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

Effects of dietary supplementation of fish oil plus vitamin D3 on gut microbiota and fecal metabolites, and their correlation with nonalcoholic fatty liver disease risk factors: a randomized controlled trial

We previously reported that fish oil plus vitamin D3 (FO + D) could ameliorate nonalcoholic fatty liver disease (NAFLD). However, it is unclear whether the beneficial effects of FO + D on NAFLD are associated with gut microbiota and fecal metabolites. In this study, we investigated the effects of dietary supplementation of FO + D on gut microbiota and fecal metabolites and their correlation with NAFLD risk factors. Methods: A total of 61 subjects were randomly divided into three groups: FO + D group (2.34 g day-1 of eicosatetraenoic acid (EPA) + docosahexaenoic acid (DHA) + 1680 IU vitamin D3), FO group (2.34 g day-1 of EPA + DHA), and corn oil (CO) group (1.70 g d-1 linoleic acid). Blood and fecal samples were collected at the baseline and day 90. Gut microbiota were analyzed through 16S rRNA PCR analysis, and fecal co-metabolites were determined via untargeted ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). Results: The relative abundance of Eubacterium (p = 0.03) and Lactobacillus (p = 0.05) increased, whereas that of Streptococcus (p = 0.02) and Dialister (p = 0.04) decreased in the FO + D group compared with the CO group. Besides, changes in tetracosahexaenoic acid (THA, C24:6 n-3) (p = 0.03) levels were significantly enhanced, whereas 8,9-DiHETrE levels (p < 0.05) were reduced in the FO + D group compared with the CO group. The changes in 1,25-dihydroxyvitamin D3 levels in the fecal samples were inversely associated with insulin resistance, which was determined using the homeostatic model assessment model (HOMA-IR, r = -0.29, p = 0.02), and changes in 8,9-DiHETrE levels were positively associated with adiponectin levels (r = -0.43, p < 0.05). Conclusion: The present results indicate that the beneficial effects of FO + D on NAFLD may be partially attributed to the impact on gut microbiota and fecal metabolites.

Metabolomics implicate eicosanoids in severe functional mitral regurgitation

AIMS

Secondary, or functional, mitral regurgitation (FMR) was recently recognized as a separate clinical entity, complicating heart failure with reduced ejection fraction (HFrEF) and entailing particularly poor outcome. Currently, there is a lack of targeted therapies for FMR due to the fact that pathomechanisms leading to FMR progression are incompletely understood. In this study, we sought to perform metabolomic profiling of HFrEF patients with severe FMR, comparing results to patients with no or mild FMR.

METHODS AND RESULTS

Targeted plasma metabolomics and untargeted eicosanoid analyses were performed in samples drawn from HFrEF patients (n = 80) on optimal guideline-directed medical therapy. Specifically, 17 eicosanoids and 188 metabolites were analysed. Forty-seven patients (58.8%) had severe FMR, and 33 patients (41.2%) had no or non-severe FMR. Comparison of eicosanoid levels between groups, accounting for age, body mass index, and sex, revealed significant up-regulation of six eicosanoids (11,12-EET, 13(R)-HODE, 12(S)-HETE, 8,9-DiHETrE, metPGJ2, and 20-HDoHE) in severe FMR patients. Metabolites did not differ significantly. In patients with severe FMR, but not in those without severe FMR, levels of 8,9-DiHETrE above a cut-off specified by receiver-operating characteristic analysis independently predicted all-cause mortality after a median follow-up of 43 [interquartile range 38, 48] months [hazard ratio 12.488 (95% confidence interval 3.835-40.666), P < 0.0001].

CONCLUSIONS

We report the up-regulation of various eicosanoids in patients with severe FMR, with 8,9-DiHETrE appearing to predict mortality. Our observations may serve as a nucleus for further investigations into the causes and consequences of metabolic derangements in this important valvular abnormality.

A Review of Oxylipins in Alzheimer's Disease and Related Dementias (ADRD): Potential Therapeutic Targets for the Modulation of Vascular Tone and Inflammation

There is now a convincing body of evidence from observational studies that the majority of modifiable Alzheimer's disease and related dementia (ADRD) risk factors are vascular in nature. In addition, the co-existence of cerebrovascular disease with AD is more common than AD alone, and conditions resulting in brain ischemia likely promote detrimental effects of AD pathology. Oxylipins are a class of bioactive lipid mediators derived from the oxidation of long-chain polyunsaturated fatty acids (PUFAs) which act as modulators of both vascular tone and inflammation. In vascular cognitive impairment (VCI), there is emerging evidence that oxylipins may have both protective and detrimental effects on brain structure, cognitive performance, and disease progression. In this review, we focus on oxylipin relationships with vascular and inflammatory risk factors in human studies and animal models pertinent to ADRD. In addition, we discuss future research directions with the potential to impact the trajectory of ADRD risk and disease progression.

Hemodialysis and erythrocyte epoxy fatty acids

Fatty acid products derived from cytochromes P450 (CYP) monooxygenase and lipoxygenase (LOX)/CYP ω/(ω-1)-hydroxylase pathways are a superclass of lipid mediators with potent bioactivities. Whether or not the chronic kidney disease (CKD) and hemodialysis treatments performed on end-stage renal disease (ESRD) patients affect RBC epoxy fatty acids profiles remains unknown. Measuring the products solely in plasma is suboptimal. Since such determinations invariably ignore red blood cells (RBCs) that make up 3 kg of the circulating blood. RBCs are potential reservoirs for epoxy fatty acids that regulate cardiovascular function. We studied 15 healthy persons and 15 ESRD patients undergoing regular hemodialysis treatments. We measured epoxides derived from CYP monooxygenase and metabolites derived from LOX/CYP ω/(ω-1)-hydroxylase pathways in RBCs by LC-MS/MS tandem mass spectrometry. Our data demonstrate that various CYP epoxides and LOX/CYP ω/(ω-1)-hydroxylase products are increased in RBCs of ESRD patients, compared to control subjects, including dihydroxyeicosatrienoic acids (DHETs), epoxyeicosatetraenoic acids (EEQs), dihydroxydocosapentaenoic acids (DiHDPAs), and hydroxyeicosatetraenoic acids (HETEs). Hemodialysis treatment did not affect the majority of those metabolites. Nevertheless, we detected more pronounced changes in free metabolite levels in RBCs after dialysis, as compared with the total RBC compartment. These findings indicate that free RBC eicosanoids should be considered more dynamic or vulnerable in CKD.

Oxylipin Profiling of Alzheimer's Disease in Nondiabetic and Type 2 Diabetic Elderly

Oxygenated lipids, called “oxylipins,” serve a variety of important signaling roles within the cell. Oxylipins have been linked to inflammation and vascular function, and blood patterns have been shown to differ in type 2 diabetes (T2D). Because these factors (inflammation, vascular function, diabetes) are also associated with Alzheimer’s disease (AD) risk, we set out to characterize the serum oxylipin profile in elderly and AD subjects to understand if there are shared patterns between AD and T2D. We obtained serum from 126 well-characterized, overnight-fasted elderly individuals who underwent a stringent cognitive evaluation and were determined to be cognitively healthy or AD. Because the oxylipin profile may also be influenced by T2D, we assessed nondiabetic and T2D subjects separately. Within nondiabetic individuals, cognitively healthy subjects had higher levels of the nitrolipid 10-nitrooleate (16.8% higher) compared to AD subjects. AD subjects had higher levels of all four dihydroxyeicosatrienoic acid (DiHETrE) species: 14,15-DiHETrE (18% higher), 11,12 DiHETrE (18% higher), 8,9-DiHETrE (23% higher), and 5,6-DiHETrE (15% higher). Within T2D participants, we observed elevations in 14,15-dihydroxyeicosa-5,8,11-trienoic acid (14,15-DiHETE; 66% higher), 17,18-dihydroxyeicosa-5,8,11,14-tetraenoic acid (17,18-DiHETE; 29% higher) and 17-hydroxy-4,7,10,13,15,19-docosahexaenoic acid (17-HDoHE; 105% higher) and summed fatty acid diols (85% higher) in subjects with AD compared to cognitively healthy elderly, with no differences in the DiHETrE species between groups. Although these effects were no longer significant following stringent adjustment for multiple comparisons, the consistent effects on groups of molecules with similar physiological roles, as well as clear differences in the AD-related profiles within nondiabetic and T2D individuals, warrant further research into these molecules in the context of AD.

Measurement of Serum and Hepatic Eicosanoids by Liquid Chromatography Tandem-Mass Spectrometry (LC-MS/MS) in a Mouse Model of Hepatocellular Carcinoma (HCC) with Delivery of c-Met and Activated β-Catenin by Hepatocyte Hydrodynamic Injection

BACKGROUND Most forms of cancer, including hepatocellular carcinoma (HCC), are associated with varying degrees of chronic inflammation. The association between the expression of eicosanoids, which are bioactive lipid mediators of inflammation, and HCC remains unknown. The aim of this study was to measure serum and hepatic eicosanoids in a mouse model of HCC with the delivery of c-Met and activated b-catenin by hepatocyte hydrodynamic injection. MATERIAL AND METHODS The HCC mouse model, and normal control mice, were used in this study with co-delivery of human c-Met combined with activated β-catenin into hepatocytes through hydrodynamic injection. Liquid chromatography tandem-mass spectrometry (LC-MS/MS) analysis was used to measure serum and hepatic eicosanoid levels. RESULTS The combined activation of c-Met and β-catenin was induced in the HCC mouse model. LC-MS/MS showed that a total of 13 eicosanoids in serum and 12 eicosanoids in liver tissue were significantly increased in the HCC mice, when compared with control mice. CONCLUSIONS In a mouse model of HCC, co-activation of the c-Met and β-catenin signaling pathway resulted in increased levels of serum and hepatic eicosanoids.

A metabolomics study of Qiliqiangxin in a rat model of heart failure: a reverse pharmacology approach

The Chinese medicine Qiliqiangxin (QL) has been shown to have a protective role in heart failure. Here, we explore the underlying working mechanism of the key therapeutic component in QL using a rat model of heart failure. Heart failure after myocardial infarction was induced surgically and confirmed using echocardiography; a separate group of rats underwent sham surgery. The rats with heart failure were randomly assigned to receive QL, the angiotensin-converting enzyme inhibitor benazepril, or placebo groups. Blood samples were collected from the rats at four time points for up to 8 weeks and used for biochemical analysis and mass spectrometry‒based metabolomics profiling. In total, we measured nine well-known biochemical parameters of heart failure and 147 metabolites. In the rats with heart failure, QL significantly improved these biochemical parameters and metabolomics profiles, significantly increasing the cardioprotective parameter angiopoietin-like 4 and significantly lowering inflammation-related oxylipins and lysophosphatidic acids compared to benazepril. Mechanistically, QL may improve outcome in heart failure by controlling inflammatory process and cardiac hypertrophy. Clinical studies should be designed in order to investigate these putative mechanisms in patients.

GM-CSF- and M-CSF-primed macrophages present similar resolving but distinct inflammatory lipid mediator signatures

M1 and M2 activated macrophages (Mϕs) have different roles in inflammation. Because pathogens may first encounter resting cells, we investigated lipid mediator profiles prior to full activation. Human monocytes were differentiated with granulocyte Mϕ colony-stimulating factor (GM-CSF) or Mϕ colony-stimulating factor (M-CSF), which are known to prime toward M1 or M2 phenotypes, respectively. Lipid mediators released during resting conditions and produced in response to bacterial stimuli (LPS/N-formylmethionyl-leucyl-phenylalanine or peptidoglycan) were quantified by liquid chromatography-mass spectrometry. In resting conditions, both Mϕ phenotypes released primarily proresolving lipid mediators (prostaglandin E₂ metabolite, lipoxin A₄, and 18-hydroxyeicosapentaenoic acid). A striking shift toward proinflammatory eicosanoids was observed when the same cells were exposed (30 min) to bacterial stimuli: M-CSF Mϕs produced considerably more 5-lipoxygenase products, particularly leukotriene C₄, potentially linked to M2 functions in asthma. Prostaglandins were formed by both Mϕ types. In the M-CSF cells, there was also an enhanced release of arachidonic acid and activation of cytosolic phospholipase A₂ However, GM-CSF cells expressed higher levels of 5-lipoxygenase and 5-lipoxygenase-activating protein, and in ionophore incubations these cells also produced the highest levels of 5-hydroxyeicosatetraenoic acid. In summary, GM-CSF and M-CSF Mϕs displayed similar proresolving lipid mediator formation in resting conditions but shifted toward different proinflammatory eicosanoids upon bacterial stimuli. This demonstrates that preference for specific eicosanoid pathways is primed by CSFs before full M1/M2 activation.-Lukic, A., Larssen, P., Fauland, A., Samuelsson, B., Wheelock, C. E., Gabrielsson, S., Radmark, O. GM-CSF- and M-CSF-primed macrophages present similar resolving but distinct inflammatory lipid mediator signatures.

Emerging role and recent applications of metabolomics biomarkers in obesity disease research

Metabolomics is a promising approach for the identification of metabolites which serve for early diagnosis, prediction of therapeutic response and prognosis of disease.