gamma-Glutamyltransferase dependent generation of reactive oxygen species from a glutathione/transferrin system

Gamma-glutamyl transpeptidase and indirect bilirubin may participate in systemic inflammation of patients with psoriatic arthritis

BACKGROUND

Previous studies have suggested that systemic metabolic abnormalities are closely related to psoriatic arthritis (PsA). Gamma-glutamyl transpeptidase (GGT) and indirect bilirubin (IBIL), two essential active substances in hepatic metabolism that have been demonstrated as an oxidative and anti-oxidative factor respectively, have been proved to be involved in oxidative stress damage and inflammation in several human diseases. However, their role in PsA remains unclear.

METHODS

In this retrospective comparative cohort study, a case group of 68 PsA patients and a control group of 73 healthy volunteers from the Third Hospital of Hebei Medical University were enrolled. Serum GGT, IBIL, GGT/IBIL ratio and C-reactive protein (CRP), a well applied bio-marker of systemic inflammatory in PsA, were compared between the two groups. Furthermore, the relationship of GGT, IBIL and GGT/IBIL with CRP were explored in PsA patients. Finally, the patients were divided into high inflammation group and low inflammation group according to the median value of CRP. Multivariate logistic regression analyses were used for the association of systemic inflammation level with GGT, IBIL and GGT/IBIL.

RESULTS

Compared with healthy controls, PsA patients exhibited significantly higher serum GGT, GGT/IBIL, and CRP levels and lower IBIL levels. Serum GGT and GGT/IBIL were positively correlated with CRP, whereas IBIL were negatively correlated with CRP. Binary logistic regression analysis revealed that serum GGT was a risk factor for high CRP in PsA, whereas IBIL was a protective factor. Furthermore, GGT/IBIL was a better indicator of high CRP condition in PsA patients than either GGT or IBIL alone, as determined by the receiver operating characteristic curves.

CONCLUSION

GGT and IBIL may participate in the pathogenesis of PsA. Additionally, GGT, IBIL and the balance of the two may reflect systemic inflammation mediated by oxidative stress events related to metabolic abnormalities to a certain extent.

Ketosis Suppression and Ageing (KetoSAge): The Effects of Suppressing Ketosis in Long Term Keto-Adapted Non-Athletic Females

Most studies on ketosis have focused on short-term effects, male athletes, or weight loss. Hereby, we studied the effects of short-term ketosis suppression in healthy women on long-standing ketosis. Ten lean (BMI 20.5 ± 1.4), metabolically healthy, pre-menopausal women (age 32.3 ± 8.9) maintaining nutritional ketosis (NK) for > 1 year (3.9 years ± 2.3) underwent three 21-day phases: nutritional ketosis (NK; P1), suppressed ketosis (SuK; P2), and returned to NK (P3). Adherence to each phase was confirmed with daily capillary D-beta-hydroxybutyrate (BHB) tests (P1 = 1.9 ± 0.7; P2 = 0.1 ± 0.1; and P3 = 1.9 ± 0.6 pmol/L). Ageing biomarkers and anthropometrics were evaluated at the end of each phase. Ketosis suppression significantly increased: insulin, 1.78-fold from 33.60 (± 8.63) to 59.80 (± 14.69) pmol/L (p = 0.0002); IGF1, 1.83-fold from 149.30 (± 32.96) to 273.40 (± 85.66) µg/L (p = 0.0045); glucose, 1.17-fold from 78.6 (± 9.5) to 92.2 (± 10.6) mg/dL (p = 0.0088); respiratory quotient (RQ), 1.09-fold 0.66 (± 0.05) to 0.72 (± 0.06; p = 0.0427); and PAI-1, 13.34 (± 6.85) to 16.69 (± 6.26) ng/mL (p = 0.0428). VEGF, EGF, and monocyte chemotactic protein also significantly increased, indicating a pro-inflammatory shift. Sustained ketosis showed no adverse health effects, and may mitigate hyperinsulinemia without impairing metabolic flexibility in metabolically healthy women.

Affinity purification, identification, and biochemical characterization of Gamma-glutamyl transpeptidase, a membrane anchored enzyme of Gigantocotyle explanatum

Gamma-glutamyl transpeptidase is an enzyme that facilitates the transfer of glutamyl groups from glutamyl peptides to other peptides or water. Additionally, it also participates in important processes such as amino acid transport, cellular redox control, drug detoxification, apoptosis, and DNA fragmentation in a various organism. In the present study, GGT activity in Gigantocotyle explanatum was examined in order to characterize the enzyme in the helminth system. GGT is isolated using membrane solubilization and purified through affinity column chromatography (Con-A Sepharose column). Km and Vmax values, as well as the optimal pH, optimal temperature, and incubation period, are also determined using enzyme kinetics. The hetero-dimeric property of the enzyme is demonstrated by the purified GGT, which yielded two subunits of 65.5 and 55 kDa. The optimal pH and temperature are found to be 8.0 and 37 °C, respectively. While assessing the optimal incubation time of the enzyme, it was observed that the purified GGT not only retained its functional integrity up to 15 min but also reflected considerable thermostability at higher temperatures, by retaining 78% and 25% of its initial activities at 50 °C and 60 °C, respectively. One millimolar concentration of 6-Diazo-5-Oxo Nor-isoleucine (DON), a specific inhibitor of GGT, completely abolished GGT activity. These results suggest that GGT in these worms is a catalytically active enzyme with distinguishing characteristics that can be used for further study to comprehend its function in amphistome biology and in host-parasite relationships, especially since the potential therapeutic candidacy of the GGT enzyme has already been indicated in these groups of organisms.

Can Gamma-glutamyl Transferase Predict Unhealthy Metabolic Phenotypes Among Healthcare Workers in Azar Cohort Study?

Background: Although various studies have assessed the correlation between gamma-glutamyl transferase (GGT) and cardiometabolic risk factors in obesity, no research has differentiated among metabolically-healthy obese (MHO) and metabolically unhealthy obese (MUHO), metabolically-healthy lean (MHL), and metabolically-unhealthy lean (MUHL). Objectives: Accordingly, this study evaluated the correlation between GGT and cardiometabolic phenotypes among healthcare workers. Methods: In this study, there were anthropometric measurements as well as the measurements of fasting blood sugar (FBS), GGT, cholesterol, triglyceride (TG), high lipoprotein density (HDL), and blood pressure in 1458 healthcare workers enrolled in the Azar Cohort Study. Metabolic syndrome (MetS) was defined according to the National Cholesterol Education Program Adult Treatment Panel III (ATP III). Accordingly, the participants were divided into four cardiometabolic phenotypes. Results: In this cross-sectional study, there was a significant difference in the prevalence of cardiometabolic phenotypes regarding the GGT tertiles (P ≤ 0.001). The highest prevalence of MHO was observed in the third GGT tertile. The mean waist circumference, TG, FBS, HDL, and systolic and diastolic blood pressure levels increased in the MHO, MUHO, and MHL groups in a dose dependent manner with an increase in the GGT tertiles (P < 0.05). In comparing the highest and lowest GGT tertile, the risk of MHO and MUHO increased by 2.84 (95%CI 2.01 - 4.01) and 9.12 (95%CI 5.54 - 15), respectively. However, the correlation between the GGT tertile and MUHL did not reveal a similar trend. The ROC curve shows the cutoff value of 18.5 U/L for GGT, which allowed us to distinguish between the MUHO and MHO individuals. Conclusions: The findings revealed that GGT can indicate the risk of MetS as such, it can be used to detect at-risk MHO individuals and administer proper interventions.

Liver enzymes and risk of ocular motor cranial nerve palsy: a nationwide population-based study

This study aimed to assess the associations between liver enzymes including γ-glutamyl transferase (GGT) and the development of ocular motor cranial nerve palsy (CNP) using the National Sample Cohort database from Korea's National Health Insurance Service. We analyzed data from 4,233,273 medical screening examinees aged 20 years or more in 2009. Study participants were followed up until December 31, 2018. A Cox proportional hazard regression analysis was performed for quartiles of liver enzymes to determine the linkage between each value and ocular motor CNP using quartile 1 as a reference after adjusting for potential confounders. A total of 5,807 (0.14%) patients developed ocular motor CNP during the follow-up period of 8.22 ± 0.94 years. The incidence of ocular motor CNP gradually increased as the GGT levels increased. The highest quartile of the GGT group had hazard ratio (HR) of 1.245 (95% confidence interval [CI], 1.136-1.365). Regarding alanine aminotransferase (ALT), the highest quartile of the ALT group had HR of 1.141 (95% CI, 1.049-1.241). However, the incidence of ocular motor CNP did not gradually increase as the ALT levels increased. The coexistence of the increased level of GGT, metabolic syndrome, and obesity showed a stronger association with ocular motor CNP development (HR, 1.331; 95% CI, 1.173, 1.511) compared to having a single factor or two factors. In conclusion, our population-based cohort study demonstrated a significant association between serum GGT level and the incidence of ocular motor CNP, suggesting that GGT could be a new clinical marker for predicting the occurrence of ocular motor CNP.

Remote Ischemic Preconditioning Reduces Marathon-Induced Oxidative Stress and Decreases Liver and Heart Injury Markers in the Serum

Clinical studies continue to provide evidence of organ protection by remote ischemic preconditioning (RIPC). However, there is lack of insight into impact of RIPC on exercise-induce changes in human organs' function. We here aimed to elucidate the effects of 10-day RIPC training on marathon-induced changes in the levels of serum markers of oxidative stress, and liver and heart damage. The study involved 18 male amateur runners taking part in a marathon. RIPC training was performed in the course of four cycles, by inflating and deflating a blood pressure cuff at 5-min intervals (RIPC group, n=10); the control group underwent sham training (n=8). The effects of RIPC on levels of oxidative stress, and liver and heart damage markers were investigated at rest after 10 consecutive days of training and after the marathon run. The 10-day RIPC training decreased the serum resting levels of C-reactive protein (CRP), alanine transaminase (ALT), γ-glutamyl transpeptidase (GGT), and malondialdehyde (MDA). After the marathon run, creatinine kinase MB (CK-MB), lactate dehydrogenase (LDH), cardiac troponin level (cTn), aspartate aminotransferase (AST), alkaline phosphatase (ALP), ALT, total bilirubin (BIL-T), and MDA levels were increased and arterial ketone body ratio (AKBR) levels were decreased in all participants. The changes were significantly diminished in the RIPC group compared with the control group. The GGT activity remained constant in the RIPC group but significantly increased in the control group after the marathon run. In conclusion, the study provides evidence for a protective effect of RIPC against liver and heart damage induced by strenuous exercise, such as the marathon.

Fluorescent probes for visualizing ROS-associated proteins in disease

Abnormal expression of proteins, including catalytic and expression dysfunction, is directly related to the development of various diseases in living organisms. Reactive oxygen species (ROS) could regulate protein expression by redox modification or cellular signal pathway and thus influence the development of disease. Determining the expression level and activity of these ROS-associated proteins is of considerable importance in early-stage disease diagnosis and the identification of new drug targets. Fluorescence imaging technology has emerged as a powerful tool for specific in situ imaging of target proteins by virtue of its non-invasiveness, high sensitivity and good spatiotemporal resolution. In this review, we summarize advances made in the past decade for the design of fluorescent probes that have contributed to tracking ROS-associated proteins in disease. We envision that this review will attract significant attention from a wide range of researchers in their utilization of fluorescent probes for in situ investigation of pathological processes synergistically regulated by both ROS and proteins.

Serum gamma-glutamyltransferase, oxidized LDL and mortality in the elderly

BACKGROUND

Serum gamma-glutamyltransferase (GGT) is a liver enzyme involved in the metabolism of glutathione (GSH), a major antioxidant in humans. GGT is a risk factor for mortality in young and middle-aged individuals but this association has been poorly investigated in the elderly.

METHODS

We studied the relationship between GGT and all-cause mortality and tested whether oxidized low-density lipoproteins (oxLDL) modify this association in a cohort of 1038 elderly individuals.

RESULTS

During the observation time (median 9 years), 401 individuals died. In a Cox regression model adjusting for potential confounders, GGT was an independent risk factor for all-cause mortality [HR (20U/L increase in serum GGT): 1.11, 95% CI 1.02-1.21, P = 0.02]. Furthermore, increasing levels of oxLDL amplified the risk excess for all-cause mortality associated with GGT (P for the effect modification = 0.003).

CONCLUSIONS

In the elderly, serum GGT is an independent risk factor for all-cause mortality and circulating oxLDL amplify the magnitude of this association.

Synergistic ROS-Associated Antimicrobial Activity of Silver Nanoparticles and Gentamicin Against Staphylococcus epidermidis

Introduction

Increasing bacteria resistance to antibiotics is a major problem of healthcare system. There is a need for solutions that broaden the spectrum of bactericidal agents improving the efficacy of commonly used antibiotics. One of the promising directions of search are silver nanoparticles (obtained by different methods and displaying diversified physical and chemical properties), and their combination with antibiotics.

Purpose

In this study, we tested the role of reactive oxygen species in the mechanism of synergistic antibacterial activity of gentamicin and Tween-stabilized silver nanoparticles against gentamicin-resistant clinical strains of Staphylococcus epidermidis.

Methods

Synergistic bactericidal activity of gentamicin and silver nanoparticles stabilized with non-ionic detergent (Tween 80) was tested by the checkerboard titration method on microtiter plates. Detection of reactive oxygen species was based on the chemiluminescence of luminol.

Results

Hydrophilic non-ionic surface functionalization of silver nanoparticles enabled the existence of non-aggregated active nanoparticles in a complex bacterial culture medium. Tween-stabilized silver nanoparticles in combination with gentamicin exhibited bactericidal activity against multidrug-resistant biofilm forming clinical strains of Staphylococcus epidermidis. A synergistic effect significantly decreased the minimal inhibitory concentration of gentamicin (the antibiotic with numerous undesirable effects). Gentamicin significantly enhanced the generation of reactive oxygen species by silver nanoparticles.

Conclusion

Generation of reactive oxygen species by Tween-coated metallic silver nanoparticles was significantly enhanced by gentamicin, confirming the hypothesis of oxidative-associated mechanism of the synergistic antibacterial effect of the gentamicin-silver nanoparticles complex.

Transcriptional profiling and therapeutic targeting of oxidative stress in neuroinflammation

Oxidative stress is a central part of innate-immune induced neurodegeneration. However, the transcriptomic landscape of the central nervous system (CNS) innate immune cells contributing to oxidative stress is unknown, and therapies to target their neurotoxic functions are not widely available. Here, we provide the oxidative stress innate immune cell atlas in neuroinflammatory disease, and report the discovery of new druggable pathways. Transcriptional profiling of oxidative stress-producing CNS innate immune cells (Tox-seq) identified a core oxidative stress gene signature coupled to coagulation and glutathione pathway genes shared between a microglia cluster and infiltrating macrophages. Tox-seq followed by a microglia high-throughput screen (HTS) and oxidative stress gene network analysis, identified the glutathione regulating compound acivicin with potent therapeutic effects decreasing oxidative stress and axonal damage in chronic and relapsing multiple sclerosis (MS) models. Thus, oxidative stress transcriptomics identified neurotoxic CNS innate immune populations and may enable the discovery of selective neuroprotective strategies.

Application of CT radiomics in prediction of early recurrence in hepatocellular carcinoma

PURPOSE

To appraise the ability of the computed tomography (CT) radiomics signature for prediction of early recurrence (ER) in patients with hepatocellular carcinoma (HCC).

METHODS

A set of 325 HCC patients were enrolled in this retrospective study and the whole dataset was divided into 2 cohorts, including "training set" (225 patients) and "test set" (100 patients). All patients who underwent partial hepatectomy were followed up at least within 1 year. 656 Radiomics features were extracted from arterial-phase and portal venous-phase CT images. Lasso regression model was used for data dimension reduction, feature selection, and radiomics signature building. Univariate analysis was used to identify clinical and radiomics significant features. Models (radiomics signature, clinical model, and combined model) were evaluated by area under the curve (AUC) of receiver operating characteristic curve. The models' performances for prediction of ER were assessed.

RESULTS

The radiomics signature was built by 14 selected radiomics features and was significantly associated with ER (P < 0.001); the AUCs of the "train set" and the "test set" were 0.818 (95% CI 0.760-0.865) and 0.719 (95% CI 0.621-0.805), respectively. The tumor size, tumor capsule, and γ-glutamyl transferase (GGT) were significantly associated with ER in the clinical model (P < 0.05). The combined model showed incremental prognostic value, with the AUCs of "training dataset" and "test dataset" were 0.846 (95% CI 0.792-0.890) and 0.737 (95% CI 0.640-0.820), respectively. The radiomics signature, tumor size, and the level of GGT were independent predictors of ER (P < 0.05).

CONCLUSIONS

The CT radiomics signature can be conveniently used to predict the ER in patient with HCC. The combined model performed better for prediction of ER than radiomics signature or clinical model.

Glutathione: Antioxidant Properties Dedicated to Nanotechnologies

Which scientist has never heard of glutathione (GSH)? This well-known low-molecular-weight tripeptide is perhaps the most famous natural antioxidant. However, the interest in GSH should not be restricted to its redox properties. This multidisciplinary review aims to bring out some lesser-known aspects of GSH, for example, as an emerging tool in nanotechnologies to achieve targeted drug delivery. After recalling the biochemistry of GSH, including its metabolism pathways and redox properties, its involvement in cellular redox homeostasis and signaling is described. Analytical methods for the dosage and localization of GSH or glutathiolated proteins are also covered. Finally, the various therapeutic strategies to replenish GSH stocks are discussed, in parallel with its use as an addressing molecule in drug delivery.

Quillaja saponaria bark saponin protects Wistar rats against ferrous sulphate-induced oxidative and inflammatory liver damage

CONTEXT

Saponins from different sources are historically reported in Chinese medicine to possess many beneficial effects. However, insufficient experimental data are available regarding the hepatoprotective potential of Quillaja bark saponin.

OBJECTIVE

The protective effect of Quillaja saponaria Molina (Quillajaceae) bark triterpenoid saponin against iron-induced hepatotoxicity is compared to the standard N-acetylcysteine in adult male Wistar rats.

MATERIALS AND METHODS

Animals were divided into (six) groups, namely a normal control, an N-acetylcysteine control (300 mg/kg/day, p.o., 10 days), a saponin control (100 mg/kg/day, p.o., for 10 days), a hepatotoxicity control (two doses of ferrous sulphate, 30 mg/kg/day each, i.p., on 9th and 10th day), an N-acetylcysteine plus ferrous sulphate (standard treatment) and a saponin plus ferrous sulphate (test treatment) group. Hepatocyte integrity loss markers (serum ALT, AST, ALP, GGT and LDH), oxidative stress markers (hepatic MDA, GSH and NOx), dyslipidaemic markers (serum TC and TG) and hepatocyte functioning markers (serum bilirubin and albumin) were assessed.

RESULTS

Quillaja bark saponin decreased iron-induced elevation of ALT (reaching 57% of hepatotoxicity control), AST (66%), ALP (76%), GGT (60%), LDH (54%), MDA (65%), NOx (77%), TC (70%), TG (54%), and total (54%), direct (54%) and indirect (54%) bilirubin, coupled with increased GSH (219%) and albumin (159%) levels. Histopathological study strongly supported biochemical estimations, while immunohistochemical study showed marked effect on eNOS and iNOS expression.

CONCLUSIONS

Quillaja bark saponin has a good hepatoprotective effect. Amelioration of oxidative stress and suppression of NOS expression, with resultant maintenance of hepatocyte integrity and functioning, may explain this beneficial effect.

Association of serum gamma-glutamyltransferase and C-reactive proteins with neuromyelitis optica and multiple sclerosis

BACKGROUND

Many studies have demonstrated that serum gamma glutamyltransferase (GGT) within normal range might be an early marker of oxidative stress. However the role of GGT in neuromyelitis optica (NMO) and multiple sclerosis (MS) is unknown.

METHODS

We assessed the correlations among GGT and C-reactive protein (CRP) levels, as well as clinical characteristics of NMO and MS. Serum GGT and CRP levels were measured in 106 NMO patients, 87 MS patients, 79 patients with non-inflammatory neurological diseases (Parkinson disease) and 80 healthy controls (HC). Clinical parameters, blood-brain barrier (BBB) index and Delpech index of MS and NMO were also investigated.

RESULTS

We found that NMO patients had higher serum GGT and CRP levels within their normal ranges compared to MS, PD, healthy controls. NMO patients exhibited significantly higher EDSS scores than MS patients. The BBB index in NMO patients was significantly higher than that in MS patients. Significant correlations existed between serum GGT and CRP levels and EDSS scores, BBB index in NMO and MS patients.

CONCLUSION

Elevated GGT and CRP levels within their normal ranges in NMO and MS may be associated with inflammatory response, oxidative stress and BBB disturbance in the diseases. Further study into the underlying pathophysiology of this relationship is warranted.

Oxidized LDL, Gamma-Glutamyltransferase and Adverse Outcomes in Older Adults

OBJECTIVES

Gamma-glutamyltransferase (GGT) is a biomarker of liver disease and oxidative stress which was associated with all-cause and cardiovascular (CV) mortality in the general population and in patients with high risk conditions. This study aims at assessing whether oxLDL modifies the relationship between GGT, all-cause, and CV mortality in elderly individuals from the general population.

DESIGN

Observational longitudinal study.

SETTING

Population-based cohort of older individuals (>65 years) free of liver disease.

PARTICIPANTS

One thousand and thirty-eight individuals from the Invecchiare in Chianti (InCHIANTI) study.

MEASUREMENTS

Serum GGT level, oxidized low-density lipoprotein (oxLDL), CV comorbidities, all-cause and CV mortality.

RESULTS

The median age of the study population (n = 1,038) was 74 years (inter-quartile range: 69-79), 152 individuals (15%) had past CV events. During a median follow-up of 9 years, 401 individuals died, 168 of them (42%) for CV causes. In adjusted analyses, GGT predicted all-cause mortality (HR for 20 U/L increase in serum GGT: 1.11, 95% CI: 1.02-1.21, P = .02) and CV mortality (HR: 1.17, 95% CI: 1.03-1.33; P = .02). Furthermore, in an analysis for interaction circulating oxLDL amplified the effect of GGT on all-cause mortality (P = .003).

CONCLUSION

Circulating oxLDL amplifies the effect of GGT on mortality in the elderly. The mechanism for this association remains unknown and requires further research, including studying the potential role of GGT in oxidative stress. These results are consistent with the hypothesis of a causal role of GGT in the CV morbidity and mortality in older individuals and indicate that oxLDL plays a crucial role in the interpretation of the link between GGT and the risk of adverse clinical events in this population.

Oxidative balance score and serum γ-glutamyltransferase level among Korean adults: a nationwide population-based study

PURPOSE

The oxidative balance score (OBS) comprises dietary and non-dietary lifestyle pro-oxidants and antioxidants. Elevated serum γ-glutamyltransferase (GGT) level has currently emerged as a biomarker of oxidative stress. In this study, we examined whether OBS was inversely associated with serum GGT level and whether OBS could be a useful marker to predict GGT among Korean adults.

METHODS

This cross-sectional study was based on data obtained from the 2010 and 2011 Korea National Health and Nutrition Examination Survey. 2087 men and 2071 women were included in final analysis. The OBS was divided into five equal interval categories, and GGT was dichotomized into low and high using its sex-specific median value. Multiple logistic regression analysis was conducted to assess the association between OBS categories and high GGT.

RESULTS

Compared with the lowest OBS category as reference, the multivariable adjusted ORs (95% CIs) for the highest OBS category of men and women were 0.05 (0.01-0.19) and 0.27 (0.09-0.78), respectively (p for trend <0.01).

CONCLUSION

A higher OBS that indicates a predominance of antioxidant over pro-oxidant exposure was strongly inversely associated with GGT level among Korean adults.

Oral glutathione supplementation drastically reduces Helicobacter-induced gastric pathologies

Helicobacter (H.) suis causes gastric pathologies in both pigs and humans. Very little is known on the metabolism of this bacterium and its impact on the host. In this study, we have revealed the importance of the glutamate-generating metabolism, as shown by a complete depletion of glutamine (Gln) in the medium during H. suis culture. Besides Gln, H. suis can also convert glutathione (GSH) to glutamate, and both reactions are catalyzed by the H. suis γ-glutamyltranspeptidase (GGT). Both for H. pylori and H. suis, it has been hypothesized that the degradation of Gln and GSH may lead to a deficiency for the host, possibly initiating or promoting several pathologies. Therefore the in vivo effect of oral supplementation with Gln and GSH was assessed. Oral supplementation with Gln was shown to temper H. suis induced gastritis and epithelial (hyper)proliferation in Mongolian gerbils. Astonishingly, supplementation of the feed with GSH, another GGT substrate, resulted in inflammation and epithelial proliferation levels returning to baseline levels of uninfected controls. This indicates that Gln and GSH supplementation may help reducing tissue damage caused by Helicobacter infection in both humans and pigs, highlighting their potential as a supportive therapy during and after Helicobacter eradication therapy.

Clinical significance of serum bilirubin and gamma-glutamyltransferase levels on coronary atherosclerosis assessed by multidetector computed tomography

BACKGROUND AND AIMS

Low bilirubin and high gamma-glutamyltransferase (GGT), which are endogenous markers of oxidative stress, confer a higher risk of cardiovascular disease (CVD). We investigated associations between serum concentrations of bilirubin, GGT and coronary atherosclerosis.

METHODS AND RESULTS

A cross-sectional analysis was performed on 1520 subjects who underwent multidetector computed tomography scans. Coronary atherosclerosis was assessed by coronary artery calcium score (CACS) and obstructive coronary artery disease (OCAD), was defined as the presence of coronary artery stenosis of ≥50%. Total bilirubin (TB) level was negatively correlated with CACS and coronary stenosis whereas GGT level was positively correlated with CACS in men. However, there was no correlation between TB, GGT levels and either CACS or coronary artery stenosis in women. In a multivariate-adjusted model, TB level was inversely associated with a CACS > 100 [odds ratio (OR) per log standard deviation (SD), 0.67; 95% confidence interval (CI), 0.52-0.87], and OCAD (OR per log SD, 0.77; 95% CI, 0.62-0.95) in men. By contrast, GGT level was positively associated with a CACS > 100 (OR per log SD, 1.35; 95% CI, 1.05-1.73) but not with OCAD. Adding TB and GGT to the conventional risk factors increased predictive accuracy for CACS > 100 (net reclassification improvement index [NRI] = 13.1%, P = 0.026; integrated discrimination index [IDI] = 0.024, P = 0.001) and for OCAD (NRI = 12.6%, P = 0.026; IDI = 0.010, P = 0.013).

CONCLUSIONS

Low TB and high GGT levels were concomitantly associated with coronary atherosclerosis in Korean men. Future studies are needed to elucidate the causal associations of TB and GGT with CVD.

Liver function parameters in hip fracture patients: relations to age, adipokines, comorbidities and outcomes

AIM

To asses liver markers in older patients with hip fracture (HF) in relation to age, comorbidities, metabolic characteristics and short-term outcomes.

METHODS

In 294 patients with HF (mean age 82.0±7.9 years, 72.1% women) serum alanine aminotransferase (ALT), gammaglutamyltransferase (GGT), alkaline phosphatase (ALP), albumin, bilirubin, 25(OH)vitaminD, PTH, calcium, phosphate, magnesium, adiponectin, leptin, resistin, thyroid function and cardiac troponin I were measured.

RESULTS

Elevated ALT, GGT, ALP or bilirubin levels on admission were observed in 1.7%-9.9% of patients. With age GGT, ALT and leptin decrease, while PTH and adiponectin concentrations increase. Higher GGT (>30 U/L, median level) was associated with coronary artery disease (CAD), diabetes mellitus (DM), and alcohol overuse; lower ALT (≤20 U/L, median level) with dementia; total bilirubin>20 μmol/L with CAD and alcohol overuse; and albumin>33 g/L with CAD. Multivariate adjusted regression analyses revealed ALT, ALP, adiponectin, alcohol overuse and DM as independent and significant determinants of GGT (as continuous or categorical variable); GGT for each other liver marker; and PTH for adiponectin. The risk of prolonged hospital stay (>20 days) was about two times higher in patients with GGT>30 U/L or adiponectin>17.14 ng/L (median level) and 4.7 times higher if both conditions coexisted. The risk of in-hospital death was 3 times higher if albumin was <33 g/L.

CONCLUSIONS

In older HF patients liver markers even within the normal range are associated with age-related disorders and outcomes. Adiponectin (but not 25(OH)vitaminD, PTH, leptin or resistin) is an independent contributor to higher GGT. Serum GGT and albumin predict prolonged hospital stay and in-hospital death, respectively. A unifying hypothesis of the findings presented.

Serum gamma - glutamyltransferase is associated with albuminuria: a population-based study

Background

Serum γ - glutamyltransferase (GGT) is implicated in the pathogenesis of endothelial dysfunction and atherosclerosis. Albuminuria is a marker of endothelial damage and correlated with structural and functional integrity of the vasculature. Our objective was to evaluate the association between serum GGT level and prevalence of albuminuria in a Chinese population.

Materials and Methods

We conducted a population-based cross-sectional study in 9,702 subjects aged 40 years or older. Increased urinary albumin excretion was defined according to the urinary albumin-to-creatinine ratio (ACR) ranges greater or equal than 30 mg/g. Low-grade albuminuria was defined according to the highest quartile of ACR in participants without increased urinary albumin excretion.

Results

The prevalence of low-grade albuminuria and increased urinary albumin excretion were respectively 23.4% and 6.6% in this population and gradually increased across the sex-specific serum GGT quartiles (all P for trend <0.05). In logistic regression analysis, compared with subjects in the lowest quartile of serum GGT level, the adjusted odds ratios (ORs) in the highest quartile was 1.22 [95% confidence interval (CI), 1.04–1.43] for low-grade albuminuria and 1.55 (95% CI, 1.18–2.04) for increased urinary albumin excretion. In subgroup analysis, significant relationship of serum GGT level with both low-grade albuminuria and increased urinary albumin excretion were detected in women, younger subjects, overweight subjects and in those with hypertension or glomerular filtration rate greater than 90 (all P <0.05).

Conclusion

Serum GGT level is associated with urinary albumin excretion in middle-aged and elderly Chinese.

Protective effects of hesperidin on oxidative stress, dyslipidaemia and histological changes in iron-induced hepatic and renal toxicity in rats

The present study was to evaluate the protective role of hesperidin (HDN) against iron-induced hepatic and renal toxicity in rats. Administration of iron (30 mg/kg body weight) intraperitoneally for 10 days, the levels of serum hepatic markers, renal functional markers, lipid profile, lipid peroxidation markers and iron concentration in blood were significantly (p < 0.05) increased. The toxic effect of iron was also indicated by significant (p < 0.05) decrease in the levels of plasma, liver and kidney of enzymatic and non-enzymatic antioxidants. Administration of hesperidin at different doses (20, 40 and 80 mg/kg body weight) significantly (p < 0.05) reversed the levels of serum hepatic markers, renal functional markers, lipid profile, lipid peroxidation markers, restored the levels of hepatic, renal enzymatic antioxidants and non-enzymatic antioxidants with decrease in iron concentration in blood. Hesperidin at a dose of 80 mg/kg body weight exhibits significant protection on hepatic and renal when compared with other two doses (20 and 40 mg/kg body weight). All these changes were corroborating by histological observations of liver and kidney. This study demonstrated the protective role of hesperidin in reducing toxic effects of iron in experimental rats.

Glutathione S-conjugates as prodrugs to target drug-resistant tumors

Living organisms are continuously exposed to xenobiotics. The major phase of enzymatic detoxification in many species is the conjugation of activated xenobiotics to reduced glutathione (GSH) catalyzed by the glutathione-S-transferase (GST). It has been reported that some compounds, once transformed into glutathione S-conjugates, enter the mercapturic acid pathway whose end products are highly reactive and toxic for the cell responsible for their production. The cytotoxicity of these GSH conjugates depends essentially on GST and gamma-glutamyl transferases (γGT), the enzymes which initiate the mercapturic acid synthesis pathway. Numerous studies support the view that the expression of GST and γGT in cancer cells represents an important factor in the appearance of a more aggressive and resistant phenotype. High levels of tumor GST and γGT expression were employed to selectively target tumor with GST- or γGT-activated drugs. This strategy, explored over the last two decades, has recently been successful using GST-activated nitrogen mustard (TLK286) and γGT-activated arsenic-based (GSAO and Darinaparsin) prodrugs confirming the potential of GSH-conjugates as anticancer drugs.

Clinical characteristics, outcome, and risk factors for early and late intrahepatic recurrence of female patients after curative resection of hepatocellular carcinoma

BACKGROUND

There have been progressive increases in both the incidence and death rates of female patients with hepatocellular carcinoma (HCC). Our objective was to investigate the clinicopathologic characteristics and prognostic factors influencing the recurrence and survival of female patients with HCC.

METHODS

We performed a retrospective analysis of 459 consecutive female and 2,936 male patients with HCC who underwent curative resection. Multivariate competing risks analyses with Bonferroni correction were used to evaluate independent prognostic factors.

RESULTS

Female patients had a better overall survival rate (P = .001) than male patients, but a survival benefit was only observed in female patients with tumor-node-metastasis stage I diseases compared with male patients of the same stage (P = .023). Female patients less often had multiple tumors, vascular invasion, and larger tumors. Although female patients had a greater prevalence of increased serum alpha-fetoprotein (AFP), AFP and tumor number had prognostic significance only for male but not for female patients. The incidence of recurrence in female patients was not different than male patients (P = .130). Vascular invasion and serum γ-glutamyl transpeptidase level were independent risk factors for early recurrence of female patients, whereas AFP and γ-glutamyl transpeptidase level were independent risk factors for late recurrence. After curative treatment for recurrence, female patients still had a better overall survival than male patients (P = .025).

CONCLUSION

Female patients had a less invasive tumor phenotype and different prognostic factors from male patients. AFP had no prognostic value in female patients. Estrogen may have a protective effect against early- but not late-stage HCC. Female patients have a better outcome after curative resection of recurrent HCC.

The higher plasma malondialdehyde concentrations are determined by metabolic syndrome-related glucolipotoxicity

This study aimed to elucidate the determinants of higher plasma malondialdehyde (MDA) in free-living adults. In a cross-sectional study we evaluated 148 free-living subjects (54 ± 11 years, 78% women) at high risk for or with metabolic syndrome (MetS). They were assessed by anthropometry and body composition, dietary intake, and clinical and laboratorial analysis. The analysis of plasma MDA was performed by HPLC, and concentration values were used to provide four groups according to percentile distribution. Subjects with higher plasma MDA showed higher prevalence of MetS and higher values of waist circumference (WC), glucose, triglycerides (TG), γ-glutamyltransferase (γ-GT), and higher energy intake. Multiadjusted logistic regression analysis identified as determinants of higher plasma MDA the altered values of WC and γ-GT followed by hypertriglyceridemia, hyperglycemia, insulin resistance, higher dietary sugar-intake, and presence of MetS. In conclusion, the glucolipotoxic state predisposed by the presence of MetS seems to be the major determinant of higher plasma MDA concentrations.

Antioxidant intervention attenuates oxidative stress in children and teenagers with Down syndrome

We previously demonstrated that systemic oxidative stress is present in Down syndrome (DS) patients. In the present study we investigated the antioxidant status in the peripheral blood of DS children and teenagers comparing such status before and after an antioxidant supplementation. Oxidative stress biomarkers were evaluated in the blood of DS patients (n=21) before and after a daily antioxidant intervention (vitamin E 400mg, C 500 mg) during 6 months. Healthy children (n=18) without DS were recruited as control group. The activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST), gamma-glutamyltransferase (GGT), glucose-6-phosphate dehydrogenase (G6PD) and myeloperoxidase (MPO), as well as the contents of reduced glutathione (GSH), uric acid, vitamin E, thiobarbituric acid reactive substances (TBARS), and protein carbonyls (PC) were measured. Before the antioxidant therapy, DS patients presented decreased GST activity and GSH depletion; elevated SOD, CAT, GR, GGT and MPO activities; increased uric acid levels; while GPx and G6PD activities as well as vitamin E and TBARS levels were unaltered. After the antioxidant supplementation, SOD, CAT, GPx, GR, GGT and MPO activities were downregulated, while TBARS contents were strongly decreased in DS. Also, the antioxidant therapy did not change G6PD and GST activities as well as uric acid and PC levels, while it significantly increased GSH and vitamin E levels in DS patients. Our results clearly demonstrate that the antioxidant intervention with vitamins E and C attenuated the systemic oxidative damage present in DS patients.

The association between liver enzymes and risk of type 2 diabetes: the Namwon study

BACKGROUND

We examined the association between liver enzymes and development of type 2 diabetes in a general Korean population.

METHODS

A total of 10,667 subjects (4,201 males and 6,466 females) aged 45 to 74 years participated in a baseline examination between 2004 and 2007. Among the subjects, 8,157 (3,231 males and 4,926 females) underwent follow-up examination from 2007 to 2011, for a median follow-up period of 4.2 years. Type 2 diabetes was defined as intake of anti-diabetic agents, insulin treatment, fasting glucose concentration of more than 126 mg/dl, or hemoglobin A1c of more than 6.5% at re-examination. Associations of liver enzymes with incidence of type 2 diabetes were analyzed using logistic regression models.

RESULTS

During the follow-up period, 548 subjects (235 males, 313 females) developed type 2 diabetes. After adjusting for comprehensive diabetes risk factor, the risk of type 2 diabetes was significantly higher in the highest alanine aminotransferase (ALT) quartile than in the lowest quartile (odds ratio (OR): 1.95, 95% confidence interval (CI): 1.18-3.21 in males; OR: 1.49, 95% CI: 1.03-2.16 in females). Similar results were observed for gamma-glutamyltransferase (GGT) quartiles, but in the fully adjusted analysis, the OR for the highest versus lowest quartiles was significant only for females (OR: 1.58, 95% CI: 0.95-2.63 in males; OR: 1.85, 95% CI: 1.23-2.79 in females).

CONCLUSIONS

Our results suggest that serum ALT concentrations were independently associated with type 2 diabetes in both sexes, and that GGT was also independently associated but only in females.

An association between serum γ-glutamyltransferase and proteinuria in drinkers and non-drinkers: a Japanese nationwide cross-sectional survey

BACKGROUND

The association between alcohol consumption and chronic kidney disease (CKD), characterized by reduced glomerular filtration rate and proteinuria, is controversial. Recent studies suggest that serum γ-glutamyltransferase (GGT) level, a conventional marker of excessive alcohol consumption, predicts the CKD incidence. Little information is available on the difference in the clinical impact of alcohol consumption and GGT on proteinuria.

METHODS

The present cross-sectional survey included 332,296 Japanese people aged ≥40 years in 2008. To examine the associations of GGT and alcohol consumption with proteinuria, 134,600 men and 197,696 women were classified into 20 categories based on GGT quartiles and alcohol consumption categories, and their prevalence rate ratios (PRR) of proteinuria defined as ≥1+ of dipstick urinary protein were calculated after adjusting for clinically relevant factors.

RESULTS

Prevalence of proteinuria was 7.5 and 3.7 % in men and women, respectively. In both gender an association between alcohol consumption and proteinuria was in a J-shaped fashion with the lowest PRR of mild drinkers with ≤19 g/day of ethanol consumption, whereas an association between serum GGT level and proteinuria was linear. Compared with rare drinkers in the lowest GGT quartile, the subjects in higher GGT quartiles had a higher probability of proteinuria, irrespective of alcohol consumption. An optimal cutoff level of serum GGT was 43.6 and 23.2 IU/L in men and women, respectively.

CONCLUSIONS

The subjects with higher serum GGT level had a higher probability of proteinuria, regardless of alcohol consumption, suggesting that GGT has a clinically greater impact on CKD than alcohol consumption.

New evidence for an association between liver enzymes and pancreatic islet β-cell dysfunction in young obese patients

To explore the relationship between serum liver enzymes and both the glucose tolerance status and insulin secretion in young obese patients. A total of 734 young obese patients (BMI ≥ 25 kg m(-2)) and 231 lean healthy volunteers matched in age (BMI < 23 kg m(-2)) were enrolled in this cross-sectional observational study. The 734 obese patients were subdivided to three groups (OB-NGR, OB-IGR, and OB-DM) according to their glucose tolerance status. FSIVGTT was performed to assess the degree of insulin sensitivity (SI) and islet secretion function (AIRg). The disposition index (DI; product of SI and AIRg) was calculated as an integrated measurement of insulin secretion and insulin action after compensating for insulin resistance. The extent and distribution of hepatic fat infiltration was assessed using the liver/spleen ratio (L/S ratio) with CT scan. ALT and GGT levels in OB-NGR, OB-IGR, and OB-DM groups were significantly increased compared to the normal controls, and were incrementally increased in turn in the three groups, whereas DI decreased at the same time. One standard deviation increment in ALT and GGT increased the risk of β-cell dysfunction after controlling for potential confounders such as sex, age, BMI, waist-hip ratio, and blood pressure. Even after the adjustment of the serum lipid profile and L/S ratio, the odds ratio of ALT remained statistically significant (OR, 1.603; 95 % CI, 1.225-2.096). Serum levels of liver enzymes showed an independent close relationship with insulin secretion capacity. Excluding the impact of a fatty liver, increased ALT and GGT levels indicated a significant association with the attenuation of pancreatic β-cell function. This study provides the possibility that elevated liver enzymes might be treated as simple biomarkers of early insulin secretion deficit in type 2 diabetes, especially in young obese patients.

Helicobacter bilis gamma-glutamyltranspeptidase enhances inflammatory stress response via oxidative stress in colon epithelial cells

Helicobacter bilis (H. bilis) infection is associated with cases of inflammatory bowel Disease, thyphlocolitis, hepatitis and cholecystitis. However, little is known about the bacterial virulence determinants or the molecular mechanisms involved. Recently, H. bilis γ-glutamyltranspeptidase (HBgGT) was shown to be a virulence factor decreasing host cell viability. Bacterial gGTs play a key role in synthesis and degradation of glutathione and enables the bacteria to utilize extracellular glutamine and glutathione as sources of glutamate. gGT-mediated loss of cell viability has so far been linked to DNA damage via oxidative stress, but the signaling cascades involved herein have not been described. In this study, we identified enhanced ROS production induced by HBgGT as a central factor involved in the activation of the oxidative stress response cascades, which finally activate CREB, AP-1 and NF-κB in H. bilis infected colon cancer cells. IL-8, an important pro-inflammatory chemokine that is a common downstream target of these transcription factors, was up-regulated upon H. bilis infection in an HBgGT dependent manner. Moreover, the induction of these signaling responses and inflammatory cytokine production in host cells could be linked to HBgGT-mediated glutamine deprivation. This study implicates for the first time HBgGT as an important regulator of signaling cascades regulating inflammation in H. bilis infected host epithelial cells that could be responsible for induction of inflammatory disorders by the bacterium.

The correlates of urinary albumin to creatinine ratio (ACR) in a high risk Australian aboriginal community

BACKGROUND

Albuminuria marks renal disease and cardiovascular risk. It was estimated to contribute 75% of the risk of all-cause natural death in one Aboriginal group. The urine albumin/creatinine ratio (ACR) is commonly used as an index of albuminuria. This study aims to examine the associations between demographic factors, anthropometric index, blood pressure, lipid-protein measurements and other biomarkers and albuminuria in a cross-sectional study in a high-risk Australian Aboriginal population. The models will be evaluated for albuminuria at or above the microalbuminuria threshold, and at or above the "overt albuminuria" threshold with the potential to distinguish associations they have in common and those that differ.

METHODS

This was a cross-sectional study of 598 adults aged 18-76 years. All participants were grouped into quartiles by age. Logistic regression models were used to explore the correlates of ACR categories.

RESULTS

The significant correlates were systolic blood pressure (SBP), C-reactive protein (CRP), uric acid, diabetes, gamma-glutamyl transferase (GGT) (marginally significant, p=0.054) and serum albumin (negative association) for ACR 17+ (mg/g) for men and 25+ for women. Independent correlates were SBP, uric acid, diabetes, total cholesterol, alanine amino transferase (ALT), Cystatin C and serum albumin (negative association) for overt albuminuria; and SBP, CRP and serum albumin only for microalbuminuria.

CONCLUSIONS

This is the most detailed modelling of pathologic albuminuria in this setting to date. The somewhat variable association with risk factors suggests that microalbuminuria and overt albuminuria might reflect different as well as shared phenomena.

Therapeutic efficacy of silymarin from milk thistle in reducing manganese-induced hepatic damage and apoptosis in rats

Oxidative stress has been proposed as a possible mechanism involved in manganese (Mn) toxicity. Using natural antioxidants against metal-induced hepatotoxicity is a modern approach. The present study investigated the beneficial role of silymarin, a natural flavonoid, in Mn-induced hepatotoxicity focusing on histopathology and biochemical approaches. Male Wistar rats were exposed orally to manganese chloride (20 mg/mL) for 30 days followed by intraperitoneal cotreatment with silymarin (100 mg/kg). Exposure to Mn resulted in a significant elevation of the plasma marker enzyme activities and bilirubin level related to liver dysfunction of reactive oxygen species (ROS) production and hepatic oxidative stress indices. This metal reduced the activities of superoxide dismutase, catalase and glutathione peroxidase and nonenzymatic antioxidant levels such as reduced glutathione, total sulfhydryl groups and vitamin C. In addition, it caused hepatic hemorrhage, cellular degeneration and necrosis of hepatocytes as indicated by liver histopathology and DNA fragmentation studies. Coadministration of silymarin alleviated Mn oxidative damage effects by inhibiting ROS generation. Histological studies also supported the beneficial role of silymarin against Mn-induced hepatic damages. Combining all, results suggested that silymarin could protect hepatic tissues against Mn-induced oxidative stress probably through its antioxidant activity. Therefore, its supplementation could provide a new approach for the reduction in hepatic complication due to Mn poisoning.

Serum gamma-glutamyltransferase levels are inversely related to endothelial function in chronic kidney disease

BACKGROUNDS

Gamma-glutamyltransferase (GGT) is an enzyme responsible for the extracellular catabolism of the antioxidant glutathione and recently implicated in the pathogenesis of atherosclerosis. Endothelial dysfunction is a prodromal feature of atherogenesis. Since oxidative stress is highly present in uremia and causally linked to endothelial dysfunction, we hypothesized that GGT may be a factor implicated in this process.

METHODS

Serum GGT and C-reactive protein (CRP) levels, estimated glomerular filtration rate (eGFR), and 24-h proteinuria were measured in 214 nondiabetic stages 3-5 CKD patients. The endothelium-dependent vasodilatation (FMD) of the brachial artery was assessed by using high-resolution ultrasound. We investigated the relationship between FMD and circulating serum GGT.

RESULTS

Serum GGT levels were negatively associated with FMD (r = -0.41, p < 0.001) and eGFR (r = -0.34, p < 0.001) in univariate analysis. Multivariate regression analysis showed that the association between GGT and FMD persisted after adjustment for age, sex, smoking, renal function (eGFR), inflammation (CRP), proteinuria, and homeostatic model assessment index.

CONCLUSION

Circulating GGT levels significantly associate with endothelial dysfunction, an important early feature of the atherogenic process. GGT might be an early marker of oxidative or other cellular stress that it is possibly directly related to the pathogenesis of endothelial dysfunction.

Lack of a relationship between circulating gamma-glutamyltransferase levels and carotid intima media thickness in hypertensive and diabetic patients

BACKGROUND

By increasing the intracellular prooxidant burden, gamma-glutamyltransferase (GGT) may accelerate atherosclerotic vascular disease. That noxious influence may be reflected by circulating enzyme levels, a correlate of cardiovascular risk factors, and a predictor of incident events. To evaluate this hypothesis, we tested the association between circulating GGT and common carotid intima-media thickness (CIMT), a surrogate index of systemic atherosclerotic involvement, in a large and well-characterized group of patients at risk of cardiovascular disease (CVD).

PATIENTS

This study analyzed 548 patients with hypertension and/or diabetes and a widely prevalent history of CVD. Subjects with known hepatic disease and abnormal GGT values were excluded.

METHODS

CIMT (B-mode ultrasonography) values were the mean of four far-wall measurements at both common carotids. Metabolic syndrome (MetS) was diagnosed according to National Cholesterol Education Program-Adult Treatment Panel III criteria. Due to inherent sex-related differences in GGT levels, the data were analyzed separately in males and females in samples dichotomized by the median.

RESULTS

The age-adjusted CIMT values did not differ by GGT levels in males or females. In contrast, the carotid wall was consistently thicker in patients with a history of CVD and MetS independent of age and concurrent GGT values. In both sexes, GGT was associated with key components of the MetS such as triglycerides, fasting plasma glucose, and body mass index.

CONCLUSION

The data collected in this mixed group of hypertensive and/or diabetic patients with widely prevalent history of CVD do not support the concept of a direct pathophysiological link between GGT levels within reference limits and atherosclerotic involvement.

Consumption of red meat and whole-grain bread in relation to biomarkers of obesity, inflammation, glucose metabolism and oxidative stress

Purpose

To examine the association of red meat and whole-grain bread consumption with plasma levels of biomarkers related to glucose metabolism, oxidative stress, inflammation and obesity.

Methods

Our cross-sectional study was based on 2,198 men and women who were selected as a sub-cohort for an investigation of biological predictors of diabetes and cardiovascular diseases from the European Prospective Investigation into Cancer and Nutrition-Potsdam study. Circulating levels of glycated hemoglobin, adiponectin, hs-CRP, gamma-glutamyltransferase, alanine-aminotransferase, fetuin-A, HDL-cholesterol and triglycerides were measured from random blood samples. Diet and lifestyle data were assessed by questionnaires, and anthropometric data were measured.

Results

After multivariable adjustment, higher consumption of whole-grain bread was significantly (P trend <0.05) associated with lower levels of GGT, ALT and hs-CRP, whereas higher consumption of red meat was significantly associated with higher levels of GGT and hs-CRP when adjusted for potential confounding factors related to lifestyle and diet. Further adjustment for body mass index and waist circumference attenuated the association between red meat and hs-CRP (P = 0.19).

Conclusions

The results of this study suggest that high consumption of whole-grain bread is related to lower levels of GGT, ALT and hs-CRP, whereas high consumption of red meat is associated with higher circulating levels of GGT and hs-CRP.

Serum gamma-glutamyltransferase level is associated with serum superoxide dismutase activity and metabolic syndrome in a Japanese population

BACKGROUND

Serum gamma-glutamyltransferase level has attracted considerable attention as a predictor of various conditions, such as cardiovascular disease and cancer. Although the mechanism that links the serum gamma-glutamyltransferase level to these diseases is not fully understood, one explanation is that gamma-glutamyltransferase may be closely related to oxidative stress. We conducted a large cross-sectional study to evaluate the relationship between serum gamma-glutamyltransferase and oxidative stress.

METHODS

We examined anti-oxidative stress activity and accumulation of oxidative stress in serum obtained from 2907 subjects who underwent a complete health check-up. We used serum total superoxide dismutase activity as an index of anti-oxidative stress activity. Superoxide dismutase is one of the most important intracellular and extracellular defense systems against superoxide, but the relationship between serum superoxide dismutase activity and the serum gamma-glutamyltransferase level is unclear.

RESULTS

The serum gamma-glutamyltransferase level was negatively correlated with serum superoxide dismutase activity, a correlation that was observed even within the normal range. A subgroup analysis stratified by the amount of alcohol consumed also showed a similar correlation. In contrast, the serum gamma-glutamyltransferase level was positively correlated with serum lipid peroxide level, even in the normal range. Furthermore, an increased serum gamma-glutamyltransferase level was significantly associated with the progression of metabolic syndrome and carotid artery intima-media thickness.

CONCLUSIONS

The serum gamma-glutamyltransferase level, even in the normal range, was significantly associated with anti-oxidative stress activity, the accumulation of oxidative stress, metabolic syndrome, and atherosclerosis. Measuring the serum gamma-glutamyltransferase level is simple and inexpensive, and this level can be used as a sensitive marker of oxidative stress and metabolic syndrome.

Relationship between liver function and brain shrinkage in patients with alcohol dependence

BACKGROUND

Oxidative stress has been proposed as one of the mechanisms of alcohol-induced brain shrinkage and alcohol-induced hepatotoxicity. The aim of this study was to assess the correlations between liver function and brain volume (BV) measurements in patients with alcohol dependence.

METHODS

We recruited 124 patients with alcohol dependence and 111 healthy control subjects from National Institute of Health, National Institute on Alcohol Abuse and Alcoholism inpatient alcohol treatment program. Gamma-glutamyl transferase (GGT), aspartate aminotransferase (AST), alanine aminotransferase (ALT), as well as hematocrit (Hct) and albumin were assayed shortly after admission. Magnetic resonance imaging examination was conducted in both groups (after 3-week abstinence in the patient group). We used stepwise linear regression analyses to determine the variables most strongly correlated with brain shrinkage.

RESULTS

Patients with alcohol dependence had lower BV, and greater brain shrinkage as measured by gray matter ratio (GMR), white matter ratio (WMR), brain ratio (BR), and higher cerebrospinal fluid ratio ratio (CSFR) compared with their healthy counterparts. Age and sex were significantly correlated with some BV measurements in both patient and control groups. Body mass index (BMI) was significantly correlated with CSFR, BR, GMR, and WMR; Hct with CSFR and BR; serum GGT level with BV, CSFR, BR, GMR, and WMF in the patient group. No biological variables were correlated with BV indices in the control group. In gender-stratified analysis, age was significantly correlated with brain shrinkage in male patients but not in female patients. Serum GGT level in male and female patients, Hct in male patients, and AST levels in female patients were significantly correlated with brain shrinkage.

CONCLUSIONS

Our results showed that the higher levels of liver function indices, especially GGT, correlated with BV shrinkage as measured using CSFR, BR, GMR, and WMR in patients with alcohol dependence but not in controls. Serum GGT level outweighed aging effect on brain shrinkage in female patients.

Risk factors for development of diabetes mellitus, hypertension and dyslipidemia

We investigated the risk factors for the development of diabetes mellitus, hypertension and dyslipidemia simultaneously in a community-based observational cohort study (n=4304). When hypertension or dyslipidemia was present at baseline, hazard ratio (95% CI) of developing diabetes mellitus at year 5 is 3.014 (2.131-4.264) or 2.112 (1.520-2.936), respectively.

Protective role of sinapic acid against arsenic: induced toxicity in rats

Arsenic compounds are classified as toxicants and human carcinogens. Environmental exposure to arsenic imposes a big health issue worldwide. Sinapic acid is a phenylpropanoid compound and is found in various herbal materials and high-bran cereals. It has been reported that sinapic acid has antioxidant efficacy as metal chelators due to the orientation of functional groups. However, it has not yet been examined in experimental animals. In light of this fact, the purpose of this study was to characterize the protective role of sinapic acid against arsenic induced toxicity in rats. Rats were orally treated with arsenic alone (5mg/kg body weight (bw)/day) plus sinapic acid at different doses (10, 20 and 40mg/kg bw/day) for 30days. Hepatotoxicity was measured by the increased activities of serum hepatospecific enzymes namely aspartate transaminase, alanine transaminase, alkaline phosphatase, gamma glutamyl transferase, lactate dehydrogenase and total bilirubin along with increased elevation of lipid peroxidative markers, thiobarbituric acid reactive substances, lipid hydroperoxides, protein carbonyl content and conjugated dienes. The toxic effect of arsenic was also indicated by significantly decreased activities of enzymatic antioxidants like superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase, glutathione reductase and glucose-6-phosphate dehydrogenase along with non-enzymatic antioxidant like reduced glutathione. Administration of sinapic acid exhibited significant reversal of arsenic induced toxicity in hepatic tissue. The effect at a dose of 40mg/kgbw/day was more pronounced than the other two doses (10 and 20mg/kgbw/day). All these changes were supported by reduction of arsenic concentration and histopathological observations of the liver. These results suggest that sinapic acid has a protective effect over arsenic induced toxicity in rat.

Oxidative stress is associated with liver damage, inflammatory status, and corticosteroid therapy in patients with systemic lupus erythematosus

Oxidative stress exerts an important role on the pathophysiological mechanisms of systemic lupus erythematosus (SLE). This study investigated oxidative stress in patients with SLE and its correlation with disease activity, corticosteroid therapy, and liver function biomarkers. The study included 58 patients with SLE and 105 healthy volunteers. Patients showed oxidative stress increase evaluated by tert-butyl hydroperoxide-initiated chemiluminescence (CL-LOOH), advanced oxidation protein products (AOPP), and nitric oxide metabolites. C-reactive protein (CRP) was associated with CL-LOOH and with AOPP. Aspartate aminotransferase correlated significantly with CL-LOOH and with AOPP. Patients with disease activity showed an inverse significant correlation of daily prednisone doses and CL-LOOH and a direct correlation with total antioxidant capacity. In conclusion, patients with SLE have persistent lipoperoxidation and protein oxidation even with inactive disease or mild disease activity. The significant correlation between oxidative stress and CRP suggests that, despite clinical remission, the persistence of an inflammatory condition favors oxidative stress. Oxidative stress was associated with liver enzymes, and this relationship seems to support the hypothesis of drug-induced oxidative stress with consequent liver injury. In relation to non-active disease, patients with active SLE did not present oxidative stress and antioxidant capacity changes, due to the antioxidant drugs used in SLE treatment, especially prednisone.