Gamma glutamyl transferase

Relationship between gamma-glutamyltransferase and fat mass in a general population of 8–17 years old children. The FLVS II study

AIM

Elevated gamma-glutamyltransferase (GGT) is positively associated with severity of obesity in obese children and with increased BMI and waist circumference in general populations of adults. We aimed to study the relationships between GGT and anthropometric parameters in a general population of children.

METHODS

This cross-sectional study was conducted in 219 boys and 214 girls included in the Fleurbaix Laventie Ville Santé II study. Weight, height, four skinfolds and waist circumference were measured. We compared the means of GGT activity according to gender and Tanner stage, and according to overweight status (IOTF definition) and quartiles of anthropometric parameters. We then calculated partial Pearson correlations by gender between GGT and anthropometric parameters taking age and Tanner stage into account.

RESULTS

GGT activity was higher in boys than in girls as soon as puberty started (P<0.001). The higher difference was observed for Tanner stage III (GGT=10.2 UI/L, CI95% of mean (9.5, 11.1) vs. 7.8 UI/L (7.2, 8.4)). Anthropometric parameters were significantly associated with GGT, particularly waist circumference (r=0.28 in boys; r=0.24 in girls). After an additional adjustment for sum of skinfolds, this correlation disappeared in boys (r=0.06), and was still significant in girls (r=0.19).

CONCLUSION

In a general population of children, overweight and abdominal fat distribution were associated with increased GGT. As some studies have shown that GGT could predict the metabolic syndrome in children and type 2 diabetes in adults, the modest elevation of GGT observed in overweight children may be of pathophysiological importance in the long term.

Obesity and the clinical use of serum GGT activity as a marker of heavy drinking

OBJECTIVE

Gamma-glutamyl transferase (GGT) is a widely used clinical marker of alcohol abuse. However, although obesity may also elevate serum GGT activities, the effects of overweight on the interpretation of GGT testing have remained poorly defined.

MATERIAL AND METHODS

GGT activities from 1147 moderate drinkers and 449 abstainers who were classified according to body mass index (BMI) were compared with those of 208 heavy drinkers admitted for detoxification.

RESULTS

GGT upper normal limits, defined based on normal weight abstainers (men 53 U/L; women 45 U/L) were lower than those based on moderate drinkers (men 68 U/L; women 50 U/L). The relative increases in GGT activities in male moderate drinkers with overweight (54%) or obesity (125%) exceeded the corresponding changes found in women (25% and 75%, respectively). The BMI-dependent variation on the sensitivity of GGT for correctly classifying heavy drinkers ranged from 29% to 67%. The rates of false-positive values in the subgroups from low to high BMI varied from 0% to 27%, respectively.

CONCLUSIONS

The data indicate that the diagnostic value of serum GGT testing could be improved by using reference data derived from databases of abstainers with normal weight or BMI-based categorization of reference ranges.

Increased serum gamma-glutamyl-transpeptidase concentration is associated with nonalcoholic steatosis and not with cholestasis in patients with chronic hepatitis C

BACKGROUND AND AIM

Increased pretreatment gamma-glutamyl-transpeptidase (gammaGT) is common in patients with chronic hepatitis C and with little or no alcohol consumption. The mechanism involved in this phenomenon is unclear, and the aim of this study was to investigate factors associated with increased gammaGT levels, specifically looking at the role of cholestasis that frequently accompanies hepatitis C.

METHODS

Fifty patients with chronic hepatitis C enrolled in two trials of antiviral treatment, 25 with normal and 25 with elevated pretreatment gammaGT levels, were retrospectively selected. In addition to the common liver function and virological tests, other values measured were serum bile acid concentration and composition by gas-chromatography as a sensitive index of cholestasis, and liver biopsy scores for cholestasis and steatosis in addition to siderosis, fibrosis and inflammation.

RESULTS

Total mean serum bile acid concentration was 11.6 +/- 1.4 micromol/L and 8.5 +/- 1.2 micromol/L (not significant) in patients with elevated and with normal gammaGT, respectively, and individual bile acid composition was similar in the two groups. By univariate analysis, serum gammaGT level was linearly related to total serum bile acid (P < 0.05) and to cholestasis score (P < 0.001) among other variables, but steatosis score (P < 0.001) and Knodell score (P < 0.04) were the only variables independently associated with elevated serum gammaGT level by multivariate analysis.

CONCLUSIONS

Increased serum gammaGT level in patients with chronic hepatitis C is associated with liver steatosis and fibrosis, and indicates more advanced liver disease rather than reflecting the cholestasis that often accompanies this condition.

Gamma-glutamyltransferase activity and development of the metabolic syndrome (International Diabetes Federation Definition) in middle-aged men and women: Data from the Epidemiological Study on the Insulin Resistance Syndrome (DESIR) cohort

OBJECTIVE

Among hepatic enzymes, gamma-glutamyltransferase (GGT) is the main predictor of type 2 diabetes incidence, although it has not been shown that GGT predicts pre-diabetes states. Our aim was to study the association of GGT with the development of the metabolic syndrome (MetS).

RESEARCH DESIGN AND METHODS

We analyzed the 3-year data from the Data from Epidemiological Study on the Insulin Resistance Syndrome prospective cohort of 1,656 men and 1,889 women without MetS at baseline, according to the International Diabetes Federation definition.

RESULTS

Over 3 years, 309 participants developed the MetS. After adjustment for age, alcohol intake, physical activity, smoking habits, and alanine aminotransferase (ALT), the odds ratios for incident MetS increased across baseline GGT quartiles (1, 1.96, 2.25, and 3.81 in men, P < 0.03; and 1, 1.23, 1.80, and 1.58 in women, P < 0.05). After additional adjustment for insulin resistance markers (fasting insulin or homeostasis model assessment of insulin resistance index), the association was attenuated and the linear relation no longer significant in both sexes (P = 0.08, P = 0.16). However, men in the highest in comparison to the lowest quartile of GGT retained a significant risk for incident MetS. In women, there was no longer a significant risk. GGT was significantly associated with the 3-year incidence of individual components of the MetS. The incidence of the MetS also increased with ALT, but after adjustment on GGT this association remained significant only in women.

CONCLUSIONS

GGT, a predictor of type 2 diabetes, was associated with a risk of incident MetS. This association was mainly related with insulin resistance but was independent of other confounding factors.

The association of serum gamma glutamyltransferase with components of the metabolic syndrome in the Korean adults

The metabolic syndrome (MS) is a cluster of risk factors for cardiovascular disease related to insulin resistance. Recently, serum gamma glutamyltransferase (GGT) has been proposed as a marker of oxidative stress and is associated with a marked increase in the risk of cardiovascular disease. So, we investigated the association between serum GGT and components of the metabolic syndrome in the Korean adults. A total 3246 adults (aged 20-70 years, 1622 men and 1624 women) who visited Center for Health Promotion in Pusan National University Hospital for a medical checkup were included. We measured serum GGT and lipid profiles, fasting glucose, fasting insulin and blood pressure. As the quartile of serum GGT increased, the number of components of MS and prevalence of MS were increased. Serum GGT was also increased according as the number of components of MS was increased. A significant correlation (r=0.200, p<0.001 in men and r=0.133, p<0.001 in women) was noted between the numbers of the components of the MS and serum GGT. In addition, serum GGT was correlated significantly (r=0.266, p<0.001 in men and r=0.264, p<0.001 in women) with homeostasis model assessment of insulin resistance (HOMA-IR). In linear regression model, serum GGT was mainly influenced by the concentration of triglycerides and fasting glucose. In conclusion, serum GGT is closely related with insulin resistance and the increased number of components of MS. Among components of MS, serum GGT may be more associated with dyslipidemia and abnormal glucose tolerance, suggesting that serum GGT has more relationship with hepatic insulin resistance regardless of non-alcoholic fatty liver disease.

Gamma-glutamyltransferase, redox regulation and cancer drug resistance

Gamma-glutamyltransferase, a key enzyme of GSH metabolism, can modulate crucial redox-sensitive functions, such as antioxidant/antitoxic defences and cellular proliferative/apoptotic balance, with potential implications in tumour progression and drug resistance. Recent studies have elucidated the mechanisms of GGT involvement in various pathological processes suggesting its potential role as therapeutic target and diagnostic/prognostic marker.

A Strong Interaction between Serum γ-Glutamyltransferase and Obesity on the Risk of Prevalent Type 2 Diabetes: Results from the Third National Health and Nutrition Examination Survey

Background: Some studies have found an association of obesity with type 2 diabetes only among individuals with high normal serum γ-glutamyltransferase (GGT) activity, not in those with low serum GGT. If this interaction reflected pathophysiology, it would have scientific and clinical importance. The findings failed to reach statistical significance, however, and no articles have focused on the topic. We investigated possible interactions between serum GGT and body mass index (BMI) and their effects on the risk of prevalent type 2 diabetes and homeostasis model assessment (HOMA) insulin resistance.

Methods: We analyzed 4011 adults ≥40 years old who participated in the 3rd US National Health and Nutrition Examination Survey.

Results: BMI was associated with prevalent diabetes only among persons with high normal serum GGT activity (P for interaction = 0.002). In the highest serum GGT quartile, adjusted odds ratios for BMI 25–29.9, 30–34.5, and ≥35 kg/m2 compared with BMI&lt;25 kg/m2 were 3.1, 5.1, and 6.2, respectively (P for trend &lt;0.001). In the lowest serum GGT quartile, BMI was not associated with diabetes; corresponding adjusted odds ratios were 1.0, 0.9, 1.8, and 0.8 (P for trend = 0.551). After prevalent diabetes was excluded, there was a parallel interaction with HOMA levels (P for interaction &lt;0.001).

Conclusions: BMI was not associated with prevalent type 2 diabetes when GGT was low normal, suggesting that obesity itself may not be a sufficient risk factor for type 2 diabetes. Practically, this interaction can be useful in clinical settings to identify individuals at high risk for type 2 diabetes.

Persistent elevation of liver function enzymes within the reference range is associated with increased cardiovascular risk in young adults: the Bogalusa Heart Study

Elevations in alanine aminotransferase (ALT) and gamma-glutamyl transferase (GGT), markers of liver dysfunction and nonalcoholic fatty liver, are considered as part of the metabolic syndrome and related diseases. However, information is limited regarding the persistence (tracking) in levels of these enzymes over time and their influence on cardiovascular (CV) risk in young adults. The study sample consisted of white and black subjects (N = 489, 40% male, 73% white; baseline age, 18-32 years) followed over a period of 12 years as part of the Bogalusa Heart Study, with repeat measurements of CV risk factor variables and liver enzymes. Both at baseline and follow-up, males vs females had higher ALT (P < .01 to .0001) and GGT (P < .0001); blacks vs whites had higher GGT (P < .0001). With respect to persistence in enzyme levels over time, of those individuals who had ALT and GGT at the top quintile specific for age, race, and sex at baseline, about 50% of them continued to remain so with high values after 12 years. Individuals with levels persistently in the highest quintile vs those in the lowest quintile showed higher (P < .0001) body mass index, waist circumference, triglycerides, low-density lipoprotein cholesterol, glucose, insulin, insulin resistance index, and systolic and diastolic blood pressures; lower (P < .0001) high-density lipoprotein cholesterol; and higher (P < .05 to .001) prevalence of obesity, hypertension, dyslipidemia, metabolic syndrome as defined by the National Cholesterol Education Program Adult Treatment Panel III, positive parental history of type 2 diabetes, and coronary heart disease. In addition, based on a multivariate analysis using 2 separate models for ALT and GGT, baseline levels of both enzymes were independent predictors of follow-up; insulin resistance index and baseline GGT were also predictive of follow-up systolic blood pressure. Elevations in liver enzymes ALT and GGT, within "reference" range, persist over time and relate to clinically relevant adverse CV risk profile in young adults.

Gamma-Glutamyltransferase Activity and Total Antioxidant Status in Serum and Platelets of Patients with Community-acquired Pneumonia

BACKGROUND

We undertook this study to analyze serum and platelet gamma-glutamyltransferase (GGT) activity and total antioxidant status (TAS) concentration during the course of pneumonia and to compare them between patients with normal platelet count and those who developed reactive thrombocytosis.

METHODS

Platelet count, GGT activity and TAS concentration in serum (S) and platelet (Plt) isolates were measured in 60 patients with community-acquired pneumonia (CAP) on admission and at discharge.

RESULTS

At the end of treatment, platelet count increased significantly from the value recorded on admission. By the end of treatment, 42% of patients developed reactive thrombocytosis. Serum and platelet GGT activity was higher, whereas (S)TAS was significantly lower in CAP patients than in control subjects. On admission, (Plt)TAS was significantly higher in CAP patients as compared with control subjects; at discharge, (Plt)TAS was lower in comparison with either patient admission and control subjects. GGT activity and TAS concentration in serum and platelet isolate on admission did not differ significantly between patients with and without thrombocytosis. At discharge, (S)GGT activity showed no significant changes, whereas (Plt)GGT decreased significantly in patients with thrombocytosis as compared with those without thrombocytosis. In patients with thrombocytosis, (S)TAS concentration showed no significant difference, whereas (Plt)TAS concentration measured at discharge was significantly lower in patients with thrombocytosis as compared to those with normal platelet count.

CONCLUSIONS

The pattern of changes in (Plt)GGT catalytic activity and TAS concentration might be indicative of a certain role of thrombocytosis during treatment in patients with CAP. Further investigations are necessary to clarify these changes.

The relationship between gamma-glutamyltransferase and adiponectin in nonalcoholic women

The relationship between adiponectin and gamma-glutamyltransferase (GGT) has yet to be clearly demonstrated especially in women. Among the parameters of the liver function test (LFT), it has become increasingly evident that GGT is associated with metabolic disease. The objective of this study was to characterize the relationship between adiponectin and GGT in nonalcoholic women without liver disease. The subjects in this study were recruited from participants in routine health examinations during February of 2004. Among the total of 115 subjects considered for recruitment, we ultimately included 86 patients without liver disease in the study after performing LFT and abdominal sonography. After a 12-hour overnight fast, levels of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, GGT, total cholesterol, high-density lipoprotein cholesterol, triglycerides, fasting plasma glucose, fasting insulin, and adiponectin were measured in all subjects. We found a significant negative correlation between adiponectin and GGT (r=-0.35, P<.001) and a significant positive correlation between GGT and homeostasis model assessment (HOMA) (r=0.29, P<.01) after controlling for the confounding influences of age and fat mass. Although GGT is clearly related to adiponectin and HOMA, we determined aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase were not significantly associated with adiponectin and HOMA. The present study suggests that only GGT among the LFTs is related to adiponectin in nonalcoholic women without liver disease.

Design, synthesis, and evaluation of gamma-phosphono diester analogues of glutamate as highly potent inhibitors and active site probes of gamma-glutamyl transpeptidase

Gamma-glutamyl transpeptidase (GGT, EC 2.3.2.2) catalyzes the transfer of the gamma-glutamyl group of glutathione and related gamma-glutamyl amides to water (hydrolysis) or to amino acids and peptides (transpeptidation) and plays a central role in glutathione metabolism. GGT is involved in a number of biological events, such as drug resistance and metastasis of cancer cells by detoxification of xenobiotics and reactive oxygen species through glutathione metabolism, and is also implicated in physiological disorders, such as Parkinson's disease, neurodegerative disease, diabetes, and cardiovascular diseases. In this study, we designed, synthesized, and evaluated a series of gamma-phosphono diester analogues of glutamate as transition-state mimic inhibitors of GGT. The electrophilic phosphonate diesters served as highly potent mechanism-based inhibitors that caused the time-dependent and irreversible inhibition of both the E. coli and human enzymes, probably by phosphonylating the catalytic Thr residue of the enzyme. In particular, one of the inhibitors exhibited more than 6000 times higher activity toward human GGT than acivicin, a classical but nonselective inhibitor of GGT. The dependence of the inactivation rate on the leaving group ability of the phosphonates (Brønsted plot) revealed that the phosphonylation of the catalytic Thr residue proceeded via a dissociative transition-state with substantial bond cleavage between the phosphorus and the leaving group for both E. coli and human GGTs. The binding site of GGT for the Cys-Gly moiety of glutathione or for the acceptor molecules was probed by the phosphonate diesters to reveal a significant difference in the mechanism of substrate recognition between E. coli and human GGT. Thus, in the human enzyme, a specific residue in the Cys-Gly binding site played a critical role in recognizing the Cys-Gly moiety or the acceptor molecules by interacting with the C-terminal carboxy group, whereas the Cys side chain and the Cys-Gly amide bond were not recognized significantly. In contrast, the E. coli enzyme was a nonselective enzyme that accommodated substrates without specifically recognizing the C-terminal carboxy group of the Cys-Gly moiety of gamma-glutamyl compounds or the acceptor molecules. The phosphonate diester-based GGT inhibitors shown here should serve as a blue print for the future design of highly selective GGT inhibitors for use as drug leads and biological probes that gain insight into the hitherto undefined physiological roles of GGT and the relationships between GGT and a variety of diseases.

Gamma glutamyltransferase and long-term survival: is it just the liver?

BACKGROUND

Increased gamma glutamyltransferase (GGT) is associated with cardiovascular disease. To date, however, few studies with sufficient sample size and follow-up have investigated the association of GGT with all-cause mortality.

METHODS

The relation of GGT to the risk of death was examined in a cohort of 283 438 first attendants (inpatients or outpatients) of the Vienna General Hospital with request for GGT analysis as part of a routine screening panel and was monitored for up to 13 years. To evaluate GGT as a predictor, Cox proportional hazards models were calculated, which were adjusted for age and sex.

RESULTS

In both men and women, GGT above the reference category (GGT > or = 9 U/L in women, > or = 14 U/L in men) was significantly (P <0.001) associated with all-cause, cancer, hepatobiliary, and vascular mortalities. Hazard ratios (HRs) for men and women were similar in all categories. Among patients who presented with GGT above the reference category, those younger than 30 years had higher all-cause mortality rates than did older individuals (HR 1.5-3.3 vs HR 1-1.3 >80 years, respectively).

CONCLUSIONS

GGT is associated with mortality in both men and women, especially in patients younger than 30 years, and even high-normal GGT is a risk factor for all-cause mortality.

Type 2 diabetes and hearing loss in personnel of the Self-Defense Forces

The association of type 2 diabetes with hearing loss was evaluated in middle-aged male personnel of the Self-Defense Forces (SDFs). Hearing loss was defined as the pure-tone average (PTA) of the thresholds frequency at 0.5, 1, 2, and 4 kHz greater than 25 dB hearing levels (HL) in the worse ear. Diabetes status was determined by self-report of physician-diagnosed diabetes or by oral glucose tolerance test (OGTT). Of 699 subjects studied (age 52.9+/-1.0 years), 103 subjects were classified as having type 2 diabetes. Fasting plasma glucose of diabetic subjects was 120+/-19 mg/dl. Hearing loss levels were (worse) higher among diabetic subjects compared with subjects with normal glucose tolerance (NGT) (30.7+/-13.0 dB versus 27.4+/-12.3 dB, P=0.014). Hearing loss was more prevalent among diabetic subjects than among subjects with normal glucose tolerance (60.2% versus 45.2%, P=0.006). The odds ratio (OR) of type 2 diabetes for the presence of hearing loss was 1.87 (95% confidence interval 1.20-2.91, P=0.006) in a logistic regression analysis adjusted for age, rank, cigarette smoking and ethanol consumption. These results suggest that type 2 diabetes is associated with hearing loss independently of lifestyle factors in middle-aged men.

Alcoholic Beverage Preference, 29-Year Mortality, and Quality of Life in Men in Old Age

BACKGROUND

Harms of excessive alcohol consumption are obvious, but moderate wine consumption is frequently advocated for prevention of cardiovascular diseases. We compared 29-year mortality and quality of life in old age by alcoholic beverage preference (beer, wine, or spirits) in a cohort of men whose socioeconomic status was similar in their adult life.

METHODS

In 1974, cardiovascular risk factors and beverage preference were assessed in 2468 businessmen and executives aged 40-55 years. Of them, 131 did not use alcohol, 455 did not report a single preference, and 694, 251, and 937 preferred beer, wine, and spirits, respectively. Quality of life with a RAND-36 Short Form (SF)-36 instrument was surveyed in 2000 in survivors. Mortality was retrieved from registers during the 29-year follow-up.

RESULTS

Alcoholic beverage preference tracked well during the follow-up. Total alcohol consumption was not significantly different between preference groups. Men with wine preference had the lowest total mortality due to lower cardiovascular mortality. With the spirits group as the reference category and age, cardiovascular risk factors, and total alcohol consumption as covariates, wine drinkers had a 34% lower total mortality (relative risk 0.66; 95% confidence interval, 0.45-0.98); relative risk for beer preferers was 0.91 (95% confidence interval, 0.68-1.14). In 2000, wine preferers had the highest scores in all RAND-36 scales; general health (p =.007) and mental health (p =.01) were also significantly different.

CONCLUSION

In this male cohort from the highest social class, wine preference was associated with lower mortality and better quality of life in old age. Mortality advantage was independent of overall alcohol consumption and cardiovascular risk factors, but contributing personal characteristics or early life differences cannot be excluded.

Association Between Serum Gamma-Glutamyltransferase Level and Prehypertension Among US Adults

BACKGROUND

Higher serum gamma-glutamyltransferase (GGT) levels, a marker of oxidative stress, are implicated in the development and progression of hypertension; however, data from non-Caucasian ethnicities are limited. Also, currently there is little data available on the association between serum GGT level and clinically relevant blood pressure (BP) categories earlier in the disease continuum, when hypertension prevention efforts may be applicable. The association between serum GGT and prehypertension was examined in a nationally representative sample of US adults.

METHODS AND RESULTS

Cross-sectional study among 5,827 National Health and Nutrition Examination Survey 1999-2002 participants aged > or =18 years without cardiovascular disease (CVD) and hypertension. The main outcome-of-interest was the presence of prehypertension (systolic BP 120-139 mmHg or diastolic BP 80-89 mmHg) (n=2,269). Higher serum GGT levels were positively associated with prehypertension, independent of smoking, waist circumference, diabetes, cholesterol levels and other confounders. The multivariable odds ratio (95% confidence intervals) comparing quartile 4 of GGT (>29 U/L) to quartile 1 (<13 U/L) was 1.84 (1.37-2.46), p<0.0001. This association persisted in separate analyses among men and women. The results were consistent in subgroup analyses by race-ethnicity, age, smoking, alcohol intake, body mass index, waist circumference and diabetes. In non-parametric models, the positive association between serum GGT and prehypertension appeared to be present across the full range of GGT, without any threshold effect.

CONCLUSIONS

Higher serum GGT levels are associated with prehypertension in a nationally representative sample of US adults, free of CVD and hypertension.

Biochemical markers of alcoholism

Alcohol and alcohol-related diseases have become a major cause of death in Western countries. The most sensitive and specific of the commonly used biomarkers of alcohol intake are carbohydrate-deficient transferrin (CDT), and the combination of gamma-glutamyltransferase (GGT) and CDT. Other widely used laboratory markers are GGT, mean corpuscular volume of erythrocytes and the ratio of aspartate aminotransferase to alanine aminotransferase. Blood ethanol levels reveal recent alcohol use. However, more specific and sensitive biomarkers to improve the detection of excessive alcohol use at an early stage are needed. New biomarkers, not yet used in routine clinical work, include phosphatidylethanol, fatty acid ethyl esters, ethyl glucuronide, sialic acid, and acetaldehyde adducts.

Gamma glutamyl transferase and metabolic syndrome, cardiovascular disease, and mortality risk: the Framingham Heart Study

OBJECTIVE

To determine whether serum gamma-glutamyl transferase (GGT) predicts cardiovascular disease (CVD) morbidity and mortality, accounting for temporal changes in known CVD risk factors and C-reactive protein (CRP).

METHODS AND RESULTS

In 3451 Framingham Study participants (mean age 44 years, 52% women) we examined the relations of GGT with CVD risk factors, and prospectively determined the risk of new-onset metabolic syndrome, incident CVD, and death. GGT was positively associated with body mass index, blood pressure, LDL cholesterol, triglycerides, and blood glucose in cross-sectional analysis (P<0.005). On follow-up (mean 19 years), 968 participants developed metabolic syndrome, 535 developed incident CVD, and 362 died. The risk of metabolic syndrome increased with higher GGT (multivariable-adjusted hazard ratio [HR] per SD increment log-GGT, 1.26 [95%CI; 1.18 to 1.35]). Adjusting for established CVD risk factors (as time-dependent covariates updated quadriennially) and baseline CRP, a 1-SD increase in log-GGT conferred a 13% increase in CVD risk (P=0.007) and 26% increased risk of death (P<0.001). Individuals in the highest GGT quartile experienced a 67% increase in CVD incidence (multivariable-adjusted HR 1.67, 95%CI; 1.25 to 2.22).

CONCLUSIONS

An increase in serum GGT predicts onset of metabolic syndrome, incident CVD, and death suggesting that GGT is a marker of metabolic and cardiovascular risk.

Significance of low or normal serum gamma glutamyl transferase level in infants with idiopathic neonatal hepatitis

INTRODUCTION

We evaluated the significance of low/normal serum gamma glutamyl transferase (GGT) level in infants with idiopathic neonatal hepatitis (INH).

MATERIALS AND METHODS

A retrospective review of the hospital records of 103 infants less than 3 months of age who were diagnosed with INH between August 1991 and November 2000 was performed. Variables including age at which jaundice was noticed, age at presentation, perinatal risk factors, family history of liver disease, parental consanguinity, initial ultrasound scan, liver biopsy, laboratory values at the first visit, the peak levels of total bilirubin, aspartate aminotransferase (AST), GGT and alkaline phosphatase (ALP) in the first 3 months of follow-up and interval for normalisation of serum bilirubin and AST were compared between infants presenting with low/normal GGT (<or=100 U/L) and raised GGT (>100 U/L).

RESULTS AND DISCUSSION

Infants with low/normal GGT levels presented earlier (median 36.5 days versus 44 days; p=0.016) and had significantly higher bilirubin and AST levels at presentation (bilirubin 167.5 micromol/L versus 133 micromol/L; p<0.005 and AST 187.5 U/L versus 106 U/L; p<0.001) and at peak levels (bilirubin 170 micromol/L versus 146 micromol/L; p=0.024 and AST 210.5 U/L versus 129 U/L; p=0.001). A significant correlation was also found between GGT levels and serum albumin levels (p=0.004). Patients with low/normal GGT levels were more likely to have giant cell hepatitis on histology (p=0.015). There was no difference in time taken to recovery.

CONCLUSION

Low/normal levels of GGT in INH infants may be a predictor of more severe but recoverable disease.

Vital capacity and selected metabolic diseases in middle-aged Japanese men

OBJECTIVE

To elucidate the association between vital capacity and the presence of selected metabolic diseases in middle-aged Japanese men.

METHODS

A cross-sectional analysis of the associations among forced vital capacity (FVC), static vital capacity as a percentage of that predicted (%VC) and the presence of metabolic diseases was performed.

RESULTS

In a univariate linear regression analysis, FVC and %VC were inversely associated with poor vegetable intake, cigarette smoking and body mass index, but not with physical activity or ethanol consumption. In a logistic regression analysis adjusted for lifestyle factors, body mass index and age, the odds ratios for the presence of metabolic disease per 0.54 L (1 SD) decrease in FVC were 1.24 (95% CI 1.03 to 1.50) for type II diabetes, 1.21 (95% CI 1.02 to 1.42) for hypertension, 1.34 (95% CI 1.11 to 1.63) for hypertriglyceridemia, 1.23 (95% CI 1.03 to 1.46) for high gamma-glutamyl transferase levels and 1.63 (95% CI 1.10 to 2.41) for an episode of cardiovascular disease. FVC did not correlate with hyperhomocysteinemia, hypercholesterolemia or high white blood cell count. Similar results were also obtained for the association between %VC and metabolic diseases.

CONCLUSIONS

A decrease in FVC or %VC was associated with the presence of some metabolic diseases. The association may partly explain the reported association between low FVC and cardiovascular disease.

A microarray analysis of the murine macrophage response to infection with Francisella tularensis LVS

The response of cells of the mouse macrophage cell line J774 to infection with Francisella tularensis LVS was analysed by means of a DNA microarray representing approximately 18,500 genes (20,600 clones). The adaptive response was modest at all time points, and at most, 81 clones were differentially regulated from the time point of uptake of bacteria (0 min) up to 240 min later. For all five time points, 229 clones fulfilled the criteria of being differentially regulated, i.e. the ratio between infected versus non-infected cells was at least 1.7-fold up- or down-regulated and P <0.05. It was found that many of the differentially regulated genes are known to respond to stress in general and to oxidative stress specifically. However, at 120 min it was observed that genes that lead to depletion of glutathione were upregulated. Possibly, this was a result of mechanisms induced by F. tularensis. Generally, there was a conspicuous lack of inflammatory responses and, for example, although tumour necrosis factor alpha (TNF-alpha) was upregulated at 0 min, a significant down-regulation was noted at all subsequent time points. When cells were treated with an inhibitor of inducible nitric oxide synthase (iNOS) or the antioxidant N-acetylcysteine (NAC), the infection-induced cytopathogenic effect was significantly inhibited. Together, the results suggest that F. tularensis LVS infection confers an oxidative stress upon the target cells and that many of the host-defence mechanisms appear to be intended to counteract this stress. The infection is characterized by a very modest inflammatory response.

Coffee and health: a review of recent human research

Coffee is a complex mixture of chemicals that provides significant amounts of chlorogenic acid and caffeine. Unfiltered coffee is a significant source of cafestol and kahweol, which are diterpenes that have been implicated in the cholesterol-raising effects of coffee. The results of epidemiological research suggest that coffee consumption may help prevent several chronic diseases, including type 2 diabetes mellitus, Parkinson's disease and liver disease (cirrhosis and hepatocellular carcinoma). Most prospective cohort studies have not found coffee consumption to be associated with significantly increased cardiovascular disease risk. However, coffee consumption is associated with increases in several cardiovascular disease risk factors, including blood pressure and plasma homocysteine. At present, there is little evidence that coffee consumption increases the risk of cancer. For adults consuming moderate amounts of coffee (3-4 cups/d providing 300-400 mg/d of caffeine), there is little evidence of health risks and some evidence of health benefits. However, some groups, including people with hypertension, children, adolescents, and the elderly, may be more vulnerable to the adverse effects of caffeine. In addition, currently available evidence suggests that it may be prudent for pregnant women to limit coffee consumption to 3 cups/d providing no more than 300 mg/d of caffeine to exclude any increased probability of spontaneous abortion or impaired fetal growth.

gamma-Glutamyltransferase is a promising biomarker for cardiovascular risk

Oxidative stress plays a crucial role in a variety of clinical settings of atherogenesis, and mediates many pathways linked to atherosclerosis and inflammation. gamma-Glutamyltransferase (GGT), an enzyme responsible for the extracellular catabolism of antioxidant glutathione, may directly take part in atherogenesis and evolve as a potential biochemical risk indicator of cardiovascular morbidity and mortality. Classically, GGT has been thought of as a diagnostic tool for hepatobiliary disorders and alcohol abuse. More recently, growing body of data points out that serum GGT levels can aid detection of individuals at high risk for subsequent cardiovascular events, and thus have an application in primary and secondary prevention of cardiovascular disease. Although several investigations have shown that some drugs are effective in decreasing both serum lipids and GGT, and concomitantly the incidence of subsequent cardiovascular events; large-scale randomized trials are required to explore this impact directly. Based on current experimental and epidemiological studies, we postulate here that GGT present in the serum, even within its laboratory reference intervals regarded as physiologically normal, is a promising biomarker for cardiovascular risk.

Enzyme Catalytic Activities in Chronic Obstructive Pulmonary Disease

BACKGROUND

Altered muscle amino acid metabolism resulting in skeletal muscle dysfunction is one of the systemic effects of chronic obstructive pulmonary disease (COPD) associated with systemic oxidative stress and inflammation. The aim of the study was to investigate the existence and extent of changes in the activities of the enzymes catalyzing transamination reactions (aminotransferases), the enzyme involved in bone rearrangement (alkaline phosphatase), and the enzyme reflecting hypoxia that is characteristic of these patients (lactate dehydrogenase). In addition, the effect of cigarette smoking on these enzyme activities was also assessed.

METHODS

Enzyme activities such as alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, gamma-glutamyltransferase and lactate dehydrogenase were determined by standard analysis in sera of 29 COPD patients (FEV(1) = 46.6 +/- 12.1%) and 58 healthy subjects (21 nonsmokers, 17 ex-smokers and 20 smokers).

RESULTS

The activity of aspartate aminotransferase and alanine aminotransferase was significantly decreased, and the activity of lactate dehydrogenase increased in sera of COPD patients as compared with the group of healthy nonsmokers. According to centile values, the activity of alkaline phosphatase, gamma-glutamyltransferase and lactate dehydrogenase was increased in 50, 5, and 50% of COPD patients, respectively.

CONCLUSIONS

Study results revealed significant changes in the activities of transamination enzymes in patient sera, thus supporting the reports on altered amino acid metabolism in skeletal muscle in COPD. The elevated activity of alkaline phosphatase provides additional evidence for altered bone rearrangement in these patients. Smoking was not found to have any major effect on these enzyme activities in the present study.

An Inverse Association between Serum Gamma Glutamyl Transpeptidase Activity and Breslow's Lifestyle Index; Its Practical Application for Screening of Subjects with Unhealthy Lifestyles

We examined whether serum gammaGTP activity (gammaGTP) is associated with Breslow's lifestyle index and whether it could be used as a tool to detect subjects with unhealthy lifestyles. To that effect, 724 male Japanese workers excluding patients suffering from hepatitis virus infection, autoimmune liver diseases and apparently active bile duct diseases were cross-sectionally examined. gammaGTP was inversely associated with the total score of Breslow's index for all subjects (lambda=30.643) and in subjects aged 40 or more (lambda=37.073). The association was consistent even after adjustments of subjects' ages and levels of triglycerides, total cholesterol and uric acid (p=0.0001). Among the seven lifestyle factors comprising Breslow's index, improper habits of drinking (p<0.0001), smoking (p=0.0204), exercise (p=0.0189) and body weight control (p<0.0001), were associated with increased gammaGTP. Even in a survey in which subjects who had proper habits of drinking and body weight control were selectively examined, improper habits of smoking and exercise still tended to be associated with increased gammaGTP. Receiver operating characteristic curves indicated that gammaGTP was beneficial for detecting subjects who scored two or less on Breslow's index, at least in subjects aged 40 or more. gammaGTP was associated with insulin resistance level estimated by the homeostasis model assessment (p<0.0001), which was inversely associated with Breslow's index (p=0.0040). gammaGTP could be used as an objective substitute of Breslow's index, allowing us to identify subjects with low scores on Breslow's index, at least after sorting subjects properly. Such screening would enable interventions to correct subjects' unhealthy lifestyles, helping to solve lifestyle-related disease issues.

ADH1C*2 allele is associated with alcohol dependence and elevated liver enzymes in Trinidad and Tobago

Variants in alcohol dehydrogenase (ADH) genes differ between ethnic groups and have, in some studies, been found to be associated with alcohol dependence and alcoholic liver disease. This study sought to determine whether an association exists between ADH (ADH1C previously ADH3, ADH1B*2 previously ADH2*2) genotypes, alcohol dependence, drinking history, and liver function tests in the two major ethnic groups of Trinidad and Tobago (TT). One hundred and forty-five alcohol-dependent individuals of both East Indian (Indo-TT) and African (Afro-TT) ancestry, and 108 controls matched by age, sex, and education participated in the study. Serum levels of alanine and aspartate aminotransferase (ALT, AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), and gamma-glutamyltransferase (GGT) as well as presence of HIV, hepatitis B surface antigen, and anti-hepatitis C virus antibody were determined. There was a significant difference in the distribution of ADH1C allele polymorphisms between the ethnic groups (P<.0001). Forty-three percent of the Indo-TT were found to have one ADH1C*2 allele and 5% were homozygous, whereas, only 23% of Afro-TT had one allele and one was homozygous. Only three individuals had an ADH1B*2 allele (one Indo-TT alcohol dependent, two Indo-TT controls). The ADH1C*2 allele was significantly associated with alcohol dependence overall and within Indo-TT ancestry, however, it was not associated with current or heaviest alcohol consumption levels. Individuals with at least one ADH1C*2 allele also had significantly elevated levels of ALP (P<.02) and GGT (P<.02) as compared to individuals homozygous for ADH1C*. Additionally, GGT levels were also found to be elevated (P<.02) within Indo-TT alcohol dependents with at least one ADH1C*2 allele but not within the Afro-TT alcohol dependents with that allele. A linear regression that included alcohol dependence and levels of alcohol consumption confirmed that levels of serum GGT were significantly associated with the ADH1C*2 genotype. These results suggest that ADH1C polymorphisms are associated with alcohol dependence and alcohol associated elevations of liver enzymes in a population with a low frequency of ADH1B2 alleles.

Colorimetric coupled enzyme assay for γ-glutamyltransferase activity using glutathione as substrate

A colorimetric coupled enzyme assay for the determination of gamma-glutamyltransferase (GGT) activity using glutathione as substrate is described. The cysteine released from glutathione upon sequential action of GGT and leucine aminopeptidase is spectrophotometrically detected through its reaction with ninhydrin at 100 degrees C in acidic conditions. The method was applied to the determination of the activity of both bovine kidney and human serum GGT. In the described assay conditions with final GGT concentrations ranging from 0.18 to 4 mU/ml, a linear relationship between produced cysteine and incubation times up to 90 min was observed. When a standard chromogenic assay for GGT using L-gamma-glutamyl-3-carboxy-4-nitroanilide as substrate and the proposed assay were applied on the same serum sample a linear relationship between the two method was observed. Since the use of GSH as substrate, the proposed method can be usefully adopted for enzymological studies on GGT-related enzymes, a class of enzymes which is still waiting to be characterized.

Additive effects of moderate drinking and obesity on serum gamma-glutamyl transferase activity

BACKGROUND

Gamma-glutamyl transferase (GGT) is a widely used index of liver induction and a marker of alcohol overconsumption. Obesity has also been suggested to elevate serum GGT activities.

OBJECTIVE

The aim was to examine the links between moderate ethanol consumption, obesity, and GGT activities.

DESIGN

GGT values were recorded from 2490 persons (1184 men and 1306 women) who reported either no alcohol use (abstainers) or 1-40 g ethanol consumption per day (moderate drinkers). The study population was additionally classified according to body mass index (BMI; in kg/m2) as follows: < 19 (underweight), > or = 19 and < 25 (normal weight), > or = 25 and < 30 (overweight), and 30 (obese).

RESULTS

Significant main effects of sex (P < 0.0001), drinking habits (P < 0.01), and BMI (P < 0.001) on serum GGT activities were observed. The values were higher in the men than in the women and higher in those with higher BMIs. The highest activities were found to occur in persons with moderate drinking combined with overweight or obesity. A significant positive correlation between GGT and BMI (P < 0.0001) was observed, which was stronger for the men (r = 0.24) than for the women (r = 0.15, P < 0.05 for the difference between correlations).

CONCLUSION

The data indicate that serum GGT activities may respond to moderate drinking and overweight in an additive manner; this should be considered in the clinical use of GGT measurements and when defining normal GGT values in health care.

Association between alcohol consumption and aeroallergen sensitization in Danish adults

BACKGROUND

It has been proposed that alcohol consumption may be one of the lifestyle factors associated with a westernized, urban, and affluent lifestyle contributing to the rise in atopic disease.

OBJECTIVE

The aim was to investigate the association between alcohol consumption and atopy (aeroallergen sensitization).

METHODS

In 1982, a population-based cross-sectional study of 3608 Danes (79% of the invited), aged 30, 40, 50, and 60 years, was carried out. Information on alcohol consumption was obtained by a questionnaire. Aeroallergen sensitization was defined as a positive test for the detection of specific IgE against a panel of 19 common inhalant allergens in stored serum samples. A total of 3317 subjects with complete information on all variables were included in the analyses.

RESULTS

We found a statistically significant association between alcohol consumption and aeroallergen sensitization (independent of the type of alcoholic drink consumed). This association appeared to relate only to those who consumed more than 8 drinks/week. After adjustment for confounders this association was only statistically significant for those who consumed 15-21 drinks/week (adjusted odds ratio 1.8, 95% confidence interval 1.2-2.8).

CONCLUSION

In this adult general population, self-reported alcohol consumption was positively associated with aeroallergen sensitization.

Gamma-(monophenyl)phosphono glutamate analogues as mechanism-based inhibitors of gamma-glutamyl transpeptidase

Gamma-glutamyl transpeptidase (GGT, EC 2.3.2.2) catalyzes the hydrolysis and transpeptidation of extracellular glutathione and plays a central role in glutathione homeostasis. We report here the synthesis and evaluation of a series of hydrolytically stable gamma-(monophenyl)phosphono glutamate analogues with varying electron-withdrawing para substituents on the leaving group phenols as mechanism-based and transition-state analogue inhibitors of Escherichia coli and human GGTs. The monophenyl phosphonates caused time-dependent and irreversible inhibition of both the E. coli and human enzymes probably by phosphonylating the catalytic Thr residue of the enzyme. The inactivation rate of E. coli GGT was highly dependent on the leaving group ability of phenols with electron-withdrawing groups substantially accelerating the rate (Brønsted betalg = -1.4), whereas the inactivation of human GGT was rather slow and almost independent on the nature of the leaving group. The inhibition potency and profiles of the phosphonate analogues were compared to those of acivicin, a classical inhibitor of GGT, suggesting that the phosphonate-based glutamate analogues served as a promising candidate for potent and selective GGT inhibitors.

Serum gamma-glutamyltransferase is a predictor of incident coronary events in apparently healthy men from the general population

OBJECTIVE

To investigate whether serum gamma-glutamyltransferase (GGT) is an independent predictor for incident coronary events in initially healthy men from the general population.

METHODS AND RESULTS

The study was based on 1878 men (aged 25-64 years) who participated in the first MONICA Augsburg survey 1984/1985, and who were free of coronary heart disease at baseline. Up to 2002 a total of 150 incident acute coronary events occurred. Baseline levels of GGT were higher in men who experienced an event than in event-free men (28.4+/-2.0 units/l versus 22.4+/-2.1 units/l, p 0.0002). GGT was highly correlated with other cardiovascular risk factors. In a Cox proportional hazards model after age adjustment hazard ratios (HR) for incident myocardial infarction across GGT quartiles (<13, 13 to <20, 20 to <35, and >/=35 units/l) were 1.0, 1.84, 2.02, and 3.08 (p for trend 0.0001). Further adjustment for hypertension, TC/HDL ratio, diabetes, smoking, physical activity, alcohol intake, education years and BMI attenuated the association; comparing the highest versus lowest quartile of GGT the HR for a first-ever coronary event was then 2.34 (95% CI, 1.23-4.44).

CONCLUSIONS

Serum GGT is a strong predictor of acute coronary events in apparently healthy men from the general population, independent of other risk factors for cardiovascular disease.

Hepatic markers and development of type 2 diabetes in middle aged men and women: a three-year follow-up study. The D.E.S.I.R. Study (Data from an Epidemiological Study on the Insulin Resistance syndrome)

AIM

It has been shown, mainly in men, that gamma-glutamyltransferase (gammaGT) and alanine-aminotransferase (ALT) predict the development of type 2 diabetes. This study investigates the association between hepatic markers and the 3-year risk of diabetes.

METHODS

Incident diabetes was studied in 2071 men and 2130 women without diabetes at baseline from the D.E.S.I.R. cohort.

RESULTS

Adjusting on age, only gammaGT was predictive of diabetes in both sexes, whereas ALT and aspartate-aminotransferase (AST) were only predictive in men, and bilirubin was not predictive. After adjustment on classical confounding factors and on ALT activity, the odds ratios (OR) for incident diabetes increased across baseline gammaGT quartiles: 1, 3.1, 2.6, 5.0 in men (P<0.0003) and 1, 0.9, 3.2, 3.5 in women (P<0.01). The relations with ALT and AST were not significant after adjusting on gammaGT. Additional adjustment on markers of insulin resistance, BMI or fasting plasma glucose attenuated the risk associated with gammaGT in both sexes, and it remained significantly predictive only in the men. Pooling men and women, those with gammaGT above the median had adjusted ORs of developing diabetes of 13.7 (1.8-99.8) if WHR > =0.85 and 1.7 (0.6-4.8) if WHR<0.85 (interaction P<0.007).

CONCLUSION

gammaGT was the main hepatic risk marker for type-2 diabetes in both sexes, especially in subjects with central adiposity.

Proliferative effect of the aqueous extract of Hyptis pectinata on liver regeneration after partial hepatectomy in rats

PURPOSE: This study was carried out to assess the effects of the aqueous extract of Hyptis pectinata leaves on liver regeneration and on serum enzymes (AST, ALT and gamma-GT) after 67% partial hepatectomy in rats. METHODS: AST, ALT and gamma-GT, were determined by conventional procedures using a spectrophotometer (Model E2250-CELM). Liver regeneration was evaluated by immunohistochemical staining for proliferating cell nuclear antigen (PCNA). RESULTS:Oral pretreatment during 4 days at 100 mg/kg increased liver regeneration index. At 200 mg/kg, AST level was statistically decreased in comparison to the group submited to distilled water administration. The other enzymes assessed disclosed no difference when all groups were compared. CONCLUSION: The present study shows that the aqueous extract of Hyptis pectinata leaves contains some biological active principles that stimulate liver regeneration at 100 mg/kg and cause slight hepatic protection at 200 mg/kg.

Biological aging and Cox hazard analysis of mortality trends in a Mennonite community from south-central Kansas

This study investigated mortality in 568 individuals from the Goessel Mennonite community in rural central Kansas. There were three main objectives to this research: 1) characterize mortality trends within a biologically well-defined Mennonite community; 2) determine what biochemical, morphological, and physiological risk factors could be related to all-cause mortality, stratified by age and sex; and 3) compare these results to previously described variables that were associated with both biological age and mortality in this population. Mortality data were obtained from three sources: Kansas Vital Records, the Social Security death index, and church records. In total, 221 (39%) individuals were found to have died in this population between January 1980-June 2002. Analogous to the larger US population, the three leading causes of death in this community were heart disease, cancer, and stroke, accounting for 60% of all deaths. Besides advancing age, the greatest biological risk factor in this population was decreased amounts of albumin in men (relative risk, 2.47), potentially indicating underreported cases of either chronic kidney disease or frailty syndrome for males. Cox proportional hazard models demonstrated that increased amounts of total cholesterol may provide a protective effect for elderly individuals. We conclude, based on the previously described heritability of both albumin (h(2) = 0.40) and total cholesterol (h(2) = 0.50) in this population, that underlying genetic factors associated with both chronic degenerative diseases and biological aging may have important implications for understanding mortality patterns in this community.

Serum gamma-glutamyltransferase and risk of type 2 diabetes mellitus in men and women from the general population

OBJECTIVES

To examine gender-specific associations between gamma-glutamyltransferase (GGT) and incident type 2 diabetes mellitus in a representative population-based sample in Germany.

DESIGN

Prospective population-based study.

METHODS

The study was based on 1851 men and 1836 women (aged 25-64 years) who participated in the first Monitoring Trends and Determinants on Cardiovascular Diseases (MONICA) Augsburg Survey 1984/1985, and who were free of diabetes at baseline. Incident cases of type 2 diabetes were assessed using follow-up questionnaires in 1987/1988, 1997/1998 and 2002/2003 and were validated with medical records. Gender-specific hazard ratios (HRs) were estimated from Cox proportional hazard models.

RESULTS

A total of 172 cases of incident type 2 diabetes amongst men and 109 amongst women were registered during a mean follow-up period of 14.7 years. In both sexes the risk of type 2 diabetes increased with increasing levels of serum GGT. After multivariable adjustment HRs for incident type 2 diabetes across GGT categories (<25th, <50th, <75th, <87.5th and > or =87.5th percentiles) were 1.0, 1.81, 2.37, 3.41 and 4.24 (P-value for trend <0.0001) in men and 1.0, 1.42, 1.48, 1.95 and 2.41 (P-value for trend 0.0179) in women. Obesity appeared to be more strongly associated with type 2 diabetes in women with GGT equal or greater than the median compared to women with GGT below the median. However, in men the association between obesity and type 2 diabetes was almost identical in the two groups.

CONCLUSIONS

The GGT is an important predictor for incident type 2 diabetes in men and women from the general population.

Role of diallyl tetrasulfide in ameliorating the cadmium induced biochemical changes in rats

Cadmium (Cd) is an ubiquitous environmental and occupational toxic metal concerned with a variety of adverse effects. The present study was undertaken to evaluate the role of diallyl tetrasulfide (DTS), an organosulfur compound in alleviating the Cd induced biochemical changes in male Wistar rats. During the experiment, rats were injected with Cd (3mg/(kgday)) subcutaneously alone or with oral administration of DTS at different doses (10, 20 and 40mg/(kgday)) for 3 weeks. In Cd treated rats, the activities of aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and gamma glutamyl transferase (GGT) were significantly increased in serum with elevated levels of bilirubin, urea and creatinine. The hemoglobin level and creatinine clearance were also significantly decreased in Cd treated rats. In addition, the levels of plasma lipid peroxidation markers: thiobarbituric acid reactive substances and lipid hydroperoxides were significantly increased while the levels of plasma reduced glutathione (GSH), Vitamins C and E were significantly decreased in Cd administered rats. Administration of DTS along with Cd significantly decreased the serum, liver and kidney markers towards near normal level in a dose dependent manner. DTS at a dose of 40mg/(kgday) was highly effective when compared to other doses (10 and 20mg/(kgday)). DTS also significantly reduced the accumulation of Cd in blood and tissues as well as decreased the level of lipid peroxidation markers with elevation of antioxidants in plasma. All these changes were accompanied by histological observations in liver. The obtained results demonstrated the beneficial effect of DTS in reducing the harmful effects of Cd.

Body fat distribution, liver enzymes, and risk of hypertension: evidence from the Western New York Study

Gamma-glutamyltransferase (GGT) has been associated with hypertension (HTN); however, the nature of this association remains unclear. GGT is a marker of alcohol consumption, but it is also related to the infiltration of fat in the liver (fatty liver). The association between GGT and HTN was examined in a 6-year longitudinal investigation among 1455 men and women who returned for the follow-up visit. Baseline variables included serum GGT, blood pressure, and anthropometric measures. Incident HTN was defined as blood pressure > or =140/90 or on antihypertensive medication at the follow-up visit. To eliminate individuals with potential liver pathology, analyses focused only on individuals with GGT within its normal range (n=897). Participants were divided in quintiles (Q) based on their baseline GGT levels. Multiple logistic regression analyses [odds ratio (95% confidence intervals)] revealed a significant association of GGT with incident hypertension [2.1 (1.1 to 4.0) Q5 versus Q1]. In subgroup analyses, GGT and HTN were significantly associated among both noncurrent and current drinkers, but only for participants above the median of anthropometric measures [eg, body mass index >26.4, 2.3 (0.9 to 5.7), waist circumference >86.1 cm, 3.7 (1.4 to 9.9), and abdominal height >19.8 cm, 3.1 (1.2 to 8.5), for Q5 versus Q1, in fully adjusted models]. These findings suggest that the association between GGT and hypertension is not caused solely by alcohol consumption and indicate that serum GGT, within its normal range, may predict hypertension among individuals with increased central fat distribution, suggesting that fatty liver may represent an important underlying mechanism for this association.

Heavy alcohol intake, homocysteine and Type 2 diabetes

Although moderate alcohol intake is associated with reduced risk of atherosclerotic disease in both the general population and in diabetic patients, a recent report suggests that heavy alcohol intake facilitates the development of atherosclerosis exclusively in diabetic individuals. We studied cross-sectionally the effects of the interaction between ethanol consumption category and the prevalence of diabetes on plasma total homocysteine (tHcy), a risk factor for atherosclerotic disease, in middle-aged men. Heavy drinking was associated with elevated tHcy levels only in diabetic subjects but not in non-diabetic subjects. Plasma tHcy of heavy drinkers (average ethanol consumption > 30 ml/day) was higher than that of abstainers in the diabetic subgroup (10.25 +/- 3.39 vs. 8.88 +/- 1.94 micromol/l, P < 0.05), whereas tHcy levels in heavy drinkers were comparable with that of abstainers in the non-diabetic subgroup (9.36 +/- 2.52 vs. 9.12 +/- 2.10 micromol/l, NS). In a two-factor anova, significant interaction was observed on the effects of ethanol consumption category and diabetes prevalence on tHcy levels (P < 0.01). Confounding factors including folate, vitamin B(12), creatinine, age or cigarette smoking did not contribute to the interaction. These findings may partly explain the reported association between heavy drinking and atherosclerosis in diabetic subjects.

Gamma-glutamyltransferase as a risk factor for cardiovascular disease mortality: an epidemiological investigation in a cohort of 163,944 Austrian adults

BACKGROUND

There is evidence from recent studies that gamma-glutamyltransferase (GGT) is likely to be associated with cardiovascular disease (CVD). However, few studies to date with sufficient sample size and follow-up investigated the association of GGT with CVD mortality.

METHODS AND RESULTS

The relation of GGT to the risk of death from CVD was examined in a cohort of 163,944 Austrian adults that was monitored for up to 17 years. To evaluate GGT as an independent predictor, Cox proportional hazards models were calculated, which adjusted for established risk factors. In both men and women, high GGT was significantly (P<0.001) associated with total mortality from CVD, showing a clear dose-response relationship. Adjusted hazard ratios (95% CI) per log GGT increase were 1.66 (1.40 to 1.98) in men and 1.64 (1.36 to 1.97) in women. In men, subgroup analyses showed that high GGT was positively associated with incident fatal events of chronic forms of coronary heart disease (P=0.009), congestive heart failure (P<0.001), and hemorrhagic (P=0.01) and ischemic stroke (P<0.001). No significant associations were observed for acute myocardial infarction (P=0.16). In women, hazard ratios suggested associations in all subgroups; however, for hemorrhagic and ischemic stroke they were not statistically significant (P=0.09 and P=0.07, respectively). In addition, subgroup analyses stratified by age revealed a stronger relationship of GGT in younger participants. Hazard ratios for total CVD were 2.03 (1.53 to 2.69) in men and 2.60 (1.53 to 4.42) in women younger than 60 years.

CONCLUSIONS

This study demonstrates in a large, prospectively observed cohort that GGT is independently associated with cardiovascular mortality.

Post-radiotherapy plasma total glutathione is associated to outcome in patients with head and neck squamous cell carcinoma

We have studied the role of systemic oxidative stress for survival of patients with head and neck squamous cell carcinomas (HNSCC). Patients with lowest plasma total GSH levels had the lowest 36 months survival. In patients with post-radiotherapy concentrations of plasma total GSH less than median value, about 73% died during the 36 months follow-up compared to about 21% of patients with GSH values above median. Systemic oxidative stress as assessed by low GSH in post-radiotherapy plasma is associated to outcome in HNSCC patients.

Efficacy of theanine is connected with theanine metabolism by any enzyme, not only drug metabolizing enzymes

Theanine increases the antitumor effect of doxorubicin (DOX) with decreasing adverse reaction. We clarified the mechanism by which theanine decreases the adverse reaction of DOX on any metabolizing enzymes of theanine. There was no change in the activity of any CYPs and the cytochrome P450 content by theanine treatment. Namely, it was considered that the decrease of DOX adverse reactions by theanine was not connected with CYP activity. In other words, it is shown that theanine has no effect on the metabolism of other medicines and is safe as a food (tea) or supplement. Glutathione S-transferase activity did not change in the theanine-alone group whereas increased in the theanine and DOX-combined group. These results suggested that theanine combination increased the conjugate with DOX and GSH, promoted the efflux of GS-DOX conjugates from the liver, and decreased DOX concentration in the liver. In medium containing theanine with glutaminase in vitro, glutamate gradually generated, showing that glutaminase reacted with theanine. Furthermore, the generation of glutamate increased by reaction of theanine and gamma-glutamyltranspeptidase (gamma-GTP), showed that gamma-GTP converted theanine to glutamate. It is expected that theanine metabolism occurred by hydrolysis and rearrangement reaction by gamma-GTP in the liver. Namely, it is suggested that the metabolism of theanine mediated by glutaminase and gamma-GTP and the increase of glutamate mediated GSH is important for theanine-induced action. In conclusion, it appeared that theanine does not change the biodistribution of combined drugs but it modulates biodistribution or damage to the relative site of GSH, and shows preventive effects in tissue.

Association of Working Conditions and Lifestyle with Increased Serum Gamma-Glutamyltransferase: A Follow-up Study

BACKGROUND

This study investigated the association of working conditions and lifestyle with the development of increased serum gamma-glutamyltransferase (GGT) in Japanese workers.

METHODS

A follow-up study was carried out on workers of a telecommunication enterprise who received their first annual health check-up between 1992 and 1996, when they were between 40 and 54 years of age. Workers who had high serum GGT (> or =60 IU/L in males, > or =30 IU/L in females), a past history of disease, or current illness at their first check-up were excluded from the analysis. In total, the study included 15,586 workers. The association between working conditions and lifestyle and development of increased serum GGT (> or =60 IU/L in males, > or =30 IU/L in females) was investigated by pooled logistic regression analyses.

RESULTS

In males, body mass index, consumption of alcohol (<2 times/week, 2-5 times/week, >5 times/week), smoking (<20 cigarettes/day, > or =20 cigarettes/day), rarely taking three meals a day, marked preference for salty meals, and little preference for vegetables were positively associated with the development of increased serum GGT. Preferences for fatty meals (marked, moderate) were negatively associated with the development of increased serum GGT. In females, age and BMI were positively associated with the development of increased serum GGT.

CONCLUSIONS

Applying a new statistical analysis to this retrospective cohort study of 5 years, we revealed the health influences of alcohol consumption, smoking and eating habits on increased serum GGT. On the other hand, this study indicated that shift work or other working conditions are not significant risk factors for increased serum GGT.

Oxidative status in patients with alcohol dependence: a clinical study in Taiwan

The aim of this study is to examine the relationship between alcohol dependence and oxidative status. The biochemical parameters and antioxidants status were measured among 28 patients with alcohol dependence. Nineteen healthy persons without drinking problem were recruited as the control subjects. The activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma glutamyltransferase (gamma-GT), and levels of cholesterol, triglyceride (TG), and uric acid were significantly increased in the specimen of patients compared with control. Serum malondialdehyde (MDA) levels of the patients were found to be significantly increased compared with controls and decreased after abstinence. Superoxide dismutase (SOD) and glutathione peroxidase (GPX) activities were, respectively, 86% and 37% lower in alcoholic patients. After 14 d of abstinence, SOD activity was significantly reduced by 85%, CAT by 52%, and GPX by 54%, whereas no change was found in activity of glutathione reductase (GR). The duration of alcohol dependence is significantly correlated with the levels of MDA. In addition, the activity of CAT was significantly correlated with MDA levels. The results of this study suggest that oxidative stress occurred during alcohol dependence and subsequently affected the antioxidants mechanisms.

Gamma-glutamyl transferase and airflow obstruction in middle-aged men

BACKGROUND

A relationship between pulmonary dysfunction and cardiovascular mortality has been described. The mechanism responsible for the relationship remains largely unknown.

METHODS

The association between airflow obstruction and selected cardiovascular risk factors including gamma-glutamyl transferase (gamma-GT) and total homocysteine was analyzed cross-sectionally in 954 middle-aged men. Airflow obstruction was assessed with %FEV(1) (FEV(1)/FVC).

RESULTS

Serum gamma-GT and white blood cell (WBC) count were higher in subjects with airflow obstruction (%FEV(1)<70%) than in those without it (76.9+/-164.3 IU/L vs. 55.9+/-67.9 IU/L, P=0.030; 6290+/-1590/microL vs. 5590+/-1410/microL, P<0.001). Airflow obstruction was not associated with body mass index, total cholesterol, triglycerides, fasting glucose, or systolic blood pressure, but there was a marginal association with total homocysteine. In a logistic regression analysis adjusted for smoking status and alcohol consumption, the odds ratios (95% confidence interval) of Delta100 IU/L increase in gamma-GT and Delta1000/microL increase in WBC count for the presence of airflow obstruction were 1.20 (0.97-1.48, P=0.090) and 1.21 (1.02-1.44, P=0.036), respectively.

CONCLUSIONS

Airflow obstruction was associated with gamma-GT. The association was independent of alcohol consumption category, but was attenuated by the addition of cigarette smoking status.

Cholestasis in acute stroke: an investigation on its prevalence and etiology

OBJECTIVE

Liver cholestatic enzymes and/or bilirubin occasionally occur in acute stroke and are usually, but not always, ascribed to comorbid conditions. We investigated the frequency and possible etiology of this phenomenon.

MATERIAL AND METHODS

Prospective evaluation of post-admission biochemical cholestasis of all patients hospitalized with acute stroke was conducted during a 21-month period.

RESULTS

Of 169 consecutive patients, 18 (10.7%) developed cholestasis. In 7 of the patients (4.1%; 4 M, 3 F, median age 70 years, range 57-82 years) no apparent cause of cholestasis could be found, and they were further evaluated (Group A). These patients were compared with 21 randomly selected stroke patients without cholestasis, matched for age and gender, and who acted as controls (Group B). Group A patients were in a deeper coma than the controls (Glasgow Coma Scale 3.4 +/- 0.8 versus 1.9 +/- 0.7, p < 0.001), associated with severe autonomic and hypothalamic involvement, while no such manifestations were present in Group B (p < 0.001). Cholestasis started on the 3rd-6th day and lasted up to the 11th-25th day, with maximum median levels of gamma-GT and serum alkaline phosphatase (SAP) of up to 4.38 (range 2.33-8.25) and 1.49 (range 0.63-2.56) times the upper limit of normal, respectively. Serum alanine aminotransferase (ALAT), total and direct bilirubin increased in Group A but not in Group B. The common bile duct was significantly wider in Group A than in Group B (7.7 +/- 0.5 versus 4.7 +/- 0.6 mm, p < 0.001) and within Group A during and after cholestasis (7.7 +/- 0.5 versus 4.7 +/- 0.5 mm, p < 0.001).

CONCLUSIONS

Transient cholestasis may occur in 4.1% of patients following acute stroke. Cholestasis is associated with deeper coma, autonomic and hypothalamic involvement and common bile duct dilatation without obstruction, possibly related to inordinate hypertonia of the sphincter of Oddi.

Gamma-glutamyl transferase and metabolic risk factors for cardiovascular disease

OBJECTIVE

To elucidate the mechanism of the reported association between serum gamma-glutamyl transferase (GGT) activity and cardiovascular mortality.

METHODS

Cross-sectional analysis of the relationship between serum GGT activity and the risk factors for cardiovascular disease was performed.

PATIENTS AND MATERIALS

Middle-aged Japanese male personnel of the Self-Defense Forces who underwent retirement check-up.

RESULTS

Serum GGT activity was associated with total cholesterol, triglyceride, fasting plasma glucose, total homocysteine and systolic blood pressure. The association remained in the analysis adjusted for possible confounders including cigarette smoking, ethanol consumption and body mass index.

CONCLUSION

The observed association between serum GGT and cardiovascular risk factors may partly explain the reported relationship between serum GGT activity and cardiovascular disease. Serum GGT activity may be regarded as a marker of cardiovascular risk factors or oxidative stress rather than a mere indicator of excessive ethanol consumption or obesity.

The significance of serum gamma-glutamyltransferase in cardiovascular diseases

Since early after the introduction of serum gamma-glutamyltransferase (GGT) in clinical practice as a reliable and widely employed laboratory test, epidemiological and prospective studies have repeatedly shown that this activity possesses a prognostic value for morbidity and mortality. The association is independent of possibly concomitant conditions of liver disease, and notably, a significant independent correlation of serum GGT exists with the occurrence of cardiovascular diseases (myocardial infarction, stroke). Experimental work has documented that active GGT is present in atherosclerotic plaques of coronary as well as in cerebral arteries. These findings, and the recently recognized functions of GGT in the generation of reactive oxygen species, indicate that serum GGT represents a true marker of cardiovascular diseases and underlying atherosclerosis. Further insights into potential therapeutic interest will probably be derived from studies investigating the origin of GGT activity in plaque tissue.

Adiponectin levels and cardiovascular risk factors in Japanese men with type 2 diabetes

Several cardiovascular risk factors correlate with adiponectin levels. It is not known whether total homocysteine, folate and gamma-glutamyl transferase levels correlate with adiponectin. We cross-sectionally analyzed the association between adiponectin and these cardiovascular risk factors in diabetic patients. One hundred and two male inpatients with type 2 diabetes without overt nephropathy or insulin use were studied. In a regression analysis of the quartiles of adiponectin, plasma levels of adiponectin were associated positively with HDL-cholesterol and age, and inversely with body mass index and HbA1c, but not with total homocysteine, folate or gamma-glutamyl transferase. Non-traditional cardiovascular risk factors such as homocysteine and folate levels were not associated with adiponectin levels in male type 2 diabetic patients who are not subject to insulin therapy.