Genetic polymorphisms involved in folate metabolism and concentrations of methylmalonic acid and folate on plasma homocysteine and risk of coronary artery disease

Methionine synthetase A2756G and Cystathionine-β-synthase 844ins68 polymorphisms and coronary artery disease: A meta-analysis

OBJECTIVE

Methionine synthetase (MS) A2756G and Cystathionine-β-synthase (CBS) 844ins68 gene polymorphisms were indicated to be associated with increased coronary artery disease (CAD) risk. Nevertheless, because the results of each experiment are different, there is no consensus till now. This meta-analysis aimed to clarify the relationship between MS gene A2756G and CBS gene 844ins68 polymorphisms and CAD.

METHODS

11,555 participants from 24 individual studies, 2162 participants from 6 individual studies were included in the MS gene A2756G and CBS 844ins68 gene polymorphisms meta-analysis respectively. To determine whether MS gene A2756G or CBS gene 844ins68 polymorphism was associated with CAD risk, a random or fixed-effect genetic model was adopted using pooled odds ratios (ORs) and their corresponding 95 % confidence intervals (CIs).

RESULTS

MS gene A2756G polymorphism was significantly associated with CAD under recessive (OR: 1.400, 95 % CI: 1.119-1.751, P = 0.003) and homozygous genetic models (OR: 1.360, 95 % CI: 1.084-1.706, P = 0.008). In the African subgroup, the association was significant under the allelic, recessive, dominant, heterozygous, homozygous and additive (P < 0.05) genetic models. In the Asian subgroup, the association was significant under the allelic, recessive and homozygous genetic models (P < 0.05). No significant association was found between CBS 844ins68 gene polymorphism and CAD under all of the genetic models (P > 0.05).

CONCLUSIONS

MS gene A2756G polymorphism was significantly associated with increased CAD risk, especially in the African and Asian population. The G allele carriers of MS gene A2756G polymorphism were more susceptible to be suffered from CAD disease than others.

Association of Methylenetetrahydrofolate Reductase rs1801133 Gene Polymorphism with Cancer Risk and Septin 9 Methylation in Patients with Colorectal Cancer

PURPOSE

Colorectal cancer (CRC) is one of the most common malignancies, with a high incidence and mortality worldwide. Methylated Septin 9 (mSEPT9) has been used clinically as an auxiliary tool for CRC screening. The aim of the present study was to investigate the association of the methylenetetrahydrofolate reductase (MTHFR) rs1801133 polymorphism with the risk of CRC and the methylation status of Septin 9 in CRC.

METHODS

Information of 540 patients with a confirmed diagnosis of CRC and with a physical examination were utilized to assess the association of the MTHFR rs1801133 polymorphism with CRC and the methylation of SEPT9. MTHFR rs1801133 polymorphism was genotyped using polymerase chain reaction (PCR). The commercial Septin 9 Gene Methylation(mSEPT9) Detection Kit was used for plasma SEPT9 methylation analysis.

RESULTS

Among 540 patients, 61.48% were men and the median age was 54.47 ± 13.14. 65.37% of all colorectal tumors developed in the rectum. 195 patients had negative mSEPT9 methylation, while 345 had positive results. 87 individuals with stage I, 90 with stage II, 287 with stage III, and 76 with stage IV colorectal cancer were included in the sample. The results demonstrated that the positivity rate and degree of methylation of mSEPT9 were remarkably higher in patients with more advanced TNM stages than in those with less advanced stages. The frequencies of the MTHFR rs1801133 CC genotype and allele C carriers in patients with CRC were significantly higher than those in healthy individuals (P = 0.006 and P = 0.001, respectively). The positivity rate of the mSEPT9 assay was significantly higher among the MTHFR rs1801133 TT genotype and allele T carriers than among the CC and allele C carriers respectively. The MTHFR rs1801133 TT genotype and allele T carriers were positively associated with the methylation of SEPT9 (OR = 3.320, 95% CI 1.485-7.424, P = 0.003 and OR = 1.783, 95% CI 1.056-3.010, P = 0.030, respectively).

CONCLUSION

In conclusion, individuals harboring the MTHFR rs1801133 CC genotype had a higher risk of CRC and the MTHFR rs1801133 TT carriers were more susceptible to Septin 9 gene methylation.

Association of Thymidylate Synthase (TS) Gene Polymorphisms with Incidence and Prognosis of Coronary Artery Disease

Coronary artery disease (CAD) is a prevalent cardiovascular condition characterized by the accumulation of plaque within coronary arteries. While distinct features of CAD have been reported, the association between genetic factors and CAD in terms of biomarkers was insufficient. This study aimed to investigate the connection between genetic factors and CAD, focusing on the thymidylate synthase (TS) gene, a gene involved in DNA synthesis and one-carbon metabolism. TS plays a critical role in maintaining the deoxythymidine monophosphate (dTMP) pool, which is essential for DNA replication and repair. Therefore, our research targeted single nucleotide polymorphisms that could potentially impact TS gene expression and lead to dysfunction. Our findings strongly associate the TS 1100T>C and 1170A>G genotypes with CAD susceptibility. We observed that TS 1100T>C polymorphisms increased disease susceptibility in several groups, while the TS 1170A>G polymorphism displayed a decreasing trend for disease risk when interacting with clinical factors. Furthermore, our results demonstrate the potential contribution of the TS 1100/1170 haplotypes to disease susceptibility, indicating a synergistic interaction with clinical factors in disease occurrence. Based on these findings, we propose that polymorphisms in the TS gene had the possibility of clinically useful biomarkers for the prevention, prognosis, and management of CAD in the Korean population.

Adequate vitamin B12 and folate status of Norwegian vegans and vegetarians

Plant-based diets may increase the risk of vitamin B12 deficiency due to limited intake of animal-source foods, while dietary folate increases when adhering to plant-based diets. In this cross-sectional study, we evaluated the B12 and folate status of Norwegian vegans and vegetarians using dietary B12 intake, B12 and folic acid supplement use, and biomarkers (serum B12 (B12), plasma total homocysteine (tHcy), plasma methylmalonic acid (MMA) and serum folate). Vegans (n 115) and vegetarians (n 90) completed a 24-h dietary recall and a FFQ and provided a non-fasting blood sample. cB12, a combined indicator for evaluation of B12 status, was calculated. B12 status was adequate in both vegans and vegetarians according to the cB12 indicator; however 4 % had elevated B12. Serum B12, tHcy, MMA concentrations and the cB12 indicator (overall median: 357 pmol/l, 9·0 µmol/l, 0·18 µmol/l, 1·30 (cB12)) did not differ between vegans and vegetarians, unlike for folate (vegans: 25·8 nmol/l, vegetarians: 21·6 nmol/l, P = 0·027). Serum B12 concentration < 221 pmol/l was found in 14 % of all participants. Vegetarians revealed the highest proportion of participants below the recommended daily intake of 2 µg/d including supplements (40 v. 18 %, P < 0·001). Predictors of higher serum B12 concentrations were average daily supplement use and older age. Folate deficiency (< 10 nmol/l) was uncommon overall (< 2·5 %). The combined indicator cB12 suggested that none of the participants was B12-depleted; however, low serum B12 concentration was found in 14 % of the participants. Folate concentrations were adequate, indicating adequate folate intake in Norwegian vegans and vegetarians.

Association between MTHFR C677T variant and risk for congenital heart defects in Egyptian children: a case–control study including meta-analysis based on 147 cases and 143 controls

Background

Stratification analysis studies showed that ethnicity has a significant association regarding MTHFR C677T variant and congenital heart diseases (CHDs) risk, and many published studies have controversial conclusions toward this association.

Methods

In this study, the association between the MTHFR C677T variant and the risk for CHDs was evaluated in 91 children with CHD and 95 healthy controls, as new cases, by using restriction fragment length polymorphism (RFLP) technique. Besides that, 2 case–control studies in the Egyptian population published before 2021 were included in this meta-analysis. The association was assessed by the odds ratio (OR) with a 95% confidence interval (CI) based on 294 alleles in CHD cases and 286 alleles in controls.

Results

The overall meta-analysis showed a significant association between MTHFR C677T variant and CHDs risk in Egyptian children with heterogeneity (Heterogeneity = 0.001) in all the genetic models with the highly significant association in T versus C allele (pooled OR 1.89, 95% CI 1.31–2.74; p value < 0.0004). The consistency of the genotypes was detected by Hardy–Weinberg equilibrium (HWE).

Conclusions

Our results support the MTHFR -677T allele as a susceptibility factor for CHDs in the Egyptian pediatric patients.

Folate-dependent hypermobility syndrome: A proposed mechanism and diagnosis

Hypermobility involves excessive flexibility and systemic manifestations of connective tissue fragility. We propose a folate-dependent hypermobility syndrome model based on clinical observations, and through a review of existing literature, we raise the possibility that hypermobility presentation may be dependent on folate status. In our model, decreased methylenetetrahydrofolate reductase (MTHFR) activity disrupts the regulation of the ECM-specific proteinase matrix metalloproteinase 2 (MMP-2), leading to high levels of MMP-2 and elevated MMP-2-mediated cleavage of the proteoglycan decorin. Cleavage of decorin leads ultimately to extracellular matrix (ECM) disorganization and increased fibrosis. This review aims to describe relationships between folate metabolism and key proteins in the ECM that can further explain the signs and symptoms associated with hypermobility, along with possible treatment with 5-methyltetrahydrofolate supplementation.

Migraine and thyroid dysfunction: Co-occurrence, shared genes and biological mechanisms

BACKGROUND AND PURPOSE

Migraine and thyroid dysfunction, particularly hypothyroidism, are common medical conditions and are known to have high heritability. Thyroid function measures, thyroid stimulating hormone (TSH) and free thyroxine (fT4), are also known to be genetically influenced. Although observational epidemiological studies report an increased co-occurrence of migraine and thyroid dysfunction, a clear and combined interpretation of the findings is currently lacking. A narrative review is provided of the epidemiological and genetic association evidence linking migraine, hypothyroidism, hyperthyroidism and thyroid hormones TSH and fT4.

METHODS

An extensive literature search was conducted in the PubMed database for epidemiological, candidate gene and genome-wide association studies using the terms migraine, headache, thyroid hormones, TSH, fT4, thyroid function, hypothyroidism and hyperthyroidism.

RESULTS

Epidemiological studies suggest a bidirectional relationship between migraine and thyroid dysfunction. However, the nature of the relationship remains unclear, with some studies suggesting migraine increases the risk for thyroid dysfunction whilst other studies suggest the reverse. Early candidate gene studies have provided nominal evidence for MTHFR and APOE, whilst more recently genome-wide association studies have provided robust evidence for THADA and ITPK1 being associated with both migraine and thyroid dysfunction.

CONCLUSIONS

These genetic associations improve our understanding of the genetic relationship between migraine and thyroid dysfunction, provide an opportunity to develop biomarkers to identify migraine patients most likely to benefit from thyroid hormone therapy, and indicate that further cross-trait genetic studies have excellent potential to provide biological insight into their relationship and inform clinical interventions.

The Regulation and Characterization of Mitochondrial-Derived Methylmalonic Acid in Mitochondrial Dysfunction and Oxidative Stress: From Basic Research to Clinical Practice

Methylmalonic acid (MMA) can act as a diagnosis of hereditary methylmalonic acidemia and assess the status of vitamin B12. Moreover, as a new potential biomarker, it has been widely reported to be associated with the progression and prognosis of chronic diseases such as cardiovascular events, renal insufficiency, cognitive impairment, and cancer. MMA accumulation may cause oxidative stress and impair mitochondrial function, disrupt cellular energy metabolism, and trigger cell death. This review primarily focuses on the mechanisms and epidemiology or progression in the clinical study on MMA.

Association of methylenetetrahydrofolate reductase gene polymorphisms and maternal folic acid use with the risk of congenital heart disease

BACKGROUND

To systematically evaluate the association of MTHFR genetic polymorphisms, maternal folic acid intake, and the time when folic acid intake was started with the risk of congenital heart disease (CHD) and investigated the role of their interaction on infant CHD risk in Chinese populations.

METHODS

A case-control study involving 592 CHD cases, 617 health controls, and their mothers was performed. The exposures of interest were single nucleotide polymorphisms (SNPs) of the MTHFR gene, maternal folic acid use, and the time when folic acid use was started. We applied the logistic regression model to explore the strength of association.

RESULTS

Our findings showed that mothers lacking folic acid intake had a significantly higher risk of CHD in offspring (aOR = 2.00; 95%CI: 1.34-2.98). Mothers who started to use folic acid from the first trimester of the fetation (aOR = 1.65; 95% CI: 1.22-2.23) or from the second trimester of the fetation (aOR = 7.77; 95% CI: 2.52-23.96), compared with those starting to use folic acid from 3 months previous to the conception, were at a significantly higher risk of CHD in offspring. Genetic variants at rs2066470 (AA vs. GG: aOR = 5.09, 95%CI: 1.99-13.03), rs1801133 (AA vs. GG: aOR = 2.49, 95%CI: 1.58-3.93), and rs1801131 (TG vs. TT: aOR = 1.84, 95%CI: 1.36-2.50; GG vs. TT: aOR = 3.58, 95%CI: 1.68-7.63) were significantly associated with the risk of CHD based on the multivariate analysis. Additionally, statistically significant interactions between maternal folic acid intake and genetic variants of the MTHFR gene at rs1801133 and rs1801131 were observed.

CONCLUSION

An association of maternal folic acid intake and the time when intake was started with the risk of CHD in offspring was found. What's more, maternal folic acid fortification may help counteract partial of the risks of CHD in offspring attributable to MTHFR genetic mutations.

REGISTRATION NUMBER

http://www.chictr.org.cn/edit.aspx?pid=28300&htm=4, identifier: ChiCTR1800016635.

Environmental and Genetic Risk Factors of Congenital Anomalies: an Umbrella Review of Systematic Reviews and Meta-Analyses

BACKGROUND

The prevalence of congenital anomalies in newborns in South Korea was 272.9 per 100,000 in 2005, and 314.7 per 100,000 in 2006. In other studies, the prevalence of congenital anomalies in South Korea was equivalent to 286.9 per 10,000 livebirths in 2006, while it was estimated 446.3 per 10,000 births during the period from 2008 to 2014. Several systematic reviews and meta-analyses analyzing the factors contributing to congenital anomalies have been reported, but comprehensive umbrella reviews are lacking.

METHODS

We searched PubMed, Google Scholar, Cochrane, and EMBASE databases up to July 1, 2019, for systematic reviews and meta-analyses that investigated the effects of environmental and genetic factors on any type of congenital anomalies. We categorized 8 subgroups of congenital anomalies classified according to the 10th revision of the International Statistical Classification of Diseases (ICD-10). Two researchers independently searched the literature, retrieved the data, and evaluated the quality of each study.

RESULTS

We reviewed 66 systematic reviews and meta-analyses that investigated the association between non-genetic or genetic risk factors and congenital anomalies. Overall, 269 associations and 128 associations were considered for environmental and genetic risk factors, respectively. Congenital anomalies based on congenital heart diseases, cleft lip and palate, and others were associated with environmental risk factors based on maternal exposure to environmental exposures (air pollution, toxic chemicals), parental smoking, maternal history (infectious diseases during pregnancy, pregestational and gestational diabetes mellitus, and gestational diabetes mellitus), maternal obesity, maternal drug intake, pregnancy through artificial reproductive technologies, and socioeconomic factors. The association of maternal alcohol or coffee consumption with congenital anomalies was not significant, and maternal folic acid supplementation had a preventive effect on congenital heart defects. Genes or genetic loci associated with congenital anomalies included MTHFR, MTRR and MTR, GATA4, NKX2-5, SRD5A2, CFTR, and 1p22 and 20q12 anomalies.

CONCLUSION

This study provides a wide perspective on the distribution of environmental and genetic risk factors of congenital anomalies, thus suggesting future studies and providing health policy implications.

Methylenetetrahydrofolate Reductase (MTHFR) C677T and A1298C Polymorphisms in Georgian Females with Hypothyroidism

The aim of this study was to investigate the frequency of methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms in Georgian females with hypothyroidism. Thirty-four patients and 29 healthy individuals were recruited in this study. Polymerase chain reaction-restriction fragment length polymorphism analyses were used for genotyping of MTHFR polymorphisms. The results of this study suggest that the MTHFR C677T variant was significantly associated with hypothyroidism. In addition, in individuals with T allele risk of hypothyroidism significantly increased. Combination of CT/AA genotypes was more prevalent in the hypothyroid patients than in the control group. Thus, C677T polymorphism could be a possible genetic factor contributing to the pathophysiology of hypothyroidism, possibly through hyperhomocysteinemia.

MTHFR Gene Polymorphisms Prevalence and Cardiovascular Risk Factors Involved in Cardioembolic Stroke Type and Severity

Background: Cardioembolic stroke (CES), generally known as the most severe subtype of ischemic stroke, is related to many factors, including diabetes mellitus (DM), hypertension (HTN), smoking, hyperlipidemia and atrial fibrillation (AF). Genetic mutations of the methylenetetrahydrofolate reductase (MTHFR) gene C677T and A1298C have been recently associated with ischemic stroke. The purpose of this study was to analyze the prevalence of MTHFR gene polymorphisms correlated with cardiovascular risk factors in a selected population of patients with CES due to non-valvular AF (NVAF). Methods: This cross-sectional study was performed on 67 consecutive patients with acute cardioembolic stroke admitted to our hospital. The protocol included general physical examination, neurological clinical status and stroke severity evaluation, imagistic evaluation and genetic testing of MTHFRC677T and A1298C polymorphisms. Results: The prevalence of MTHFR polymorphisms in the study population was 38.2% for C677T and 40.3% for A1298C. The C677T mutation was significantly correlated with increased diastolic blood pressure (DBP) values (p = 0.007), higher total cholesterol (TC) (p = 0.003), low-density lipoprotein cholesterol (LDLc) (p = 0.003) and triglycerides (TGL) (p = 0.001), increased high-sensitive C-reactive protein (hsCRP) values (p = 0.015), HbA1c (p = 0.004) and left ventricle ejection fraction (LVEF) (p = 0.047) and lower high-density lipoprotein cholesterol (HDLc) (p < 0.001) compared to patients without this genetic variant. This genetic profile also included significantly higher CHA₂DS₂VASC (p = 0.029) and HASBLED (Hypertension, Abnormal liver/renal function, Stroke, Bleeding, Labile INR, Elderly age(>65 years), Drug/Alcohol usage history/Medication usage with bleeding predisposition) (p = 0.025) scores. Stroke severity in patients with MTHFRA1298C mutation was significantly increased when applying National Institutes of Health Stroke Scale (NIHSS) (p = 0.006) and modified Rankin scale (mRS) (p = 0.020) scores. The presence of A1298C mutation as a dependent variable was associated with significantly higher TGL values (odds ratio (OR) = 2.983, 95%CI = (1.972, 7.994)). Conclusions: The results obtained in this study demonstrate that MTHFR gene polymorphisms have a high prevalence in an NVAF cardioembolic stroke population. Moreover, an association between C677T mutation and stroke severity was highlighted. The C677T mutation in patients with NVAF was correlated with a higher incidence of cardiovascular comorbidities (hypertension HTN, heart failure (HF), dyslipidemia, type II diabetes mellitus (T2DM) with high HbA1c and increased inflammatory state). The A1298CMTHFR gene mutation was associated with a higher incidence of previous lacunar stroke and stroke recurrence rate, while dyslipidemia was the main cardiovascular comorbidity in this category.

Association Between MTHFR C677T Polymorphism and Congenital Heart Disease

Many published studies have evaluated the association between the 5,10-methylenetetrahydrofolate reductase (MTHFR) C677T (rs1801133) polymorphism and the risk of congenital heart disease (CHD); however, the specific conclusion is still controversial.To get a more accurate conclusion, we used a meta-analysis to evaluate the association between the MTHFR gene C677T polymorphism and the risk of CHD.Based on the design-based search strategy, a comprehensive literature search was conducted on PubMed, OVID, Cochrane Library, Embase, Wanfang, CNKI, and Web of Science. We selected the Newcastle-Ottawa Scale (NOS) to assess the quality of the included studies. We performed a heterogeneity test on the results of the study and calculated the combined odds ratios (ORs) and its corresponding 95% confidence intervals (95% CIs) under a random- or fixed-effect model. Subgroup analyses were conducted by ethnicity, source of controls, sample size, and genotyping method. Sensitivity analysis was used to insure authenticity of this meta-analysis result. Egger's test and Begg's funnel plot were performed to detect publication bias.Eventually, our meta-analysis included 15 eligible studies. We observed a significant correlation between the MTHFR C677T polymorphism and the development of CHD in the recessive model (OR: 1.35, 95% CI: 1.06-1.71, P = 0.006) for the overall population. In subgroups stratified by ethnicity and source of controls, subgroup analyses indicated similar associations in Asians and hospital-based groups, but not for Caucasians and population-based groups. Egger's test and Begg's funnel plot demonstrated no significant publication bias in our study.Our analysis identified that MTHFR C677T allele is a risk genetic for CHD development, especially in Asians compared with Caucasians.

The MTHFR promoter hypermethylation pattern associated with the A1298C polymorphism influences lipid parameters and glycemic control in diabetic patients

BACKGROUND

Polymorphisms in the gene encoding methylenetetrahydrofolate reductase (MTHFR) have been investigated as risk factors for microvascular complications of diabetes; however, simultaneous analysis of these polymorphisms and the methylation pattern of the gene has never been conducted. The objective of the present study was to evaluate the simultaneous relationship between MTHFR methylation and MTHFR C6TT7 and A1298C polymorphisms with metabolic, inflammatory and oxidative stress parameters related to microvascular complications, diabetic retinopathy (DR) and diabetic nephropathy (DN) in diabetic patients.

METHODS

A total of 107 patients who were diagnosed in the previous 5 to 10 years were recruited and divided into groups with complications (DR and/or DN) or without complications. Methylation analysis of the gene promoter was conducted using the MSP technique, and analysis of the A1298C and C677T polymorphisms was conducted using the restriction fragment length polymorphism (RFLP) assay. Microalbuminuria was determined using urine samples, and other analytes of interest were determined in blood samples using commercial kits. The Mann-Whitney and Chi square statistical tests were used with significance considered at p < 0.05.

RESULTS

Subjects with a hypermethylated profile and the 1298AA genotype showed the highest levels of blood glucose (p = 0.03), total cholesterol (p = 0.0001) and LDL cholesterol (p = 0.0006). The same profile was associated with higher levels of HbA1c (p = 0.025), glycemia (p = 0.04) and total cholesterol (0.004) in the control group and total cholesterol (p = 0.005) and LDL cholesterol (p = 0.002) in the complications group. Serum creatinine was higher in subjects in the hypermethylated group with the genotype 677CC only in the control group (p = 0.0020). The methylated profile in presence of 677CC + 1298AA and the 677CT/TT +1298AA haplotypes showed higher levels of total cholesterol (p = 0.0024; 0.0031) and LDL cholesterol (p = 0.0060; 0.0125) than 1298AC/CC carriers. The fasting glycemia was higher in hypermethylated profile in the presence of 677CC/1298AA haplotype (p = 0.0077).

CONCLUSION

The hypermethylated methylation profile associated with the 1298AA genotype appeared to be connected to higher values of glycemia, total cholesterol and LDL cholesterol.

Choline metabolites: gene by diet interactions

PURPOSE OF REVIEW

The review highlights recent advances in our understanding of the interactions between genetic polymorphisms in genes that metabolize choline and the dietary requirements of choline and how these interactions relate to human health and disease.

RECENT FINDINGS

The importance of choline as an essential nutrient has been well established, but our appreciation of the interaction between our underlying genetic architecture and dietary choline requirements is only beginning. It has been shown in both human and animal studies that choline deficiencies contribute to diseases such as nonalcoholic fatty liver disease and various neurodegenerative diseases. An adequate supply of dietary choline is important for optimum development, highlighted by the increased maternal requirements during fetal development and in breast-fed infants. We discuss recent studies investigating variants in PEMT and MTHFR1 that are associated with a variety of birth defects. In addition to genetic interactions, we discuss several recent studies that uncover changes in fetal global methylation patterns in response to maternal dietary choline intake that result in changes in gene expression in the offspring. In contrast to the developmental role of adequate choline, there is now an appreciation of the role choline has in cardiovascular disease through the gut microbiota-mediated metabolite trimethylamine N-oxide. This pathway highlights some of our understanding of how the microbiome affects nutrient processing and bioavailability. Finally, to better characterize the genetic architecture regulating choline requirements, we discuss recent results focused on identifying polymorphisms that regulate choline and its derivative products.

SUMMARY

Here we discuss recent studies that have advanced our understanding of how specific alleles in key choline metabolism genes are related to dietary choline requirements and human disease.

Homocysteine Metabolism Gene Polymorphisms (MTHFR C677T, MTHFR A1298C, MTR A2756G and MTRR A66G) Jointly Elevate the Risk of Folate Deficiency

Folate deficiency is strongly associated with cardiovascular disease. We aimed to explore the joint effect of the methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C, methionine synthase (MTR) A2756G, and methionine synthase reductase (MTRR) A66G polymorphisms on folate deficiency in a Chinese hypertensive population. A total of 480 subjects aged 28–75 were enrolled in this study from September 2005–December 2005 from six hospitals in different Chinese regions. Known genotypes were detected by PCR-RFLP methods and serum folate was measured by chemiluminescence immunoassay. Our results showed that MTHFR 677TT and MTR 2756AG + GG were independently associated with a higher risk of folate deficiency (TT vs. CC + CT, p < 0.001 and AG + GG vs. AA p = 0.030, respectively). However, the MTHFR A1298C mutation may confer protection by elevating the serum folate level (p = 0.025). Furthermore, patients carrying two or more risk genotypes showed higher odds of folate deficiency than null risk genotype carriers, especially those carrying four risk genotypes. These findings were verified by generalized multifactor dimensionality reduction (p = 0.0107) and a cumulative effects model (p = 0.001). The results of this study have shown that interactions among homocysteine metabolism gene polymorphisms lead to dramatic elevations in the folate deficiency risk.

Association between MTHFR polymorphisms and congenital heart disease: a meta-analysis based on 9,329 cases and 15,076 controls

The aim of our study was to evaluate the association between polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene and the risk for congenital heart disease (CHD). Electronic literature databases were searched to identify eligible studies published before Jun, 2014. The association was assessed by the odds ratio (OR) with a 95% confidence interval (CI). The publication bias was explored using Begg's test. Sensitivity analysis was performed to evaluate the stability of the crude results. A total of 35 studies were included in this meta-analysis. For the MTHFR C677T polymorphism, we detected significant association in all genetic models for Asian children and the maternal population. Significant association was also detected in T vs. C for a Caucasian paediatric population (OR = 1.163, 95% CI: 1.008–1.342) and in both T vs. C (OR = 1.125, 95% CI: 1.043–1.214) and the dominant model (OR = 1.216, 95% CI:b1.096–1.348) for a Caucasian maternal population. For the MTHFR A1298C polymorphism, the association was detected in CC vs. AC for the Caucasian paediatric population (OR = 1.484, 95% CI: 1.035–2.128). Our results support the MTHFR -677T allele as a susceptibility factor for CHD in the Asian maternal population and the -1298C allele as a risk factor in the Caucasian paediatric population.

Change of hs-CRP, sVCAM-1, NT-proBNP levels in patients with pregnancy-induced hypertension after therapy with magnesium sulfate and nifedipine

OBJECTIVE

To investigate the change of the hs-CRP, sVCAM-1, NT-proBNP levels of the patients with pregnancy-induced hypertension (PIH) syndrome.

METHODS

A total of 200 patients with PIH were divided into mild, moderate and severe group, and 50 healthy pregnancy patients served as the control group. The serum sVCAM-1 levels were detected by enzyme-linked immunosorbent assay, hs-CRP were detected by immunity transmission turbidity, and NT-proBNP levels were determined by the colloidal gold method. Patients were treated with magnesium sulfate and nifedipine and the contrastive analysis was performed before and after treatment. And the pathological changes in placental of PIH patients were detected by hematoxylin-eosin staining at the same time.

RESULTS

The hs-CRP, sVCAM-1, NT-proBNP levels of patients in the mild, moderate and severe PIH group were significantly higher than that in the control group (P<0.05). The hs-CRP, sVCAM-1, NT-proBNP levels in the severe group were significantly higher than the mild group and the moderate group, the difference was statistically significant (P<0.05). The hs-CRP, sVCAM-1, NT-proBNP of the moderate group were significantly higher than the mild group (P<0.05). There was a positive correlation between hs-CRP, sVCAM-1, NT-proBNP expression levels and the degree of the PIH. The expression of hs-CRP, sVCAM-1, NT-proBNP levels of the moderate and the severe group were significantly decreased (P<0.05). The number of placental villi and interstitial blood vessel in the moderate and severe PIH group were significantly less than the control group (P<0.05).

CONCLUSIONS

The increased levels of serum hs-CRP, sVCAM-1, NT-proBNP may be involved in the process of vascular endothelial cell injury of the PIH, and the hs-CRP, sVCAM-1, NT-proBNP can be used as the auxiliary index for diagnosis of PIH and determination of PIH severity.

Are plasma homocysteine concentrations in Brazilian adolescents influenced by the intake of the main food sources of natural folate?

BACKGROUND

Folate, a B vitamin, has been associated with a reduced concentration of plasma homocysteine (phcy), a marker of cardiovascular disease. The contribution of fruits and vegetables (FV) and other natural folate-rich foods to folate intake and folate status in Brazilian adolescents has hardly been determined.

OBJECTIVES

To investigate the intake of FV and beans and its association with the concentration of phcy in adolescents.

METHODS

This was a cross-sectional population-based study with a complex sample survey, with 198 adolescents who completed two 24-hour dietary recalls, a food frequency questionnaire, and a fasting blood draw. Usual dietary intake estimates were derived applying the Multiple Source Method. Three different generalized linear models with a gamma distribution were developed for each sex to evaluate the relationship between phcy and tertiles of FV intake as well as to evaluate the relationship between phcy and tertiles of FV and bean intake.

RESULTS

No association was found between phcy concentration and FV intake or between phcy and FV and beans. Serum folate and female sex were inversely related to phcy.

CONCLUSION

Phcy was not related to FV or FV and beans; this may be attributable to a low intake of these food groups.

Genetic interactions between MTHFR (C677T), methionine synthase (A2756G, C2758G) variants with vitamin B12 and folic acid determine susceptibility to premature coronary artery disease in Indian population

Background:

Researchers have determined that Indians face a higher risk of heart disease, despite the fact that nearly half of them are vegetarians and lack many of the other traditional risk factors. In the below-30 age group, coronary artery disease mortality among Indians is three-fold higher than in the whites in United Kingdom and ten-fold higher than the Chinese in Singapore. High levels of homocysteine have been widely linked to the early onset of heart diseases in other populations, although a definite proof among Indians is lacking, which needs to be investigated by way of screening for factors responsible for high homocysteine levels.

Objective:

To screen for genetic factors responsible for hyperhomocysteinemia and the risk for premature coronary artery disease.

Materials and Methods:

A total of 100 individuals with proven premature coronary artery disease and 200 age-and-sex matched controls were screened for polymorphisms in Methylenetetrahydrofolate reductase (MTHFR) (C677T) Methionine synthase (MS) genes (A2756G, C2758G), and the B12 and Folate levels were estimated.

Results:

Results from the mutational analysis revealed that in the study group, seven individuals had a polymorphism for the C677T allele in the MTHFR gene (one homozygous and six heterozygous) (Fischer's Exact test P > 0.046) (OR: 0.2711 95% CI 0.0774 to 0.9491). Six were heterozygous for the A2756G polymorphism in the MS gene (Fischer's Exact test P > 0.0012). None showed a polymorphism at the C2758G allele in the MS gene. Four controls showed heterozygosity for the C677T polymorphism and none for the MS gene. The B12 and Folate levels were significantly lower in the study group as compared to the controls.

Conclusions:

It is important to know which factors determine the total homocysteine concentrations. In the general population, the most important modifiable determinants of tHcy are folate intake and coffee consumption. Smoking and alcohol consumption are also associated with the total homocysteine concentrations, but more research is necessary to elucidate whether these relations are not originating from residual confounding due to other lifestyle factors.

Three genetic polymorphisms of homocysteine-metabolizing enzymes and risk of coronary heart disease: a meta-analysis based on 23 case-control studies

Many epidemiological studies have explored the relationships between three genetic polymorphisms of genes encoding homocysteine-metabolizing enzymes (methionine synthase [MTR] A2756G, methionine synthase reductase [MTRR] A66G, and N(5),N(10)-methylenetetrahydrofolate reductase [MTHFR] A1298C) and risk of coronary heart disease (CHD), but no conclusive results were obtained. Therefore, we performed a meta-analysis of 23 case-control studies. Odds ratio (OR) and 95% confidence interval (95% CI) were used to examine the strength of the associations. Among those primary studies, 22 studies were for Europeans, and one study focused on the MTR A2756G polymorphism in Asians. The results of combined analyses of the MTR A2756G polymorphism suggested that the G allele was associated with increased risk of CHD and myocardial infarction (MI) especially for Europeans (GG vs. AA for CHD: OR [95% CI]=1.63 [1.18-2.25], p(z)(-test)=0.001, p(heterogeneity)=0.274; GG+AG vs. AA for MI: OR [95% CI]=1.44 [1.08-1.93], p(z)(-test)=0.014, p(heterogeneity)=0.611). In addition, the G allele was also associated with higher risk CHD based on population-based case-control studies (PCC) (GG vs. AA: OR [95% CI]=1.75 [1.24-2.49], p(z)(-test)=0.002, p(heterogeneity)=0.316). The results suggested that the MTRR A66G polymorphism was not associated with risk of CHD for Europeans (AA vs. GG: OR [95% CI]=1.07 [0.59-1.94], p(z)(-test)=0.831, p(heterogeneity)<0.01). The results suggested that the C allele of the MTHFR A1298C polymorphism might be associated with the increased risk of MI for Europeans (CC vs. CA+AA: OR [95% CI]=1.37 [1.03-1.84], p(z)(-test)=0.033, p(heterogeneity)=0.668). However, when subgroup analyses for sources of controls were performed, conflicting results were obtained. The results suggested that the C allele was associated with decreased risk of CHD based on hospital-based case-control studies, but associated with increased risk of CHD based on PCC. This meta-analysis suggests that MTR A2756G polymorphism, but not MTRR A66G and MTHFR A1298C, is associated with risk of CHD for Europeans. Because of limitations and potential bias, more well-designed studies with larger sample size, especially focused on Asians and Africans, should be performed in the future.