Methylenetetrahydrofolate reductase variants associated with hypertension and cardiovascular disease interact with dietary polyunsaturated fatty acids to modulate plasma homocysteine in puerto rican adults

PUFA, genotypes and risk for cardiovascular disease

Polyunsaturated fatty acids (PUFAs) are long chain fatty acids that are characterized by the presence of more than one double bond. These include fatty acids such as ꞷ-3-α-linolenic acid (ALA) and ꞷ-6 -linoleic acid (LA) which can only be obtained from dietary sources and are therefore termed essential fatty acids. They contain the building blocks for dihomo-γ-linolenic acid and arachidonic acid in the ꞷ-6 family as well as eicosapentaenoic acid and docosahexaenoic acid in the ꞷ-3 family. Both ALA and LA are important constituents of animal and plant cell membranes and are important components of anti-inflammatory and pro-inflammatory hormones and therefore, often modulate cellular immunity under chronic inflammatory states. The variation in physiological PUFA levels is under significant genetic influence, the fatty acid desaturase (FADS) genes being key regulators of PUFA metabolism. These genetic variants have been shown to alter fatty acid metabolism and influence the onset and progression of various metabolic conditions. This detailed review discusses the role of PUFAs, diet and genotypes in risk for cardiovascular diseases.

Strong Correlation of MTHFR Gene Polymorphisms with Breast Cancer and its Prognostic Clinical Factors among Egyptian Females

Introduction:

Globally, Breast cancer (BC) is considered the second most common type of cancer and the principal cause of death among affected women. Aim: In this study, we targeted to demonstrate the association of MTHFR single gene polymorphisms (SNPs) with the susceptibility of breast cancer, in addition to its correlation with the clinical patient features.

Patients and Methods:

This work was conducted on 100 Egyptian females with breast cancer and 60 healthy matched controls. Clinical examinations and pathological investigations were recorded. Genotyping of MTHFR polymorphisms C677T (rs1801133) and A1298C (rs1801131) by using Restriction Fragment length Polymorphisms (RFLP) and Sequencing assays were performed. Univariate, Multivariate and Haplotype analysis for the allelic frequencies and the association with clinicopathological features of BC were assessed.

Results:

The present data showed a strong significant association between the CT and TT of MTHFR (C677T), and AC and CC of (A1289C) with the susceptibility of BC showing highly statistical P- value (0.001). It was also demonstrated that the most frequent haplotype of the two loci of MTHFR (rs1801133-rs1801131) was TC. The latter was strongly associated with the aggressive clinical features of each of tumor size, advanced stage, involvement of cancer in lymph nodes, overexpression of HER2neu and dual negativity of both ER and PR hormones.

Conclusions:

SNPs within the MTHFR gene (C677T) and (A1289C) have strong correlation with BC among Egyptian females; These SNPs should be considered as important prognostic markers for identifying the individuals at high risk of developing BC and its progression.

Effectiveness of community-based folate-oriented tertiary interventions on incidence of fetus and birth defects: a protocol for a single-blind cluster randomized controlled trial

BACKGROUND

Birth defects are the main cause of fetal death, infant mortality and morbidity worldwide. However, the etiology of birth defects remains largely unknown. Maternal folate status during periconception plays an important role in organogenesis and folic acid supplement reduces the risk of neural tube defects, congenital heart diseases, and several other birth defects. This trial seeks to evaluate the effectiveness of folate-oriented tertiary interventions during periconception on the incidence of fetus and birth defects.

METHODS

This is a single-blind, two-arm cluster randomized controlled trial in Shanghai, China. Eligible women from 22 clusters are recruited at pre-pregnancy physical examinations clinical settings. Compared to the routine perinatal care group (control arm), folate-oriented tertiary interventions will be provided to the intervention arm. The core interventions consist of assessments of folate status and metabolism, folate intake guidance, and re-evaluation of folate status to ensure red blood cell folate level above 400 ng/ml (906 nmol/L) before pregnancy. Screening and consulting of fetus and birth defects, and treatments of birth defects during pregnancy and afterward will be provided to both arms. The primary outcome is a composite incidence of fetus defects, stillbirth, and neonatal birth defects identified from the confirmation of pregnancy to 28 days after birth. Secondary outcomes include maternal and offspring adverse complications and cost-effectiveness of folate-oriented tertiary interventions. This protocol adheres to the SPIRIT Checklist.

DISCUSSION

To achieve the recommended folate status before or during pregnancy is still a challenge worldwide. This community-based cluster-randomized controlled intervention trial will evaluate the effectiveness of a package of interventions aiming at achieving recommended maternal folate status covering pre- and during pregnancy in reducing fetus and birth defects. Our study has the potential to improve the community-based practice of reducing modifiable risk factors of disease and improving primary prevention of the defects in China. The procedures would formulate the policy on folic acid supplementation during periconception against birth defects in primary care settings.

TRIAL REGISTRATION

Clinical Trial Registry, NCT03725878 . Prospectively registered on 31 October 2018.

Evidence on the causal link between homocysteine and hypertension from a meta-analysis of 40 173 individuals implementing Mendelian randomization

Numerous researchers have investigated the associations among methylenetetrahydrofolate reductase gene (MTHFR) C677T polymorphism, homocysteine (Hcy) concentration, and hypertension. However, the results are controversial. Thus, a meta-analysis implementing Mendelian randomization approach was conducted to examine the hypothesis that elevated Hcy concentration plausibly contributes to increased risk of hypertension. Based on several inclusion and exclusion criteria, eligible studies were selected to explore the correlation between MTHFR C677T and hypertension risk, MTHFR C677T and Hcy concentration in hypertension, and Hcy concentration and hypertension, and they were evaluated by odds ratios (ORs), effect size (ES), and standard mean difference with their corresponding 95% confidence intervals (95% CIs), respectively. Moreover, Mendelian randomization was implemented to evaluate the relationship between Hcy and hypertension. Consequently, 14 378 cases and 25 795 controls were involved in this study and the results showed that MTHFR C677T led to an elevated risk of hypertension (for T vs C: OR = 1.27, 95% CI = 1.17-1.37; for TT vs CC: OR = 1.53, 95% CI = 1.30-1.79). Additionally, in hypertensive subjects, the pooled Hcy concentration in individuals of TT genotype was 7.74 μmol/L (95% CI: 5.25-10.23) greater than that in individuals of CC genotype. Moreover, the pooled Hcy concentration in hypertensive was 0.69 μmol/L (95% CI: 0.50-0.87) greater than that in controls. The estimated causal OR associated with hypertension was 1.32 for 5 μmol/L Hcy increment. Via MTHFR C677T polymorphism, the findings in the present study demonstrated that there exists evidence on causal link between Hcy concentration and the risk of hypertension.

Plausible relationship between homocysteine and obesity risk via MTHFR gene: a meta-analysis of 38,317 individuals implementing Mendelian randomization

OBJECTIVE

Numerous studies have explored the role of methylenetetrahydrofolate reductase gene (MTHFR) C677T polymorphism and homocysteine (Hcy) concentration in obesity, but the results are inconsistent. Hence, we performed a meta-analysis implementing Mendelian randomization approach to test the assumption that the increased Hcy concentration is plausibly related to the elevated risk of obesity.

METHODS

Eligible studies were selected based on several inclusion and exclusion criteria. Correlations between MTHFR C677T and obesity risk, MTHFR C677T and Hcy concentration in obesity, Hcy concentration, and obesity were estimated by ORs, effect size and standard mean difference with their corresponding 95% CIs, respectively. Furthermore, Mendelian randomization analysis was performed to estimate the relationship between Hcy level and obesity.

RESULTS

Consequently, this meta-analysis implemented with Mendelian randomization approach was conducted among 8,622 cases and 29,695 controls. The results indicated that MTHFR C677T is associated with an increased risk of obesity (for T vs C: OR=1.06, 95% CI=1.02-1.10; for TT vs CC: OR=1.13, 95% CI=1.03-1.24). Moreover, in obese subjects, the pooled Hcy concentration in individuals of TT genotype was 2.91 mmol/L (95% CI: 0.27-5.55) higher than that in individuals of CC genotype. Furthermore, the pooled Hcy concentration in subjects with obesity was 0.74 mmol/L (95% CI: 0.36-1.12) higher than that in controls. The evaluated plausible OR associated with obesity was 1.23 for 5 μmol/L Hcy level increase.

CONCLUSIONS

Through this meta-analysis, we emphasize a strong relationship between Hcy level and obesity by virtue of MTHFR C677T polymorphism.

Association between plasma homocysteine and hypertension: Results from a cross-sectional and longitudinal analysis in Beijing's adult population from 2012 to 2017

Plasma homocysteine (Hcy) levels are associated with elevated blood pressure. However, the causal association between Hcy levels and the risk of hypertension remains ambiguous. Taking the study design effect into consideration, this study aimed to investigate this issue through a cross-sectional and longitudinal analysis. Data were obtained from the Beijing Health Management Cohort study, which conducted routine health check-ups from 2012 to 2017. Multivariate logistic regression was used for the cross-sectional analysis, and a quadratic inference function approach was performed for the longitudinal analysis. A total of 30 376 subjects (mean age = 50.0 years) were included in the cross-sectional analysis, and a subgroup of 3913 subjects without hypertension at baseline was included in the longitudinal analysis. After adjusting for potential confounders, the risk of hypertension increased with Hcy levels in the cross-sectional analysis using the traditional definition of hypertension (OR = 1.262, 95% CI: 1.155-1.378, Q2 vs Q1; OR = 1.458, 95% CI: 1.335-1.593, Q3 vs Q1; OR = 1.520, 95% CI: 1.388-1.664, Q4 vs Q1) and the 2017 hypertension definition (OR = 1.159, 95% CI: 1.067-1.259, Q2 vs Q1; OR = 1.328, 95% CI: 1.221-1.445, Q3 vs Q1; OR = 1.328, 95% CI: 1.217-1.449, Q4 vs Q1). The longitudinal analysis showed that hypertension risk increased in the third quartile of Hcy (OR = 1.268, 95% CI: 1.030-1.560, Q3 vs Q1). Elevated total plasma Hcy may be used as a predictive biomarker for hypertension. Attention should be paid to gender-specific mechanisms when issuing precise precautions.

Significant association between ERCC2 and MTHR polymorphisms and breast cancer susceptibility in Moroccan population: genotype and haplotype analysis in a case-control study

Background

Genetic determinants of breast cancer (BC) remained largely unknown in the majority of Moroccan patients. The purpose of this study was to explore the association of ERCC2 and MTHFR polymorphisms with genetic susceptibility to breast cancer in Moroccan population.

Methods

We genotyped ERCC2 polymorphisms (rs1799793 (G934A) and rs13181 (A2251C)) and MTHFR polymorphisms (rs1801133 (C677T) and rs1801131 (A1298C)) using TaqMan SNP Genotyping Assays. Genotypes were compared in 151 BC cases and 156 population-matched controls. Allelic, genotypic and haplotype associations with the risk and clinicopathological features of BC were assessed using logistic regression analyses.

Results

ERCC2-rs1799793-AA genotype was associated with high risk of BC compared to wild type genotype (recessive model: OR: 2.90, 95% CI: 1.34–6.26, p = 0.0069) even after Bonferroni correction (p < 0,0125). MTHFR rs1801133-TT genotype was associated with increased risk of BC (recessive model, OR: 2.49, 95% CI: 1.17–5.29, p = 0.017) but the association turned insignificant after Bonferroni correction. For the rest of SNPs, no statistical associations to BC risk were detected.

Significant association with clinical features was detected for MTHFR-rs1801133-TC genotype with early age at diagnosis and familial BC. Following Bonferroni correction, only association with familial BC remained significant. MTHFR-rs1801131-CC genotype was associated with sporadic BC. ERCC2-rs1799793-AA genotype correlated with ER+ and PR+ breast cancer. ERCC2-rs13181-CA genotype was significantly associated large tumors (T ≥ 3) in BC patients. None of these associations passed Bonferroni correction.

Haplotype analysis showed that ERCC2 A-C haplotype was significantly associated with increased BC risk (OR: 3.71, 95% CI: 1.7–8.12, p = 0.0002 and p = 0.0008 before and after Bonferroni correction, respectively) and positive expression of ER and PR in BC patients. ERCC2 G-C haplotype was correlated with PR negative and larger tumor (T4). We did not find any MTHFR haplotypes associated with BC susceptibility. However, the less common haplotype MTHFR T-C was more frequent in young patients and in familial breast cancer, while MTHFR C-C haplotype was associated with sporadic BC form.

Conclusions

Our findings are a first observation of association between ERCC2 SNPs and breast cancer in Moroccan population. The results suggested that ERCC2 and MTHFR polymorphisms may be reliable for assessing risk and prognosis of BC in Moroccan population.

The relationship between hyperhomocysteinemia and neurodegeneration

Homocysteine (Hcy) is a key junction in methionine metabolism. In inherited forms of hyperhomocysteinemia patients develop early vascular damage and cognitive decline. Hyperhomocysteinemia is a common consequence of dietary, behavioral and pathological conditions and is epidemiologically related to different diseases, among them neurodegenerative ones are receiving progressively more attention in the last years. Several detrimental mechanisms that see in Hcy a possible promoter seem to be implicated in neurodegeneration (protein structural and functional modifications, oxidative stress, cellular metabolic derangements, epigenetic modifications, pathological aggregates deposition, endothelial damage and atherothrombosis). Interventional studies exploring B group vitamins administration in terms of prevention of Hcy-related cognitive decline and cerebrovascular involvement have shown scant results. In this review, current and possible alternative/complementary approaches are discussed.

Polyunsaturated fatty acid intake and risk of cardiovascular mortality in a low fish-consuming population: a prospective cohort analysis

PURPOSE

The aim of this study was to examine the relationship between polyunsaturated fatty acids (PUFA) intake (n-6 and n-3) and mortality in a population-based sample with a low fish intake.

METHODS

Cox regression was used to examine the relationships between dietary PUFA intake and all-cause or CVD mortality in the Australian Diabetes, Obesity and Lifestyle Study (AusDiab) cohort, a population of 11,247 Australians aged ≥25 years recruited in 1999/2000 and followed until 2012. Demographic, lifestyle and behavioural information were collected by questionnaire and fasting blood tests undertaken. Dietary intake was collected by a 121-item food frequency questionnaire. Vital status and causes of death were collected by death registry linkage.

RESULTS

Those in the highest quintile of n-6 PUFA intake had lower risk of CVD mortality (HR 0.57, 95 % CI 0.38-0.86) after age and sex adjustment, but this failed to retain significance after further risk factor adjustment. Consumption of ≥1 serves/week of non-fried fish was associated with reduced risk of CVD mortality (HR 0.64, 95 % CI 0.45-0.91, p = 0.013) compared to those eating less than 1 serve/month, after sex and age adjustment, but did not retain significance after further adjustment. However, long-chain n-3 intake was not associated with CVD mortality, and those in the highest quintile of n-3 intake had a higher risk of all-cause mortality.

CONCLUSIONS

These findings do not support previous suggestions that n-6 PUFA have adverse effects on CVD risk. Greater intake of non-fried fish was associated with lower risk of CVD mortality, but those with the highest total n-3 intake were at slightly increased risk of all-cause mortality.

Two Mutations in the Caprine MTHFR 3'UTR Regulated by MicroRNAs Are Associated with Milk Production Traits

BACKGROUND

5,10-Methylenetetrahydrofolate reductase (MTHFR) plays a central role in folate metabolism by irreversibly converting 5,10-methylenetetrahydrofolate to 5-methylenetetrahydrofolate, a predominant circulating form of folate. Folate is reportedly important for milk protein synthesis, and MTHFR may be a key regulatory point of folate metabolism for milk protein synthesis in mammary epithelial cells. Prior to this study, polymorphisms of the MTHFR gene were not associated with milk production traits from a breeding perspective. Single nucleotide polymorphisms (SNPs) at microRNA (miRNA) binding sites (miR-SNPs) can affect gene expression. This study aimed to identify the effects of miR-SNPs (g.2244A>G and g.2264A>G) in the caprine MTHFR 3' UTR on the milk production traits of dairy goats.

RESULTS

Guanzhong dairy (GD, n = 325) goats were used to detect SNPs in the caprine MTHFR 3' UTR by DNA sequencing. Two novel SNPs (g.2244A>G and g.2264A>G) were identified in the said region. The homozygous haplotype A-G of the SNPs g.2244A>G and g.2264A>G was significantly associated with milk yield and milk protein levels in GD goats (P < 0.05). Functional assays indicated that the MTHFR 2244 A → G substitution could increase the binding activity of hsa-miR-1266 with the MTHFR 3' UTR. The MTHFR 2264 A → G substitution could decrease the binding activity of hsa-miR-616 with the MTHFR 3' UTR. In addition, we observed a significant increase in the MTHFR mRNA levels of homozygous haplotype A-G carriers relative to those of homozygous haplotype G-A carriers. These results indicated that both SNPs altered the MTHFR mRNA levels. These altered levels of MTHFR mRNA may account for the association of SNPs with milk production traits.

CONCLUSIONS

This study is the first to report that the g.2244A>G and g.2264A>G polymorphisms were associated with milk production traits in GD goats. Further investigations should explore the underlying miRNA-mediated mechanisms that are modified by the g.2244A>G and g.2264A>G SNPs. The current study evaluated these SNPs as potential genetic markers in goats, with potential applications in breeding programs.

Elevated Free Fatty Acid is Associated with Cardioembolic Stroke Subtype

Background and Objectives:

Free fatty acids (FFAs), an important energy substrate, have an association with cardiovascular diseases, such as atherosclerosis, myocardial dysfunction and abnormal cardiac rhythm. However, limited reports are available on the association between FFAs and ischemic stroke. We hypothesized that plasma FFA concentration could be associated with an ischemic stroke, emphasizing the relationship between FFA and subtypes of ischemic stroke.

Methods:

A cross-sectional study examined the association between FFA concentration and subtypes of stroke and cerebral atherosclerosis from a hospital-based acute stroke registry.

Results:

Data of 715 stroke patients were analyzed. The concentration of FFA was highest in the cardioembolic stroke subtype compared with the other stroke subtypes. Logistic regression analysis revealed that an increase in FFA concentration was significantly associated with the cardioembolic subtype after the adjustment of covariates. FFA concentration was also higher in patients with atrial fibrillation (AF) than those without AF. According to the presence of atherosclerotic stenosis, no significantly difference of FFA concentration was found for intracranial and extracranial cerebral arterial atherosclerosis.

Conclusion:

Here we report a significant association between fasting FFA concentration and the cardioembolic stroke subtype. AF is suggested as the mediating factor between FFA and the cardioembolic stroke subtype.

Associations of common variants in methionine metabolism pathway genes with plasma homocysteine and the risk of type 2 diabetes in Han Chinese

BACKGROUND/AIMS

An association of genetic variants of homocysteine (Hcy) metabolic genes with type 2 diabetes mellitus (T2DM) has been reported. The objective of the present study was to investigate the relationship between the genetic variants in Hcy metabolism-related genes and plasma Hcy levels and T2DM susceptibility in Han Chinese.

METHODS

A total of 774 patients with T2DM and 500 healthy individuals were recruited. Single-nucleotide polymorphism was determined by standard methods.

RESULTS

The Hcy-increasing allele score was positively associated with plasma Hcy levels in both T2DM patients and healthy subjects (r = 0.171 and 0.247, respectively). Subjects with the genotype CC of MTHFR (rs1801131) had a significantly higher likelihood of T2DM compared with subjects with the AA or AA+AC genotypes (OR = 1.93 for CC vs. AA, p = 0.041; OR = 3.13 for CC vs. AA+AC, p = 0.017, respectively). Subjects with the genotype AA of the MTHFD variant (rs2236225) had a significantly lower likelihood of T2DM compared with subjects with the GG or GG+GA genotypes (OR = 0.36 for AA vs. GG, p = 0.027; OR = 0.36 for AA vs. GG+GA, p = 0.017, respectively). In addition, the genotype CT+TT of the PEMT (rs4646356) variants displayed a significant association with an increased risk of T2DM (OR = 1.52 for CT+TT vs. CC, p = 0.042).

CONCLUSIONS

MTHFR rs1801131 C allele and PEMT rs4646356 T allele were associated with a high risk of T2DM in these Han Chinese.

The association of MTHFR C677T gene variants and lipid profiles or body mass index in patients with diabetic and nondiabetic coronary heart disease

BACKGROUND

The aim of this study is to investigate whether methylenetetrahydrofolate reductase (MTHFR) C677T mutation is associated with the development of hyperlipoproteinemia and obesity in coronary heart disease (CHD).

METHODS

This study was carried out in 82 diabetic and 112 nondiabetic patients with CHD and in 138 CHD-free healthy controls. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and agarose gel electrophoresis techniques were used to determine the MTHFR C677T.

RESULTS

Distributions of MTHFR genotypes (C677T dbSNP: rs1801133) were similar in our study groups (P > 0.05). There was no statistical association between biochemical parameters and genotype distribution in nondiabetic CHD patients, while diabetic CC genotype carriers have elevated levels of body mass index (BMI) independently from lipid profiles (P = 0.002). In diabetic CHD patients, while evaluating the clinical parameters according to gender, it was found that gender had an impact on BMI (P = 0.013). Due to this gender effect, a multivariate analysis was conducted on the diabetic CHD patient group. The multivariate logistic regression analysis confirmed that the MTHFR-CC genotype was associated with elevated BMI levels in diabetic CHD patients (odds ratio [OR] = 5.42, P = 0.003).

CONCLUSION

The results of the present study demonstrated that possessing T allele of MTHFR C677T mutation indicates a protective association on BMI independently from other risk factors.

The effect of multiple single nucleotide polymorphisms in the folic acid pathway genes on homocysteine metabolism

Objective. To investigate the joint effects of the single nucleotide polymorphisms (SNPs) of genes in the folic acid pathway on homocysteine (Hcy) metabolism. Methods. Four hundred women with normal pregnancies were enrolled in this study. SNPs were identified by MassARRAY. Serum folic acid and Hcy concentration were measured. Analysis of variance (ANOVA) and support vector machine (SVM) regressions were used to analyze the joint effects of SNPs on the Hcy level. Results. SNPs of MTHFR (rs1801133 and rs3733965) were significantly associated with maternal serum Hcy level. In the different genotypes of MTHFR (rs1801133), SNPs of RFC1 (rs1051266), TCN2 (rs9606756), BHMT (rs3733890), and CBS (rs234713 and rs2851391) were linked with the Hcy level adjusted for folic acid concentration. The integrated SNPs scores were significantly associated with the residual Hcy concentration (RHC) (r = 0.247). The Hcy level was significantly higher in the group with high SNP scores than that in other groups with SNP scores of less than 0.2 (P = 0.000). Moreover, this difference was even more significant in moderate and high levels of folic acid. Conclusion. SNPs of genes in the folic acid pathway possibly affect the Hcy metabolism in the presence of moderate and high levels of folic acid.

Association of homocysteine with type 2 diabetes: a meta-analysis implementing Mendelian randomization approach

BACKGROUND

We tested the hypothesis that elevated homocysteine (Hcy) level is causally associated with increased risk of type 2 diabetes mellitus (T2DM).

RESULTS

The meta-analysis and Mendelian randomization analysis were performed among 4011 cases and 4303 controls. The absolute pooled mean Hcy concentration in subjects with MTHFR 677TT was 5.55 μmol/L (95% CI, 1.33 to 9.77) greater than that in subjects with MTHFR 677CC in T2DM. Overall, the T allele of the MTHFR 677 C > T conferred a greater risk for T2DM [Random effect (RE) OR = 1.31(1.17-1.64), I² = 41.0%, p = 0.055]. The random effect (RE) pooled OR associated with T2DM for MTHFR 677TT relative to the 677CC was [RE OR = 1.38(1.18-1.62)]. The fixed-effect pooled OR of the association for the MTHFR 677 TT vs CT was 1.29 (95% CI, 1.09-1.51). MTHFR 677 TT showed a significantly higher risk for T2DM compared with MTHFR 677 CC + CT [Fixed effect (FE) OR = 1.32(1.14-1.54), I² = 0.0%, p = 0.686]. The absolute pooled mean Hcy concentration in individuals with T2DM was 0.94 μmol/L (95% CI, 0.40-1.48) greater than that in control subjects. The estimated causal OR associated with T2DM was 1.29 for 5 μmol/L increment in Hcy.

CONCLUSIONS

Our findings provided strong evidence on the causal association of Hcy level with the development of T2DM.

Dietary protein and plasma total homocysteine, cysteine concentrations in coronary angiographic subjects

Background

Dietary patterns are associated with plasma total homocysteine (tHcy) concentrations in healthy populations, but the associations between dietary protein and tHcy, total cysteine (tCys) in high risk populations are unclear. We therefore examined the association between dietary protein and tHcy and tCys concentrations in coronary angiographic subjects.

Methods

We conducted a cross-sectional study of 1015 Chinese patients who underwent coronary angiography (40–85 y old). With the use of food-frequency questionnaires, we divided the total protein intakes into high animal-protein and high plant-protein diets. Circulating concentrations of tHcy and tCys were simultaneously measured by high-performance liquid chromatography with fluorescence detection.

Results

We found that high animal-protein diet was positively associated with hyperhomocysteinemia after adjustment for potential confounders, with the subjects in the highest quartile of intake having the greatest increase in risk (OR: 4.14, 95% CI: 2.67-6.43), whereas high plant-protein diet was inversely related to hyperhomocysteinemia, with a higher intake being protective. Compared with the first quartile of intake, the adjusted OR was 0.59 (95% CI: 0.38-0.91) for the fourth quartile. The total protein intake was positively associated with the risk of hypercysteinemia and the participants in highest quartile had significant OR of 1.69 (95% CI: 1.02-2.87) compared with those in lowest quartile. In multivariate linear regression analyses, high animal-protein and total-protein intakes were positively associated with plasma tHcy and tCys concentrations. The plant-protein intake was a negative determinant of plasma tHcy concentrations.

Conclusions

High animal-protein diet was positively associated with high tHcy concentrations, whereas high plant-protein diet was inversely associated with tHcy concentrations. Furthermore the total protein intake was strongly related to tCys concentrations.

The human MTHFR rs4846049 polymorphism increases coronary heart disease risk through modifying miRNA binding

BACKGROUND AND AIMS

Abnormal functioning of 5,10-methylenetetrahydrofolate reductase (MTHFR) enhances the risk for coronary heart disease (CHD). Here, we tested whether a single-nucleotide polymorphism (SNP) located in the 3' untranslated region (UTR) of MTHFR was associated with CHD susceptibility by affecting microRNAs binding.

METHODS AND RESULTS

We first analyzed in silico the SNPs localized in the 3' UTR of MTHFR for their ability to modify miRNA binding. We observed that rs4846049 (G > T) was a potential candidate SNP to modulate miRNAs:MTHFR mRNA complex, with the greatest changed binding free energy for has-miR-149. Based on luciferase analysis, hsa-miR-149 inhibited the activity of the reporter vector carrying -T allele, but not -G allele. We further conducted a case-control study (654 vs 455) in a Chinese Han population. rs4846049 was significantly associated with increased risk for CHD. In addition, the T allele was associated with decreased levels of HDL-cholesterol and apoA. Finally, we observed a reduced MTHFR protein level in peripheral blood mononuclear cells of CHD patients with TT carriers compared to GG carriers of rs4846049.

CONCLUSION

Our results suggest that rs4846049 (G > T) of MTHFR is associated with increased risk for CHD. We also identified a potentially pathogenetic mechanism of SNP-modified posttranscriptional gene regulation by miRNAs to MTHFR.

Effect of polyunsaturated fatty acids on homocysteine metabolism through regulating the gene expressions involved in methionine metabolism

The objective was to investigate the regulatory effect of polyunsaturated fatty acids (PUFAs) on mRNA expression of key genes involved in homocysteine (Hcy) metabolism. Eighty male Sprague Dawley rats were randomly divided into eight groups. The oils were orally administered daily for 8 weeks. Plasma Hcy, phospholipids fatty acids, and mRNA expression were determined. Compared with the control group, plasma Hcy was significantly decreased in the 22:6n-3 and conjugated linoleic acid (CLA) groups; mRNA expression of Mthfr was significantly upregulated in the 22:6n-3, 20:5n-3, and 18:3n-3 groups and downregulated in the 18:2n-6 and stearolic acid (SO) groups. Mat1a was upregulated in the 22:6n-3, 20:5n-3, 18:3n-3, and CLA groups. In addition, Cbs was upregulated in the 22:6n-3, 20:5n-3, 18:3n-3 and CLA groups while downregulated in 18:2n-6 and SO groups. Dietary 22:6n-3 and CLA decrease the plasma concentration of Hcy. mRNA expression of Mthfr, Mat1a, Cbs and Pemt, Gnmt, Mtrr, and Bad is upregulated by n-3 PUFA and downregulated by n-6 PUFA. CLA upregulates mRNA expression of Mat1a and Cbs.

Hyperhomocysteinemia and of Methylenetetrahydrofolate Reductase (C677T) Genetic Polymorphism in Patients with Deep Vein Thrombosis

AIM

To determine the concentration of total plasma homocysteine (tHcy) as well as different genotypes of methylenetetrahydrofolate reductase MTHFR (C677T) in healthy subjects and patients with deep vein thrombosis (DVT).

MATERIAL AND METHODS

The investigation comprised a total of 160 subjects divided in two main groups: 80 healthy subjects (control group) and 80 patients with deep vein thrombosis. Concentration of tHcy was determined by spectrophotometric cyclic enzymatic method and mutation of MTHFR (C677T) gene was examined by polymerase chain reaction according to Schneider.

RESULTS

The results obtained for plasma tHcy in the control group were 11.62±3.43 μmol/L, while tHcy level was significantly higher in patients with deep vein thrombosis as compared to the control group, 15.19±3.63 μmol/L (р<0.001). The analysis of the results has shown that MTHFR (C677T) genetic polymorphism was responsible for mild to moderate hyperhomocysteinemia in the majority of subjects.

CONCLUSION

The level of tHcy in the examined patients was significantly higher in comparison with the control group. Multiple regression analysis has shown that tHcy level in CT and TT genotypes of MTHFR (C677T) was statistically higher in comparison with CC genotype of MTHFR (C677T) in both, the control group and the DVT patients.

Associations of plasma phospholipid fatty acids with plasma homocysteine in Chinese vegetarians

The association of plasma phospholipid (PL) fatty acid composition with plasma homocysteine (Hcy) in Chinese vegetarians is not understood. The main aim of the present study was to investigate the plasma PL fatty acid status, and its association with plasma Hcy in Chinese vegetarians and omnivores. A total of 103 male vegetarians and 128 male omnivores were recruited in Linyin Temple, Hangzhou. Plasma Hcy and PL fatty acid concentrations were determined by standard methods. Compared with omnivores, plasma PL n-3 PUFA (P< 0·001), 22 : 6n-3 (P< 0·001), 22 : 5n-6 (P= 0·021), 22 : 2n-6 (P< 0·001) and SFA (P= 0·017) were significantly lower, while plasma PL n-6 PUFA (P= 0·007) and total PUFA (P< 0·001) were significantly higher in vegetarians. The prevalence of hyperhomocysteinaemia (HHcy) in vegetarians (26·47 %) was significantly higher than that in omnivores (13·28 %). In vegetarians, plasma PL 22 : 6n-3 (r − 0·257, P= 0·046) was significantly negatively associated with plasma Hcy. In omnivores, plasma PL 18 : 1n-7 (r 0·237, P= 0·030) was significantly positively associated with plasma Hcy. Plasma PL 22 : 6n-3 (r − 0·217, P= 0·048) was negatively associated with plasma Hcy in omnivores. Plasma PL SFA were positively associated with the prevalence of HHcy. It would seem appropriate for vegetarians to increase their dietary n-3 PUFA and decrease dietary SFA, and thus reduce the risk of HHcy.

Interactions between dietary n-3 fatty acids and genetic variants and risk of disease

Nutritional genomics has undergone rapid development and the concept is now very popular with the general public. Therefore, there is increasing demand for knowledge on adapting dietary composition to the genome. Our aim has been to undertake a systematic review so as to find out the level of evidence existing on whether the effects of n-3 fatty acids on health can be modulated by genetic variation. A systematic literature search was conducted on studies that jointly analyse the effect of one or more genetic variants in candidate genes and n-3 fatty acids. Both observational and experimental studies were included. Results are classified in accordance with whether the study was undertaken on intermediate phenotypes (plasma lipid concentrations, glucose, inflammation markers, anthropometric measurements) or disease phenotypes (cancer, cardiovascular diseases, metabolic syndrome, etc) and whether it was experimental or observational. A wide diversity of genetic variants and little consistency in the publication of replication studies was found. Greater consistency was observed in studies that involved the FADS1 and FADS2 locus in the determination of n-3 fatty acid concentrations in biological samples. Most of the studies were designed to measure gene-diet interactions and not diet-gene interactions. Despite the fact that multiple studies have shown statistically significant interactions between n-3 fatty acids and certain genetic variants on intermediate and disease phenotypes, the individual level of evidence is very low and recommendations cannot be made on increasing or reducing the intake of n-3 fatty acids based on each individual's genotype.