An eicosanoid-centric view of atherothrombotic risk factors

Red Blood Cells' Omega-6 and Omega-3 Polyunsaturated Fatty Acids Have a Distinct Influence on LDL Particle Size and its Structural Modifications

BACKGROUND

While Omega-3 and omega-6 polyunsaturated fatty acids (n-3 and n-6 PUFAs) have established effects on cardiovascular disease (CVD) risk factors, little is known about their impacts on LDL quality markers.

OBJECTIVE

To assess the associations of n-3 and n-6 PUFA within red blood cells (RBC) with LDL particle size, small dense LDL-c (sdLDL-c), and electronegative LDL [LDL(-)] in adults with CVD risk factors.

METHODS

Cross-sectional study involving 335 men and women aged 30 to 74 with at least one cardiovascular risk factor. Analyses were conducted on biochemical parameters, such as glucose, insulin, HbA1c, C-reactive protein (CRP), lipid profile, lipoprotein subfractions, electronegative LDL particle [LDL(-)] and its autoantibody, and RBC n-3 and n-6 PUFAs. Independent t-test/Mann-Whitney test, one-way ANOVA/Kruskal-Wallis test, and multiple linear regressions were applied. All tests were two-sided, and a p-value of less than 0.05 was considered statistically significant.

RESULTS

The RBC n-6/n-3 ratio was associated with increased LDL(-) (β = 4.064; 95% CI = 1.381 - 6.748) and sdLDL-c (β = 1.905; 95% CI = 0.863 - 2.947) levels, and reduced LDL particle size (β = -1.032; 95% CI = -1.585 - -0.478). Separately, n-6 and n-3 PUFAs had opposing associations with those parameters, reinforcing the protective effects of n-3 and showing the potential negative effects of n-6 on LDL particle quality.

CONCLUSION

RBC n-6 PUFA was associated with increased cardiometabolic risk and atherogenicity of LDL particles, while n-3 PUFA was associated with better cardiometabolic parameters and LDL particle quality.

Arachidonic acid: reconciling the dichotomy of its oxidative cascade through specific deuteration

A new approach to attenuating pathological inflammatory reactions by buffering the eicosanoid pathways with oxidation-resistant hexadeuterated arachidonic acid (D-ARA) is discussed. Enzymatic processing of ARA, released by phospholipase A2, by lipoxygenases, cyclooxygenases, and cytochromes yields a wide range of bioactive eicosanoids, including pro-inflammation, pro-angiogenesis and pro-thrombosis species that, when produced in excess, are an underlying cause of pathology. Conversely, some products of ARA oxidation possess pro-resolving properties. Non-enzymatic free radical oxidation of ARA generates another large group of products such as isoprostanes and their metabolites, associated with inflammation, ischemia-reperfusion stress, and atherosclerosis. A separate group comprises reactive carbonyl derivatives that irreversibly damage diverse biomolecules. Being resistant to both enzymatic and non-enzymatic oxidation pathways due to large kinetic isotope effects, D-ARA may play a role in mitigating inflammation-related disorders and conditions, including inflammaging.

Clinical Potential of Hydrogen Sulfide in Peripheral Arterial Disease

Peripheral artery disease (PAD) affects more than 230 million people worldwide. PAD patients suffer from reduced quality of life and are at increased risk of vascular complications and all-cause mortality. Despite its prevalence, impact on quality of life and poor long-term clinical outcomes, PAD remains underdiagnosed and undertreated compared to myocardial infarction and stroke. PAD is due to a combination of macrovascular atherosclerosis and calcification, combined with microvascular rarefaction, leading to chronic peripheral ischemia. Novel therapies are needed to address the increasing incidence of PAD and its difficult long-term pharmacological and surgical management. The cysteine-derived gasotransmitter hydrogen sulfide (H₂S) has interesting vasorelaxant, cytoprotective, antioxidant and anti-inflammatory properties. In this review, we describe the current understanding of PAD pathophysiology and the remarkable benefits of H₂S against atherosclerosis, inflammation, vascular calcification, and other vasculo-protective effects.

Ability of a Polyphenol-Rich Nutraceutical to Reduce Central Nervous System Lipid Peroxidation by Analysis of Oxylipins in Urine: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

Isoprostanes (IsoPs) are lipid peroxidation biomarkers that reveal the oxidative status of the organism without specifying which organs or tissues it occurs in. Similar compounds have recently been identified that can assess central nervous system (CNS) lipid peroxidation status, usually oxidated by reactive oxygen species. These compounds are the neuroprostanes (NeuroPs) derived from eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and the F2t-dihomo-isoprotanes derived from adrenic acid (AdA). The aim of the present investigation was to evaluate whether the long-term nutraceutical consumption of high polyphenolic contents (600 mg) from fruits (such as berries) and vegetables shows efficacy against CNS lipid peroxidation in urine biomarkers. A total of 92 subjects (47 females, 45 males, age 34 ± 11 years old, weight 73.10 ± 14.29 kg, height 1.72 ± 9 cm, body mass index (BMI) 24.40 ± 3.43 kg/m2) completed a randomized, cross-over, double-blind study after an intervention of two periods of 16 weeks consuming either extract (EXT) or placebo (PLA) separated by a 4-week washout period. The results showed significant reductions in three AdA-derived metabolites, namely, 17-epi-17-F2t-dihomo-IsoPs (Δ −1.65 ng/mL; p < 0.001), 17-F2t-dihomo-IsoPs (Δ −0.17 ng/mL; p < 0.015), and ent-7(RS)-7-F2t-dihomo-IsoPs (Δ −1.97 ng/mL; p < 0.001), and one DHA-derived metabolite, namely, 4-F4t-NeuroP (Δ −7.94 ng/mL; p < 0.001), after EXT consumption, which was not observed after PLA consumption. These data seem to show the effectiveness of the extract for preventing CNS lipid peroxidation, as determined by measurements of oxylipins in urine through Ultra-High-Performance Liquid Chromatography triple quadrupole tandem mass spectrometry (UHPLC-QqQ-ESI-MS/MS).

Sex-Specific Response of the Brain Free Oxylipin Profile to Soluble Epoxide Hydrolase Inhibition

Oxylipins are the oxidation products of polyunsaturated fatty acids and have been implicated in neurodegenerative disorders, including dementia. Soluble epoxide hydrolase (sEH) converts epoxy-fatty acids to their corresponding diols, is found in the brain, and its inhibition is a treatment target for dementia. In this study, male and female C57Bl/6J mice were treated with an sEH inhibitor (sEHI), trans-4-[4-(3-adamantan-1-yl-ureido)-cyclohexyloxy]-benzoic acid (t-AUCB), for 12 weeks to comprehensively study the effect of sEH inhibition on the brain oxylipin profile, and modulation by sex. Ultra-high-performance liquid chromatography-tandem mass spectrometry was used to measure the profile of 53 free oxylipins in the brain. More oxylipins were modified by the inhibitor in males than in females (19 versus 3, respectively) and favored a more neuroprotective profile. Most were downstream of lipoxygenase and cytochrome p450 in males, and cyclooxygenase and lipoxygenase in females. The inhibitor-associated oxylipin changes were unrelated to serum insulin, glucose, cholesterol, or female estrous cycle. The inhibitor affected behavior and cognitive function as measured by open field and Y-maze tests in males, but not females. These findings are novel and important to our understanding of sexual dimorphism in the brain's response to sEHI and may help inform sex-specific treatment targets.

Oxylipin status, before and after LC n-3 PUFA supplementation, has little relationship with skeletal muscle biology in older adults at risk of sarcopenia

INTRODUCTION

Oxylipins form endogenously via the oxygenation of long-chain polyunsaturated fatty acids (LC PUFA). Several oxylipins are highly bioactive molecules and are believed to be key mediators of LC PUFA metabolism in the body. However, little is known in relation to whether oxylipins mediate alterations in skeletal muscle mass and function. The objective of this study was to determine if a relationship exists between the oxylipin profile and skeletal muscle biology in healthy older adults at risk of sarcopenia and determine if this changes in response to LC n-3 PUFA supplementation.

MATERIALS AND METHODS

This exploratory study investigated the baseline correlations between LC n-3, n-6 and n-9 PUFA-derived oxylipins and markers of muscle biology. For this, the concentration of 79 free (i.e., non-esterified) oxylipins was quantified in human plasma by liquid chromatography-mass spectrometry (LC-MS) and retrospectively correlated to phenotypic outcomes obtained pre-intervention from the NUTRIMAL study (n = 49). After examining the baseline relationship, the potential effect of supplementation (LC n-3 PUFA or an isoenergetic control made of high-oleic sunflower and corn oil) was evaluated by correlating the change in oxylipins concentration and the change in markers of skeletal muscle biology. The relationship between oxylipins pre- and post-intervention and their parent PUFA were also examined.

RESULTS

At baseline, the hydroxy product of mead acid (n-9 PUFA), 5-HETrE, was negatively correlated to the phenotypic parameters appendicular lean mass index (ALMI) (p = 0.003, r=-0.41), skeletal muscle mass index (SMMI) (p = 0.001, r=-0.46), handgrip strength (HGS) (p<0.001, r = 0.48) and isometric knee extension (p<0.001, r=-0.48). Likewise, LC n-6 PUFA hydroxy‑PUFA were negatively correlated to HGS (i.e., 12-HETrE, p = 0.002, r=-0.42, and 5- and 11-HETE, p = 0.006, r=-0.47 and p<0.001, r=-0.50 respectively), single leg stand time (i.e., 12-HETrE, p = 0.006, r=-0.39 and 16-HETE, p = 0.002, r=-0.43), and five-time-sit-to-stand test (FTST) performance (16-HETE, p = 0.006, r = 0.39), and positively correlated to gait speed (i.e., 12-HETrE, p = 0.007, r = 0.38 and 16-HETE, p = 0.006, r = 0.39). LC n-3 PUFA supplementation increased eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) derived oxylipins and reduced n-6 PUFA derived oxylipins. Parameters of skeletal muscle mass and strength were not significantly altered in either LC n-3 PUFA or placebo groups. Changes in plasma oxylipins concentrations were closely related to changes in their parent PUFA, assessed in the erythrocyte membrane, but were not associated with any changes in skeletal muscle parameters.

DISCUSSION AND CONCLUSION

At baseline, the status n-9 (5-HETrE) and n-6 PUFA derivates [12-HETrE, and 5-, 11- and 16-HETE], but not n-3 PUFA derived oxylipins, were associated with poor skeletal muscle health parameters (i.e., mass and strength). However, these correlations were no longer present when correlating relative changes from pre to post timepoints. An independent cohort validation is needed to explore baseline correlations further. Further research is warranted to assess other biological mechanisms by which LC n-3 PUFA might affect muscle biology.

Smoking Affects the Post-Stroke Inflammatory Response of Lipid Mediators in a Gender-Related Manner

The main goal of our study was to determine the effect of cigarette smoking on selected derivatives of arachidonic acid, linoleic acid, DHA, and EPA, which may be markers of post-stroke inflammation. The eicosanoid profile was compared in both smoking and non-smoking patients, without division and with division into gender. In the group of non-smokers, we observed higher levels of the linolenic acid derivative (LA) 9S HODE (p ≤ 0.05) than in smokers. However, after dividing the results by sex, it turned out that the level of this derivative was higher in non-smoking women compared to smoking women (p ≤ 0.01) and did not differentiate the group of men. Similarly, the level of the arachidonic acid metabolite LTX A4 (p ≤ 0.05) differed only in the group of women. In this group, we also observed a decreased level of 15S HETE in smoking women, but it was statistically insignificant (p ≤ 0.08). On the other hand, the level of this derivative was statistically significantly higher in the group of non-smoking women compared to male non-smokers. The group of men was differentiated by two compounds: TXB2 and NPD1. Male smokers had an almost two-fold elevation of TXB2 (p ≤ 0.01) compared with non-smokers, and in this group, we also observed an increased level of NPD1 compared with male non-smokers. On the other hand, when comparing female non-smokers and male non-smokers, in addition to the difference in 15S HETE levels, we also observed elevated levels of TXB2 in the group of non-smokers. We also analyzed a number of statistically significant correlations between the analyzed groups. Generally, men and women smokers showed a much smaller amount of statistically significant correlations than non-smokers. We believe that this is related to the varying degrees of inflammation associated with acute ischemic stroke and post-stroke response. On the one hand, tobacco smoke inhibits the activity of enzymes responsible for the conversion of fatty acids, but on the other hand, it can cause the failure of the inflammatory system, which is also the body's defense mechanism. Smoking cigarettes is a factor that increases oxidative stress even before the occurrence of a stroke incident, and at the same time accelerates it and inhibits post-stroke repair mechanisms. This study highlights the effect of smoking on inflammation in both genders mediated by lipid mediators, which makes smoking cessation undeniable.

A high sucrose diet modifies brain oxylipins in a sex-dependent manner

BACKGROUND

Oxylipins have been implicated in many biological processes and diseases. Dysregulation of cerebral lipid homeostasis and altered lipid metabolites have been associated with the onset and progression of dementia. Although most dietary interventions have focused on modulation of dietary fats, the impact of a high sucrose diet on the brain oxylipin profile is unknown.

METHODS

Male and female C57BL/6J mice were fed a high sucrose diet (HSD, 34%) in comparison to a control low sucrose diet (LSD, 12%) for 12 weeks beginning at 20 weeks of age. The profile of 53 free oxylipins was then measured in brain by ultra-high performance liquid chromatography tandem mass spectrometry. Serum glucose and insulin were measured enzymatically. We first assessed whether there were any effects of the diet on the brain oxylipin profile, then assessed for sex differences.

RESULTS

There were no differences in fasting serum glucose between the sexes for mice fed a HSD or in fasting serum insulin levels for mice on either diet. The HSD altered the brain oxylipin profile in both sexes in distinctly different patterns: there was a reduction in three oxylipins (by 47-61%) and an increase in one oxylipin (16%) all downstream of lipoxygenase enzymes in males and a reduction in eight oxylipins (by 14-94%) mostly downstream of cyclooxygenase activity in females. 9-oxo-ODE and 6-trans-LTB4 were most influential in the separation of the oxylipin profiles by diet in male mice, whereas 5-HEPE and 12-HEPE were most influential in the separation by diet in female mice. Oxylipins 9‑hydroxy-eicosatetraenoic acid (HETE), 11-HETE, and 15-HETE were higher in the brains of females, regardless of diet.

CONCLUSION

A HSD substantially changes brain oxylipins in a distinctly sexually dimorphic manner. Results are discussed in terms of potential mechanisms and links to metabolic disease. Sex and diet effects on brain oxylipin composition may provide future targets for the management of neuroinflammatory diseases, such as dementia.

Dietary antioxidant intake is inversely associated with 2,3-dinor oxylipin metabolites, the major excreted oxylipins in overweight and obese subjects

Cardiometabolic disease risk factors, including obesity, insulin resistance, high blood pressure, and dyslipidemia, are associated with elevated oxidative stress biomarkers like oxylipins. Increased adiposity by itself induces various isomers of this oxidized lipid family, while dietary polyphenols show benefits in its regulation. Previously, we showed that specific co-abundant microorganisms characterized the gut microbiota of Colombians and associated differentially with diet, lifestyle, obesity, and cardiometabolic health status, which led us to hypothesize that urinary oxylipins would reflect the intensity of oxidative metabolism linked to gut microbiota dysbiosis. Thus, we selected a convenience sample of 105 participants (age: 40.2 ± 11.9 years, 47.6% women), grouped according to microbiota, cardiometabolic health status, and body mass index (BMI); and evaluated 33 urinary oxylipins by HPLC-QqQ-MS/MS (e.g., isoprostanes, prostaglandins, and metabolites), paired with anthropometry and blood chemistry information and dietary antioxidants estimated from a 24-h food recall. In general, oxylipins did not show differences among individuals who differed in gut microbiota. While the unmetabolized oxylipin levels were not associated with BMI, the total content of oxylipin metabolites was highest in obese and cardiometabolically abnormal subjects (e.g., insulin resistant), mainly by prostaglandin-D (2,3-dinor-11β-PGF_2α) and 15-F_2t-IsoPs (2,3-dinor-15-F_2t-IsoP and 2,3-dinor-15-epi-15-F_2t-IsoP) metabolites. The total polyphenol intake in this cohort was 1070 ± 627 mg/day. After adjusting for body weight, the polyphenol intake was significantly higher in lean than overweight and showed an inverse association with dinor-oxylipin levels in principal component analysis. These results suggest that the 2,3-dinor-oxylipins could be more specific biomarkers associated with BMI than their parent oxylipins and that are sensitive to be regulated by dietary antioxidants.

Anti-Inflammatory and Antioxidant Capacity of a Fruit and Vegetable-Based Nutraceutical Measured by Urinary Oxylipin Concentration in a Healthy Population: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

Oxylipins, lipid biomarkers of inflammation are considered the gold standard method to evaluate the inflammatory and antioxidant status. The aim of the present study was to investigate whether the administration of a polyphenolic extract shot in the form of a nutraceutical was able to reduce inflammation, measured in urine markers. Ninety-two participants (45 males, 47 females, age 34 ± 11 years, weight 73.10 ± 14.29 kg, height 1.72 ± 9 cm, BMI 24.40 ± 3.43 kg/m2) completed the study after an intervention of two 16-week periods consuming extract or placebo separated by a 4-week washout period. The results showed significant differences in terms of reduction of different pro-inflammatory oxylipins (15-keto-PGF2α (from 0.90 ± 0.25 ng/mL to 0.74 ± 0.19 ng/mL p < 0.05), ent-PGF2α (from 1.59 ± 0.37 ng/mL to 1.44 ± 0.32 ng/mL p < 0.05), 2,3-dinor-15-F2t-Isop) (from 1.17 ± 0.35 ng/mL to 1.02 ± 0.27 ng/mL p < 0.05), in total oxylipins count (from 8.03 ± 1.86 ng/mL to 7.25 ± 1.23 ng/mL p < 0.05), and increase in PGE2 (from 1.02 ± 0.38 ng/mL to 1.26 ± 0.38 ng/mL p < 0.05) which has an anti-inflammatory character, after extract consumption compared to placebo. The available data seem to indicate that long-term consumption of a nutraceutical with high polyphenol content improves inflammation and oxidation parameters measured in urine, through UHPLC-QqQ-ESI-MS/MS.

Genetic analyses of circulating PUFA-derived mediators identifies heritable dihydroxyeicosatrienoic acid species

Estimates of heritability are the first step in identifying a trait with substantial variation due to genetic factors. Large-scale genetic analyses can identify the DNA variants that influence the levels of circulating lipid species and the statistical technique Mendelian randomisation can use these DNA variants to address potential causality of these lipids in disease. We estimated the heritability of plasma eicosanoids, octadecanoids and docosanoids to identify those lipid species with substantial heritability. We analysed plasma lipid mediators in 31 White British families (196 participants) ascertained for high blood pressure and deeply clinically and biochemically phenotyped over a 25-year period. We found that the dihydroxyeicosatrienoic acid (DHET) species, 11,12-DHET and 14,15-DHET, products of arachidonic acid metabolism by cytochrome P450 (CYP) monooxygenase and soluble epoxide hydrolase (sEH), exhibited substantial heritability (h2 = 33%-37%; Padj<0.05). Identification of these two heritable bioactive lipid species allows for future large-scale, targeted, lipidomics-genomics analyses to address causality in cardiovascular and other diseases.

A Review of Metabolomic Profiling in Rheumatoid Arthritis: Bringing New Insights in Disease Pathogenesis, Treatment and Comorbidities

Metabolomic analysis provides a wealth of information that can be predictive of distinctive phenotypes of pathogenic processes and has been applied to better understand disease development. Rheumatoid arthritis (RA) is an autoimmune disease with the establishment of chronic synovial inflammation that affects joints and peripheral tissues such as skeletal muscle and bone. There is a lack of useful disease biomarkers to track disease activity, drug response and follow-up in RA. In this review, we describe potential metabolic biomarkers that might be helpful in the study of RA pathogenesis, drug response and risk of comorbidities. TMAO (choline and trimethylamine oxide) and TCA (tricarboxylic acid) cycle products have been suggested to modulate metabolic profiles during the early stages of RA and are present systemically, which is a relevant characteristic for biomarkers. Moreover, the analysis of lipids such as cholesterol, FFAs and PUFAs may provide important information before disease onset to predict disease activity and treatment response. Regarding therapeutics, TNF inhibitors may increase the levels of tryptophan, valine, lysine, creatinine and alanine, whereas JAK/STAT inhibitors may modulate exclusively fatty acids. These observations indicate that different disease modifying antirheumatic drugs have specific metabolic profiles and can reveal differences between responders and non-responders. In terms of comorbidities, physical impairment represented by higher fatigue scores and muscle wasting has been associated with an increase in urea cycle, FFAs, tocopherols and BCAAs. In conclusion, synovial fluid, blood and urine samples from RA patients seem to provide critical information about the metabolic profile related to drug response, disease activity and comorbidities.

Oxylipin regulation by phenolic compounds from coffee beverage: Positive outcomes from a randomized controlled trial in healthy adults and macrophage derived foam cells

Oxylipins are considered biomarkers related to cardiovascular diseases (CVDs). They are generated in vivo via the oxygenation of polyunsaturated fatty acids as a result of oxidative stress and inflammation. Oxylipins are involved in vascular functions and are produced during foam cell formation in atherogenesis. Additionally, the consumption coffee is associated with the regulation on a particular oxylipin group, the F_2t-isoprostanes (F_2t-IsoPs). This function has been attributed to the chlorogenic acids (CGAs) from the coffee beverage. Considering the anti-inflammatory and antioxidant properties of CGAs, we evaluated the effects of two types of coffee that provided 787 mg CGAs/day (Coffee A) and 407 mg CGAs/day (Coffee B) by reducing 35 selected oxylipins in healthy subjects. Furthermore, we assessed the effect of CGAs on the cellular proatherogenic response in foam cells by using an oxidized LDL (oxLDL)-macrophage interaction model. After eight weeks of coffee consumption, the contents of 12 urine oxylipins were reduced. However, the effect of Coffee A showed a stronger decrease in IsoPs, dihomo-IsoPs, prostaglandins (PGs) and PG metabolites, probably due to its higher content of CGAs. Neither of the two coffees reduced the levels of oxLDL. Moreover, the in vitro oxylipin induction by oxLDL on foam cells was ameliorated by phenolic acids and CGAs, including the inhibition of IsoPs and PGs by caffeoylquinic and dicaffeoylquinic acids, respectively, while the phenolic acids maintained both antioxidant and anti-inflammatory activities. These findings suggest that coffee antioxidants are strong regulators of oxylipins related to CVDs. The clinical trial was registered on the International Clinical Trials Registry Platform, WHO primary registry (RPCEC00000168).

Desaturase Activity and the Risk of Type 2 Diabetes and Coronary Artery Disease: A Mendelian Randomization Study

Estimated Δ5-desaturase (D5D) and Δ6-desaturase (D6D) are key enzymes in metabolism of polyunsaturated fatty acids (PUFA) and have been associated with cardiometabolic risk; however, causality needs to be clarified. We applied two-sample Mendelian randomization (MR) approach using a representative sub-cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam Study and public data from DIAbetes Genetics Replication And Meta-analysis (DIAGRAM) and Coronary ARtery DIsease Genome wide Replication and Meta-analysis (CARDIoGRAM) genome-wide association studies (GWAS). Furthermore, we addressed confounding by linkage disequilibrium (LD) as all instruments from FADS1 (encoding D5D) are in LD with FADS2 (encoding D6D) variants. Our univariable MRs revealed risk-increasing total effects of both, D6D and D5D on type 2 diabetes (T2DM) risk; and risk-increasing total effect of D6D on risk of coronary artery disease (CAD). The multivariable MR approach could not unambiguously allocate a direct causal effect to either of the individual desaturases. Our results suggest that D6D is causally linked to cardiometabolic risk, which is likely due to downstream production of fatty acids and products resulting from high D6D activity. For D5D, we found indication for causal effects on T2DM and CAD, which could, however, still be confounded by LD.

Dietary fats and cardiometabolic disease: mechanisms and effects on risk factors and outcomes

The effect of dietary fats on cardiometabolic diseases, including cardiovascular diseases and type 2 diabetes mellitus, has generated tremendous interest. Many earlier investigations focused on total fat and conventional fat classes (such as saturated and unsaturated fats) and their influence on a limited number of risk factors. However, dietary fats comprise heterogeneous molecules with diverse structures, and growing research in the past two decades supports correspondingly complex health effects of individual dietary fats. Moreover, health effects of dietary fats might be modified by additional factors, such as accompanying nutrients and food-processing methods, emphasizing the importance of the food sources. Accordingly, the rapidly increasing scientific findings on dietary fats and cardiometabolic diseases have generated debate among scientists, caused confusion for the general public and present challenges for translation into dietary advice and policies. This Review summarizes the evidence on the effects of different dietary fats and their food sources on cell function and on risk factors and clinical events of cardiometabolic diseases. The aim is not to provide an exhaustive review but rather to focus on the most important evidence from randomized controlled trials and prospective cohort studies and to highlight current areas of controversy and the most relevant future research directions for understanding how to improve the prevention and management of cardiometabolic diseases through optimization of dietary fat intake.

Impact of short-term exposure to fine particulate matter air pollution on urinary metabolome: A randomized, double-blind, crossover trial

BACKGROUND

Metabolomics is a novel tool to explore the biological mechanisms of the health effects of fine particulate matter (PM_2.5) air pollution. Very few studies have examined the urinary metabolomic changes associated with PM_2.5 exposure.

OBJECTIVE

To assess the alternation in urine metabolomics in response to short-term PM_2.5 exposure.

METHODS

We conducted a randomized, double-blind, crossover trial of 9-day real or sham indoor air purification among 45 healthy college students in Shanghai, China. Urine samples were collected immediately at the end of each intervention stage and were analyzed for metabolomics using ultrahigh performance liquid chromatography-mass spectrometry. Orthogonal partial least square-discriminant analysis and linear mixed effect models were used to examine metabolomic changes between interventional scenarios and their associations with continuous PM_2.5 exposure.

RESULTS

The time-weighted average personal PM_2.5 exposure in the real-purified scenario was 50% lower than in the sham-purified air scenario (28.3 μg/m³ VS 56.9 μg/m³). A total of 40 differentiated urinary metabolites at a false discovery rate <0.05 were identified for the effects of both intervention and continuous PM_2.5 exposure, including 16 lipids, 5 purine metabolites, 2 neurotransmitters, and 3 coenzymes.

CONCLUSIONS

This real-world randomized crossover trial demonstrated that short-term PM_2.5 exposure could result in significant changes in urinary metabolomic profile, which may further lead to perturbation in energy metabolism, oxidative stress and inflammation.

Role of oxylipins in cardiovascular diseases

Globally, cardiovascular diseases (CVDs) are the number one cause of mortality. Approximately 18 million people died from CVDs in 2015, representing more than 30% of all global deaths. New diagnostic tools and therapies are eagerly required to decrease the prevalence of CVDs related to mortality and/or risk factors leading to CVDs. Oxylipins are a group of metabolites, generated via oxygenation of polyunsaturated fatty acids that are involved in inflammation, immunity, and vascular functions, etc. Thus far, over 100 oxylipins have been identified, and have overlapping and interconnected roles. Important CVD pathologies such as hyperlipidemia, hypertension, thrombosis, hemostasis and diabetes have been linked to abnormal oxylipin signaling. Oxylipins represent a new era of risk markers and/or therapeutic targets in several diseases including CVDs. The role of many oxylipins in the progression or regression in CVD, however, is still not fully understood. An increased knowledge of the role of these oxygenated polyunsaturated fatty acids in cardiovascular dysfunctions or CVDs including hypertension could possibly lead to the development of biomarkers for the detection and their treatment in the future.

Curcumin-galactomannoside complex inhibits pathogenesis in Ox-LDL-challenged human peripheral blood mononuclear cells

Oxidised low-density lipoprotein (ox-LDL) is a pro-atherogenic molecule, which induces inflammatory response and contributes to the pathogenesis of vascular dysfunction to atherosclerosis. The aim of the present study was to explore the anti-inflammatory effect of a novel bioavailable formulation of curcumin as 'curcumagalactomannosides' (CGM) against ox-LDL-induced inflammatory responses in human peripheral blood mononuclear cells (hPBMCs). Curcumagalactomannosides was made from natural curcumin using the soluble dietary fibre (galactomannans) derived from fenugreek seeds (Trigonella foenumgracum) and the hPBMCs were isolated from healthy human volunteers. The cells were cultured in collagen-coated plates at 37 °C and grouped as Group I (Control), Group II (ox-LDL treated) and Group III (ox-LDL + CGM treated). Further analysis of inflammatory markers, reactive oxygen species and mRNA expression levels indicated significantly increased expressions of iNOS, TNF-α, IL-6 and VCAM-1 in ox-LDL-treated group along with the nuclear translocation of NF-κB. Other inflammatory markers such as LOX, PGE2, total COX and lipid peroxidation level were also found to be significantly (p < 0.05) increased upon ox-LDL treatment. The treatment with CGM on the other hand was found to down-regulate and reverse the ox-LDL-induced alterations indicating its potential anti-inflammatory effect on hPBMCs via. NF-κB signalling pathway.

Oxidized LDL triggers changes in oxidative stress and inflammatory biomarkers in human macrophages

Oxidized low-density lipoprotein (oxLDL) is a well-recognized proatherogenic particle that functions in atherosclerosis. In this study, we established conditions to generate human oxLDL, characterized according to the grade of lipid and protein oxidation, particle size and oxylipin content. The induction effect of the cellular proatherogenic response was assessed in foam cells by using an oxLDL-macrophage interaction model. Uptake of oxLDL, reactive oxygen species production and expression of oxLDL receptors (CD36, SR-A and LOX-1) were significantly increased in THP-1 macrophages. Analyses of 35 oxylipins revealed that isoprostanes (IsoP) and prostaglandins (PGs) derived from the oxidation of arachidonic, dihomo gamma-linolenic and eicosapentaenoic acids were strongly and significantly induced in macrophages stimulated with oxLDL. Importantly, the main metabolites responsible for the THP1-macrophage response to oxLDL exposure were the oxidative stress markers 5-epi-5-F_2t-IsoP, 15-E_1t-IsoP, 8-F_3t-IsoP and 15-keto-15-F_2t-IsoP as well as inflammatory markers PGDM, 17-trans-PGF_3α, and 11β-PGF_2α, all of which are reported here, for the first time, to function in the interaction of oxLDL with THP-1 macrophages. By contrast, a salvage pathway mediated by anti-inflammatory PGs (PGE₁ and 17-trans-PGF_3α) was also identified, suggesting a response to oxLDL-induced injury. In conclusion, when THP-1 macrophages were treated with oxLDL, a specific induction of biomarkers related to oxidative stress and inflammation was triggered. This work contributes to our understanding of initial atherogenic events mediated by oxLDL-macrophage interactions and helps to generate new approaches for their modulation.

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OxLDL has a potent impact on the oxylipin profiles in THP-1 human macrophages.

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OxLDL induces biomarkers of oxidation and inflammation in THP-1 human macrophages.

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Human Macrophages produce anti-inflammatory prostaglandins after oxLDL exposure.

New insights into the effects of onion consumption on lipid mediators using a diet-induced model of hypercholesterolemia

The levels and roles of lipid mediators can be modified in response to nutritional stimuli. The aim of this study was to investigate shifts in oxylipin and sphingolipid profiles stimulated by a hypercholesterolemic (HC) diet along with the modulating effects of onion introduced as an antioxidant functional ingredient characterized in the diet (HCO). Oxylipin and sphingolipid profiles were determined in plasma and tissues from Wistar rats using LC-MS/MS. Plasma ω-3 and ω-6 PUFA-derived oxylipins decreased in rats after 7 weeks of HC feeding, but did not evidence a further shift with HCO diet. Onion ingredient supplementation modulated the hepatic concentrations of prostaglandins and enhanced ω-3 oxylipins in the liver of HCO-fed rats relative to the HC group. The HC diet induced shifts in plasma sphingolipids, increasing sphingoid bases, dihydroceramides and ceramides, whilst the sphingomyelin, hexosylceramide and lactosylceramide families decreased. The HCO diet modified some HC diet-induced changes in sphingolipids in liver and spleen tissue. Onion supplementation effected changes in lipid mediator levels in diet-induced hypercholesterolemic Wistar rats. The potential of onion as regulator of pro-inflammatory mediators, and possible enhancer of pro-resolution pathways, warrants further study of the interaction of functional ingredients with bioactive lipid mediators and their potential impact on inflammation, oxidative stress and organ dysfunction.

Serum-Based Oxylipins Are Associated with Outcomes in Primary Prevention Implantable Cardioverter Defibrillator Patients

Introduction

Individuals with systolic heart failure are at risk of ventricular arrhythmias and all-cause mortality. Little is known regarding the mechanisms underlying these events. We sought to better understand if oxylipins, a diverse class of lipid metabolites derived from the oxidation of polyunsaturated fatty acids, were associated with these outcomes in recipients of primary prevention implantable cardioverter defibrillators (ICDs).

Methods

Among 479 individuals from the PROSE-ICD study, baseline serum were analyzed and quantitatively profiled for 35 known biologically relevant oxylipin metabolites. Associations with ICD shocks for ventricular arrhythmias and all-cause mortality were evaluated using Cox proportional hazards models.

Results

Six oxylipins, 17,18-DiHETE (HR = 0.83, 95% CI 0.70 to 0.99 per SD change in oxylipin level), 19,20-DiHDPA (HR = 0.79, 95% CI 0.63 to 0.98), 5,6-DiHETrE (HR = 0.73, 95% CI 0.58 to 0.91), 8,9-DiHETrE (HR = 0.76, 95% CI 0.62 to 0.95), 9,10-DiHOME (HR = 0.81, 95% CI 0.65 to 1.00), and PGF_1α (HR = 1.33, 95% CI 1.04 to 1.71) were associated with the risk of appropriate ICD shock after multivariate adjustment for clinical factors. Additionally, 4 oxylipin-to-precursor ratios, 15S-HEPE / FA (20:5-ω3), 17,18-DiHETE / FA (20:5-ω3), 19,20-DiHDPA / FA (20:5-ω3), and 5S-HEPE / FA (20:5-ω3) were positively associated with the risk of all-cause mortality.

Conclusion

In a prospective cohort of patients with primary prevention ICDs, we identified several novel oxylipin markers that were associated with appropriate shock and mortality using metabolic profiling techniques. These findings may provide new insight into the potential biologic pathways leading to adverse events in this patient population.

Oxylipid Profile of Low-Dose Aspirin Exposure: A Pharmacometabolomics Study

Background

While aspirin is a well‐established and generally effective anti‐platelet agent, considerable inter‐individual variation in drug response exists, for which mechanisms are not completely understood. Metabolomics allows for extensive measurement of small molecules in biological samples, enabling detailed mapping of pathways involved in drug response.

Methods and Results

We used a mass‐spectrometry‐based metabolomics platform to investigate the changes in the serum oxylipid metabolome induced by an aspirin intervention (14 days, 81 mg/day) in healthy subjects (n=156). We observed a global decrease in serum oxylipids in response to aspirin (25 metabolites decreased out of 30 measured) regardless of sex. This decrease was concomitant with a significant decrease in serum linoleic acid levels (−19%, P=1.3×10⁻⁵), one of the main precursors for oxylipid synthesis. Interestingly, several linoleic acid‐derived oxylipids were not significantly associated with arachidonic‐induced ex vivo platelet aggregation, a widely accepted marker of aspirin response, but were significantly correlated with platelet reactivity in response to collagen.

Conclusions

Together, these results suggest that linoleic acid‐derived oxylipids may contribute to the non‐COX1 mediated variability in response to aspirin. Pharmacometabolomics allowed for more comprehensive interrogation of mechanisms of action of low dose aspirin and of variation in aspirin response.

Aspirin and multiple sclerosis

Aspirin is widely used to lessen the risks of cardiovascular events. Some studies suggest that patients with multiple sclerosis have an increased risk for some cardiovascular events, for example, venous thromboembolism and perhaps ischemic strokes, raising the possibility that aspirin could lessen these increased risks in this population or subgroups (patients with limited mobility and/or antiphospholipid antibodies). However, aspirin causes a small increased risk of hemorrhagic stroke, which is a concern as it could potentially worsen a compromised blood-brain barrier. Aspirin has the potential to ameliorate the disease process in multiple sclerosis (for example, by limiting some components of inflammation), but aspirin also has the potential to inhibit mitochondrial complex I activity, which is already reduced in multiple sclerosis. In an experimental setting of a cerebral ischemic lesion, aspirin promoted the proliferation and/or differentiation of oligodendrocyte precursors, raising the possibility that aspirin could facilitate remyelination efforts in multiple sclerosis. Other actions by aspirin may lead to small improvements of some symptoms (for example, lessening fatigue). Here we consider potential benefits and risks of aspirin usage by patients with multiple sclerosis.

Metabolomics and partial least square discriminant analysis to predict history of myocardial infarction of self-claimed healthy subjects: validity and feasibility for clinical practice

Background

The dynamics of metabolomics in establishing a prediction model using partial least square discriminant analysis have enabled better disease diagnosis; with emphasis on early detection of diseases. We attempted to translate the metabolomics model to predict the health status of the Orang Asli community whom we have little information. The metabolite expressions of the healthy vs. diseased patients (cardiovascular) were compared. A metabotype model was developed and validated using partial least square discriminant analysis (PLSDA). Cardiovascular risks of the Orang Asli were predicted and confirmed by biochemistry profiles conducted concurrently.

Results

Fourteen (14) metabolites were determined as potential biomarkers for cardiovascular risks with receiver operating characteristic of more than 0.7. They include 15S-HETE (AUC = 0.997) and phosphorylcholine (AUC = 0.995). Seven Orang Asli were clustered with the patients’ group and may have ongoing cardiovascular risks and problems. This is supported by biochemistry tests results that showed abnormalities in cholesterol, triglyceride, HDL and LDL levels.

Conclusions

The disease prediction model based on metabolites is a useful diagnostic alternative as compared to the current single biomarker assays. The former is believed to be more cost effective since a single sample run is able to provide a more comprehensive disease profile, whilst the latter require different types of sampling tubes and blood volumes.

Electronic supplementary material

The online version of this article (doi:10.1186/s13336-015-0018-4) contains supplementary material, which is available to authorized users.

Does lumbar puncture at night prevent post-dural puncture headache?

OBJECTIVES

The aim of this study was to identify the patient-related risk factors for post-dural puncture headache with same standardized procedures.

MATERIALS AND METHODS

The inclusion criteria were patients (i) who underwent lumbar puncture for diagnostic purposes, (ii) with ≥10 years of age, and (iii) with no structural lesions that could cause headache from brain-computed tomography or magnetic resonance images. The primary endpoint for this study was post-dural-puncture headache as a dependent variable. The differences were analyzed with demographic and cerebrospinal fluid profiles as independent variables.

RESULTS

Four hundred and thirteen patients met the inclusion criteria for this study, and 36 patients developed post-dural puncture headache. Patients with post-dural puncture headache were younger, had lower body mass index, and had less diabetes and hypertension. In cerebrospinal fluid profile, the counts of white blood cell and protein, and cerebrospinal fluid pressure were lower in patients with post-dural puncture headache than those without post-dural puncture headache, but glucose ratio was higher. Interestingly, patients who underwent puncture at daytime developed more post-dural puncture headache than those who were performed puncture at nighttime. After adjusting the clinical variables, multiple logistic regression analysis showed that younger age, lower cerebrospinal fluid pressure, and puncture at daytime were independently significant variables for predicting post-dural puncture headache.

CONCLUSIONS

We confirmed the risk factor for post-dural puncture headache such as young age, and newly found that patients who underwent puncture at daytime developed more post-dural puncture headache than those who were performed puncture at nighttime.

Targeted analysis of omega-6-derived eicosanoids in human serum by SPE-LC-MS/MS for evaluation of coronary artery disease

A targeted approach has been applied to quantitative analysis of eicosanoids derived from omega-6 fatty acids in serum from individuals diagnosed with coronary artery disease (CAD). The target metabolites were series-2 prostaglandins, thromboxane B2, hydroxyeicosatetraenoic acids, and hydroxyoctadecadienoic acids. The method was based on SPELC-MS/MS in selected reaction monitoring mode for highly selective and sensitive determination of the target eicosanoids. The combination of SPE and LC-MS/MS involved the benefits from both direct analysis of serum without a step for protein precipitation and fully automation of the analysis. The method allowed comparison of omega-6-derived eicosanoids in serum from patients diagnosed with CAD and from control individuals. The effect of treatment with aspirin on the profile of the target compounds was evaluated through its incidence on the different pathways. Finally, the serum levels of the target metabolites in patients diagnosed with CAD were also statistically examined according to the severity of the coronary lesion stratified as stable angina, non-ST-elevation acute coronary syndrome, and acute myocardial infarction.

Stable isotopic internal standard correction for quantitative analysis of hydroxyeicosatetraenoic acids (HETEs) in serum by on-line SPE-LC-MS/MS in selected reaction monitoring mode

The influence of the inclusion of a stable isotopic labeled internal standard (SIL-IS) on the quantitative analysis of hydroxyeicosatetranoic acids (HETEs) in human serum is evaluated in this research. A solid-phase extraction-liquid chromatography-tandem mass spectrometry (SPE-LC-MS/MS) platform, one of the preferred approaches for targeted analysis of biofluids through the selected reaction monitoring (SRM) operational mode, was used to determine HETEs. These compounds were chosen as targeted metabolites because of their involvement in cardiovascular disease, cancer and osteoporosis. 15HETE-d8 was chosen as internal standard to evaluate matrix effects. Thus, the physico-chemical properties of the SIL-IS were the basis to evaluate the analytical features of the method for each metabolite through four calibration models. Two of the models were built with standard solutions at different concentration levels, but one of the calibration sets was spiked with an internal standard (IS). The other two models were built with the serum pool from osteoporotic patients, which was spiked at different concentrations with the target analytes. In this case, one of the serum calibration sets was also spiked with the IS. The study shows that the IS allowed noticeable correction of matrix effects for some HETE isomers at certain concentration levels, while accuracy was decreased at low concentration (15ng/mL) of them. Therefore, characterization of the method has been properly completed at different concentration levels.

Chemical Atherogenesis: Role of Endogenous and Exogenous Poisons in Disease Development

Chemical atherogenesis is an emerging field that describes how environmental pollutants and endogenous toxins perturb critical pathways that regulate lipid metabolism and inflammation, thus injuring cells found within the vessel wall. Despite growing awareness of the role of environmental pollutants in the development of cardiovascular disease, the field of chemical atherogenesis can broadly include both exogenous and endogenous poisons and the study of molecular, biochemical, and cellular pathways that become dysregulated during atherosclerosis. This integrated approach is logical because exogenous and endogenous toxins often share the same mechanism of toxicity. Chemical atherogenesis is a truly integrative discipline because it incorporates concepts from several different fields, including biochemistry, chemical biology, pharmacology, and toxicology. This review will provide an overview of this emerging research area, focusing on cellular and animal models of disease.

The emerging role of oxylipins in thrombosis and diabetes

The prevalence of cardiovascular disease (CVD), the leading cause of death in the US, is predicted to increase due to the shift in age of the general population and increase in CVD risk factors such as obesity and diabetes. New therapies are required to decrease the prevalence of CVD risk factors (obesity and diabetes) as well as reduce atherothrombosis, the major cause of CVD related mortality. Oxylipins, bioactive metabolites derived from the oxygenation of polyunsaturated fatty acids, play a role in the progression of CVD risk factors and thrombosis. Aspirin, a cyclooxygenase-1 inhibitor, decreases atherothrombotic associated mortality by 25%. These potent effects of aspirin have shown the utility of modulating oxylipin signaling pathways to decrease CVD mortality. The role of many oxylipins in the progression of CVD, however, is still uncertain or controversial. An increased understanding of the role oxylipins play in CVD risk factors and thrombosis could lead to new therapies to decrease the prevalence of CVD and its associated mortality.

Exploratory investigation reveals parallel alteration of plasma fatty acids and eicosanoids in coronary artery disease patients

Fatty acids and eicosanoids are two important classes of signaling lipid molecules involved in the pathogenesis of cardiovascular diseases. To investigate the physiological functions and interplay between fatty acids and eicosanoids in coronary artery disease (CAD) patients, we developed an analytical approach for parallel quantitative analysis of plasma fatty acids and eicosanoids, using gas chromatography-tandem mass spectrometry (GC-MS/MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). In this study, 26 fatty acids and 12 eicosanoids were confidently detected in 12 patients with confirmed coronary artery disease and 11 healthy subjects. Pattern recognition analysis (principal components analysis, orthogonal partial least-square discriminate analysis, and hierarchical clustering analysis) demonstrated that the plasma lipid profile of fatty acids and eicosanoids enabled robust discrimination of CAD patients versus healthy subjects. Significant differences in six fatty acids and five eicosanoids were noted among CAD patients and healthy subjects. The development of cardiovascular disease-induced metabolic change of fatty acids and eicosanoids, such as eicosapentaenoic acid, docosahexaenoic acid, arachidonic acid, hydroxyeicosatetraenoic acids and hydroxyoctadecadienoic acid, were consistent with previous isolated observations. Moderate-strong correlations between three plasma fatty acids and three eicosanoids from arachidonic acid metabolism were also observed. In brief, findings from this exploratory study offered a new insight on the roles of various bioactive lipid molecules in the development of coronary artery disease biomarkers.

Bioinformatics analysis of transcriptome dynamics during growth in angus cattle longissimus muscle

Transcriptome dynamics in the longissimus muscle (LM) of young Angus cattle were evaluated at 0, 60, 120, and 220 days from early-weaning. Bioinformatic analysis was performed using the dynamic impact approach (DIA) by means of Kyoto Encyclopedia of Genes and Genomes (KEGG) and Database for Annotation, Visualization and Integrated Discovery (DAVID) databases. Between 0 to 120 days (growing phase) most of the highly-impacted pathways (eg, ascorbate and aldarate metabolism, drug metabolism, cytochrome P450 and Retinol metabolism) were inhibited. The phase between 120 to 220 days (finishing phase) was characterized by the most striking differences with 3,784 differentially expressed genes (DEGs). Analysis of those DEGs revealed that the most impacted KEGG canonical pathway was glycosylphosphatidylinositol (GPI)-anchor biosynthesis, which was inhibited. Furthermore, inhibition of calpastatin and activation of tyrosine aminotransferase ubiquitination at 220 days promotes proteasomal degradation, while the concurrent activation of ribosomal proteins promotes protein synthesis. Therefore, the balance of these processes likely results in a steady-state of protein turnover during the finishing phase. Results underscore the importance of transcriptome dynamics in LM during growth.