Plasma levels of 14:0, 16:0, 16:1n-7, and 20:3n-6 are positively associated, but 18:0 and 18:2n-6 are inversely associated with markers of inflammation in young healthy adults

The same species, different nutrients: Lipidomics analysis of muscle in mud crabs (Scylla paramamosain) fed with lard oil and fish oil

Aiming to assess the effects of lard oil (LO) and fish oil (FO) on the nutritional value of mud crabs (Scylla paramamosain), non-targeted lipidomics analysis was performed on the muscle of crabs after eight weeks of feeding trail. Compared to FO, dietary LO reduced the content of phosphatidylethanolamine (PE) and phosphatidylserine (PS) with 18:0 bound at sn-1/3 site, the content of ether phospholipids containing 20:5n-3 (EPA) and 22:6n-3 (DHA) combined at sn-2 site, and increased the content of ether PE containing 18:0 and 18:1n-9. Furthermore, the deposition of 16:0, 16:1n-7, 18:2n-6, 18:3n-3, 20:4n-6, EPA and DHA at each site of PE, PS, phosphatidylcholine and/or triacylglycerols were reduced by dietary LO, while the DHA content at the sn-2 position of PE was increased. In conclusion, the nutritional value of mud crabs was reduced by dietary LO with the manifestation of variation in FA composition and positional distribution on phospholipids.

PFOS-elicited metabolic perturbation in liver and fatty acid metabolites in testis of adult mice

Introduction

Multiple factors can contribute to sub-fecundity, including genetics, lifestyle, and environmental contaminants. PFASs are characterized as "forever chemicals" due to their ubiquitous contamination and their persistence in the environment, wildlife, and humans. Numerous studies have demonstrated that PFAS exposure adversely affects multiple bodily functions, including liver metabolism and gonadal function. It is unclear, however, how the disruption of hepatic fatty acid metabolism affects testicular function.

Methods

In this study, male mice were administered 0.3 and 3 μg/g body weight of PFOS for 21 days.

Results

Our data showed that PFOS exposure caused hepatic steatosis, as evidenced by significant increases in triglyceride levels, expression of ATP-citrate lyase, and fatty acid synthase, as well as fasting insulin levels. PFOS perturbed the expression levels of hepatokines, of which fibroblast growth factor-21 (Fgf-21), leukocyte cell-derived chemotaxin-2 (Lect-2), and retinol-binding protein-4 (Rbp-4) were significantly reduced, whereas angiopoietin-like 4 (Angptl4) was noticeably increased. While Rbp-4 and Fgf-21 are known to contribute to spermatogenesis and testosterone synthesis. In PFOS-exposed groups, testicular ATP, and testosterone decreased significantly with a significant increase in the expression of peroxisome proliferator-activated receptor-coactivator 1α. Mass spectrophotometry imaging revealed the localization of PFOS in testes, along with significant increases in fatty acid metabolites. These included arachidonic acid, dihomo-α-linolenic acid, dihomo-γ-linolenic acid, oxidized ceramide, diacylglycerol, phosphatidylcholine, and phosphatidylethanolamine, which are associated with inflammation and post-testicular causes of infertility.

Discussion

This study revealed potential links between PFOS-elicited changes in hepatic metabolism and their impacts on testicular biology. This study provides insights into alternative targets elicited by PFOS that can be used to develop diagnostic and therapeutic strategies for improving testicular dysfunction.

Qing-Kai-Ling oral liquid alleviated pneumonia via regulation of intestinal flora and metabolites in rats

Background

Qing-Kai-Ling (QKL) oral liquid, evolving from a classical Chinese formula known as An-Gong-Niu-Huang pills, is a well-established treatment for pneumonia with its mechanism remaining muddled. Studies have shown that the regulation of both intestinal flora and host-microbiota co-metabolism may contribute to preventing and treating pneumonia. The study aimed to investigate the potential mechanism by which QKL alleviates pneumonia from the perspective of 'microbiota-metabolites-host' interaction.

Methods

We evaluated the therapeutic effects of QKL on lipopolysaccharide (LPS)-induced pneumonia rats. To explore the protective mechanism of QKL treatment, a multi-omics analysis that included 16S rDNA sequencing for disclosing the key intestinal flora, the fecal metabolome to discover the differential metabolites, and whole transcriptome sequencing of lung tissue to obtain the differentially expressed genes was carried out. Then, a Spearman correlation was employed to investigate the association between the intestinal flora, the fecal metabolome and inflammation-related indices.

Results

The study demonstrated that pneumonia symptoms were significantly attenuated in QKL-treated rats, including decreased TNF-α, NO levels and increased SOD level. Furthermore, QKL was effective in alleviating pneumonia and provided protection equivalent to that of the positive drug dexamethasone. Compared with the Model group, QKL treatment significantly increased the richness and αlpha diversity of intestinal flora, and restored multiple intestinal genera (e.g., Bifidobacterium, Ruminococcus_torques_group, Dorea, Mucispirillum, and Staphylococcus) that were correlated with inflammation-related indices. Interestingly, the intestinal flora demonstrated a strong correlation with several metabolites impacted by QKL. Furthermore, metabolome and transcriptome analyses showed that enrichment of several host-microbiota co-metabolites [arachidonic acid, 8,11,14-eicosatrienoic acid, LysoPC (20:0/0:0), LysoPA (18:0e/0:0), cholic acid, 7-ketodeoxycholic acid and 12-ketodeoxycholic acid] levels and varying lung gene (Pla2g2a, Pla2g5, Alox12e, Cyp4a8, Ccl19, and Ccl21) expression were observed in the QKL group. Moreover, these metabolites and genes were involved in arachidonic acid metabolism and inflammation-related pathways.

Conclusion

Our findings indicated that QKL could potentially modulate intestinal flora dysbiosis, improve host-microbiota co-metabolism dysregulation and regulate gene expression in the lungs, thereby mitigating LPS-induced pneumonia in rats. The study may provide new ideas for the clinical application and further development of QKL.

Red Blood Cell Membrane Fatty Acid Composition, Dietary Fatty Acid Intake and Diet Quality as Predictors of Inflammation in a Group of Australian Adults

Evidence suggests that diet can play a role in modulating systemic inflammation. This study aims to examine the relationship between fatty acids (FAs) (self-reported dietary intake and red blood cell (RBC) membrane fatty acid concentrations), three diet quality scores, and the plasma concentrations of inflammatory markers (interleukin-6, IL-6; tumour necrosis factor alpha, TNF-α; and C-reactive protein, CRP) in a group of Australian adults (n = 92). Data were collected on their demographic characteristics, health status, supplement intake, dietary intake, RBC-FAs and plasma inflammatory markers over a nine-month period. Mixed-effects models were used to determine the relationship between RBC-FAs, dietary intake of FAs, diet quality scores and inflammatory markers to determine which variable most strongly predicted systemic inflammation. A significant association was identified between dietary saturated fat intake and TNF-α (β = 0.01, p < 0.05). An association was also identified between RBC membrane saturated fatty acids (SFA) and CRP (β = 0.55, p < 0.05). Inverse associations were identified between RBC membrane monounsaturated fatty acids (MUFAs) (β = -0.88, p < 0.01), dietary polyunsaturated fatty acids (PUFAs) (β = -0.21, p < 0.05) and CRP, and the Australian Eating Survey Modified Mediterranean Diet (AES-MED) score and IL-6 (β = -0.21, p < 0.05). In summary, using both objective and subjective measures of fat intake and diet quality, our study has confirmed a positive association between saturated fat and inflammation, while inverse associations were observed between MUFAs, PUFAs, the Mediterranean diet, and inflammation. Our results provide further evidence that manipulating diet quality, in particular fatty acid intake, may be useful for reducing chronic systemic inflammation.

Dihomo-γ-Linolenic Acid (20:3n-6)-Metabolism, Derivatives, and Potential Significance in Chronic Inflammation

Dihomo-γ-linolenic acid (DGLA) has emerged as a significant molecule differentiating healthy and inflamed tissues. Its position at a pivotal point of metabolic pathways leading to anti-inflammatory derivatives or via arachidonic acid (ARA) to pro-inflammatory lipid mediators makes this n-6 polyunsaturated fatty acid (PUFA) an intriguing research subject. The balance of ARA to DGLA is probably a critical factor affecting inflammatory processes in the body. The aim of this narrative review was to examine the potential roles of DGLA and related n-6 PUFAs in inflammatory conditions, such as obesity-associated disorders, rheumatoid arthritis, atopic dermatitis, asthma, cancers, and diseases of the gastrointestinal tract. DGLA can be produced by cultured fungi or be obtained via endogenous conversion from γ-linolenic acid (GLA)-rich vegetable oils. Several disease states are characterized by abnormally low DGLA levels in the body, while others can feature elevated levels. A defect in the activity of ∆6-desaturase and/or ∆5-desaturase may be one factor in the initiation and progression of these conditions. The potential of GLA and DGLA administrations as curative or ameliorating therapies in inflammatory conditions and malignancies appears modest at best. Manipulations with ∆6- and ∆5-desaturase inhibitors or combinations of long-chain PUFA supplements with n-3 PUFAs could provide a way to modify the body's DGLA and ARA production and the concentrations of their pro- and anti-inflammatory mediators. However, clinical data remain scarce and further well-designed studies should be actively promoted.

Roles of Palmitoleic Acid and Its Positional Isomers, Hypogeic and Sapienic Acids, in Inflammation, Metabolic Diseases and Cancer

In the last few years, the monounsaturated hexadecenoic fatty acids are being increasingly considered as biomarkers of health with key functions in physiology and pathophysiology. Palmitoleic acid (16:1n-7) and sapienic acid (16:1n-10) are synthesized from palmitic acid by the action of stearoyl-CoA desaturase-1 and fatty acid desaturase 2, respectively. A third positional isomer, hypogeic acid (16:1n-9) is produced from the partial β-oxidation of oleic acid. In this review, we discuss the current knowledge of the effects of palmitoleic acid and, where available, sapienic acid and hypogeic acid, on metabolic diseases such as diabetes, cardiovascular disease, and nonalcoholic fatty liver disease, and cancer. The results have shown diverse effects among studies in cell lines, animal models and humans. Palmitoleic acid was described as a lipokine able to regulate different metabolic processes such as an increase in insulin sensitivity in muscle, β cell proliferation, prevention of endoplasmic reticulum stress and lipogenic activity in white adipocytes. Numerous beneficial effects have been attributed to palmitoleic acid, both in mouse models and in cell lines. However, its role in humans is not fully understood, and is sometimes controversial. Regarding sapienic acid and hypogeic acid, studies on their biological effects are still scarce, but accumulating evidence suggests that they also play important roles in metabolic regulation. The multiplicity of effects reported for palmitoleic acid and the compartmentalized manner in which they often occur, may suggest the overlapping actions of multiple isomers being present at the same or neighboring locations.

Plasma Fatty Acids Pattern and Dry Eye Disease in the Elderly: The Montrachet Population-Based Study

(1) Background: To investigate the association between plasma fatty acids (FAs) and dry eye disease (DED) in an elderly population; (2) Methods: We conducted a population-based study, the Montrachet study, in individuals older than 75 years. DED was evaluated using the Schirmer I test without anesthesia, tear film breakup time (TFBUT) measurement and fluorescein corneal staining. Plasma FAs were measured in fasting blood using gas chromatography; (3) Results: A total of 740 subjects with a plasma measurement of 25 FAs were included in this study. The mean age was 82.2 ± 3.7 years, and 62.7% were women. DED was present in 35.0% of participants. We identified a plasma FAs pattern positively associated with DED, characterized by low polyunsaturated fatty acids (PUFAs), high monounsaturated fatty acids (MUFAs) and low saturated fatty acids (SFAs) levels. After adjustment for major confounders, individuals in the upper quartile of the FAs pattern scores compared with those in the lower quartile were more likely to present DED (OR 2.46 (95% CI 1.51-4.01), p = 0.001); (4) Conclusion: In this study, we found that a plasma FAs pattern characterized by low PUFAs, high MUFAs and low SFAs was significantly associated with DED in elderly participants.

The assessment of plasma fatty acid profiles in newly diagnosed treatment-naive paediatric Crohn's disease

Fatty acid (FA) profiles as potentially relevant components of Crohn's disease (CD) have been insufficiently analysed. We sought to explore the plasma profiles of n-3 and n-6 polyunsa-turated fatty acids (PUFAs) in newly diagnosed untreated active CD. We included 26 consecutive CD pediatric patients (<19 years) and 14 healthy controls (HCs). Disease characteristics, including inflammatory markers, dietary histories, and the Pediatric Crohn's Disease Activity Index (PCDAI), were obtained. The profiles of plasma FAs in plasma lipid classes were analysed by gas chromatography with FID detection of methyl esters. The erythrocyte sedimentation rate, C-reactive protein level and fecal calprotectin level (all p<0.001) were significantly higher in CD patients than in HCs. Most changes were observed in plasma phospholipids (PLs), such as a higher content of n-3 and changes in n-6 long-chain PUFAs in the CD group. The CD group had a lower ratio of n-6/n-3 PUFAs in PLs (p<0.001) and triacylglycerols (TAGs) (p<0.01). Correlations of the FA content in plasma PLs with disease activity scores of CD were also observed, which were positive for the sum of monounsaturated fatty acids (MUFAs) as well as oleic acid (18:1n-9) (both p<0.05). The metabolism of PUFAs is significantly altered even in treatment-naive newly diagnosed active pediatric CD, and the content of major FAs in PLs correlates with disease activity and inflammatory markers, thus probably contributing to the still unclear early disease pathogenesis.

The Myristic Acid:Docosahexaenoic Acid Ratio Versus the n-6 Polyunsaturated Fatty Acid:n-3 Polyunsaturated Fatty Acid Ratio as Nonalcoholic Fatty Liver Disease Biomarkers

It is well established that diets containing an increased omega-6 polyunsaturated fatty acid (n-6 PUFA) to omega-3 polyunsaturated fatty acid (n-3 PUFA) ratios are linked to inflammation and chronic diseases such as nonalcoholic fatty liver disease (NAFLD). However, the influence of an elevated n-6 PUFA:n-3 PUFA ratio in the tissues requires clarification. Herein, we identified primary experimental and clinical studies where it is possible to compare the performance of the myristic acid (Myr):docosahexaenoic acid (DHA) and n-6 PUFA:n-3 PUFA ratios in the liver and/or serum as potential NAFLD biomarkers. Articles were included if quantitative values of n-6 PUFA, n-3 PUFA, Myr, DHA, and information about liver inflammation or liver disease progression parameters were provided. Overall, most experimental (91.6%) and clinical studies (87.5%) reported higher Myr:DHA ratios associated with inflammation and/or NAFLD progression than the n-6 PUFA:n-3 PUFA ratio. We conclude that the Myr:DHA ratio represents a better biomarker of NAFLD than the n-6 PUFA:n-3 PUFA ratio. Future studies are necessary for verifying this observation.

Omega-7 Mixed Fatty Acid Supplementation Fails to Reduce Serum Inflammatory Biomarkers: A Placebo-Controlled, Double-Blind Randomized Crossover Trial

We report the effects of mixed omega-7 fatty acid supplementation on changes in serum hsCRP, TNFα, and IL-6 levels and self-reported outcomes in people with non-specific chronic musculoskeletal discomfort. Design: A double-blind, placebo-controlled, 1:1 randomized single crossover trial composed of 688 mg/day palmiteolate for the verum and an equivalent amount of medium-chain triglycerides for the placebo. Method: Data were analyzed in two independent groups and as a crossover group. Results: From 211 screened participants in 2017–2019, 56 were randomized. Six participants dropped out and fifty completers contributed to the statistical analyses. At baseline, none of the investigated biomarkers were significantly correlated to subjectively assessed musculoskeletal discomfort levels. For the two-group analysis (n = 26 and n = 24), none of the serum biomarkers reached statistical significance; however, a statistically significant placebo effect was found in the subjective outcomes. Conclusion: For the crossover analysis (n = 50), three weeks of supplementation with n7FA containing 688 mg per day of palmiteolate did not reduce serum inflammatory biomarkers nor did it improve subjectively measured quality of life (QoL) compared to placebo. Future studies should explore appropriate biomarkers, sufficient power, length of dosing, inclusion criteria for volunteers with higher BMI, and the verification of cis-palmiteolate versus trans-palmiteolate.

Distinct Fatty Acid Compositions of HDL Phospholipids Are Characteristic of Metabolic Syndrome and Premature Coronary Heart Disease-Family Study

HDL particles can be structurally modified in atherosclerotic disorders associated with low HDL cholesterol level (HDL-C). We studied whether the lipidome of the main phosphatidylcholine (PC), lysophosphatidylcholine (LPC) and sphingomyelin (SM) species of HDL2 and HDL3 subfractions is associated with premature coronary heart disease (CHD) or metabolic syndrome (MetS) in families where common low HDL-C predisposes to premature CHD. The lipidome was analyzed by LC-MS. Lysophosphatidylcholines were depleted of linoleic acid relative to more saturated and shorter-chained acids containing species in MetS compared with non-affected subjects: the ratio of palmitic to linoleic acid was elevated by more than 30%. A minor PC (16:0/16:1) was elevated (28–40%) in MetS. The contents of oleic acid containing PCs were elevated relative to linoleic acid containing PCs in MetS; the ratio of PC (16:0/18:1) to PC (16:0/18:2) was elevated by 11–16%. Certain PC and SM ratios, e.g., PC (18:0/20:3) to PC (16:0/18:2) and a minor SM 36:2 to an abundant SM 34:1, were higher (11–36%) in MetS and CHD. The fatty acid composition of certain LPCs and PCs displayed a characteristic pattern in MetS, enriched with palmitic, palmitoleic or oleic acids relative to linoleic acid. Certain PC and SM ratios related consistently to CHD and MetS.

Profiling of Serum Oxylipins During the Earliest Stages of Rheumatoid Arthritis

OBJECTIVE

Eicosanoids modulate inflammation via complex networks involving different pathways and downstream mediators, including oxylipins. Although altered eicosanoids are linked to rheumatoid arthritis (RA), suggesting that metabolization is enhanced, the role of oxylipins in disease stratification remains unexplored. This study was undertaken to characterize oxylipin networks during the earliest stages of RA and evaluate their associations with clinical features and treatment outcomes.

METHODS

In total, 60 patients with early RA (according to the American College of Rheumatology/European League Against Rheumatism 2010 criteria), 11 individuals with clinically suspect arthralgia (CSA), and 28 healthy control subjects were recruited. Serum samples were collected at the time of onset. In the early RA group, 50 patients who had not been exposed to disease-modifying antirheumatic drug (DMARD) or glucocorticoid treatment at the time of recruitment were prospectively followed up at 6 and 12 months after having received conventional synthetic DMARDs. A total of 75 oxylipins, mostly derived from arachidonic, eicosapentanoic, and linoleic acids, were identified in the serum by liquid chromatography tandem mass spectrometry.

RESULTS

Univariate analyses demonstrated differences in expression patterns of 14 oxylipins across the RA, CSA, and healthy control groups, with each exhibiting a different trajectory. Network analyses revealed a strong grouping pattern of oxylipins in RA patients, whereas in individuals with CSA, a fuzzy network of oxylipins with higher degree and closeness was found. Partial least-squares discriminant analyses yielded variable important projection scores of >1 for 22 oxylipins, which allowed the identification of 2 clusters. Cluster usage differed among the groups (P = 0.003), and showed associations with disease severity and low rates of remission at 6 and 12 months in RA patients who were initially treatment-naive. Pathway enrichment analyses revealed different precursors and pathways between the groups, highlighting the relevance of the arachidonic acid pathway in individuals with CSA and the lipooxygenase pathway in patients with early RA. In applying distinct oxylipin signatures, subsets of seropositive and seronegative RA could be identified.

CONCLUSION

Oxylipin networks differ across stages during the earliest phases of RA. These distinct oxylipin networks could potentially elucidate pathways with clinical relevance for disease progression, clinical heterogeneity, and treatment response.

Age-related factors that affect B cell responses to vaccination in mice and humans

Aging significantly changes the ability to respond to vaccinations and infections. In this review, we summarize published results on age-related changes in response to infection with the influenza virus and on the factors known to increase influenza risk infection leading to organ failure and death. We also summarize how aging affects the response to the influenza vaccine with a special focus on B cells, which have been shown to be less responsive in the elderly. We show the cellular and molecular mechanisms contributing to the dysfunctional immune response of the elderly to the vaccine against influenza. These include a defective interaction of helper T cells (CD4+) with B cells in germinal centers, changes in the microenvironment, and the generation of immune cells with a senescence-associated phenotype. Finally, we discuss the effects of aging on metabolic pathways and we show how metabolic complications associated with aging lead to immune dysfunction.

Obesity-associated inflammation induces androgenic to estrogenic switch in the prostate gland

BACKGROUND AND OBJECTIVE

Our patient cohort revealed that obesity is strongly associated with steroid-5α reductase type 2 (SRD5A2) promoter methylation and reduced protein expression. The underlying mechanism of prostatic growth in this population is poorly understood. Here we addressed the question of how obesity, inflammation, and steroid hormones affect the development of benign prostatic hyperplasia (BPH).

MATERIAL AND METHODS

We used preadipocytes, macrophages, primary human prostatic stromal cells, prostate tissues from high-fat diet-induced obese mice, and 35 prostate specimens that were collected from patients who underwent transurethral resection of the prostate (TURP). RNA was isolated and quantified with RT-PCR. Genome DNA was extracted and SRD5A2 promoter methylation was determined. Sex hormones were determined by high-performance liquid chromatography-tandem mass spectrometry. Protein was extracted and determined by ELISA test.

RESULTS

In prostatic tissues with obesity, the levels of inflammatory mediators were elevated. SRD5A2 promoter methylation was promoted, but SRD5A2 expression was inhibited. Inflammatory mediators and saturated fatty acid synergistically regulated aromatase activity. Obesity promoted an androgenic to estrogenic switch in the prostate.

CONCLUSIONS

Our findings suggest that obesity-associated inflammation induces androgenic to estrogenic switch in the prostate gland, which may serve as an effective strategy for alternative therapies for management of lower urinary tract symptoms associated with BPH in select individuals.

The Influence of Dietary Fatty Acids on Immune Responses

Diet-derived fatty acids (FAs) are essential sources of energy and fundamental structural components of cells. They also play important roles in the modulation of immune responses in health and disease. Saturated and unsaturated FAs influence the effector and regulatory functions of innate and adaptive immune cells by changing membrane composition and fluidity and by acting through specific receptors. Impaired balance of saturated/unsaturated FAs, as well as n-6/n-3 polyunsaturated FAs has significant consequences on immune system homeostasis, contributing to the development of many allergic, autoimmune, and metabolic diseases. In this paper, we discuss up-to-date knowledge and the clinical relevance of the influence of dietary FAs on the biology, homeostasis, and functions of epithelial cells, macrophages, dendritic cells, neutrophils, innate lymphoid cells, T cells and B cells. Additionally, we review the effects of dietary FAs on the pathogenesis of many diseases, including asthma, allergic rhinitis, food allergy, atopic dermatitis, rheumatoid arthritis, multiple sclerosis as well as type 1 and 2 diabetes.

Effects of the rs3834458 Single Nucleotide Polymorphism in FADS2 on Levels of n-3 Long-chain Polyunsaturated Fatty Acids: A Meta-analysis

OBJECTIVES

Evaluate the effects of the single nucleotide polymorphism (SNP) rs3834458 in the fatty acid desaturase 2 gene (FADS2) on n-3 long-chain polyunsaturated fatty acid (LC-PUFA) levels using statistical meta-analysis.

METHODS

Literatures pertaining to the relationship between the SNP rs3834458 and LC-PUFA were retrieved from three electronic databases. Original information was analyzed using RevMan 5.3, including single statistics, test for heterogeneity, summary statistics and evaluation of publication bias.

RESULTS

In total, five pieces of literature were retrieved and divided into seven trials. We observed that the minor allele (Tdel+deldel) carriers of rs3834458 had higher linolenic acid levels (P < 0.00001) and lower eicosapentaenoic acid (P < 0.00001), docosapentenoic acid (P = 0.005) and docosahexaenoic acid (P < 0.00001) levels compared to those of carrying major allele homozygote (TT).

CONCLUSION

This meta-analysis indicates that minor allele of rs3834458 in FADS2 may result in lower activity of delta-6 desaturase leading to higher ALA and lower EPA, DPA and DHA in blood.

The effect of fatty acids in red blood cell membranes on the dynamics of inflammatory markers following the coronary stent implantation

The effect of 20 fatty acids in erythrocyte cell membranes on the extent of inflammatory response and cell oxidative stress was evaluated using multidimensional statistical data analysis in 54 patients suffering from ischemic heart disease undergoing percutaneous coronary intervention with coronary stent implantation using multidimensional statistical data analysis. A systemic inflammatory response was indicated by an increase of C-reactive protein (CRP), serum amyloid A (SAA) and ceruloplasmin 48 h after stent implantation and by an increase of interleukin-6 (IL-6) 24 h after intervention. The increase of malondialdehyde (MDA) after 48 h was used as a marker of cell damage by oxidative stress. Multiple linear regression revealed statistically significant relationships between concentration of some fatty acids and the magnitude of inflammatory response, or oxidative stress, after stent implantation. The most significant relationship with an increase of plasma CRP was found for myristic acid and, to a lesser extent, for oleic acid. Trans octadecenoic acid, and to a lesser extent palmitooleic and nervonic fatty acids were found in inverse correlation with the CRP increase. The increase of IL-6 showed a statistically significant correlation with myristic acid, to a lesser extent with cis-9-eicosenoic acid and to the least extent with docosahexaenoic acid, inversely with pentadecanoic, γ-linolenic and stearic acids. An increase of oxidative stress (MDA) significantly correlated only with γ-linolenic acid. Other studied markers of inflammatory response to coronary stenting were SAA and ceruloplasmin (Cp). Statistical evaluation revealed that SAA and Cp are not suitable markers for assessment relationships between inflammation and erythrocyte membrane fatty acids.

Application of metabolomics part II: Focus on fatty acids and their metabolites in healthy adults

Fatty acids (FAs) play critical roles in health and disease. The detection of FA imbalances through metabolomics can provide an overview of an individual’s health status, particularly as regards chronic inflammatory disorders. In this study, we aimed to establish sensitive reference value ranges for targeted plasma FAs in a well-defined population of healthy adults. Plasma samples were collected from 159 participants admitted as outpatients. A total of 24 FAs were analyzed using gas chromatography-mass spectrometry, and physiological values and 95% reference intervals were calculated using an approximate method of analysis. The differences among the age groups for the relative levels of stearic acid (P=0.005), the omega-6/omega-3 ratio (P=0.027), the arachidonic acid/eicosapentaenoic acid ratio (P<0.001) and the linoleic acid-produced dihomo-gamma-linolenic acid (P=0.046) were statistically significant. The majority of relative FA levels were higher in males than in females. The levels of myristic acid (P=0.0170) and docosahexaenoic acid (P=0.033) were signifi-cantly different between the sexes. The reference values for the FAs examined in this study represent a baseline for further studies examining the reproducibility of this methodology and sensitivities for nutrient deficiency detection and investigating the biochemical background of pathological conditions. The application of these values to clinical practice will allow for the discrimination between health and disease and contribute to early prevention and treatment.

Resveratrol Modulates Desaturase Expression and Fatty Acid Composition of Cultured Hepatocytes

This study aimed to evaluate whether resveratrol (RSV) and its microbial metabolites dihydro-resveratrol (DHR) and lunularin (LUN) affected fatty acid metabolism and omega-3 polyunsaturated fatty acid (n3-PUFA) synthesis in cultured hepatocytes. To this end, cultured human HepG2 hepatocytes were treated with non-toxic concentrations of these polyphenols (40 μM) and Δ5- and Δ6-desaturase (FADS1 and FADS2, respectively) expression was measured. Resveratrol induced both genes but DHR and LUN showed no effect. Co-incubation of RSV with α-linolenic acid (ALA) also induced FADS1 and FADS2 expression. Moreover, transcription of carnitine palmitoyltransferase 1A and fatty acid synthase expression was increased, indicating induction of β-oxidation and fatty acid synthesis, respectively. Using gas chromatography to measure fatty acid levels, we observed the impact of RSV with and without ALA treatment on fatty acid composition. However, RSV reduced unsaturated while increasing saturated fatty acid levels. We found lower amounts of monounsaturated fatty acids (16:1n-7c, 18:1n-9c, 18:1n7c, and 20:1n-9) and n3-PUFA docosahexaenoic acid whereas unsaturated fatty acid levels, especially of stearic acid, were elevated. Of interest, once we co-incubated the cells with RSV together with bovine serum albumin, we found no differences in gene expression compared to cells without RSV treatment. Although we found no positive effect of RSV on n3-PUFA synthesis, the stilbene could possibly prevent cellular stress by decreasing unsaturated fatty acid levels.

Linoleic acid, glycemic control and Type 2 diabetes

Dietary fat quality, especially the intake of specific types of fatty acids, impacts the risk of many chronic diseases, including cardiovascular diseases, certain cancers and type 2 diabetes (T2DM). A recent pooled analysis involving 20 studies from around the world revealed that higher linoleic acid (18:2n-6 LA) biomarker is associated with dose-dependent decreases in the incidence of T2DM. This latest study corroborates earlier cross-sectional studies and intervention trials showing that biomarkers of LA intake are associated with reduced risk of T2DM and better glycemic control and/or insulin sensitivity. This review highlights key clinical trials that have evaluated the role of LA in glycemia and the related condition, insulin sensitivity.

Dietary linoleic acid intake and blood inflammatory markers: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

The aim of the present study was to investigate the effect of increasing dietary linoleic acid (LA) intake on the blood concentrations of inflammatory markers including cytokines, acute phase reactants and adhesion molecules in adults.

METHODS

We comprehensively searched PubMed, Embase and Cochrane Library for eligible studies. Overall, 30 randomized controlled studies involving 1377 subjects were included for meta-analysis.

RESULTS

No significant effect of higher LA intake was observed for cytokines: tumor necrosis factor (SMD: -0.01; 95% CI: -0.19 to 0.17), interleukin-6 (SMD: 0.11, 95% CI: -0.07 to 0.29), adiponectin (SMD: 0.17, 95% CI: -0.17 to 0.50) and monocyte chemoattractant protein 1 (SMD: 0.14, 95% CI: -0.33 to 0.60). Pooled effect size from 16 studies showed that the C-reactive protein (CRP) concentration was not significantly affected by increasing LA intake (SMD = 0.09, 95% CI: -0.05 to 0.24). However, subgroup and meta-regression analysis suggested that in subjects with a more profound increase of dietary LA intake, LA might increase the blood CRP level. Other acute phase reactants including fibrinogen and plasminogen activator inhibitor-1 and adhesion molecules were not significantly changed when LA was increased in diet. No significant heterogeneity or publication bias was observed, although only a limited number of eligible studies were included for some markers.

CONCLUSION

Our meta-analysis suggested that increasing dietary LA intake does not have a significant effect on the blood concentrations of inflammatory markers. However, the extent of change in dietary LA intake might affect the effect of LA supplementation on CRP.

Occurrence and biological activity of palmitoleic acid isomers in phagocytic cells

Recent studies have highlighted the role of palmitoleic acid [16:1n-7 (cis-9-hexadecenoic acid)] as a lipid hormone that coordinates cross-talk between liver and adipose tissue and exerts anti-inflammatory protective effects on hepatic steatosis and insulin signaling in murine models of metabolic disease. More recently, a 16:1n-7 isomer, cis-7-hexadecenoic acid (16:1n-9), that also possesses marked anti-inflammatory effects, has been described in human circulating monocytes and monocyte-derived macrophages. By using gas chromatographic/mass spectrometric analyses of dimethyl disulfide derivatives of fatty acyl methyl esters, we describe in this study the presence of a third 16:1 isomer, sapienic acid [16:1n-10 (6-cis-hexadecenoic acid)], in phagocytic cells. Cellular levels of 16:1n-10 appear to depend not only on the cellular content of linoleic acid, but also on the expression level of fatty acid desaturase 2, thus revealing a complex regulation both at the enzyme level, via fatty acid substrate competition, and directly at the gene level. However, unlike 16:1n-7 and 16:1n-9, 16:1n-10 levels are not regulated by the activation state of the cell. Moreover, while 16:1n-7 and 16:1n-9 manifest strong anti-inflammatory activity when added to the cells at low concentrations (10 μM), notably higher concentrations of 16:1n-10 are required to observe a comparable effect. Collectively, these results suggest the presence in phagocytic cells of an unexpected variety of 16:1 isomers, which can be distinguished on the basis of their biological activity and cellular regulation.

Fatty Acids in Nephrotic Syndrome and Chronic Kidney Disease

The role of fatty acids (FAs) in inflammation and in the related chronic diseases has been demonstrated. However, there is a lack of consistent and agreed knowledge about the role of FA profile and renal physiology and pathology, most articles focusing on the effect of polyunsaturated FAs supplementation, without considering the impact of basal FA metabolism on the efficacy of the supplementation. Here, we have summarized the specific literature concerning the assessment of circulating FA in 2 renal diseases, namely nephrotic syndrome and chronic kidney disease, also under hemodialytic treatment, and have received the most significant contributions in the last years. The effects of changes of FA profile and metabolism and the possible involvement of polyunsaturated FA metabolites in raising and modulating inflammation are discussed.

Vitamin D prenatal programming of childhood metabolomics profiles at age 3 y

Background: Vitamin D deficiency is implicated in a range of common complex diseases that may be prevented by gestational vitamin D repletion. Understanding the metabolic mechanisms related to in utero vitamin D exposure may therefore shed light on complex disease susceptibility.Objective: The goal was to analyze the programming role of in utero vitamin D exposure on children's metabolomics profiles.Design: First, unsupervised clustering was done with plasma metabolomics profiles from a case-control subset of 245 children aged 3 y with and without asthma from the Vitamin D Antenatal Asthma Reduction Trial (VDAART), in which pregnant women were randomly assigned to vitamin D supplementation or placebo. Thereafter, we analyzed the influence of maternal pre- and postsupplement vitamin D concentrations on cluster membership. Finally, we used the metabolites driving the clustering of children to identify the dominant metabolic pathways that were influential in each cluster.Results: We identified 3 clusters of children characterized by 1) high concentrations of fatty acids and amines and low maternal postsupplement vitamin D (mean ± SD; 27.5 ± 11.0 ng/mL), 2) high concentrations of amines, moderate concentrations of fatty acids, and normal maternal postsupplement vitamin D (34.0 ± 14.1 ng/mL), and 3) low concentrations of fatty acids, amines, and normal maternal postsupplement vitamin D (35.2 ± 15.9 ng/mL). Adjusting for sample storage time, maternal age and education, and both child asthma and vitamin D concentration at age 3 y did not modify the association between maternal postsupplement vitamin D and cluster membership (P = 0.0014). Maternal presupplement vitamin D did not influence cluster membership, whereas the combination of pre- and postsupplement concentrations did (P = 0.03).Conclusions: Young children can be clustered into distinct biologically meaningful groups by their metabolomics profiles. The clusters differed in concentrations of inflammatory mediators, and cluster membership was influenced by in utero vitamin D exposure, suggesting a prenatal programming role of vitamin D on the child's metabolome. This trial was registered at clinicaltrials.gov as NCT00920621.

Plasma metabolite abundances are associated with urinary enterolactone excretion in healthy participants on controlled diets

Enterolignans, products of gut bacterial metabolism of plant lignans, have been associated with reduced risk of chronic diseases, but their association with other plasma metabolites is unknown. We examined plasma metabolite profiles according to urinary enterolignan excretion in a cross-sectional analysis using data from a randomized crossover, controlled feeding study. Eighty healthy adult males and females completed two 28-day feeding periods differing by glycemic load, refined carbohydrate, and fiber content. Lignan intake was calculated from food records using a polyphenol database. Targeted metabolomics was performed by LC-MS on plasma from fasting blood samples collected at the end of each feeding period. Enterolactone (ENL) and enterodiol, were measured in 24 h urine samples collected on the penultimate day of each study period using GC-MS. Linear mixed models were used to test the association between enterolignan excretion and metabolite abundances. Pathway analyses were conducted using the Global Test. Benjamini-Hochberg false discovery rate (FDR) was used to control for multiple testing. Of the metabolites assayed, 121 were detected in all samples. ENL excretion was associated positively with plasma hippuric acid and melatonin, and inversely with epinephrine, creatine, glycochenodeoxycholate, and glyceraldehyde (P < 0.05). Hippuric acid only satisfied the FDR of q < 0.1. END excretion was associated with myristic acid and glycine (q < 0.5). Two of 57 pathways tested were associated significantly with ENL, ubiquinone and terpenoid-quinone biosynthesis, and inositol phosphate metabolism. These results suggest a potential role for ENL or ENL-metabolizing gut bacteria in regulating plasma metabolites.

Fatty Acids and NLRP3 Inflammasome-Mediated Inflammation in Metabolic Tissues

Worldwide obesity rates have reached epidemic proportions and significantly contribute to the growing prevalence of metabolic diseases. Chronic low-grade inflammation, a hallmark of obesity, involves immune cell infiltration into expanding adipose tissue. In turn, obesity-associated inflammation can lead to complications in other metabolic tissues (e.g., liver, skeletal muscle, pancreas) through lipotoxicity and inflammatory signaling networks. Importantly, although numerous signaling pathways are known to integrate metabolic and inflammatory processes, the nucleotide-binding and oligomerization domain-like receptor, leucine-rich repeat and pyrin domain-containing 3 (NLRP3) inflammasome is now noted to be a key regulator of metabolic inflammation. The NLRP3 inflammasome can be influenced by various metabolites, including fatty acids. Specifically, although saturated fatty acids may promote NLRP3 inflammasome activation, monounsaturated fatty acids and polyunsaturated fatty acids have recently been shown to impede NLRP3 activity. Therefore, the NLRP3 inflammasome and associated metabolic inflammation have key roles in the relationships among fatty acids, metabolites, and metabolic disease. This review focuses on the ability of fatty acids to influence inflammation and the NLRP3 inflammasome across numerous metabolic tissues in the body. In addition, we explore some perspectives for the future, wherein recent work in the immunology field clearly demonstrates that metabolic reprogramming defines immune cell functionality. Although there is a paucity of information about how diet and fatty acids modulate this process, it is possible that this will open up a new avenue of research relating to nutrient-sensitive metabolic inflammation.

Free Fatty Acids Profiles Are Related to Gut Microbiota Signatures and Short-Chain Fatty Acids

A growing body of evidence highlights the relevance of free fatty acids (FFA) for human health, and their role in the cross talk between the metabolic status and immune system. Altered serum FFA profiles are related to several metabolic conditions, although the underlying mechanisms remain unclear. Recent studies have highlighted the link between gut microbiota and host metabolism. However, although most of the studies have focused on different clinical conditions, evidence on the role of these mediators in healthy populations is lacking. Therefore, we have addressed the analysis of the relationship among gut microbial populations, short-chain fatty acid (SCFA) production, FFA levels, and immune mediators (IFNγ, IL-6, and MCP-1) in 101 human adults from the general Spanish population. Levels of selected microbial groups, representing the major phylogenetic types present in the human intestinal microbiota, were determined by quantitative PCR. Our results showed that the intestinal abundance of Akkermansia was the main predictor of total FFA serum levels, displaying a negative association with total FFA and the pro-inflammatory cytokine IL-6. Similarly, an altered FFA profile, identified by cluster analysis, was related to imbalanced levels of Akkermansia and Lactobacillus as well as increased fecal SCFA, enhanced IL-6 serum levels, and higher prevalence of subclinical metabolic alterations. Although no differences in nutritional intakes were observed, divergent patterns in the associations between nutrient intakes with intestinal microbial populations and SCFA were denoted. Overall, these findings provide new insights on the gut microbiota–host lipid metabolism axis and its potential relevance for human health, where FFA and SCFA seem to play an important role.

Breaking Up Prolonged Sitting Alters the Postprandial Plasma Lipidomic Profile of Adults With Type 2 Diabetes

Context

Postprandial dysmetabolism in type 2 diabetes (T2D) is exacerbated by prolonged sitting and may trigger inflammation and oxidative stress. It is unknown what impact countermeasures to prolonged sitting have on the postprandial lipidome.

Objective

In this study, we investigated the effects of regular interruptions to sitting, compared with prolonged sitting, on the postprandial plasma lipidome.

Design

Randomized crossover experimental trial.

Setting

Participants underwent three 7-hour conditions: uninterrupted sitting (SIT); light-intensity walking interruptions (LW); and simple resistance activity interruptions (SRA).

Participants and Samples

Baseline (fasting) and 7-hour (postprandial) plasma samples from 21 inactive overweight/obese adults with T2D were analyzed for 338 lipid species using mass spectrometry.

Main Outcome Measures

Using mixed model analysis (controlling for baseline outcome variable, gender, body mass index, and condition order), the percentage change in lipid species (baseline to 7 hours) was compared between conditions with Benjamini-Hochberg correction.

Results

Thirty-seven lipids were different between conditions (P < 0.05). Compared with SIT, postprandial elevations in diacylglycerols, triacylglycerols, and phosphatidylethanolamines were attenuated in LW and SRA. Plasmalogens and lysoalkylphosphatidylcholines were reduced in SIT, compared with attenuated reductions or elevations in LW and SRA. Phosphatidylserines were elevated with LW, compared with reductions in SIT and SRA.

Conclusion

Compared with SIT, LW and SRA were associated with reductions in lipids associated with inflammation; increased concentrations of lipids associated with antioxidant capacity; and differential changes in species associated with platelet activation. Acutely interrupting prolonged sitting time may impart beneficial effects on the postprandial plasma lipidome of adults with T2D. Evidence on longer-term intervention is needed.

Influence of toll-like receptor 4 gene variants and plasma fatty acid profile on systemic inflammation: A population-based cross-sectional study

OBJECTIVE

The aim of this study was to investigate the interaction of toll-like receptor 4 (TLR4) gene single nucleotide polymorphism (SNP) and plasma fatty acid (FA) profile in modulating risk for systemic inflammation.

METHODS

In all, 262 adult (19-59 y) participants of the Health Survey of São Paulo met the inclusion criteria. Anthropometric parameters, blood pressure, plasma inflammatory biomarker concentration, and fatty acid profile were measured and four SNPs of the TLR4 gene (rs4986790, rs4986791, rs11536889, and rs5030728) were genotyped. Multivariate cluster analysis was performed to stratify individuals based on levels of 11 plasma inflammatory biomarkers into two groups: inflammatory (INF) and noninflammatory (NINF).

RESULTS

No association was found between any of the SNPs studied and systemic inflammation. The INF cluster had higher palmitic acid levels (P = 0.039) and estimated stearoyl coenzyme A desaturase activity (P = 0.045) and lower polyunsaturated fatty acid (P = 0.011), ω-6 fatty acid (P = 0.018), arachidonic acid (P = 0.002) levels, and estimated δ-5 desaturase activity (P = 0.025) compared with the NINF cluster. Statistically significant interaction between rs11536889 and arachidonic acid/eicosapentaenoic acid (AA/EPA) ratio (P = 0.034) was found to increase the odds of belonging to the INF cluster when individuals had the variant allele C and were at the higher percentile of AA/EPA plasma ratio.

CONCLUSION

Plasma fatty acid profile modulated the odds of belonging to the INF cluster depending on genotypes of TRL4 gene polymorphisms.

Intestinal Dysbiosis Is Associated with Altered Short-Chain Fatty Acids and Serum-Free Fatty Acids in Systemic Lupus Erythematosus

Metabolic impairments are a frequent hallmark of systemic lupus erythematosus (SLE). Increased serum levels of free fatty acids (FFA) are commonly found in these patients, although the underlying causes remain elusive. Recently, it has been suggested that factors other than inflammation or clinical features may be involved. The gut microbiota is known to influence the host metabolism, the production of short-chain fatty acids (SCFA) playing a potential role. Taking into account that lupus patients exhibit an intestinal dysbiosis, we wondered whether altered FFA levels may be associated with the intestinal microbial composition in lupus patients. To this aim, total and specific serum FFA levels, fecal SCFA levels, and gut microbiota composition were determined in 21 SLE patients and 25 healthy individuals. The Firmicutes to Bacteroidetes (F/B) ratio was strongly associated with serum FFA levels in healthy controls (HC), even after controlling for confounders. However, this association was not found in lupus patients, where a decreased F/B ratio and increased FFA serum levels were noted. An altered production of SCFA was related to the intestinal dysbiosis in lupus, while SCFA levels paralleled those of serum FFA in HC. Although a different serum FFA profile was not found in SLE, specific FFA showed distinct patterns on a principal component analysis. Immunomodulatory omega-3 FFA were positively correlated to the F/B ratio in HC, but not in SLE. Furthermore, divergent associations were observed for pro- and anti-inflammatory FFA with endothelial activation biomarkers in lupus patients. Overall, these findings support a link between the gut microbial ecology and the host metabolism in the pathological framework of SLE. A potential link between intestinal dysbiosis and surrogate markers of endothelial activation in lupus patients is supported, FFA species having a pivotal role.

Dietary polyunsaturated fatty acids and incidence of end-stage renal disease in the Southern Community Cohort Study

BACKGROUND

Whether polyunsaturated fatty acids (PUFA) are associated with end-stage renal disease (ESRD) in populations with a high burden of risk factors for kidney disease is unknown. We sought to determine whether PUFA intake is associated with ESRD.

METHODS

We conducted a nested case-control study of ESRD within the Southern Community Cohort Study (SCCS), a prospective cohort of low-income blacks and whites in the southeastern US (2002-2009). Through 2012, 1,074 incident ESRD cases were identified by linkage with the United States Renal Data System and matched to 3,230 controls by age, sex and race. Dietary intake of total, n-3 or n-6 PUFA was assessed from a validated food frequency questionnaire administered at baseline. Odds ratios (ORs) and 95 % confidence intervals (CIs) were computed from logistic regression models that included matching variables, body mass index, smoking, diabetes, hypertension, education, income, total energy intake and percent energy from protein and saturated fat.

RESULTS

The mean (SD) age of participants was 55 (9) years. Most participants were women (55 %), black (87 %), with hypertension (67 %) and on average obtained 8 % of their energy from PUFA. Higher PUFA intake was marginally associated with a lower risk of ESRD in adjusted analyses. The adjusted odds ratios (95 % confidence intervals) for ESRD for the 5th vs. 1st quintile of PUFA were 0.79 (0.60-1.05; P trend = 0.06) for total PUFA, 0.81 (0.61-1.06; P trend = 0.04) for n-6 PUFA and 0.93 (0.71-1.21; P trend = 0.45) for n-3 PUFA.

CONCLUSIONS

We observed a marginally significant inverse trend between dietary PUFA intake and ESRD incidence, mainly driven by n-6 fatty acid intake. Our findings require replication but suggest that a diet rich in n-6 PUFA may prevent ESRD development in a population with a high burden of kidney disease risk factors.

Fatty acid profile in erythrocyte membranes and plasma phospholipids affects significantly the extent of inflammatory response to coronary stent implantation

In coronary heart disease, the treatment of significant stenosis by percutaneous coronary intervention (PCI) with stent implantation elicits local and systemic inflammatory responses. This study was aimed at evaluation of the dynamics of inflammatory response and elucidation of the relationship between the fatty acid profile of red blood cell (RBC) membranes or plasma phospholipids and inflammation after PCI. High-sensitivity C-reactive protein (hsCRP), interleukin-6 (IL-6), serum amyloid A (SAA), malondialdehyde (MDA) and the fatty acid profiles were determined in patients with advanced coronary artery disease undergoing PCI before, 24 h and 48 h after drug-eluting stent implantation (n=36). Patients after PCI exhibited a significant increase in studied markers (hsCRP, IL-6, SAA, MDA). Many significant associations were found between the increase of IL-6, resp. SAA and the amounts of n-6 polyunsaturated fatty acids (namely linoleic, dihomo-gamma-linolenic, docosatetraenoic and docosapentaenoic acid), resp. saturated fatty acids (pentadecanoic, stearic, nonadecanoic) in erythrocyte membranes. The magnitude of the inflammatory response to PCI is related to erythrocyte membrane fatty acid profile, which seems to be a better potential predictor of elevation of inflammatory markers after PCI than plasma phospholipids.

Non-Esterified Fatty Acids Profiling in Rheumatoid Arthritis: Associations with Clinical Features and Th1 Response

Objectives

Since lipid compounds are known to modulate the function of CD4⁺ T-cells and macrophages, we hypothesize that altered levels of serum non-esterified fatty acids (NEFA) may underlie rheumatoid arthritis (RA) pathogenesis.

Methods

Serum levels of NEFA (palmitic, stearic, palmitoleic, oleic, linoleic, γ-linoleic, arachidonic –AA–, linolenic, eicosapentaenoic –EPA– and docosahexaenoic –DHA–) were quantified by LC-MS/MS after methyl-tert-butylether (MTBE)-extraction in 124 RA patients and 56 healthy controls (HC). CD4⁺ phenotype was studied by flow cytometry. TNFα, IL-8, VEGF, GM-CSF, IFNγ, IL-17, CCL2, CXCL10, leptin and resistin serum levels were quantified by immunoassays. The effect of FA on IFNγ production by PBMC was evaluated in vitro.

Results

Lower levels of palmitic (p<0.0001), palmitoleic (p = 0.002), oleic (p = 0.010), arachidonic (p = 0.027), EPA (p<0.0001) and DHA (p<0.0001) were found in RA patients, some NEFA being altered at onset. Cluster analysis identified a NEFA profile (hallmarked by increased stearic and decreased EPA and DHA) overrepresented in RA patients compared to HC (p = 0.002), being associated with clinical features (RF, shared epitope and erosions), increased IFNγ expression in CD4⁺ T-cells (p = 0.002) and a Th1-enriched serum milieu (IFNγ, CCL2 and CXCL10, all p<0.005). In vitro assays demonstrated that imbalanced FA could underlie IFNγ production by CD4⁺ T-cells. Finally, changes on NEFA levels were associated with clinical response upon TNFα-blockade.

Conclusion

An altered NEFA profile can be found in RA patients associated with clinical characteristics of aggressive disease and enhanced Th1 response. These results support the relevance of lipidomic studies in RA and provide a rationale for new therapeutic targets.

Foamy Monocytes Are Enriched in cis-7-Hexadecenoic Fatty Acid (16:1n-9), a Possible Biomarker for Early Detection of Cardiovascular Disease

Human monocytes respond to arachidonic acid, a secretory product of endothelial cells, by activating the de novo pathway of fatty acid biosynthesis, resulting in the acquisition of a foamy phenotype due to accumulation of cytoplasmic lipid droplets. Recruitment of foamy monocytes to endothelium is a key step in the formation of atherosclerotic plaques. Here we describe that lipid droplets of foamy monocytes are enriched in a rather uncommon fatty acid, cis-7-hexadecenoic acid (16:1n-9), a positional isomer of palmitoleic acid. 16:1n-9 was found to possess an anti-inflammatory activity both in vitro and in vivo that is comparable with that of omega-3 fatty acids and clearly distinguishable from the effects of palmitoleic acid. Selective accumulation in neutral lipids of phagocytic cells of an uncommon fatty acid reveals an early phenotypic change that may provide a biomarker of proatherogenicity, and a potential target for intervention in the early stages of cardiovascular disease.

Serum n-6 polyunsaturated fatty acids, Δ5- and Δ6-desaturase activities, and risk of incident type 2 diabetes in men: the Kuopio Ischaemic Heart Disease Risk Factor Study

BACKGROUND

The role of n-6 (ω-6) polyunsaturated fatty acids (PUFAs) in type 2 diabetes (T2D) is inconclusive. In addition, little is known about how factors involved in PUFA metabolism, such as zinc, may affect the associations.

OBJECTIVES

We investigated the associations of serum n-6 PUFAs and activities of enzymes involved in PUFA metabolism, Δ5 desaturase (D5D) and Δ6 desaturase (D6D), with T2D risk to determine whether serum zinc concentrations could modify these associations.

DESIGN

The study included 2189 men from the prospective Kuopio Ischaemic Heart Disease Risk Factor Study, aged 42-60 y and free of T2D at baseline in 1984-1989. T2D was assessed by self-administered questionnaires, by fasting and 2-h oral-glucose-tolerance test blood glucose measurement at re-examination rounds 4, 11, and 20 y after baseline, and by record linkage to the hospital discharge registry and the reimbursement register on diabetes medication expenses. Multivariate-adjusted Cox proportional hazards regression models were used to analyze associations.

RESULTS

During the average follow-up of 19.3 y, 417 men developed T2D. Those with higher estimated D5D activity (extreme-quartile HR: 0.55; 95% CI: 0.41, 0.74; P-trend < 0.001) and higher concentrations of total n-6 PUFAs (HR: 0.54; 95% CI: 0.41, 0.73; P-trend < 0.001), linoleic acid (LA; HR: 0.52; 95% CI: 0.39, 0.70; P-trend < 0.001), and arachidonic acid (AA; HR: 0.62; 95% CI: 0.46, 0.85; P-trend = 0.007) had a lower risk and those with higher concentrations of γ-linolenic acid (GLA; HR: 1.28; 95% CI: 0.98, 1.68; P = 0.021) and dihomo-γ-linolenic acid (DGLA; HR: 1.38; 95% CI: 1.04, 1.84; P-trend = 0.005) and higher D6D activity had a higher (HR: 1.50; 95% CI: 1.14, 1.97; P-trend < 0.001) multivariate-adjusted risk of T2D. Zinc mainly modified the association with GLA on T2D risk, with a higher risk observed among those with serum zinc concentrations above the median (P-interaction = 0.04).

CONCLUSIONS

Higher serum total n-6 PUFA, LA, and AA concentrations and estimated D5D activity were associated with a lower risk of incident T2D, and higher GLA and DGLA concentrations and estimated D6D activity were associated with a higher risk. In addition, a higher serum zinc concentration modified the association of GLA on the risk of T2D.

Association between serum fatty acid composition and innate immune markers in healthy adults

BACKGROUND/OBJECTIVES

Supplementation with n-3 polyunsaturated fatty acids (PUFAs) has been shown to generally decrease levels of innate immune markers and inflammatory cytokines, but the specific associations between blood levels of PUFAs and those of innate immune markers have not been investigated. Thus, the present study was conducted to test the hypothesis that innate immune markers as well as cytokines are negatively associated with n-3 PUFAs but positively associated with n-6 PUFAs in healthy adults.

MATERIALS/METHODS

One hundred sixty-five healthy Korean adults aged 25-70 years old were included in this cross-sectional study.

RESULTS

Serum levels of n-3 PUFAs, such as 18:3n3, 20:5n3, 22:5n3, and 22:6n3 were negatively correlated with eosinophil and basophil counts and TNF-α, IFN-γ, IL-4, and IL-10 levels. Multivariate analysis also showed that serum levels of n-3 PUFAs were negatively associated with monocyte, eosinophil, and basophil counts and TNF-α, IFN-γ, IL-4, and IL-12 levels. Additionally, the ratio of 20:4n6 to 20:5n3 was positively correlated with eosinophil counts and associated with TNF-α, IFN-γ, and IL-4 levels. However, NK cell activity was not associated with serum fatty acid composition.

CONCLUSIONS

Innate immune markers such as eosinophil, monocyte, and basophil counts were inversely associated with serum levels of n-3 PUFAs, but were positively associated with the 20:4n6/20:5n3 ratio in this population.

New obesity classification criteria as a tool for bariatric surgery indication

Obesity plays relevant pathophysiological role in the development of health problems, arising as result of complex interaction of genetic, nutritional, and metabolic factors. Due to the role of adipose tissue in lipid and glucose metabolism, and low grade inflammation, it is necessary to classify obesity on the basis of body fat composition and distribution, rather than the simply increase of body weight, and the Body Mass Index. The new term of adiposopathy (‘‘sick fat’’) clearly defines the pathogenic role of adipose tissue. Four phenotypes of obese individuals have been described: (1) normal weight obese (NWO); (2) metabolically obese normal weight; (3) metabolically healthy obese; and (4) metabolically unhealthy obese or “at risk” obese. Moreover, sarcopenic obesity has been related to all the phenotypes. The category of normal weight lean, represented by metabolically healthy normal weight has been classified to distinguish from NWO. It is crucial to recommend a bariatric surgery taking into account adiposopathy and sick fat that occurs with the expansion of fat mass, changing the inflammatory and metabolic profile of the patient. Body fat percentage and genetic polymorphism have to be evaluated to personalize the best bariatric surgery intervention.

Modulation of C-reactive protein and plasma omega-6 fatty acid levels by phospholipase A2 gene polymorphisms following a 6-week supplementation with fish oil

This clinical trial investigated the impact of a six-week supplementation with fish oil and single nucleotide polymorphisms (SNPs) in PLA2G4A and PLA2G6 genes on total omega-6 fatty acid (n-6 FA) levels in plasma phospholipids (PL) and plasma C-reactive protein (CRP) levels in 191 subjects. Interaction effects between SNPs and supplementation modulated total n-6 FAs and CRP levels in both men and women. Associations between SNPs and total n-6 FA levels and between SNPs and CRP levels were identified in men, independently of supplementation. Supplementation decreased total n-6 FAs without affecting plasma CRP levels. Changes in CRP levels correlated positively with changes in total n-6 FAs in men (r=0.25 p=0.01), but not in women. In conclusion, total n-6 FA levels in plasma PL and plasma CRP levels are modulated by SNPs within PLA2G4A and PLA2G6 genes alone or in combination with fish oil supplementation.

Interaction of SNP in the CRP gene and plasma fatty acid profile in inflammatory pattern: A cross-sectional population-based study

OBJECTIVE

To assess the interaction of three single nucleotide polymorphisms in the C-reactive protein (CRP) gene and plasma fatty acid (FA) levels in modulating inflammatory profile.

METHODS

A total of 262 subjects, aged >19 y and <60 y, participated in a cross-sectional, population-based study performed in Brazil. Three single nucleotide polymorphisms (rs1205, rs1417938, and rs2808630) spanning the CRP gene were genotyped. Eleven plasma inflammatory biomarkers and plasma FA profile were determined. Cluster analysis was performed to stratify individuals based on eleven inflammatory biomarkers into two groups: an inflammatory (INF) and a noninflammatory group.

RESULTS

The INF cluster had higher age, waist circumference, systolic blood pressure, and diastolic blood pressure; higher levels of triacylglycerol, high-sensitivity CRP, tumor necrosis factor-α, interleukin (IL)-8, IL-6, IL-1β, IL-12, IL-10, soluble monocyte chemoattractant protein-1, soluble intercellular adhesion molecule-1, C16:0, polyunsaturated fatty acid, and omega (n)-6 polyunsaturated fatty acid; and greater C20:4n-6, C18:1/18:0, and C20:4/20:3 ratios than the noninflammatory group. Statistically significant gene-plasma C16:1n-7 interaction was detected for rs1417938 (P = 0.047). Those with a dominant homozygous rs2808630 had a lower risk of belonging to the INF group with the upper 50th percentile of C20:4n-6, n-3 highly unsaturated FA, and C20:4/20:3 ratio. Regarding rs1205, A allele carriers had lower risk of being in the INF group when C20:5n-3 and n-3 highly unsaturated FA levels were greater than the median.

CONCLUSIONS

The INF group exhibited changes in metabolic parameters that predispose this group to chronic disease, where polymorphisms in the CRP gene modulated the risk of being in the INF group depending on individual plasma fatty acid and lipid profile.

Metabolomics Reveals Metabolically Healthy and Unhealthy Obese Individuals Differ in their Response to a Caloric Challenge

OBJECTIVE

To determine if metabolically healthy obese (MHO) individuals have a different metabolic response to a standardized diet compared to lean healthy (LH) and metabolically unhealthy obese (MUO) individuals.

METHODS

Thirty adults (35-70 yrs) were classified as LH, MHO, and MUO according to anthropometric and clinical measurements. Participants consumed a standardized high calorie meal (~1330 kcal). Blood glucose and insulin were measured at fasting, and 15, 30, 60, 90 and 120 min postprandially. Additional blood samples were collected for the targeted analysis of amino acids (AAs) and derivatives, and fatty acids (FAs).

RESULTS

The postprandial response (i.e., area under the curve, AUC) for serum glucose and insulin were similar between MHO and LH individuals, and significantly lower than MUO individuals (p < 0.05). Minor differences were found in postprandial responses for AAs between MHO and MUO individuals, while three polyunsaturated FAs (linoleic acid, γ-linolenic acid, arachidonic acid) showed smaller changes in serum after the meal in MHO individuals compared to MUO. Fasting levels for various AAs (notably branched-chain AA) and FAs (e.g., saturated myristic and palmitic acids) were found to correlate with glucose and insulin AUC.

CONCLUSION

MHO individuals show preserved insulin sensitivity and a greater ability to adapt to a caloric challenge compared to MUO individuals.

Plasma fatty acid composition in French-Canadian children with non-alcoholic fatty liver disease: Effect of n-3 PUFA supplementation

Non-alcoholic fatty liver disease (NAFLD) represents one of the most common causes of liver disease worldwide. As the NAFLD pathogenesis is associated with diet and lifestyle, the aims of the present work are to assess fatty acid (FA) composition in NAFLD young French-Canadian, to determine whether treatment with n-3 FA improves the plasma FA profile, and to define the time on the effectiveness of n-3 FA supplementation. Baseline characteristics of the NAFLD subjects show increased, anthropometric and biochemical parameters. Their plasma FA composition is characterized by a percent increase in total n-6 FA and a high proportion of saturated and total monounsaturated FA, as well as a decrease in Δ5 and increase in Δ6 desaturases. In conclusion, our results document for the first time the composition of plasma FAs in NAFLD young French Canadian and the efficacy of 3-month supplementation to improve the proportion of n-3 FA in their plasma.

Associations of dairy intake with glycemia and insulinemia, independent of obesity, in Brazilian adults: the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

BACKGROUND

Inverse associations between dairy intake and the risk of type 2 diabetes have been shown, but more studies are needed, especially from low- and middle-income countries.

OBJECTIVE

The objective was to describe the association between dairy products and direct measures of glycemic status in adults without known diabetes.

DESIGN

The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) includes 15,105 adults, aged 35-74 y, enrolled from universities and research institutions in 6 Brazilian capital cities. We excluded participants with a known diabetes diagnosis, cardiovascular diseases, and cancer. Dairy consumption was assessed by a food-frequency questionnaire, and we computed servings per day for total and subgroups of dairy. Associations with fasting blood glucose (FG) and fasting insulin, 2-h postload glucose (PG), 2-h postload insulin (PI), glycated hemoglobin (Hb A1c), and homeostasis model assessment of insulin resistance (HOMA-IR) were assessed through multivariable linear regression analysis with adjustment for demographic characteristics, behavioral risk factors, other dietary factors, and anthropometric measurements.

RESULTS

The sample size after exclusions was 10,010. The intake of total dairy was inversely associated with FG (linear β for dairy servings/d = -0.46 ± 0.2 mg/dL), PG (-1.25 ± 0.5 mg/dL), PI (-1.52 ± 0.6 mg/dL), Hb A1c (-0.02 ± 0.0%), and HOMA-IR (-0.04 ± 0.0) after adjustment for all covariates (P < 0.05 for all). The findings were consistent across categories of sex, race, obesity status, and dairy fat amount (reduced-fat vs. full-fat dairy). Fermented dairy products showed particularly strong inverse associations with the outcomes, with adjusted differences for a 1-serving/d increment of -0.24 (95% CI: -0.46, -0.02) mg/dL for FG, -0.86 (-1.42, -0.30) mg/dL for PG, and -0.01% (-0.02%, 0.00%) for Hb A1c. Myristic acid was the only nutrient that appeared to mediate the association between dairy intake and glycemia.

CONCLUSION

Dairy intake, especially fermented dairy, was inversely associated with measures of glycemia and insulinemia in Brazilian adults without diagnosed diabetes. This trial was registered at clinicaltrials.com as NCT02320461.

Association between circulating thrombopoietin levels and cardiovascular risk prediction scores in renal transplant recipients

BACKGROUND/AIMS

The 7-year Major Adverse Cardiovascular Events Calculator (CRCRTR-MACE) predicts cardiovascular events (CVE) in renal transplant recipients (RTR), and thrombopoietin (TPO) is a humoral inflammatory factor implicated in cardiovascular disease (CVD). The aim of the study was to determine if circulating TPO levels in stable RTR are positively associated with variable(s) in the CRCRTR-MACE score.

METHODS

CRCRTR-MACE scores were calculated in 95 stable RTR. TPO levels were measured by multiplexed fluorescent bead-based immunoassay in all patients and 48 controls. Multivariate analysis (MVA) was performed between TPO and CV risk variables and patient demographics. Stepwise regression with backward elimination of insignificant variables estimated the impact of risk variables on TPO levels. Significance was defined at p < 0.05. Normalized data were presented as mean ± SD and non-normalized data as median (maximum to minimum).

RESULTS

The risk of a CVE within 7 years as predicted by the median was 9.97% (range 1.93-84.2). The percentage of patients who were above 20% risk for a CVE was 28.4%. Control TPO level of 170.41 (4.4-995.9) pg/ml was significantly lower than that of 237.90 (32.77-1,386.79) pg/ml in RTR (p = 0.010). TPO level correlated significantly with the total CRCRTR-MACE score (R = 0.310, p = 0.004), smoking (p = 0.009) and eGFR (R = -0.275, p = 0.012) but not with age, diabetes, LDL level or history of CVE. Only the total CRCRTR-MACE score (p = 0.013) and smoking (p = 0.009) remained significant in the MVA. Stepwise regression estimated that smoking increased TPO levels by 206.28 pg/ml and each 10% increase in CRCRTR-MACE score increased TPO levels by an additional 44.4 pg/ml.

CONCLUSION

TPO levels are increased in RTR with high CRCRTR-MACE, particularly in smokers with diminished eGFR. Circulating TPO may serve as a biomarker and treatment target for CVD in RTR.

Fatty acids, lipid mediators, and T-cell function

Research toward the mechanisms underlying obesity-linked complications has intensified during the last years. As a consequence, it has become clear that metabolism and immunity are intimately linked. Free fatty acids and other lipids acquired in excess by current feeding patterns have been proposed to mediate this link due to their immune modulatory capacity. The functional differences between saturated and unsaturated fatty acids, in combination with their dietary intake are believed to modulate the outcome of immune responses. Moreover, unsaturated fatty acids can be oxidized in a tightly regulated and specific manner to generate either potent pro-inflammatory or pro-resolving lipid mediators. These oxidative derivatives of fatty acids have received detailed attention during the last years, as they have proven to have strong immune modulatory capacity, even in pM ranges. Both fatty acids and oxidized fatty acids have been studied especially in relation to macrophage and T-cells functions. In this review, we propose to focus on the effect of fatty acids and their oxidative derivatives on T-cells, as it is an active area of research during the past 5 years. The effect of fatty acids and their derivatives on activation and proliferation of T-cells, as well as the delicate balance between stimulation and lipotoxicity will be discussed. Moreover, the receptors involved in the interaction between free fatty acids and their derivatives with T-cells will be summarized. Finally, the mechanisms involved in modulation of T-cells by fatty acids will be addressed, including cellular signaling and metabolism of T-cells. The in vitro results will be placed in context of in vivo studies both in humans and mice. In this review, we summarize the latest findings on the immune modulatory function of lipids on T-cells and will point out novel directions for future research.

Fatty acid status and its relationship to cognitive decline and homocysteine levels in the elderly

Polyunsaturated fatty acids (PUFAs), especially the n-3 series, are known for their protective effects. Considering that cardiovascular diseases are risk factors for dementia, which is common at aging, the aim of this study was to evaluate whether fatty acid status in the elderly was associated with cognitive function and cardiovascular risk. Forty-five elderly persons (age ≥60 years) were included and divided into two groups based on their Mini-Mental Status Examination score adjusted for educational level: the case group (n = 12) and the control group (n = 33). Serum fatty acid composition, homocysteine (Hcy), hs-CRP, lipid profile and different cognitive domains were evaluated. The case group, characterized by reduced cognitive performance, showed higher levels of 14:0, 16:0, 16:1n-7 fatty acids and lower levels of 22:0, 24:1n-9, 22:6n-3 (DHA) and total PUFAs compared to the control group (p < 0.05). The n-6/n-3 ratio was elevated in both study groups, whereas alterations in Hcy, hs-CRP and lipid profile were observed in the case group. Cognitive function was positively associated with the 24:1n-9, DHA and total n-3 PUFAs, while 14:0, 16:0 and 16:1n-7 fatty acids, the n-6/n-3 ratio and Hcy were inversely associated. In addition, n-3 PUFAs, particularly DHA, were inversely associated with cardiovascular risk, assessed by Hcy levels in the elderly.