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Background and Aims Mulibrey nanism (MUL) is a multiorgan disease caused by recessive mutations in the TRIM37 gene. Chronic heart failure and hepatopathy are major determinants of prognosis in MUL patients, which prompted us to study liver biochemistry and pathology in a national cohort of MUL patients. Methods Clinical, laboratory and imaging data were collected in a cross-sectional survey and retrospectively from hospital records. Liver histology and immunohistochemistry for 10 biomarkers were assessed. Results Twenty-one MUL patients (age 1-51 years) with tumour suspicion showed moderate congestion, steatosis and fibrosis in liver biopsies and marginally elevated levels of serum GGT, AST, ALT and AST to platelet ratio index (APRI) in 20%-66%. Similarly, GGT, AST, ALT and APRI levels were moderately elevated in 12%-69% of 17 MUL patients prior to pericardiectomy. In a cross-sectional evaluation of 36 MUL outpatients, GGT, total bilirubin and galactose half-life (Gal1/2) correlated with age (r = 0.45, p = .017; r = 0.512, p = .007; r = 0.44, p = .03 respectively). The frequency of clearly abnormal serum values of 15 parameters analysed, however, was low even in patients with signs of restrictive cardiomyopathy. Transient elastography (TE) of the liver revealed elevated levels in 50% of patients with signs of heart failure and TE levels correlated with several biochemistry parameters. Biomarkers of fibrosis, sinusoidal capillarization and hepatocyte metaplasia showed increased expression in autopsy liver samples from 15 MUL patients. Conclusion Liver disease in MUL patients was characterized by sinusoidal dilatation, steatosis and fibrosis with individual progression to cirrhosis and moderate association of histology with cardiac function, liver biochemistry and elastography.

Oncology, driven by new discoveries in pharmacology, technology and information technology, is advancing at an unprecedented rate. However, the most basic process that is at the core of applied oncology is the process of making efficient oncology decisions. Decision making influences the choice of available treatment, patient satisfaction and oncological outcome. The decision is multidisciplinary and is based on the knowledge, experience and personality of many experts who make up the dream team of the health organization they serve. The clinical decision-making process is the quintessence of daily clinical practice. Medical decision-making for cancer patients can be highly complex and multifaceted, involving diagnostic and therapeutic uncertainties, patient preferences and values, and certainly includes healthcare environment.

Graphical abstract, Highlights • Ethyl paraben (EtP) concentrations above the LOD were found in 88% of the placentas. • Child BMI z-scores were inversely associated with placental EtP exposure. • Placental EtP was associated with cord blood γ-glutamyltransferase (GGT) activity. • Cord blood glucose showed an inverse relationship with placental EtP. • Placental EtP was associated with methylation of cg08612779 annotated to GGT7., Background Parabens are used as antimicrobial preservatives in personal care products. Few studies have dealt with adverse health outcomes, transplacental transfer, and obesogenic effects of prenatal exposure to parabens. We examined the association between placental paraben levels and cord blood metabolic biomarkers, considering modulating effects of maternal pre-pregnancy BMI and underlying epigenetic mechanisms, and investigated longitudinal effects of in utero paraben exposure on early childhood trajectories of BMI z-scores. Methods Placental concentrations of four parabens [methyl (MeP), ethyl (EtP), propyl (PrP), and butyl (BuP)] were measured by ultra-performance liquid chromatography/tandem mass spectrometry in 229 placentas of the ENVIRONAGE birth cohort. The association with cord blood metabolic biomarkers [glucose, insulin, γ-glutamyltransferase (GGT), high-density and low-density lipoprotein (HDL and LDL)] was analyzed in multiple regression models with two different sets of, a priori selected potential confounders, additionally stratified for different maternal BMI groups and assessed by causal mediation analysis. The association between placental paraben concentration and differential DNA methylation of CpGs annotated to GGT and longitudinal measurements of BMI z-scores were investigated with adjusted linear mixed models. Results The geometric means of placental MeP, EtP, PrP, and BuP levels above the limit of detection (LOD) were 4.42, 1.32, 1.51, and 0.35 ng/g respectively, with only EtP showing sufficient (88%) measurements above LOD for further analyses. An interquartile ratio (IQR) increase in placental EtP was associated with an increase of 12.61 % (95% CI: 1.80 24.57) in the geometric mean of cord GGT activity, and with a decrease of −3.64 % (95% CI: −6.80 to −0.39) in the geometric mean of cord glucose. Placental EtP levels were significantly associated with hypermethylation of cg08612779 annotated to GGT7 after correcting for multiple testing (ß = 0.0017, p = 0.049). An interquartile ratio (IQR) increment in placental EtP was associated with a decrease in longitudinal BMI z-score of 0.27 points (95% CI: −0.46 to −0.088). Conclusion Prenatal EtP exposure may affect early childhood BMI. The association of placental EtP with cord blood GGT and glucose levels provides a starting point for further research on mechanisms of paraben-related metabolic processes in utero.

Background: Self-reported alcohol consumption is an established risk factor for cardiovascular disease (CVD). Carbohydrate deficient transferrin (CDT) is an established objective marker of excessive alcohol consumption, but data on its prospective association with CVD are lacking. We aimed to evaluate the associations of self-reported alcohol consumption and CDT (expressed as %CDT, a more reliable marker than absolute CDT levels) with CVD risk.Materials and methods: In the PREVEND prospective study of 5,206 participants (mean age, 53 years; 47.7% males), alcohol consumption by self-reports, absolute CDT measured using the Siemens nephelometric assay and %CDT calculated as the percentage of total transferrin concentrations, were assessed at baseline. Alcohol consumption was classified into 5 categories: abstention (reference), light, light–moderate, moderate and heavy alcohol consumption. Hazard ratios (HRs) (95% confidence intervals [CI]) for first CVD events were estimated.Results: Mean (SD) of %CDT was 1.59 (0.54) %. During a median follow-up of 8.3 years, 326 first CVD events were recorded. Compared with abstainers, the multivariable-adjusted HRs (95% CIs) of CVD for light, light–moderate, moderate and heavy alcohol consumption were 0.66 (0.46-0.95), 0.83 (0.62-1.11), 0.83 (0.61-1.14) and 0.80 (0.48-1.36), respectively. Light alcohol consumption was associated with reduced coronary heart disease risk 0.62 (0.40-0.96), whereas light-moderate alcohol consumption was associated with reduced stroke risk 0.45 (0.24-0.83). The association of %CDT with CVD risk was not significant. Conclusions: Our findings confirm the established association between self-reported light to moderate alcohol consumption and reduced CVD risk. However, %CDT within the normal reference range may not be a risk indicator for CVD.

Background: Stopping nucleos(t)ide analogues (NA) after hepatitis B e antigen (HBeAg) seroconversion is associated with high relapse rates in Asian patients, but data in Caucasian cohorts are scarce. Clinical course, outcomes and immunological aspects of chronic hepatitis B infections differ substantially between distinct ethnicities. Aim: The aim of this study was to determine relapse rates, factors predicting relapse and clinical outcomes after nucleos(t)ide analogue cessation in a large, predominantly Caucasian cohort of chronic hepatitis B patients with nucleos(t)ide analogue-induced HBeAg seroconversion. Methods: This is a nationwide observational cohort study including HBeAg positive, mono-infected chronic hepatitis B patients with nucleos(t)ide analogue-induced HBeAg seroconversion from 18 centres in Belgium. Results: A total of 98 patients with nucleo(s)tide analogue-induced HBeAg seroconversion were included in the study. Of the 62 patients who stopped treatment after a median consolidation treatment of 8 months, 30 relapsed. Higher gamma-glutamyl transferase levels at both treatment initiation (HR 1.004; P = 0.001 per unit increment) and HBeAg seroconversion (HR 1.006; P = 0.013 per unit increment) were associated with an increased risk of clinically significant relapse in a multivariate Cox regression model. Treatment cessation led to liver-related death in 2 patients, of whom one showed a severe flare. Of the patients who continued treatment after HBeAg seroconversion, none relapsed or developed severe hepatic outcomes. Conclusion: Treatment withdrawal in Caucasian chronic hepatitis B patients after nucleos(t)ide analogue-induced HBeAg seroconversion results in viral relapses in more than half of patients with potential fatal outcomes. These real-world data further lend support to preferentially continue NA treatment after HBeAg seroconversion until HBsAg loss. Foundation Against Cancer Belgium, Grant/Award Number: 2014-087

ObjectiveThe prevalence of obesity increases with age and is higher in each younger generation (unfavorable generation shift). This may influence patterns of oxidative stress and inflammation. Age-related changes and generation shifts in markers of oxidative stress and inflammation were investigated, specifically addressing the role of body mass index (BMI).MethodsFour generations (aged 26-35, 36-45, 46-55, and 56-65 at baseline) (N = 5,155) were examined every 5 years for 15 years between 1993 and 2012. Random coefficient analyses were used to study age-related changes and generation shifts in BMI, -glutamyltransferase (GGT), uric acid (UA), and C-reactive protein (CRP).ResultsLevels of BMI, UA, and CRP increased in all generations up to age 75, whereas GGT increased up to age 55. No consistent generation shifts were observed for GGT, UA, and CRP (P 0.05). Participants with a stable BMI (change 1 kg/m(2)/15 years) had either no or small increases with age in GGT, UA, and CRP, whereas participants with increasing BMI (increase >1 kg/m(2)/15 years) had much larger increases (P ConclusionsThe unfavorable age-related changes in obesity-related biochemical markers, particularly among individuals with increasing BMI, show the importance of maintaining a healthy weight to improve population levels of oxidative stress and inflammation.

Non-alcoholic fatty liver disease (NAFLD) covers a spectrum of liver disease from simple steatosis to non-alcoholic steatohepatitis (NASH) and cirrhosis. NAFLD is commonly associated with features of the metabolic/insulin resistance syndrome ('Metabolic/Obese NAFLD') and may therefore predict type 2 diabetes (T2DM). For this review, we searched for prospective studies examining whether NAFLD predicts T2DM, and if so, whether this occurs independently of factors such as age and obesity. These studies included NAFLD diagnosed by ultrasonography (n = 6) or liver enzymes (n = 14). All ultrasonography studies found NAFLD to predict the risk of T2DM independently of age, and in 4 out of 6 studies NAFLD was also a predictor independently of BMI. NAFLD was a predictor of T2DM in all 14 studies where NAFLD was diagnosed by liver enzymes. In 12 of these studies, ALT or AST or GGT were significant predictors of T2DM risk, independently of age and BMI. NAFLD, however, is heterogeneous and may also be caused by common genetic variants. The I148M variant in PNPLA3 and the E167K variant in TM6SF2 are both associated with increased liver fat content, but not features of the metabolic/insulin resistance syndrome. These genetic forms of NAFLD predict NASH and cirrhosis but not T2DM. Taken together these data imply that 'Metabolic/Obese NAFLD' predicts T2DM independently of age and obesity and support the role of hepatic insulin resistance in the pathogenesis of this disease. (C) 2016 Elsevier Ltd. All rights reserved.

[Aim]: Our aim is to demonstrate that a healthy diet might reduce the relation between adiposity and inflammation, whereas an unhealthy diet may increase the effect of adiposity on inflammatory biomarkers., [Methods]: In 618 adolescents (13–17 years) of the European HELENA study, data were available on body composition, a set of inflammation markers, and food intake determined by a self-administered computerized 24-h recall. A 9-point Mediterranean diet score and an antioxidant-rich diet score were used as dietary parameters and tested as moderator. Total body fat was represented by the sum of six skinfold thicknesses and central adiposity by waist circumference. A set of inflammation-related biomarkers was used as outcome: a pro/anti-inflammatory interleukins ratio, TGFβ-1, C-reactive protein, TNF-α, 3 cell adhesion molecules, and 3 types of immune cells; gamma-glutamyltransferase (GGT) and homocysteine were used as cardiovascular disease risk biomarkers, and alanine transaminase (ALT) as liver dysfunction biomarker. Multiple linear regression analyses tested moderation by diet in the adiposity-inflammation association and were adjusted for age, sex, country, puberty, socioeconomic status., [Results]: Both the Mediterranean and antioxidant-rich diet, and overall and central adiposity, were important in the moderation. Diet was a significant protective moderator in the effect of adiposity on the pro/anti-inflammatory interleukins ratio, TGFβ-1, GGT, and ALT., [Conclusion]: In conclusion, in some cases, a diet rich in antioxidants and essential nutrients may attenuate the concentration of inflammatory biomarkers caused by adiposity, whereas a poor diet appears to contribute to the onset of early oxidative stress signs., The HELENA Study was carried out with the financial support of the European Community Sixth RTD Framework Programme (Contract FOODCT-2005-007034).

Background Moderate alcohol consumption has been associated with a lower risk of cardiovascular disease (CVD) and all‐cause mortality compared with heavy drinkers and abstainers. To date, studies have relied on self‐reported consumption, which may be prone to misclassification. Urinary ethyl glucuronide (EtG) is an alcohol metabolite and validated biomarker for recent alcohol consumption. We aimed to examine and compare the associations of self‐reported alcohol consumption and EtG with CVD and all‐cause mortality. Methods and Results In 5676 participants of the PREVEND (Prevention of Renal and Vascular End‐Stage Disease) study cohort, EtG was measured in 24‐hour urine samples and alcohol consumption questionnaires were administered. Participants were followed up for occurrence of first CVD and all‐cause mortality. Cox proportional hazards regression models, adjusted for age, sex, and CVD risk factors, were fitted for self‐reported consumption, divided into 5 categories: abstention, 1 to 4 units/month (reference), 2 to 7 units/week, 1 to 3 units/day, and ≥4 units/day. Similar models were fitted for EtG, analyzed as both continuous and categorical variables. Follow‐up times differed for CVD (8 years; 385 CVD events) and all‐cause mortality (14 years; 724 deaths). For both self‐reported alcohol consumption and EtG, nonsignificant trends were found toward J‐shaped associations between alcohol consumption and CVD, with higher risk in the lowest (hazard ratio for abstention versus 1–4 units/month, 1.42; 95% CI, 1.02–1.98) and highest drinking categories (hazard ratio for ≥4 units/day versus 1–4 units/month, 1.11; 95% CI, 0.68–1.84). Neither self‐report nor EtG was associated with all‐cause mortality. Conclusions Comparable associations with CVD events and all‐cause mortality were found for self‐report and EtG. This argues for the validity of self‐reported alcohol consumption in epidemiologic research.

Background The role of dietary antioxidants and plasma oxidant-antioxidant status in low-grade chronic inflammation and adipocytokine levels is not established yet. Objectives We aimed to evaluate whether total dietary antioxidant capacity (assessed by dietary ferric reducing antioxidant potential (FRAP)), serum uric acid (UA) and gamma glutamyltransferase (GGT) were associated with low-grade chronic inflammation and circulating adipocytokines. Methods Data of 4506 participants aged ≥ 55 years from the Rotterdam Study were analyzed. Baseline (1990–1993) FRAP score was assessed by a food frequency questionnaire. Baseline UA and GGT levels were assessed in non-fasting serum samples. Serum high sensitivity C-reactive protein (hs-CRP) was measured at baseline and 10 years later. Plasma leptin, adiponectin, plasminogen activator inhibitor-1 (PAI-1) and resistin levels were assessed 10 years later.Results A high FRAP score was associated with lower levels of UA and GGT. Overall, no association was found between FRAP and hs-CRP levels. FRAP score was associated with lower levels of leptin and PAI-1, higher levels of adiponectin, and no difference in resistin levels. Increased levels of UA were associated with higher levels of hs-CRP, PAI-1 and leptin; lower levels of adiponectin and no difference in resistin levels. Similarly, GGT was associated with higher levels of hs-CRP whereas no association was observed between GGT and adipocytokines. Conclusion These findings suggest that overall antioxidant capacity of diet and low levels of UA are associated with circulating adipocytokines whereas no consistent association was found with hs-CRP.

final draft, peerReviewed

Objective To quantify the dose-response relation between consumption of whole grain and specific types of grains and the risk of cardiovascular disease, total cancer, and all cause and cause specific mortality. Data sources PubMed and Embase searched up to 3 April 2016. Study selection Prospective studies reporting adjusted relative risk estimates for the association between intake of whole grains or specific types of grains and cardiovascular disease, total cancer, all cause or cause specific mortality. Data synthesis Summary relative risks and 95% confidence intervals calculated with a random effects model. Results 45 studies (64 publications) were included. The summary relative risks per 90 g/day increase in whole grain intake (90 g is equivalent to three servings—for example, two slices of bread and one bowl of cereal or one and a half pieces of pita bread made from whole grains) was 0.81 (95% confidence interval 0.75 to 0.87; I 2 =9%, n=7 studies) for coronary heart disease, 0.88 (0.75 to 1.03; I 2 =56%, n=6) for stroke, and 0.78 (0.73 to 0.85; I 2 =40%, n=10) for cardiovascular disease, with similar results when studies were stratified by whether the outcome was incidence or mortality. The relative risks for morality were 0.85 (0.80 to 0.91; I 2 =37%, n=6) for total cancer, 0.83 (0.77 to 0.90; I 2 =83%, n=11) for all causes, 0.78 (0.70 to 0.87; I 2 =0%, n=4) for respiratory disease, 0.49 (0.23 to 1.05; I 2 =85%, n=4) for diabetes, 0.74 (0.56 to 0.96; I 2 =0%, n=3) for infectious diseases, 1.15 (0.66 to 2.02; I 2 =79%, n=2) for diseases of the nervous system disease, and 0.78 (0.75 to 0.82; I 2 =0%, n=5) for all non-cardiovascular, non-cancer causes. Reductions in risk were observed up to an intake of 210-225 g/day (seven to seven and a half servings per day) for most of the outcomes. Intakes of specific types of whole grains including whole grain bread, whole grain breakfast cereals, and added bran, as well as total bread and total breakfast cereals were also associated with reduced risks of cardiovascular disease and/or all cause mortality, but there was little evidence of an association with refined grains, white rice, total rice, or total grains. Conclusions This meta-analysis provides further evidence that whole grain intake is associated with a reduced risk of coronary heart disease, cardiovascular disease, and total cancer, and mortality from all causes, respiratory diseases, infectious diseases, diabetes, and all non-cardiovascular, non-cancer causes. These findings support dietary guidelines that recommend increased intake of whole grain to reduce the risk of chronic diseases and premature mortality.

INTRODUCTION: Serum liver biomarkers (gamma-glutamyl transferase, GGT; alanine aminotransferase, ALT; aspartate aminotransferase, AST; alkaline phosphatase, ALP; total bilirubin) are used as indicators of liver disease, but there is currently little data on their prospective association with risk of hepatobiliary cancers.METHODS: A nested-case control study was conducted within the prospective EPIC cohort (>520,000 participants, 10 European countries). After a mean 7.5 mean years of follow-up, 121 hepatocellular carcinoma (HCC), 34 intrahepatic bile duct (IHBC) and 131 gallbladder and biliary tract (GBTC) cases were identified and matched to 2 controls each. Circulating biomarkers were measured in serum taken at recruitment into the cohort, prior to cancer diagnosis. Multivariable adjusted conditional logistic regression was used to calculate odds ratios and 95% confidence intervals (OR; 95%CI).RESULTS: In multivariable models, 1SD increase of each log-transformed biomarker was positively associated with HCC risk (OR(GGT)=4.23, 95%CI:2.72-6.59; OR(ALP)=3.43, 95%CI:2.31-5.10;OR(AST)=3.00, 95%CI:2.04-4.42; OR(ALT)=2.69, 95%CI:1.89-3.84; OR(Bilirubin)=2.25, 95%CI:1.58-3.20). Each liver enzyme (OR(GGT)=4.98; 95%CI:1.75-14.17; OR(AST)=3.10, 95%CI:1.04-9.30; OR(ALT)=2.86, 95%CI:1.26-6.48, OR(ALP)=2.31, 95%CI:1.10-4.86) but not bilirubin (OR(Bilirubin)=1.46,95%CI:0.85-2.51) showed a significant association with IHBC. Only ALP was significantly associated with GBTC risk (OR(ALP)=1.59, 95%CI:1.20-2.09).CONCLUSION: This study shows positive associations between circulating liver biomarkers in sera collected prior to cancer diagnoses and the risks of developing HCC or IHBC, but not GBTC.

BACKGROUND: Higher coffee intake has been purportedly related to a lower risk of liver cancer. However, it remains unclear whether this association may be accounted for by specific biological mechanisms.OBJECTIVE: We aimed to evaluate the potential mediating roles of inflammatory, metabolic, liver injury, and iron metabolism biomarkers on the association between coffee intake and the primary form of liver cancer-hepatocellular carcinoma (HCC).DESIGN: We conducted a prospective nested case-control study within the European Prospective Investigation into Cancer and Nutrition among 125 incident HCC cases matched to 250 controls using an incidence-density sampling procedure. The association of coffee intake with HCC risk was evaluated by using multivariable-adjusted conditional logistic regression that accounted for smoking, alcohol consumption, hepatitis infection, and other established liver cancer risk factors. The mediating effects of 21 biomarkers were evaluated on the basis of percentage changes and associated 95% CIs in the estimated regression coefficients of models with and without adjustment for biomarkers individually and in combination.RESULTS: The multivariable-adjusted RR of having ≥4 cups (600 mL) coffee/d compared with CONCLUSION: These data suggest that the inverse association of coffee intake with HCC risk was partly accounted for by biomarkers of inflammation and hepatocellular injury.

1 Dipartimento di Agronomia Animali Alimenti Risorse Naturali e Ambiente (DAFNAE), University of Padova, Legnaro, Italy, 2 Research Laboratory for Biotechnology and Biochemistry, Kathmandu, Nepal, 3 GRADE (Global Research Arch for Developing Education) Academy Private Limited, Birgunj, Nepal, 4 Organization for Educational Initiatives, University of Tsukuba, Tsukuba, Japan, 5 Department of Anatomy I, Showa University School of Medicine, Shinagawa, Japan

Renal cell carcinoma (RCC) diagnosis is mostly achieved incidentally by imaging provided for unrelated clinical reasons. The surgical management of localized tumors has reported excellent results. The therapy of advanced RCC has evolved considerably over recent years with the widespread use of the so-called “targeted therapies.” The identification of molecular markers in body fluids (e.g., sera and urine), which can be used for screening, diagnosis, follow-up, and monitoring of drug-based therapy in RCC patients, is one of the most ambitious challenges in oncologic research. Although there are some promising reports about potential biomarkers in sera, there is limited available data regarding urine markers for RCC. The following review reports some of the most promising biomarkers identified in the biological fluids of RCC patients.

The aim of our work was to evaluate the enzymatic pathways involved in the release of nitric oxide and in the vasorelaxant effect of S-nitrosothiols (RSNO). We were interested in two enzymes: the gamma-glutamyltransferase (GGT) and the protein disulfide isomerase (PDI), because they play an important role in RSNO denitrosation. Two RSNO were studied: S-nitrosoglutathione (GSNO), an endogenous mononitrosothiol, and S,S'-dinitrosobucillamine (BUC(NO)2), a new dinitrosothiol. We synthesized RSNO and we structurally characterized these products. The resulting data are consistent with the expected structure. Our products have a high purity (>97%) and a limited amount of impurities allowing their suitable use in biological experiments. The vasorelaxant effects of RSNO and the involvement of GGT and PDI were evaluated. The results indicate that purified GGT and PDI denitrosate GSNO in vitro. Furthermore, we demonstrated by using an ex vivo model consisting in an aortic ring isolated from Wistar rat that the vasorelaxant effect of GSNO (EC50=3,2±0,5.10-7 M) was dependent on the endothelium and GGT and PDI activities. As concerns BUC(NO)2, this dinitrosothiol catabolized in vitro by PDI, is more potent (EC50=2,2±0,2.10-8 M) than the most of nitrosothiols described in the literature. This vasorelaxation effect was dependent on PDI activity. In conclusion, our data led to a better understanding of the enzymatic mechanisms involved in the vascular effects of RSNO, which will permit, in physiopathological context, to optimize the choice of the best RSNO for use in a therapeutic purpose; L'objectif de notre travail a consisté en l'étude des mécanismes enzymatiques impliqués dans la libération de l'oxyde nitrique à partir des S-nitrosothiols (RSNO) et dans leurs effets vasorelaxants. Notre intérêt porte sur deux enzymes : la gamma-glutamyltransférase (GGT) et la protéine disulfure isomérase (PDI) car elles jouent un rôle important dans la dénitrosation des RSNO. Nous avons choisi d'étudier la dénitrosation de deux RSNO : le S-nitrosoglutathion (GSNO), un mononitrosothiol endogène et la S,S'-dinitrosobucillamine (BUC(NO)2), un nouveau dinitrosothiol. Nous avons synthétisé ces RSNO et nous avons vérifié la nature du produit obtenu par une caractérisation physico-chimique complète. Les analyses ont montré que ces RSNO présentent une pureté élevée (>97%) avec un niveau faible d'impuretés permettant leur utilisation dans des expérimentations biologiques. Les effets vasorelaxants des RSNO ainsi que l'implication des enzymes ont été évalués. Nos résultats montrent que la GGT et la PDI sont capables de dénitroser in vitro le GSNO. Le modèle ex vivo d'anneau aortique isolé de rat Wistar nous a permis de démontrer que l'effet vasorelaxant de GSNO (CE50=3,2±0,5.10-7 M) est dépendant de l'endothélium et de l'activité de la GGT et de la PDI. Concernant la BUC(NO)2, ce dinitrosothiol est catabolisé in vitro par la PDI, est un vasorelaxant plus puissant que la plupart des RSNO (CE50=2,2±0,2.10-8 M) et met en jeu l'activité de la PDI vasculaire. Nos travaux ont conduit à une meilleure compréhension des mécanismes enzymatiques impliqués dans les effets vasculaires des RSNO, ce qui permettra d'optimiser le choix de la meilleure RSNO à utiliser dans une finalité thérapeutique

The aim of our work was to evaluate the enzymatic pathways involved in the release of nitric oxide and in the vasorelaxant effect of S-nitrosothiols (RSNO). We were interested in two enzymes: the gamma-glutamyltransferase (GGT) and the protein disulfide isomerase (PDI), because they play an important role in RSNO denitrosation. Two RSNO were studied: S-nitrosoglutathione (GSNO), an endogenous mononitrosothiol, and S,S'-dinitrosobucillamine (BUC(NO)2), a new dinitrosothiol. We synthesized RSNO and we structurally characterized these products. The resulting data are consistent with the expected structure. Our products have a high purity (>97%) and a limited amount of impurities allowing their suitable use in biological experiments. The vasorelaxant effects of RSNO and the involvement of GGT and PDI were evaluated. The results indicate that purified GGT and PDI denitrosate GSNO in vitro. Furthermore, we demonstrated by using an ex vivo model consisting in an aortic ring isolated from Wistar rat that the vasorelaxant effect of GSNO (EC50=3,2±0,5.10-7 M) was dependent on the endothelium and GGT and PDI activities. As concerns BUC(NO)2, this dinitrosothiol catabolized in vitro by PDI, is more potent (EC50=2,2±0,2.10-8 M) than the most of nitrosothiols described in the literature. This vasorelaxation effect was dependent on PDI activity. In conclusion, our data led to a better understanding of the enzymatic mechanisms involved in the vascular effects of RSNO, which will permit, in physiopathological context, to optimize the choice of the best RSNO for use in a therapeutic purpose, L'objectif de notre travail a consisté en l'étude des mécanismes enzymatiques impliqués dans la libération de l'oxyde nitrique à partir des S-nitrosothiols (RSNO) et dans leurs effets vasorelaxants. Notre intérêt porte sur deux enzymes : la gamma-glutamyltransférase (GGT) et la protéine disulfure isomérase (PDI) car elles jouent un rôle important dans la dénitrosation des RSNO. Nous avons choisi d'étudier la dénitrosation de deux RSNO : le S-nitrosoglutathion (GSNO), un mononitrosothiol endogène et la S,S'-dinitrosobucillamine (BUC(NO)2), un nouveau dinitrosothiol. Nous avons synthétisé ces RSNO et nous avons vérifié la nature du produit obtenu par une caractérisation physico-chimique complète. Les analyses ont montré que ces RSNO présentent une pureté élevée (>97%) avec un niveau faible d'impuretés permettant leur utilisation dans des expérimentations biologiques. Les effets vasorelaxants des RSNO ainsi que l'implication des enzymes ont été évalués. Nos résultats montrent que la GGT et la PDI sont capables de dénitroser in vitro le GSNO. Le modèle ex vivo d'anneau aortique isolé de rat Wistar nous a permis de démontrer que l'effet vasorelaxant de GSNO (CE50=3,2±0,5.10-7 M) est dépendant de l'endothélium et de l'activité de la GGT et de la PDI. Concernant la BUC(NO)2, ce dinitrosothiol est catabolisé in vitro par la PDI, est un vasorelaxant plus puissant que la plupart des RSNO (CE50=2,2±0,2.10-8 M) et met en jeu l'activité de la PDI vasculaire. Nos travaux ont conduit à une meilleure compréhension des mécanismes enzymatiques impliqués dans les effets vasculaires des RSNO, ce qui permettra d'optimiser le choix de la meilleure RSNO à utiliser dans une finalité thérapeutique

Background: A chemometric class modeling strategy (unequal dispersed classes [UNEQ]) is applied for the first time to evaluate harmful alcohol drinking within large population screening programs, in comparison with traditional strategies of data interpretation. Five inexpensive indirect biomarkers (aspartate aminotransferase, alanine aminotransferase, γ-glutamyltransferase, mean corpuscular volume and carbohydrate-deficient transferrin) were determined in blood samples from 423 patients, classified as low-risk or harmful drinkers, according to their ethanol consumption. Results: The multivariate UNEQ approach remarkably improves the diagnostic performances of indirect biomarkers in harmful drinking evaluation, leading to reliable decision rules, with few doubtful classifications to be reviewed through complex confirmation procedures. Conclusion: This UNEQ model represents an innovative general approach for clinical evaluation that efficiently extracts the information content present in each biomarker to provide a new synthetic multivariate parameter, to be directly used in diagnostic protocols.

OBJECTIVE Nonalcoholic fatty liver disease (NAFLD) coexists with insulin resistance (IR), but it is uncertain whether NAFLD and IR contribute independently to atherosclerosis. We tested whether fatty liver, IR, and metabolic syndrome (MetS) features (waist, glucose, triglyceride, HDL cholesterol [HDL-C], and blood pressure) were associated with a marker of atherosclerosis (coronary artery calcium [CAC] score > 0), independently of cardiovascular risk factors and cardiovascular disease (CVD). RESEARCH DESIGN AND METHODS Data were analyzed from a South Korean occupational cohort of 10,153 people who all received ultrasound measurements of fatty liver and a cardiac computed tomography CAC score. IR was defined by homeostasis model assessment of IR (HOMA-IR) >= 75th percentile. Odds ratios (ORs) (95% CIs) for the presence of a CAC score > 0 were estimated using logistic regression. RESULTS There were 915 people with a CAC score > 0. MetS features were increased (glucose, blood pressure, triglyceride, and waist) or decreased (HDL-C) among people with a CAC score > 0 (all comparisons against CAC score 0, 55% had fatty liver and 33.7% were insulin resistant. Fatty liver (OR 1.21 [95% CI 1.01-1.45]; P = 0.04) and HOMA-IR (1.10 [1.02-1.18]; P = 0.02) were associated with CAC score > 0, independently of all MetS features, conventional cardiovascular risk factors, and prior evidence of CVD. The presence of IR and fatty liver combined was associated with CAC score > 0 (1.53 [1.20-1.95]; P = 0.001). CONCLUSIONS Fatty liver and HOMA-IR are both associated with a CAC score > 0 (independently of each other), features of MetS, conventional cardiovascular risk factors, and existing CVD.

Background: Parenteral nutrition-associated liver dysfunction can be progressive and irreversible, particularly in children and patients with long-term treatment. This study has assessed the incidence of abnormal liver function tests in hospitalized adults during short term parenteral nutrition (PN) and has investigated risk factors for developing alterations of each parameter. Methods: A prospective cohort study of parenteral nutrition treated patients with preserved liver function at baseline. Variables examined included nutritional and clinical data and laboratory parameters. Determinations were performed before starting PN and weekly until liver function test alteration was observed. Risk factors were investigated by four stepwise forward logistical regressions. Results: Eighty patients were included, 57.5% had liver function test alterations. PN mean duration was 15.9 (8-54) days. Mean days with PN and additional enteral/ oral nutrition were 1.5 (0-20). The following associations were found: gamma-glutamyl-transferase increased with soybean lipid intake and absolute diet; alkaline phosphatase increased with septic shock; alanine transaminase increased with septic shock, hyperglycemia and elevated creatinine; total bilirubin increased with septic shock, absolute diet, low prealbumin and glucose, and high creatinine. Conclusions: The incidence of altered liver function tests is high in adult hospitalized patients treated with short-term PN. However, the effect of nutritional factors in this alteration is low. Oral/enteral nutrition and reduction of soybean lipid supply can reduce increases in some liver function tests such as gamma-glutamyl-transferase and total bilirubin. The high association between all liver function tests and clinical systemic-hypermetabolic variables suggest the importance of specific nutritional strategies for this condition. Introducción: La alteración hepática asociada a la nutrición parenteral (NP) puede ser progresiva e irreversible particularmente en niños y en tratamientos de larga duración. El objetivo de este estudio es establecer la incidencia de las alteraciones de los parámetros hepáticos en pacientes adultos hospitalizados en tratamiento con NP y estudiar los factores de riesgo asociados al desarrollo de las alteraciones de cada uno de los parámetros hepáticos. Métodos: Estudio prospectivo de cohortes de los pacientes tratados con NP con función hepática normal al inicio del tratamiento. Se estudiaron parámetros clínicos, nutricionales y analíticos. Las determinaciones se hicieron antes de iniciar la nutrición y semanalmente hasta que se detectó la alteración de algún parámetro hepático. Los factores de riesgo asociados a la alteración hepática se estudiaron con 4 regresiones logísticas. Resultados: Se incluyeron 80 pacientes y 57,5% mostraron alteraciones hepáticas. La media de duración de la NP fue 15,9 días (8-54) y la media de días con nutrición enteral u oral concomitantes fue de 1,5 (0-20). Se encontraron las siguientes asociaciones: la gamma-glutamil-transferasa aumentaba con la cantidad de lípidos de soja administrados y los días en dieta absoluta; la fosfatasa alcalina con el shock séptico, la alanina-aminotransferasa con el shock séptico, la hiperglucemia y los valores elevados de creatinina; la bilirrubina total con el shock séptico, la dieta absoluta, valores bajos de prealbúmina y glucosa; y valores altos de creatinina. Conclusiones: La incidencia de alteraciones de los parámetros hepáticos es elevada en pacientes adultos hospitalizados tratados con NP, aunque el efecto de los factores nutricionales en esta alteración es bajo. La nutrición oral/enteral y la reducción de los lípidos en forma de soja pueden reducir el aumento de algunos parámetros hepáticos como la gamma-glutamiltransferasa y la bilirrubina total. La gran asociación entre todos los parámetros hepáticos y las variables sistémicas indicadoras de hiper-metabolismo apuntan a la importancia de las estrategias nutricionales específicas en esta situación.

Background: Parenteral nutrition-associated liver dysfunction can be progressive and irreversible, particularly in children and patients with long-term treatment. This study has assessed the incidence of abnormal liver function tests in hospitalized adults during short term parenteral nutrition (PN) and has investigated risk factors for developing alterations of each parameter. Methods: A prospective cohort study of parenteral nutrition treated patients with preserved liver function at baseline. Variables examined included nutritional and clinical data and laboratory parameters. Determinations were performed before starting PN and weekly until liver function test alteration was observed. Risk factors were investigated by four stepwise forward logistical regressions. Results: Eighty patients were included, 57.5% had liver function test alterations. PN mean duration was 15.9 (8-54) days. Mean days with PN and additional enteral/ oral nutrition were 1.5 (0-20). The following associations were found: gamma-glutamyl-transferase increased with soybean lipid intake and absolute diet; alkaline phosphatase increased with septic shock; alanine transaminase increased with septic shock, hyperglycemia and elevated creatinine; total bilirubin increased with septic shock, absolute diet, low prealbumin and glucose, and high creatinine. Conclusions: The incidence of altered liver function tests is high in adult hospitalized patients treated with short-term PN. However, the effect of nutritional factors in this alteration is low. Oral/enteral nutrition and reduction of soybean lipid supply can reduce increases in some liver function tests such as gamma-glutamyl-transferase and total bilirubin. The high association between all liver function tests and clinical systemic-hypermetabolic variables suggest the importance of specific nutritional strategies for this condition.

Background: Liver function tests might predict the risk of type 2 diabetes. An independent study evaluating utility of these markers compared with an existing prediction model is yet lacking. Methods and Findings: We performed a case-cohort study, including random subcohort (6.5%) from 38,379 participants with 924 incident diabetes cases (the Dutch contribution to the European Prospective Investigation Into Cancer and Nutrition, EPIC-NL, the Netherlands), and another population-based cohort study including 7,952 participants with 503 incident cases (the Prevention of Renal and Vascular End-stage Disease, PREVEND, Groningen, the Netherlands). We examined predictive value of combination of the Liver function tests (gamma-glutamyltransferase, alanine aminotransferase, aspartate aminotransferase and albumin) above validated models for 7.5-year risk of diabetes (the Cooperative Health Research in the Region of Augsburg, the KORA study). Basic model includes age, sex, BMI, smoking, hypertension and parental diabetes. Clinical models additionally include glucose and uric acid (model1) and HbA1c (model2). In both studies, addition of Liver function tests to the basic model improved the prediction (C-statistic by~0.020; NRI by~9.0%; P

OBJECTIVE The pathophysiological mechanisms to explain the association between risk of type 2 diabetes and elevated concentrations of γ-glutamyltransferase (GGT) and alanineaminotransferase (ALT) remain poorly characterized. We explored the association of liver enzymes with peripheral and hepatic insulin resistance, insulin secretion, insulin clearance, and glucagon concentration. RESEARCH DESIGN AND METHODS We studied 1,309 nondiabetic individuals from the Relationship between Insulin Sensitivity and Cardiovascular disease (RISC) study; all had a euglycemic-hyperinsulinemic clamp and an oral glucose tolerance test (OGTT) with assessment of insulin secretion and hepatic insulin extraction. The hepatic insulin resistance index was calculated in 393 individuals. RESULTS In both men and women, plasma concentrations of GGT and ALT were inversely related with insulin sensitivity (M/I) (all P < 0.01). Likewise, the hepatic insulin resistance index was positively correlated with both GGT (r = 0.37, P < 0.0001, men; r = 0.36, P < 0.0001, women) and ALT (r = 0.25, P = 0.0005, men; r = 0.18, P = 0.01, women). These associations persisted in multivariable models. Increased GGT and ALT were significantly associated with higher insulin secretion rates and with both reduced endogenous clearance of insulin and hepatic insulin extraction during the OGTT (P = 0.0005 in men; P = 0.003 in women). Plasma fasting glucagon levels increased over ALT quartiles (men, quartile 4 vs. quartile 1 11.2 ± 5.1 vs. 9.3 ± 3.8 pmol/L, respectively, P = 0.0002; women, 9.0 ± 4.3 vs. 7.6 ± 3.1, P = 0.001). CONCLUSIONS In healthy individuals, increased GGT and ALT were biomarkers of both systemic and hepatic insulin resistance with concomitant increased insulin secretion and decreased hepatic insulin clearance. The novel finding of a positive correlation between ALT and fasting glucagon level concentrations warrants confirmation in type 2 diabetes.

OBJECTIVE: To investigate whether the elevated liver enzymes gamma-glutamyltransferase (GGT), glutamate-pyruvate transaminase (GPT), glutamate-oxalacetate transaminase (GOT) and alkaline phosphatase (AP) and non-alcoholic fatty liver disease (NAFLD) respectively are independently associated with pre-diabetic states, namely impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) or known and newly diagnosed diabetes (NDD), in men and women from the general German population. METHODS: The study was based on 3009 subjects (1556 females, 1453 males) aged 32 to 81 years who participated in the KORA-F4-Study in 2006/2008 in Augsburg, Southern Germany. All non-diabetic participants underwent an oral glucose tolerance test to assess disturbances in glucose metabolism. NAFLD was estimated by liver enzyme concentrations and the Bedogni Fatty Liver Index (FLI). RESULTS: 229 participants (7.6%) reported known diabetes, 106 had NDD (3.5%), 107 (3.6%) had IFG, 309 (10.3%) had IGT, 69 (2.3%) were affected with both metabolic disorders (IFG/IGT) and 74 (2.5%) could not be classified. GGT and GPT were significantly elevated in persons with pre-diabetes and diabetes (GGT in diabetic persons OR = 1.76, [1.47-2.09], in IFG OR = 1.79 [1.50-2.13], GPT in diabetic persons OR = 1.51, [1.30-1.74], in NDD OR = 1.77 [1.52-2.06]), GOT and AP only inconsistently in some pre-diabetes groups. The effects were sharpened in models using an increase of two or three out of three enzymes as an estimate of fatty liver and especially in models using the FLI. Overall frequency of NAFLD applying the index was 39.8% (women: 27.3% and men: 53.2%). In participants with fatty liver disease, the OR for NDD adjusted for sex and age was 8.48 [5.13-14.00], 6.70 [3.74-12.01] for combined IFG and IGT and 4.78 [3.47-6.59] for known diabetes respectively. CONCLUSIONS: Elevated GGT and GPT-values as well as estimates of fatty liver disease are significantly associated with pre-diabetes and diabetes and thus very useful first indicators of a disturbed glucose metabolism.

Cardiovascular disease (CVD) is a leading cause of mortality in renal transplant recipients (RTRs). Metabolic syndrome (MS) is highly prevalent in RTRs. Nonalcoholic fatty liver disease (NAFLD) is considered the hepatic component of MS. We investigated associations of NAFLD markers with MS and mortality. RTRs were investigated between 2001 and 2003. NAFLD markers, alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT) and alkaline phosphatase (AP) were measured. Bone and nonbone fractions of AP were also determined. Death was recorded until August 2007. Six hundred and two RTRs were studied (age 52 +/- 12 years, 55% men). At baseline 388 RTRs had MS. Prevalence of MS was positively associated with liver enzymes. During follow-up for 5.3[4.5-5.7] years, 95 recipients died (49 cardiovascular). In univariate Cox regression analyses, GGT (HR = 1.43[1.21-1.69], p

Background and aims: To investigate the effect of moderate alcohol consumption on lipoprotein-associated phospholipase A2 activity, markers of inflammation and oxidative stress and whether these effects are modified by BMI. Methods and results: Eleven lean (BMI: 18.5-25 kg/m2) and 9 overweight (BMI > 27 kg/m2) men participated in a randomized controlled crossover trial. After consuming 3 cans of beer (40 g ethanol) or alcohol-free beer daily during 3 weeks, fasting blood samples were taken. HDL cholesterol increased by 18.2% (p < 0.001) after beer compared to alcohol-free beer, while LDL cholesterol decreased by 7.8% (p = 0.008). Lipoprotein-associated phospholipase A2 activity was not different (p = 0.23) between beer (47.5 ± 0.8) and alcohol-free beer (48.9 ± 0.8). High-sensitive C-reactive protein was unaffected, but urinary isoprostanes tended to increase (p = 0.09) after beer (114.0 ± 6.9) compared to alcohol-free beer (96.9 ± 6.5). An interaction between BMI and treatment (p < 0.05) on liver enzymes was observed, indicating an increase of liver enzymes after moderate alcohol consumption in overweight men only. Conclusion: Despite profound effects on HDL and LDL cholesterol, moderate alcohol consumption did not affect lipoprotein-associated phospholipase A2 activity. Liver enzymes increased after alcohol consumption in overweight men only, suggesting a less favorable response to moderate alcohol consumption in overweight people.

Background: There are only limited data obtained under well controlled conditions on the effects of moderate drinking on markers of alcohol use disorders. The aim of this study was to investigate the effects of moderate intake of different alcoholic beverages on these markers, including carbohydrate-deficient transferrin (CDT), sialic acid (SA), and the liver enzymes γ-glutamyltransferase, aspartate aminotransferase, and alanine aminotransferase. Methods: Eleven apparently healthy, nonsmoking middle-aged men were included in a 12-week randomized, diet-controlled crossover trial according to a 4 x 4 Latin-square design. Changes in CDT, SA, γ-glutamyltransferase, aspartate aminotransferase, and alanine aminotransferase were analyzed after 3 weeks of daily intake of four glasses (40 g of alcohol) of red wine, beer, spirits (Dutch gin), or water (control). Results: After 3 weeks' daily consumption of red wine, a significant decrease of serum CDT concentration was observed compared with water consumption. There was no effect of any alcoholic beverage on the other outcome measures. Conclusions: Daily consumption of 40 g of alcohol from different types of alcoholic beverages with dinner did not affect SA or liver enzymes. Further investigations to explore the mechanisms for the red wine-induced decreases of CDT, including changes in iron metabolism, are clearly needed.

Non disponible/Not available, Le stress oxydant est induit par le déséquilibre de la balance anti/pro-oxydante. Il est incriminé dans différentes pathologies (maladies neurodégénératives, rhumatoïdes, athérosclérose, vieillissement accéléré...), en tant que facteur de genèse ou phénomène associé. Bien que plusieurs systèmes oxydatifs aient été proposés comme médiateurs possibles des dommages dans ces états pathologiques, l'origine de l'oxydation et le mécanisme oxydatif n'ont pas encore été complètement élucidé. Les enzymes cytochromes P450 (P450)s, qui utilisent l'oxygène pour oxyder leurs substrats, sont une source importante de formation des espèces réactives de l'oxygène (ERO). Le cytochrome P450 2E1 (CYP2E1) se caractérise par une production d'ERO plus importante que les autres isoformes de P450s et est facilement induit par les xénobiotiques. Même si beaucoup d'études ont montré le rôle des P450s dans le métabolisme des composés endogènes et des xénobiotiques, peu d'études évaluent la capacité des P450s à oxyder les protéines et à réguler le système antioxydant. C'est pourquoi nous avons étudié les modifications de la protéine CYP2E1, de son activité en réponse aux xénobiotiques, et les cibles cellulaires d'ERO produits par les P450s, apolipoprotéine E (apoE) et gamma-glutamyltranspeptidase (CGT)...

Non disponible / Not available, La y-glutamyl transferase (GG1) est une enzyme clé dans le métabolisme du giutathion (GSH),mais malgré son importance physiologique, les mécanismes de régulation de la GGT humaine sont très malconnus à cause de la complexité de son organisation génomique.Le premier objectif de notre travail était l'étude de la régulation du gène l (seul gène codant pour une protéine active) dans différentes lignées cellulaires. Nous avons montré qu'en réponse au TP A, aubutyrate de sodium, ou au TNFa, les modulations globales des 3 messagers issus du gène l (ARNm IA, IB eIc) reflètent la modulation de l'activité GGT. Cependant ces 3 ARNm sont régulés de manière indépendante et spécifique de la lignée considérée. Ces résultats montrent que les 3 ARNm issus du gène l sont probab1ement transcrits à partir de promoteurs indépendants, régulés différemment selon le modèlecellulaire. Nous avons ensuite étudié la régulation du promoteur B (dirigeant la transcription de l'ARNm IB)de la GGT humaine (seul promoteur décrit à l'heure actuelle) et nous avons montré que ce promoteur est induit par le TP A dans 2 lignées cellulaires. Cette induction passe par la fixation du facteur AP1 (composé d'une sous unité cJun au moins) à l'un des 3 sites AP1 proximaux étudiés. Nous avons également montré que 1es séquences situées en amont de ces sites AP1 sont impliquées dans la modulation de l'induction par le TP A et dans sa spécificité cellulaire.Enfin, nous avons localisé, cloné et partiellement caractérisé un nouveau promoteur sur le gène l humain de la GGT : celui qui dirige la transciption des ARNm Ic. Le second objectif de notre travail était de déterminer le rôle de la GGT dans la réponse cellulaire au cisplatine (CDDP) et au carboplatine, couramment utilisés en chimiothérapie. Nous avons montré qu'une des réponses rapides des cellules HeLa à un traitement par l'un de ces agents résulte en une induction du taux de GSH intracellulaire et de l'activité GGT ce qui laisse supposer un rôle important pour la GGT dans la réponse aux dérivés du platine. Nous avons utilisé une lignée HeLa isogénique, transfectée par l'ADNc de la GGT humaine (HeLa-GG1) qui expriment l'enzyme à un niveau 10 fois supérieur à celui de la lignée parentale HeLa. Cette lignée a permis de montrer que les cellules HeLa-GGT possèdent une résistance accrue aux CDDP et au carboplatine lorsque du GSH extracellulaire est fourni aux cellules. Dansle cas du carboplatine, la résistance est directement corrélée au taux de GSH intracellulaire. En revanche, le contenu intracellulaire en GSH ne semble pas être un facteur déterminant pour la réponse au CDDP dans notre modèle. En effet, les cellules HeLa cultivées dans un milieu complet possèdent un fort taux de GSHb intracellulaire et lorsque le milieu de culture est appauvri en cystéine elles perdent plus de 80 % de leur pool (indépendamment de leur activité GGT). Or, la cytotoxicité du CDDP est comparable dans ces deux conditions de culture. Afin d'expliquer la plus grande résistance des cellules HeLa-GGT au CDDP lorsque du GSH extracellulaire est fourni, nous avons étudié le catabolisme du GSH par la GGT au niveau extracellulaire. Nous avons alors montré que le CDDP est capable d'interagir avec le produit de dégradation du GSH par la GGT : la CysGly. Ce composé est d'ailleurs plus réactif que le GSH et il forme des adduits avec le CDDP 10 fois plus rapidement que le GSH. Nous avons également été capables de détecter cet adduit dans 1e milieu extracellulaire des cellules HeLa-GGT incubées en présence de CDDP et de GSH. Nous suggérons que ce mécanisme dépendant de la GGT pourrait être impliqué dans la résistance des ceUules au CDDP en diminuant la quantité de CDDP disponible et/ou sa toxicité.

Non disponible/Not available, Le stress oxydant traduit soit une production exagérée d'espèces réactives de l'oxygène, soit une défaillance des systèmes de défenses antioxydantes. Ce syndrome est de, plus en plus incriminé dans des pathologies très variées comme les maladies neurodégénératives, cardio-vasculaires et le cancer. La y-glutamyltranspeptidase (GGT) intervient dans ce syndrome d'une manière ambivalente, par ses effets anti et pro-oxydant, les deux étant corrélés à la capacité de cette enzyme de métaboliser le glutathion (GSH). En effet, en initiant le métabolisme du GSH, la GGT fournit les précurseurs nécessaires pour la synthèse intracellulaire du GSH. De ce fait, la GGT est considérée comme faisant partie de la défense antioxydante. D'autre part, à l'extérieur de la cellule, le métabolite cystéinylglycine (CysGly), formé par l'action catalytique de la GGT sur le GSH, peut initier, en présence de fer, une cascade de réaction produisant des espèces radicalaires. L'objectif principal de cette étude est d'étudier le rôle pro-oxydant de cette enzyme et ses conséquences sur les constituants et les fonctions cellulaires. Dans la première partie de ce travail, nous avons démontré par dosagespectrofluorimétrique sur des modèles cellulaires ou en présence de GGT purifiée une production GGT-dépendante d'espèces réactives de l'oxygène (ERO). Ces ERO oxydent leslipides membranaires et les lipoprotéines de basse densité (LDL). Le Trolox C, antioxydant qui piège les radicaux hydroxyles, réduit partiellement l'oxydation GGT -dépendante des LDL. Cependant, dans nos conditions expérimentales, les ERG produites par le système GGT/GSH/Fe3+ n'endommagent pas l'ADN cellulaire. Le rôle pro-oxydant de la GGT -rel, une autre enzyme capable d'initier le catabolisme du GSH, a été également mis en évidence. En effet, en présence de GSH et de fer, la GGT -rel présente dans les membranes de cellules en culture est responsable d'une formation d'ERO et d'une peroxydation lipidique. La seconde partie met en évidence l'implication de la GGT dans l'apoptose. En effet, le système générateur d'ERO, GGT/GSH/Fe3+, induit la mort cellulaire par apoptose dans notre modèle cellulaire comme le montrent le marquage à l'annexine- V, l'analyse du cycle cellulaire et la mesure de l'activité caspase-3. L'intensité de la réponse dépend essentiellement de la concentration de GSH dans le milieu. De plus, nous avons démontré que l'acivicine, inhibiteur largement utilisé de la GGT, possède par lui-même un pouvoir pro-apoptotique en dehors de toute inhibition de la GGT et par conséquent ne peut pas être utilisé dans les études concernant le rôle de la GGT dans le phénomène de mort cellulaire programmée. Enfin, la troisième partie a été consacrée à l'étude du rôle pro-oxydant de la GGT in vivo. Nos résultats ont montré une corrélation entre l'activité GGT et le degré de peroxydation lipidique dans le plasma de patients supposés sains. Le globule rouge (GR) pourrait être une des cibles de cette oxydation GGT -dépendante dans le sang circulant. En effet, le système GGT/GSH/Fe3+ oxyde les membranes de globule rouge. Cette oxydation dépend du niveau d'activité GGT et de la concentration de GSH et de fer. Elle se traduit par une hémolyse et une baisse de la déformabilité érythrocytaire, partiellement inhibées par le Trolox C. De plus, une corrélation existe entre l'activité GGT plasmatique et l'index de déformabilité du GR dans une population de sujets supposés sains.

Two protocols of quantification of enzymatic activity in milk were finalized. The first was the measurement of lactoperoxydase (LPO) activity. The second was the measurement of[gamma]-glutamyl transpeptidase ([gamma]-GT) activity. They incorporated a clarification step of the reaction mixture that allowed a direct spectrophotometric measurement from which an appreciable time-saving. Milk heated in the range of 50 to 80°C showed that the thermo-sensitivity of LPO and [gamma]-GT renders these enzymes useful to estimate the efficiency or the severity of pasteurization. Results obtained with these protocols on various milks presented a good correlation (R[exponent 2] >= 0,97) with those obtained with reference protocols. These new protocols could be applied on cheese too. Fourier transform infrared spectroscopy was selected for the study of changes in protein spatial conformation. When heating milk at 80°C, protein b-sheet and a helix proportions decrease slightly. Proportion of turns and random coils increase. Turn proportion could serve as thermal indicator. These study will have to be confirmed by using a sufficient number of milks for which thermal historic is known., Deux protocoles de dosage d'activité de la lactoperoxydase (LPO) et de la [gamma]-glutamyl transpeptidase ([gamma]-GT) dans le lait ont été mis au point. Ils comprennent une étape de transparisation permettant une lecture spectrophotométriques directe d'où un gain de temps appréciable. Des laits chauffés entre 50 et 80°C ont montré que la LPO et la [gamma]-GT ont une thermo-sensibilité permettant leur utilisation pour l'appréciation de l'efficacité ou de la sévérité de la pasteurisation. Les résultats obtenus avec ces protocoles sur différents laits sont bien corrélés (R[exposant 2] >= 0,97) avec ceux obtenus avec des protocoles de référence. Ces nouveaux protocoles sont également applicables sur des fromages. La spectroscopie infrarouge à transformée de Fourier a été choisie pour l'étude des modifications de conformation spatiale des protéines. Lors du chauffage du lait à 80°C, les taux de feuillet b et d'hélice a diminuent légèrement. Les taux de coudes et de structures désordonnées augmentent. Les structures type coudes pourrait servir d'indicateur thermique du lait. Ces mesures réalisées devront être renouvelées sur des laits dont on connaît l'historique thermique.

Non disponible / Not available

Biochemical, histopathological and cell culture evaluations compared the nephrotoxicity of cefazolin with that of gentamicin. New Zealand rabbits were dosed with 250 mg cefazolin/animal im twice daily, 3 mg gentamicin/kg im twice daily, or 0.9% NaCl solution for 10 d. The rabbits in drug-treated groups had necrosis of proximal kidney tubules and elevated urinary-gamma glutamyl transferase (uGGT) levels. The results of the histopathological examinations, uGGT analyses and effects in cell culture indicated the nephrotoxicities of both antibiotics were similar.

The catabolism of glutathione and glutathion conjugates is initiated by the cleavage of the y-glutamyl moiety by the only enzyme y-glutamyltransferase (GGT E C 3.2.2.2). This heterodimeric glycoprotein arise From the proteolytic cleavage of a precursor and it is localized on the outer face of the plasma membrane. Important variations in GGT activity are known to occur during development, carcinogenesis and cell differentiation. It is commonly admitted that GGT participates in the active transport of aminoacids, but also in other biochemical pathways such as detoxification or inflammatory responses by processing GSH-conjugated electrophiles and leukotrienes. GGT genomic organization is well established in rat and mouse. A unique gene encodes several mRNA species that differ in the il' 5' untranslated regions. These mRNAs are transcribed under the control of several tissue-specific promoters which have been described here., Le catabolisme du glutathion et de ses dérivés débute par le clivage du groupement y-glutamyle par la seule enzyme apte à cette réaction, la gamma-glutamyltransférase (GGT E C 3.2.2.2). Cette glycoprotéine hétérodimérique est issue du clivage protéolytique d'un précurseur et est localisée à la surface externe des membres plasmiques. L'activité de cette enzyme varie fortement au cours du développement, de la cancérogenèse et de la différenciation cellulaire. Il est admis qu'elle participe au transport actif de certains acides aminés ainsi qu'aux processus de détoxication et aux réactions inflammatoires en métabolisant les conjugués électrophiles du glutathion et les leucotriènes. L'organisation génomique de la GGT est bien définie chez le rat ou la souris. Un seul gène murin code pour des ARNm différant uniquement par leurs régions 5' non traduites. Ces ARNm sont sous le contrôle de différents promoteurs d'ores et déjà décrits. [...]

Not available, Non disponible