FADS1 and FADS2 Gene Polymorphisms Modulate the Relationship of Omega-3 and Omega-6 Fatty Acid Plasma Concentrations in Gestational Weight Gain: A NISAMI Cohort Study

Effects of the rs174575 single nucleotide polymorphism in FADS2 on levels of long-chain PUFA: a meta-analysis

The influence of the SNP rs174575 (C/G) within the fatty acid desaturase 2 gene on the levels of long-chain PUFA was determined through statistical meta-analysis. Six databases were searched to retrieve the relevant literature. Original data were analysed using Stata 17·0, encompassing summary statistics, tests for heterogeneity, assessment of publication bias, subgroup analysis and sensitivity analysis. A total of ten studies were identified and grouped into twelve trials. Our results showed that individuals who carried the minor G allele of rs174575 had significantly higher dihomo-γ-linolenic acid levels (P = 0·005) and lower arachidonic acid levels (P = 0·033) than individuals who were homozygous for the major allele. The subgroup analysis revealed that the G-allele carriers of rs174575 were significantly positively correlated with linoleic acid (P = 0·002) and dihomo-γ-linolenic acid (P < 0·001) and negatively correlated with arachidonic acid (P = 0·004) in the European populations group. This particular SNP showed a potential association with higher concentrations of dihomo-γ-linolenic acid (P = 0·050) and lower concentrations of arachidonic acid (P = 0·030) within the breast milk group. This meta-analysis has been registered in the PROSPERO database (ID: CRD42023470562).

Effect of FADS1 SNPs rs174546, rs174547 and rs174550 on blood fatty acid profiles and plasma free oxylipins

Introduction

Previous studies have indicated that activity of fatty acid desaturase 1 (FADS1), is involved in cardiometabolic risk. Recent experimental data have shown that FADS1 knockdown can promote lipid accumulation and lipid droplet formation in liver cells. In this study, we aimed to characterize whether different FADS1 genotypes affect liver fat content, essential fatty acid content and free oxylipin mediators in the blood.

Methods

We analyzed the impact of FADS1 single-nucleotide polymorphisms (SNPs) rs174546, rs174547, and rs174550 on blood fatty acids and free oxylipins in a cohort of 85 patients from an academic metabolic medicine outpatient center. Patients were grouped based on their genotype into the homozygous major (derived) allele group, the heterozygous allele group, and the homozygous minor (ancestral) allele group. Omega-3 polyunsaturated fatty acids (n-3 PUFA) and omega-6 polyunsaturated fatty acids (n-6 PUFA) in the blood cell and plasma samples were analyzed by gas chromatography. Free Oxylipins in plasma samples were analyzed using HPLC-MS/MS. Liver fat content and fibrosis were evaluated using Fibroscan technology.

Results

Patients with the homozygous ancestral (minor) FADS1 genotype exhibited significantly lower blood levels of the n-6 PUFA arachidonic acid (AA), but no significant differences in the n-3 PUFAs eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). There were no significant differences in liver fat content or arachidonic acid-derived lipid mediators, such as thromboxane B2 (TXB2), although there was a trend toward lower levels in the homozygous ancestral genotype group.

Discussion

Our findings suggest that FADS1 genotypes influence the blood levels of n-6 PUFAs, while not significantly affecting the n-3 PUFAs EPA and DHA. The lack of significant differences in liver fat content and arachidonic acid-derived lipid mediators suggests that the genotype-related variations in fatty acid levels may not directly translate to differences in liver fat or inflammatory lipid mediators in this cohort. However, the trend towards lower levels of certain lipid mediators in the homozygous ancestral genotype group warrants further investigation to elucidate the underlying mechanisms of different FADS1 genotypes and potential implications for cardiometabolic risk.

Genetic correlation between circulating metabolites and chalazion: a two-sample Mendelian randomization study

Background: Lipid metabolism disorders were observationally associated with chalazion, but the causality of the related circulating metabolites on chalazion remained unknown. Here, we investigated the potential causal relationship between circulating metabolites and chalazion using two-sample Mendelian randomization (MR) analysis. Methods: For the primary analysis, 249 metabolic biomarkers were obtained from the UK Biobank, and 123 circulating metabolites were obtained from the publication by Kuttunen et al. for the secondary analysis. Chalazion summary data were obtained from the FinnGen database. Inverse variance weighted (IVW) is the main MR analysis method, and the MR assumptions were evaluated in sensitivity and colocalization analyses. Results: Two MR analyses results showed that the common metabolite, alanine, exhibited a genetic protective effect against chalazion (primary analysis: odds ratio [OR] = 0.680; 95% confidence interval [CI], 0.507-0.912; p = 0.010; secondary analysis: OR = 0.578; 95% CI, 0.439-0.759; p = 0.00008). The robustness of the findings was supported by heterogeneity and horizontal pleiotropy analysis. Two colocalization analyses showed that alanine did not share a region of genetic variation with chalazion (primary analysis: PPH4 = 1.95%; secondary analysis: PPH4 = 25.3%). Moreover, previous studies have suggested that an increase in the degree of unsaturation is associated with an elevated risk of chalazion (OR = 1.216; 95% CI, 1.055-1.401; p = 0.007), with omega-3 fatty acids (OR = 1.204; 95% CI, 1.054-1.377; p = 0.006) appearing to be the major contributing factor, as opposed to omega-6 fatty acids (OR = 0.850; 95% CI, 0.735-0.982; p = 0.027). Conclusion: This study suggests that alanine and several unsaturated fatty acids are candidate molecules for mechanistic exploration and drug target selection in chalazion.

Gestational Weight Gain: Is the Role of Genetic Variants a Determinant? A Review

Excessive or insufficient gestational weight gain (GWG) leads to diverse adverse maternal and neonatal outcomes. There is evidence that pregestational body mass index (pBMI) plays a role in GWG, but no genetic cause has been identified. In this review, we aim to analyze genotype variants associated with GWG. Results: We identified seven genotype variants that may be involved in GWG regulation that were analyzed in studies carried out in Brazil, Romania, the USA, Turkey, Ukraine, and Canada. Some genetic variants were only associated with GWG in certain races or depending on the pBMI. In women who were obese or overweight before gestation, some genetic variants were associated with GWG. Environmental and genetic factors together showed a greater association with GWG than genetic factors alone; for example, type of diet was observed to have a significant influence. Conclusions: We found little scientific evidence of an association between genotype variants in countries with a high prevalence of women of reproductive age who are overweight and obese, such as in Latin America. GWG may be more dependent on environmental factors than genetic variants. We suggest a deeper study of genetic variants, cytokines, and their possible association with GWG, always with the respective control of potential cofounding factors, such as pBMI, diet, and race.

Immunogenetic Aspects of Sarcopenic Obesity

Sarcopenic obesity (SO) is a combination of obesity and sarcopenia, with diagnostic criteria defined as impaired skeletal muscle function and altered body composition (e.g., increased fat mass and reduced muscle mass). The mechanism of SO is not yet perfectly understood; however, the pathogenesis includes aging and its complications, chronic inflammation, insulin resistance (IR), and hormonal changes. Genetic background is apparent in the pathogenesis of isolated obesity, which is most often polygenic and is characterized by the additive effect of various genetic factors. The genetic etiology has not been strictly established in SO. Still, many data confirm the existence of pathogenic gene variants, e.g., Fat Mass and Obesity Associated Gene (FTO), beta-2-adrenergic receptor (ADRB2) gene, melanocortin-4 receptor (MC4R) and others with obesity. The literature on the role of these genes is scarce, and their role has not yet been thoroughly established. On the other hand, the involvement of systemic inflammation due to increased adipose tissue in SO plays a significant role in its pathophysiology through the synthesis of various cytokines such as monocyte chemoattractant protein-1 (MCP-1), IL-1Ra, IL-15, adiponectin or CRP. The lack of anti-inflammatory cytokine (e.g., IL-15) can increase SO risk, but further studies are needed to evaluate the exact mechanisms of implications of various cytokines in SO individuals. This manuscript analyses various immunogenetic and non-genetic factors and summarizes the recent findings on immunogenetics potentially impacting SO development.

Transcriptome and proteomics conjoint analysis reveal anti-alcoholic liver injury effect of Dianhong Black Tea volatile substances

Dianhong Black Tea, a fermented tea containing various bioactive ingredients, has been found to have a significant role in alleviating alcoholic liver injury (ALI). One of its main unique components, Dianhong Black Tea volatile substances (DBTVS), may have potential anti-ALI effects. However, its effects and underlying molecular mechanisms are still unknown. In this study, we aimed to investigate the potential of DBTVS as an anti-ALI agent using alcohol-fed rats. We assessed the effect of DBTVS on ALI by analyzing serum transaminase and lipid levels, as well as conducting hematoxylin-eosin and oil red O staining. Additionally, GC-MS was used to detect the components of DBTVS, while transcriptome, proteomics analysis, Western blot, and molecular docking were employed to uncover the underlying mechanisms. Our results demonstrated that DBTVS significantly reduced serum ALT and AST levels and improved lipid metabolism disorders. Moreover, we identified 14 components in DBTVS, with five of them exhibiting strong binding affinity with key proteins. These findings suggested that DBTVS could be a promising agent for the prevention and treatment of ALI. Its potential therapeutic effects may be attributed to its ability to regulate lipid metabolism through the PPAR signaling pathway.

Rumen microbial-driven metabolite from grazing lambs potentially regulates body fatty acid metabolism by lipid-related genes in liver

BACKGROUND

Lipid metabolism differs significantly between grazing and stall-feeding lambs, affecting the quality of livestock products. As two critical organs of lipid metabolism, the differences between feeding patterns on rumen and liver metabolism remain unclear. In this study, 16S rRNA, metagenomics, transcriptomics, and untargeted metabolomics were utilized to investigate the key rumen microorganisms and metabolites, as well as liver genes and metabolites associated with fatty acid metabolism under indoor feeding (F) and grazing (G).

RESULTS

Compared with grazing, indoor feeding increased ruminal propionate content. Using metagenome sequencing in combination with 16S rRNA amplicon sequencing, the results showed that the abundance of propionate-producing Succiniclasticum and hydrogenating bacteria Tenericutes was enriched in the F group. For rumen metabolism, grazing caused up-regulation of EPA, DHA and oleic acid and down-regulation of decanoic acid, as well as, screening for 2-ketobutyric acid as a vital differential metabolite, which was enriched in the propionate metabolism pathway. In the liver, indoor feeding increased 3-hydroxypropanoate and citric acid content, causing changes in propionate metabolism and citrate cycle, while decreasing the ETA content. Then, the liver transcriptome revealed that 11 lipid-related genes were differentially expressed in the two feeding patterns. Correlation analysis showed that the expression of CYP4A6, FADS1, FADS2, ALDH6A1 and CYP2C23 was significantly associated with the propionate metabolism process, suggesting that propionate metabolism may be an important factor mediating the hepatic lipid metabolism. Besides, the unsaturated fatty acids in muscle, rumen and liver also had a close correlation.

CONCLUSIONS

Overall, our data demonstrated that rumen microbial-driven metabolite from grazing lambs potentially regulates multiple hepatic lipid-related genes, ultimately affecting body fatty acid metabolism.

Association of Fatty Acid Desaturase 1 rs174547 Polymorphism with the Composition of Long-Chain Polyunsaturated Fatty Acids in Serum Glycerophospholipids during Pregnancy

The increase in fetal requirements of long-chain polyunsaturated fatty acids (LCPUFAs) during pregnancy alters maternal fatty acid metabolism, and therefore, fatty acid desaturase (FADS) gene polymorphisms may change blood fatty acid composition or concentration differently during pregnancy. We investigated the relationship between a FADS1 single-nucleotide polymorphism (SNP) and maternal serum LCPUFA levels in Japanese pregnant women during the first and third trimesters and at delivery. Two hundred and fifty-three pregnant women were included, and fatty acid compositions of glycerophospholipids in serum (weight %) and the FADS1 SNP rs174547 (T/C) were analyzed. LCPUFAs, including arachidonic acid (ARA) and docosahexaenoic acid (DHA), significantly decreased from the first to the third trimester of pregnancy. Furthermore, DHA significantly decreased from the third trimester of pregnancy to delivery. At all gestational stages, linoleic acid (LA) and α-linolenic acid were significantly higher with the number of minor FADS1 SNP alleles, whereas γ-linolenic acid and ARA and the ARA/LA ratio were significantly lower. DHA was significantly lower with the number of minor FADS1 SNP alleles only in the third trimester and at delivery, suggesting that genotype effects become more obvious as pregnancy progresses.

Genetics, genomics, and diet interactions in obesity in the Latin American environment

Obesity is a chronic disease characterized by abnormal or excessive fat accumulation that could impact an individual's health; moreover, the World Health Organization (WHO) has declared obesity a global epidemic since 1997. In Latin America, in 2016, reports indicated that 24.2% of the adult population was obese. The environmental factor or specific behaviors like dietary intake or physical activity have a vital role in the development of a condition like obesity, but the interaction of genes could contribute to that predisposition. Hence, it is vital to understand the relationship between genes and disease. Indeed, genetics in nutrition studies the genetic variations and their effect on dietary response; while genomics in nutrition studies the role of nutrients in gene expression. The present review represents a compendium of the dietary behaviors in the Latin American environment and the interactions of genes with their single nucleotide polymorphisms (SNPs) associated with obesity, including the risk allele frequencies in the Latin American population. Additionally, a bibliographical selection of several studies has been included; these studies examined the impact that dietary patterns in Latin American environments have on the expression of numerous genes involved in obesity-associated metabolic pathways.

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.