Dietary interesterified fat enriched with palmitic acid induces atherosclerosis by impairing macrophage cholesterol efflux and eliciting inflammation

MG-132 activates sodium palmitate-induced autophagy in human vascular smooth muscle cells and inhibits senescence via the PI3K/AKT/mTOR axis

OBJECTIVE

This study aimed to reveal the role and mechanism of MG-132 in delaying hyperlipidemia-induced senescence of vascular smooth muscle cells (VSMCs).

METHODS

Immunohistochemistry and hematoxylin-eosin staining confirmed the therapeutic effect of MG-132 on arterial senescence in vivo and its possible mechanism. Subsequently, VSMCs were treated with sodium palmitate (PA), an activator (Recilisib) or an inhibitor (Pictilisib) to activate or inhibit PI3K, and CCK-8 and EdU staining, wound healing assays, Transwell cell migration assays, autophagy staining assays, reactive oxygen species assays, senescence-associated β-galactosidase staining, and Western blotting were performed to determine the molecular mechanism by which MG-132 inhibits VSMC senescence. Validation of the interaction between MG-132 and PI3K using molecular docking.

RESULTS

Increased expression of p-PI3K, a key protein of the autophagy regulatory system, and decreased expression of the autophagy-associated proteins Beclin 1 and ULK1 were observed in the aortas of C57BL/6J mice fed a high-fat diet (HFD), and autophagy was inhibited in aortic smooth muscle. MG-132 inhibits atherosclerosis by activating autophagy in VSMCs to counteract PA-induced cell proliferation, migration, oxidative stress, and senescence, thereby inhibiting VSMC senescence in the aorta. This process is achieved through the PI3K/AKT/mTOR signaling pathway.

CONCLUSION

MG-132 activates autophagy by inhibiting the PI3K/AKT/mTOR pathway, thereby inhibiting palmitate-induced proliferation, migration, and oxidative stress in vascular smooth muscle cells and suppressing their senescence.

Associations between trans fatty acids and systemic immune-inflammation index: a cross-sectional study

BACKGROUND

Previous studies have demonstrated that trans fatty acids (TFAs) intake was linked to an increased risk of chronic diseases. As a novel systemic inflammatory biomarker, the clinical value and efficacy of the systemic immune-inflammation index (SII) have been widely explored. However, the association between TFAs and SII is still unclear. Therefore, the study aims to investigate the connection between TFAs and SII in US adults.

METHODS

The study retrieved data from the National Health and Nutrition Examination Survey (NHANES) for the years 1999-2000 and 2009-2010. Following the exclusion of ineligible participants, the study encompassed a total of 3047 individuals. The research employed a multivariate linear regression model to investigate the connection between circulating TFAs and SII. Furthermore, the restricted cubic spline (RCS) model was utilized to evaluate the potential nonlinear association. Subgroup analysis was also conducted to investigate the latent interactive factors.

RESULTS

In this investigation, participants exhibited a mean age of 47.40 years, with 53.91% of them being female. Utilizing a multivariate linear regression model, the independent positive associations between the log2-transformed palmitelaidic acid, the log2 transformed-vaccenic acid, the log2-transformed elaidic acid, the log2-transformed linolelaidic acid, and the log2-transformed-total sum of TFAs with the SII (all P < 0.05) were noted. In the RCS analysis, no nonlinear relationship was observed between the log2-transformed palmitelaidic acid, the log2 transformed-vaccenic acid, the log2-transformed elaidic acid, the log2-transformed linolelaidic acid, the log2-transformed-total sum of TFAs and the SII (all P for nonlinear > 0.05). For the stratified analysis, the relationship between the circulating TFAs and the SII differed by the obesity status and the smoking status.

CONCLUSIONS

A positive association was investigated between three types of TFA, the sum of TFAs, and the SII in the US population. Additional rigorously designed studies are needed to verify the results and explore the potential mechanism.

Plant-Based Nutrition: Exploring Health Benefits for Atherosclerosis, Chronic Diseases, and Metabolic Syndrome-A Comprehensive Review

Atherosclerosis, chronic non-communicable diseases, and metabolic syndrome are highly interconnected and collectively contribute to global health concerns that reduce life expectancy and quality of life. These conditions arise from multiple risk factors, including inflammation, insulin resistance, impaired blood lipid profile, endothelial dysfunction, and increased cardiovascular risk. Adopting a plant-based diet has gained popularity as a viable alternative to promote health and mitigate the incidence of, and risk factors associated with, these three health conditions. Understanding the potential benefits of a plant-based diet for human health is crucial, particularly in the face of the rising prevalence of chronic diseases like diabetes, hypertension, dyslipidemia, atherosclerosis, and cancer. Thus, this review focused on the plausible advantages of consuming a type of food pattern for the prevention and/or treatment of chronic diseases, emphasizing the dietary aspects that contribute to these conditions and the evidence supporting the benefits of a plant-based diet for human health. To facilitate a more in-depth analysis, we present separate evidence for each of these three concepts, acknowledging their intrinsic connection while providing a specific focus on each one. This review underscores the potential of a plant-based diet to target the underlying causes of these chronic diseases and enhance health outcomes for individuals and populations.

Dietary Fats and Cognitive Status in Italian Middle-Old Adults

The increase in life expectancy led to a significant rise in the prevalence of age-related neurological diseases, such as cognitive impairment, dementia, and Alzheimer’s disease. Although genetics certainly play a role, nutrition emerged as a key factor in maintaining optimal cognitive function among older adults. Therefore, the study aimed to investigate whether specific categories and subcategories of dietary fats, based on carbon-chain length, are associated with cognitive status in a cohort of 883 Italian participants over the age of 50. Methods: The intake of total, single class of dietary fat, such as saturated fatty acids (SFA), monounsaturated fatty acid (MUFA), and polyunsaturated fatty acid (PUFA), and also single fatty acids grouped according to carbon-chain length, were evaluated by food frequency questionnaires (FFQs). Cognitive health was assessed using the short portable mental status questionnaire (SPMSQ). Results: After adjustment for potential confounding factors subjects with a moderate consumption of both short-chain SFA (for Q2 vs. Q1, OR = 0.23, 95% CI: 0.08, 0.66) and middle-chain SFA specifically lauric acid (C12:0) intake (for Q2 vs. Q1, OR = 0.27, 95% CI: 0.09, 0.77) were less likely to suffer from cognitive impairment. Among single MUFAs, erucic acid (C22:1) intake resulted in an inverse association, in a linear way, with cognitive impairment (for Q4 vs. Q1, OR = 0.04, 95% CI: 0.00, 0.39). Conversely, moderate intake of linoleic acid (C18:2) was associated with cognitive impairment (Q3 vs. Q1, OR = 4.59, 95% CI: 1.51, 13.94). Regarding other PUFAs, individuals consuming moderate intake alpha linolenic acid (C18:3) were less likely to have cognitive impairment (for Q3 vs. Q1, OR = 0.19, 95% CI: 0.06, 0.64). Conclusions: Total SFA intake appeared to be inversely associated with cognitive impairment. Regarding specific subtypes of fatty acids, the results mostly referred to short- and middle-chain SFA. Further studies are needed to validate the results of the present study.

Association between trans fatty acids and COVID-19: A multivariate Mendelian randomization study

Traditional observational studies have suggested a potential association between trans fatty acids (TFAs), which are considered to be health-damaging fatty acids, and coronavirus disease 2019 (COVID-19). However, whether there is a causal relationship between them is currently unclear. We aimed to investigate the causal link between genetically determined TFAs and COVID-19. We performed univariate and multivariate Mendelian randomization (MR) studies using summary statistics from the European Pedigree TFAs (n = 8013), COVID-19 susceptibility (n = 159 840), COVID-19 hospitalization (n = 44 986), and COVID-19 severity (n = 18 152) genome-wide association studies (GWAS). The inverse variance weighted (IVW) method was used as the primary MR analysis, and several other methods were used as supplements. In univariate MR analysis, higher levels of circulating trans, cis-18:2 TFAs were positively associated with a higher COVID-19 hospitalization rate (p < 0.0033; odds ratio [OR] = 1.637; 95% confidence interval [CI]: 1.116-2.401) and COVID-19 severity (p < 0.0033; OR = 2.575; 95% CI: 1.412-4.698). Furthermore, in multivariate MR analysis, trans, cis-18:2 had an independent and significant causal association with a higher COVID-19 hospitalization rate (p = 0.00044; OR = 1.862; 95% CI = 1.316-2.636) and COVID-19 severity (p = 0.0016; OR = 2.268; 95% CI = 1.361-3.779) after the five TFAs were adjusted for each other. Together, our findings provide evidence that trans, cis-18:2 TFAs have an independent and robust causal effect on COVID-19 hospitalization and severity.

Untargeted lipidomics and metagenomics reveal the mechanism of aspirin eugenol ester relieving hyperlipidemia in ApoE-/- mice

Hyperlipidemia is induced by abnormal lipid metabolism, which can cause the occurrence of cardiovascular diseases and lead to grievous injury to health. Studies showed that AEE had a significant therapeutic effect on hyperlipidemia and is likely to be associated with the up-regulation of cholesterol 7-alpha hydroxylase (CYP7A1), the key enzyme for cholesterol conversion to bile acids, but no research confirmed whether the effect of AEE on hyperlipidemia was related to the gut microbiota and liver lipids. At the same time, more and more studies have shown that gut microbiota and lipids are closely related to hyperlipidemia. Hence, in this study, we investigated the effects of AEE on liver lipids through LC-MS-based untargeted lipidomics and the effects of AEE on gut microbiota based on cecal contents metagenomics by Illumina sequencing in HFD-induced hyperlipidemia ApoE-/- mice at the overall level. The results of lipidomics showed that AEE relieved hyperlipidemia by decreasing the concentration of 10 PEs and 12 SMs in the liver and regulating the pathways of glycerophospholipid metabolic pathway, sphingolipid signaling pathway, and NF-kB signaling pathway. The results of metagenomics concluded that AEE treatment changed the composition of gut microbiota and regulated the functions of lipid transport and metabolism, as well as the metabolism of bile acids and secondary bile acids. The results of the joint analysis between lipidomics and metagenomics showed that the abundance of Verrucomicrobia, Verrucomicrobiales, Candidatus_Gastranaerophilales, and Candidatus_Melainabacteria was significantly positively correlated with the concentration of SM (d18:1/18:0) and PE (16:0/18:1) in the process of AEE alleviating hyperlipidemia in mice. In conclusion, these results suggested that the effect of AEE on hyperlipidemia was closely related to the gut microbiota by the change of bile acids and liver lipids.

Effects of commercial non-dairy tea whitener consumption in comparison to milk on lipid profile, histopathology, and liver enzymes in animal model

The pandemic of obesity and other diet-related non-communicable diseases are serious threats to the wellbeing and financial prosperity around the globe. It has been documented that the consumption of processed foods with high levels of refined sugars and fats are the main cause contributing to this phenomenon. The present work was therefore conducted to assess the effects of the consumption of non-dairy tea whiteners (NDTW’s) on lipid profile, histopathology, and liver enzymes of rats for a period of three months. To this end, 30 albino Wister rats (7 weeks old, 130 ± 5 g) was divided into five groups namely control (G1), fed with whole milk (G2), and groups fed with defined dose of commercial NDTW’s (G3, G4, and G5). All rats were provided feed and water ad libitum during the experimental period. At trial completion, the rats were decapitated, and samples (blood, liver) were collected and subjected to blood chemistry (lipid profile) and liver histopathological analyses. Results indicated that as compared to milk, powder NDTW consumption increased the level of cholesterol (69%), triglycerides (98%), and LDL (84%), whereas HDL was non-significantly affected. On the other hand, liquid NDTW consumption led to the increase in triglyceride levels for all NDTW, and yielded 130% increase as compared to milk, which might have been attributed to composition of NDTW. Additionally, liver and renal functional tests yielded non-significant results. The present work concluded that the consumption of NDTW contributed towards derangement and elevation in lipid profile parameters as compared to milk, particularly if consumed for longer period of time.

Nanoformulation of Seaweed Eisenia bicyclis in Albumin Nanoparticles Targeting Cardiovascular Diseases: In Vitro and In Vivo Evaluation

Natural products, especially those derived from seaweeds, are starting to be seen as effective against various diseases, such as cardiovascular diseases (CVDs). This study aimed to design a novel oral formulation of bovine albumin serum nanoparticles (BSA NPs) loaded with an extract of Eisenia bicyclis and to validate its beneficial health effects, particularly targeting hypercholesterolemia and CVD prevention. Small and well-defined BSA NPs loaded with Eisenia bicyclis extract were successfully prepared exhibiting high encapsulation efficiency. Antioxidant activity and cholesterol biosynthesis enzyme 3-hydroxy-3 methylutaryl coenzyme A reductase (HMGR) inhibition, as well as reduction of cholesterol permeation in intestinal lining model cells, were assessed for the extract both in free and nanoformulated forms. The nanoformulation was more efficient than the free extract, particularly in terms of HMGR inhibition and cholesterol permeation reduction. In vitro cytotoxicity and in vivo assays in Wistar rats were performed to evaluate its safety and overall effects on metabolism. The results demonstrated that the Eisenia bicyclis extract and BSA NPs were not cytotoxic against human intestinal Caco-2 and liver HepG2 cells and were also safe after oral administration in the rat model. In addition, an innovative approach was adopted to compare the metabolomic profile of the serum from the animals involved in the in vivo assay, which showed the extract and nanoformulation's impact on CVD-associated key metabolites. Altogether, these preliminary results revealed that the seaweed extract and the nanoformulation may constitute an alternative natural dosage form which is safe and simple to produce, capable of reducing cholesterol levels, and consequently helpful in preventing hypercholesterolemia, the main risk factor of CVDs.

Enhancement of the functionality of women with knee osteoarthritis by a gel formulation with Caryocar coriaceum Wittm ("Pequi") nanoencapsulated pulp fixed oil

Osteoarthritis (OA) is a degenerative joint disease that occurs when there is a change in the mechanical and biological properties of the articular cartilage and the subchondral bone; The condition is more prevalent in women than in men. Pequi oil (PO), which is extracted from the fruits of the pequi tree (Caryocar coriaceum Wittm), is widely used in traditional medicine in the Brazilian northeast for the management of inflammation and joint pain. The aim of this study was to develop a pharmaceutical formulation containing Carbopol® hydrogel nanoencapsulated with pequi pulp fixed oil (PeONC) and evaluate its therapeutic effect on functionality and pain in women with knee osteoarthritis. The study was divided into two stages: Stage 1 - preparation and physico-chemical characterization of the pharmaceutical formulation containing PeONC, cell viability assays and skin irritability testing. Step 2 - A double-blind randomized clinical trial evaluating knee symptoms, quality of life, pressure pain, function, muscle strength and range of motion. The nanoformulation was in a gel form, with a particle size of 209.5 ± 1.06 nm, a pH of 6.23 ± 0.45, a zeta potential of - 23.1 ± 0.4 mV, a polydispersity index of 0.137 ± 0.52, and containing nanocapsules with a spherical shape a polymeric wall and an oily nucleus. The gel showed no cytotoxicity and was not irritating to human skin. The treatment with PeONC increased the strength of the knee flexor and extensor muscles and the total motion range of the knee. In addition, the treatment reduced knee instability, pain, swelling, and locking; There was also an improvement in some items of the SF-36 quality of life questionnaire such as in respect of functional capacity and social aspects. In conclusion, PeONC was found to be a stable, safe formulation with no toxicity in respect of topical use in humans. Additionally, the treatment produced an increase in muscle strength and functionality that was associated with reduced knee symptoms and improved quality of life. Our findings showed that in a group of women treated with PeONC mitigated the symptoms of knee osteoarthritis.

Untargeted and Targeted Metabolomics Reveal the Underlying Mechanism of Aspirin Eugenol Ester Ameliorating Rat Hyperlipidemia via Inhibiting FXR to Induce CYP7A1

Hyperlipidemia is an important lipid disorder and a risk factor for health. Aspirin eugenol ester (AEE) is a novel synthetic compound which is made up of two chemical structural units from aspirin and eugenol. Therapeutic effect of AEE on hyperlipidemia has been confirmed in animal model. But the action mechanism of AEE on hyperlipidemia is still poorly understood. In this study, we investigated the effects of AEE on liver and feces metabolic profile through UPLC-Q-TOF/MS-based untargeted metabolomics in hyperlipidemia hamster induced with high fat diet (HFD), and the effects of AEE on the expression of genes and proteins related to cholesterol and bile acid (BA) in HFD-induced hyperlipidemia SD rat. The concentrations of 26 bile acids (BAs) in the liver from hyperlipidemia SD rat were also quantified with the application of BA targeted metabolomics. The results of untargeted metabolomics showed that the underlying mechanism of AEE on hyperlipidemia was mainly associated with amino acid metabolism, glutathione metabolism, energy metabolism, BA metabolism, and glycerophospholipid metabolism. AEE induced the expression of the BA-synthetic enzymes cholesterol 7α-hydroxylase (CYP7A1) by the inhibition of BA nuclear receptor farnesoid X receptor (FXR) in liver, which resulted in accelerating the conversion of cholesterol into bile acids and excrete in feces. The results of BA targeted metabolomics showed that AEE elevated the glycine-conjugated BA level and decreased the tauro-conjugated BA level. In conclusion, this study found that AEE decreased FXR and increased CYP7A1 in the liver, which might be the possible molecular mechanisms and targets of AEE for anti-hyperlipidemia therapies.

Effects of fatty acids on T cell function: role in atherosclerosis

T cells are among the most common cell types present in atherosclerotic plaques and are increasingly being recognized as a central mediator in atherosclerosis development and progression. At the same time, triglycerides and fatty acids have re-emerged as crucial risk factors for atherosclerosis. Triglycerides and fatty acids are important components of the milieu to which the T cell is exposed from the circulation to the plaque, and increasing evidence shows that fatty acids influence T cell function. In this Review, we discuss the effects of fatty acids on four components of the T cell response - metabolism, activation, proliferation and polarization - and the influence of these changes on the pathogenesis of atherosclerosis. We also discuss how quiescent T cells can undergo a type of metabolic reprogramming induced by exposure to fatty acids in the circulation that influences the subsequent functions of T cells after activation, such as in atherosclerotic plaques.

Elaidic acid induced NLRP3 inflammasome activation via ERS-MAPK signaling pathways in Kupffer cells

Trans fatty acids (TFA) in food can cause liver inflammation. Activation of NOD-like receptor protein-3 (NLRP3) inflammasome is a key factor in the regulation of inflammation. Accumulating evidence suggests that ERS-induced NLRP3 inflammasome activation underlies the pathological basis of various inflammatory diseases, but the precise mechanism has not been fully elucidated. Therefore, this paper focused on TFA, represented by elaidic acid (EA), to investigate the mechanism of liver inflammation. Levels of mRNA and protein were detected by RT-qPCR and Western blotting, the release of proinflammatory cytokines was measured by ELISA, and intracellular Ca²⁺ levels were determined by flow cytometer using Fluo 4-AM fluorescent probes. Our research indicated that EA induced the endoplasmic reticulum stress (ERS) response in Kupffer cells (KCs), accompanied by the activation of the mitogen-activated protein kinase (MAPK) signaling pathway, which resulted in NLRP3 inflammasome formation, and eventually increased the release of inflammatory factors. NLRP3 inflammasome activation was inhibited when KCs were pretreated with ERS inhibitors (4-PBA) and MAPK selective inhibitors. Furthermore, when ERS was blocked, the MAPK pathway was inhibited.

trans-Fatty Acids as an Enhancer of Inflammation and Cell Death: Molecular Basis for Their Pathological Actions

trans-Fatty acids (TFAs) are food-derived fatty acids that possess one or more trans double bonds between carbon atoms. Compelling epidemiological and clinical evidence has demonstrated the association of TFA consumption with various diseases, such as cardiovascular diseases, and neurodegenerative diseases. However, the underlying etiology is poorly understood since the mechanisms of action of TFAs remain to be clarified. Previous studies have shown that single treatment with TFAs induce inflammation and cell death, but to a much lesser extent than saturated fatty acids (SFAs) that are well established as a risk factor for diseases linked with inflammation and cell death, which cannot explain the particularly higher association of TFAs with atherosclerosis than SFAs. In our series of studies, we have established the role of TFAs as an enhancer of inflammation and cell death. We found that pretreatment with TFAs strongly promoted apoptosis induced by either extracellular ATP, one of the damage-associated molecular patterns (DAMPs) leaked from damaged cells, or DNA damaging-agents, including doxorubicin and cisplatin, thorough enhancing activation of the stress-responsive mitogen-activated protein (MAP) kinase p38/c-jun N-terminal kinase (JNK) pathways; pretreatment with SFAs or cis isomers of TFAs had only minor or no effect, suggesting the uniqueness of the pro-apoptotic role of TFAs among fatty acids. Our findings will provide an insight into understanding of the pathogenesis mechanisms, and open up a new avenue for developing prevention strategies and therapies for TFA-related diseases.

Circulating fatty acids and endocannabinoidome-related mediator profiles associated to human longevity

To evaluate whether a peculiar plasma profile of fatty acids and endocannabinoidome (eCBome)-related mediators may be associated to longevity, we assessed them in octogenarians (Old; n=42) living in the east-central mountain area of Sardinia, a High-Longevity Zone (HLZ), compared to sexagenarian (Young; n=21) subjects from the same area, and to Olds (n=22) from the Northern Sardinia indicated as Lower-Longevity Zone (LLZ). We found significant increases in conjugated linoleic acid (CLA) and heptadecanoic acid (17:0) levels in Old-HLZ with respect to younger subjects and Old-LLZ subjects. Young-HLZ subjects exhibited higher circulating levels of pentadecanoic acid (15:0) and retinol. Palmitoleic acid (POA) was elevated in both Young and Old subjects from the HLZ. eCBome profile showed a significantly increased plasma level of the two endocannabinoids, N-arachidonoyl-ethanolamine (AEA) and 2-arachidonoyl-glycerol (2-AG) in Old-HLZ subjects compared to Young-HLZ and Old-LLZ respectively. In addition, we found increased N-oleoyl-ethanolamine (OEA), 2-linoleoyl-glycerol (2-LG) and 2-oleoyl-glycerol (2-OG) levels in Old-HLZ group with respect to Young-HLZ (as for OEA an d 2-LG) and both the Old-LLZ and Young-HLZ for 2-OG. The endogenous metabolite of docosahexaenoic acid (DHA), N-docosahexaenoyl-ethanolamine (DHEA) was significantly increased in Old-HLZ subjects. In conclusion, our results suggest that in the HLZ area, Young and Old subjects exhibited a favourable, albeit distinctive, fatty acids and eCBome profile that may be indicative of a metabolic pattern potentially protective from adverse chronic conditions. These factors could point to a suitable physiological metabolic pattern that may counteract the adverse stimuli leading to age-related disorders such as neurodegenerative and metabolic diseases.

NAFLD and Cardiovascular Diseases: Epidemiological, Mechanistic and Therapeutic Considerations

Overwhelming evidence suggests an association of cardiovascular disease (CVD) with non-alcoholic fatty liver disease (NAFLD); however, the underlying mechanisms remain largely speculative. It is, however, likely that common mechanisms contribute to the development of CVD and NAFLD, with lifestyle factors such as smoking, sedentary lifestyle with poor nutrition habits and physical inactivity being major candidates. These behavioral factors, on a predisposing genetic background, trigger changes in gut microbiota, inflammation, dyslipidemia and oxidative stress, leading to metabolic syndrome, diabetes and obesity as well as atherosclerosis. Treatment options to counteract both the progression and development of CVD and NAFLD include lifestyle interventions, optimal medical therapy of comorbid conditions and, as final possibility, bariatric surgery. As no causal pharmacotherapy of NAFLD is available, further research is urgently needed to address the unmet need of a growing population with NAFLD and CVD.

Interesterified fat consumption since gestation decreases striatal dopaminergic targets levels and gdnf impairing locomotion of adult offspring

Interesterified fat (IF) currently substitutes the hydrogenated vegetable fat (HVF) in processed foods. However, the IF consumption impact on the central nervous system (CNS) has been poorly studied. The current study investigated connections between IF chronic consumption and locomotor impairments in early life period and adulthood of rats and access brain molecular targets related to behavior changes in adulthood offspring. During pregnancy and lactation, female rats received soybean oil (SO) or IF and their male pups received the same maternal supplementation from weaning until adulthood. Pups' motor ability and locomotor activity in adulthood were evaluated. In the adult offspring striatum, dopaminergic targets, glial cell line-derived neurotrophic factor (GDFN) and lipid profile were quantified. Pups from IF supplementation group presented impaired learning concerning complex motor skill and sensorimotor behavior. The same animals showed decreased locomotion in adulthood. Moreover, IF group showed decreased immunoreactivity of all dopaminergic targets evaluated and GDNF, along with important changes in FA composition in striatum. This study shows that the brain modifications induce by IF consumption resulted in impaired motor control in pups and decreased locomotion in adult animals. Other studies about health damages induced by IF consumption may have a contribution from our current outcomes.

Interesterified palm oil impairs glucose homeostasis and induces deleterious effects in liver of Swiss mice

BACKGROUND

Interesterified fats have largely replaced the partially hydrogenated oils which are the main dietary source of trans fat in industrialized food. This process promotes a random rearrangement of the native fatty acids and the results are different triacylglycerol (TAG) molecules without generating trans isomers. The role of interesterified fats in metabolism remains unclear. We evaluated metabolic parameters, glucose homeostasis and inflammatory markers in mice fed with normocaloric and normolipidic diets or hypercaloric and high-fat diet enriched with interesterified palm oil.

METHODS

Male Swiss mice were randomly divided into four experimental groups and submitted to either normolipidic palm oil diet (PO), normolipidic interesterified palm oil diet (IPO), palm oil high-fat diet (POHF) or interesterified palm oil high-fat diet (IPOHF) during an 8 weeks period.

RESULTS

When compared to the PO group, IPO group presented higher body mass, hyperglycemia, impaired glucose tolerance, evidence of insulin resistance and greater production of glucose in basal state during pyruvate in situ assay. We also observed higher protein content of hepatic PEPCK and increased cytokine mRNA expression in the IPO group when compared to PO. Interestingly, IPO group showed similar parameters to POHF and IPOHF groups.

CONCLUSION

The results indicate that substitution of palm oil for interesterified palm oil even on normocaloric and normolipidic diet could negatively modulate metabolic parameters and glucose homeostasis as well as cytokine gene expression in the liver and white adipose tissue. This data support concerns about the effects of interesterified fats on health and could promote further discussions about the safety of the utilization of this unnatural fat by food industry.

Slow-Release H2S Donor Anethole Dithiolethione Protects Liver From Lipotoxicity by Improving Fatty Acid Metabolism

"Lipotoxicity" induced by free fatty acids (FAs) plays a central role in the pathogenesis of many metabolic diseases, with few treatment options available today. Hydrogen sulfide (H₂S), a novel gaseous signaling molecule, has been reported to have a variety of pharmacological properties, but its effect on FAs metabolism remains unclear. The purpose of this study was to investigate the effect and mechanisms of anethole dithiolethione (ADT, a sustained-release H₂S donor) on hepatic FAs metabolism. ADT was administered daily for 4 weeks in male Syrian golden hamsters fed a high fat diet (HFD), and FAs profiles of liver tissues were analyzed using GC-MS. The results showed that in HFD-fed hamsters, ADT treatment significantly reduced the accumulation of toxic saturated and monounsaturated fatty acids (C16:0, C18:0, C16:1, and C18:1n9), while increased the content of n-6 and n-3 series polyunsaturated fatty acids (C20:3n6, C20:4n6, and C22:6n3). Mechanistically, ADT obviously inhibited the overexpression of acetyl-CoA carboxylase1 (ACC1), fatty acid synthase (FAS), and stearoyl-CoA desaturase1 (SCD1), and up-regulated the levels of fatty acid transport proteins (FATPs), liver fatty acid binding protein (L-FABP), carnitine palmitoyltransferase 1α (CPT1α), fatty acid desaturase (FADS)1 and FADS2. Notably, ADT administration significantly promoted Mitofusin1-mediated mitochondrial fusion and fatty acid β-oxidation. These findings suggest that ADT plays a beneficial role by regulating the synthesis, desaturation, β-oxidation, uptake, binding/isolation, and transport of FAs. In conclusion, ADT is effective in improving FAs metabolic disorders and liver injuries caused by HFD, which renders ADT a candidate drug for lipotoxicity-induced diseases.

Mechanisms of Action of trans Fatty Acids

Human studies have established a positive association between the intake of industrial trans fatty acids and the development of cardiovascular diseases, leading several countries to enact laws that restrict the presence of industrial trans fatty acids in food products. However, trans fatty acids cannot be completely eliminated from the human diet since they are also naturally present in meat and dairy products of ruminant animals. Moreover, bans on industrial trans fatty acids have not yet been instituted in all countries. The epidemiological evidence against trans fatty acids by far overshadows mechanistic insights that may explain how trans fatty acids achieve their damaging effects. This review focuses on the mechanisms that underlie the deleterious effects of trans fatty acids by juxtaposing effects of trans fatty acids against those of cis-unsaturated fatty acids and saturated fatty acids (SFAs). This review also carefully explores the argument that ruminant trans fatty acids have differential effects from industrial trans fatty acids. Overall, in vivo and in vitro studies demonstrate that industrial trans fatty acids promote inflammation and endoplasmic reticulum (ER) stress, although to a lesser degree than SFAs, whereas cis-unsaturated fatty acids are protective against ER stress and inflammation. Additionally, industrial trans fatty acids promote fat storage in the liver at the expense of adipose tissue compared with cis-unsaturated fatty acids and SFAs. In cultured hepatocytes and adipocytes, industrial trans fatty acids, but not cis-unsaturated fatty acids or SFAs, stimulate the cholesterol synthesis pathway by activating sterol regulatory element binding protein (SREBP) 2-mediated gene regulation. Interestingly, although industrial and ruminant trans fatty acids show similar effects on human plasma lipoproteins, in preclinical models, only industrial trans fatty acids promote inflammation, ER stress, and cholesterol synthesis. Overall, clearer insight into the molecular mechanisms of action of trans fatty acids may create new therapeutic windows for the treatment of diseases characterized by disrupted lipid metabolism.

Dietary fatty acids and CD36-mediated cholesterol homeostasis: potential mechanisms

Currently, the prevention and treatment of CVD have been a global focus since CVD is the number one cause of mortality and morbidity. In the pathogenesis of CVD, it was generally thought that impaired cholesterol homeostasis might be a risk factor. Cholesterol homeostasis is affected by exogenous factors (i.e. diet) and endogenous factors (i.e. certain receptors, enzymes and transcription factors). In this context, the number of studies investigating the potential mechanisms of dietary fatty acids on cholesterol homeostasis have increased in recent years. As well, the cluster of differentiation 36 (CD36) receptor is a multifunctional membrane receptor involved in fatty acid uptake, lipid metabolism, atherothrombosis and inflammation. CD36 is proposed to be a crucial molecule for cholesterol homeostasis in various mechanisms including absorption/reabsorption, synthesis, and transport of cholesterol and bile acids. Moreover, it has been reported that the amount of fatty acids and fatty acid pattern of the diet influence the CD36 level and CD36-mediated cholesterol metabolism principally in the liver, intestine and macrophages. In these processes, CD36-mediated cholesterol and lipoprotein homeostasis might be impaired by dietary SFA and trans-fatty acids, whereas ameliorated by MUFA in the diet. The effects of PUFA on CD36-mediated cholesterol homeostasis are controversial depending on the amount of n-3 PUFA and n-6 PUFA, and the n-3:n-6 PUFA ratio. Thus, since the CD36 receptor is suggested to be a novel nutrient-sensitive biomarker, the role of CD36 and dietary fatty acids in cholesterol metabolism might be considered in medical nutrition therapy in the near future. Therefore, the novel nutritional target of CD36 and interventions that focus on dietary fatty acids and potential mechanisms underlying cholesterol homeostasis are discussed in this review.

Association of circulating saturated fatty acids with the risk of pregnancy-induced hypertension: a nested case-control study

Circulating saturated fatty acids (SFAs) have been associated with cardiovascular disease. However, little is known about the relationship of SFAs with the risk of pregnancy-induced hypertension (PIH). We conducted a nested case-control study to examine the associations between circulating SFAs and the risk of PIH. A total of 92 PIH cases were matched to 184 controls by age (±2 years) and infant sex from a birth cohort study conducted in Wuhan, China. Levels of circulating fatty acids in plasma were measured using gas chromatography-mass spectrometry. Conditional logistic regressions were conducted to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs). Even-chain SFAs, including myristic acid (14:0) and palmitic acid (16:0), were positively associated with the risk of PIH [ORs (95% CIs): 2.92 (1.27, 6.74) for 14:0 and 2.85 (1.18, 6.89) for 16:0, % by wt]. In contrast, higher levels of very-long-chain SFAs, including arachidic acid (20:0), behenic acid (22:0), and lignoceric acid (24:0), were associated with a lower risk of PIH [ORs (95% CIs): 0.40 (0.17, 0.92) for 20:0, 0.30 (0.12, 0.71) for 22:0 and 0.26 (0.11, 0.64) for 24:0, μg/mL]. For odd-chain SFAs, including pentadecanoic acid (15:0) and heptadecanoic acid (17:0), no significant difference was observed. Our results provided convincing evidence that different subclasses of SFAs showed diverse effects on the risk of PIH. This suggests that dietary very-long-chain SFAs may be a novel means by which to prevent hypertension. Future studies are required to confirm these associations and elucidate the underlying mechanisms.

Sodium Orthovanadate Changes Fatty Acid Composition and Increased Expression of Stearoyl-Coenzyme A Desaturase in THP-1 Macrophages

Vanadium compounds are promising antidiabetic agents. In addition to regulating glucose metabolism, they also alter lipid metabolism. Due to the clear association between diabetes and atherosclerosis, the purpose of the present study was to assess the effect of sodium orthovanadate on the amount of individual fatty acids and the expression of stearoyl-coenzyme A desaturase (SCD or Δ⁹-desaturase), Δ⁵-desaturase, and Δ⁶-desaturase in macrophages. THP-1 macrophages differentiated with phorbol 12-myristate 13-acetate (PMA) were incubated in vitro for 48 h with 1 μM or 10 μM sodium orthovanadate (Na₃VO₄). The estimation of fatty acid composition was performed by gas chromatography. Expressions of the genes SCD, fatty acid desaturase 1 (FADS1), and fatty acid desaturase 2 (FADS2) were tested by qRT-PCR. Sodium orthovanadate in THP-1 macrophages increased the amount of saturated fatty acids (SFA) such as palmitic acid and stearic acid, as well as monounsaturated fatty acids (MUFA)-oleic acid and palmitoleic acid. Sodium orthovanadate caused an upregulation of SCD expression. Sodium orthovanadate at the given concentrations did not affect the amount of polyunsaturated fatty acids (PUFA) such as linoleic acid, arachidonic acid, eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA). In conclusion, sodium orthovanadate changed SFA and MUFA composition in THP-1 macrophages and increased expression of SCD. Sodium orthovanadate did not affect the amount of any PUFA. This was associated with a lack of influence on the expression of FADS1 and FADS2.

The increase of atherogenic index on fatty acids composition as a consequence of trans fat acids reduction in industrialized foods: the Brazilian scenery

Abstract The use of fats with a low melting point is attractive to the food industry, as it contributes to improving the texture, color and stability characteristics of the food. These fats are obtained from vegetable oils through some processes such as hydrogenation or interesterification. However, the partial hydrogenation process leads to the formation of trans fat. In several countries, actions have been taken to eliminate the presence of elaidic acid, a trans fatty acid (C18: 1t) from processed foods. This trans fatty acid and palmitic acid, a common saturated fatty acid (C16: 0) are proven to be atherogenic. The aim of this work was to evaluate the composition of fatty acids of 39 types of commercialized foods in Brazil, including cookies, snacks, wafers, instant noodles, frozen sandwiches and pizzas, mixtures for food preparation, microwave popcorn, margarines, spreadable cheeses and pastry dough. The lipids were extracted and their Fatty Acid Methyl Esters (FAMEs) identified by Gas-Chromatography (GC). The fatty acids found in greater quantity were oleic, linoleic and palmitic acids; whereas the trans fatty acids were detected in 51.3% of the samples. On the other hand, when trans fast were reduced in some foods, it could be observed increases in the palmitic acid (C16:0) content. This high content of palmitic acid is justified by the addition of palm oil and its derivatives, which can be used in interesterified oil mixtures or can be directly used in industrialized food formulations, even without interesterification. Governments and organizations in favor of human health should be aware that the use of dietary fatty acids which compromise the atherogenic index is not a healthy alternative. Consumers should therefore be alerted to the risk of consuming foods containing these fats until the food industry is banned from using them or finds healthier alternatives for making food.

Polarization of Macrophages in Human Adipose Tissue is Related to the Fatty Acid Spectrum in Membrane Phospholipids

Residential macrophages in adipose tissue play a pivotal role in the development of inflammation not only within this tissue, but also affect the proinflammatory status of the whole body. Data on human adipose tissue inflammation and the role of macrophages are rather scarce. We previously documented that the proportion of proinflammatory macrophages in human adipose tissue correlates closely with non-HDL cholesterol concentrations. We hypothesized that this is due to the identical influence of diet on both parameters and decided to analyze the fatty acid spectrum in cell membrane phospholipids of the same individuals as a parameter of the diet consumed. Proinflammatory and anti-inflammatory macrophages were isolated from human adipose tissue (n = 43) and determined by flow cytometry as CD14+CD16+CD36^high and CD14+CD16−CD163+, respectively. The spectrum of fatty acids in phospholipids in the cell membranes of specimens of the same adipose tissue was analyzed, and the proportion of proinflammatory macrophage increased with the proportions of palmitic and palmitoleic acids. Contrariwise, these macrophages decreased with increasing alpha-linolenic acid, total n-3 fatty acids, n-3/n-6 ratio, and eicosatetraenoic acid. A mirror picture was documented for the proportion of anti-inflammatory macrophages. The dietary score, obtained using a food frequency questionnaire, documented a positive relation to proinflammatory macrophages in individuals who consumed predominantly vegetable fat and fish, and individuals who consumed diets based on animal fat without fish and nut consumption. he present data support our hypothesis that macrophage polarization in human visceral adipose tissue is related to fatty acid metabolism, cell membrane composition, and diet consumed. It is suggested that fatty acid metabolism might participate also in inflammation and the risk of developing cardiovascular disease.

Effect of High-Fat Diets on Oxidative Stress, Cellular Inflammatory Response and Cognitive Function

Cognitive dysfunction is linked to chronic low-grade inflammatory stress that contributes to cell-mediated immunity in creating an oxidative environment. Food is a vitally important energy source; it affects brain function and provides direct energy. Several studies have indicated that high-fat consumption causes overproduction of circulating free fatty acids and systemic inflammation. Immune cells, free fatty acids, and circulating cytokines reach the hypothalamus and initiate local inflammation through processes such as microglial proliferation. Therefore, the role of high-fat diet (HFD) in promoting oxidative stress and neurodegeneration is worthy of further discussion. Of particular interest in this article, we highlight the associations and molecular mechanisms of HFD in the modulation of inflammation and cognitive deficits. Taken together, a better understanding of the role of oxidative stress in cognitive impairment following HFD consumption would provide a useful approach for the prevention of cognitive dysfunction.

Interesterified Fats Induce Deleterious Effects on Adipose Tissue and Liver in LDLr-KO Mice

Interesterified fats are being widely used by the food industry in an attempt to replace trans fatty acids. The effect of interesterified fats containing palmitic or stearic acids on lipid metabolism and inflammatory signaling pathways in adipose and hepatic tissues was evaluated. Male LDLr-KO mice were fed a high-fat diet containing polyunsaturated (PUFA), palmitic (PALM), palmitic interesterified (PALM INTER), stearic (STEAR), or stearic interesterified (STEAR INTER) fats for 16 weeks. The expression of genes and protein levels involved in lipid metabolism and inflammatory processes in liver and white adipose tissue was determined by quantitative RT-PCR and by Western blot, respectively. The infiltration of inflammatory cells in hepatic and adipose tissues was determined by eosin and hematoxylin, while liver collagen content was determined by Sirius Red staining. Both interesterified fats increased liver collagen content and JNK phosphorylation. Additionally, the STEAR INTER group developed nonalcoholic steatohepatitis (NASH) associated with higher neutrophil infiltration. PALM INTER induced adipose tissue expansion and enlargement of adipocytes. Furthermore, PALM INTER triggered increased IKK phosphorylation and TNFα protein content, conditions associated with the upstream activation of the NFkB signaling pathway. STEAR INTER induced NASH, while PALM INTER triggered hepatic fibrosis and adipocyte hypertrophy with inflammatory response in LDLr-KO mice.

Bioinformatic and Metabolomic Analysis Reveal Intervention Effects of Chicory in a Quail Model of Hyperuricemia

Background. Hyperuricemia (HUA) is a kind of a metabolic disease that seriously threatens human health worldwide. Chicory, a natural herbal medicine, has an obvious effect of reducing uric acid. The aim of this study is to explore the potential components and pharmacological pathways that may play a role in hypouricemia activity of chicory. Bioinformatics and metabonomics were applied to this research. Firstly, component-target network was used to identify possible components related to the pharmacological properties and their corresponding mechanisms pathway of chicory. Afterwards, animal pharmacodynamic experiments were performed. Blood and stool samples were collected for untargeted metabolomic analysis by dint of UHPLC-Q-TOF/MS methods, and principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were performed for the pattern recognition and characteristic metabolites identification. Significant enriched function pathways were used in bioinformatics suggesting that chicory might have the effect of regulation of lipolysis in adipocytes. PLS-DA analysis was applied to discover differentiating metabolites, and pathway enrichment analysis indicated that chicory had powerful effects of glycosylphosphatidylinositol- (GPI-) anchor biosynthesis, inositol phosphate metabolism, glycerophospholipid metabolism, and steroid hormone biosynthesis. Combining bioinformatics and metabolomics results, we consider that chicory may develop on lowering uric acid by adjusting lipid metabolism. In addition, we chose quail as animal model innovatively and discussed the treatment of hyperuricemia with chicory in multiple methods, which may render reference for the research of HUA.

p53 cooperates with SIRT6 to regulate cardiolipin de novo biosynthesis

The tumor suppressor p53 has critical roles in regulating lipid metabolism, but whether and how p53 regulates cardiolipin (CL) de novo biosynthesis is unknown. Here, we report that p53 physically interacts with histone deacetylase SIRT6 in vitro and in vivo, and this interaction increases following palmitic acid (PA) treatment. In response to PA, p53 and SIRT6 localize to chromatin in a p53-dependent manner. Chromatin p53 and SIRT6 bind the promoters of CDP-diacylglycerol synthase 1 and 2 (CDS1 and CDS2), two enzymes required to catalyze CL de novo biosynthesis. Here, SIRT6 serves as a co-activator of p53 and effectively recruits RNA polymerase II to the CDS1 and CDS2 promoters to enhance CL de novo biosynthesis. Our findings reveal a novel, cooperative model executed by p53 and SIRT6 to maintain lipid homeostasis.

Fructose metabolism, cardiometabolic risk, and the epidemic of coronary artery disease

Despite strong indications that increased consumption of added sugars correlates with greater risks of developing cardiometabolic syndrome (CMS) and cardiovascular disease (CVD), independent of the caloric intake, the worldwide sugar consumption remains high. In considering the negative health impact of overconsumption of dietary sugars, increased attention is recently being given to the role of the fructose component of high-sugar foods in driving CMS. The primary organs capable of metabolizing fructose include liver, small intestine, and kidneys. In these organs, fructose metabolism is initiated by ketohexokinase (KHK) isoform C of the central fructose-metabolizing enzyme KHK. Emerging data suggest that this tissue restriction of fructose metabolism can be rescinded in oxygen-deprived environments. In this review, we highlight recent progress in understanding how fructose metabolism contributes to the development of major systemic pathologies that cooperatively promote CMS and CVD, reference recent insights into microenvironmental control of fructose metabolism under stress conditions and discuss how this understanding is shaping preventive actions and therapeutic approaches.

Micro-environment and intracellular metabolism modulation of adipose tissue macrophage polarization in relation to chronic inflammatory diseases

The accumulation and pro-inflammatory polarization of immune cells, mainly macrophages, in adipose tissue (AT) are considered crucial factors for obesity-induced chronic inflammatory diseases. In this review, we highlighted the role of adipose tissue macrophage (ATM) polarization on AT function in the obese state and the effect of the micro-environment and intracellular metabolism on the dynamic switch of ATMs into their pro-inflammatory or anti-inflammatory phenotypes, which may have distinct influences on obesity-related chronic inflammatory diseases. Obesity-associated metabolic dysfunctions, including those of glucose, fatty acid, cholesterol, and other nutrient substrates such as vitamin D and iron in AT, promote the pro-inflammatory polarization of ATMs and AT inflammation via regulating the interaction between ATMs and adipocytes and intracellular metabolic pathways, including glycolysis, fatty acid oxidation, and reverse cholesterol transportation. Focusing on the regulation of ATM metabolism will provide a novel target for the treatment of obesity-related chronic inflammatory diseases, including insulin resistance, cardiovascular diseases, and cancers.

Interesterified soybean oil promotes weight gain, impaired glucose tolerance and increased liver cellular stress markers

Interesterified fats have largely replaced hydrogenated vegetable fat, which is rich in trans fatty acids, in the food industry as an economically viable alternative, generating interest to study their health effects. The aim of this study was to evaluate the effect that interesterification of oils and fat has on lipid-induced metabolic dysfunction, hepatic inflammation and ER stress. Five week-old male Wistar rats were randomly divided into three experimental groups, submitted to either normocaloric and normolipidic diet containing 10% of lipids from unmodified soybean oil (SO) or from interesterified soybean oil (ISO), and one more group submitted to a high fat diet (HFD) containing 60% of fat from lard as a positive control, for 8 or 16 weeks. Metabolic parameters and hepatic gene expression were evaluated. The HFD consumption led to increased body mass, adiposity and impaired glucose tolerance compared to SO and ISO at both time points of diet. However, the ISO group showed an increased body mass gain, retroperitoneal WAT mass, fasting glucose, and impaired glucose tolerance during ipGTT at 16 weeks compared to SO. Moreover, at 8 weeks, hepatic gene expression of Atf3 and Tnf were increased in the ISO group compared to the SO group. Thus, replacement of natural fat with interesterified fat on a normocaloric and normolipidic diet negatively modulated metabolic parameters and resulted in impaired glucose tolerance in rats.

Perspective: interesterified triglycerides, the recent increase in deaths from heart disease, and elevated blood viscosity

The authors hypothesize that consumption of interesterified fats may be the cause of the continuous increase in cardiovascular deaths in the United States which began in 2011. Interesterification is a method of producing solid fats from vegetable oil and began to supplant partial hydrogenation for this purpose upon recognition of the danger of trans fats to cardiovascular health. Long, straight carbon chains, as are present in saturated and trans fatty acids, decrease the fluidity of the erythrocyte cell membrane, which decreases erythrocyte deformability and increases blood viscosity. This decrease in cell membrane fluidity is caused by increased van der Waals interactions, which also solidify dietary fats. Elevated blood viscosity is favored as the pathogenic mechanism by which trans fats increase cardiovascular mortality because changes in lipoprotein levels do not account for all the mortality attributable to their consumption. The rapid changes in cardiovascular mortality noted with the introduction and withdrawal of trans fats from the food supply are reviewed. The evidence implicating elevated blood viscosity in cardiovascular disease is also reviewed. Data regarding the production and consumption of interesterified fats in the US should be released in order to determine if there is an association with the observed increase in cardiovascular deaths.

Effects of Plant Oil Interesterified Triacylglycerols on Lipemia and Human Health

The position of the fatty acids (sn-1, sn-2 and sn-3) (stereospecific numbering (sn)) in triacylglycerol (TAG) molecules produces a characteristic stereospecificity that defines the physical properties of the fats and influences their absorption, metabolism and uptake into tissues. Fat interesterification is a process that implies a positional distribution of fatty acids (FAs) within the TAG molecules, generating new TAG species, without affecting the FA cis-trans natural balance. The interesterified (IE) fats, frequently used in the food industry comprise fats that are rich in long-chain saturated FAs, such as palmitic acid (16:0) and stearic acid (18:0). Within the interesterified fats, a critical role is played by FA occupying the sn-2 position; in fact, the presence of an unsaturated FA in this specific position influences early metabolic processing and postprandial clearance that in turn could induce atherogenesis and thrombogenesis events. Here, we provide an overview on the role of TAG structures and interesterified palmitic and stearic acid-rich fats on fasting and postprandial lipemia, focusing our attention on their physical properties and their effects on human health.

Palmitate inhibits arthritis by inducing t-bet and gata-3 mRNA degradation in iNKT cells via IRE1α-dependent decay

Long chain fatty acids (LCFAs) exert pro-inflammatory effects in vivo. However, little is known regarding the effect of LCFAs on invariant (i) NKT cell functions. Here, we report an inhibitory effect of saturated LCFAs on transcription factors in iNKT cells. Among the saturated LCFAs, palmitic acid (PA) specifically inhibited IL-4 and IFN-γ production and reduced gata-3 and t-bet transcript levels in iNKT cells during TCR-mediated activation. In iNKT cells, PA was localized and induced dilation in the endoplasmic reticulum and increased the mRNA levels of downstream molecules of IRE1α RNase. Moreover, PA increased the degradation rates of gata-3 and t-bet mRNA, which was restored by IRE1α inhibition or transfection with mutant gata-3 or t-bet, indicating that gata-3 and t-bet are cleaved via regulated IRE1α-dependent decay (RIDD). A PA-rich diet and PA injection suppressed IL-4 and IFN-γ production by iNKT cells in C57BL/6, but not Jα18 knockout mice, which was restored by injection of STF083010, an IRE1α-specific inhibitor. Furthermore, a PA-rich diet and PA injection attenuated arthritis in an iNKT cell-dependent manner. Taken together, our experiments demonstrate that a saturated LCFA induced RIDD-mediated t-bet and gata-3 mRNA degradation in iNKT cells, thereby suppressing arthritis.

Cooperative stimulation of atherogenesis by lipopolysaccharide and palmitic acid-rich high fat diet in low-density lipoprotein receptor-deficient mice

BACKGROUND AND AIMS

Either lipopolysaccharide (LPS) or high-fat diet (HFD) enriched with saturated fatty acid (SFA) promotes atherosclerosis. In this study, we investigated the effect of LPS in combination with SFA-rich HFD on atherosclerosis and how LPS and SFA interact to stimulate inflammatory response in vascular endothelial cells.

METHODS

Low-density lipoprotein receptor-deficient (LDLR^-/-) mice were fed a low-fat diet (LFD), HFD with low palmitic acid (PA) (LP-HFD), or HFD with high PA (HP-HFD) for 20 weeks. During the last 12 weeks, half mice received LPS and half received PBS. After treatment, metabolic parameters and aortic atherosclerosis were analyzed. To understand the underlying mechanisms, human aortic endothelial cells (HAECs) were treated with LPS and/or PA and proinflammatory molecule expression was quantified.

RESULTS

The metabolic study showed that LPS had no significant effect on cholesterol, triglycerides, free fatty acids, but increased insulin and insulin resistance. Both LP-HFD and HP-HFD increased body weight and cholesterol while LP-HFD increased glucose and HP-HFD increased triglycerides, insulin, and insulin resistance. Analysis of aortic atherosclerosis showed that HP-HFD was more effective than LP-HFD in inducing atherosclerosis and LPS in combination with HP-HFD increased atherosclerosis in the thoracic aorta, a less common site for atherosclerosis, as compared with LPS or HP-HFD. To understand the mechanisms, results showed that LPS and PA synergistically upregulated adhesion molecules and proinflammatory cytokines in HAECs.

CONCLUSIONS

LPS and PA-rich HFD cooperatively increased atherogenesis in the thoracic aorta. The synergy between LPS and PA on proinflammatory molecules in HAECs may play an important role in atherogenesis.