addition, centrifugation, and drying of the resulting lipid solution. The mSAP method offers several advantages over the conventional and the previous SAP methods for lipid analysis in plasma sample. The mSAP method was approximately 10 times faster than the modified Folch protocol (Matyash method), methyl-tert-butyl ether based extraction method. The mSAP method offered an excellent recovery rate for most all major classes in the lipid standard mixture, outperforming the Matyash method. The limit of detection (LOD) of 1,2-diheptadecanoyl-sn-glycero-3-phophocholine (PC 17:0/17:0) spiking in plasma by the mSAP method is about seven times lower than those of the conventional methods. The relative standard deviation (RSD) values for inter- and intra-day variability of the mSAP method over a 5-day period were significantly lower than those of the previous SAP and Matyash methods. The mSAP method has been shown to be more time-saving, sensitive, reproducible and reliable, as evidence by its faster processing time, lower LOD, lower RSD values and high recovery rate for different lipid classes. Overall, these findings suggest that this method may be a promising approach for the application of total lipid analysis in lipidomic research in future.

Lipidomics Reveals Elevated Plasmalogens in Women with Obesity Who Develop Preeclampsia.

Objective: Preeclampsia (PE) is a prevalent pregnancy disorder worldwide with limited preventative treatments available. Obesity triples the risk for PE, yet only 10% of women with obesity develop PE. The factors that distinguish PE from uncomplicated pregnancies in the context of obesity have not been fully established. Methods: We studied a cohort of women with obesity throughout pregnancy to identify lipid mediators and/or biomarkers of PE. Blood samples were collected at each trimester and analyzed by both targeted lipidomics and standard lipid panels. Individual lipid species were compared by PE status at each trimester, as well as by self-identified race (Black vs. White) and fetal sex. Results: Standard lipid panels and clinical measurements revealed few differences between PE and uncomplicated pregnancies. Targeted lipidomics, however, identified plasmalogen, phosphatidylethanolamine, and free fatty acid species that were elevated in the third trimester of women with PE. Furthermore, race and trimester of pregnancy were considerable sources of plasma lipidomic variation in women with obesity. Conclusions: First and second trimester individual plasma lipid species do not predict the development of PE in obese women. In the third trimester, PE patients have elevated levels of plasmalogens-a class of lipoprotein-associated phospholipids that have been implicated in the response to oxidative stress.

Robust and high-throughput lipidomic quantitation of human blood samples using flow injection analysis with tandem mass spectrometry for clinical use

Direct infusion of lipid extracts into the ion source of a mass spectrometer is a well-established method for lipid analysis. In most cases, nanofluidic devices are used for sample introduction. However, flow injection analysis (FIA) based on sample infusion from a chromatographic pump can offer a simple alternative to shotgun-based approaches. Here, we describe important modification of a method based on FIA and tandem mass spectrometry (MS/MS). We focus on minimizing contamination of the FIA/MS both to render the lipidomic platform more robust and to increase its capacity and applicability for long-sequence measurements required in clinical applications. Robust validation of the developed method confirms its suitability for lipid quantitation in human plasma analysis. Measurements of standard human plasma reference material (NIST SRM 1950) and a set of plasma samples collected from kidney cancer patients and from healthy volunteers yielded highly similar results between FIA-MS/MS and ultra-high-performance supercritical fluid chromatography (UHPSFC)/MS, thereby demonstrating that all modifications have practically no effect on the statistical output. Newly modified FIA-MS/MS allows for the quantitation of 141 lipid species in plasma (11 major lipid classes) within 5.7min. Finally, we tested the method in a clinical laboratory of the General University Hospital in Prague. In the clinical setting, the method capacity reached 257 samples/day. We also show similar performance of the classification models trained based on the results obtained in clinical settings and the analytical laboratory at the University of Pardubice. Together, these findings demonstrate the high potential of the modified FIA-MS/MS for application in clinical laboratories to measure plasma and serum lipid profiles.

Labelfree mapping and profiling of altered lipid homeostasis in the rat hippocampus after traumatic stress: Role of oxidative homeostasis

Oxidative and lipid homeostasis are altered by stress and trauma and post-traumatic stress disorder (PTSD) is associated with alterations to lipid species in plasma. Stress-induced alterations to lipid and oxidative homeostasis may exacerbate PTSD pathology, but few preclinical investigations of stress-induced lipidomic changes in the brain exist. Currently available techniques for the quantification of lipid species in biological samples require tissue extraction and are limited in their ability to retrieve spatial information. Raman imaging can overcome this limitation through the quantification of lipid species in situ in minimally processed tissue slices. Here, we utilized a predator exposure and psychosocial stress (PE/PSS) model of traumatic stress to standardize Raman imaging of lipid species in the hippocampus using LC-MS based lipidomics and these data were confirmed with qRT-PCR measures of mRNA expression of relevant enzymes and transporters. Electron Paramagnetic Resonance Spectroscopy (EPR) was used to measure free radical production and an MDA assay to measure oxidized polyunsaturated fatty acids. We observed that PE/PSS is associated with increased cholesterol, altered lipid concentrations, increased free radical production and reduced oxidized polyunsaturated fats (PUFAs) in the hippocampus (HPC), indicating shifts in lipid and oxidative homeostasis in the HPC after traumatic stress.

Integrative phosphatidylcholine metabolism through phospholipase A2 in rats with chronic kidney disease.

Dysregulation in lipid metabolism is the leading cause of chronic kidney disease (CKD) and also the important risk factors for high morbidity and mortality. Although lipid abnormalities were identified in CKD, integral metabolic pathways for specific individual lipid species remain to be clarified. We conducted ultra-high-performance liquid chromatography-high-definition mass spectrometry-based lipidomics and identified plasma lipid species and therapeutic effects of Rheum officinale in CKD rats. Adenine-induced CKD rats were administered Rheum officinale. Urine, blood and kidney tissues were collected for analyses. We showed that exogenous adenine consumption led to declining kidney function in rats. Compared with control rats, a panel of differential plasma lipid species in CKD rats was identified in both positive and negative ion modes. Among the 50 lipid species, phosphatidylcholine (PC), lysophosphatidylcholine (LysoPC) and lysophosphatidic acid (LysoPA) accounted for the largest number of identified metabolites. We revealed that six PCs had integral metabolic pathways, in which PC was hydrolysed into LysoPC, and then converted to LysoPA, which was associated with increased cytosolic phospholipase A2 protein expression in CKD rats. The lower levels of six PCs and their corresponding metabolites could discriminate CKD rats from control rats. Receiver operating characteristic curves showed that each individual lipid species had high values of area under curve, sensitivity and specificity. Administration of Rheum officinale significantly improved impaired kidney function and aberrant PC metabolism in CKD rats. Taken together, this study demonstrates that CKD leads to PC metabolism disorders and that the dysregulation of PC metabolism is involved in CKD pathology.

A Lipid Signature with Perturbed Triacylglycerol Co-Regulation, Identified from Targeted Lipidomics, Predicts Risk for Type 2 Diabetes and Mediates the Risk from Adiposity in Two Prospective Cohorts of Chinese Adults.

The roles of individual and co-regulated lipid molecular species in the development of type 2 diabetes (T2D) and mediation from metabolic risk factors remain unknown. We conducted profiling of 166 plasma lipid species in 2 nested case-control studies within 2 independent cohorts of Chinese adults, the Dongfeng-Tongji and the Jiangsu non-communicable disease cohorts. After 4.61 (0.15) and 7.57 (1.13) years' follow-up, 1039 and 520 eligible participants developed T2D in these 2 cohorts, respectively, and controls were 1:1 matched to cases by age and sex. We found 27 lipid species, including 10 novel ones, consistently associated with T2D risk in the 2 cohorts. Differential correlation network analysis revealed significant correlations of triacylglycerol (TAG) 50:3, containing at least one oleyl chain, with 6 TAGs, at least 3 of which contain the palmitoyl chain, all downregulated within cases relative to controls among the 27 lipids in both cohorts, while the networks also both identified the oleyl chain-containing TAG 50:3 as the central hub. We further found that 13 of the 27 lipids consistently mediated the association between adiposity indicators (body mass index, waist circumference, and waist-to-height ratio) and diabetes risk in both cohorts (all P < 0.05; proportion mediated: 20.00%, 17.70%, and 17.71%, and 32.50%, 28.73%, and 33.86%, respectively). Our findings suggested notable perturbed co-regulation, inferred from differential correlation networks, between oleyl chain- and palmitoyl chain-containing TAGs before diabetes onset, with the oleyl chain-containing TAG 50:3 at the center, and provided novel etiological insight regarding lipid dysregulation in the progression from adiposity to overt T2D.

Effects of exercise on high-fat diet\u2013induced non-alcoholic fatty liver disease and lipid metabolism in ApoE knockout mice

BackgroundNon-alcoholic fatty liver disease (NAFLD), which is growing more common in the Western world, has become the main cause of chronic liver disease and is strongly associated with metabolism syndromes. NAFLD can indicate a wide spectrum of hepatic pathologies, ranging from simple hepatic steatosis and inflammatory non-alcoholic steatohepatitis to more severe stages of fibrosis and cirrhosis. Moreover, evidence has demonstrated that physical inactivity and westernized dietary habits may facilitate the development of NAFLD. Lipid modulation and metabolism could be important factors in the development of steatosis. Lipid species, characterized using a lipidomic approach with untargeted analysis, could provide potential biomarkers for the pathogenesis of NAFLD or therapeutic applications. Thus, in this study, the effects of exercise on the improvement of NAFLD were further investigated from a lipidomic perspective through the aspects of lipid regulation and metabolism.MethodsWild type (WT) C57BL/6 J and C57BL/6-ApoEem1Narl/Narl mice were assigned to one of four groups: WT mice fed a normal chow diet (CD), apolipoprotein E (ApoE) knockout mice fed a normal CD, ApoE knockout mice fed a high-fat diet (HFD), and ApoE knockout mice fed a HFD and provided with swimming exercise. The treatments (e.g., normal diet, HFD, and exercise) were provided for 12 consecutive weeks before the growth curves, biochemistry, fat composition, pathological syndromes, and lipid profiles were determined.ResultsExercise significantly reduced the HFD-induced obesity (weight and fat composition), adipocyte hypertrophy, liver lipid accumulation, and pathological steatosis. In addition, exercise ameliorated HFD-induced steatosis in the process of NAFLD. The lipidomic analysis revealed that the changes in plasma triglyceride (14:0/16:0/22:2), phosphatidic acid (18:0/17:2), and phosphatidylglycerol (16:0/20:2) induced by the administration of the HFD could be reversed significantly by exercise.ConclusionsThe 12-week regular exercise intervention significantly alleviated HFD-induced NAFLD through modulation of specific lipid species in plasma. This finding could elucidate the lipids effects behind the hepatic pathogenesis with exercise.

APOE ε2 resilience for Alzheimer's disease is mediated by plasma lipid species: Analysis of three independent cohort studies.

The apolipoprotein E (APOE) genotype is the strongest genetic risk factor for late-onset Alzheimer's disease. However, its effect on lipid metabolic pathways, and their mediating effect on disease risk, is poorly understood. We performed lipidomic analysis on three independent cohorts (the Australian Imaging, Biomarkers and Lifestyle [AIBL] flagship study, n=1087; the Alzheimer's Disease Neuroimaging Initiative [ADNI] 1 study, n=819; and the Busselton Health Study [BHS], n=4384), and we defined associations between APOE ε2 and ε4 and 569 plasma/serum lipid species. Mediation analysis defined the proportion of the treatment effect of the APOE genotype mediated by plasma/serum lipid species. A total of 237 and 104 lipid species were associated with APOE ε2 and ε4, respectively. Of these 68 (ε2) and 24 (ε4) were associated with prevalent Alzheimer's disease. Individual lipid species or lipidomic models of APOE genotypes mediated up to 30% and 10% of APOE ε2 and ε4 treatment effect, respectively. Plasma lipid species mediate the treatment effect of APOE genotypes on Alzheimer's disease and as such represent a potential therapeutic target.

Lipidomics reveals significant alterations associated with exclusive enteral nutrition treatment in adult patients with active Crohn's disease.

Crohn's disease (CD), a type of inflammatory bowel disease, is a chronic idiopathic disorder of the gastrointestinal tract with an increasing global incidence. Exclusive enteral nutrition (EEN) is a diet therapy that is effective in the management of active CD with unknown etiology. Lipid metabolism plays an important role in CD and may be associated with EEN treatment. This study compared the plasma lipid profiles before and after EEN in adults with active CD to those of healthy controls (HCs). Eleven adult patients with active CD who received enteral nutrition formula treatment for 12 weeks were included, along with 17 HCs. The profiles of 869 plasma lipid species were measured, and inflammatory and nutrition-associated indices were evaluated in the patients. Nine patients achieved clinical remission following 12 weeks of EEN treatment, and four achieved mucosal healing. Before EEN, 80 lipid species and 17 lipid classes were significantly different between patients with CD and HCs. After EEN treatment, 103 lipid species and 12 lipid classes were significantly different between patients with CD and HCs. Significant changes in 7 lipid classes and 38 lipid species were observed between the pre- vs. post-treatment CD patients. The levels of simplified glucosylceramide series, monogalactosyldiacylglycerol, phosphatidylinositol, phosphatidylserine, and phosphatidylcholine increased, while those of phosphatidylglycerol and phosphatidylinositol diphosphate decreased significantly after EEN. These lipid classes and species were associated with the inflammatory and nutritional indices. Pathway analysis suggested the metabolism of arachidonic acid, glycerophospholipids, linoleate, and phosphatidylinositol phosphate was related to the EEN mechanism. EEN induces alterations in multiple lipid classes and species, leading to clinical improvements. Lipid metabolism may be involved in the EEN anti-inflammatory effect.

High-dose triglyceride DHA supplementation increases plasma and cerebrospinal fluid phospholipid DHA species.

It is not clear whether triglyceride DHA-based formulations (TG-DHA) can sufficiently enrich brain DHA. Animal studies suggest that phosphatidylcholine (PC) and lyso-phosphatidylcholine (LPC) lipids might be preferred brain DHA substrates. The goal of this study is to assess the effect of high-dose TG-DHA supplementation on DHA-containing PC (PC-DHA) and LPC (LPC-DHA) lipid species in plasma and total cerebrospinal fluid (CSF) DHA as a surrogate for brain DHA incorporation. We conducted a randomized clinical trial stratified by DHA treatment (n=14) and placebo (n=14) status in non-demented older participants (CDR ≤ 0.5, age ³ 55 years old). Participants were provided 2,040 mg DHA daily in the form of TG-DHA for six months. Plasma and CSF were obtained at baseline and after supplementation. Participants were also stratified by ApoE ε4 status, an allele known to increase Alzheimer's disease (AD) risk. PC and LPC lipid species from plasma and CSF were isolated and examined by LC/MS-MS. Total fatty acids in CSF were measured via GC/MS-MS. Among all participants, PC-DHA represented 39% of total DHA in plasma, while LPC-DHA represented 1.8% of total DHA. PC-DHA increased by 69% and 19% in plasma and CSF, respectively, following supplementation compared to placebo (p<0.0001 for both). Plasma LPC-DHA increased by 140% in the treatment group compared to placebo (p<0.0001). Increases in plasma PC-DHA and LPC-DHA were both significantly correlated to changes in total DHA in CSF (R=0.8 and 0.57, respectively, p<0.003 for both). A trend toward greater increases in PC-DHA in non-ApoE ε4 carriers compared to carriers were also observed. Our data indicate that high-dose TG-DHA supplementation effectively increases DHA phospholipid incorporation in plasma and CSF. We acknowledge that CSF may not exactly reflect brain lipid uptake but provides useful information on brain DHA bioavailability. Our findings support that high-dose TG DHA supplementation are brain penetrant and can help answer whether enriching brain DHA can slow down cognitive decline in patients at risk of AD.

Lipidomic signatures for APOE genotypes provides new insights about mechanisms of resilience in Alzheimer’s disease

AbstractBackgroundThe apolipoprotein E gene (APOE) genotype is the first and strongest genetic risk factor for late‐onset Alzheimer’s disease and has emerged as a novel therapeutic target for AD. The encoded protein (Apolipoprotein E, APOE) is well‐known to be involved in lipoprotein transport and metabolism, but its effect on lipid metabolic pathways and the potential mediating effect of these on disease risk have not been fully defined.MethodWe performed lipidomic analysis on three independent cohorts (AIBL, n = 693; ADNI, n=207; BHS, n=4,384) and defined the association between APOE polymorphisms (ε4 and ε2) and plasma lipid species. To identify associations independent of lipoprotein metabolism, the analyses was performed with adjustment for clinical lipids (total cholesterol, HDL‐C and triglycerides). Causal mediation analysis was performed to estimate the proportion of risk in the outcome model explained by a direct effect of APOE genotype on prevalent AD — the average direct effect (ADE) — and the proportion that was mediated by lipid species or lipidomic risk models — the average causal mediation effect (ACME).ResultWe identified multiple associations of species from lipid classes such as ceramide, hexosylceramide, sphingomyelin, plasmalogens, alkyldiacylglycerol and cholesteryl esters with APOE polymorphisms (ε4 and ε2) that were independent of clinical lipoprotein measurements. There were 104 and 237 lipid species associated with APOE ε4 and ε2 respectively which were largely discordant. Of these 116 were also associated with Alzheimer’s disease. Individual lipid species (notably the alkyldiacylglycerol subspecies) or lipidomic risk models of APOE genotypes mediated up to 10% and 30% of APOE ε4 and ε2 treatment effect on AD risks respectively.ConclusionWe demonstrate a strong relationship between APOE polymorphisms and peripheral lipid species. Lipids species mediate a proportion of the effects of APOE genotypes in risk of AD, particularly resilience with e2. Our results highlight the involvement of lipids in how APOE e2 mediates its resilience to AD and solidify their involvement with the disease pathway.

Quantitative global lipidomics analysis of patients with ovarian cancer versus benign adnexal mass

Altered lipid metabolism has emerged as an important feature of ovarian cancer (OC), yet the translational potential of lipid metabolites to aid in diagnosis and triage remains unproven. We conducted a multi-level interrogation of lipid metabolic phenotypes in patients with adnexal masses, integrating quantitative lipidomics profiling of plasma and ascites with publicly-available tumor transcriptome data. Using Sciex Lipidyzer, we assessed concentrations of > 500 plasma lipids in two patient cohorts—(i) a pilot set of 100 women with OC (50) or benign tumor (50), and (ii) an independent set of 118 women with malignant (60) or benign (58) adnexal mass. 249 lipid species and several lipid classes were significantly reduced in cases versus controls in both cohorts (FDR < 0.05). 23 metabolites—triacylglycerols, phosphatidylcholines, cholesterol esters—were validated at Bonferroni significance (P < 9.16 × 10–5). Certain lipids exhibited greater alterations in early- (diacylglycerols) or late-stage (lysophospholipids) cases, and multiple lipids in plasma and ascites were positively correlated. Lipoprotein receptor gene expression differed markedly in OC versus benign tumors. Importantly, several plasma lipid species, such as DAG(16:1/18:1), improved the accuracy of CA125 in differentiating early-stage OC cases from benign controls, and conferred a 15–20% increase in specificity at 90% sensitivity in multivariate models adjusted for age and BMI. This study provides novel insight into systemic and local lipid metabolic differences between OC and benign disease, further implicating altered lipid uptake in OC biology, and advancing plasma lipid metabolites as a complementary class of circulating biomarkers for OC diagnosis and triage.

Retention dependences support highly confident identification of lipid species in human plasma by reversed-phase UHPLC/MS.

Reversed-phase ultrahigh-performance liquid chromatography-mass spectrometry (RP-UHPLC/MS) method was developed with the aim to unambiguously identify a large number of lipid species from multiple lipid classes in human plasma. The optimized RP-UHPLC/MS method employed the C18 column with sub-2-μm particles with the total run time of 25 min. The chromatographic resolution was investigated with 42 standards from 18 lipid classes. The UHPLC system was coupled to high-resolution quadrupole-time-of-flight (QTOF) mass analyzer using electrospray ionization (ESI) measuring full-scan and tandem mass spectra (MS/MS) in positive- and negative-ion modes with high mass accuracy. Our identification approach was based on m/z values measured with mass accuracy within 5 ppm tolerance in the full-scan mode, characteristic fragment ions in MS/MS, and regularity in chromatographic retention dependences for individual lipid species, which provides the highest level of confidence for reported identifications of lipid species including regioisomeric and other isobaric forms. The graphs of dependences of retention times on the carbon number or on the number of double bond(s) in fatty acyl chains were constructed to support the identification of lipid species in homologous lipid series. Our list of identified lipid species is also compared with previous publications investigating human blood samples by various MS-based approaches. In total, we have reported more than 500 lipid species representing 26 polar and nonpolar lipid classes detected in NIST Standard reference material 1950 human plasma.

1151-P: Differential Associations between Plasma Lipids and Insulin Resistance in Women with and without Type 1 Diabetes

People with type 1 diabetes (T1D) can have significant insulin resistance (IR), increasing risk for cardiovascular disease and mortality. Associations between circulating lipids and IR have been demonstrated; whether these associations differ in people with and without T1D is not well understood. We analyzed targeted plasma lipidomics in 30 premenopausal women aged 18-45 years (15 with T1D and 15 without diabetes [non-DM]) who underwent a hyperinsulinemic euglycemic clamp to measure glucose infusion rate (GIR). After stratifying by diabetes status, women were classified by tertiles of GIR, and moderated t-tests were used to compare lipids in the least IR vs. most IR tertile. Ceramide (Cer) 18:0, sphingomylelin (SM) 24:3 and SM 18:0 were higher in the most IR tertile in both groups (Table). However, 4 lipids (2 Cer, 1 SM, and 1 dihyrdoceramide [DHCer]) were higher in the most IR tertile in non-DM women, but were not significantly different in women with T1D. Eleven lipids (1 SM, 1 Cer, 1 DHCer, 1 lactosylceramide, and 7 1,2-diacylglycerols) were higher in the most IR tertile in women with T1D, but were not significantly different in non-DM women. Plasma lipid species were differentially associated with IR in women with and without T1D. Future work is needed to validate these findings in a larger sample of women and men, and to understand how these biomarkers relate to IR and lipid metabolism in T1D.View largeDownload slideView largeDownload slide DisclosureL. Pyle: None. T. B. Vigers: None. I. E. Schauer: None. B. C. Bergman: Consultant; Spouse/Partner; AstraZeneca, Eli Lilly and Company, Janssen Pharmaceuticals, Inc., Merck & Co., Inc., Novo Nordisk. J. K. Snell-bergeon: Stock/Shareholder; Self; GlaxoSmithKline plc.FundingAmerican Diabetes Association (7-13-CD-10 to J.K.S-B.); National Heart, Lung, and Blood Institute (R01HL61753, HL79611, HL113029); JDRF (17-2013-313) University of Colorado Diabetes & Endocrinology Research Center (P30DK57516); National Institutes of Health (M01-RR00051)

Plasma Lipidomic Profiles and Risk of Diabetes: 2 Prospective Cohorts of HIV-Infected and HIV-Uninfected Individuals.

Antiretroviral therapy (ART) use is associated with disrupted lipid and glucose metabolism in people with HIV infection. We aimed to identify plasma lipid species associated with risk of diabetes in the context of HIV infection. We profiled 211 plasma lipid species in 491 HIV-infected and 203 HIV-uninfected participants aged 35 to 55 years from the Women's Interagency HIV Study and the Multicenter AIDS Cohort Study. Cox proportional hazards model was used to examine associations between baseline lipid species and incident diabetes (166 diabetes cases were identified during a median follow-up of 12.6 years). We identified 11 lipid species, representing independent signals for 8 lipid classes/subclasses, associated with risk of diabetes (P < 0.05 after FDR correction). After adjustment for multiple covariates, cholesteryl ester (CE) (22:4), lysophosphatidylcholine (LPC) (18:2), phosphatidylcholine (PC) (36:4), phosphatidylcholine plasmalogen (34:3), and phosphatidylethanolamine (PE) (38:2) were associated with decreased risk of diabetes (HRs = 0.70 to 0.82 per SD increment), while diacylglycerol (32:0), LPC (14:0), PC (38:3), PE (36:1), and triacylglycerol (50:1) were associated with increased risk of diabetes (HRs = 1.26 to 1.56 per SD increment). HIV serostatus did not modify any lipid-diabetes associations; however, most of these lipid species were positively associated with HIV and/or ART use, including 3 diabetes-decreased ( CE [22:4], LPC [18:2], PE [38:2]) and all 5 diabetes-increased lipid species. This study identified multiple plasma lipid species associated with incident diabetes. Regardless of the directions of their associations with diabetes, most diabetes-associated lipid species were elevated in ART-treated people with HIV infection. This suggests a complex role of lipids in the link between ART and diabetes in HIV infection.

The plasma lipidome of the Quaker parrot (Myiopsitta monachus).

Dyslipidemias and lipid-accumulation disorders are common in captive parrots, in particular in Quaker parrots. Currently available diagnostic tests only measure a fraction of blood lipids and have overall problematic cross-species applicability. Comprehensively analyzing lipids in the plasma of parrots is the first step to better understand their lipid metabolism in health and disease, as well as to explore new lipid biomarkers. The plasma lipidome of 12 Quaker parrots was investigated using UHPLC-MS/MS with both targeted and untargeted methods. Targeted methods on 6 replicates measured 432 lipids comprised of sterol, cholesterol ester, bile acid, fatty acid, acylcarnitine, glycerolipid, glycerophospholipid, and sphingolipid panels. For untargeted lipidomics, precursor ion mass-to-charge ratios were matched to corresponding lipids using the LIPIDMAPS structure database and LipidBlast at the sum composition or acyl species level of information. Sterol lipids and glycerophospholipids constituted the majority of plasma lipids on a molar basis. The most common lipids detected with the targeted methods included free cholesterol, CE(18:2), CE(20:4) for sterol lipids; PC(36:2), PC(34:2), PC(34:1) for glycerophospholipids; TG(52:3), TG(54:4), TG(54:5), TG(52:2) for glycerolipids; SM(d18:1/16:0) for sphingolipids; and palmitic acid for fatty acyls. Over a thousand different lipid species were detected by untargeted lipidomics. Sex differences in the plasma lipidome were observed using heatmaps, principal component analysis, and discriminant analysis. This report presents the first comprehensive database of plasma lipid species in psittacine birds and paves the way for further research into blood lipid diagnostics and the impact of diet, diseases, and drugs on the parrot plasma lipidome.

Insights into the prognosis of lipidomic dysregulation for death risk in patients with coronary artery disease.

BackgroundDyslipidaemia contributes to the progression of coronary artery disease (CAD) toward adverse outcomes. Plasma lipidomic measure may improve the prognostic performances of clinical endpoints of CAD. Our research is designed to identify the correlations between plasma lipid species and the risks of death, major adverse cardiovascular event (MACE) and left ventricular (LV) remodeling in patients with CAD.MethodsA total of 1569 Chinese patients with CAD, 1011 single‐centre patients as internal training cohort, and 558 multicentre patients as external validation cohort, were enrolled. The concentration of plasma lipids in both cohorts was determined through widely targeted lipidomic profiling. Least absolute shrinkage and selection operator Cox and multivariate Cox regressions were used to develop prognostic models for death and MACE, respectively.ResultsTen (Cer(d18:1/20:1), Cer(d18:1/24:1), PE(30:2), PE(32:0), PE(32:2), PC(O‐38:2), PC(O‐36:4), PC(16:1/22:2), LPC(18:2/0:0) and LPE(0:0/24:6)) and two (Cer(d18:1/20:1) and LPC(20:0/0:0)) lipid species were independently related to death and MACE, respectively. Cer(d18:1/20:1) and Cer(d18:1/24:1) were correlated with LV remodeling (P < .05). The lipidic panel incorporating 10 lipid species and two traditional biomarkers for predicting 5‐year death risk represented a remarkable higher discrimination than traditional model with increased area under the curve from 76.56 to 83.65%, continuous NRI of 0.634 and IDI of 0.131. Furthermore, the panel was successfully used in differentiating multicentre patients with low, middle, or high risks (P < .0001). Further analysis indicated that the number of double bonds of phosphatidyl choline and the content of carbon atoms of phosphatidyl ethanolamines were negatively associated with death risk.ConclusionsImprovement in the prediction of death confirms the effectiveness of plasma lipids as predictors to risk classification in patients with CAD. The association between the structural characteristics of long‐chain polyunsaturated fatty acids and death risk highlights the need for mechanistic research that characterizes the role of individual lipid species in disease pathogenesis.

Identification of plasma lipid species as promising diagnostic markers for prostate cancer

BackgroundProstate cancer is a very common and highly fatal in men. Current non-invasive detection methods like serum biomarker are unsatisfactory. Biomarkers with high accuracy for diagnostic of prostate cancer are urgently needed. Many lipid species have been found related to various cancers. The purpose of our study is to explore the diagnostic value of lipids for prostate cancer.ResultsUsing triple quadruple liquid chromatography electrospray ionization tandem mass spectrometry, we performed lipidomics profiling of 367 lipids on a total 114 plasma samples from 30 patients with prostate cancer, 38 patients with benign prostatic hyperplasia (BPH), and 46 male healthy controls to evaluate the lipids as potential biomarkers in the diagnosis of prostate cancer. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway database was used to construct the potential mechanism pathway. After statistical analysis, five lipids were identified as a panel of potential biomarkers for the detection of prostate cancer between prostate cancer group and the BPH group; the sensitivity, specificity, and area under curve (AUC) of the combination of these five lipids were 73.3, 81.6%, and 0.800, respectively. We also identified another panel of five lipids in distinguishing between prostate cancer group and the control group with predictive values of sensitivity at 76.7%, specificity at 80.4%, and AUC at 0.836, respectively. The glycerophospholipid metabolism pathway of the selected lipids was considered as the target pathway.ConclusionsOur study indicated that the identified plasma lipid biomarkers have potential in the diagnosis of prostate cancer.

Relationships Between Plasma Lipids Species, Gender, Risk Factors, and Alzheimer's Disease.

Background:Lipid metabolism is altered in Alzheimer’s disease (AD); however, the relationship between AD risk factors (age, APOE ɛ4, and gender) and lipid metabolism is not well defined.Objective:We investigated whether altered lipid metabolism associated with increased age, gender, and APOE status may contribute to the development of AD by examining these risk factors in healthy controls and also clinically diagnosed AD individuals.Methods:We performed plasma lipidomic profiling (582 lipid species) of the Australian Imaging, Biomarkers and Lifestyle flagship study of aging cohort (AIBL) using liquid chromatography-mass spectrometry. Linear regression and interaction analysis were used to explore the relationship between risk factors and plasma lipid species.Results:We observed strong associations between plasma lipid species with gender and increasing age in cognitively normal individuals. However, APOE ɛ4 was relatively weakly associated with plasma lipid species. Interaction analysis identified differential associations of sphingolipids and polyunsaturated fatty acid esterified lipid species with AD based on age and gender, respectively. These data indicate that the risk associated with age, gender, and APOE ɛ4 may, in part, be mediated by changes in lipid metabolism.Conclusion:This study extends our existing knowledge of the relationship between the lipidome and AD and highlights the complexity of the relationships between lipid metabolism and AD at different ages and between men and women. This has important implications for how we assess AD risk and also for potential therapeutic strategies involving modulation of lipid metabolic pathways.

ANGPTL3 deficiency alters the lipid profile and metabolism of cultured hepatocytes and human lipoproteins

Loss-of-function (LOF) mutations in ANGPTL3, an inhibitor of lipoprotein lipase (LPL), cause a drastic reduction of serum lipoproteins and protect against the development of atherosclerotic cardiovascular disease. Therefore, ANGPTL3 is a promising therapy target. We characterized the impacts of ANGPTL3 depletion on the immortalized human hepatocyte (IHH) transcriptome, lipidome and human plasma lipoprotein lipidome. The transcriptome of ANGPTL3 knock-down (KD) cells showed altered expression of several pathways related to lipid metabolism. Accordingly, ANGPTL3 depleted IHH displayed changes in cellular overall fatty acid (FA) composition and in the lipid species composition of several lipid classes, characterized by abundant n-6 and n-3 polyunsaturated FAs (PUFAs). This PUFA increase coincided with an elevation of lipid mediators, among which there were species relevant for resolution of inflammation, protection from lipotoxic and hypoxia-induced ER stress, hepatic steatosis and insulin resistance or for the recovery from cardiovascular events. Cholesterol esters were markedly reduced in ANGPTL3 KD IHH, coinciding with suppression of the SOAT1 mRNA and protein. ANGPTL3 LOF caused alterations in plasma lipoprotein FA and lipid species composition. All lipoprotein fractions of the ANGPTL3 LOF subjects displayed a marked drop of 18:2n-6, while several highly unsaturated triacylglycerol (TAG) species were enriched. The present work reveals distinct impacts of ANGPTL3 depletion on the hepatocellular lipidome, transcriptome and lipid mediators, as well as on the lipidome of lipoproteins isolated from plasma of ANGPTL3-deficient human subjects. It is important to consider these lipidomics and transcriptomics findings when targeting ANGPTL3 for therapy and translating it to the human context.