Ceramides as Emerging Players in Cardiovascular Disease: Focus on Their Pathogenetic Effects and Regulation by Diet

Impaired lipid metabolism is a pivotal driver of cardiovascular disease (CVD). In this regard, the accumulation of ceramides within the circulation as well as in metabolically active tissues and atherosclerotic plaques is a direct consequence of derailed lipid metabolism. Ceramides may be at the nexus between impaired lipid metabolism and CVD. Indeed, although on one hand ceramides have been implicated in the pathogenesis of CVD, on the other specific ceramide subspecies have also been proposed as predictors of major adverse cardiovascular events. This review will provide an updated overview of the role of ceramides in the pathogenesis of CVD, as well as their pathogenetic mechanisms of action. Furthermore, the manuscript will cover the importance of ceramides as biomarkers to predict cardiovascular events and the role of diet, both in terms of nutrients and dietary patterns, in modulating ceramide metabolism and homeostasis.

Differential Effects of n-3 and n-6 Polyunsaturated Fatty Acids on Placental and Embryonic Growth and Development in Diabetic Pregnant Mice

The present study aimed to investigate the differential effects of n-3 and n-6 polyunsaturated fatty acids (PUFAs) on placental and embryonic development. Pregnant mice were assigned to five groups: healthy control (HC), diabetes mellitus control (DMC), diabetes + low-dose n-3 PUFA (Ln-3), diabetes + high-dose n-3 PUFA (Hn-3), and diabetes + n-6 PUFA (n-6). On E12.5d, the Hn-3 group, but not the n-6 group, had a higher placenta weight. The weight ratio of embryo to placenta in the n-6 group was significantly lower than in the Hn-3 group but higher than in the DMC group. The Hn-3 group had significantly higher protein levels of VEGF, IGF-1, and IGFBP3, while the n-6 group had lower VEGF than the DMC group. Compared with the DMC group, embryonic Cer-16:0 was significantly higher in the Hn-3 group, while embryonic PC (36:6), PC (38:7), and PE (40:7) were significantly lower in the n-6 group. The embryo and placenta weights were positively correlated with placental VEGF, IGFBP3, and embryonic Cer-16:0, and they were negatively correlated with embryonic PC (36:6) and PE (40:7). The weight ratio of embryo to placenta was negatively correlated with embryonic PC (36:6). In addition, embryonic Cer-16:0 was positively correlated with placental VEGF and IGFBP3. In conclusion, n-3 PUFA and n-6 PUFA improved placental and embryonic growth through different mechanisms.

Docosahexaenoic Acid Modulates Nonalcoholic Fatty Liver Disease by Suppressing Endocannabinoid System

SCOPE

Endocannabinoid signaling regulates energy homeostasis, and is tightly associated with nonalcoholic fatty liver disease (NAFLD). The study previously finds that supplementation of docosahexaenoic acid (DHA) has superior function to ameliorate NAFLD compared with eicosapentaenoic acid (EPA), however, the underlying mechanism remains elusive. The present study aims to investigate whether DHA intervention alleviates NAFLD via endocannabinoid system.

METHODS AND RESULTS

In a case-control study, the serum endocannabinoid ligands in 60 NAFLD and 60 healthy subjects are measured. Meanwhile, NAFLD model is established in mice fed a high-fat and -cholesterol diet (HFD) for 9 weeks. DHA or EPA is administrated for additional 9 weeks. Serum primary endocannabinoid ligands, namely anandamide (AEA) and 2-arachidoniylglycerol (2-AG), are significantly higher in individuals with NAFLD compared with healthy controls. NAFLD model shows that serum 2-AG concentrations and adipocyte cannabinoid receptor 1 expression levels are significantly lower in DHA group compared with HFD group. Lipidomic and targeted ceramide analyses further confirm that endocannabinoid signaling inhibition has exerted deletion of hepatic C16:0-ceramide contents, resulting in down-regulation of de novo fatty acid synthesis and up-regulation of fatty acid β-oxidation related protein expression levels.

CONCLUSIONS

This work elucidates that DHA has improved NAFLD by suppressing endocannabinoid system.

n-3 polyunsaturated fatty acids in phospholipid or triacylglycerol form attenuate nonalcoholic fatty liver disease via mediating cannabinoid receptor 1/adiponectin/ceramide pathway

n-3 polyunsaturated fatty acids (PUFA) have shown to exert beneficial effects in the treatment of nonalcoholic fatty liver disease (NAFLD). Supplements of n-3 PUFA occur in either phospholipid or triacylglycerol form. The present study aimed to compare whether the different n-3 PUFA of marine-origin, namely krill oil, DHA/EPA-phospholipid (PL), and EPA/DHA-triacylglycerol (TAG) forms had differential abilities to ameliorate NAFLD. The NAFLD model was established in mice fed a high-fat and high-cholesterol diet (HFD). The mice showed evidence of weight gain, dyslipidemia, insulin resistance and hepatic steatosis after 9 weeks of HFD, while the three forms of the n-3 PUFA reduced hepatic TAG accumulation, fatty liver and improved insulin instance, and hepatic biomarkers after 9 weeks of intervention. Of these, krill oil intervention significantly reduced adipocyte hypertrophy and hepatic steatosis in comparison with DHA/EPA-PL and EPA/DHA-TAG groups. Importantly, only krill oil intervention significantly reduced serum alanine transaminase, aspartate transaminase concentrations and low-density lipoprotein-cholesterol, compared with the HFD group. Supplemental n-3 PUFA lowered circulating anandamide (AEA) and 2-arachidonoylglycerol (2-AG) concentrations, compared with the HFD group, which was associated with down-regulating CB1 and upregulating adiponectin expressions in adipose tissue. Besides, targeted lipidomic analyses indicated that the increased adiponectin levels were accompanied by reductions in hepatic ceramide levels. The reduced ceramide levels were associated with inhibiting lipid synthesis and increasing fatty acid β-oxidation, finally inhibiting TAG accumulation in the liver. Through mediating CB1/adiponectin/ceramide pathway, the present study suggested that administration of krill oil had superior health effects in the therapy of NAFLD in comparison with DHA/EPA-PL and EPA/DHA-TAG.

Elderly rats fed with a high-fat high-sucrose diet developed sex-dependent metabolic syndrome regardless of long-term metformin and liraglutide treatment

Aim/Introduction

The study aimed to determine the effectiveness of early antidiabetic therapy in reversing metabolic changes caused by high-fat and high-sucrose diet (HFHSD) in both sexes.

Methods

Elderly Sprague-Dawley rats, 45 weeks old, were randomized into four groups: a control group fed on the standard diet (STD), one group fed the HFHSD, and two groups fed the HFHSD along with long-term treatment of either metformin (HFHSD+M) or liraglutide (HFHSD+L). Antidiabetic treatment started 5 weeks after the introduction of the diet and lasted 13 weeks until the animals were 64 weeks old.

Results

Unexpectedly, HFHSD-fed animals did not gain weight but underwent significant metabolic changes. Both antidiabetic treatments produced sex-specific effects, but neither prevented the onset of prediabetes nor diabetes.

Conclusion

Liraglutide vested benefits to liver and skeletal muscle tissue in males but induced signs of insulin resistance in females.

How Does CBG Administration Affect Sphingolipid Deposition in the Liver of Insulin-Resistant Rats?

BACKGROUND

Cannabigerol (CBG), a non-psychotropic phytocannabinoid found in Cannabis sativa plants, has been the focus of recent studies due to its potential therapeutic properties. We proposed that by focusing on sphingolipid metabolism, which plays a critical role in insulin signaling and the development of insulin resistance, CBG may provide a novel therapeutic approach for metabolic disorders, particularly insulin resistance.

METHODS

In a rat model of insulin resistance induced by a high-fat, high-sucrose diet (HFHS), we aimed to elucidate the effect of intragastrically administered CBG on hepatic sphingolipid deposition and metabolism. Moreover, we also elucidated the expression of sphingolipid transporters and changes in the sphingolipid concentration in the plasma.

RESULTS

The results, surprisingly, showed a lack of changes in de novo ceramide synthesis pathway enzymes and significant enhancement in the expression of enzymes involved in ceramide catabolism, which was confirmed by changes in hepatic sphingomyelin, sphinganine, sphingosine-1-phosphate, and sphinganine-1-phosphate concentrations.

CONCLUSIONS

The results suggest that CBG treatment may modulate sphingolipid metabolism in the liver and plasma, potentially protecting the liver against the development of metabolic disorders such as insulin resistance.

Combined Intake of Fish Oil and D-Fagomine Prevents High-Fat High-Sucrose Diet-Induced Prediabetes by Modulating Lipotoxicity and Protein Carbonylation in the Kidney

Obesity has been recognized as a major risk factor for chronic kidney disease, insulin resistance being an early common metabolic feature in patients suffering from this syndrome. This study aims to investigate the mechanism underlying the induction of kidney dysfunction and the concomitant onset of insulin resistance by long-term high-fat and sucrose diet feeding in Sprague Dawley rats. To achieve this goal, our study analyzed renal carbonylated protein patterns, ectopic lipid accumulation and fatty acid profiles and correlated them with biometrical and biochemical measurements and other body redox status parameters. Rats fed the obesogenic diet developed a prediabetic state and incipient kidney dysfunction manifested in increased plasma urea concentration and superior levels of renal fat deposition and protein carbonylation. An obesogenic diet increased renal fat by preferentially promoting the accumulation of saturated fat, arachidonic, and docosahexaenoic fatty acids while decreasing oleic acid. Renal lipotoxicity was accompanied by selectively higher carbonylation of proteins involved in the blood pH regulation, i.e., bicarbonate reclamation and synthesis, amino acid, and glucose metabolisms, directly related to the onset of insulin resistance. This study also tested the combination of antioxidant properties of fish oil with the anti-diabetic properties of buckwheat D-Fagomine to counteract diet-induced renal alterations. Results demonstrated that bioactive compounds combined attenuated lipotoxicity, induced more favorable lipid profiles and counteracted the excessive carbonylation of proteins associated with pH regulation in the kidneys, resulting in an inhibition of the progression of the prediabetes state and kidney disease.

Nutrients, Physical Activity, and Mitochondrial Dysfunction in the Setting of Metabolic Syndrome

Metabolic syndrome (MetS) is a cluster of metabolic risk factors for diabetes, coronary heart disease, non-alcoholic fatty liver disease, and some tumors. It includes insulin resistance, visceral adiposity, hypertension, and dyslipidemia. MetS is primarily linked to lipotoxicity, with ectopic fat deposition from fat storage exhaustion, more than obesity per se. Excessive intake of long-chain saturated fatty acid and sugar closely relates to lipotoxicity and MetS through several pathways, including toll-like receptor 4 activation, peroxisome proliferator-activated receptor-gamma regulation (PPARγ), sphingolipids remodeling, and protein kinase C activation. These mechanisms prompt mitochondrial dysfunction, which plays a key role in disrupting the metabolism of fatty acids and proteins and in developing insulin resistance. By contrast, the intake of monounsaturated, polyunsaturated, and medium-chain saturated (low-dose) fatty acids, as well as plant-based proteins and whey protein, favors an improvement in sphingolipid composition and metabolic profile. Along with dietary modification, regular exercises including aerobic, resistance, or combined training can target sphingolipid metabolism and improve mitochondrial function and MetS components. This review aimed to summarize the main dietary and biochemical aspects related to the physiopathology of MetS and its implications for mitochondrial machinery while discussing the potential role of diet and exercise in counteracting this complex clustering of metabolic dysfunctions.

Maternal diets affected ceramides and fatty acids in brain regions of neonatal rats with prenatal ethanol exposure

Objectives: Ceramide (Cer), known as apoptotic markers, increases with prenatal ethanol (EtOH) exposure, resulting in neuroapoptosis. Whether maternal nutrition can impact Cer concentrations in brain, via altering plasma and brain fatty acid compositions have not been examined. This study compared a standard chow with a formulated semi-purified energy dense (E-dense) diet on fatty acid composition, Cer concentrations, and apoptosis in plasma and brain regions (cortex, cerebellum, and hippocampus) of pups exposed to EtOH during gestation. Methods: Pregnant Sprague-Dawley rats were randomized into four groups: chow (n = 6), chow + EtOH (20% v/v) (n = 7), E-dense (n = 6), and E-dense + EtOH (n = 8). At postnatal day 7, representing the peak brain growth spurt in rats, lipids, and apoptosis were analyzed by gas chromatography and a fluorometric caspase-3 assay kit, respectively. Results: Maternal E-dense diet increased total fatty acid concentrations (p < 0.0001), including docosahexaenoic acid (DHA) (p < 0.0001) in plasma, whereas DHA concentrations were decreased in the cerebellum (p < 0.03) of pups than those from chow-fed dams. EtOH-induced Cer elevations in the hippocampus of pups born to dams fed chow were reduced by an E-dense diet (p < 0.02). No significant effects of maternal diet quality and EtOH were observed on caspase-3 activity. No significant correlations existed between plasma/brain fatty acids and Cer concentrations. Discussions: Maternal diet quality affected fatty acid compositions and Cer concentrations of pups with prenatal EtOH exposure, differently. Maternal nutrition has the potential to prevent or alleviate some of the adverse effects of prenatal EtOH exposure.

Lipidomics profiling of biological aging in American Indians: the Strong Heart Family Study

Telomeres shorten with age and shorter leukocyte telomere length (LTL) has been associated with various age-related diseases. Thus, LTL has been considered a biomarker of biological aging. Dyslipidemia is an established risk factor for most age-related metabolic disorders. However, little is known about the relationship between LTL and dyslipidemia. Lipidomics is a new biochemical technique that can simultaneously identify and quantify hundreds to thousands of small molecular lipid species. In a large population comprising 1843 well-characterized American Indians in the Strong Heart Family Study, we examined the lipidomic profile of biological aging assessed by LTL. Briefly, LTL was quantified by qPCR. Fasting plasma lipids were quantified by untargeted liquid chromatography-mass spectrometry. Lipids associated with LTL were identified by elastic net modeling. Of 1542 molecular lipids identified (518 known, 1024 unknown), 174 lipids (36 knowns) were significantly associated with LTL, independent of chronological age, sex, BMI, hypertension, diabetes status, smoking status, bulk HDL-C, and LDL-C. These findings suggest that altered lipid metabolism is associated with biological aging and provide novel insights that may enhance our understanding of the relationship between dyslipidemia, biological aging, and age-related diseases in American Indians.

Omega-3 carboxylic acids and fenofibrate differentially alter plasma lipid mediators in patients with non-alcoholic fatty liver disease

Fibrates and omega-3 polyunsaturated acids are used for the treatment of hypertriglyceridemia but have not demonstrated consistent effects on cardiovascular (CV) risk. In this study, we investigate how these two pharmacological agents influence plasma levels of bioactive lipid mediators, aiming to explore their efficacy beyond that of lipid-lowering agents. Plasma from overweight patients with non-alcoholic fatty liver disease (NAFLD) and hypertriglyceridemia, participating in a randomized placebo-controlled study investigating the effects of 12 weeks treatment with fenofibrate or omega-3 free carboxylic acids (OM-3CA) (200 mg or 4 g per day, respectively), were analyzed for eicosanoids and related PUFA species, N-acylethanolamines (NAE) and ceramides. OM-3CA reduced plasma concentrations of proinflammatory PGE₂ , as well as PGE₁ , PGD₁ and thromboxane B2 but increased prostacyclin, and eicosapentaenoic acid- and docosahexaenoic acid-derived lipids of lipoxygenase and cytochrome P450 monooxygenase (CYP) (e.g., 17-HDHA, 18-HEPE, 19,20-DiHDPA). Fenofibrate reduced plasma concentrations of vasoactive CYP-derived eicosanoids (DHETs). Although OM-3CA increased plasma levels of the NAE docosahexaenoyl ethanolamine and docosapentaenoyl ethanolamine, and fenofibrate increased palmitoleoyl ethanolamine, the effect of both treatments may have been masked by the placebo (olive oil). Fenofibrate was more efficacious than OM-3CA in significantly reducing plasma ceramides, pro-inflammatory lipids associated with CV disease risk. Neither treatment affected putative lipid species associated with NAFLD. Our results show that OM-3CA and fenofibrate differentially modulate the plasma mediator lipidome, with OM-3CA promoting the formation of lipid mediators with potential effects on chronic inflammation, while fenofibrate mainly reducing ceramides. These findings suggest that both treatments could ameliorate chronic inflammation with possible impact on disease outcomes, independent of triglyceride reduction.

Neutral sphingomyelinase-2 and cardiometabolic diseases

Sphingolipids, in particular ceramides, play vital role in pathophysiological processes linked to metabolic syndrome, with implications in the development of insulin resistance, pancreatic ß-cell dysfunction, type 2 diabetes, atherosclerosis, inflammation, nonalcoholic steatohepatitis, and cancer. Ceramides are produced by the hydrolysis of sphingomyelin, catalyzed by different sphingomyelinases, including neutral sphingomyelinase 2 (nSMase2), whose dysregulation appears to underlie many of the inflammation-related pathologies. In this review, we discuss the current knowledge on the biochemistry of nSMase2 and ceramide production and its regulation by inflammatory cytokines, with particular reference to cardiometabolic diseases. nSMase2 contribution to pathogenic processes appears to involve cyclical feed-forward interaction with proinflammatory cytokines, such as TNF-α and IL-1ß, which activate nSMase2 and the production of ceramides, that in turn triggers the synthesis and release of inflammatory cytokines. We elaborate these pathogenic interactions at the molecular level and discuss the potential therapeutic benefits of inhibiting nSMase2 against inflammation-driven cardiometabolic diseases.

The impact of EPA and DHA on ceramide lipotoxicity in the metabolic syndrome

The metabolic syndrome (MetS) is a cluster of cardiovascular risk factors including obesity, insulin resistance (IR) and dyslipidaemia. Consumption of a high-fat diet (HFD) enriched in SFA leads to the accumulation of ceramide (Cer), the central molecule in sphingolipid metabolism. Elevations in plasma and tissue Cer are found in obese individuals, and there is evidence to suggest that Cer lipotoxicity contributes to the MetS. EPA and DHA have shown to improve MetS parameters including IR, inflammation and hypertriacylglycerolaemia; however, whether these improvements are related to Cer is currently unknown. This review examines the potential of EPA and DHA to improve Cer lipotoxicity and MetS parameters including IR, inflammation and dyslipidaemia in vitro and in vivo. Current evidence from cell culture and animal studies indicates that EPA and DHA attenuate palmitate- or HFD-induced Cer lipotoxicity and IR, whereas evidence in humans is greatly lacking. Overall, there is intriguing potential for EPA and DHA to improve Cer lipotoxicity and related MetS parameters, but more research is warranted.

The Effects of the Combination of Buckwheat D-Fagomine and Fish Omega-3 Fatty Acids on Oxidative Stress and Related Risk Factors in Pre-Obese Rats

The combined supplementation of buckwheat D-fagomine (FG) and fish omega-3 polyunsaturated fatty acids (ω-3 PUFA) attenuates the development of insulin resistance in rats fed a high-fat (HF) diet. This study aimed to examine the effects of combined supplementation with FG and ω-3 PUFA on dyslipidemia, transaminases, interleukin-6, and oxidative stress. Forty-five male Sprague-Dawley rats were fed a standard diet, an HF diet, an HF diet supplemented with FG, an HF diet supplemented with ω-3 PUFA, or an HF diet supplemented with FG and ω-3 PUFA for 21 weeks. Triacylglycerol, cholesterol, aspartate aminotransferase, alanine aminotransferase, and interleukin-6 were measured. The assessment of oxidative stress included plasma antioxidant capacity, antioxidant enzyme activities, glutathione content, lipid peroxidation, and protein carbonylation. The combined supplementation with FG and ω-3 PUFA did not attenuate the slight accumulation of liver cholesterol induced by the HF diet but normalized the plasma alanine aminotransferase activity. Rats fed the HF diet supplemented with the combination showed a lower amount of plasma interleukin-6 than those fed a standard diet. The combination attenuated oxidative damage induced by the HF diet, decreased antioxidant enzyme activities, and enhanced glutathione status. The beneficial effects of the combination of FG and ω-3 PUFA on oxidative stress and related risk factors in pre-obese rats were mainly modulated by ω-3 PUFA.

Ceramides improve atherosclerotic cardiovascular disease risk assessment beyond standard risk factors

Ceramides are bioactive lipids that act as secondary messengers for both intra- and inter-cellular signaling. Elevated plasma concentrations of ceramides are associated with multiple risk factors of atherosclerotic cardiovascular diseases and comorbidities including obesity, insulin resistance and diabetes mellitus. Furthermore, atherosclerotic plaques have been shown to be highly enriched with ceramides. Increases in ceramide content may accelerate atherosclerosis development by promoting LDL infiltration to the endothelium and aggregation within the intima of artery walls. Thus, ceramides appear to play a key role in the development of cardiometabolic disease due to their central location in major metabolic pathways that intersect lipid and glucose metabolism. Recently published data have shown that ceramides are not only of scientific interest but may also have diagnostic value. Their independent prognostic value for future cardiovascular outcomes over and above LDL cholesterol and other traditional risk factors have consistently been shown in numerous clinical studies. Thus, ceramide testing with a mass spectrometer offers a simple, reproducible and cost-effective blood test for risk stratification in atherosclerotic cardiovascular diseases.

Effects of Fish Oil and Grape Seed Extract Combination on Hepatic Endogenous Antioxidants and Bioactive Lipids in Diet-Induced Early Stages of Insulin Resistance in Rats

Diacylglycerols (DAG) and ceramides have been suggested as early predictors of insulin resistance. This study was aimed to examine the combined effects of fish oil (FO) and grape seed extract (GSE) on hepatic endogenous antioxidants, DAG and ceramides in diet-induced early stages of insulin resistance. Thirty-five rats were fed one of the following diets: (1) a standard diet (STD group), (2) a high-fat high-sucrose diet (HFHS group), (3) an HFHS diet enriched with FO (FO group), (4) an HFHS diet enriched with GSE (GSE group) or (5) an HFHS diet enriched with FO and GSE (FO + GSE group). In the liver, endogenous antioxidants were measured using spectrophotometric and fluorometric techniques, and non-targeted lipidomics was conducted for the assessment of DAG and ceramides. After 24 weeks, the FO + GSE group showed increased glutathione peroxidase activity, as well as monounsaturated fatty acid and polyunsaturated fatty acid-containing DAG, and long-chain fatty acid-containing ceramides abundances compared to the STD group. The FO and GSE combination induced similar activation of the antioxidant system and bioactive lipid accumulation in the liver than the HFHS diet without supplementation. In addition, the FO and GSE combination increased the abundances of polyunsaturated fatty acid-containing DAG in the liver.

Omega-3 polyunsaturated fatty acids impinge on CD4+ T cell motility and adipose tissue distribution via direct and lipid mediator-dependent effects

AIMS

Adaptive immunity contributes to the pathogenesis of cardiovascular metabolic disorders (CVMD). The omega-3 polyunsaturated fatty acids (n-3PUFA) are beneficial for cardiovascular health, with potential to improve the dysregulated adaptive immune responses associated with metabolic imbalance. We aimed to explore the mechanisms through which n-3PUFA may alter T cell motility and tissue distribution to promote a less inflammatory environment and improve lymphocyte function in CVMD.

METHODS AND RESULTS

Using mass spectrometry lipidomics, cellular, biochemical, and in vivo and ex vivo analyses, we investigated how eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), the main n-3PUFA, modify the trafficking patterns of activated CD4+ T cells. In mice subjected to allogeneic immunization, a 3-week n-3PUFA-enriched diet reduced the number of effector memory CD4+ T cells found in adipose tissue, and changed the profiles of eicosanoids, octadecanoids, docosanoids, endocannabinoids, 2-monoacylglycerols, N-acyl ethanolamines, and ceramides, in plasma, lymphoid organs, and fat tissues. These bioactive lipids exhibited differing chemotactic properties when tested in chemotaxis assays with activated CD4+ T cells in vitro. Furthermore, CD4+ T cells treated with EPA and DHA showed a significant reduction in chemokinesis, as assessed by trans-endothelial migration assays, and, when implanted in recipient mice, demonstrated less efficient migration to the inflamed peritoneum. Finally, EPA and DHA treatments reduced the number of polarized CD4+ T cells in vitro, altered the phospholipid composition of membrane microdomains and decreased the activity of small Rho GTPases, Rhoα, and Rac1 instrumental in cytoskeletal dynamics.

CONCLUSIONS

Our findings suggest that EPA and DHA affect the motility of CD4+ T cells and modify their ability to reach target tissues by interfering with the cytoskeletal rearrangements required for cell migration. This can explain, at least in part, the anti-inflammatory effects of n-3PUFA supporting their potential use in interventions aiming to address adipocyte low-grade inflammation associated with cardiovascular metabolic disease.

Modulation of the Liver Protein Carbonylome by the Combined Effect of Marine Omega-3 PUFAs and Grape Polyphenols Supplementation in Rats Fed an Obesogenic High Fat and High Sucrose Diet

Diet-induced obesity has been linked to metabolic disorders such as cardiovascular diseases andtype 2 diabetes. A factor linking diet to metabolic disorders is oxidative stress, which can damagebiomolecules, especially proteins. The present study was designed to investigate the effect of marineomega-3 polyunsaturated fatty acids (PUFAs) (eicosapentaenoic acid (EPA) and docosahexaenoic acid(DHA)) and their combination with grape seed polyphenols (GSE) on carbonyl-modified proteins fromplasma and liver in Wistar Kyoto rats fed an obesogenic diet, namely high-fat and high-sucrose (HFHS)diet. A proteomics approach consisting of fluorescein 5-thiosemicarbazide (FTSC) labelling of proteincarbonyls, visualization of FTSC-labelled protein on 1-DE or 2-DE gels, and protein identification byMS/MS was used for the protein oxidation assessment. Results showed the efficiency of the combinationof both bioactive compounds in decreasing the total protein carbonylation induced by HFHS diet in bothplasma and liver. The analysis of carbonylated protein targets, also referred to as the 'carbonylome',revealed an individual response of liver proteins to supplements and a modulatory effect on specificmetabolic pathways and processes due to, at least in part, the control exerted by the supplements on theliver protein carbonylome. This investigation highlights the additive effect of dietary fish oils and grapeseed polyphenols in modulating in vivo oxidative damage of proteins induced by the consumption ofHFHS diets.

Integration of lipidomics and metabolomics for in-depth understanding of cellular mechanism and disease progression

Mass spectrometry (MS)-based omics technologies are now widely used to profile small molecules in multiple matrices to confer comprehensive snapshots of cellular metabolic phenotypes. The metabolomes of cells, tissues, and organisms comprise a variety of molecules including lipids, amino acids, sugars, organic acids, and so on. Metabolomics mainly focus on the hydrophilic classes, while lipidomics has emerged as an independent omics owing to the complexities of the organismal lipidomes. The potential roles of lipids and small metabolites in disease pathogenesis have been widely investigated in various human diseases, but system-level understanding is largely lacking, which could be partly attributed to the insufficiency in terms of metabolite coverage and quantitation accuracy in current analytical technologies. While scientists are continuously striving to develop high-coverage omics approaches, integration of metabolomics and lipidomics is becoming an emerging approach to mechanistic investigation. Integration of metabolome and lipidome offers a complete atlas of the metabolic landscape, enabling comprehensive network analysis to identify critical metabolic drivers in disease pathology, facilitating the study of interconnection between lipids and other metabolites in disease progression. In this review, we summarize omics-based findings on the roles of lipids and metabolites in the pathogenesis of selected major diseases threatening public health. We also discuss the advantages of integrating lipidomics and metabolomics for in-depth understanding of molecular mechanism in disease pathogenesis.

Effect of High-Dose Marine Omega-3 Fatty Acids on Atherosclerosis: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

A recent randomized controlled trial (RCT), the Reduction of Cardiovascular Events with Icosapent Ethyl-Intervention Trial (REDUCE-IT), reported that high-dose marine omega-3 fatty acids (OM3) significantly reduce cardiovascular disease (CVD) outcomes, yet the mechanisms responsible for this benefit remain unknown. To test the hypothesis that high-dose OM3 is anti-atherosclerotic, we performed a systematic review and meta-analysis of RCT of high-dose OM3 on atherosclerosis. The protocol of this systematic review was registered with PROSPERO (CRD42019125566). PubMed, Embase, Cochran Central Register for Controlled Trials, and Clinicaltrials.gov databases were searched using the following criteria: adult participants, high-dose OM3 (defined as ≥3.0 g/day, or in Japan 1.8 g/day and purity ≥90%) as the intervention, changes in atherosclerosis as the outcome, and RCTs with an intervention duration of ≥6 months. A random-effects meta-analysis was used to pool estimates across studies. Among the 598 articles retrieved, six articles met our criteria. Four RCTs evaluated atherosclerosis in the coronary and two in the carotid arteries. High-dose OM3 significantly slowed the progression of atherosclerosis (standardized mean difference −1.97, 95% confidence interval −3.01, −0.94, p < 0.001). The results indicate that anti-atherosclerotic effect of high-dose OM3 is one potential mechanism in reducing CVD outcomes demonstrated in the REDUCE-IT trial.

Non-alcoholic fatty liver disease: Insights from sphingolipidomics

Non-alcoholic fatty liver disease (NAFLD) is a major clinical concern and its treatment consumes abundant resources. While accumulation of lipids in hepatocytes initiates the disease, this in itself is not necessarily harmful; rather, initiation of inflammation and subsequent fibrosis and cirrhosis are critical steps in NAFLD pathology. Mechanisms linking lipid overload to downstream disease progression are not fully understood; however, bioactive lipid metabolism may underlie instigation of proinflammatory signaling. With the advent of high-throughput, sensitive, and quantitative mass spectrometry-based methods for assessing lipid profiles in NAFLD, several trends have emerged, including that increases in specific sphingolipids correlate with the transition from the relatively benign condition of simple fatty liver to the much more concerning inflamed state. Continued studies that implement sphingolipid profiling will enable the extrapolations of candidate enzymes and pathways involved in NAFLD, either in biopsies or plasma from human samples, and also in animal models, from which data are much more abundant. While most data thus far are derived from targeted lipidomics approaches, unbiased, semi-quantitative approaches hold additional promise for furthering our understanding of sphingolipids as markers of and players in NAFLD.

Breast Milk Lipidome Is Associated with Early Growth Trajectory in Preterm Infants

Human milk is recommended for feeding preterm infants. The current pilot study aims to determine whether breast-milk lipidome had any impact on the early growth-pattern of preterm infants fed their own mother's milk. A prospective-monocentric-observational birth-cohort was established, enrolling 138 preterm infants, who received their own mother's breast-milk throughout hospital stay. All infants were ranked according to the change in weight Z-score between birth and hospital discharge. Then, we selected infants who experienced "slower" (n = 15, -1.54 ± 0.42 Z-score) or "faster" (n = 11, -0.48 ± 0.19 Z-score) growth; as expected, although groups did not differ regarding gestational age, birth weight Z-score was lower in the "faster-growth" group (0.56 ± 0.72 vs. -1.59 ± 0.96). Liquid chromatography-mass spectrometry lipidomic signatures combined with multivariate analyses made it possible to identify breast-milk lipid species that allowed clear-cut discrimination between groups. Validation of the selected biomarkers was performed using multidimensional statistical, false-discovery-rate and ROC (Receiver Operating Characteristic) tools. Breast-milk associated with faster growth contained more medium-chain saturated fatty acid and sphingomyelin, dihomo-γ-linolenic acid (DGLA)-containing phosphethanolamine, and less oleic acid-containing triglyceride and DGLA-oxylipin. The ability of such biomarkers to predict early-growth was validated in presence of confounding clinical factors but remains to be ascertained in larger cohort studies.

Marine Lipids on Cardiovascular Diseases and Other Chronic Diseases Induced by Diet: An Insight Provided by Proteomics and Lipidomics

Marine lipids, especially ω-3 polyunsaturated fatty acids (PUFAs) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have largely been linked to prevention of diet-induced diseases. The anti-inflammatory and hypolipidemic properties of EPA and DHA supplementation have been well-described. However, there is still a significant lack of information about their particular mechanism of action. Furthermore, repeated meta-analyses have not shown conclusive results in support of their beneficial health effects. Modern "omics" approaches, namely proteomics and lipidomics, have made it possible to identify some of the mechanisms behind the benefits of marine lipids in the metabolic syndrome and related diseases, i.e., cardiovascular diseases and type 2 diabetes. Although until now their use has been scarce, these "omics" have brought new insights in this area of nutrition research. The purpose of the present review is to comprehensively show the research articles currently available in the literature which have specifically applied proteomics, lipidomics or both approaches to investigate the role of marine lipids intake in the prevention or palliation of these chronic pathologies related to diet. The methodology adopted, the class of marine lipids examined, the diet-related disease studied, and the main findings obtained in each investigation will be reviewed.

Changes in liver proteins of rats fed standard and high-fat and sucrose diets induced by fish omega-3 PUFAs and their combination with grape polyphenols according to quantitative proteomics

This study considered the physiological modulation of liver proteins due to the supplementation with fish oils under two dietary backgrounds: standard or high in fat and sucrose (HFHS), and their combination with grape polyphenols. By using a quantitative proteomics approach, we showed that the capacity of the supplements for regulating proteins depended on the diet; namely, 10 different proteins changed into standard diets, while 45 changed into the HFHS diets and only scarcely proteins were found altered in common. However, in both contexts, fish oils were the main regulatory force, although the addition of polyphenols was able to modulate some fish oils' effects. Moreover, we demonstrated the ability of fish oils and their combination with grape polyphenols in improving biochemical parameters and reducing lipogenesis and glycolysis enzymes, enhancing fatty acid beta-oxidation and insulin signaling and ameliorating endoplasmic reticulum stress and protein oxidation when they are included in an unhealthy diet.