Moderately elevated plasma homocysteine, methylenetetrahydrofolate reductase genotype, and risk for stroke, vascular dementia, and Alzheimer disease in Northern Ireland

Elevated plasma homocysteine level has been associated with increased risk for cardiovascular and cerebrovascular disease. Variation in the levels of this amino acid has been shown to be due to nutritional status and methylenetetrahydrofolate reductase (MTHFR) genotype.

Plasma glutathione peroxidase activity is reduced in haemodialysis patients

Cardiovascular disease is the major cause of morbidity and mortality in patients with end-stage renal failure. Increased free radical production and antioxidant depletion may contribute to the greatly increased risk of atherosclerosis in these patients. Glutathione peroxidase (GPX) is an important antioxidant, the plasma form of which is synthesized mainly in the kidney (eGPX). The aim of this study was to assess the activity of eGPX in patients with end-stage renal failure on haemodialysis. Venous blood was collected from 87 haemodialysis patients immediately prior to and after dialysis and from 70 healthy controls. Serum eGPX activity was measured using hydrogen peroxide as substrate and immunoreactivity determined by ELISA. eGPX activity was significantly reduced in dialysis patients when compared to controls (106 +/- 2.7 and 281 +/- 3.6 U/l respectively, p <0.001). Following haemodialysis, eGPX activity rose significantly to 146 +/- 3.8 U/l, p <0.001, although remaining below control values (p <0.005). Immunoreactive eGPX, however, was similar in all groups (pre-dialysis 14.10 +/- 1.26 microg/ml, post-dialysis 14.58 +/- 1.35 microg/ml, controls 15.20 +/- 1.62 microg/ml, p = NS). A decrease was observed in the specific activity of eGPX in patients when compared to controls (8.81 +/- 1.14, 10.71 +/- 1.54 and 21.97 +/- 1.68 U/mg respectively, p <0.0001). eGPX activity is impaired in patients undergoing haemodialysis and so may contribute to atherogenesis in renal failure.

Analysis of the association between diabetic nephropathy and polymorphisms in the aldose reductase gene in Type 1 and Type 2 diabetes mellitus

To investigate the association between polymorphisms of the aldose reductase gene and diabetic nephropathy in both Type 1 and Type 2 diabetes mellitus, and to carry out a meta-analysis of published results.

Community-living nonagenarians in northern ireland have lower plasma homocysteine but similar methylenetetrahydrofolate reductase thermolabile genotype prevalence compared to 70-89-year-old subjects

This cross-sectional study assessed relationships between plasma homocysteine, 'thermolabile' methylenetetrahydrofolatereductase (MTHFR) genotype, B vitamin status and measures of renal function in elderly (70-89 years) and nonagenarian (90+ years) subjects, with the hypothesis that octo/nonagenarian subjects who remain healthy into old age as defined by 'Senieur' status might show reduced genetic or environmental risk factors usually associated with hyperhomocysteinaemia. Plasma homocysteine was 9.1 micromol/l (geometric mean [GM]) for all elderly subjects. Intriguingly, homocysteine was significantly lower in 90+ (GM; 8.2 micromol/l) compared to 70-89-year-old subjects (GM; 9.8 micromol/l) despite significantly lower glomerular filtration rate (GFR) and serum B12 in nonagenarian subjects and comparable MTHFR thermolabile (TT) genotype frequency, folate and B6 status to 70-89-year-olds. For all elderly subjects, the odds ratio and 95% confidence intervals for plasma homocysteine being in the highest versus lowest quartile was 4.27 (2.04-8.92) for age 90 years, 3.4 (1.5-7.8) for serum folate 10.7nmol/l, 3.0 (0.9-10.2) for creatinine >140 compared

Glutathione peroxidase 1 genotype is associated with an increased risk of coronary artery disease

Objective Oxidative stress is implicated in the pathogenesis of many human diseases including atherosclerosis. Human glutathione peroxidase 1 (hgpx1) participates in limiting cellular damage caused by oxidation. A characteristic polyalanine sequence polymorphism in exon 1 of hgpx1 produces three alleles with five, six or seven alanine (ALA) repeats in this sequence. The objective of this study was to determine whether hgpx1 genotype is associated with an altered risk of coronary artery disease (CAD).

Methods The frequency of the ALA6 allele was determined in 207 men with angiographic evidence of significant CAD compared to a control group (n = 146), by analysing the lengths of polymerase chain reaction fragments containing the ALA repeat polymorphism. Additional information was collected on severity of CAD, presence or absence of a prior acute myocardial infarction (AMI), smoking status, body mass index (BMI) and other clinical data.

Results There was a significant association between individuals with at least one ALA6 allele and an increased risk of CAD after adjustment for age, BMI and smoking status (odds ratio, 2.07, 95% confidence interval, 1.08-3.99, P = 0.029). However, there was no association between hgpx1 genotype and a previous history of AMI or hgpx1 genotype and severity of CAD.

Conclusion We conclude that individuals possessing one or two ALA6 alleles appear to be at a modest increased risk of CAD. This observation merits further investigation in other patient populations.

Diabetic-like loss of corneal sensitivity in the 50% galactose fed rat is ameliorated with topical administration of an aldose reductase inhibitor

Purpose: To investigate the temporal course of corneal sensitivity loss & the role of aldose reductase inhibitors (ARI) in an animal model of diabetic ocular complications. Methods: Weanling male S-D rats were randomly grouped to received ad libitum water & diet consisting of Purina (#5001) w/ either: 50% starch (CON,n=15) or 50% D-galactose (GAL,n=30). Half the galactosemic rats (ARI,n=15) received topical 0.25% CT-112 (3x daily, 20µl, Senju Pharmaceutical Co., Japan). Control & remaining half of the galactosemic animals received equivalent doses of saline eyedrops. Rats were restrained w/o medication during sensitivity measurements conducted w/ a Cochet-Bonnet Aesthesiometer mounted on a micromanipulator. The end of the filament (0.012mm dia.), which applied a mean pressure of 0.96 g/mm perpendicular to the corneal surface at center, was in the plane of focus of a slit-lamp biomicroscope. Measurements were conducted by two investigators which were masked to the treatment group. The average blink-responses from 10 consecutive stimuli to each cornea were expressed as a percent. Results: Mean (±SD) baseline corneal sensitivity in all groups were similar (CON 73%±11, GAL 71%±15, ARI 74%±16). Corneal sensitivity in the galactosemic rat was decreased (p

Phase I and II biotransformation enzymes and polycyclic aromatic hydrocarbons in the Mediterranean mussel (Mytilus galloprovincialis, Lamarck, 1819) collected in front of an oil refinery

The aim of the present study was to investigate the responses of phase I and II biotransformation enzymes and levels of PAHs in the Mediterranean mussel (Mytilus galloprovincialis, Lamarck, 1819) collected from three sites at different distance from an oil refinery. Phase I enzyme activities as NAD(P)H-cyt c red, NADH ferry red, B(a)PMO and phase II as UDPGT. GST were measured in digestive gland while 16 PAHs (US-EPA) in whole soft tissue. An added value to the data obtained in the present study rely on the RDA analysis which showed close correlations between PAHs levels and phase I enzyme activities in mussels collected in front of the refinery. And again a significant spatial correlation between B(a)P levels and NADPH-cyt c red activities was observed using linear models. No differences among sites for B(a) PMO and phase II GST activities were observed, while the application of UDPGT as biomarkers requires further investigation. (C) 2012 Elsevier Ltd. All rights reserved.

Green tea supplementation increases glutathione and plasma antioxidant capacity in adults with the metabolic syndrome

Green tea, a popular polyphenol-containing beverage, has been shown to alleviate clinical features of the metabolic syndrome. However, its effects in endogenous antioxidant biomarkers are not clearly understood. Thus, we tested the hypothesis that green tea supplementation will upregulate antioxidant parameters (enzymatic and nonenzymatic) in adults with the metabolic syndrome. Thirty-five obese participants with the metabolic syndrome were randomly assigned to receive one of the following for 8 weeks: green tea (4 cups per day), control (4 cups water per day), or green tea extract (2 capsules and 4 cups water per day). Blood samples and dietary information were collected at baseline (0 week) and 8 weeks of the study. Circulating carotenoids (a-carotene, ß-carotene, lycopene) and tocopherols (a-tocopherol, ?-tocopherol) and trace elements were measured using high-performance liquid chromatography and inductively coupled plasma mass spectroscopy, respectively. Serum antioxidant enzymes (glutathione peroxidase, glutathione, catalase) and plasma antioxidant capacity were measured spectrophotometrically. Green tea beverage and green tea extract significantly increased plasma antioxidant capacity (1.5 to 2.3 µmol/L and 1.2 to 2.5 µmol/L, respectively; P <.05) and whole blood glutathione (1783 to 2395 µg/g hemoglobin and 1905 to 2751 µg/g hemoglobin, respectively; P <.05) vs controls at 8 weeks. No effects were noted in serum levels of carotenoids and tocopherols and glutathione peroxidase and catalase activities. Green tea extract significantly reduced plasma iron vs baseline (128 to 92 µg/dL, P <.02), whereas copper, zinc, and selenium were not affected. These results support the hypothesis that green tea may provide antioxidant protection in the metabolic syndrome.

Fosfomycin and tobramycin in combination downregulate nitrate reductase genes narG and narH, resulting in increased activity against Pseudomonas aeruginosa under anaerobic conditions

The activity of aminoglycosides, used to treat Pseudomonas aeruginosa respiratory infection in cystic fibrosis (CF) patients, is reduced under the anaerobic conditions that reflect the CF lung in vivo. In contrast, a 4:1 (w/w) combination of fosfomycin and tobramycin (F:T), under investigation for use in the treatment of CF lung infection, has increased activity against P. aeruginosa under anaerobic conditions. The aim of this study was to elucidate the mechanisms underlying the increased activity of F:T under anaerobic conditions. Microarray analysis was used to identify the transcriptional basis of increased F:T activity under anaerobic conditions, and key findings were confirmed by microbiological tests including nitrate utilization assays, growth curves and susceptibility testing. Notably, growth in sub-inhibitory concentrations of F:T, but not tobramycin or fosfomycin alone, significantly downregulated (p <0.05) nitrate reductase genes narG and narH, essential for normal anaerobic growth of P. aeruginosa. Under anaerobic conditions, F:T significantly decreased (p

Hydroxymethylglutaryl-CoA reductase inhibition with simvastatin in Acute lung injury to Reduce Pulmonary dysfunction (HARP-2) trial: study protocol for a randomized controlled trial

Background: Acute lung injury (ALI) is a common devastating clinical syndrome characterized by life-threatening respiratory failure requiring mechanical ventilation and multiple organ failure. There are in vitro, animal studies and pre-clinical data suggesting that statins may be beneficial in ALI. The Hydroxymethylglutaryl-CoA reductase inhibition with simvastatin in Acute lung injury to Reduce Pulmonary dysfunction (HARP-2) trial is a multicenter, prospective, randomized, allocation concealed, double-blind, placebo-controlled clinical trial which aims to test the hypothesis that treatment with simvastatin will improve clinical outcomes in patients with ALI.

Methods/Design: Patients fulfilling the American-European Consensus Conference Definition of ALI will be randomized in a 1: 1 ratio to receive enteral simvastatin 80 mg or placebo once daily for a maximum of 28 days. Allocation to randomized groups will be stratified with respect to hospital of recruitment and vasopressor requirement. Data will be recorded by participating ICUs until hospital discharge, and surviving patients will be followed up by post at 3, 6 and 12 months post randomization. The primary outcome is number of ventilator-free days to day 28. Secondary outcomes are: change in oxygenation index and sequential organ failure assessment score up to day 28, number of non pulmonary organ failure free days to day 28, critical care unit mortality; hospital mortality; 28 day post randomization mortality and 12 month post randomization mortality; health related quality of life at discharge, 3, 6 and 12 months post randomization; length of critical care unit and hospital stay; health service use up to 12 months post-randomization; and safety. A total of 540 patients will be recruited from approximately 35 ICUs in the UK and Ireland. An economic evaluation will be conducted alongside the trial. Plasma and urine samples will be taken up to day 28 to investigate potential mechanisms by which simvastatin might act to improve clinical outcomes.

Evaluating early administration of the hydroxymethylglutaryl-CoA reductase inhibitor simvastatin in the prevention and treatment of delirium in critically ill ventilated patients (MoDUS trial): Study protocol for a randomized controlled trial

Background: The incidence of delirium in ventilated patients is estimated at up to 82%, and it is associated with longer intensive care and hospital stays, and long-term cognitive impairment and mortality. The pathophysiology of delirium has been linked with inflammation and neuronal apoptosis. Simvastatin has pleiotropic properties; it penetrates the brain and, as well as reducing cholesterol, reduces inflammation when used at clinically relevant doses over the short term. This is a single centre randomised, controlled trial which aims to test the hypothesis that treatment with simvastatin will modify delirium incidence and outcomes. 

Methods/Design: The ongoing study will include 142 adults admitted to the Watford General Hospital Intensive Care Unit who require mechanical ventilation in the first 72 hours of admission. The primary outcome is the number of delirium- and coma-free days in the first 14 days. Secondary outcomes include incidence of delirium, delirium- and coma-free days in the first 28 days, days in delirium and in coma at 14 and 28 days, number of ventilator-free days at 28 days, length of critical care and hospital stay, mortality, cognitive decline and healthcare resource use. Informed consent will be taken from patient's consultee before randomisation to receive either simvastatin (80 mg) or placebo once daily. Daily data will be recorded until day 28 after randomisation or until discharge from the ICU if sooner. Surviving patients will be followed up on at six months from discharge. Plasma and urine samples will be taken to investigate the biological effect of simvastatin on systemic markers of inflammation, as related to the number of delirium- and coma-free days, and the potential of cholinesterase activity and beta-amyloid as predictors of the risk of delirium and long-term cognitive impairment. 

Discussion: This trial will test the efficacy of simvastatin on reducing delirium in the critically ill. If patients receiving the statin show a reduced number of days in delirium compared with the placebo group, the inflammatory theory implicated in the pathogenesis of delirium will be strengthened. 

Proteomics and in silico approaches to extend understanding of the glutathione transferase superfamily of the tropical liver fluke Fasciola gigantica

Fasciolosis is an important foodborne, zoonotic disease of livestock and humans, with global annual health and economic losses estimated at several billion US$. Fasciola hepatica is the major species in temperate regions, while F. gigantica dominates in the tropics. In the absence of commercially available vaccines to control fasciolosis, increasing reports of resistance to current chemotherapeutic strategies and the spread of fasciolosis into new areas, new functional genomics approaches are being used to identify potential new drug targets and vaccine candidates. The glutathione transferase (GST) superfamily is both a candidate drug and vaccine target. This study reports the identification of a putatively novel Sigma class GST, present in a water-soluble cytosol extract from the tropical liver fluke F. gigantica. The GST was cloned and expressed as an enzymically active recombinant protein. This GST shares a greater identity with the human schistosomiasis GST vaccine currently at Phase II clinical trials than previously discovered F. gigantica GSTs, stimulating interest in its immuno-protective properties. In addition, in silico analysis of the GST superfamily of both F. gigantica and F. hepatica has revealed an additional Mu class GST, Omega class GSTs, and for the first time, a Zeta class member.