Genome-Wide Association Study for Serum Omega-3 and Omega-6 Polyunsaturated Fatty Acids: Exploratory Analysis of the Sex-Specific Effects and Dietary Modulation in Mediterranean Subjects with Metabolic Syndrome

Dietary, macronutrient, micronutrient, and nutrigenetic factors impacting cardiovascular risk markers apolipoprotein B and apolipoprotein A1: a narrative review

Genetic predisposition and dietary factors can impact cardiovascular disease (CVD) risk. Two important markers in assessing CVD risk are apolipoprotein (apo) B and apolipoprotein A1 plasma levels. These markers are measured as a ratio, with a high apoB:apoA1 ratio associated with increased CVD risk. Dietary and lifestyle recommendations are the cornerstone of managing primary and secondary CVD risk-mitigation strategies. One way to assess the impact of various dietary and lifestyle interventions on CVD risk is to evaluate the changes in CVD risk markers, such as apoB, apoA1, and apoB:apoA1 ratio. Various human studies have demonstrated the impact of dietary, macronutrient, and micronutrient interventions on apoB and apoA1 status. This review aims to elucidate dietary, macronutrient, micronutrient, and nutrigenetic considerations for impacting apoB and apoA1 levels. A low-carbohydrate, high-saturated-fat diet, low fiber intake, low vitamin and mineral intake, and zinc and iron deficiency are associated with an elevated apoB:apoA1 ratio. The Mediterranean diet, vegan diet, fermented dairy products, lower sugar intake, higher protein intake, higher polyunsaturated fat intake, and an omega-3-rich diet are associated with a decreased apoB:apoA1 ratio. Micronutrients associated with a decreased apoB:apoA1 ratio include vitamin D sufficiency, increased serum vitamin C, and magnesium. Variants in the APOE, APOA1, and FADS2 genes may alter the apoB:apoA1 ratio in response to various dietary interventions. When accounting for factors that may favorably alter the apoB:apoA1 ratio, researchers should consider a healthy diet sufficient in polyunsaturated fats, vitamins, minerals, trace minerals, and lower excess sugars.

Genetic association between FADS and ELOVL polymorphisms and the circulating levels of EPA/DHA in humans: a scoping review

BACKGROUND

Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are two omega-3 fatty acids that can be synthesized out of their precursor alpha-linolenic acid (ALA). FADS and ELOVL genes encode the desaturase and elongase enzymes required for EPA and DHA synthesis from ALA; however, single nucleotide polymorphisms (SNPs) in FADS and ELOVL genes could modify the levels of EPA and DHA synthesized from ALA although there is no consensus in this area. This review aims to investigate EPA and DHA circulating levels in human blood and their association with FADS or ELOVL.

METHODS

PubMed, Cochrane, and Scopus databases were used to identify research articles. They were subsequently reviewed by two independent investigators.

RESULTS

Initially, 353 papers were identified. After removing duplicates and articles not meeting inclusion criteria, 98 full text papers were screened. Finally, this review included 40 studies investigating FADS and/or ELOVL polymorphisms. A total of 47 different SNPs in FADS genes were reported. FADS1 rs174537, rs174547, rs174556 and rs174561 were the most studied SNPs, with minor allele carriers having lower levels of EPA and DHA. SNPs in the FADS genes were in high linkage disequilibrium. SNPs in FADS were correlated with levels of EPA and DHA. No conclusion could be drawn with the ELOVL polymorphisms since the number of studies was too low.

CONCLUSION

Specific SNPs in FADS gene, such as rs174537, have strong associations with circulating levels of EPA and DHA. Continued investigation regarding the impact of genetic variants related to EPA and DHA synthesis is warranted.

Patterns of perinatal polyunsaturated fatty acid status and associated dietary or candidate-genetic factors

Perinatal exposure to omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) can be characterized through biomarkers in maternal or cord blood or breast milk. Objectives were to describe perinatal PUFA status combining multiple biofluids and to investigate how it was influenced by dietary intake during pregnancy and maternal FADS and ELOVL gene polymorphisms. This study involved 1,901 mother-child pairs from the EDEN cohort, with PUFA levels measured in maternal and cord erythrocytes, and colostrum. Maternal dietary PUFA intake during the last trimester was derived from a food frequency questionnaire. Twelve single-nucleotide polymorphisms in FADS and ELOVL genes were genotyped from maternal DNA. Principal component analysis incorporating PUFA levels from the three biofluids identified patterns of perinatal PUFA status. Spearman's correlations explored associations between patterns and PUFA dietary intake, and linear regression models examined pattern associations with FADS or ELOVL haplotypes. Five patterns were retained: "High omega-3 LC-PUFAs, low omega-6 LC-PUFAs"; "Omega-6 LC-PUFAs"; "Colostrum LC-PUFAs"; "Omega-6 precursor (LA) and DGLA"; "Omega-6 precursor and colostrum ALA". Maternal omega-3 LC-PUFA intakes were correlated with "High omega-3 LC-PUFAs, low omega-6 LC-PUFAs" (r(DHA) = 0.33) and "Omega-6 LC-PUFAs" (r(DHA) = -0.19) patterns. Strong associations were found between FADS haplotypes and PUFA patterns except for "High omega-3 LC-PUFAs, low omega-6 LC-PUFAs". Lack of genetic association with the "High omega-3 LC-PUFAs, low omega-6 LC-PUFAs" pattern, highly correlated with maternal omega-3 LC-PUFA intake, emphasizes the importance of adequate omega-3 LC-PUFA intake during pregnancy and lactation. This study offers a more comprehensive assessment of perinatal PUFA status and its determinants.

A Genome-Wide Interaction Study of Erythrocyte ω-3 Polyunsaturated Fatty Acid Species and Memory in the Framingham Heart Study Offspring Cohort

BACKGROUND

Cognitive decline, and more specifically Alzheimer's disease, continues to increase in prevalence globally, with few, if any, adequate preventative approaches. Several tests of cognition are utilized in the diagnosis of cognitive decline that assess executive function, short- and long-term memory, cognitive flexibility, and speech and motor control. Recent studies have separately investigated the genetic component of both cognitive health, using these measures, and circulating fatty acids.

OBJECTIVES

We aimed to examine the potential moderating effect of main species of ω-3 polyunsaturated fatty acids (PUFAs) on an individual's genetically conferred risk of cognitive decline.

METHODS

The Offspring cohort from the Framingham Heart Study was cross-sectionally analyzed in this genome-wide interaction study (GWIS). Our sample included all individuals with red blood cell ω-3 PUFA, genetic, cognitive testing (via Trail Making Tests [TMTs]), and covariate data (N = 1620). We used linear mixed effects models to predict each of the 3 cognitive measures (TMT A, TMT B, and TMT D) by each ω-3 PUFA, single nucleotide polymorphism (SNP) (0, 1, or 2 minor alleles), ω-3 PUFA by SNP interaction term, and adjusting for sex, age, education, APOE ε4 genotype status, and kinship (relatedness).

RESULTS

Our analysis identified 31 unique SNPs from 24 genes reaching an exploratory significance threshold of 1×10-5. Fourteen of the 24 genes have been previously associated with the brain/cognition, and 5 genes have been previously associated with circulating lipids. Importantly, 8 of the genes we identified, DAB1, SORCS2, SERINC5, OSBPL3, CPA6, DLG2, MUC19, and RGMA, have been associated with both cognition and circulating lipids. We identified 22 unique SNPs for which individuals with the minor alleles benefit substantially from increased ω-3 fatty acid concentrations and 9 unique SNPs for which the common homozygote benefits.

CONCLUSIONS

In this GWIS of ω-3 PUFA species on cognitive outcomes, we identified 8 unique genes with plausible biology suggesting individuals with specific polymorphisms may have greater potential to benefit from increased ω-3 PUFA intake. Additional replication in prospective settings with more diverse samples is needed.

Effects of saturated and monounsaturated fatty acids on cognitive impairment: evidence from Mendelian randomization study

BACKGROUND

Prior observational studies have suggested correlations between saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs) with cognitive function. However, causal relationships remains unclear.

METHODS

We assessed the causal impact of two SFAs (palmitic acid [PA] and stearic acid [SA]) and two MUFAs (oleic acid [OA] and palmitoleic acid [POA]) on cognitive function-related traits, and dementia-related traits by univariable Mendelian randomization (UVMR) and multivariable Mendelian randomization (MVMR) analyses.

RESULTS

UVMR indicated β of 0.060 (P = 4.05E-06) for cognitive performance score and 0.066 (P = 4.21E-04) for fluid intelligence per standard deviation (SD) increase in OA level. MVMR indicated: (i) β of -0.608 (P = 8.37E-05) for fluid intelligence score per SD increase in POA; (ii) β of 0.074 (P = 0.018) for fluid intelligence score per SD increase in OA; (iii) β of 0.029 (P = 0.033) for number of incorrect matches in round per SD increase in PA; and (iv) β of 0.039 (P = 0.032) for number of incorrect matches in round per SD increase in SA. In addition, a secondary MVMR analysis after excluding the effect of polyunsaturated fatty acids suggested that: (i) β of -0.043 (P = 1.97E-02) for cognitive performance score per SD increase in PA and (ii) β of -0.079 (P = 1.79E-03) for cognitive performance score per SD increase in SA.

CONCLUSIONS

Overall, UVMR and MVMR suggest that OA may be beneficial for cognitive function, while POA, PA, and SA may have detrimental effects on cognitive function.

The role of polyunsaturated fatty acids in the neurobiology of major depressive disorder and suicide risk

Long-chain polyunsaturated fatty acids (LC-PUFAs) are obtained from diet or derived from essential shorter-chain fatty acids, and are crucial for brain development and functioning. Fundamentally, LC-PUFAs' neurobiological effects derive from their physicochemical characteristics, including length and double bond configuration, which differentiate LC-PUFA species and give rise to functional differences between n(omega)-3 and n-6 LC-PUFAs. LC-PUFA imbalances are implicated in psychiatric disorders, including major depression and suicide risk. Dietary intake and genetic variants in enzymes involved in biosynthesis of LC-PUFAs from shorter chain fatty acids influence LC-PUFA status. Domains impacted by LC-PUFAs include 1) cell signaling, 2) inflammation, and 3) bioenergetics. 1) As major constituents of lipid bilayers, LC-PUFAs are determinants of cell membrane properties of viscosity and order, affecting lipid rafts, which play a role in regulation of membrane-bound proteins involved in cell-cell signaling, including monoaminergic receptors and transporters. 2) The n-3:n-6 LC-PUFA balance profoundly influences inflammation. Generally, metabolic products of n-6 LC-PUFAs (eicosanoids) are pro-inflammatory, while those of n-3 LC-PUFAs (docosanoids) participate in the resolution of inflammation. Additionally, n-3 LC-PUFAs suppress microglial activation and the ensuing proinflammatory cascade. 3) N-3 LC-PUFAs in the inner mitochondrial membrane affect oxidative stress, suppressing production of and scavenging reactive oxygen species (ROS), with neuroprotective benefits. Until now, this wealth of knowledge about LC-PUFA biomechanisms has not been adequately tapped to develop translational studies of LC-PUFA clinical effects in humans. Future studies integrating neurobiological mechanisms with clinical outcomes may suggest ways to identify depressed individuals most likely to respond to n-3 LC-PUFA supplementation, and mechanistic research may generate new treatment strategies.

Depletion of DNTTIP2 Induces Cell Cycle Arrest in Pancreatic Cancer Cells

BACKGROUND/AIM

Pancreatic cancer is one of the most lethal malignant cancers worldwide and the seventh most common cause of cancer-related death in both sexes. Herein, we analyzed open access data and discovered that expression of a gene called deoxynucleotidyltransferase terminal-interacting protein 2 (DNTTIP2) is linked to prognosis of pancreatic ductal adenocarcinoma (PDAC). We then elucidated the role of DNTTIP2 in the proliferation of pancreatic cancer cells in vitro.

MATERIALS AND METHODS

A WST-8 assay, cell cycle analysis, Annexin-V staining, quantitative reverse transcription-PCR, and western blot analysis were conducted to assess cell proliferation, cell cycle, apoptosis, and expression of DNTTIP2 mRNA and protein, respectively, in DNTTIP2-depleteted MIA-PaCa-2 and PK-1 cells.

RESULTS

Depletion of DNTTIP2 induced G1 arrest in MIA-PaCa-2 cells by decreasing expression of special AT-rich sequence binding protein 1 (SATB1) and cyclin-dependent kinase 6 (CDK6). In addition, depletion of DNTTIP2 induced G2 arrest in PK-1 cells by decreasing expression of CDK1. Depletion of DNTTIP2 did not induce apoptosis in MIA-PaCa-2 or PK-1 cells.

CONCLUSION

DNTTIP2 is involved in proliferation of pancreatic cancer cells. Thus, DNTTIP2 is a potential target for inhibiting progression of pancreatic cancers.

A Genome-Wide Association Study of Metabolic Syndrome in the Taiwanese Population

The purpose of this study was to investigate genetic factors associated with metabolic syndrome (MetS) by conducting a large-scale genome-wide association study (GWAS) in Taiwan, addressing the limited data on Asian populations compared to Western populations. Using data from the Taiwan Biobank, comprehensive clinical and genetic information from 107,230 Taiwanese individuals was analyzed. Genotyping data from the TWB1.0 and TWB2.0 chips, including over 650,000 single nucleotide polymorphisms (SNPs), were utilized. Genotype imputation using the 1000 Genomes Project was performed, resulting in more than 9 million SNPs. MetS was defined based on a modified version of the Adult Treatment Panel III criteria. Among all participants (mean age: 50 years), 23% met the MetS definition. GWAS analysis identified 549 SNPs significantly associated with MetS, collectively mapping to 10 genomic risk loci. Notable risk loci included rs1004558, rs3812316, rs326, rs4486200, rs2954038, rs10830963, rs662799, rs62033400, rs183130, and rs34342646. Gene-set analysis revealed 22 associated genes: CETP, LPL, APOA5, SIK3, ZPR1, APOC1, BUD13, MLXIPL, TOMM40, GCK, YKT6, RPS6KB1, FTO, VMP1, TUBD1, BCL7B, C19orf80 (ANGPTL8), SIDT2, SENP7, PAFAH1B2, DOCK6, and FOXA2. This study identified genomic risk loci for MetS in a large Taiwanese population through a comprehensive GWAS approach. These associations provide novel insights into the genetic basis of MetS and hold promise for the potential discovery of clinical biomarkers.

Effect of aerobic exercise alone or combined with Mediterranean diet on dry eye in obese hypertensive elderly

BACKGROUND

Lifestyle modification is a newly recommended complementary treatment for dry eye (DE) disorder.

OBJECTIVE

To investigate the effect of a 6-month high-intensity interval aerobic exercise (HIIAE) (conducted 30 min, 3 times weekly) alone or combined with a caloric-restriction approach, the Mediterranean diet (MD), on DE parameters in obese hypertensive elderly.

THE DESIGN, SETTINGS, PARTICIPANTS, AND INTERVENTION

This is a randomized controlled trial included sixty obese hypertensive elderly with DE based on university-based hospital recruitment. Elderly were randomly assigned to the experimental group (n = 30 elderly received HIIAE plus MD) and control group (n = 30 elderly received only HIIAE). Besides anthropometry (abdominal circumference, body weight, and body mass index) and blood pressure (measured in systole and diastole), DE parameters (tear film break-up time, DE scoring system, ocular surface disability index questionnaire, Schirmer's test, and Oxford grading system) were evaluated.

RESULTS

Significant improvements in anthropometry, blood pressure, and DE parameters were higher in the experimental group than in the control group.

CONCLUSION

Aging-related DE symptoms and signs can be prevented and/or treated with HIIAE alone or combined with MD in obese hypertensive elderly with DE disorder.

Meta-GWAS on PCSK9 concentrations reveals associations of novel loci outside the PCSK9 locus in White populations

BACKGROUND AND AIMS

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a key regulator of lipid homeostasis. A few earlier genome-wide association studies (GWAS) investigated genetic variants associated with circulating PCSK9 concentrations. However, uncertainty remains about some of the genetic loci discovered beyond the PCSK9 locus. By conducting the largest PCSK9 meta-analysis of GWAS (meta-GWAS) so far, we aimed to identify novel loci and validate the previously reported loci that regulate PCSK9 concentrations.

METHODS

We performed GWAS for PCSK9 concentrations in two large cohorts (GCKD (n = 4,963) and KORA F3 (n = 2,895)). These were meta-analyzed with previously published data encompassing together 20,579 individuals. We further conducted a second meta-analysis in statin-naïve individuals (n = 15,390). A genetic risk score (GRS) was constructed on PCSK9-increasing SNPs and assessed its impact on the risk for coronary artery disease (CAD) in 394,943 statin-naïve participants (17,077 with events) of the UK Biobank by performing CAD-free survival analysis.

RESULTS

Nine loci were genome-wide significantly associated with PCSK9 concentrations. These included the previously described PCSK9, APOB, KCNA1/KCNA5, and TM6SF2/SUGP1 loci. All imputed SNPs in the PCSK9 locus account for ∼15% of variance of PCSK9 concentrations. We further identified FADS2 as a novel locus that was also found in statin-naïve participants. All imputed SNPs within the FADS2 locus explain ∼1.2% of variance of PCSK9 concentrations. Additionally, four further loci (a region on chromosome 5, SDK1, SPATA16 and HPR) were genome-wide significant in either the main model or the statin-naïve subset. The linear increase in a PCSK9 genetic risk score was associated with 1.41-fold (95%CI 1.16-1.72, p < 0.001) higher risk for incident CAD.

CONCLUSIONS

We identified five novel loci (FADS2, SPATA16, SDK1, HPR and a region on chromosome 5) for PCSK9 concentrations that would require further research. Additionally, we confirm the genome-wide significant loci that were previously detected.

Associations between the New DNA-Methylation-Based Telomere Length Estimator, the Mediterranean Diet and Genetics in a Spanish Population at High Cardiovascular Risk

Biological aging is a relevant risk factor for chronic diseases, and several indicators for measuring this factor have been proposed, with telomere length (TL) among the most studied. Oxidative stress may regulate telomere shortening, which is implicated in the increased risk. Using a novel estimator for TL, we examined whether adherence to the Mediterranean diet (MedDiet), a highly antioxidant-rich dietary pattern, is associated with longer TL. We determined TL using DNA methylation algorithms (DNAmTL) in 414 subjects at high cardiovascular risk from Spain. Adherence to the MedDiet was assessed by a validated score, and genetic variants in candidate genes and at the genome-wide level were analyzed. We observed several significant associations (p < 0.05) between DNAmTL and candidate genes (TERT, TERF2, RTEL1, and DCAF4), contributing to the validity of DNAmTL as a biomarker in this population. Higher adherence to the MedDiet was associated with lower odds of having a shorter TL in the whole sample (OR = 0.93; 95% CI: 0.85-0.99; p = 0.049 after fully multivariate adjustment). Nevertheless, this association was stronger in women than in men. Likewise, in women, we observed a direct association between adherence to the MedDiet score and DNAmTL as a continuous variable (beta = 0.015; SE: 0.005; p = 0.003), indicating that a one-point increase in adherence was related to an average increase of 0.015 ± 0.005 kb in TL. Upon examination of specific dietary items within the global score, we found that fruits, fish, "sofrito", and whole grains exhibited the strongest associations in women. The novel score combining these items was significantly associated in the whole population. In the genome-wide association study (GWAS), we identified ten polymorphisms at the suggestive level of significance (p < 1 × 10-5) for DNAmTL (intergenics, in the IQSEC1, NCAPG2, and ABI3BP genes) and detected some gene-MedDiet modulations on DNAmTL. As this is the first study analyzing the DNAmTL estimator, genetics, and modulation by the MedDiet, more studies are needed to confirm these findings.

Omega-3 polygenic score protects against altered eating behavior in intrauterine growth-restricted children

BACKGROUND

Alterations in eating behavior are common in infants with intrauterine growth restriction (IUGR); omega-3 polyunsaturated fatty acids (PUFA) could provide protection. We hypothesized that those born IUGR with a genetic background associated with increased production of omega-3-PUFA will have more adaptive eating behaviors during childhood.

METHODS

IUGR/non-IUGR classified infants from MAVAN and GUSTO cohorts were included at the age of 4 and 5 years, respectively. Their parents reported child's eating behaviors using the child eating behavior questionnaire-CEBQ. Based on the GWAS on serum PUFA (Coltell 2020), three polygenic scores were calculated.

RESULTS

Significant interactions between IUGR and polygenic score for omega-3-PUFA on emotional overeating (β = -0.15, P = 0.049 GUSTO) and between IUGR and polygenic score for omega-6/omega-3-PUFA on desire to drink (β = 0.35, P = 0.044 MAVAN), pro-intake/anti-intake ratio (β = 0.10, P = 0.042 MAVAN), and emotional overeating (β = 0.16, P = 0.043 GUSTO) were found. Only in IUGR, a higher polygenic score for omega-3-PUFA associated with lower emotional overeating, while a higher polygenic score for omega-6/omega-3-PUFA ratio was associated with a higher desire to drink, emotional overeating, and pro-intake/anti-intake.

CONCLUSION

Only in IUGR, the genetic background for higher omega-3-PUFA is associated with protection against altered eating behavior, while the genetic score for a higher omega-6/omega-3-PUFA ratio is associated with altered eating behavior.

IMPACT

A genetic background related to a higher polygenic score for omega-3 PUFA protected infants born IUGR against eating behavior alterations, while a higher polygenic score for omega-6/omega-3 PUFA ratio increased the risk of having eating behavior alterations only in infants born IUGR, irrespective of their adiposity in childhood. Genetic individual differences modify the effect of being born IUGR on eating outcomes, increasing the vulnerability/resilience to eating disorders in IUGR group and likely contributing to their risk for developing metabolic diseases later in life.

Sex-specific responses in glucose-insulin homeostasis and lipoprotein-lipid components after high-dose supplementation with marine n-3 PUFAs in abdominal obesity: a randomized double-blind crossover study

Background

Clinical studies on effects of marine-derived omega-3 (n-3) polyunsaturated fatty acids (PUFAs), mainly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and the plant-derived omega-6 (n-6) PUFA linoleic acid (LA) on lipoprotein-lipid components and glucose-insulin homeostasis have shown conflicting results, which may partly be explained by differential responses in females and males. However, we have lacked data on sexual dimorphism in the response of cardiometabolic risk markers following increased consumption of n-3 or n-6 PUFAs.

Objective

To explore sex-specific responses after n-3 (EPA + DHA) or n-6 (LA) PUFA supplementation on circulating lipoprotein subfractions, standard lipids, apolipoproteins, fatty acids in red blood cell membranes, and markers of glycemic control/insulin sensitivity among people with abdominal obesity.

Methods

This was a randomized double-blind crossover study with two 7-week intervention periods separated by a 9-week washout phase. Females (n = 16) were supplemented with 3 g/d of EPA + DHA (fish oil) or 15 g/d of LA (safflower oil), while males (n = 23) received a dose of 4 g/d of EPA + DHA or 20 g/d of LA. In fasting blood samples, we measured lipoprotein particle subclasses, standard lipids, apolipoproteins, fatty acid profiles, and markers of glycemic control/insulin sensitivity.

Results

The between-sex difference in relative change scores was significant after n-3 for total high-density lipoproteins (females/males: -11%*/-3.3%, p = 0.036; *: significant within-sex change), high-density lipoprotein particle size (+2.1%*/-0.1%, p = 0.045), and arachidonic acid (-8.3%*/-12%*, p = 0.012), and after n-6 for total (+37%*/+2.1%, p = 0.041) and small very-low-density lipoproteins (+97%*/+14%, p = 0.021), and lipoprotein (a) (-16%*/+0.1%, p = 0.028). Circulating markers of glucose-insulin homeostasis differed significantly after n-3 for glucose (females/males: -2.1%/+3.9%*, p = 0.029), insulin (-31%*/+16%, p < 0.001), insulin C-peptide (-12%*/+13%*, p = 0.001), homeostasis model assessment of insulin resistance index 2 (-12%*/+14%*, p = 0.001) and insulin sensitivity index 2 (+14%*/-12%*, p = 0.001), and quantitative insulin sensitivity check index (+4.9%*/-3.4%*, p < 0.001).

Conclusion

We found sex-specific responses after high-dose n-3 (but not n-6) supplementation in circulating markers of glycemic control/insulin sensitivity, which improved in females but worsened in males. This may partly be related to the sex differences we observed in several components of the lipoprotein-lipid profile following the n-3 intervention.

Clinical trial registration

https://clinicaltrials.gov/, identifier [NCT02647333].

A Genome-Wide Analysis of a Sudden Cardiac Death Cohort: Identifying Novel Target Variants in the Era of Molecular Autopsy

Sudden cardiac death (SCD) is an unexpected natural death due to cardiac causes, usually happening within one hour of symptom manifestation or in individuals in good health up to 24 h before the event. Genomic screening has been increasingly applied as a useful approach to detecting the genetic variants that potentially contribute to SCD and helping the evaluation of SCD cases in the post-mortem setting. Our aim was to identify the genetic markers associated with SCD, which might enable its target screening and prevention. In this scope, a case-control analysis through the post-mortem genome-wide screening of 30 autopsy cases was performed. We identified a high number of novel genetic variants associated with SCD, of which 25 polymorphisms were consistent with a previous link to cardiovascular diseases. We ascertained that many genes have been already linked to cardiovascular system functioning and diseases and that the metabolisms most implicated in SCD are the lipid, cholesterol, arachidonic acid, and drug metabolisms, suggesting their roles as potential risk factors. Overall, the genetic variants pinpointed herein might be useful markers of SCD, but the novelty of these results requires further investigations.

Association between circulating fatty acid metabolites and asthma risk: a two-sample bidirectional Mendelian randomization study

BACKGROUND

Fatty acids are involved in a wide range of immunological responses in humans. Supplementation of polyunsaturated fatty acids has been reported to help alleviate symptoms and airway inflammation in asthma patients, whereas the effects of fatty acids on the actual risk of asthma remain controversial. This study comprehensively investigated the causal effects of serum fatty acids on asthma risk using two-sample bidirectional Mendelian Randomization (MR) analysis.

METHODS

Genetic variants strongly associated with 123 circulating fatty acid metabolites were extracted as instrumental variables, and a large GWAS data of asthma was used to test effects of the metabolites on this outcome. The inverse-variance weighted method was used for primary MR analysis. The weighted median, MR-Egger regression, MR-PRESSO, and leave-one-out analyses were utilized to evaluate heterogeneity and pleiotropy. Potential confounders were adjusted by performing multivariable MR analyses. Reverse MR analysis was also conducted to estimate the causal effect of asthma on candidate fatty acid metabolites. Further, we performed colocalization analysis to examine the pleiotropy of variants within the fatty acid desaturase 1 (FADS1) locus between the significant metabolite traits and the risk of asthma. Cis-eQTL-MR and colocalization analysis were also performed to determine the association between RNA expression of FADS1 and asthma.

RESULTS

Genetically instrumented higher average number of methylene groups was causally associated with a lower risk of asthma in primary MR analysis, while inversely, the higher ratio of bis-allylic groups to double bonds and the higher ratio of bis-allylic groups to total fatty acids, were associated with higher probabilities of asthma. Consistent results were obtained in multivariable MR when adjusted for potential confounders. However, these effects were completely eliminated after SNPs correlated with the FADS1 gene were excluded. The reverse MR also found no causal association. The colocalization analysis suggested that the three candidate metabolite traits and asthma likely share causal variants within the FADS1 locus. In addition, the cis-eQTL-MR and colocalization analyses demonstrated a causal association and shared causal variants between FADS1 expression and asthma.

CONCLUSIONS

Our study supports a negative association between several PUFA traits and the risk of asthma. However, this association is largely attributed to the influence of FADS1 polymorphisms. The results of this MR study should be carefully interpreted given the pleiotropy of SNPs associated with FADS1.

Suppression of the human malic enzyme 2 modifies energy metabolism and inhibits cellular respiration

Human mitochondrial NAD(P)⁺-dependent malic enzyme (ME2) is well-known for its role in cell metabolism, which may be involved in cancer or epilepsy. We present potent ME2 inhibitors based on cyro-EM structures that target ME2 enzyme activity. Two structures of ME2-inhibitor complexes demonstrate that 5,5'-Methylenedisalicylic acid (MDSA) and embonic acid (EA) bind allosterically to ME2's fumarate-binding site. Mutagenesis studies demonstrate that Asn35 and the Gln64-Tyr562 network are required for both inhibitors' binding. ME2 overexpression increases pyruvate and NADH production while decreasing the cell's NAD⁺/NADH ratio; however, ME2 knockdown has the opposite effect. MDSA and EA inhibit pyruvate synthesis and thus increase the NAD⁺/NADH ratio, implying that these two inhibitors interfere with metabolic changes by inhibiting cellular ME2 activity. ME2 silence or inhibiting ME2 activity with MDSA or EA decreases cellular respiration and ATP synthesis. Our findings suggest that ME2 is crucial for mitochondrial pyruvate and energy metabolism, as well as cellular respiration, and that ME2 inhibitors could be useful in the treatment of cancer or other diseases that involve these processes.

DNA-Methylation Signatures of Tobacco Smoking in a High Cardiovascular Risk Population: Modulation by the Mediterranean Diet

Biomarkers based on DNA methylation are relevant in the field of environmental health for precision health. Although tobacco smoking is one of the factors with a strong and consistent impact on DNA methylation, there are very few studies analyzing its methylation signature in southern European populations and none examining its modulation by the Mediterranean diet at the epigenome-wide level. We examined blood methylation smoking signatures on the EPIC 850 K array in this population (n = 414 high cardiovascular risk subjects). Epigenome-wide methylation studies (EWASs) were performed analyzing differential methylation CpG sites by smoking status (never, former, and current smokers) and the modulation by adherence to a Mediterranean diet score was explored. Gene-set enrichment analysis was performed for biological and functional interpretation. The predictive value of the top differentially methylated CpGs was analyzed using receiver operative curves. We characterized the DNA methylation signature of smoking in this Mediterranean population by identifying 46 differentially methylated CpGs at the EWAS level in the whole population. The strongest association was observed at the cg21566642 (p = 2.2 × 10-32) in the 2q37.1 region. We also detected other CpGs that have been consistently reported in prior research and discovered some novel differentially methylated CpG sites in subgroup analyses. In addition, we found distinct methylation profiles based on the adherence to the Mediterranean diet. Particularly, we obtained a significant interaction between smoking and diet modulating the cg5575921 methylation in the AHRR gene. In conclusion, we have characterized biomarkers of the methylation signature of tobacco smoking in this population, and suggest that the Mediterranean diet can increase methylation of certain hypomethylated sites.

New Advances in Metabolic Syndrome, from Prevention to Treatment: The Role of Diet and Food

The definition of metabolic syndrome (MetS) has undergone several changes over the years due to the difficulty in establishing universal criteria for it. Underlying the disorders related to MetS is almost invariably a pro-inflammatory state related to altered glucose metabolism, which could lead to elevated cardiovascular risk. Indeed, the complications closely related to MetS are cardiovascular diseases (CVDs) and type 2 diabetes (T2D). It has been observed that the predisposition to metabolic syndrome is modulated by complex interactions between human microbiota, genetic factors, and diet. This review provides a summary of the last decade of literature related to three principal aspects of MetS: (i) the syndrome's definition and classification, pathophysiology, and treatment approaches; (ii) prediction and diagnosis underlying the biomarkers identified by means of advanced methodologies (NMR, LC/GC-MS, and LC, LC-MS); and (iii) the role of foods and food components in prevention and/or treatment of MetS, demonstrating a possible role of specific foods intake in the development of MetS.

Maternal DHA-rich n-3 PUFAs supplementation interacts with FADS genotypes to influence the profiles of PUFAs in the colostrum among Chinese Han population: a birth cohort study

Background

The single nucleotide polymorphisms (SNPs) in the fatty acid desaturases and elongases might associate with the endogenous synthesis of polyunsaturated fatty acids (PUFAs). However, the related epidemiological evidence is still conflicting. So we aimed to clearly evaluate the interactions between maternal DHA-rich n-3 PUFAs supplementation and the known 26 SNPs on the profiles of PUFAs in the colostrum using a Chinese birth cohort.

Methods

Totally, 1050 healthy mother-infant pairs were enrolled in this study at gestational 6–8 weeks when they established their pregnancy files at Fuxing Hospital affiliated to Capital Medical University in Beijing from January to December 2018. Meanwhile, their venous blood samples were obtained for DNA extraction to detect the genotypes of SNPs in the Fads1, Fads2, Fads3, Elovl2 and Elovl5 using the Matrix-Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry. Then the colostrum samples were collected to determine the profiles of PUFAs by gas chromatography.

Results

Maternal DHA-rich n-3 PUFAs supplementation from the early and middle pregnancy could reduce the infant BMI at birth, and impact the profiles of PUFAs in the colostrum, as higher n-3 PUFAs (EPA, DHA, DHA/ALA and DHA/EPA), lower n-6 PUFAs (AA and AA/LA) and ∑-6/n-3ΣPUFAs. Moreover, there were significant correlations between multiple SNPs and the profiles of n-6 PUFAs (rs76996928 for LA, rs174550, rs174553 and rs174609 for AA, rs174550 and rs76996928 for AA/LA) and n-3 PUFAs in the colostrum (rs174448, rs174537, rs174550, rs174553, rs174598, rs3168072, rs174455 and rs174464 for ALA, rs174550, rs174553 and rs174598 for EPA, rs174455 and rs174464 for DHA, rs174448 and rs3168072 for DHA/EPA) using the multiple linear regressions by adjusting the maternal age, gestational week, mode of delivery, infant sex and BMI at birth, and all these above significant SNPs had the cumulative effects on the profiles of PUFAs. Furthermore, the pairwise comparisons also showed the meaningful interactions between maternal DHA-rich n-3 PUFAs supplementation and related genotypes of SNPs (rs76996928 for LA, rs174598 for EPA, rs174448 for DHA and DHA/EPA) on the contents of PUFAs in the colostrum.

Conclusions

Results from this birth cohort study proved that the pregnant women with the following SNPs such as Fads3 rs174455 T, Fads3 rs174464 A and Fads1 rs174448 G alleles should pay more attention on their exogenous DHA supplementation from the early and middle pregnancy for the blocked endogenous synthesis.

Trial registration: This study was approved by the Ethics Committee of Beijing Pediatric Research Institution, Beijing Children’s Hospital affiliated to Capital Medical University (2016–08), which was also registered at the website of http://www.chictr.org.cn/showproj.aspx?proj=4673 (No: ChiCTR-OCH-14004900).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12986-022-00683-3.

Interaction among dietary n-3 and n-6 polyunsaturated fatty acid intake, fatty acid desaturase 2 genetic variants, and low-density lipoprotein cholesterol levels in type 2 diabetes patients

AIMS/INTRODUCTION

Fatty acid desaturase (FADS) genetic polymorphisms are strongly correlated with the risk of dyslipidemia and cardiovascular disease. In this study, we examined the impact of FADS1 and FADS2 genetic variants on plasma lipid status, and assessed interactions between FADS genetic polymorphisms and plasma n-3/n-6 fatty acids regarding lipid status within a population of 816 Taiwanese patients with type 2 diabetes.

MATERIALS AND METHODS

Selected tag single-nucleotide polymorphisms (FADS1 rs174546 [T/C]; FADS2 rs174602 [A/G] and rs2072114 [A/G]) were genotyped (n = 816).

RESULTS

The distribution of genotypes were compared with reports publicly available in the Genome Aggregation Database for East Asian populations (https://gnomad.broadinstitute.org). In the subgroup of patients not taking lipid-lowering medications (n = 192), we observed that the G allele of FADS2 rs174602 was statistically significantly correlated with lower low-density lipoprotein cholesterol (LDL-C) concentrations (P = 0.001), whereas the G allele of rs2072114 was marginally associated with LDL-C concentrations (P = 0.091). Using a general linear model adjusted for confounding factors, statistically significant interactions (P = 0.016) between single-nucleotide polymorphisms in rs2072114 and a low alpha-linolenic acid (18:3n-3)/linoleic acid (18:2n-6) ratio; the G allele correlated with lower LDL-C levels among individuals with a low alpha-linolenic acid/linoleic acid ratio. Interaction between rs174602 single-nucleotide polymorphisms and low alpha-linolenic acid/linoleic acid values on LDL-C was only marginally significant (P = 0.063).

CONCLUSIONS

Our results show the role of n-3/n-6 dietary polyunsaturated fatty acids in modifying the effects of genetic susceptibility on lipoprotein concentrations in patients with type 2 diabetes. Our findings highlight the potential of interventions with dietary polyunsaturated fatty acids regarding developing individualized prevention strategies for type 2 diabetes presenting with co-occurring dyslipidemia and cardiovascular diseases.

Evidence that complement and coagulation proteins are mediating the clinical response to omega-3 fatty acids: A mass spectrometry-based investigation in subjects at clinical high-risk for psychosis

Preliminary evidence indicates beneficial effects of omega-3 polyunsaturated fatty acids (PUFAs) in early psychosis. The present study investigates the molecular mechanism of omega-3 PUFA-associated therapeutic effects in clinical high-risk (CHR) participants. Plasma samples of 126 CHR psychosis participants at baseline and 6-months follow-up were included. Plasma protein levels were quantified using mass spectrometry and erythrocyte omega-3 PUFA levels were quantified using gas chromatography. We examined the relationship between change in polyunsaturated PUFAs (between baseline and 6-month follow-up) and follow-up plasma proteins. Using mediation analysis, we investigated whether plasma proteins mediated the relationship between change in omega-3 PUFAs and clinical outcomes. A 6-months change in omega-3 PUFAs was associated with 24 plasma proteins at follow-up. Pathway analysis revealed the complement and coagulation pathway as the main biological pathway to be associated with change in omega-3 PUFAs. Moreover, complement and coagulation pathway proteins significantly mediated the relationship between change in omega-3 PUFAs and clinical outcome at follow-up. The inflammatory protein complement C5 and protein S100A9 negatively mediated the relationship between change in omega-3 PUFAs and positive symptom severity, while C5 positively mediated the relationship between change in omega-3 and functional outcome. The relationship between change in omega-3 PUFAs and cognition was positively mediated through coagulation factor V and complement protein C1QB. Our findings provide evidence for a longitudinal association of omega-3 PUFAs with complement and coagulation protein changes in the blood. Further, the results suggest that an increase in omega-3 PUFAs decreases symptom severity and improves cognition in the CHR state through modulating effects of complement and coagulation proteins.

Personalized nutrition: A review of genotype-based nutritional supplementation

Nutritional disorders have become a major public health issue, requiring increased targeted approaches. Personalized nutrition adapted to individual needs has garnered dramatic attention as an effective way to improve nutritional balance and maintain health. With the rapidly evolving fields of genomics and nutrigenetics, accumulation of genetic variants has been indicated to alter the effects of nutritional supplementation, suggesting its indispensable role in the genotype-based personalized nutrition. Additionally, the metabolism of nutrients, such as lipids, especially omega-3 polyunsaturated fatty acids, glucose, vitamin A, folic acid, vitamin D, iron, and calcium could be effectively improved with related genetic variants. This review focuses on existing literatures linking critical genetic variants to the nutrient and the ways in which these variants influence the outcomes of certain nutritional supplementations. Although further studies are required in this direction, such evidence provides valuable insights for the guidance of appropriate interventions using genetic information, thus paving the way for the smooth transition of conventional generic approach to genotype-based personalized nutrition.

Fine-mapping and association analysis of candidate genes for papilla number in sea cucumber, Apostichopus japonicus

The papilla number is one of the most economically important traits of sea cucumber in the China marketing trade. However, the genetic basis for papilla number diversity in holothurians is still scarce. In the present study, we conducted genome-wide association studies (GWAS) for the trait papilla number of sea cucumbers utilizing a set of 400,186 high-quality SNPs derived from 200 sea cucumbers. Two significant trait-associated SNPs that passed Bonferroni correction (P < 1.25E-7) were located in the intergenic region near PATS1 and the genic region of EIF4G, which were reported to play a pivotal role in cell growth and proliferation. The fine-mapping regions around the top two lead SNPs provided precise causative loci/genes related to papilla formation and cellular activity, including PPP2R3C, GBP1, and BCAS3. Potential SNPs with P < 1E-4 were acquired for the following GO and KEGG enrichment analysis. Moreover, the two lead SNPs were verified in another population of sea cucumber, and the expressive detection of three potential candidate genes PATS1, PPP2R3C, and EIF4G that near or cover the two lead SNPs was conducted in papilla tissue of TG (Top papilla number group) and BG (Bottom papilla number group) by qRT-PCR. We found the significantly higher expression profile of PATS1 (3.34-fold), PPP2R3C (4.90-fold), and EIF4G (4.23-fold) in TG, implying their potential function in papilla polymorphism. The present results provide valuable information to decipher the phenotype differences of the papilla trait and will provide a scientific basis for selective breeding in sea cucumbers.

Supplementary Information

The online version contains supplementary material available at 10.1007/s42995-022-00139-w.

Association of Physical Activity With Bioactive Lipids and Cardiovascular Events

BACKGROUND

To clarify the mechanisms underlying physical activity (PA)-related cardioprotection, we examined the association of PA with plasma bioactive lipids (BALs) and cardiovascular disease (CVD) events. We additionally performed genome-wide associations.

METHODS

PA-bioactive lipid associations were examined in VITAL (VITamin D and OmegA-3 TriaL)-clinical translational science center (REGISTRATION: URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT01169259; N=1032) and validated in JUPITER (Justification for the Use of statins in Prevention: an Intervention Trial Evaluating Rosuvastatin)-NC (NCT00239681; N=589), using linear models adjusted for age, sex, race, low-density lipoprotein-cholesterol, total-C, and smoking. Significant BALs were carried over to examine associations with incident CVD in 2 nested CVD case-control studies: VITAL-CVD (741 case-control pairs) and JUPITER-CVD (415 case-control pairs; validation).

RESULTS

We detected 145 PA-bioactive lipid validated associations (false discovery rate <0.1). Annotations were found for 6 of these BALs: 12,13-diHOME, 9,10-diHOME, lysoPC(15:0), oxymorphone-3b-D-glucuronide, cortisone, and oleoyl-glycerol. Genetic analysis within JUPITER-NC showed associations of 32 PA-related BALs with 22 single-nucleotide polymorphisms. From PA-related BALs, 12 are associated with CVD.

CONCLUSIONS

We identified a PA-related bioactive lipidome profile out of which 12 BALs also had opposite associations with incident CVD events.

Δ5 and Δ6 desaturase indices are not associated with zinc intake as determined by dietary assessment or modified by a zinc-FADS1 rs174547 SNP interaction in young Canadian adults

BACKGROUND

Zinc is an essential trace mineral that serves as a cofactor for the delta-5 and delta-6 desaturases (D5D, D6D) that are critical for long-chain polyunsaturated fatty acid (LC-PUFA) synthesis. While plasma zinc levels are generally reported to be associated with D5D and D6D indices in humans, it remains unclear if dietary zinc intake can be similarly associated with desaturase indices. Therefore, the present investigation examined if zinc intake determined by food frequency questionnaire (FFQ) is associated with desaturase indices in young Canadian adults. Additionally, we explored whether desaturase indices were modified by an interaction between dietary zinc intake and a common variant in the FADS1 gene.

METHODS

Dietary zinc intake (FFQ), plasma fatty acids (gas chromatography) and the FADS1 rs174547 polymorphism were analyzed in young men and women (n = 803) from the cross-sectional Toronto Nutrigenomics and Health Study. Product-to-precursor fatty acid ratios were used to determine desaturase enzyme indices (D5D = 20:4n-6/20:3n-6; D6D = 18:3n-6/18:2n-6). Individuals were grouped according to dietary zinc intake, as well as by their rs174547 genotype (TT vs. TC+CC). Data were analyzed by 1-way and 2-way ANCOVA.

RESULTS

Plasma fatty acids and D5D/D6D indices did not differ between individuals grouped according to dietary zinc intake. Further, the recently proposed biomarker of zinc intake, 20:3n-6/18:2n-6, was not associated with dietary zinc intake. Although the FADS1 rs174547 SNP was significantly associated with D5D and D6D indices in both men and women (p < 0.0001), we did not find evidence of a dietary zinc intake - FADS1 SNP interaction on D5D or D6D indices.

CONCLUSION

Dietary zinc intake, as determined using FFQs, does not predict differences in desaturase indices, irrespective of FADS1 genotype.

“Big Data” Approaches for Prevention of the Metabolic Syndrome

Metabolic syndrome (MetS) is characterized by the concurrence of multiple metabolic disorders resulting in the increased risk of a variety of diseases related to disrupted metabolism homeostasis. The prevalence of MetS has reached a pandemic level worldwide. In recent years, extensive amount of data have been generated throughout the research targeted or related to the condition with techniques including high-throughput screening and artificial intelligence, and with these “big data”, the prevention of MetS could be pushed to an earlier stage with different data source, data mining tools and analytic tools at different levels. In this review we briefly summarize the recent advances in the study of “big data” applications in the three-level disease prevention for MetS, and illustrate how these technologies could contribute tobetter preventive strategies.

Genomic selection applications can improve the environmental performance of aquatics: a case study on the heat tolerance of abalone

Aquaculture is one of the world's fastest‐growing and most traded food industries, but it is under the threat of climate‐related risks represented by global warming, marine heatwave (MHW) events, ocean acidification, and deoxygenation. For the sustainable development of aquaculture, selective breeding may be a viable method to obtain aquatic economic species with greater tolerance to environmental stressors. In this study, we estimated the heritability of heat tolerance trait of Pacific abalone Haliotis discus hannai, performed genome‐wide association studies (GWAS) analysis for heat tolerance to detect single nucleotide polymorphisms (SNPs) and candidate genes, and assessed the potential of genomic selection (GS) in the breeding of abalone industry. A total of 1120 individuals were phenotyped for their heat tolerance and genotyped with 64,788 quality‐controlled SNPs. The heritability of heat tolerance was moderate (0.35–0.42) and the predictive accuracy estimated using BayesB (0.55 ± 0.05) was higher than that using GBLUP (0.40 ± 0.01). A total of 11 genome‐wide significant SNPs and 2 suggestive SNPs were associated with heat tolerance of abalone, and 13 candidate genes were identified, including got2,znfx1,l(2)efl, and lrp5. Based on GWAS results, the prediction accuracy using the top 5K SNPs was higher than that using randomly selected SNPs and higher than that using all SNPs. These results suggest that GS is an efficient approach for improving the heat tolerance of abalone and pave the way for abalone selecting breeding programs in rapidly changing oceans.

Mediterranean Diet and Genetic Determinants of Obesity and Metabolic Syndrome in European Children and Adolescents

Childhood obesity and metabolic syndrome (MetS) are multifactorial diseases influenced by genetic and environmental factors. The Mediterranean Diet (MD) seems to modulate the genetic predisposition to obesity or MetS in European adults. The FTO gene has also been shown to have an impact on the MD benefits to avoid obesity or MetS. Since these interaction effects have been scarcely analyzed in European youth, the aim was to describe the gene–MD interplay, analyzing the impact of the genetic factors to reduce the obesity and MetS risk through MD adherence, and the MD impact in the obesity and MetS genetic profile. From the limited evidence on gene–MD interaction studies in European youth, a study showed that the influence of high MD adherence on adiposity and MetS was only observed with a limited number of risk alleles; the gene–MD interplay showed sex-specific differences, being higher in females. Most results analyzed in European adults elucidate that, the relationship between MD adherence and both obesity and MetS risk, could be modulated by obesity genetic variants and vice versa. Further research is needed, to better understand the inter-individual differences in the association between MD and body composition, and the integration of omics and personalized nutrition considering MD.

Appraisal of Gene-Environment Interactions in GWAS for Evidence-Based Precision Nutrition Implementation

PURPOSE OF REVIEW

This review aims to analyse the currently reported gene-environment (G × E) interactions in genome-wide association studies (GWAS), involving environmental factors such as lifestyle and dietary habits related to metabolic syndrome phenotypes. For this purpose, the present manuscript reviews the available GWAS registered on the GWAS Catalog reporting the interaction between environmental factors and metabolic syndrome traits.

RECENT FINDINGS

Advances in omics-related analytical and computational approaches in recent years have led to a better understanding of the biological processes underlying these G × E interactions. A total of 42 GWAS were analysed, reporting over 300 loci interacting with environmental factors. Alcohol consumption, sleep time, smoking habit and physical activity were the most studied environmental factors with significant G × E interactions. The implementation of more comprehensive GWAS will provide a better understanding of the metabolic processes that determine individual responses to environmental exposures and their association with the development of chronic diseases such as obesity and the metabolic syndrome. This will facilitate the development of precision approaches for better prevention, management and treatment of these diseases.

Possible antidepressant mechanisms of omega-3 polyunsaturated fatty acids acting on the central nervous system

Omega-3 polyunsaturated fatty acids (PUFAs) can play important roles in maintaining mental health and resistance to stress, and omega-3 PUFAs supplementation can display beneficial effects on both the prevention and treatment of depressive disorders. Although the underlying mechanisms are still unclear, accumulated evidence indicates that omega-3 PUFAs can exhibit pleiotropic effects on the neural structure and function. Thus, they play fundamental roles in brain activities involved in the mood regulation. Since depressive symptoms have been assumed to be of central origin, this review aims to summarize the recently published studies to identify the potential neurobiological mechanisms underlying the anti-depressant effects of omega-3 PUFAs. These include that of (1) anti-neuroinflammatory; (2) hypothalamus-pituitary-adrenal (HPA) axis; (3) anti-oxidative stress; (4) anti-neurodegeneration; (5) neuroplasticity and synaptic plasticity; and (6) modulation of neurotransmitter systems. Despite many lines of evidence have hinted that these mechanisms may co-exist and work in concert to produce anti-depressive effects, the potentially multiple sites of action of omega-3 PUFAs need to be fully established. We also discussed the limitations of current studies and suggest future directions for preclinical and translational research in this field.

Associations Of Delta Fatty Acid Desaturase Gene Polymorphisms With Lipid Metabolism Disorders

Overweight, obesity, type 2 diabetes mellitus, metabolic syndrome, cardiovascular diseases, and non-alcoholic fatty liver disease are common chronic ailments associated with lipid metabolism disorders. One of the mechanisms of these disorders is related to the deficiency and/or change in the balance of essential fatty acids (FAs). At the same time, the provision of ω3 and ω6 polyunsaturated fatty acids (PUFAs) depends, besides sufficient dietary intake, on efficiency of their endogenous biosynthesis by desaturation and elongation processes regulated by FA elongases and FA desaturases. Desaturases are encoded by PUFA desaturase genes (FADSs): FADS1 and FADS2. Alteration of FA desaturase activity and single nucleotide polymorphisms (SNPs) in the FADS1 and FADS2 gene cluster are associated with lipid metabolism dysfunction and may affect the pathogenesis of lipid-related diseases. People of different ages, from different ethnic backgrounds and countries may exhibit varying degrees of response to dietary supplements of ω3 and ω6 PUFAs. The study of the relationship between lipid metabolism disorders and genetic factors controlling FA metabolism is an important research area since the health effects of alimentary ω3 and ω6 PUFAs can depend on genetic variants of the FADS genes. This review summarizes the literature data on the association of FADS gene polymorphisms with lipid metabolism disorders and their role in the development of chronic non-communicable pathologies associated with changes in lipid metabolism.

FADS1 gene polymorphism(s) and fatty acid composition of serum lipids in adolescents

Polyunsaturated fatty acids (PUFA) influence many physiological functions. Associations have been found between single nucleotide polymorphisms (SNP) in the FADS1 (Fatty acid desaturase 1) gene and the relative abundance of PUFA in serum lipids. This study examines the relationship between two SNPs in the FADS1 gene (rs174546, rs174537) and the fatty acid (FA) composition of serum lipids in adolescents (13-18 years). We used DNA samples (670 children; 336 girls and 334 boys) from the Childhood Obesity Prevalence and Treatment (COPAT) project. Genomic DNA was extracted from peripheral blood leukocytes in whole blood samples. For genotype analysis, TaqMan SNP Genotyping assays (Applied Biosystems) were used. Fatty acid composition of serum lipids was assessed using gas chromatography. The T-statistic and regression were used for statistical evaluations. Minor allele T carriers in both SNPs had significant lower level of palmitic acid (16:0, phospholipids) and arachidonic acid (20:4[n-6], phospholipids) in both sexes. In girls, we found a significant positive association between minor allele T carriers and eicosadienoic acid (20:2[n-6], cholesteryl esters) in both SNPs. Being a minor allele T carrier was significantly positively associated with dihomo-γ-linolenic acid (20:3[n-6], phospholipids) in boys in both SNPs. SNPs (including rs174546, rs174537) in the FADS gene cluster should have impacted desaturase activity, which may contribute to different efficiency of PUFA synthesis.

Integrating lipidomics and genomics: emerging tools to understand cardiovascular diseases

Cardiovascular diseases (CVDs) are the leading cause of mortality and morbidity worldwide leading to 31% of all global deaths. Early prediction and prevention could greatly reduce the enormous socio-economic burden posed by CVDs. Plasma lipids have been at the center stage of the prediction and prevention strategies for CVDs that have mostly relied on traditional lipids (total cholesterol, total triglycerides, HDL-C and LDL-C). The tremendous advancement in the field of lipidomics in last two decades has facilitated the research efforts to unravel the metabolic dysregulation in CVDs and their genetic determinants, enabling the understanding of pathophysiological mechanisms and identification of predictive biomarkers, beyond traditional lipids. This review presents an overview of the application of lipidomics in epidemiological and genetic studies and their contributions to the current understanding of the field. We review findings of these studies and discuss examples that demonstrates the potential of lipidomics in revealing new biology not captured by traditional lipids and lipoprotein measurements. The promising findings from these studies have raised new opportunities in the fields of personalized and predictive medicine for CVDs. The review further discusses prospects of integrating emerging genomics tools with the high-dimensional lipidome to move forward from the statistical associations towards biological understanding, therapeutic target development and risk prediction. We believe that integrating genomics with lipidome holds a great potential but further advancements in statistical and computational tools are needed to handle the high-dimensional and correlated lipidome.

Single nucleotide variants lead to dysregulation of the human mitochondrial NAD(P)+-dependent malic enzyme

Human mitochondrial NAD(P)⁺-dependent malic enzyme (ME2) is well recognized to associate with cancer cell metabolism, and the single nucleotide variants (SNVs) of ME2 may play a role in enzyme regulation. Here we reported that the SNVs of ME2 occurring in the allosteric sites lead to inactivation or overactivation of ME2. Two ME2-SNVs, ME2_R67Q and ME2-R484W, that demonstrated inactivating or overactivating enzyme activities of ME2, respectively, have different impact toward the cells. The cells with overactivating SNV enzyme, ME2_R484W, grow more rapidly and are more resistant to cellular senescence than the cells with wild-type or inactivating SNV enzyme, ME2_R67Q. Crystal structures of these two ME2-SNVs reveal that ME2_R67Q was an inactivating "dead form," and ME2_R484W was an overactivating "closed form" of the enzyme. The resolved ME2-SNV structures provide a molecular basis to explain the abnormal kinetic properties of these SNV enzymes.

Circulating Adiponectin and Its Association with Metabolic Traits and Type 2 Diabetes: Gene-Diet Interactions Focusing on Selected Gene Variants and at the Genome-Wide Level in High-Cardiovascular Risk Mediterranean Subjects

Adiponectin is gaining renewed interest since, in addition to its possible protective role against insulin resistance and arteriosclerosis, recent studies suggest other additional favorable effects. However, the influence of gene-diet interactions on plasma adiponectin levels is still little understood. We analyzed the association between plasma adiponectin levels and various metabolic traits in a high-cardiovascular risk Mediterranean population, as well as the genetic effect of four candidate single-nucleotide polymorphisms (SNPs) in the adiponectin gene (ADIPOQ) and their interactions with the Mediterranean dietary pattern. Additionally, we explored, at the genome-wide level, the SNPs most associated with plasma adiponectin levels, as well as gene-diet interactions with the Mediterranean diet. In the 954 participants studied (aged 55-80 years), plasma adiponectin levels were strongly associated with plasma HDL-C concentrations (p = 6.6 × 10^-36) and inversely related to triglycerides (p = 4.7 × 10^-18), fasting glucose (p = 3.5 × 10^-16) and type 2 diabetes (p = 1.4 × 10^-7). Of the four pre-selected ADIPOQ candidate SNPs, the one most associated with plasma adiponectin was the -11391G > A (rs17300539) promoter SNP (p = 7.2 × 10^-5, in the multivariable adjusted model). No significant interactions with the Mediterranean diet pattern were observed for these SNPs. Additionally, in the exploratory genome-wide association study (GWAS), we found new SNPs associated with adiponectin concentrations at the suggestive genome-wide level (p < 1 × 10^-5) for the whole population, including the lead SNP rs9738548 (intergenic) and rs11647294 in the VAT1L (Vesicle Amine Transport 1 Like) gene. We also found other promising SNPs on exploring different strata such as men, women, diabetics and non-diabetics (p = 3.5 × 10^-8 for rs2850066). Similarly, we explored gene-Mediterranean diet interactions at the GWAS level and identified several SNPs with gene-diet interactions at p < 1 × 10^-5. A remarkable gene-diet interaction was revealed for the rs2917570 SNP in the OPCML (Opioid Binding Protein/Cell Adhesion Molecule Like) gene, previously reported to be associated with adiponectin levels in some populations. Our results suggest that, in this high-cardiovascular risk Mediterranean population, and even though adiponectin is favorably associated with metabolic traits and lower type 2 diabetes, the gene variants more associated with adiponectin may be population-specific, and some suggestive gene-Mediterranean diet interactions were detected.

Omega-3 polyunsaturated fatty acids focusing on eicosapentaenoic acid and docosahexaenoic acid in the prevention of cardiovascular diseases: a review of the state-of-the-art

INTRODUCTION

: An epidemiological study of Greenlandic Inuit suggested the importance of omega-3 polyunsaturated fatty acids (PUFAs) in preventing ischemic heart disease. After this landmark study, large-scale epidemiological studies have examined the benefits of omega-3 PUFAs in the prevention of cardiovascular diseases.

AREAS COVERED

: This article reviews studies on omega-3 PUFAs, and identifies issues relevant to cardiovascular risk.

EXPERT OPINION

: Recent studies have focused on the anti-inflammatory effects of omega-3 PUFAs and specialized pro-resolving mediators. High-purity eicosapentaenoic acid (EPA) ethyl ester and EPA/docosahexaenoic acid (DHA) preparations have been developed primarily for the treatment of hypertriglyceridemia. Various trials on the cardiovascular protective effects of omega-3 PUFAs have been reported, but the results have not been consistent. Some issues of the trials have been suggested, such as using low-dose omega-3 PUFAs and not including hypertriglyceridemia in subject selection criteria. REDUCE-IT study that used a high dose of high-purity EPA preparation showed a relative reduction in cardiovascular events, but, the STRENGTH study that used a high dose of EPA/DHA preparation did not support this benefit. This article reviews the roles of omega-3 PUFAs in cardiovascular diseases, including progress in understanding the molecular mechanisms and recent large-scale clinical trials.

Polyunsaturated fatty acid biosynthesis pathway and genetics. implications for interindividual variability in prothrombotic, inflammatory conditions such as COVID-19✰,✰✰,★,★★

COVID-19 symptoms vary from silence to rapid death, the latter mediated by both a cytokine storm and a thrombotic storm. SARS-CoV (2003) induces Cox-2, catalyzing the synthesis, from highly unsaturated fatty acids (HUFA), of eicosanoids and docosanoids that mediate both inflammation and thrombosis. HUFA balance between arachidonic acid (AA) and other HUFA is a likely determinant of net signaling to induce a healthy or runaway physiological response. AA levels are determined by a non-protein coding regulatory polymorphisms that mostly affect the expression of FADS1, located in the FADS gene cluster on chromosome 11. Major and minor haplotypes in Europeans, and a specific functional insertion-deletion (Indel), rs66698963, consistently show major differences in circulating AA (>50%) and in the balance between AA and other HUFA (47-84%) in free living humans; the indel is evolutionarily selective, probably based on diet. The pattern of fatty acid responses is fully consistent with specific genetic modulation of desaturation at the FADS1-mediated 20:3→20:4 step. Well established principles of net tissue HUFA levels indicate that the high linoleic acid and low alpha-linoleic acid in populations drive the net balance of HUFA for any individual. We predict that fast desaturators (insertion allele at rs66698963; major haplotype in Europeans) are predisposed to higher risk and pathological responses to SARS-CoV-2 could be reduced with high dose omega-3 HUFA.

Very Long Chain Marine n-3 Polyunsaturated Fatty Acids in Atherothrombotic Heart Disease. A Brief Review, with a Focus on Metabolic Effects

The global burden of atherothrombotic heart disease should be considered as a life-style disorder where differences in dietary habits and related risk factors like limited physical activity and adiposity together play important roles. Related metabolic changes have been scientifically elucidated in recent decades, and the role of the very-long-chain marine fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been much focused on, especially their possible effects on processes like inflammation and thrombosis. In the present brief review of related metabolic mechanisms, the effects of these fatty acids in a clinical setting have been referred to, including some of the authors' work on this topic. The main focus is the divergent results in the field and the important differences between the study population, the type of supplements and fresh marine sources, the proportion of EPA versus DHA dosages, and the duration of supplementation in clinical trials. We conclude that daily intake of at least 1 g of EPA + DHA may improve a dysmetabolic state in the population. The potential to reduce the risk and progression of atherothrombotic heart disease is still a matter of debate.

FADS2 polymorphisms are associated with plasma arachidonic acid and estimated desaturase-5 activity in a cross-sectional study

Polymorphisms in FADS genes are associated with plasma long-chain polyunsaturated fatty acids (LC-PUFA) and modulate omega-6/omega-3 balance. We hypothesized that the FADS2 gene variants will be associated with lower product-to-precursor ratio in the fatty acid metabolic pathways. Thus, we explored FADS2 rs174593, rs174616, and rs174576 effects on plasma phospholipid fatty acid profile, markers of desaturase activities, and risk factors in a sample of apparently healthy Serbian adults. Food and nutrient intake data were compiled through 24 h recalls. Plasma phospholipid fatty acid content was assessed by gas-chromatography. Estimated desaturase activities were calculated as conversion rates towards LC-PUFA in omega-6 pathway. During the selection of FADS2 polymorphisms, we accounted for their positional and functional aspect. Genotyping was performed by Real-Time PCR. Multivariable-adjusted general linear and hierarchical regression models were applied. Study subjects (mean age = 40 ± 7 years, 70% who were overweight) had a median dietary omega-6/omega-3 ratio of 16.29. Alternative allele frequencies were 33%, 36%, and 51% for rs174593, rs174576, and rs174616, respectively. Addition of FADS2 alternative alleles was associated with lower plasma arachidonic acid (AA, C20:4 n-6, P < .001) and estimated desaturase-5 activity (P < .001), irrespective of gender, age, daily polyunsaturated/saturated fatty acid intake, and obesity. The rs174576 association with AA withstood multiple testing and additional adjustments for other variants (multivariable-adjusted β = -1.14 [95% CI: -2.25, -0.43]). None of the variants was associated with dietary intake, serum lipids, or obesity. We observed inverse associations between FADS2 variants and plasma AA but not omega-3 fatty acids in Serbian subjects, with rs174576 exhibiting the strongest relation.

Maternal High Linoleic Acid Alters Placental Fatty Acid Composition

Fetal development is modulated by maternal nutrition during pregnancy. The dietary intake of linoleic acid (LA), an essential dietary n-6 polyunsaturated fatty acid (PUFA), has increased. We previously published that increased LA consumption during pregnancy does not alter offspring or placental weight but fetal plasma fatty acid composition; the developing fetus obtains their required PUFA from the maternal circulation. However, it is unknown if increased maternal linoleic acid alters placental fatty acid storage, metabolism, transport, and general placental function. Female Wistar-Kyoto rats were fed either a low LA diet (LLA; 1.44% of energy from LA) or high LA diet (HLA; 6.21% of energy from LA) for 10 weeks before pregnancy and during gestation. Rats were sacrificed at embryonic day 20 (E20, term = 22 days) and placentae collected. The labyrinth of placentae from one male and one female fetus from each litter were analyzed. High maternal LA consumption increased placental total n-6 and LA concentrations, and decreased total n-3 PUFA, alpha-linolenic acid (ALA), and docosahexaenoic acid (DHA). Fatty acid desaturase 1 (Fads1), angiopoietin-like 4 (Angptl4), and diacylglycerol lipase beta (Daglb) mRNA were downregulated in placentae from offspring from HLA dams. Maternal high LA downregulated the fatty acid transport protein 4 (Fatp4) and glucose transporter 1 (Slc2a1) mRNA in placentae. IL-7 and IL-10 protein were decreased in placentae from offspring from HLA dams. In conclusion, a high maternal LA diet alters the placental fatty acid composition, inflammatory proteins, and expressions of nutrient transporters, which may program deleterious outcomes in offspring.