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tHcy Levels (thcy + level)
Kinds of tHcy Levels Selected AbstractsPlasma 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] The MTHFR C677T polymorphism confers a high risk for stroke in both homozygous and heterozygous T allele carriers with Type 2 diabetesDIABETIC MEDICINE, Issue 5 2006M. P. Hermans Abstract Objective Individuals with Type 2 diabetes are at increased risk of stroke. Plasma homocysteine (tHcy) is an independent risk factor for cardiovascular (CV) disease. The methylene,tetrahydrofolate reductase (MTHFR) gene polymorphism (thermolabile variant C677T) is associated with CV risk, partly as a result of increased Hcy, especially in homozygous subjects. Aim To relate the occurrence of the MTHFR polymorphism with stroke prevalence by examining allelic frequency and genotype distribution in 165 subjects with Type 2 diabetes studied for the presence of thermolabile C677T MTHFR mutation. Results Mean age was 67.7 years, and tHcy 18.2 µmol/l. T allele frequency was 38.5%. MTHFR genotypes were: normal (CC) 40%; heterozygous (CT) 43%; homozygous (TT) 17%. Serum levels of folic acid and B12 vitamin were within normal limits. Stroke prevalence was 14%. Sixty-four per cent of stroke-free subjects had the normal C allele vs. 46% in stroke subjects. The frequencies of genotypes (CC-CT-TT) were (%): 44-41-15 in stroke-free vs. 17-57-26 in stroke patients. Coronary (CAD) and peripheral artery disease (PAD) were common in all groups, with no differences according to genotypes. Stroke prevalence was markedly higher in genotypes CT and TT (18 and 21%) compared with CC (6%). Mean tHcy levels were higher in TT subjects. Conclusion The allelic frequency of C677T MTHFR mutation in Type 2 diabetes subjects with stroke is markedly different from that of subjects without stroke. Genotypic characteristics suggest that C677T MTHFR mutation confers a higher risk for stroke to both homozygous and heterozygous T allele carriers that cannot be ascribed solely to raised tHcy and/or lower folate status in CT subjects, nor to phenotypic expression of conventional risk factors for stroke. The impact of the MTHFR polymorphism on stroke may result from T allele-linked deleterious effects, or C allele-linked protection. Confirmatory studies are warranted, as this cohort was not randomly selected, and a type 1 error cannot be ruled out. [source] Hyperhomocysteinemia 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] 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] Homocysteine Level and Cognitive Function in Patients with Arterial Disease: The Second Manifestations of ARTerial Disease StudyJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 4 2006Fleur van A. Raamt MD OBJECTIVES: To assess the relationship between total plasma homocysteine (tHcy) level and cognitive function in patients with manifest arterial disease. DESIGN: Cross-sectional. SETTING: Patients with symptomatic cerebrovascular disease, cardiovascular disease, peripheral arterial disease, or abdominal aortic aneurysm included in the Second Manifestations of ARTerial disease study, a single-center, longitudinal study with an extensive screening program at baseline. PARTICIPANTS: Three hundred forty-five consecutively included patients, mean age 59. MEASUREMENTS: The patients underwent an extensive neuropsychological test. The cognitive domains assessed were memory, executive function, attention, and visuoperception and construction. Each raw score was transformed into standardized z-scores, and a sum score for global cognitive function was determined. Risk factors and vascular damage were measured in detail. RESULTS: Linear regression showed that elevated levels of tHcy were related to lower global cognitive function (,=,0.065, 95% confidence interval (CI)=,0.116 to ,0.013) and, more specifically, lower performance on memory (,=,0.078, 95% CI=,0.155 to ,0.002), attention (,=,0.079, 95% CI=,0.163 to ,0.005), and visuoperception and construction (,=,0.125, 95% CI=,0.236 to ,0.014) per standard deviation increase in tHcy (SD=6.4 mol/L), after adjustment for age, sex, educational level, extent of atherosclerosis, and location of vascular disease. Silent cerebral infarcts did not influence this relationship. CONCLUSION: A relationship was found between tHcy levels and cognitive function that was independent of extent and location of arterial disease. The results suggest that vascular mechanisms are not responsible for the relationship between tHcy and cognitive function. [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] Reduced in vivo oxidative stress following 5-methyltetrahydrofolate supplementation in patients with early-onset thrombosis and 677TT methylenetetrahydrofolate reductase genotypeBRITISH JOURNAL OF HAEMATOLOGY, Issue 1 2005Antonio Coppola Summary The protective role of folate in vascular disease has been related to antioxidant effects. In 45 patients with previous early-onset (at age <50 years) thrombotic episodes and the 677TT methylenetetrahydrofolate reductase genotype, we evaluated the effects of a 28d-course (15 mg/d) of 5-methyltetrahydrofolate (MTHF) on homocysteine metabolism and on in vivo generation of 8-iso-prostaglandin F2, (8-iso-PGF2,), a reliable marker of oxidative stress. At baseline, patients' fasting total homocysteine (tHcy) was 11·5 ,mol/l (geometric mean) and urinary excretion of 8-iso-PGF2, was 304 pg/mg creatinine, with the highest metabolite levels in the lowest quartile of plasma folate distribution (P < 0·05). After 5-MTHF supplementation, plasma folate levels increased approximately 13-fold (P < 0·0001 versus baseline); tHcy levels (6·7 ,mol/l, P < 0·0001) and urinary 8-iso-PGF2, (254 pg/mg creatinine, P < 0·001) were both significantly lowered, their reduction being proportional to baseline values (r = 0·98 and r = 0·77, respectively) and maximal in patients with the lowest pre-supplementation folate levels (P < 0·05). The effects on folate (P < 0·0001) and tHcy (P = 0·0004) persisted for at least up to 2 months after withdrawing 5-MTHF. In parallel with long-lasting tHcy-lowering effects, a short-course 5-MTHF supplementation reduces in vivo formation of 8-iso-PGF2, in this population, supporting the antioxidant protective effects of folate in vascular disease. [source] |