An unusually high plasma concentration of homocysteine resulting from a combination of so-called "secondary" etiologies.

The metabolism of homocysteine is complex and involves many enzymes as well as vitamin-derived cofactors. Any dysregulation of this metabolism may lead to hyperhomocysteinemia (HHCy) which is responsible for many clinical disorders including thromboembolic events. HHCy may result from very different etiologies and is generally classified into three groups according to homocysteine concentrations: moderate (<30 µmol/L), intermediate (30-100 µmol/L) or major (>100 µmol/L). Major HHCy cases are generally due to monogenic defects of key enzymes involved in homocysteine metabolism, such as cystathionine-ß-synthase or 5,10-methylene-tetrahydrofolate reductase, or to any defect in vitamin B12 absorption, transport or metabolism. By contrast, moderate and intermediate HHCy tend to result from so-called "secondary" etiologies (e.g. tobacco, drugs, alcohol, vitamin deficiencies or pathological contexts). Here we describe the case of a patient with an unusually high plasma homocysteine concentration (1562 µmol/L) which was only explained by a combination of such secondary etiologies, among them chronic renal failure, hypothyroidism, the homozygous C677T MTHFR variant, a novel heterozygous variant of the MSR gene, and a vitamin deficiency. In addition, this patient exhibited a spectacular decline in homocysteine concentrations (returning to normal) after betaine and vitamin administration. In conclusion, this case highlights that major HHCy may also result from the combination of secondary etiologies, with vitamin deficiency as a triggering factor.

Evaluation of methylenetetrahydrofolate reductase (MTHFR) activity and the levels of homocysteine and malondialdehyde (MDA) in the serum of women with preeclampsia.

BACKGROUND: Methylenetetrahydrofolate reductase (MTHFR) has a key role in converting homocysteine to methionine so its deficiency might cause homocysteine accumulation and arterial destruction. The aim of this study was to evaluate the activity of methylenetetrahydrofolate reductase (MTHFR), homocysteine, and MDA levels in preeclampsia patients. MATERIAL AND METHODS: In this case-control study, 30 preeclampsia patients and 30 healthy pregnant women as control group were selected and matched for maternal age, gestational age, and BMI. Preeclampsia was confirmed by examining hypertension and urinary proteinuria. Serum homocysteine and MDA level as well as MTHFR activity were measured manually. RESULTS: Homocysteine and MDA levels were significantly different between women with preeclampsia and normal pregnancies (p-value <0.001). Also, the results indicate that MTHFR activity in the two groups was statistically different (p-value <0.001). CONCLUSION: It can be concluded that the regulation of homocysteine and its metabolic enzymes plays a significant role in controlling blood pressure and consequently in the pathophysiology of Preeclampsia and it can be a goal for prevention and treatments.

5-Methyltetrahydrofolate reduces blood homocysteine level significantly in C677T methyltetrahydrofolate reductase single-nucleotide polymorphism carriers consulting for infertility.

PURPOSE: Methyltetrahydrofolate reductase (MTHFR) C677T (ala222Val) is a single-nucleotide polymorphism (SNP) that affects the formation of 5-methyltetrahydrofolate (5-MTHF), the active folate that allows the recycling of homocysteine (Hcy) to Methionine. Hcy is at the epicentre of oxidative stress and DNA methylation errors. This SNP often increases the circulating Hcy levels and consequently reduces the methylation process, which is involved in the epigenesis and imprinting of markings in gametes. This study aimed to investigate decreases in Hcy levels in MTHFR SNP carriers. PROCEDURE: Eighty-nine couples with fertility problems for at least 3 years were included in this program. The women were systematically tested for the MTHFR C 677T isoform. If the woman tested positive, testing of the male partner was proposed. All the carriers had well-controlled blood Hcy levels before and after treatment (600µg of 5-MTHF/day, with a backup of one carbon cycle during at least 3 months). FINDINGS: As expected, the circulating Hcy level was higher in the homozygous patients than in the heterozygous and wild-type patients. The treatments caused a significant decrease of the circulating Hcy in the SNP carriers group. CONCLUSIONS: Couples with a long history of infertility should be analysed for MTHFR SNP and homocysteine and should be treated with physiological doses of 5-MTHF instead of high doses of folic acid.

Low folate status, and MTHFR 677C > T and MTR 2756A > G polymorphisms associated with colorectal cancer risk in Thais: a case-control study.

Folate plays essential roles in DNA synthesis, repair, and methylation; thus, folate status may affect carcinogenesis. Genetics polymorphisms involved in folate metabolisms have been linked with colorectal cancer (CRC) development. Therefore, we hypothesized that low folate status and related genetic polymorphisms are associated with higher risk of CRC. This case-control study enrolled 105 new cases of CRC, 101 of colorectal adenoma (CRA), and 182 controls from hospitals in Bangkok, Thailand, to examine the association between folate status and methylenetetrahydrofolate reductase (MTHFR) 677C > T, methionine synthase (MTR) 2756A > G, and methionine synthase reductase (MTRR) 66A > G with the risk of CRC and CRA. Regarding CRC risk, the lowest quartile group of serum folate and folate intake had higher risk of CRC than the highest quartile group (odds ratio [OR] = 11.45, 95% confidence interval [CI] = 4.43-29.59) and (OR = 10.29, 95% CI = 4.17-25.41). The lowest quartile group of folate intake also had a higher risk of CRA (OR = 5.22, 95% CI = 2.19-6.09). Low red blood cell folate combined with MTHFR 677C > T polymorphism statistically increased CRC risk (OR = 10.00, 95% CI = 1.36-73.42). Low folate status combined with MTR 2756A > G significantly increased CRA risk (OR = 6.43, 95% CI = 1.38-29.94). Moreover, the risk of CRC was elevated with alcohol consumption and low exercise activity when combined with low folate status (P < .05). This study supported the hypothesis that, in Thais, low folate status is associated with a higher risk of CRC, particularly among those with polymorphisms of the MTHFR 677C > T and MTR 2756 A > G genes.

Association of plasma homocysteine level with vaso-occlusive crisis in sickle cell anemia patients of Odisha, India.

Vascular complications of sickle cell anemia (SCA) are influenced by many factors. Elevated plasma homocysteine (Hcy) is supposed to be an independent risk factor and is either genetic or nutritional origin. The present study evaluated the plasma Hcy level, MTHFR C677T gene polymorphism, effect of folic acid (FA) supplementation' and hemato-biochemical parameters in SCA and their effect on the vaso-occlusive crisis (VOC) in SCA patients of an Asian-Indian haplotype population. One hundred twenty cases of SCA (HbSS) and 50 controls with normal hemoglobin(HbAA) were studied. It was found that the plasma Hcy level is significantly higher (p < 0.0001) in patients with SCA (22.41 ± 7.8 µmol/L) compared to controls (13.2 ± 4.4 µmol/L). Moreover, patients without FA supplementation had a significantly (p < 0.001) higher Hcy level (27 ± 7 µmol/L) compared to those with supplementation (17.75 ± 5.7 µmol/L). Turkey-Kramer multiple comparison tests show that there is a significant difference (p < 0.05) in HbF percent, hemoglobin (Hb), platelet count, serum bilirubin (direct:Bil-D and total:Bil-T), aspartate transaminase (AST), lactate dehydrogenase (LDH), and plasma Hcy levels between mild and severe VOC. Between moderate VOC and severe VOC, there was a significant difference (p < 0.05) in HbF%, Bil-D, AST, Hcy. Pearson correlation revealed that plasma Hcy had a significantly (p < 0.05) positive correlation with AST, serum bilirubin (indirect and total), LDH, jaundice, stroke, VOC per year, and hospitalization per year whereas it was inversely correlated with HbF percentage, Hb level, and FA treatment. In the study population, increased plasma Hcy level, hemolysis, and platelet activation were found to influence VOC in SCA.

Folate, genomic stability and colon cancer: The use of single cell gel electrophoresis in assessing the impact of folate in vitro, in vivo and in human biomonitoring.

Intake of folate (vitamin B9) is strongly inversely linked with human cancer risk, particularly colon cancer. In general, people with the highest dietary intake of folate or with high blood folate levels are at a reduced risk (approx. 25%) of developing colon cancer. Folate acts in normal cellular metabolism to maintain genomic stability through the provision of nucleotides for DNA replication and DNA repair and by regulating DNA methylation and gene expression. Folate deficiency can accelerate carcinogenesis by inducing misincorporation of uracil into DNA, by increasing DNA strand breakage, by inhibiting DNA base excision repair capacity and by inducing DNA hypomethylation and consequently aberrant gene and protein expression. Conversely, increasing folate intake may improve genomic stability. This review describes key applications of single cell gel electrophoresis (the comet assay) in assessing genomic instability (misincorporated uracil, DNA single strand breakage and DNA repair capacity) in response to folate status (deficient or supplemented) in human cells in vitro, in rodent models and in human case-control and intervention studies. It highlights an adaptation of the SCGE comet assay for measuring genome-wide and gene-specific DNA methylation in human cells and colon tissue.

Association of Folate and Vitamins Involved in the 1-Carbon Cycle with Polymorphisms in the Methylenetetrahydrofolate Reductase Gene (MTHFR) and Global DNA Methylation in Patients with Colorectal Cancer.

Folate, vitamin B2, vitamin B6, vitamin B12, choline, and betaine are nutrients involved in the 1-carbon cycle that can alter the levels of DNA methylation and influence genesis and/or tumor progression. Thus, the objective of this study was to evaluate the association of folate and vitamins involved in the 1-carbon cycle and MTHFR polymorphisms in global DNA methylation in patients with colorectal cancer gene. The study included 189 patients with colorectal adenocarcinoma answering a clinical evaluation questionnaire and the Food Frequency Questionnaire (FFQ) validated for patients with colon and rectal cancer. Blood samples were collected for evaluation of MTHFR gene polymorphisms in global DNA methylation in blood and in tumor. The values for serum folate were positively correlated with the equivalent total dietary folate (total DFE) (rho = 0.51, p = 0.03) and global DNA methylation (rho = 0.20, p = 0.03). Individuals aged over 61 years (p = 0.01) in clinicopathological staging III and IV (p = 0.01) and with + heterozygous mutated homozygous genotypes for the MTHFR A1298C gene had higher levels of global DNA methylation (p = 0.04). The association between dietary intake of folate, serum folate, and tumor stage were predictive of global DNA methylation in patients' blood. The levels of serum folate, the dietary folate and the status of DNA methylation can influence clinicopathological staging.

Plasma B-vitamins and one-carbon metabolites and the risk of breast cancer in younger women.

PURPOSE: We examined the association of plasma B-vitamins and metabolites, and related genetic variants, with risk of breast cancer among predominantly premenopausal women. METHODS: We conducted a nested case-control study within the Nurses' Health Study II. From blood samples collected in 1996-1999 and follow-up through 2007, plasma measures were available for 610 cases and 1207 controls. Unconditional multivariable logistic regression was used to estimate relative risks (RR) of breast cancer and 95% confidence intervals (CIs). We examined whether associations varied by methylenetetrahydrofolate reductase (MTHFR) and dihydrofolate reductase polymorphisms, breast cancer risk factors, or tumor characteristics. RESULTS: Plasma vitamin B12 was associated with a 64% higher risk of breast cancer comparing the highest versus lowest quintile (95% CI 1.17-2.29, p-trend = 0.02). Plasma folate (comparable RR = 1.18, 95% CI 0.84-1.66), pyridoxal 5'-phosphate (RR = 1.18, 95% CI 0.85-1.64), homocysteine (RR = 0.93, 95% CI 0.67-1.28), cysteine (RR = 1.14, 95% CI 0.81-1.62), and cysteinylglycine (RR = 0.93, 95% CI 0.66-1.31) were not associated with overall breast cancer risk. Folate was significantly positively associated with invasive and estrogen receptor-positive/progesterone receptor-positive breast cancer, and this association was suggestively stronger for bloods collected post-fortification. Several nutrient/breast cancer associations varied across subgroups defined by age, smoking, alcohol, multivitamin use, and MTHFR status (p-interaction < 0.05). CONCLUSIONS: Overall, plasma B-vitamins and metabolites were not associated with lower breast cancer risk. Plasma vitamin B-12 was positively associated with higher risk of overall breast cancer, and plasma folate was positively associated with risk of invasive breast cancer. Additionally, there may be associations in subgroups defined by related genetic variants, breast cancer risk factors, and tumor factors. Further studies in younger women and in the post-fortification era are needed to confirm these findings.

Homocysteine Metabolism in Children and Adolescents: Influence of Age on Plasma Biomarkers and Correspondent Genotype Interactions.

BACKGROUND: Imbalance of homocysteine (Hcy) metabolism links with several pathologies; nevertheless, it is poorly characterized in pediatric populations. This study investigated the impact of age on plasma concentrations of Hcy and relevant biomarkers along with correspondent genotype interactions. METHODS: A healthy pediatric cohort aged 9 (n = 195) and 17 (n = 128) years old (yo) was studied. Immunoassays and GC-MS-SIM-mode quantified plasma levels of Hcy and biomarkers. PCR-RFLP or quantitative-PCR assays assessed common variations in related genes. RESULTS: Age impacted on levels of Hcy and metabolic markers: older children presented with the lowest folates and total-cobalamin (tCbl), while with the highest Hcy concentrations, whereas methylmalonic acid (MMA) and holotranscobalamin (Holo-TC) levels remained similar in 9-yo and 17-yo children. The relationships between B-vitamins and metabolic markers were also dependent on age. Only in the older children, MMA correlated with tCbl and Holo-TC, and MMA levels were markedly higher in the 17-yo subjects presenting with the lowest quartiles of Holo-TC concentrations. Lastly, age also impacted on the correlations between genotype and biomarkers. In the 17-yo group, however not in the 9-yo children, tHcy differed between MTHFR 677 genotypes, with subjects who had the MTHFR 677TT genotype displaying the highest tHcy concentrations. CONCLUSIONS: Age impacts on the Hcy metabolism dynamics in a pediatric population.

The U-shaped Relationship Between Serum Methylene Tetrahydrofolate Reductase and Large-artery Atherosclerotic Stroke.

BACKGROUND: Methylene tetrahydrofolate reductase (MTHFR) gene polymorphisms have been reported to be associated with ischemic stroke. However, the association between serum MTHFR level and ischemic stroke has not yet been studied. We aimed to examine the association between them in patients with large-artery atherosclerotic stroke and community-based healthy controls. METHODS: This study includes three hundred ninety-five patients with large-artery atherosclerotic stroke from the China Antihypertensive Trial in Acute Ischemic Stroke (CATIS) and 395 age- and sex-matched healthy controls from Chinese communities. Serum MTHFR concentrations were examined and some conventional risk factors of stroke were collected. The association between serum MTHFR and large-artery atherosclerotic stroke was evaluated. RESULTS: A U-shaped association of serum MTHFR level with large-artery atherosclerotic stroke was observed (p for nonlinearity =0.008). After multivariate adjustment, the odds ratios (95% confidence intervals) of large-artery atherosclerotic stroke associated with the first, second, fourth, and fifth quintiles of MTHFR were 5.62 (1.10-28.87), 2.13 (0.51-8.99), 1.08 (0.21-5.56), and 2.31 (0.57-9.34), respectively, compared with the third quintiles of MTHFR. Adding MTHFR quintiles to a model containing conventional risk factors improved the predictive power for large-artery atherosclerotic stroke (continuous net reclassification improvement=63.78%, p<0.001; categorical net reclassification improvement=2.54%, p=0.012). CONCLUSION: There is a significant U-shaped relationship between serum MTHFR levels and largeartery atherosclerotic stroke. Our findings raise the possibility that serum MTHFR may have a potential role in the pathogenesis of large-artery atherosclerotic stroke.

Investigation of potential biomarkers for thrombosis related diseases in Turkish Cypriot population.

Genetic and environmental factors are involved in development of many diseases. The allelic frequencies may differ in different populations and in different ethnic groups. The aim of this study was to investigate the genotypes of MTHFR and factor VII polymorphisms and to identify biomarkers for thrombosis related diseases in Turkish Cypriot population. The lipid profiles and genotypes of MTHFR polymorphisms (rs1801133, rs1801131) and factor VII (rs6046) genes were investigated for the first time in the Turkish Cypriot population. The heterozygosity for MTHFR (rs1801133, rs1801131) and FVII (rs6046) polymorphisms is high in Turkish Cypriot population. The heterozygosity for MTHFR C677T was 38%, MTHFR A1298C was 40% and factor VII G353A was 37%, respectively. Allelic frequencies between males and females were similar. There were no correlations between the genotypes of polymorphisms and the lipid profiles. This study is the first genetic epidemiology study that investigated the allelic frequencies of MTHFR and FVII polymorphisms associated with metabolic syndromes. This study proves to be a crucial analysis in order to use these polymorphisms as a predictor of disease development in the Turkish Cypriot community.

Impaired Homocysteine Metabolism Associated with High Plasma Interleukin-17A Levels, a Pro-Atherogenic Marker, in an Endogamous Population of North India.

Background: Impaired homocysteine metabolism (IHM; hyperhomocysteinemia) has been linked with many complex disorders like cardiovascular diseases and immunological disturbances. However, studies understanding IHM in light of pro- and anti- atherogeneic markers like Interleukin-17A & -10 (IL-17A & IL-10) and Forkhead box p3 (Foxp3, a master transcription factor) are scarce. Aim: In our present study, we aimed to understand the relation of IHM with plasma IL-17A and IL-10 levels and Foxp3 mRNA expression in peripheral blood mononuclear cells (PBMCs) from an endogamous population (Jats of Haryana, North India) with high prevalence of IHM without the concurrence of significant adverse cardiovascular outcomes. Methods: Forty (40) clinically healthy individuals, unrelated up to first cousins, were recruited and were subjected to demographic, physiological and anthropometric profiling, followed by intravenous blood sample collection (fasting) and lipid profiling. Plasma homocysteine levels were estimated and individuals with homocysteine levels ≥ 15umol/L and <15umol/L were categorized as the impaired homocysteine metabolism group (IHM, n=30) and normal homocysteine metabolism group (NHM, n=10) respectively. Plasma folate and vitamin B12 and MTHFR C677T (methylenetetrahydrofolate reductase) polymorphism were detected. Relative mRNA expression of Foxp3 in PBMCs (normalized to 18S) was quantitated using SyBR green technology. Plasma IL-10 & 17 levels were estimated by ELISA assays. Results and Conclusions: None of the physiological, anthropometric and lipid variables were different between the two groups. Foxp3 mRNA expression levels were relatively lower, and plasma IL-10 levels were found to be comparable among IHM and NHM group. However, significantly higher IL-17A levels and relatively high LDL cholesterol levels were present in the IHM group as compared with NHM. Our findings suggest that the Jats of Haryana, North India, exhibiting high levels of homocysteine, might also carry the high IL-17A -pro-atherogenic marker, suggesting an increasing burden of pre-morbid condition. This apparently does not reach to significant mortality/morbidity attributed to the counter action or balancing act of IL-10 (an anti-atherogenic marker). This further suggests environment-influenced epigenetic control mechanisms of the targeted genes in the present population.

Methylenetetrahydrofolate Reductase Deficiency Deregulates Regional Brain Amyloid-ß Protein Precursor Expression and Phosphorylation Levels.

Deregulation of the amyloid-ß protein precursor (AßPP) plays a critical role in the neurodegenerative cascade of Alzheimer's disease (AD). Significantly, common functional polymorphisms in the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene are a risk factor for the development of late-onset AD. Reduced MTHFR activity is associated with alterations in folate and homocysteine metabolism. Here, we first show that in young MTHFR knockout mice, mild and severe MTHFR deficiency markedly increase cortical and hippocampal AßPP phosphorylation at the regulatory Thr668 site. However, the hippocampus is especially vulnerable to the effects of aging and mild MTHFR deficiency. Notably, the effects of severe MTHFR deficiency in young mice are recapitulated by prolonged dietary folate deficiency in old mice, which leads to regional brain accumulation of cystathionine due to impaired methylation of homocysteine. The incremental AßPP phosphorylation at Thr668 mediated by severe genetic-or diet-induced impairment of the folate cycle correlates with enhanced accumulation of demethylated protein phosphatase 2A (PP2A), and activation of glycogen synthase kinase-3ß (GSK-3ß). Lastly, we show that severe disturbances in folate metabolism can also affect AßPP expression levels in a brain region specific manner. Together our findings identify a novel link between genetic MTHFR deficiency, activation of GSK-3ß, demethylation of PP2A, and enhanced phosphorylation of AßPP at Thr668, which is known to critically influence neuronal AßPP function and pathological amyloidogenic processing. Deregulation of AßPP provides a novel mechanism by which common human MTHFR polymorphisms may interact with dietary folate deficiency to alter neuronal homeostasis and increase the risk for sporadic AD.

Thrombophilic Gene Mutations in Relation to Different Manifestations of Venous Thromboembolism: A Single Tertiary Center Study.

BACKGROUND: Venous thromboembolism (VTE) is a common and potentially lethal disorder that manifests mainly as deep vein thrombosis (DVT) of the extremities or pulmonary embolism (PE) and occurs as a consequence of genetic and environmental risk factors. We aimed to assess the role of inherited thrombophilia as a causative or additive factor in the development of VTE. METHODS: The study included 310 patients (female: 154; mean age: 52.3 ± 16.9 years) with a first episode of VTE and 289 age- and sex-matched healthy controls. All participants underwent screening for thrombophilia-associated polymorphisms including factor V Leiden (FVL), prothrombin G20210A (PTG), factor V H1299 R (factor V HR2), factor XIII V34 L, ß-fibrinogen-455 G>A, plasminogen activator inhibitor-1 4G/5G, human platelet antigen-1 a/b, methylene tetrahydrofolate reductase (MTHFR) C677 T, MTHFR A1298C, angiotensin-converting enzyme I/D, apolipoprotein B R3500Q, and apolipoprotein E (Apo E). In addition, serum homocysteine (Hcy) levels were measured. RESULTS: In the patient group, 247 (80%) had isolated DVT, 43 (14%) had DVT plus PE, and 20 (6%) had isolated PE. The mean Hcy levels were similar in VTE subgroups and controls. Compared to controls, patients with isolated DVT, DVT plus PE, and isolated PE showed significantly higher frequencies for the following-heterozygous FVL mutation, isolated DVT (28.3%), DVT plus PE (44.2%), isolated PE (50%), controls (8.3%; P < .001); heterozygous PTG mutation, isolated DVT (11.3%), DVT plus PE (20.9%), isolated PE (25%), controls (5.9%; P < .01); Apo E 2/4, isolated DVT (9.7%), DVT plus PE (9.3%), isolated PE (5%), controls (1%; P < .01).The MTHFR A1298C mutation showed a significantly higher frequency in isolated patients with PE than in those with isolated DVT ( P = .006) and in controls ( P = .008). The frequencies of other genetic mutations or polymorphisms showed similar frequencies in all comparisons. In logistic regression analysis, heterozygous FVL mutation was the only independent predictor of VTE (odds ratio: 3.9, 95% confidence interval: 1.3-11.2; P = .012). CONCLUSION: Except than FVL, PTG, and Apo E 2/4 mutations, many of aforementioned thrombophilic factors known to be associated with VTE did not demonstrate any relationship with VTE. Heterozygous mutation of FVL was an independent predictor for VTE.

Superficial vein thrombosis in non-varicose veins of the lower limbs and thrombophilia.

Objectives Superficial vein thrombosis in non-varicose veins of the lower limbs is rather frequent and may be underestimated. This study aims to evaluate the prevalence of inherited or acquired thrombophilia in a sample of outpatients with the disease. Method An observational study was conducted on 73 consecutive superficial vein thrombosis patients tested for inherited or acquired thrombophilia. Results Sixty of 73 patients with superficial vein thrombosis completed the testing protocol, while 13 dropped out; 46 of 60 patients were found to have a thrombophilia (76.6%). The types detected were: factor V Leiden (31/60, i.e. 51.6%), prothrombin mutation (2/60, i.e. 3.3%), MTHFR mutation (23/60, i.e. 38.3%), antiphospholipid antibodies (5/60, i.e. 8.3%), protein C deficit (1/60, i.e. 1.6%), protein S deficit (1/60, i.e. 1.6%), and antithrombin deficit (0/60, i.e. 0%). Conclusions Among patients with superficial vein thrombosis in non-varicose veins, testing demonstrated a high prevalence of thrombophilia. The most common form proved to be factor V Leiden. As thrombophilia was found to be a major cause of superficial vein thrombosis in non-varicose veins, the authors recommend that patients with superficial vein thrombosis in non-varicose veins be investigated for thrombophilia.

Interplay between 3'-UTR polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene and the risk of ischemic stroke.

Stroke incidence is a multifactorial disease and especially hyperhomocysteinemia is associated with a higher risk of stroke. Previous studies have reported a folate metabolism disorder associated with the MTHFR gene. We investigated four single nucleotide polymorphisms in the MTHFR 3'-UTR [2572 C > A (rs4846049), 4869 C > G (rs1537514), 5488 C > T (rs3737967), and 6685 T > C (rs4846048)] to elucidate associations between ischemic stroke prevalence and prognosis. We examined 511 consecutive patients with ischemic stroke. Additionally, we selected 411 sex-/age-matched control subjects from patients presenting at our hospitals during the same period. The MTHFR 2572 C > A and 6685 T > C were significantly associated with ischemic stroke prevalence in the cardioembolism subgroup (MTHFR 2572CC vs. CA + AA: AOR, 2.145; 95% CI, 1.203-3.827; P = 0.010; MTHFR 6685TT vs. CC: AOR, 10.146; 95% CI, 1.297-79.336; P = 0.027). The gene-environment combined effect was significant, with MTHFR 2572CA + AA and folate levels ≤3.45 ng/mL correlating with ischemic stroke incidence. In addition, the total homocysteine (tHcy) levels in subjects with MTHFR 2572AA were elevated compared to tHcy levels in subjects with MTHFR 2572CC. Therefore, we suggest that MTHFR 2572 C > A and 6685 T > C are associated with ischemic stroke pathogenesis. The combined effects of the MTHFR 3'-UTR polymorphisms and tHcy/folate levels may contribute to stroke prevalence.

Hypermethylated CpG sites in the MTR gene promoter in preterm placenta.

AIM: Altered maternal one-carbon metabolism influences placental DNA methylation patterns and 'programs' the fetus for noncommunicable diseases in adult life. EXPERIMENTAL PROCEDURES: Levels of plasma folate, vitamin B12, homocysteine, mRNA and protein levels of MTHFR and MTR enzymes in placenta were compared among women delivering preterm (n = 83) and term (n = 75). MTR promoter CpG methylation was undertaken. RESULTS: MTHFR and MTR mRNA levels were higher while protein levels were lower, and MTR CpG sites were hypermethylated in the preterm group, as compared with the term group. Methylated CpG sites were negatively associated with maternal plasma vitamin B12 levels. CONCLUSION: Study suggests a dysregulation of enzyme genes in remethylation arm of the one-carbon metabolism in placenta of women delivering preterm.

Lethal hepatotoxicity following 5-fluorouracil/cisplatin chemotherapy: a relevant case report.

Some articles have reported severe toxicities induced by cisplatin/5-fluorouracil regimens, nevertheless, severe and lethal liver toxicity has not been previously reported. In this article, we report the case of a 72-year-old woman, who developed fulminant hepatitis, hypoglycemia and hypotension with atrial fibrillation not responding to treatment. After ruling out all other possible causes of hepatitis, the toxicity was more likely attributed to 5-fluorouracil. Genotyping was performed and the patient was found to be a homozygote carrier of the T variant of the MTHFR gene. The patient died two days later. Several factors, including genetic factors, could explain this severe toxicity. The present case discusses the importance of personalized medicine in oncology based on pharmacogenetic analysis of polymorphisms.

The impact of MTHFR 677 C/T genotypes on folate status markers: a meta-analysis of folic acid intervention studies.

PURPOSE: Methylenetetrahydrofolate reductase (MTHFR) is a key folate pathway enzyme with the T variant of the MTHFR gene increasing the risk of low folate status, particularly coupled with low folate intake. As genetic variability of MTHFR influences folate status, it is important to ensure an adequate intake that overrides genetic effects but minimises any adverse effects. Our aim was to assess the influence of MTHFR genotype on folate status followed by response to supplementation. METHODS: We performed a meta-analysis of ten folate intervention studies to assess the degree to which MTHFR C677T genotype influenced plasma homocysteine and serum folate levels as measures of folate status. We then examined response after supplementation at intake values up to the upper tolerable limit. RESULTS: The MTHFR 677TT genotype was associated with higher plasma homocysteine (2.7 µmol/L, TT vs. CT/CC; 2.8 µmol/L, TT vs. CC) and lower serum folate (2.5 nmol/L, TT vs. CT/CC; 3.6 nmol/L, TT vs. CC). In two studies, the TT groups had mean plasma Hcy >15 µmol/L. Serum folate levels were >7 nmol/L for all genotype groups. After supplementation of 400 up to 1670 µg DFEs of folic acid or folic acid + fortified foods and/or natural food folates for a minimum of 4 weeks, there were no significant differences in plasma homocysteine levels; however, individuals with the TT genotype had a lower serum folate response to supplementation (7.2 nmol/L, TT vs. CT/CC; 8.7 nmol/L, TT vs. CC). CONCLUSIONS: This meta-analysis confirms observations from observational and intervention studies that MTHFR TT genotype is associated with increased plasma homocysteine and lowered serum folate and less response to short-term supplementation. The results can be used for modelling and guiding personalised intake recommendations for the nutrient folate.

One-carbon metabolites and telomere length in a prospective and randomized study of B- and/or D-vitamin supplementation.

BACKGROUND: Vitamin B deficiency is common in elderly people and has been associated with an increased risk of developing age-related diseases. B-vitamins are essential for the synthesis and stability of DNA. Telomers are the end caps of chromosomes that shorten progressively with age, and short telomers are associated with DNA instability. OBJECTIVE: In the present randomized intervention study, we investigated whether the one-carbon metabolism is related to telomere length, a surrogate marker for cellular aging. DESIGN: Sixty-five subjects (>54 years) were randomly assigned to receive either a daily combination of vitamin D3 (1200 IU), folic acid (0.5 mg), vitamin B12 (0.5 mg), vitamin B6 (50 mg) and calcium carbonate (456 mg) (group A) or vitamin D3 and calcium carbonate alone (group B). Blood testing was performed at baseline and after 1 year of supplementation. The concentrations of several metabolites of the one-carbon pathway, as well as relative telomere length (RTL) and 5,10-methylenetetrahydrofolate reductase C677T genotype, were analyzed. RESULTS: At baseline, age- and gender-adjusted RTL correlated with total folate and 5-methyltetrahydrofolate (5-methylTHF). Subjects with RTL above the median had higher concentrations of total folate and 5-methylTHF compared to subjects below the median. At study end, gender- and age-adjusted RTL correlated in group A with methylmalonic acid (MMA; r = -0.460, p = 0.0012) and choline (r = 0.434, p = 0.0021) and in group B with 5,10-methenyltetrahydrofolate (r = 0.455, p = 0.026) and dimethylglycine (DMG; r = -0.386, p = 0.047). Subjects in the group A with RTL above the median had lower MMA and higher choline compared to subjects below the median. CONCLUSIONS: The present pilot study suggests a functional relationship between one-carbon metabolism and telomere length. This conclusion is supported by several correlations that were modified by B-vitamin supplementation. In agreement with our hypothesis, the availability of nucleotides and methylation groups seems to impact telomere length. Due to the small sample size and the limitations of the study, further studies should confirm the present results in a larger cohort.