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Hyperhomocysteinemia
Selected AbstractsHyperhomocysteinemia in epileptic patients on new antiepileptic drugsEPILEPSIA, Issue 2 2010Vincenzo Belcastro Summary Purpose:, Older enzyme-inducing antiepileptic drugs (AEDs) may induce supraphysiologic plasma concentrations of total (t) homocysteine (Hcy). The aim of the present study was to investigate the effect of new AEDs on plasma tHcy levels. Methods:, Patients 18,50 years of age, on AEDs monotherapy, with no other known cause of hyper-tHcy were enrolled. Plasma tHcy, folate, vitamin B12, and AEDs levels were determined by standard high-performance liquid chromatography (HPLC) methods. Methylenetetrahydrofolate-reductase (MTHFR) polymorphisms were checked using Puregene genomic DNA purification system (Gentra, Celbio, Italy). A group of healthy volunteers matched for age and sex was taken as control. Results:, Two hundred fifty-nine patients (151 on newer and 108 on older AEDs) and 231 controls were enrolled. Plasma tHcy levels were significantly higher [mean values, standard error (SE) 16.8, 0.4 vs. 9.1, 0.2 ,m; physiologic range 5,13 ,m] and folate lower (6.3, 0.1 vs. 9.3, 0.1 nm; normal > 6.8 nm) in patients compared to controls. Patients treated with oxcarbazepine, topiramate, carbamazepine, and phenobarbital exhibited mean plasma tHcy levels above the physiologic range [mean values (SE) 16 (0.8), 19.1 (0.8), 20.5 (1.0), and 18.5 (1.5) ,m, respectively]. Conversely, normal tHcy concentrations were observed in the lamotrigine and levetiracetam groups [both 11.1 (0.5) ,m]. Discussion:, Oxcarbazepine and topiramate might cause hyper-tHcy, most likely because of the capacity of these agents to induce the hepatic enzymes. Because literature data suggest that hyper-tHcy may contribute to the development of cerebrovascular diseases and brain atrophy, a supplement of folate can be considered in these patients to normalize plasma tHcy. [source] Hyperhomocysteinemia in Children Treated with Antiepileptic Drugs Is Normalized by Folic Acid SupplementationEPILEPSIA, Issue 10 2005Martina Huemer Summary:,Purpose: To assess the prevalence of hyperhomocysteinemia in pediatric patients treated with antiepileptic drugs (AEDs) and to evaluate the effect of folic acid supplementation on plasma total homocysteine (tHcy) concentrations in hyperhomocysteinemic patients. Methods: 123 patients from three regional hospitals participated in the study. Patients with hyperhomocysteinemia were included in a 3-month double-blind randomized trial testing oral folic acid supplementation (1 mg/day) versus placebo. Results: Hyperhomocysteinemia (tHcy >10.4 ,mol/L) was present in 19 of 123 patients. Patients with hyperhomocysteinemia were older (13.7 ± 4 vs. 11.0 ± 3.9 years) and had significantly lower folate and cobalamin concentrations. Multidrug (two or more) AED treatment and duration of therapy correlated significantly with elevated total homocysteine (tHcy) and low folate. In contrast, polymorphisms in the methylene tetrahydrofolate reductase gene (MTHFR 677 C,T, 1298 A,C, 1793 G,A) had no significant impact on tHcy. Nine of 19 patients with hyperhomocysteinemia were randomized to placebo, whereas the remaining 10 patients received folic acid supplementation. Folic acid supplementation resulted in a significant increase of folate and decrease of tHcy, whereas both parameters remained unchanged in the placebo group. Conclusions: Hyperhomocysteinemia is present in 15.5% of children receiving long-term AED treatment. Multidrug treatment and long duration of therapy enhance the risk for hyperhomocysteinemia. Folic acid supplementation significantly reduces tHcy. We recommend assessment of serum folate and plasma tHcy in children receiving AEDs. [source] Protective Effect of Vitamin E Against Ethanol-Induced Hyperhomocysteinemia, DNA Damage, and Atrophy in the Developing Male Rat BrainALCOHOLISM, Issue 7 2009Alireza Shirpoor Background:, Chronic alcoholism leads to elevated plasma and brain homocysteine (Hcy) levels, as demonstrated by clinical investigations and animal experiments. It has been posited that elevated levels of Hcy mediate DNA damage, brain atrophy, and excitotoxicity. The current study sought to elucidate the effect of vitamin E on ethanol-induced hyperhomocysteinemia, DNA damage, and atrophy in the developing hippocampus and cerebellum of rats. Methods:, Pregnant Wistar rats received ethanol with or without vitamin E from gestation day 7 throughout lactation. Weight changes in the brain, hippocampus and cerebellum, DNA damage, and Hcy levels in the plasma, hippocampus, and cerebellum of male offspring were measured at the end of lactation. Results:, The results revealed that along with a significant decrease in brain, cerebellum, and hippocampus weights in animals that received alcohol, the levels of DNA damage and Hcy significantly increased. Significant amelioration of brain atrophy and DNA damage as well as restoration of the elevated level of Hcy to that of controls were found in vitamin E-treated rats. Conclusions:, These findings strongly support the idea that ethanol intake by dams during pregnancy and lactation induces Hcy-mediated oxidative stress in the developing hippocampus and cerebellum of offspring rats, and that these effects can be alleviated by vitamin E as an antioxidant. [source] Hyperhomocysteinemia and low B vitamin levels are independently associated with venous thromboembolism: results from the EDITH study: a hospital-based case,control studyJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 4 2006E. OGER Summary.,Background:,Moderate hyperhomocysteinemia and B vitamins deficiency are thought to be risk factors for venous thromboembolism (VTE). The causality and independence of those associations are still questioned. Methods:,We measured fasting serum total homocysteine, folates, and vitamin B12 levels as well as 5,10-methylenetetrahydrofolate reductase (MTHFR) C677T genotypes in 467 patients hospitalized with a first well-documented deep vein thrombosis and/or pulmonary embolism not related to a major acquired risk factor and 467 controls matched for gender and age. Results:,Mild hyperhomocysteinemia, low serum folates, and vitamin B12 were associated with VTE independently of each other. In multivariate analysis, odds ratios (OR) (95% CI) for VTE associated with mild hyperhomocysteinemia (>15 ,mol L,1), low serum folates (,,4.9 nmol L,1), and vitamin B12 (, 253 pmol L,1) were 1.48 (1.05,2.08), 3.14 (1.35,7.32) and 1.42 (1.03,1.98), respectively. An MTHFRC677T genotype was not significantly associated with VTE; OR (95% CI): 1.13 (0.70,1.81) Conclusions:,The current data provides further knowledge in the complex relationship between hyperhomocysteinemia, low vitamin levels, and VTE. [source] The 894 G > T variant of endothelial nitric oxide synthase (eNOS) increases the risk of recurrent venous thrombosis through interaction with elevated homocysteine levelsJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 5 2004S. G. Heil Summary.,Background: Venous thrombosis is a multicausal disease involving both genetic as well as acquired risk factors. Hyperhomocysteinemia is associated with a 2-fold increased risk of recurrent venous thrombosis (RVT). Recently, the 894 G > T variant of endothelial nitric oxide synthase (eNOS) was postulated to be associated with hyperhomocysteinemia. Objectives: We hypothesized an interrelation of hyperhomocysteinemia, the eNOS 894 G > T variant and RVT risk. Methods: The eNOS 894 G > T variant was studied in 170 cases with a history of RVT and 433 controls from the general population. Results: The eNOS 894 TT genotype may increase RVT risk [odds ratio (OR) 1.3 (0.7,2.6)], but no association of the eNOS 894 G > T variant with elevated homocysteine was found in controls. Interestingly, in RVT cases the coexistence of both the 894 TT genotype and elevated tHcy levels (> 90th percentile) was more frequently present than in controls, which led to a substantially increased risk of recurrent venous thrombosis [fasting tHcy OR 5.3 (1.1,24.1), postload tHcy OR 6.5 (1.6,29.5)]. Conclusion: The results of the present study demonstrate that the eNOS 894 G > T variation interacts with elevated tHcy levels, leading to an increased risk of recurrent thrombotic events. This interaction points in the direction of S-nitrosation as a mechanism by which homocysteine exerts its detrimental effects on the hemostatic system. [source] G1793A polymorphisms in the methyl- enetetrahydrofolate gene: Effect of folic acid on homocysteine levelsMOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 8 2006Sandra Soares Melo Abstract Mutations or polymorphisms in the gene of the enzyme methylenetetrahydrofolate (MTHFR) are associated with hyperhomocysteinemia and possibly with an elevated risk for vascular diseases. A study was conducted on 83 individuals with type 2 diabetes in order to determine the allelic and genotypic frequencies of the G1793A mutation and to assess the effect of folic acid supplementation on plasma homocysteine concentrations. The patients were attended by the Diabetes and Hypertension Program , Balneario Camboriu/SC and received daily supplements containing 1 mg of folic acid for 3 months. DNA was previously extracted from leukocytes and the G1793A mutation was detected by PCR-RFLP. Blood samples were collected during the basal period and after supplementation for the determination of homocysteine by HPLC, and of folic acid and vitamin B12 by RIA. The allele frequency for the G1793A mutation was 3.01% and no homozygous individuals with mutant alleles were detected. Hyperhomocysteinemia was diagnosed in 27.71% of the patients, folic acid deficiency in 15.66%, and vitamin B12 deficiency in 7.23%. Plasma homocysteine concentrations were inversely correlated with folic acid (r = ,0.27, p = 0.01) and vitamin B12 (r = ,0.21; p = 0.05) concentrations. The individuals with a heterozygous genotype for the G1793A mutation showed borderlines or deficient values in folic acid and vitamin B12 concentrations compared to individuals with a normal genotype. Hyperhomocysteinemia and the vitamin deficiencies presented by type 2 diabetic individuals, included with a heterozygous genotype for the G1793A mutation in the MTHFR gene, reached normal values by daily folic acid supplementation. [source] Hyperhomocysteinemia in pediatric and young adult renal transplant recipientsPEDIATRIC TRANSPLANTATION, Issue 2 2004Amir Belson Abstract:, Hyperhomocysteinemia (HHcy) has been recently identified as an important and reversible cardiovascular risk factor in adult and pediatric renal transplant recipients. A retrospective cross-sectional analysis of 70 pediatric and young adult renal transplant recipients was performed to determine the prevalence, and important clinical and laboratory correlates of HHcy. Total homocysteine concentration, free and protein bound, was determined by fluorescence polarization immunoassay using an IMX analyzer. Hyperhomocysteinemia was defined as a serum homocysteine (Hcy) level above the 95th percentile for age. Fifty-four of 70 patients (77%) had HHcy. Comparison of patients with HHcy with patients without HHcy demonstrated no statistical difference in age (p = 0.35), gender (p = 0.76) or donor type (p = 0.20). Patients with HHcy had significantly lower calculated creatinine clearance values (Ccr) (p = 0.02), 67.3 ± 21.2 mL/min/1.73 m2 vs. 90.7 ± 32.3 mL/min/1.73 m2 for patients without HHcy. Immunosuppression did not correlate with the diagnosis of HHcy. Stepwise logistic regression identified patient age (0.18, p = 0.013) and Ccr (,0.04, p = 0.011) as significant variables. In conclusion, HHcy is more common than expected in pediatric renal transplant recipients. Patients with Ccr <80 mL/min/1.73 m2 were statistically more likely to have a diagnosis of HHcy. We recommend that Hcy levels should be evaluated in this high risk population. [source] Homocysteine, white matter hyperintensities, and cognition in healthy elderly peopleANNALS OF NEUROLOGY, Issue 2 2003Carole Dufouil PhD Hyperhomocysteinemia is associated with an increased risk of vascular disease, and recent results suggest that it also could increase the risk of dementia. We examined the relationship between homocysteine and cognitive decline in 1,241 subjects aged 61 to 73 years, followed up over 4 years. Plasma homocysteine levels were determined in all participants as well as cardiovascular risk factors, apolipoprotein E genotype, plasma levels of folate, and vitamin B12. Cognitive performances were assessed repeatedly by using Mini-Mental State Examination, Trail Making Test, Digit Symbol Substitution Test, and Finger Tapping Test. At 2-year follow-up, 841 subjects underwent cerebral magnetic resonance imaging, and white matter hyperintensities were rated visually. Analyses were adjusted for all cardiovascular risk factors. Cross-sectional analyses showed that higher concentrations of homocysteine were significantly related to poorer performances at all neuropsychological tests. Longitudinal analyses confirmed this finding. The odds of cognitive decline was 2.8-fold (p < 0.05) higher in subjects with homocysteine levels above 15,mol/L compared with those with homocysteine levels below 10,mol/L. In participants who underwent magnetic resonance imaging, the relationship between homocysteine and cognition was unchanged after taking into account white matter hyperintensities suggesting that white matter hyperintensities do not mediate the association between homocysteine and cognition. Ann Neurol 2003;53:000,000 [source] Methylenetetrahydrofolate reductase gene polymorphisms in patients with nonalcoholic steatohepatitis (NASH)CELL BIOCHEMISTRY AND FUNCTION, Issue 3 2008Ali Sazci Abstract Nonalcoholic fatty liver disease (NAFLD) is the most common cause of abnormal hepatic steatosis in the absence of a history of alcohol use. Nonalcoholic steatohepatitis (NASH) is the progressive form of NAFLD. Hyperhomocysteinemia causes steatosis, and the methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C polymorphisms result in hyperhomocysteinemia. To examine whether the C677T and A1298C polymorphisms of the MTHFR gene were associated with NASH, we analysed the allele and genotype distribution of the MTHFR C677T and A1298C polymorphisms in 57 well-diagnosed NASH patients, 324 healthy controls in a case-control study of Turkish subjects of Caucasian origin. The diagnosis of the NASH patients was based on liver biopsy. The method used in the analysis of genotypes was PCR-RFLP. The MTHFR A1298C polymorphism was significantly associated with NASH (,2,=,8.439; p,=,0.015) in the total NASH patients compared with healthy controls. The MTHFR 1298C allele (odds ratio (OR),=,2.480; 95%CI,=,1.286,4.782; ,2,=,7.703; df,=,1; p,=,0.006) was significantly associated with NASH in the total NASH patients. The MTHFR C677C/A1298C compound genotype (OR,=,2.218; 95%CI,=,1.003,4.906; ,2,=,3.998; df,=,1; p,=,0.046) in men patients was also significantly associated with NASH. Likewise the MTHFR C1298C genotype was significantly associated with NASH in women patients with NASH (OR,=,2.979; 95%CI,=,1.027,8.641; ,2,=,4.343; df,=,1; p,=,0.037). In conclusion, the MTHFR 1298C allele in all NASH patients, C1298C genotype, C677C/C1298C compound genotype in women NASH patients and C677C/A1298C compound genotype in men NASH patients were genetic risk factors for NASH. Copyright © 2007 John Wiley & Sons, Ltd. [source] Hyperhomocysteinemia in Children Treated with Antiepileptic Drugs Is Normalized by Folic Acid SupplementationEPILEPSIA, Issue 10 2005Martina Huemer Summary:,Purpose: To assess the prevalence of hyperhomocysteinemia in pediatric patients treated with antiepileptic drugs (AEDs) and to evaluate the effect of folic acid supplementation on plasma total homocysteine (tHcy) concentrations in hyperhomocysteinemic patients. Methods: 123 patients from three regional hospitals participated in the study. Patients with hyperhomocysteinemia were included in a 3-month double-blind randomized trial testing oral folic acid supplementation (1 mg/day) versus placebo. Results: Hyperhomocysteinemia (tHcy >10.4 ,mol/L) was present in 19 of 123 patients. Patients with hyperhomocysteinemia were older (13.7 ± 4 vs. 11.0 ± 3.9 years) and had significantly lower folate and cobalamin concentrations. Multidrug (two or more) AED treatment and duration of therapy correlated significantly with elevated total homocysteine (tHcy) and low folate. In contrast, polymorphisms in the methylene tetrahydrofolate reductase gene (MTHFR 677 C,T, 1298 A,C, 1793 G,A) had no significant impact on tHcy. Nine of 19 patients with hyperhomocysteinemia were randomized to placebo, whereas the remaining 10 patients received folic acid supplementation. Folic acid supplementation resulted in a significant increase of folate and decrease of tHcy, whereas both parameters remained unchanged in the placebo group. Conclusions: Hyperhomocysteinemia is present in 15.5% of children receiving long-term AED treatment. Multidrug treatment and long duration of therapy enhance the risk for hyperhomocysteinemia. Folic acid supplementation significantly reduces tHcy. We recommend assessment of serum folate and plasma tHcy in children receiving AEDs. [source] Mutated 5,10-methylenetetrahydrofolate reductase, hyperhomocysteinemia and risk for cardiovascular disease.EUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 1 2001Nature, nurture or nonsense? No abstract is available for this article. [source] BRIEF REPORT: Association between MTHFR 677C-T polymorphism and alcohol dependence according to Lesch and Babor typologyADDICTION BIOLOGY, Issue 4 2009Amine Benyamina ABSTRACT Prior studies have associated 677C-T Methylenetetrahydrofolate reductase (MTHFR) gene polymorphism with decreased enzymatic activity and modified homocysteine regulation. This study determines and compares MTHFR 677C-T distribution and examines its consequences on homocysteine metabolism and alcohol dependence in alcoholic patients classified according to the Babor and Lesch typologies. MTHFR TT genotype was more prevalent in AD patients with milder alcohol dependence (Babor type A) and with Lesch type 3, associated with depression. MTHFR TT was also associated with hyperhomocysteinemia. Determining MTHFR 677C-T genotype, folate and vitamin B12 levels could assist physicians in identifying type 3 patients and improve addictions management. [source] Transient global amnesia-like episode in a patient with severe hyperhomocysteinemiaEUROPEAN JOURNAL OF NEUROLOGY, Issue 9 2007A. Semmler No abstract is available for this article. [source] Plasma total homocysteine levels are associated with advanced leukoaraiosis but not with asymptomatic microbleeds on T2*-weighted MRI in patients with strokeEUROPEAN JOURNAL OF NEUROLOGY, Issue 3 2006H. Naka Both leukoaraiosis and asymptomatic microbleeds are associated with small-artery diseases. Although an association between hyperhomocysteinemia and leukoaraiosis has been reported, no studies have evaluated the association between total homocysteine (tHcy) level and presence of microbleeds in stroke patients. We evaluated the association between tHcy level and leukoaraiosis or microbleeds in stroke patients. In 102 patients with stroke (69.5 ± 10.3 years old, 54 men and 48 women), microbleeds on T2*-weighted MR images were counted, leukoaraiosis on T2-weighted images was graded and fasting plasma tHcy concentrations were measured. Plasma tHcy level was significantly higher in patients with advanced leukoaraiosis than in those without advanced leukoaraiosis (13.9 ± 4.6 ,mol/l vs. 10.2 ± 3.4 ,mol/l, P < 0.0001). Plasma tHcy level was not significantly different in patients with microbleeds and those without microbleeds (11.3 ± 4.1 ,mol/l vs. 11.4 ± 4.3 ,mol/l, P = 0.9441). Elevated tHcy level is significantly and independently associated with advanced leukoaraiosis [odds ratio (OR), 1.330; 95% CI, 1.130,1.565] but not with the presence of microbleeds. Elevated tHcy level appears to be associated with ischemic small-artery disease rather than with bleeding-prone small-artery disease. [source] Homocysteine-induced decrease in endothelin-1 production is initiated at the extracellular level and involves oxidative productsFEBS JOURNAL, Issue 20 2001Séverine Drunat The increased cardiovascular risk associated with hyperhomocysteinemia has been partly related to homocysteine (Hcy)-induced endothelial cell dysfunction. However, the intra or extracellular starting point of the interaction between Hcy and endothelial cells, leading to cellular dysfunction, has not yet been identified. We investigated the effects of both intracellular and extracellular Hcy accumulation on endothelin-1 (ET-1) synthesis by cultured human endothelial cells. Incubation of cultures with methionine (1.0 mmol·L,1) for 2 h induced a slight increase in cellular Hcy content but no change in ET-1 production. Incubation of cells with Hcy (0.2 mmol·L,1) led to a significant fall in ET-1 generation, accompanied by a significant increase in cellular Hcy content. Addition of the amino-acid transport system L substrate 2-amino-2-norbornane carboxylic acid had no effect on the Hcy-induced decrease in ET-1 production but significantly inhibited the Hcy-induced increase in the cellular Hcy content. Incubation of cells with a lower Hcy concentration (0.05 mmol·L,1) also reduced ET-1 production without increasing the cellular Hcy content. Co-incubation with extracellular free-radical inhibitors (superoxide dismutase, catalase and mannitol) markedly reduced the effect of Hcy on ET-1 production. Thus, it is extracellular Hcy accumulation that triggers the decrease in ET-1 production by endothelial cells through oxidative products. [source] Uremic hyperhomocysteinemia: A randomized trial of folate treatment for the prevention of cardiovascular eventsHEMODIALYSIS INTERNATIONAL, Issue 2 2007Areuza C. A. VIANNA Abstract Homocysteine is a risk factor for atherosclerosis in the general population, and serum homocysteine levels are almost universally elevated in chronic renal failure patients. When such patients are treated with dialysis, cardiovascular disease accounts for more than 50% of their mortality, which, in some proportion, may be pathophysiologically related to the elevated serum homocysteine levels. From April 2003 to March 2005, we conducted a 2-year, double-blind, randomized, placebo-controlled trial of 186 patients with end-stage kidney disease due to any cause, who were older than 18 years and stable on hemodialysis. Patients were assigned to receive either oral folic acid 10 mg 3 times a week immediately after every dialysis session under nurse supervision or an identical-appearing placebo for the entire study. On admission, plasma total homocysteine (tHcy) levels were above 13.9 ,mol/L in 96.7% of patients (median 25.0 ,mol/L, range 9.3,104.0 ,mol/L). In the placebo group, tHcy levels remained elevated at 6, 12, and 24 months, while oral folate significantly decreased tHcy to a median value of 10.5 (2.8,20.3) ,mol/L, (p<0.01). During the study, 38 patients (folic acid group 17 vs. placebo group 21; p=0.47) died from cardiovascular disease. Kaplan,Meier life table analysis dealing with the incidence of cardiovascular events, both fatal and nonfatal (myocardial infarction, arrhythmias, angina, heart failure, cerebrovascular accident), showed that 2 years of folic acid treatment and the lowering of the homocysteine blood levels had no effect on cardiovascular events (p=0.41; hazard ratio 1.24, 95% CI 0.74,2.10). However, the carotid artery intima-media wall thickness measured in a blinded fashion decreased from 1.94 ± 0.59 mm to 1.67 ± 0.38 mm (p<0.01) after 2 years of folate therapy. In this short-term study of uremic patients, 2 years of folic acid supplementation normalized the tHcy blood levels in 92.3% of patients but did not change the incidence of cardiovascular events compared with the control group. However, ultrasonography of the common carotid arteries performed at entry and 24 months later showed a significant decrease in intima-media thickness with folate supplementation. This suggests that early folate supplementation may benefit patients with chronic renal failure by preventing cardiovascular deterioration. [source] Inhibition of adiponectin production by homocysteine: A potential mechanism for alcoholic liver disease,HEPATOLOGY, Issue 3 2008Zhenyuan Song Although recent evidence suggests that down-regulation of production of the adipocyte hormone adiponectin has pathophysiological consequences for the development of alcoholic liver disease (ALD), the underlying mechanisms are elusive. Abnormal hepatic methionine-homocysteine metabolism induced by prolonged alcohol exposure has been reported both in clinical and experimental studies of ALD. Here, we conducted both in vivo and in vitro experiments to examine the effects of prolonged alcohol exposure on homocysteine levels in adipose tissue, its potential involvement in regulating adiponectin production, and the consequences for ALD. Chronic alcohol exposure decreased the circulating adiponectin concentration and adiponectin messenger RNA (mRNA) and protein levels in epididymal fat pads. Alcohol feeding induced modest hyperhomocysteinemia and increased homocysteine levels in the epididymal fat pad, which was associated with decreased mRNA levels of cystationine ,-synthase. Betaine supplementation (1.5%, wt/vol) in the alcohol-fed mice reduced homocysteine accumulation in adipose tissue and improved adiponectin levels. Moreover, exogenous homocysteine administration reduced gene expression, protein levels, and secretion of adiponectin in primary adipocytes. Furthermore, rats fed a high-methionine diet (2%, wt/wt) were hyperhomocysteinemic and had decreased adiponectin levels in both plasma and adipose tissue, which was associated with suppressed AMP-activated protein kinase activation in the liver. Mechanistic studies revealed that both inactivation of the extracellular signal regulated kinase 1/2 pathway and induction of endoplasmic reticulum stress response, specifically C/EBP homologous protein expression, may contribute to the inhibitory effect exerted by homocysteine. Conclusion: Chronic alcohol feeding caused abnormal accumulation of homocysteine in adipocytes, which contributes to decreased adiponectin production in ALD. (HEPATOLOGY 2008.) [source] Association of hyperhomocysteinemia and folate deficiency with colon tumors in patients with inflammatory bowel diseaseINFLAMMATORY BOWEL DISEASES, Issue 2 2008Jean Marc Phelip Abstract Background: Folate deficiency associated with hyperhomocysteinemia might increase the risk of developing colorectal cancer. The aim of this study was to evaluate factors associated with colonic carcinogenesis, in particular, folate and homocysteinemia levels, in a cross-sectional study of patients with inflammatory bowel disease (IBD). Methods: IBD patients with carcinogenic lesions discovered during colonoscopy [dysplasia-associated lesion or masses (DALM), colorectal cancer] were included and compared with the whole population of IBD patients with a normal colonoscopy performed during the same period. The following parameters were collected at the time of colonoscopy: age, sex, type, duration, activity, and extent of the disease, treatment, smoking status, and vitamin B12, folate, and homocysteinemia levels. Univariate and multivariate analyses were performed after adjusting for the main parameters. Results: One hundred and fourteen patients [41 with ulcerative colitis (UC), 73 with Crohn's disease (CD)] were included. Twenty-six carcinogenic lesions were isolated: 18 DALM (7 high-grade and 11 low-grade dysplasia) and 8 colorectal cancers. In univariate analysis, the factors associated with carcinogenesis were: active smoking (P = 0.03), folate level < 145 pmol/L (P = 0.02), hyperhomocysteinemia > 15 ,mol/L (P = 0.003), duration of disease > 10 years (P = 0.006), and UC (P = 0.02). In multivariate analysis, patients with hyperhomocysteinemia associated with folate deficiency had 17 times as many carcinogenic lesions as patients with normal homocysteinemia whatever the folate status and duration of the disease (P = 0.01). Patients with hyperhomocysteinemia without folate deficiency had 2.5 times as many carcinogenic lesions as patients with normal homocysteinemia (P = 0.08). Conclusions: Our data suggest that in IBD patients with normal homocysteinemia, the increase in carcinogenic risk is negligible. Conversely, in patients with hyperhomocysteinemia, folate deficiency may be associated with increased colorectal carcinogenesis in IBD patients. (Inflamm Bowel Dis 2007) [source] Livedoid vasculopathy and hypercoagulability in a patient with primary Sjögren's syndromeINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 4 2007Raquel Cardoso MD Background, A 31-year-old woman presented with a 5-year history of painful ulcerations, palpable purpura, porcelain-white atrophic scars of the malleolar region and dorsal aspect of the feet, livedo reticularis on the limbs, arthralgia, xerophthalmia, and xerostomia. Methods, Skin biopsy revealed vessel wall hyalinization and thrombosis of the microvasculature with a very scarce dermal inflammatory infiltrate. Biopsy of the oral mucosa showed mononuclear infiltration of an intralobular duct of a salivary gland. Results, Laboratory studies, including autoantibodies and inflammation markers, were normal, except for a positive rheumatoid factor. Coagulation screening revealed C677T methylenetetrahydrofolate reductase (MTHFR) mutation, with a normal serum homocysteine. The patient was treated with oral methylprednisolone (32 mg/day with progressive reduction) and enoxaparin (20 mg/day subcutaneously), with complete ulcer healing within 4 months. Conclusion, Livedoid vasculitis or vasculopathy has not been referred to previously in association with Sjögren's syndrome, but may be associated with other autoimmune disorders and anomalies of coagulation, namely factor V Leiden mutation, protein C deficiency, and MTHFR mutation, associated or not with hyperhomocysteinemia, a condition that seems to confer an increased risk of recurrent arterial and venous thrombosis. We stress the importance of anticoagulant therapy for ulcer healing and for the prevention of other thrombotic events. [source] Vascular Dementia: Distinguishing Characteristics, Treatment, and PreventionJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 5s2 2003Gustavo C. Román MD Vascular dementia (VaD) is the second-most-common cause of dementia in the elderly, after Alzheimer's disease (AD). VaD is defined as loss of cognitive function resulting from ischemic, hypoperfusive, or hemorrhagic brain lesions due to cerebrovascular disease or cardiovascular pathology. Diagnosis requires the following criteria: cognitive loss, often predominantly subcortical; vascular brain lesions demonstrated by imaging; a temporal link between stroke and dementia; and exclusion of other causes of dementia. Poststroke VaD may be caused by large-vessel disease with multiple strokes (multiinfarct dementia) or by a single stroke (strategic stroke VaD). A common form is subcortical ischemic VaD caused by small-vessel occlusions with multiple lacunas and by hypoperfusive lesions resulting from stenosis of medullary arterioles, as in Binswanger's disease. Unlike with AD, in VaD, executive dysfunction is commonly seen, but memory impairment is mild or may not even be present. The cholinesterase inhibitors used for AD are also useful in VaD. Prevention strategies should focus on reduction of stroke and cardiovascular disease, with attention to control of risk factors such as hypertension, diabetes mellitus, hypercholesterolemia, and hyperhomocysteinemia. [source] Nitrotyrosinylation, remodeling and endothelial-myocyte uncoupling in iNOS, cystathionine beta synthase (CBS) knockouts and iNOS/CBS double knockout miceJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 1 2009Soumi Kundu Abstract Increased levels of homocysteine (Hcy), recognized as hyperhomocysteinemia (HHcy), were associated with cardiovascular diseases. There was controversy regarding the detrimental versus cardio protective role of inducible nitric oxide synthase (iNOS) in ischemic heart disease. The aim of this study was to test the hypothesis that the Hcy generated nitrotyrosine by inducing the endothelial nitric oxide synthase, causing endothelial-myocyte (E-M) coupling. To differentiate the role of iNOS versus constitutive nitric oxide synthase (eNOS and nNOS) in Hcy-mediated nitrotyrosine generation and matrix remodeling in cardiac dysfunction, left ventricular (LV) tissue was analyzed from cystathionine beta synthase (CBS) heterozygote knockout, iNOS homozygote knockout, CBS,/+/iNOS,/, double knockout, and wild-type (WT) mice. The levels of nitrotyrosine, MMP-2 and -9 (zymographic analysis), and fibrosis (by trichrome stain) were measured. The endothelial-myocyte function was determined in cardiac rings. In CBS,/+ mice, homocysteine was elevated and in iNOS,/, mice, nitric oxide was significantly reduced. The nitrotyrosine and matrix metalloproteinase-9 (MMP-9) levels were elevated in double knockout and CBS,/+ as compared to WT mice. Although MMP-2 levels were similar in CBS,/+, iNOS,/,, and CBS,/+/iNOS,/,, the levels were three- to fourfold higher than WT. The levels of collagen were similar in CBS,/+ and iNOS,/,, but they were threefold higher than WT. Interesting, the levels of collagen increased sixfold in double knockouts, compared to WT, suggesting synergism between high Hcy and lack of iNOS. Left ventricular hypertrophy was exaggerated in the iNOS,/, and double knockout, and mildly increased in the CBS,/+, compared to WT mice. The endothelial-dependent relaxation was attenuated to the same extent in the CBS,/+ and iNOS,/,, compared to WT, but it was robustly blunted in double knockouts. The results concluded that homocysteine generated nitrotyrosine in the vicinity of endothelium, caused MMP activation and endothelium-myocyte uncoupling. The generation of nitrotyrosine was independent of iNOS. J. Cell. Biochem. 106: 119,126, 2009. © 2008 Wiley-Liss, Inc. [source] Mitochondrial mechanism of oxidative stress and systemic hypertension in hyperhomocysteinemiaJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 4 2005Neetu Tyagi Abstract Formation of homocysteine (Hcy) is the constitutive process of gene methylation. Hcy is primarily synthesized by de-methylation of methionine, in which s-adenosyl-methionine (SAM) is converted to s-adenosyl-homocysteine (SAH) by methyltransferase (MT). SAH is then hydrolyzed to Hcy and adenosine by SAH-hydrolase (SAHH). The accumulation of Hcy leads to increased cellular oxidative stress in which mitochondrial thioredoxin, and peroxiredoxin are decreased and NADH oxidase activity is increased. In this process, Ca2+ -dependent mitochondrial nitric oxide synthase (mtNOS) and calpain are induced which lead to cytoskeletal de-arrangement and cellular remodeling. This process generates peroxinitrite and nitrotyrosine in contractile proteins which causes vascular dysfunction. Chronic exposure to Hcy instigates endothelial and vascular dysfunction and increases vascular resistance causing systemic hypertension. To compensate, the heart increases its load which creates adverse cardiac remodeling in which the elastin/collagen ratio is reduced, causing cardiac stiffness and diastolic heart failure in hyperhomocysteinemia. J. Cell. Biochem. © 2005 Wiley-Liss, Inc. [source] Induction of oxidative stress by homocyst(e)ine impairs endothelial function,JOURNAL OF CELLULAR BIOCHEMISTRY, Issue 3 2001Vibhas S. Mujumdar Abstract Previous studies have demonstrated a relationship between hyperhomocysteinemia and endothelial dysfunction, reduced bioavailability of nitric oxide, elastinolysis and, vascular muscle cell proliferation. In vivo decreased nitric oxide production is associated with increased matrix metalloproteinase (MMP) activity and formation of nitrotyrosine. To test the hypothesis that homocysteine neutralizes vascular endothelial nitric oxide, activates metalloproteinase, causes elastinolysis and vascular hypertrophy, we isolated aortas from normotensive Wistar rats and cultured them in medium containing homocysteine, and calf serum for 14 days. Homocysteine-mediated impairment of endothelial-dependent vasodilatation was reversed by co-incubation of homocysteine with nicotinamide (an inhibitor of peroxinitrite and nitrotyrosine), suggesting a role of homocysteine in redox-mediating endothelial dysfunction and nitrotyrosine formation. The Western blot analysis, using anti-nitrotyrosine antibody, on aortic tissue homogeneates demonstrated decreased nitrotyrosine in hyperhomocysteinemic vessels treated with nicotinamide. Zymographic analysis revealed increased elastinolytic gelatinase A and B (MMP-2, -9) in homocysteine treated vessels and the treatment with nicotinamide decreases the homocysteine-induced MMP activation. Morphometric analyses revealed significant medial hypertrophic thickening (1.4,±,0.2-fold of control, P,=,0.03) and elastin disruption in homocysteine-treated vessels as compared to control. To determine whether homocysteine causes endothelial cell injury, cross-sections of aortas were analyzed for caspase activity by incubating with Ac-YVAD-AMC (substrate for apoptotic enzyme, caspase). The endothelium of homocysteine treated vessels, and endothelial cells treated with homocysteine, showed marked labeling for caspase. The length-tension relationship of homocysteine treated aortas was shifted to the left as compared to untreated aortas, indicating reduced vascular elastic compliance in homocysteine-treated vessels. Co-incubation of homocysteine and inhibitors of MMP, tissue inhibitor of metalloproteinase-4 (TIMP-4), and caspase, YVAD-CHO, improved vascular function. The results suggest that alteration in vascular elastin/collagen ratio and activation of MMP-2 are associated with decreased NO production in hyperhomocysteinemia. J. Cell. Biochem. 82:491,500, 2001. © 2001 Wiley-Liss, Inc. [source] Protective Effect of Vitamin E Against Ethanol-Induced Hyperhomocysteinemia, DNA Damage, and Atrophy in the Developing Male Rat BrainALCOHOLISM, Issue 7 2009Alireza Shirpoor Background:, Chronic alcoholism leads to elevated plasma and brain homocysteine (Hcy) levels, as demonstrated by clinical investigations and animal experiments. It has been posited that elevated levels of Hcy mediate DNA damage, brain atrophy, and excitotoxicity. The current study sought to elucidate the effect of vitamin E on ethanol-induced hyperhomocysteinemia, DNA damage, and atrophy in the developing hippocampus and cerebellum of rats. Methods:, Pregnant Wistar rats received ethanol with or without vitamin E from gestation day 7 throughout lactation. Weight changes in the brain, hippocampus and cerebellum, DNA damage, and Hcy levels in the plasma, hippocampus, and cerebellum of male offspring were measured at the end of lactation. Results:, The results revealed that along with a significant decrease in brain, cerebellum, and hippocampus weights in animals that received alcohol, the levels of DNA damage and Hcy significantly increased. Significant amelioration of brain atrophy and DNA damage as well as restoration of the elevated level of Hcy to that of controls were found in vitamin E-treated rats. Conclusions:, These findings strongly support the idea that ethanol intake by dams during pregnancy and lactation induces Hcy-mediated oxidative stress in the developing hippocampus and cerebellum of offspring rats, and that these effects can be alleviated by vitamin E as an antioxidant. [source] Homocysteine and cardiovascular disease: A review of current recommendations for screening and treatmentJOURNAL OF THE AMERICAN ACADEMY OF NURSE PRACTITIONERS, Issue 3 2005KarenL. Purpose To review the literature for, and provide advanced practice nurses (APNs) with, current recommendations for screening and treatment of hyperhomocysteinemia. Data sources Medscape literature search of selected research studies and related journal articles. Conclusions While data from most epidemiologic studies support the argument that hyperhomocysteinemia is an independent risk factor for cardiovascular disease, the debate continues as to when screening and treating patients is appropriate. The consensus is that more randomized controlled trials are needed to further study the benefits of routine screening and the efficacy of treating hyperhomocysteinemia. Implications for practice Until the results of ongoing clinical trials are available, APNs should follow the American Heart Association guidelines for screening for elevated levels of homocysteine and continue to promote a well-balanced diet that includes foods rich in folic acid as part of health promotion through primary prevention. [source] Effect of Chronic Alcohol Consumption on Total Plasma Homocysteine Level in RatsALCOHOLISM, Issue 3 2000Felix Stickel Background: Chronic alcoholism in humans is associated with the development of hyperhomocysteinemia, the mechanism of which remains unclear. Among the causes of hyperhomocysteinemia is depletion of folate, vitamin B12, or vitamin B6, Population-based studies indicate that folate is the strongest vitamin determinant of hyperhomocysteinemia and, in most settings, folate supplementation effectively lowers elevated homocysteine levels. However, it is not clear whether folate deficiency is the cause of alcoholrelated hyperhomocysteinemia. Methods: In the present study, 10 male Sprague Dawley® rats were fed ethanol-containing Lieber- DeCarli diets with 13 mg of folic acid per kilogram of diet. This represents a folate intake more than 20 times the basal requirement. Ethanol represented 36% of total energy, which yielded a concentration of 6.2% (vol/vol). The same number of rats were pair-fed with isocaloric control diets that contained an identical level of folate in which ethanol was entirely replaced by maltodextrin. Results: At the end of 4 weeks, alcohol-fed rats did not show any significant reduction in plasma or hepatic folate concentrations, plasma pyridoxal-5,-phosphate concentration, or plasma vitamin B12 concentration. On the other hand, alcohol-fed rats were significantly hyperhomocysteinemic (17.24 ± 4.63 ,mol/liter,p < 0.01) compared to the nonalcohol group (10.73 ± 2.76 ,mol/liter). Alcohol-fed rats also had a significantly lower hepatic S-adenosylmethionine and higher hepatic S-adenosylhomocysteine levels. Conclusions: Chronic alcohol consumption produces hyperhomocysteinemia by a mechanism that is related to interference with one-carbon metabolism, and not through vitamin depletion. [source] Hyperhomocysteinemia and low B vitamin levels are independently associated with venous thromboembolism: results from the EDITH study: a hospital-based case,control studyJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 4 2006E. OGER Summary.,Background:,Moderate hyperhomocysteinemia and B vitamins deficiency are thought to be risk factors for venous thromboembolism (VTE). The causality and independence of those associations are still questioned. Methods:,We measured fasting serum total homocysteine, folates, and vitamin B12 levels as well as 5,10-methylenetetrahydrofolate reductase (MTHFR) C677T genotypes in 467 patients hospitalized with a first well-documented deep vein thrombosis and/or pulmonary embolism not related to a major acquired risk factor and 467 controls matched for gender and age. Results:,Mild hyperhomocysteinemia, low serum folates, and vitamin B12 were associated with VTE independently of each other. In multivariate analysis, odds ratios (OR) (95% CI) for VTE associated with mild hyperhomocysteinemia (>15 ,mol L,1), low serum folates (,,4.9 nmol L,1), and vitamin B12 (, 253 pmol L,1) were 1.48 (1.05,2.08), 3.14 (1.35,7.32) and 1.42 (1.03,1.98), respectively. An MTHFRC677T genotype was not significantly associated with VTE; OR (95% CI): 1.13 (0.70,1.81) Conclusions:,The current data provides further knowledge in the complex relationship between hyperhomocysteinemia, low vitamin levels, and VTE. [source] Thrombophilia and pregnancy outcomesJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 8 2005I. PABINGER Summary., Pregnancy complications are still a challenge for physicians, because knowledge of pathomechanisms and prophylactic measures is still limited. In recent years thrombophilia as a risk factor for pregnancy complications has gained much attention in the scientific community. However, data on this topic in the literature are conflicting. Besides an established association between antiphospholipid antibodies and pregnancy loss, available data suggest additional associations for antithrombin deficiency, hyperhomocysteinemia and also for factor (F)V Leiden, prothrombin G20210A variation, and protein S-deficiency. The contribution of thrombophilia to the risk of pre-eclampsia is less well established and recent studies did not confirm earlier data suggesting an association between thrombophilia and pre-eclampsia. A limited number of prospective studies have failed to reveal an increased risk of pregnancy complications in unselected women with thrombosis risk factors. Low-molecular weight heparin (LMWH) seems to have a positive effect on pregnancy outcome after single or recurrent abortions, however, data from only one controlled trial are available. Experience in the prevention of pre-eclampsia by prophylactic heparin is very limited, and in addition, data on pregnancy complications in women with known heritable thrombophilia or a history of thrombosis are inconsistent. These women will usually have a favorable pregnancy outcome referring to the European Prospective Cohort on Thrombophilia Study. In conclusion, thrombophilia screening might be justified in women with pregnancy loss and treatment with LMWH might be considered in those with pregnancy loss and thrombophilia. Further prospective studies and controlled interventional trials are urgently needed. [source] The 894 G > T variant of endothelial nitric oxide synthase (eNOS) increases the risk of recurrent venous thrombosis through interaction with elevated homocysteine levelsJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 5 2004S. G. Heil Summary.,Background: Venous thrombosis is a multicausal disease involving both genetic as well as acquired risk factors. Hyperhomocysteinemia is associated with a 2-fold increased risk of recurrent venous thrombosis (RVT). Recently, the 894 G > T variant of endothelial nitric oxide synthase (eNOS) was postulated to be associated with hyperhomocysteinemia. Objectives: We hypothesized an interrelation of hyperhomocysteinemia, the eNOS 894 G > T variant and RVT risk. Methods: The eNOS 894 G > T variant was studied in 170 cases with a history of RVT and 433 controls from the general population. Results: The eNOS 894 TT genotype may increase RVT risk [odds ratio (OR) 1.3 (0.7,2.6)], but no association of the eNOS 894 G > T variant with elevated homocysteine was found in controls. Interestingly, in RVT cases the coexistence of both the 894 TT genotype and elevated tHcy levels (> 90th percentile) was more frequently present than in controls, which led to a substantially increased risk of recurrent venous thrombosis [fasting tHcy OR 5.3 (1.1,24.1), postload tHcy OR 6.5 (1.6,29.5)]. Conclusion: The results of the present study demonstrate that the eNOS 894 G > T variation interacts with elevated tHcy levels, leading to an increased risk of recurrent thrombotic events. This interaction points in the direction of S-nitrosation as a mechanism by which homocysteine exerts its detrimental effects on the hemostatic system. [source] The risk of recurrent venous thromboembolism among patients with high factor IX levelsJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 1 2003A. Weltermann Summary., High factor IX (FIX) is a risk factor of deep vein thrombosis. The impact of high FIX on the risk of recurrent venous thrombosis is unknown. We prospectively followed 546 patients after anticoagulation for a first spontaneous venous thromboembolism. Patients with a natural coagulation inhibitor deficiency, lupus anticoagulant or cancer were excluded. At 3 years, the likelihood of recurrence was 23% among patients with high FIX (exceeding the 75th percentile) compared with 11% among patients with lower levels. Among patients with high FIX, the relative risk of recurrence was 2.2 (95% CI: 1.3,3.6) before and was 1.6 (95% CI: 1.0,2.8) after adjustment for age, gender, duration of anticoagulation, FV Leiden, FII G20210A, high FVIII and hyperhomocysteinemia. Compared with patients with low factor IX (< 138 IU dL,1) and low FVIII (, 234 IU dL,1), the relative risk of recurrence was 1.5 among patients with high FIX and low FVIII, 2.7 among patients with low FIX and high FVIII and 6.6 among patients with high FIX and high FVIII. High levels of FIX confer an increased risk of recurrent venous thromboembolism and enhance the risk of recurrence among patients with high FVIII. [source] | ||||||||||||||||||||||||||||