Associations of MTHFR and MTRR polymorphisms with serum lipid levels in Chinese hypertensive patients

Docosahexaenoic acid, eicosapentaenoic acid, arachidonic acid, and neural tube defects in Tunisian population

OBJECTIVE

To determine the effect of maternal status in (plasma and red blood cell) folate, vitamin B12, homocysteine, and vitamin D, as well as their interaction with MTHFR (C677T and A1298C) and MTRR A66G polymorphisms, on maternal plasma docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and arachidonic acid (ARA) levels and the risk of neural tube defects (NTDs).

METHODS

ARA, EPA, and DHA composition was assessed using capillary gas chromatography.

RESULTS

ARA and DHA levels were higher in controls than in case mothers for low plasma folate status. For low red blood cell folate status, DHA levels were higher in controls than in case mothers. For high homocysteine levels, ARA and DHA levels were higher in controls than in case mothers. NTD mothers had lower EPA and DHA levels for low vitamin B12 levels. NTD mothers had lower DHA levels for low vitamin D levels. For low plasma folate status, DHA levels in the MTHFR C677T gene and ARA and EPA levels in MTHFR A1298C gene were different among the three genotypes in case mothers. DHA levels in the MTHFR C677T gene were different among the three genotypes in case mothers for both low and high homocysteine levels. For low vitamin B12 levels, ARA and DHA levels were different among the three genotypes of the MTHFR C677T gene in case mothers. In the MTHFR C677T gene, ARA and DHA levels were different among the three genotypes in case mothers for low vitamin D levels.

CONCLUSIONS

More advanced research is required to verify a suitable biochemical parameter status in relation to the genotypes in pregnant women.

Association of MTHFR (C677T, A1298C) and MTRR A66G polymorphisms with fatty acids profile and risk of neural tube defects

OBJECTIVE

This study aims to determine if 5,10-methylenetetrahydrofolate reductase (MTHFR C677T and A1298C) and methionine synthase reductase (MTRR A66G) gene polymorphisms were associated with fatty acid (FA) levels in mothers of fetuses with neural tube defects (NTDs) and whether these associations were modified by environmental factors.

METHODS

Plasma FA composition was assessed using capillary gas chromatography. Concentrations of studied FA were compared between 42 mothers of NTDs fetuses and 30 controls as a function of each polymorphism by the Kruskal-Wallis nonparametric test.

RESULTS

In MTHFR gene C677T polymorphism, cases with (CT + TT) genotype had lower monounsaturated FAs (MUFA) and omega-3 polyunsaturated FA (n-3 PUFA) levels, but higher omega-6 polyunsaturated FAs (n-6 PUFA) and omega-6 polyunsaturated FAs: omega-3 polyunsaturated FAs (n-6:n-3) ratio levels. In MTRR gene A66G polymorphism, cases with (AG + GG) genotype had lower MUFA levels, but higher PUFA and n-6 PUFA levels. Controls with (AG + GG) genotype had lower n-6 PUFA levels. In MTHFR gene C677T polymorphism, cases with smoking spouses and (CT + TT) genotype had lower MUFA and n-3 PUFA levels, but higher PUFA, n-6 PUFA, and n-6:n-3 ratio levels. Cases with (CT + TT) genotype and who used sauna during pregnancy had lower n-3 PUFA levels. In MTRR gene A66G polymorphism, cases with (AG + GG) genotype and who used sauna during pregnancy had higher PUFA and n-6 PUFA levels.

CONCLUSIONS

Further research is required to clarify the association of FA metabolism and (MTHFR, MTRR) polymorphisms with NTDs.

Association analysis of MTHFR (rs1801133 and rs1801131) and MTRR (rs1801394) gene polymorphisms towards the development of hypertension in the Bai population from Yunnan, China

OBJECTIVE

Hypertension is one of the leading causes of human death and disability. MTHFR and MTRR regulate folate metabolism and are closely linked to hypertension, although the relationship is inconsistent among different ethnic groups. The present study aims to investigate the effects of MTHFR C677T (rs1801133), MTHFR A1298C (rs1801131), and MTRR A66G (rs1801394) polymorphisms on hypertension susceptibility in the Bai nationality of the Yunnan Province, China.

METHODS

This case-control study included 373 hypertensive patients and 240 healthy controls from the Chinese Bai population. The genotyping of MTHFR and MTRR gene polymorphisms was carried out by using the KASP method. The effects of genetic variations of MTHFR and MTRR genes on hypertension risk were evaluated with odds ratios (OR) and 95% confidence intervals (95% CI).

RESULTS

The present study revealed that the CT and TT genotypes and T allele of MTHFR C677T locus were considerably associated with an increased risk of hypertension. In addition, MTHFR A1298C locus CC genotype could significantly increase the hypertension risk. The T-A and C-C haplotypes of MTHFR C677T and MTHFR A1298C could increase the risk of hypertension. Further stratified analysis by risk rank of folate metabolism indicated that people with poor utilization of folic acid were more prone to develop hypertension. In the hypertension group, the MTHFR C677T polymorphism was significantly associated with fasting blood glucose, fructosamine, apolipoprotein A1, homocysteine, superoxide dismutase, and malondialdehyde levels.

CONCLUSION

Our study suggested that genetic variations of MTHFR C677T and MTHFR A1298C were significantly associated with susceptibility to hypertension in the Bai population from Yunnan, China.

Methylenetetrahydrofolate reductase deficiency and high-dose FA supplementation disrupt embryonic development of energy balance and metabolic homeostasis in zebrafish

Folic acid (synthetic folate, FA) is consumed in excess in North America and may interact with common pathogenic variants in methylenetetrahydrofolate reductase (MTHFR); the most prevalent inborn error of folate metabolism with wide-ranging obesity-related comorbidities. While preclinical murine models have been valuable to inform on diet-gene interactions, a recent Folate Expert panel has encouraged validation of new animal models. In this study, we characterized a novel zebrafish model of mthfr deficiency and evaluated the effects of genetic loss of mthfr function and FA supplementation during embryonic development on energy homeostasis and metabolism. mthfr-deficient zebrafish were generated using CRISPR mutagenesis and supplemented with no FA (control, 0FA) or 100 μm FA (100FA) throughout embryonic development (0-5 days postfertilization). We show that the genetic loss of mthfr function in zebrafish recapitulates key biochemical hallmarks reported in MTHFR deficiency in humans and leads to greater lipid accumulation and aberrant cholesterol metabolism as reported in the Mthfr murine model. In mthfr-deficient zebrafish, energy homeostasis was also impaired as indicated by altered food intake, reduced metabolic rate and lower expression of central energy-regulatory genes. Microglia abundance, involved in healthy neuronal development, was also reduced. FA supplementation to control zebrafish mimicked many of the adverse effects of mthfr deficiency, some of which were also exacerbated in mthfr-deficient zebrafish. Together, these findings support the translatability of the mthfr-deficient zebrafish as a preclinical model in folate research.

Associations of MTHFR gene polymorphism with lipid metabolism and risk of cerebral infarction in the Northwest Han Chinese population

Objective

Genetic variation in the methylenetetrahydrofolate reductase (MTHFR) gene may contribute to the development of cerebral infarction (CI); however, results have been inconsistent across studies with different populations, including studies of the Chinese population. The aim of this study was to analyze the effect of MTHFR gene polymorphism on serum lipid and homocysteine levels among patients with CI in the Northwest Chinese Han population.

Patients and methods

A total of 521 CI patients and 524 non-CI controls were enrolled in the study. Polymerase chain reaction and hybridization were utilized to identify MTHFR gene polymorphisms. Multivariate logistic regression analysis was used to assess the associations of MTHFR gene polymorphism with risk of CI.

Results

Frequencies of the TT genotype and the T allele were markedly higher among CI patients than among controls. After stratifying our data by sex and age, we determined that these differences in frequency of the TT genotype and the T allele were statistically significant among participants of two different age brackets and among men, but not among women (i.e., there were no statistically significant differences between female patients and female controls). CI patients and control participants with the CT or TT genotype had significantly higher homocysteine (Hcy) levels than those with the CC genotype. Among CI patients, CT/TT carriers showed significantly lower high-density lipoprotein cholesterol (HDL-C) and apolipoprotein A-I (ApoA-I) levels as compared with CC carriers, but there was no significant difference for control participants. Multivariable logistic regression analysis showed that drinking; smoking; diabetes mellitus; levels of Hcy, direct bilirubin (DB), indirect bilirubin (IB), ApoA-I, and total protein (TP); and TT genotype were significant independent risk factors for CI.

Conclusions

The results suggested that the TT genotype of the MTHFR C677T gene polymorphism, which is associated with hyperhomocysteinemia (HHcy), might be of great clinical significance in the identification of new biomarkers for CI and in the development of individualized preventive and therapeutic strategies.

Associations of Two Common Polymorphisms in MTHFR Gene with Blood Lipids and Therapeutic Efficacy of Simvastatin

BACKGROUND AND PURPOSE

Cardio-cerebrovascular disease is an important public health challenge worldwide, and its complex etiology has not been elucidated fully. The study was to investigate the relationship between two common polymorphisms C677T and A1298C in the methylenetetrahydrofolate reductase (MTHFR) gene, baseline lipids and the lipid-lowering efficacy of simvastatin in a Chinese hyperlipidemic population.

METHODS

All participants were recruited from Anhui, China. By the extreme sampling method, we selected subjects with low response (n=108) and high response (n=106) based on their adjusted lipid-lowering response to simvastatin administrated for 8 consecutive weeks. Both MTHFR C677T and A1298C loci were genotyped by MALDI-TOF MS platform. Serum triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) levels were measured at baseline and after 8 weeks of oral 20 mg/d tablet of simvastatin.

RESULTS

Patients with the 677TT genotype had significantly higher baseline TC, HDL-C, and change in HDL-C (ΔHDL-C) levels after treatment than those with 677CC+CT genotypes (β = 0.207, P = 0.045; β = 0.182, P = 0.026; and β = 0.16, P = 0.002, respectively). Patients with 1298AC+CC genotypes had significantly higher baseline LDL-C and change in LDL-C (ΔLDL-C) levels (β = 0.276, P =0.043; β = 0.359, P = 0.025, respectively) than those with 1298AA genotype. We found statistical interactions between the two SNPs in association with baseline HDL-C (P for interaction = 0.034), TC (P for interaction = 0.069), and TG (P for interaction = 0.034). Baseline TC (P = 0.027) and HDL-C (P = 0.046) and change in HDL-C (P = 0.019) were different among those with the MTHFR A-T haplotype compared with A-C.

CONCLUSIONS

Our major findings suggest that both MTHFR C677T and A1298C polymorphisms could be important genetic determinants of lipid traits and drug efficacy of simvastatin. This will contribute to a better understanding of strategies for personalized medication in Chinese patients with dyslipidemia.

Plasminogen Activator Inhibitor-1 (PAI-1) Gene Polymorphisms Associated with Cardiovascular Risk Factors Involved in Cerebral Venous Sinus Thrombosis

Cerebral venous sinus thrombosis (CVST), accounting for less than 1% of stroke cases, is characterized by various causes, heterogeneous clinical presentation and different outcome. The plasminogen activator inhibitor-1 (PAI-1) gene polymorphisms has been found to be associated with CVST. The aim of this retrospective study was to determine the potential association of PAI-1 675 4G/5G polymorphisms and homocysteine levels with cardiovascular risk factors in a group of young patients with CVST. Eighty patients with CVST and an equal number of age and sex matched controls were enrolled. The protocol included demographic and clinical baseline characteristics, neuroimagistic aspects, genetic testing (PAI-1 675 4G/5G polymorphisms), biochemical evaluation (homocysteine-tHcy, the lipid profile, blood glucose, glycohemoglobin-HbA1c, high-sensitive C-reactive protein-hsCRP) data, therapy and prognosis. The PAI-1 675 4G/5G gene polymorphisms were significantly correlated with increased homocysteine level (tHcy) (p < 0.05), higher total cholesterol (TC) (p < 0.05), low- density lipoprotein cholesterol (LDLc) (p = 0.05) and high- sensitive C- reactive protein (hsCRP) (p < 0.05) in patients with CVST when compared with controls. From the PAI-1 gene polymorphisms, the PAI-1 675 4G/5G genotype presented statistically significant values regarding the comparisons of the blood lipids values between the CVST group and control group. The homocysteine (tHcy) was increased in both groups, patients versus controls, in cases with the homozygous variant 4G/4G but the level was much higher in the group with CVST (50.56 µmol/L vs. 20.22 µmol/L; p = 0.03). The most common clinical presentation was headache (91.25%), followed by seizures (43.75%) and focal motor deficits (37.5%). The superior sagittal sinus (SSS) was the most commonly involved dural sinus (56.25%), followed by the lateral sinus (LS) (28.75%). Intima-media thickness (IMT) values were higher in the patients' group with CVST (0.95 mm vs. 0.88 mm; p < 0.05). The fatal outcome occurred 2.5% of the time. PAI-1 675 4G/5G gene polymorphisms and higher homocysteine concentrations were found to be significantly associated with CVST in young patients.

MTHFR Gene Polymorphisms and Cardiovascular Risk Factors, Clinical-Imagistic Features and Outcome in Cerebral Venous Sinus Thrombosis

Cerebral venous sinus thrombosis (CVST) as a severe neurological emergency, is represented by variable conditions in its clinic presentation, onset, risk factors, neuroimagistic features and outcome. The genetic polymorphism of the methylenetetrahydrofolate reductase (MTHFR) gene C677T and A1298C was associated with CVST. We aimed to characterize the prevalence of MTHFR gene polymorphisms associated with cardiovascular risk factors in the group of patients with CVST. Also, we studied additional causes associated with CVST including local infections, general infections, obstetric causes (pregnancy, puerperium) and head injury. This is a retrospective study including 114 patients which referred to our hospital between February 2012-February 2020. The protocol included demographic (age, sex), clinical, neuroimagistic features, paraclinic (genetic polymorphism of MTHFR, factor V G1691A-Leiden, prothrombin G20210A, PAI-1 675 4G/5G; Homocysteine level, the lipid profile, blood glucose and Glycohemoglobin HbA1c, high- sensitive C- reactive protein- hsCRP) data, as well as treatment and outcome. The mean age was 37.55 years with a female predominance (65.79%). In the first group of patients with inherited thrombophilia (60 cases; 52.63%) we found genetic mutation includes MTHFR C677T (38.59%) and A1298C (14.03%), factor V G1691A- Leiden (15.78%), prothrombin G20210A (2.63%), PAI-1 675 4G/5G (42.98%), and hyperhomocysteinemia (35.08%). At the second group with other etiology of CVST, except thrombophilia, we included 54 patients (47.36%). The most common sites of thrombosis were the superior sagittal sinus (52.63%). Headache was the most common symptom (91.22%) and seizures were the main clinical presentation (54.38%). The MTHFR polymorphism was significantly correlated with higher total cholesterol (TC) (p = 0.023), low- density lipoprotein cholesterol (LDL) (p = 0.008), homocysteine level (tHcy) (p < 0.001). Inside the first group with MTHFR polymorphism we have found a significant difference between the levels of homocysteine at the patients with MTHFR C677T versus MTHFR A1298C polymorphism (p < 0.001). The high-sensitive C-reactive protein (hsCRP) was increased in both groups of patients, but the level was much higher in the second group (p = 0.046). Mortality rate was of 2.63%. Demographic, clinical and neuroimagistic presentation of CVST in our study was similar with other studies on the matter, with a high frequency of thrombophilia causes. MTHFR gene polymorphisms (C677T and A1298C) are increased in prevalence in CVST. PAI-1 675 4G/5G gene mutation seems to be involved in CVST etiology. Plasma C-reactive protein level and hyperhomocysteinemia should be considered as a prognostic factor in CVST.

Association of the MTHFR 677C>T and 1298A>C polymorphisms and male infertility risk: a meta-analysis

BACKGROUND AND OBJECTIVES

One of the possible male sterility risk factors are polymorphisms of Methylenetetrahydrofolate reductase (MTHFR). However, the epidemiologic investigations described inconsistent results regarding MTHFR polymorphism and the risk of male infertility. For that reason, we carried out a meta-analysis of published case-control studies to re-examine the controversy.

METHODS

Electronic searches of Cochrane, EMBASE, Google Scholar, and PubMed were conducted to select eligible studies for this meta-analysis (updated to May 2019). According to our exclusion and inclusion criteria, only high-quality studies that remarked the association between MTHFR polymorphisms and male infertility risk were included. The Crude odds ratio (OR) with a confidence interval of 95% (CI) was used to assess the relationship between MTHFR polymorphism and male infertility risk.

RESULTS

Thirty-four case-control studies with 9662 cases and 9154 controls concerning 677C/T polymorphism and 22 case-control studies with 5893 cases and 6303 controls concerning 1298A/C polymorphism were recruited. Both MTHFR polymorphisms had significant associations with male infertility risk (CT + TT vs. CC: OR = 1.37, 95% CI: 1.21-1.55, P = 0.00, I² = 41.9%); (CC vs. CA + AA: OR = 0.82, 95% CI: 0.52-1.30, P = 0.04, I² = 50.1%). Further, when stratified by ethnicity, the significant association results were observed in Asians and Caucasians for 677C/T and just Asians for 1298A/C.

CONCLUSIONS

Some of MTHFR polymorphisms like MTHFR 677C > T are associated with an elevated male infertility risk. To confirm our conclusion and to provide more accurate and complete gene-environment communication with male infertility risk, more analytical studies are needed.

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.

Effects of methionine synthase and methionine synthase reductase polymorphisms on hypertension susceptibility

BACKGROUND

Polymorphisms of methylenetetrahydrofolate reductase (MTHFR) gene are strongly associated with hypertension incidence, although such association is inconsistent among ethnicities studied. However, effects of polymorphisms of other genes related to folate metabolism besides MTHFR on hypertension susceptibility are not well known yet.

OBJECTIVE

The aim of this study was to elucidate whether methionine synthase (MTR) 2756A>G and methionine synthase reductase (MTRR) 66A>G polymorphisms might be associated with risks of hypertension susceptibility in the Korean population.

METHODS

Genotyping of these two polymorphisms was performed for 232 hypertensive patients and 247 unrelated healthy controls using polymerase chain reaction-restriction fragment length polymorphism technique.

RESULTS

In the present study, mutations of MTR 2756A>G and MTRR 66A>G polymorphisms were associated with increased and decreased susceptibility to hypertension, respectively. Allele combinations from these two polymorphisms were also related to hypertension prevalence. When polymorphism data were stratified according to clinical components of hypertension, The G allele of MTR 2756A>G polymorphism was significantly associated with an increased risk of hypertension in subjects with BMI < 26.1 kg/m² (P = 0.004), WC < 87.2 in. (P = 0.021), FBG < 95.5 mg/dL (P = 0.011), triglyceride < 133.5 mg/dL (P = 0.034), and HDL-cholesterol < 52.2 mg/dL (P = 0.036). The G allele of MTRR 66A>G polymorphism was significantly associated with a decreased risk of hypertension in subjects with WC ≥ 87.2 in. (P = 0.029), FBG ≥ 95.5 mg/dL (P = 0.032) and triglyceride ≥ 133.5 mg/dL (P = 0.027).

CONCLUSION

MTR 2756A>G and MTRR 66A>G polymorphisms related to folate metabolism might be genetic markers for risk of hypertension in the Korean population.

Association of the MTHFR 677C>T Polymorphism with Obesity and Biochemical Variables in a Young Population of Mexico

BACKGROUND

Methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms have been associated with overweight people and obesity. The goal of this study was to investigate the relationship of the MTHFR 677C>T polymorphism with obesity and biochemical variables in young individuals of Mexico.

METHODS

A total of 316 young individuals were included in the study, 172 with normal weight (NW) and 144 with over weight/obesity. Body mass index (BMI) was classified as NW, overweight, and obesity. Also, waist circumference was measured. Moreover, glucose, total cholesterol, and triglycerides were determined. Genotyping for MTHFR 677C>T polymorphism was performed by the PCR-RFLP method.

RESULTS

There was no difference in the distribution of the MTHFR 677C>T polymorphism between individuals with NW and overweight/obesity; neither when they were divided by overweight vs NW, nor when we contrasted obese vs NW. However, an analysis stratified by gender showed a significant protector effect of the TT genotype against obesity in males and elevated waist circumference in females. Also, overweight/obese individuals with TT genotype had less risk of high cholesterol or triglycerides than overweight/obese subjects with the other genotypes.

CONCLUSIONS

These results suggest that the MTHFR 677T polymorphism might not be a risk factor for being overweight/obesity. Rather, on the basis of our results, this variant could be a protector effect. However, further large-scale population-based studies are still necessary to clarify the role of the MTHFR 677C>T polymorphism in overweight, obesity, and lipid profile level.

Interactions between genetic variants involved in the folate metabolic pathway and serum lipid, homocysteine levels on the risk of recurrent spontaneous abortion

Background

The interaction between folate pathway gene polymorphisms and homocysteine, serum lipid leverls are poorly understood in patients with recurrent spontaneous abortion (RSA). The aim of this study is to explore the effects of folate pathway gene polymorphisms (the 5–10-methylenetetrahydrofolate reductase, MTHTR C677T, MTHFR A1298C and the methionine synthase reductase, MTRR A66G) and their interactions with homocysteine on serum lipid levels in patients with RSA.

Methods

A total of 403 RSA women and 342 healthy women were randomly selected. Genotyping of the MTHFR C677T, A1298C and MTRR A66G were performed by TaqMan-MGB technique. Serum homocysteine, folate, fasting glucose, fasting insulin, Interleukin 6, Tumor necrosis factorα (TNFα) and lipid profiles were measured according to the kits. Continuous variables were analyzed using 2-sample t-tests. Categorical variables were analyzed and compared by χ² or Fisher’s exact tests. Unconditional logistic regression model was applied to test the interactions of gene polymorphisms on RSA.

Results

The distribution of genotype of CC, CT TT and T allele of MTHFR C677T, genotype of AA and C allele of MTHFR A1298C, and genotype of AA, AG and G allele of MTRR A66G were different between cases and controls (all p were < 0.05). There were significant interactions between MTHFR C677T-A1298C and MTHFR A1298C-MTRR A66G in RSA group and control group, with ORs of 1.62 (95%CI: 1.28–2.04, p < 0.001) and 1.55 (95%CI: 1.27–1.88, p < 0.001), respectively. Serum TNFα level and insulin resistant status (HOMR-IR) were higher in RSA group than in control group (p = 0.038, 0.001, respectively). All the three gene SNPs except MTRR 66AG gene variant had detrimental effects on HOMA-IR (all p were < 0.05). RSA group who carried the MTHFR 677CT, TT, CT/TT genotypes and MTRR 66AG, AG/GG genotypes had detrimental effects on serum homocysteine levels, the MTHFR 677CT, CT/TT genotype carriers had favorable effects on serum folate levels, the MTHFR 677TT, CT/TT, 1298 AC, AC/CC genotype carriers had detrimental effects on serum low-density lipoprotein cholesterol (LDL-C) levels, and the MTRR 66AG genotype carriers had lower high-density lipoprotein cholesterol (HDL-C) levels than the AA genotype carriers (all p were < 0.05).

Conclusions

Interaction between the MTHFR C677T, A1298C and MTHFR A1298C, MTRR A66G are observed in our RSA group. Besides, all the three gene SNPs except MTRR 66AG gene variant had detrimental effects on HOMA-IR. MTHFR C677T and MTRR A66G gene variants had detrimental effects on serum homocysteine levels and insulin resistance status, while MTHFR C677T, A1298C and MTRR A66G gene variants had detrimental effects on certain serum lipid profiles.

Associations of homocysteine status and homocysteine metabolism enzyme polymorphisms with hypertension and dyslipidemia in a Chinese hypertensive population

Background: Hypertension (HTN), dyslipidemia and hyperhomocysteinemia (HHcy) are risk factors for cardiovascular disease (CVD).Methods: Hypertensive Chinese subjects (n = 228) were enrolled. MTHFR C667T, MTHFR A1298C, MTR A2756G, and MTRR A66G genotypes were determined. Unconditional logistic regression was performed to determine the associations of serum Hcy status and genotypes with HTN and dyslipidemia.Results: The mean age of hypertensive adults was 65.53 ± 9.94 years, including 88 (38.6%) men and 140 (61.4%) women. Patients with MTHFR 667TT and MTRR GG carriers showed higher serum Hcy levels (P = 0.019 and 0.018, respectively), which is associated with higher serum triacylglycerols (TAG) and total cholesterol (TC) levels (P = 0.014 and 0.044, respectively) and a higher risk for hypertriglyceridemia (OR = 1.889, 95% CI: 1.105-3.229, P = 0.020). Compared with low Hcy and MTRR 66AA, those with high Hcy and 66AA or 66AG+GG showed higher odd\s of hypertriglyceridemia (MTRR 66AA+ high Hcy: OR: 2.692, 95% CI: 1.189-6.096, Pcombined = 0.018; MTRR 66AG/GG+ high Hcy: OR: 3.433, 95% CI: 1.517-7.772, Pcombined = 0.003, respectively). Patients with high Hcy and MTHFR 667CC, as well as those with low Hcy and 667CT+TT, showed lower odds of uncontrolled SBP (MTHFR 667CC+ high Hcy: OR: 0.338, 95% CI: 0.115-0.996, Pcombined = 0.049; MTHFR 667CT/TT+ low Hcy: OR: 0.421, 95% CI: 0.193-0.921, Pcombined = 0.030) compared to patients with low Hcy and MTHFR 667CC.Conclusions: Serum Hcy status and Hcy metabolism gene polymorphisms (MTHFR C667T and MTRR A66G) may have synergistic effects on the prevalence of HTN and dyslipidemia.

Associations of the MTHFR rs1801133 polymorphism with coronary artery disease and lipid levels: a systematic review and updated meta-analysis

BACKGROUND

The associations of the 5,10-methylenetetrahydrofolate reductase gene (MTHFR) rs1801133 polymorphism with coronary artery disease (CAD) and plasma lipid levels have been widely investigated, but the results were inconsistent and inconclusive. This meta-analysis aimed to clarify the relationships of the rs1801133 polymorphism with CAD and plasma lipid levels.

METHODS

By searching in PubMed, Google Scholar, Web of Science, Cochrane Library, Wanfang, VIP and CNKI databases, 123 studies (87,020 subjects) and 65 studies (85,554 subjects) were identified for the CAD association analysis and the lipid association analysis, respectively. Odds ratio (OR) and standardized mean difference (SMD) were used to determine the effects of the rs1801133 polymorphism on CAD risk and lipid levels, respectively.

RESULTS

The variant T allele of the rs1801133 polymorphism was associated with increased risk of CAD under allelic model [OR = 1.11, 95% confidence interval (CI) = 1.06-1.17, P < 0.01], additive model (OR = 1.25, 95% CI = 1.14-1.37, P < 0.01), dominant model (OR = 1.11, 95% CI = 1.04-1.17, P < 0.01), and recessive model (OR = 1.22, 95% CI = 1.12-1.32, P < 0.01). The T carriers had higher levels of total cholesterol (TC) (SMD = 0.04, 95% CI = 0.01-0.07, P = 0.02) and low-density lipoprotein cholesterol (LDL-C) (SMD = 0.07, 95% CI = 0.01-0.12, P = 0.01) than the non-carriers.

CONCLUSIONS

The meta-analysis suggested that the T allele of the rs1801133 polymorphism is a risk factor for CAD, which is possibly and partly mediated by abnormal lipid levels.

Influence of the C677T Polymorphism of the MTHFR Gene on Oxidative Stress in Women With Overweight or Obesity: Response to a Dietary Folate Intervention

The C677T polymorphism of the methylenetetrahydrofolate reductase gene (MTHFR) is related to folate metabolism and can alter the levels of biochemical markers.Objective: Investigate the influence of the MTHFR C677T polymorphism on the effects of a dietary folate intervention on oxidative stress in women with overweight or obesity.Methods: Forty-eight adult women with overweight or obesity were subjected to a 24-hour dietary recall, anthropometric measurements, biochemical analysis, and genotyping of the MTHFR C677T polymorphism. They were allocated by convenience sampling to 2 groups, which received 300 g of folate-rich vegetables containing 191 µg/d (Group 1) (n = 24) or 95 µg/d (Group 2) (n = 24) of folate for 8 weeks.Results: The dietary intervention increased the serum folic acid levels in the 2 analyzed groups. The intervention with 191 µg/d of folate led to relevant results in terms of homocysteine levels (p = 0.0005) and total antioxidant capacity (p = 0.0261); the effect was larger among carriers of the TT genotype.Conclusions: The study demonstrated the beneficial effect of folate intake in terms of a TAC elevation for the CC and TT genotypes of the MTHFR C677T polymorphism, an increase in folic acid levels for all genotypes, and a reduction in the Hcy levels for the TT genotype in response to an intervention consisting of an intake of 191 µg/d of folate supplied by vegetables.

Vulnerability of the frontal and parietal regions in hypertensive patients during working memory task

BACKGROUND

Hypertension is related with cognitive decline in the elderly. The frontal-parietal executive system plays an important role in cognitive aging and is also vulnerable to damage in elderly patients with hypertension. Examination of the brain's functional characteristics in frontal-parietal regions of hypertension is likely to be important for understanding the neural mechanisms of hypertension's effect on cognitive aging.

METHODS

We address this issue by comparing hypertension and control-performers in a functional MRI study. Twenty-eight hypertensive patients and 32 elderly controls were tested with n-back task with two load levels.

RESULTS

The hypertensive patients exhibited worse executive and memory abilities than control subjects. The patterns of brain activation changed under different working memory loads in the hypertensive patients, who exhibited reduced activation only in the precentral gyrus under low loads and reduced activation in the middle frontal gyrus, left medial superior frontal gyrus and right precuneus under high loads. Thus, more regions of diminished activation were observed in the frontal and parietal regions with increasing task difficulty. More importantly, we found that lower activation in changed frontal and parietal regions was associated with worse cognitive function in high loads.

CONCLUSION

The results demonstrate the relationship between cognitive function and frontoparietal functional activation in hypertension and their relevance to cognitive aging risk. Our findings provide a better understanding of the mechanism of cognitive decline in hypertension and highlight the importance of brain protection in hypertension.

Gender-specific interactions of MTHFR C677T and MTRR A66G polymorphisms with overweight/obesity on serum lipid levels in a Chinese Han population

Background

Little is known regarding the interactions of methylenetetrahydrofolate reductase (MTHFR) C677T and methionine synthase reductase (MTRR) A66G polymorphisms with overweight/obesity on serum lipid profiles. The aim of the current study was to explore interactions between the two polymorphisms and overweight/obesity on four common lipid levels in a Chinese Han population and further to evaluate whether these interactions exhibit gender-specificity.

Methods

A total of 2239 participants (750 females and 1489 males) were enrolled into this study. The genotypes of the MTHFR C677T and MTRR A66G were determined by a TaqMan assay. Overweight and obesity were defined as a body mass index between 24 and 27.99 and ≥ 28 kg/m², respectively. The interactions were examined by factorial design covariance analysis, and further multiple comparisons were conducted by Bonferroni correction.

Results

There was no significant difference in the genotypic and allelic frequencies between females and males (MTHFR 677 T allele: 54.47 % for females and 54.40 % for males; MTRR 66G allele: 24.73 % for females and 24.71 % for males). Interaction between the MTHFR C677T polymorphism and overweight/obesity on serum triglyceride levels, and interaction between the MTRR A66G polymorphism and overweight/obesity on serum high-density lipoprotein cholesterol levels were detected in women (P = 0.015 and P = 0.056, respectively). For female subjects with overweight/obesity, the serum triglyceride levels in MTHFR 677TT genotype [1.09 (0.78–1.50) mmol/L] were significantly higher as compared with MTHFR 677CC genotype [0.90 (0.60–1.15) mmol/L, P = 0.007], and the MTRR 66GG genotype carriers had higher serum high-density lipoprotein cholesterol levels than those with MTRR 66AG genotype (1.46 ± 0.50 vs. 1.19 ± 0.31 mmol/L, P = 0.058). Furthermore, in male subjects with overweight/obesity, the MTHFR 677CT genotype carriers had higher low-density lipoprotein cholesterol levels than those with MTHFR 677TT genotype (2.96 ± 1.07 vs. 2.74 ± 0.88 mmol/L, P = 0.015).

Conclusions

Our results indicate that there exist interactive effects of the MTHFR C677T and MTRR A66G polymorphisms with overweight/obesity on some lipid traits in Chinese Han population, and the effects were gender-specific.

Individual and Joint Associations of Methylenetetrahydrofolate Reductase C677T Genotype and Plasma Homocysteine With Dyslipidemia in a Chinese Population With Hypertension

We aimed to examine the cross-sectional associations of plasma total homocysteine (tHcy) concentrations and methylenetetrahydrofolate reductase ( MTHFR) C677T genotype with dyslipidemia. A total of 231 patients with mild-to-moderate essential hypertension were enrolled from the Huoqiu and Yuexi communities in Anhui Province, China. Plasma tHcy levels were measured by high-performance liquid chromatography. Genotyping was performed by TaqMan allelic discrimination technique. Compared with MTHFR 677 CC + CT genotype carriers, TT genotype carriers had higher odds of hypercholesterolemia (adjusted odds ratio [OR] [95% confidence interval (CI)]: 2.7 [1.4-5.2]; P = .004) and higher odds of abnormal low-density lipoprotein cholesterol (adjusted OR [95% CI]: 2.3 [1.1-4.8]; P = .030). The individuals with the TT genotype had higher concentrations of log(tHcy) than those with the 677 CC + CT genotype (adjusted β [standard error]: .2 [0.03]; P < .001). Patients with tHcy ≥ 10 μmol/L had significantly higher odds of hypercholesterolemia (adjusted OR [95% CI]: 2.4 [1.2-4.7]; P = .010). Furthermore, patients with both the TT genotype and the tHcy ≥ 10 μmol/L had the highest odds of hypercholesterolemia (adjusted OR [95% CI]: 4.1 [1.8-9.4]; P = .001) and low-density lipoprotein cholesterol (adjusted OR [95% CI]: 2.4 [1.0-6.0]; P = .064). This study suggests that both tHcy and the MTHFR C677T gene polymorphism may be important determinants of the incidence of dyslipidemia in Chinese patients with essential hypertension. Further studies are needed to confirm the role of tHcy and the MTHFR C677T mutation in the development of dyslipidemia in a larger sample.

Disrupted white matter structure underlies cognitive deficit in hypertensive patients

OBJECTIVES

Hypertension is considered a risk factor of cognitive impairments and could result in white matter changes. Current studies on hypertension-related white matter (WM) changes focus only on regional changes, and the information about global changes in WM structure network is limited.

METHODS

We assessed the cognitive function in 39 hypertensive patients and 37 healthy controls with a battery of neuropsychological tests. The WM structural networks were constructed by utilizing diffusion tensor tractography and calculated topological properties of the networks using a graph theoretical method. The direct and indirect correlations among cognitive impairments, brain WM network disruptions and hypertension were analyzed with structural equation modelling (SEM).

RESULTS

Hypertensive patients showed deficits in executive function, memory and attention compared with controls. An aberrant connectivity of WM networks was found in the hypertensive patients (P Eglob = 0.005, P Lp = 0.005), especially in the frontal and parietal regions. Importantly, SEM analysis showed that the decline of executive function resulted from aberrant WM networks in hypertensive patients (p = 0.3788, CFI = 0.99).

CONCLUSIONS

These results suggest that the cognitive decline in hypertensive patients was due to frontal and parietal WM disconnections. Our findings highlight the importance of brain protection in hypertension patients.

KEY POINTS

• Hypertension has a negative effect on the performance of the cognitive domains • Reduced efficiencies of white matter networks were shown in hypertension • Disrupted white matter networks are responsible for poor cognitive function in hypertension.

Disrupted Frontoparietal Network Mediates White Matter Structure Dysfunction Associated with Cognitive Decline in Hypertension Patients

Some previous reports have suggested that hypertension is a risk factor for dementia and cognitive impairments. Using behavioral data from 1007 elderly human subjects (405 hypertensive patients) of Han ethnicity from Beijing, China, the present study aimed to assess the effects of hypertension on cognitive performance and explore related neuronal changes via advanced resting-state functional magnetic resonance imaging and diffusion tensor imaging data from 84 of these subjects (44 hypertensive patients). Cognitively, we found that patients with hypertension showed decreased executive functions and attention compared with those with normotension in the large sample. In magnetic resonance imaging scan sample, using independent component analysis to examine the functional connectivity difference between the two groups, we found that the frontoparietal networks in the hypertensive group exhibited altered patterns compared with the control group, mainly in the inferior parietal lobe, left inferior frontal lobe, and precuneus. Using tract-based spatial statistics to investigate the between-group structural difference, we found that the hypertensive group showed significantly reduced integrity of white matter in the bilateral superior longitudinal fasciculus. Importantly, using the mediation analysis, we found that the functional connectivity of the frontoparietal networks mediates the impact of white matter on executive function in the hypertensive group. The results demonstrate that hypertension targets a specific pattern of cognitive decline, possibly due to deficits in the white matter and functional connectivity in frontal and parietal lobes. Our findings highlight the importance of brain protection in hypertension.

SIGNIFICANCE STATEMENT

Hypertension is a risk factor for cognitive decline and dementia. However, the neural mechanism underlying cognitive decline in hypertension is largely unknown. We studied the relationship among cognitive decline, brain functional, and structural changes in hypertensive patients via advanced resting-state functional magnetic resonance imaging and diffusion tensor imaging data in a Chinese cohort. Hypertensive patients showed executive dysfunction, along with disrupted functional connectivity in frontoparietal (FP) networks and reduced integrity of white matter in the bilateral superior longitudinal fasciculus. Importantly, the functional connectivity changes mediate the impact of white matter alterations on cognitive decline in the hypertensive group. Our findings provide a better understanding of the mechanism of cognitive decline in hypertension and highlight the importance of brain protection in hypertension.

Joint associations of folate, homocysteine and MTHFR, MTR and MTRR gene polymorphisms with dyslipidemia in a Chinese hypertensive population: a cross-sectional study

BACKGROUND

Dyslipidemia is a well-established risk factor for cardiovascular disease. Serum lipids were affected by several gene polymorphisms, folate, homocysteine and other metabolite levels. We aim to investigate the effects of homocysteine metabolism enzyme polymorphisms (MTHTR C677T, MTHFR A1298C, MTR A2756G and MTRR A66G) and their interactions with folate, homocysteine on serum lipid levels in Chinese patients with hypertension.

METHODS

Participants were 480 hypertensive adults that enrolled in September to December 2005 from six different Chinese hospitals (Harbin, Shanghai, Shenyang, Beijing, Xi'an, and Nanjing). Known MTHFR C677T, MTHFR A1298C, MTR A2756G and MTRR A66G genotypes were determined by PCR-RFLP methods. Serum folate was measured by chemiluminescent immunoassay, homocysteine was measured by high-performance liquid chromatography, serum lipids parameters were determined by an automatic biochemistry analyzer, low-density lipoprotein was calculated by Friedewald's equation. Unitary linear regression model was used to assess the associations of gene polymorphisms, folate and homocysteine on serum lipid profiles. Unconditional logistic regression model was applied to test the interactions of folate, homocysteine and gene polymorphisms on dyslipidemia.

RESULTS

No correlations between gene polymorphisms and homocysteine on serum lipid profiles. Compared with normal folate patients, patients with low folate showed higher odds of hypertriglyceridemia (OR = 2.02, 95 % CI: 1.25-3.25, P = 0.004) and low levels of high-density lipoprotein cholesterol (OR = 1.88, 95 % CI: 1.07-3.28, P = 0.027). Each of four gene polymorphisms (MTHTR C677T, MTHFR A1298C, MTR A2756G and MTRR A66G) combined with low folate showed higher odds of hypertriglyceridemia (P for trend: 0.049, 0.004, 0.007 and 0.005, respectively). MTHFR C677T and A1298C with low folate showed higher odds of low levels of high-density lipoprotein cholesterol (P for trend: 0.008 and 0.031).

CONCLUSIONS

Low folate status and homocysteine metabolism gene polymorphisms (MTHTR C677T, MTHFR A1298C, MTR A2756G and MTRR A66G) may have a synergistic effect increased the incidence of dyslipidemia in Chinese hypertensive population.

Associations of MTHFR C677T and MTRR A66G gene polymorphisms with metabolic syndrome: a case-control study in Northern China

Prior evidence indicates that homocysteine plays a role in the development of metabolic syndrome (MetS). Methylenetetrahydrofolate reductase (MTHFR) C677T and methionine synthase reductase (MTRR) A66G polymorphisms are common genetic determinants of homocysteine levels. To investigate the associations of the MTHFR C677T and MTRR A66G polymorphisms with MetS, 692 Chinese Han subjects with MetS and 878 controls were recruited. The component traits of MetS and the MTHFR C677T and MTRR A66G genotypes were determined. A significant association was observed between the MTHFR 677T allele and increased risk of MetS, high fasting blood glucose, high waist circumference, and increasing number of MetS components. The MTRR A66G polymorphism was associated with an increased risk of MetS when combined with the MTHFR 677TT genotype, although there was no association found between MetS and MTRR A66G alone. Furthermore, the MTRR 66GG genotype was associated with high fasting blood glucose and triglycerides. Our data suggest that the MTHFR 677T allele may contribute to an increased risk of MetS in the northern Chinese Han population. The MTRR A66G polymorphism is not associated with MetS. However, it may exacerbate the effect of the MTHFR C677T variant alone. Further large prospective population-based studies are required to confirm our findings.

Association of COMT G675A and MTHFR C677T polymorphisms with hypertensive disorders of pregnancy in Mexican mestizo population

OBJECTIVE

To investigate the relationship between COMT G675A and MTHFR C677T polymorphisms and hypertension disorders of pregnancy (HDP) in a Mexican mestizo population.

DESIGN AND METHODS

This case-control study involved 194 HDP and 194 normoevolutive pregnant women. The polymorphisms were genotyped by real time PCR.

RESULTS

Our results showed that the COMT AA genotype increases the risk to HDP (OR: 2.67; 95% CI 1.33-5.35), preeclampsia (OR: 2.69; 95% CI 1.00-7.22) and gestational hypertension (OR: 3.87; 95% CI 1.25-12.0). Furthermore, the double mutant genotype (COMTAA/MTHFRTT) potency the risk to HDP more than two times (OR: 5.21; 95% CI 1.12-24.3, p=0.019).

CONCLUSION

Our work provides evidence that COMT 675AA genotype is a risk factor for HDP and that this risk is increased by the presence of MTHFR 677TT genotype in a Mexican mestizo population.