The relationship of gamma-glutamyltransferase to C-reactive protein and arterial stiffness

Association of Serum γ-Glutamyltransferase With C-Reactive Protein Levels in Patients With Coronary Heart Disease

Serum γ-glutamyltransferase (GGT) levels have been shown to be associated with C-reactive protein (CRP) levels. Nevertheless, studies on this relationship in coronary heart disease (CHD) populations are limited. This study retrospectively assessed 17 523 patients with CHD undergoing GGT and CRP testing. They were divided into 3 groups according to GGT tertiles. The critical points for high CRP levels was 10.0 mg/L, which corresponded to the 75th percentile. Logistic regression analysis was used to analyze the association between GGT and CRP levels in CHD patients. The baseline analysis showed significant differences in related parameters among patients with CHD. Compared with GGT tertile 1 (T1), the odds ratio (OR) of T3 for GGT in CHD patients was 2.15 (95% confidence interval [CI]: 1.96-2.36). The association between GGT and CRP was higher in males (OR: 2.23; 95% CI: 1.98-2.52) than in females (OR: 2.18; 95% CI: 1.89-2.51). This study showed an association between serum GGT and CRP levels in patients with CHD. GGT may be an inflammatory marker and an additional measure for assessing cardiovascular risk.

Decomposition of the total effect for two mediators: A natural mediated interaction effect framework

Mediation analysis has been used in many disciplines to explain the mechanism or process that underlies an observed relationship between an exposure variable and an outcome variable via the inclusion of mediators. Decompositions of the total effect (TE) of an exposure variable into effects characterizing mediation pathways and interactions have gained an increasing amount of interest in the last decade. In this work, we develop decompositions for scenarios where two mediators are causally sequential or non-sequential. Current developments in this area have primarily focused on either decompositions without interaction components or with interactions but assuming no causally sequential order between the mediators. We propose a new concept called natural mediated interaction (MI) effect that captures the two-way and three-way interactions for both scenarios and extends the two-way MIs in the literature. We develop a unified approach for decomposing the TE into the effects that are due to mediation only, interaction only, both mediation and interaction, neither mediation nor interaction within the counterfactual framework. Finally, we compare our proposed decomposition to an existing method in a non-sequential two-mediator scenario using simulated data, and illustrate the proposed decomposition for a sequential two-mediator scenario using a real data analysis.

Sexual dimorphism in glutathione metabolism and glutathione-dependent responses

Glutathione is the most abundant intracellular low molecular weight thiol in cells and tissues, and plays an essential role in numerous cellular processes, including antioxidant defenses, the regulation of protein function, protein localization and stability, DNA synthesis, gene expression, cell proliferation, and cell signaling. Sexual dimorphisms in glutathione biology, metabolism and glutathione-dependent signaling have been reported for a broad range of biological processes, spanning the human lifespan from early development to aging. Sex-depended differences with regard to glutathione and its biology have also been reported for a number of human pathologies and diseases such as neurodegeneration, cardiovascular diseases and metabolic disorders. Here we review the latest literature in this field and discuss the potential impact of these sexual dimorphisms in glutathione biology on human health and diseases.

Gamma-glutamyltransferase, possible novel biomarker in colon diverticulosis: a case-control study

The gamma-glutamyltransferase (GGT) is recognized in medical practice as a useful indicator for the detection of liver lesions, especially those induced by the excessive consumption of alcoholic or cholesterol-associated drinks. The present study, although it includes a very small number of cases diagnosed with colon diverticulosis-diverticulitis associated with polyposis at the same intestinal level, identifies the presence of increased circulating concentrations of this enzyme in the serum. Its serum levels are tracked “dynamically” throughout a year after the diagnosis and start of the therapy. The study calls into question the release of the enzyme from the edge of the enterocytes’ brush-like edge, leading to the pathogenic disturbance of regional redox homeostasis. The hypothesis gives the circulating values of GGT predictive value for cellular oxidative stress, as well as for indirectly expressing the glutathione level in cytosol.

Serum gamma-glutamyltransferase is inversely associated with dietary total and coffee-derived polyphenol intakes in apparently healthy Japanese men

PURPOSE

Serum γ-glutamyltransferase (GGT) has been proposed as a marker of oxidative stress. Here, we examined the association between serum GGT and the dietary intake of polyphenols, which have antioxidant properties.

METHODS

A cross-sectional survey including 7960 apparently healthy Japanese men (aged 22-86 years) who participated in health checkups was conducted in Shizuoka, Japan. We analyzed these subjects' clinical serum parameters and lifestyle factors, including dietary polyphenol intake, which was evaluated by a self-administered questionnaire and by matching the subjects' food consumption data with our original polyphenol content database.

RESULTS

The average intake of polyphenols was 1157 ± 471 mg/day, and green tea was the largest source of polyphenols at 40%, followed by coffee at 36%. Dividing the population according to quintiles of total polyphenol intake, the difference in polyphenol intake from coffee between the groups was much greater than the difference in polyphenol intake from green tea. The analysis of the association between polyphenol intake and biological parameters showed a significant negative association between polyphenol intake and the levels of systolic and diastolic blood pressure (SBP and DBP), GGT, and alanine aminotransferase (ALT) after adjusting for age, smoking habit, energy intake and alcohol intake. The GGT levels were inversely associated with the polyphenol intake from coffee, but not with that from green tea. Multivariable linear regression analyses demonstrated that the subjects' GGT levels were negatively and independently associated with their polyphenol intake.

CONCLUSIONS

The intake of total polyphenol including coffee as a major contributor is inversely associated with the serum GGT concentration in Japanese males.

Gamma-glutamyltransferase and risk of cardiovascular mortality: A dose-response meta-analysis of prospective cohort studies

BACKGROUND

Serum gamma-glutamyltransferase (GGT) elevation likely contributes to cardiovascular (CV) mortality, however it has remained unknown whether a dose-response relationship exists between serum GGT and CV mortality.

METHODS

We searched the PubMed, EMBASE, and Cochrane library databases for prospective cohort studies published up to October 2, 2016. Summary hazard ratios (HRs) with their corresponding 95% confidence intervals (CIs) were calculated using a fixed effects model.

FINDINGS

Nine prospective studies, including 527,589 participants and more than 7,011 cases, were included in this meta-analysis. For the moderate, high, and highest levels of GGT, the pooled HRs of CV mortality were 1.11 (95% CI = 1.04-1.19), 1.29 (95% CI = 1.21-1.38) and 1.59 (95% CI = 1.47-1.72), respectively (all p < 0.05 as compared to the lowest levels of GGT). Additionally, the HR per incremental increase of GGT by 10 U/L was 1.10 (95% CI = 1.08-1.11). Evidence of a positive relationship with nonlinear trend for GGT elevation with CV mortality in females was found (P = 0.04 for nonlinearity). However, a linear model was better fit to illustrate the GGT-CV mortality among males (P = 0.304 for nonlinearity).

CONCLUSIONS

These findings indicate that serum GGT activity within the reference interval is positively associated with increased risk of CV mortality in a dose-response manner.

Gamma-glutamyl transferase and cardiovascular disease

Gamma-glutamyl transferase (GGT) is an enzyme located on the external surface of cellular membranes. GGT contributes in maintaining the physiological concentrations of cytoplasmic glutathione and cellular defense against oxidative stress via cleavage of extracellular glutathione and increased availability of amino acids for its intracellular synthesis. Increased GGT activity is a marker of antioxidant inadequacy and increased oxidative stress. Ample evidence suggests that elevated GGT activity is associated with increased risk of cardiovascular disease (CVD) such as coronary heart disease (CHD), stroke, arterial hypertension, heart failure, cardiac arrhythmias and all-cause and CVD-related mortality. The evidence is weaker for an association between elevated GGT activity and acute ischemic events and myocardial infarction. The risk for CVD or CVD-related mortality mediated by GGT may be explained by the close correlation of GGT with conventional CVD risk factors and various comorbidities, particularly non-alcoholic fatty liver disease, alcohol consumption, oxidative stress, metabolic syndrome, insulin resistance and systemic inflammation. The finding of GGT activity in atherosclerotic plaques and correlation of intra-plaque GGT activity with histological indexes of plaque instability may suggest a participation of GGT in the pathophysiology of CVD, particularly atherosclerosis. However, whether GGT has a direct role in the pathophysiology of CVD or it is an epiphenomenon of coexisting CVD risk factors or comorbidities remains unknown and Hill's criteria of causality relationship between GGT and CVD are not fulfilled. The exploration whether GGT provides prognostic information on top of the information provided by known cardiovascular risk factors regarding the CVD or CVD-related outcome and exploration of molecular mechanisms of GGT involvement in the pathophysiology of CVD and eventual use of interventions to reduce circulating GGT activity remain a duty of future studies.

Serum gamma-glutamyltransferase is not associated with subclinical atherosclerosis in patients with type 2 diabetes

BACKGROUND

This study investigated the association between serum gamma-glutamyltransferase (GGT) level and subclinical atherosclerosis in patients with type 2 diabetes.

METHODS

This cross-sectional study involved 1024 patients with type 2 diabetes mellitus. Measurement of brachial-ankle pulse wave velocity (baPWV; as a marker of arterial stiffness) and an ultrasound assessment of carotid atherosclerosis were performed. Subclinical atherosclerosis was defined by the presence of a high baPWV (≥1720 cm/s), carotid atherosclerosis (intima-media thickness >0.8 mm or the presence of plaques), and carotid stenosis (≥50 % of luminal narrowing). The subjects were stratified into quartiles according to GGT level, and the relationship between GGT level and subclinical atherosclerosis was analysed.

RESULTS

Serum GGT levels were closely associated with obesity, atherogenic dyslipidemia, and metabolic syndrome. However, serum GGT levels did not show a linear association with baPWV, carotid intima-media thickness, or plaque grade. The prevalence of high baPWV, carotid atherosclerosis, and carotid stenosis did not differ between the quartiles in men and women. Multivariate logistic regression analyses revealed no association between GGT level and high baPWV, carotid atherosclerosis, and carotid stenosis, either as continuous variables or quartiles.

CONCLUSIONS

Serum GGT levels were significantly associated with obesity, atherogenic dyslipidaemia, and metabolic syndrome, but not with the early and late stages of atherosclerotic vascular changes, in patients with type 2 diabetes. Serum GGT level may not be a reliable marker of subclinical atherosclerosis in type 2 diabetes.

Adjuvant sorafenib therapy in patients with resected hepatocellular carcinoma: evaluation of predictive factors

Currently there is no predictor for survival after adjuvant sorafenib in patients with hepatocellular carcinoma (HCC) who have undergone curative resection. Thirty-eight patients who underwent curative resection of HCC received adjuvant sorafenib therapy between August 2009 and March 2012. Clinicopathological parameters including patient factors, tumor factors, liver background, and inflammatory factors (before surgery and dynamic changes after sorafenib therapy) were evaluated to identify predictors for overall survival (OS) and recurrence-free survival (RFS). The recurrence rate, mortality rate, and clinicopathological data were also compared. Increased NLR after sorafenib (HR = 3.199, 95 % CI 1.365-7.545, P = 0.008), increased GGT after sorafenib (HR = 3.204, 95 % CI 1.333-7.700, P = 0.009), and the presence of portal vein thrombosis (HR = 2.381, 95 % CI 1.064-5.328, P = 0.035) were risk factors related to RFS. By contrast, increased NLR after sorafenib was the only independent risk factor related to OS (HR = 4.647, 95 % CI 1.266-17.053, P = 0.021). Patients with increased NLR or increased GGT after sorafenib had a higher incidence of recurrence and death. Patients who had increased NLR tended to have higher preoperative levels of NLR and GGT. There were no differences in clinicopathological factors in patients with increased GGT and decreased GGT. In conclusion, increased NLR predicted a worse OS and RFS in patients with HCC who underwent curative resection with adjuvant sorafenib therapy. Increased GGT predicted a worse OS. NLR and GGT can be monitored dynamically before and after sorafenib therapy.

Alcohol intake, hypertension development and mortality in black South Africans

BACKGROUND

Excessive alcohol intake is a risk factor for cardiovascular disease (CVD) and predicts cardiovascular and all-cause mortality. We determined which alcohol marker (self-reported alcohol intake, gamma-glutamyltransferase (GGT) or percentage carbohydrate deficient transferrin (%CDT)) relates best with mortality and predicts hypertension development over five years in black South Africans.

DESIGN

This was a longitudinal study as part of the PURE (Prospective Urban and Rural Epidemiology) study in the North West Province, South Africa.

METHOD

We included 2010 participants and followed 1471 participants. Over five years, 230 deaths occurred, of which 66 were cardiovascular-related. At enrolment, participants completed questionnaires on alcohol intake (yes, for former and current use; no, for alcohol never used). We measured blood pressure, collected blood samples and measured GGT and %CDT.

RESULTS

When comparing hazard ratios (HRs) of self-report, GGT and %CDT, we found that only GGT predicted cardiovascular (HR = 2.76 (1.49-5.12)) and all-cause mortality (HR = 2.47 (1.75-3.47)) and hypertension development ((HR = 1.31 (1.06-1.62)). Participants self-reporting yes for alcohol intake had a 30% increased risk of developing hypertension (HR = 1.30 (1.07-1.60)) but not an increased risk for mortality. When adding both GGT and self-report in the prediction model for hypertension, only self-reporting of alcohol was significant (HR = 1.24 (1.01-1.53)). The alcohol marker, %CDT, did not show any significant association with mortality or hypertension development.

CONCLUSION

GGT independently predicted cardiovascular and all-cause mortality, as well as hypertension development in black South Africans. Despite non-specificity to excessive alcohol consumption, GGT may be a useful general marker for hypertension development and mortality, also due to its significant association with self-reported alcohol intake.

Association between long working hours and serum gamma-glutamyltransferase levels in female workers: data from the fifth Korean National Health and Nutrition Examination Survey (2010-2011)

Objectives

The present study investigated the association between long working hours and serum gamma-glutamyltransferase (GGT) levels, a factor influencing the incidence of cardiovascular disease.

Methods

Data from the fifth Korean National Health and Nutrition Examination Survey (2010–2011) were used to analyze 1,809 women. Subjects were divided into three groups based on the number of weekly working hours: ≤29, 30–51, and ≥52 hours per week. Complex samples logistic regression was performed after adjusting for general and occupational factors to determine the association between long working hours and high serum GGT levels.

Results

The prevalence of high serum GGT levels in groups with ≤29, 30–51, and ≥52 working hours per week was 22.0%, 16.9%, and 26.6%, respectively. Even after adjusting for general and occupational factors, those working 30–51 hours per week had the lowest prevalence of high serum GGT levels. Compared to those working 30–51 hours per week, the odds ratios (OR) of having high serum GGT levels in the groups with ≥52 and ≤29 working hours per week were 1.56 (95% confidence interval [CI], 1.10–2.23) and 1.53 (95% CI, 1.05–2.24), respectively.

Conclusions

Long working hours were significantly associated with high serum GGT levels in Korean women.

Association between serum γ-glutamyltranspeptidase and atherosclerosis: a population-based cross-sectional study

OBJECTIVE

The purpose of this study was to determine the relationship between serum γ-glutamyltranspeptidase (GGT) and brachial-ankle pulse wave velocity (baPWV) as an indicator for atherosclerosis in Japanese men and women after adjusting for fatty liver.

DESIGN

A cross-sectional study.

SETTING

A health check-up centre in Japan.

PARTICIPANTS

912 Japanese men and women aged 24-84 years recruited from people who received a medical health check-up programme with a standardised questionnaire and an automatic waveform analyser to measure baPWV.

MAIN OUTCOME MEASURES

We measured serum GGT concentrations and baPWV. Fatty liver was diagnosed by standardised criteria using abdominal ultrasonography. The postmenopausal state was defined as beginning 1 year after the cessation of menses.

RESULTS

In women, log2 GGT was positively associated with baPWV (β=0.11, 95% CI 0.02 to 0.19, p<0.05), independent of age, body mass index, systolic blood pressure, fasting plasma glucose, triglycerides, estimated glomerular filtration rate, fatty liver, menopausal state and parameters of lifestyles. However, in men, the positive association of log2 GGT with baPWV was not significant (β=-0.04, 95% CI -0.10 to 0.03, p=0.28) in multivariable linear regression analyses.

CONCLUSIONS

The serum GGT level was associated with baPWV, independently of covariates including fatty liver or menopausal state just in women, but not in men.

Gamma Glutamyl Transferase Activity is Associated With Both Paraoxonase Activity and Aortic Stiffness in Hypertensive Patients

BACKGROUND

We aimed to investigate relationship between gamma glutamyl transferase (GGT) activity with paraoxonase 1 (PON1) activity and aortic stiffness (AS) parameters such as pulse wave velocity (PWV) and augmentation index (AIx).

METHODS

Measurements were obtained from 324 patients with newly diagnosed essential hypertension (mean age: 55.0 ± 8.2 years). The patients were divided into two groups according to their median GGT values. PWV and AIx were calculated using the single-point method via the Mobil-O-Graph® ARCsolver algorithm.

RESULTS

PWV, Aix, and high-sensitive C-reactive protein (hs-CRP) values were higher and PON1 activity values were lower in GGThigh group compared with GGTlow group (P < 0.05, for all). Multiple linear regression analysis showed that GGT activity was independently associated with PWV (β = 0.496, P < 0.001) and PON1 activity (β = -0.343, P < 0.001) as well as hs-CRP (β = 0.334, P < 0.001).

CONCLUSION

These results may support that increased GGT activity would be associated with both impaired antioxidant system and increased AS in hypertensive patients.

Relationships of gamma-glutamyltransferase and beta 2-microglobulin on high sensitivity C-reactive protein among Japanese elementary school children

Recent studies reported that gamma-glutamyltransferase (GGT) and beta 2-microglobulin (β2M) are possible markers of cardiovascular disease in adults, however, their roles among children have not been fully elucidated. We have examined the relationships of GGT and β2M on C-reactive protein (CRP) among 326 healthy elementary school children. To investigate the relationships of serum GGT and β2M levels on measuring of CRP, multiple regression analysis and analysis of covariance (ANCOVA) were performed. After being adjusted for confounders, body mass index, log-transformed GGT, and β2M were significantly related to CRP. Independent of other risk factors, ANCOVA showed that serum β2M levels were significantly associated with serum CRP (p=0.012, p for trend <0.001), and GGT levels had similar results (p=0.211, p for trend=0.035). These results suggest that serum β2M and GGT levels are useful indicators for evaluating the occurrence of slight inflammation as background, which promotes atherosclerosis even in healthy children.

Serum γ-GTP activity is closely associated with serum CRP levels in non-overweight and overweight middle-aged Japanese men

The relationship between γ-glutamyltransferase (γ-GTP) and C-reactive protein (CRP) has not been established, particularly in the lean or non-overweight population. In the present study, we examined the associations between γ-GTP and CRP in non-overweight and overweight middle-aged Japanese men. We conducted a cross-sectional study of 4,271 apparently healthy men aged 40 to 64 y (mean±SD, 50.5±6.6 y) who participated in health checkups. Associations between serum CRP levels, other clinical parameters, and lifestyle factors were analyzed using Spearman's rank correlation coefficient analysis and multiple linear regression analysis in the non-overweight (body mass index [BMI]<25 kg/m(2)) and overweight (BMI≥25 kg/m(2)) men. Associations between serum γ-GTP activity and serum CRP levels were analyzed using analysis of covariance by comparisons of serum CRP levels of four subgroups according to γ-GTP status. In non-overweight men, BMI, high-density lipoprotein cholesterol, triacylglycerols, fasting blood glucose, aspartate aminotransferase, γ-GTP, and smoking habit were positively associated with serum CRP levels. In overweight men, BMI, diastolic blood pressure, triacylglycerols, and γ-GTP were positively associated with serum CRP levels. After adjustment for age, BMI, smoking status, and alcohol intake, dose-response relationships were observed between γ-GTP and CRP levels in both overweight and non-overweight men. The results of this study indicate that an increase in serum γ-GTP activity is closely associated with elevated CRP levels in both non-overweight and overweight middle-aged Japanese men.

Elevated Serum Gamma-Glutamyltransferase (GGT) Activity and the Development of Chronic Kidney Disease (CKD) in Cigarette Smokers

BACKGROUND

Elevated serum gamma-glutamyltransferase (GGT) is predictive of various cardiovascular (CV) risk factors including chronic kidney disease (CKD). Elevated serum GGT has been recognized in smokers who are likely to develop CKD, but no study has focused on serum GGT and CKD in smokers.

OBJECTIVES

The aim of this study was to clarify the associations between cigarette consumption, elevation of serum GGT and the development of proteinuria and CKD.

PATIENTS AND METHODS

A retrospective 6-year observational study was conducted on 2,603 male workers aged between 40 and 64 years. Incidences of proteinuria detected by dipstick and CKD defined by proteinuria and/or reduced estimated glomerular filtration rate (eGFR) measured in health check-ups were determined 6 years later for those who had been free of them at baseline.

RESULTS

Higher means of serum GGT in smokers than in nonsmokers at baseline, and a higher incidence of elevated serum GGT in smokers than in nonsmokers during the 6-year period were recognized only for alcohol consumers. Incidences of proteinuria and moderate or severe CKD which has a high risk of future renal failure or CV disease were higher in the subjects with greater cigarette consumption or a higher serum GGT level. Multiple logistic regression analyses adjusting for major CV risk factors showed a significant interactive effect between smoking and elevated serum GGT on the development of proteinuria and an additive effect of smoking and serum GGT on the development of high-risk CKD.

CONCLUSIONS

Elevation of serum GGT in smokers, to a large extent, depends on the associated alcohol consumption. Elevated GGT in smokers plays at least a partial role in the development of CKD, mainly proteinuria, and the underlying mechanisms remain to be elucidated.

Dose-response relationship between serum γ-glutamyltransferase and arterial stiffness in Korean adults: the Namwon Study

Background

The results of epidemiologic studies of the association between serum γ-glutamyltransferase (GGT) and brachial–ankle pulse wave velocity (baPWV) have been inconsistent. We examined the association between serum GGT and arterial stiffness in a general population of Korean adults.

Methods

The study population consisted of 6314 community-dwelling Koreans who participated in the baseline survey of the Namwon Study. We analyzed sex-specific association between serum GGT and arterial stiffness, as measured by baPWV.

Results

There was a significant progressive increase in age-adjusted mean baPWV across quartiles of GGT in both sexes. In fully adjusted analysis, as compared with the lowest quartile, the odds ratios (95% CI) for high baPWV (ie, sex-specific fifth quintile) were 1.51 (1.03–2.23), 1.82 (1.22–2.72), and 2.80 (1.79–4.40) among men (P-trend <0.001), and 1.11 (0.81–1.52), 1.29 (0.94–1.76), and 1.47 (1.04–2.08) among women (P-trend <0.001), for the second, third, and fourth quartiles of GGT, respectively.

Conclusions

This population-based study examined the dose-response relationship between GGT and arterial stiffness as measured by baPWV in both sexes. The association between GGT and arterial stiffness was stronger among men. Additional longitudinal studies are needed to examine the relationship between GGT and arterial stiffness and clarify the mechanism underlying the association.

Association of serum gamma-glutamyltransferase with arterial stiffness in established coronary artery disease

Serum gamma-glutamyltransferase (GGT) has been reported to predict vascular risk. We enrolled 978 patients (507 men and 471 women) with established coronary artery disease (CAD). The GGT, brachial-ankle pulse wave velocity ([baPWV] to assess arterial stiffness), and conventional risk factors were evaluated. The means of baPWV tend to increase in both genders according to GGT tertiles. Body mass index, GGT, logarithmical (systolic blood pressure [LnSBP]), uric acid (UA), total bilirubin, Ln (cholinesterase), and Ln (total cholesterol) were correlated with baPWV in men in a multivariate model. However, only GGT, LnSBP, UA, and Ln (high-density lipoprotein cholesterol) were correlated with baPWV in women. The GGT was a significant determinant for increased baPWV both in men (β = 0.017; P < .001) and in women (β = 0.015; P < .001). In conclusion, GGT was independently associated with increased arterial stiffness both in men and in women with established CAD.

Association between γ-glutamyltransferase, adiponectin and arterial stiffness

AIM

Serum γ-glutamyltransferase (GGT) is used as a marker of hepatic dysfunction. Recently, several studies reported that GGT is significantly associated with cardiovascular mortality and atherosclerosis. Adiponectin is known to play an important role in the development of atherosclerosis, but its physiologic role has yet to be fully determined. In this study, we investigated the relationships among serum GGT, adiponectin and arterial stiffness.

METHODS

Of 4236 subjects recruited from 17 different medical centers in Seoul, Korea, 2846 subjects were enrolled in our study. The parameters of metabolic syndrome (MetS) were assessed in these subjects, and their plasma adiponectin levels and pulse wave velocity (PWV) were measured along with anthropometric and biochemical profiles, including GGT.

RESULTS

The subjects were stratified into 3 groups according to GGT values. PWV values gradually increased and the adiponectin level decreased with GGT tertiles. Aortic PWV showed a significant correlation with age, SBP, FPG, but there was no correlation among aortic PWV, GGT and adiponectin. Peripheral PWV demonstrated a significant correlation with age, SBP, DBP, BMI, WC, FPG and GGT, but there was no correlation between peripheral PWV and adiponectin. In multiple logistic regression analysis after adjusting for risk factors, GGT was a significant contributor to increased peripheral PWV.

CONCLUSIONS

These findings indicate that serum GGT is independently associated with increased arterial stiffness, but there was no correlation between adiponectin and arterial stiffness in both males and females.

Serum gamma-glutamyltransferase is associated with arterial stiffness in healthy individuals

OBJECTIVE

Gamma-glutamyltransferase (GGT) has been reported to be useful in predicting cardiovascular disease. Arterial stiffness measured by brachial-ankle pulse wave velocity (baPWV) is not only a marker of vascular damage but a significant predictor of cardiovascular events. Gender difference has been reported in the association between GGT and baPWV. We assessed, therefore, the association between GGT and baPWV in a large population and determined whether there was gender difference.

DESIGN

This cross-sectional study was conducted at the Asan Medical Centre, Seoul, Republic of Korea.

SUBJECTS AND MEASUREMENTS

Serum GGT, baPWV and conventional risk factors were measured in 10 988 apparently healthy subjects (7248 men, 3740 women) who participated in a routine health screening examination.

RESULTS

In both men and women, we observed positive linearity between GGT quartiles and body mass index, waist circumference, systolic blood pressure, diastolic blood pressure, fasting plasma glucose, total cholesterol, LDL cholesterol, triglycerides, uric acid, high-sensitive C-reactive protein (hsCRP) and homeostatic model assessment of insulin resistance (HOMA-IR) score (P for trends < 0·001). The proportion of individuals with diabetes, hypertension increased as the GGT quartile increased (P for trends < 0·001). Age-adjusted mean baPWV increased gradually in both males and females according to GGT quartiles (P for trends < 0·001 in both genders). The odds for higher baPWV (i.e. >75th percentile in each sex) were significantly higher in the highest compared with the lowest GGT quartiles, after adjustment for confounding variables, in both men [odds ratio (OR) = 1·63, 95% CI = 1·21-2·20] and women (OR = 1·56, 95% CI = 1·08-2·27).

CONCLUSIONS

These results suggest that GGT is independently associated with the increased level of arterial stiffness both in men and in women and the association between them appears to be stronger in men compared to women.

Serum γ-glutamyltransferase and associated damage among a She Chinese population

OBJECTIVE

It has been suggested that serum γ-glutamyltransferase is independently associated with cardiovascular mortality and atherosclerosis. The present study is to investigate the relationship between serum γ-glutamyltransferase and potential associated damage in an adult She Chinese population.

METHOD

A multistage, stratified, cluster, random sampling method was used to select an ethnically representative group of individuals aged 20-80 years in the general population. Brachial-ankle pulse-wave velocity was used to assess arterial stiffness in the general population and the Toronto Clinical Neuropathy Scoring System was used to detect diabetic peripheral polyneuropathy among populations with diabetes.

RESULTS

A total of 5385 subjects were entered into the analysis. Serum γ-glutamyltransferase levels were classified into four groups using the 25th, 50th and 75th percentiles as cut points (males: < 20, 20-29, 29-52 and > 52 U/l; females: < 13, 13-18, 18-25 and > 25 U/l). As compared with the first quartile, the relative risks of arterial stiffness were 1.418, 1.667 and 2.394 in the other three categories, respectively (test for trend P < 0.05). After adjustment in five models, serum γ-glutamyltransferase was still a risk factor of arterial stiffness. We found inverted U-shape curves in both genders and the third quartile (male: 29 52 U/l; female: 18-25 U/l) had the highest odds ratios of 1.640 and 1.529, respectively.

CONCLUSIONS

We demonstrated that high serum γ-glutamyltransferase concentrations were directly associated with the increased risk of arterial stiffness, in general, and with peripheral polyneuropathy in subjects with diabetes in an ethnic She Chinese population. Alcohol use, gender, BMI and blood pressure were related to serum γ-glutamyltransferase and were involved in the relationship between serum γ-glutamyltransferase and brachial-ankle pulse-wave velocity.

The Global Burden of Cardiovascular Disease: The Role of Endothelial Function and Arterial Elasticity in Cardiovascular Disease as Novel and Emerging Biomarkers

Some consider the measurements of arterial elasticity and flow-mediated dilation to be an indirect "biomarker" of endothelial dysfunction. As such, we describe the various uses of these techniques in the evaluation of the natural history of vascular disease. These measures are potential markers of disease, as abnormalities reflect changes in the integrity of vascular structure but occur prior to the manifestation of symptomatic cardiovascular events. In this review, the natural history of arterial elasticity is discussed, and the effects of aging and inflammation are reviewed. The role that arterial elasticity and flow-mediated dilation have in predicting future cardiovascular disease, and the effects of pharmacologic agents on these measures, is also reviewed.

Serum gamma glutamyl transferase: a novel biomarker for screening of premature coronary artery disease

BACKGROUND

We aimed to elucidate the association between gamma glutamyl transferase (GGT) activity with prevalence of premature coronary artery disease (CAD) in young Pakistani patients undergoing diagnostic coronary angiography.

METHODS

A total of 218 young adults (age ≤ 45 years) underwent diagnostic angiography. Serum samples were taken from all the patients and analyzed for serum GGT activity, cholesterol and triglycerides.

RESULTS

Coronary artery disease patients had significantly increased GGT activity (P = .001) and exhibited a significant positive correlation with blood pressure, cholesterol, blood glucose, and smoking and negative correlation with total antioxidant status (P < .01).

CONCLUSION

The study revealed good diagnostic accuracy at cutoff of 35 U/L with a sensitivity of 92%, specificity of 81%, and diagnostic odds ratio of 48 in estimation of premature CAD in young Pakistanis.

Serum gamma-glutamyl transferase and risk of heart failure in the community

OBJECTIVE

To examine the association of serum gamma-glutamyltransferase (GGT) with incident heart failure.

METHODS AND RESULTS

We related serum GGT to the incidence of heart failure in 3544 (mean age, 44.5 years; 1833 women and 1711 men) Framingham Study participants who were free of heart failure and myocardial infarction. On follow-up (mean, 23.6 years), 188 participants (77 women) developed new-onset heart failure. In multivariable Cox proportional hazards regression models adjusting for standard risk factors and alcohol consumption as time-varying covariates (updated every 4 years), each SD increase in log-GGT was associated with a 1.39-fold risk of heart failure (95% CI, 1.20 to 1.62). The linearity of the association was confirmed by multivariable-adjusted splines, and the relations remained robust on additional adjustment for hepatic aminotransferases and C-reactive protein. Participants with a serum GGT level at the median or greater had a 1.71-fold risk of heart failure (95% CI, 1.21 to 2.41) compared with individuals with GGT concentrations less than the median. GGT marginally increased the model C-statistic from 0.85 to 0.86 but improved the risk reclassification modestly (net reclassification index, 5.7%; P=0.01).

CONCLUSIONS

In this prospective study of a large community-based sample, higher serum GGT concentrations within the "normal" range were associated with greater risk of heart failure and incrementally improved prediction of heart failure risk.

The importance of gamma-glutamyltransferase activity in patients with coronary artery disease

BACKGROUND

In this study, we sought to investigate the relation of gamma-glutamyltransferase (GGT) levels with the significance of coronary artery disease (CAD), clinical presentation, left ventricular (LV) function, and inflammatory activity.

METHODS

A total of 235 patients (mean age: 60.1 +/- 10.5 years, 166 [70%] males) who had coronary angiography were included in the study. Patients who had CAD constituted the study group (Group 1, n=189) and patients who had insignificant coronary disease or normal coronary activity constituted the control group (Group 2, n=46).

RESULTS

GGT levels were higher in Group 1 than Group 2 (38.7 +/- 30.9 U/L versus 27.5 +/- 17.5 U/L, p =0.025). Left ventricular ejection fraction (LVEF) was lower in Group 1 than Group 2 (52.6% +/- 11.7% versus 58.8% +/- 11.3%, p < 0.002). GGT activity (40.2 +/- 32.5 U/L versus 29.1 +/- 18.3 U/L, p < 0.002) and c-reactive protein (CRP) levels (33.9 +/- 43.6 mg/dl versus 17.8 +/- 29.8 mg/dl, p < 0.002) were higher, LVEF (52.6% +/- 12.1% versus 56.5% +/- 11.0%, p =0.021) was lower in patients with acute coronary syndrome compared with stable CAD group. In regression analysis, CRP levels (p < 0.0001, odds ratio [OR]=3.77, 95% confidence interval [CI] 0.10 < OR < 0.32), LVEF (p =0.016, OR=- 2.44, 95% CI - 0.95 < OR < - 0.10) and LV end-diastolic pressure (p =0.015, OR=4.31, 95% CI - 1.19 < OR < - 0.13) were independent predictors of GGT activity.

CONCLUSIONS

The increased GGT activity is related to LV function, clinical stability, and inflammatory activity rather than the severity of CAD. Measurement of GGT activity may be useful in predicting cardiovascular risk.

Inflammation as a cardiovascular risk factor and pulse wave velocity as a marker of early-stage atherosclerosis in the Japanese population

Inflammation and pulse wave velocity (PWV) are a potential risk factor and marker, respectively, for atherosclerosis in the primary prevention setting. Atherosclerosis is now generally accepted to be an inflammatory disorder of the arterial wall, and the high-sensitivity C-reactive protein (hs-CRP) level has been reported to be a strong predictor of cardiovascular events. High-sensitivity-CRP is associated with two factors related to inflammation: (1) the local production of CRP by atheromatous tissue or coronary artery smooth muscle cells and (2) adipose tissue as a potent source of inflammatory cytokines. Based on studies in North America and Europe, hs-CRP has been established as a cardiovascular risk factor and a cut-off value has been recommended. However, Japanese have lower hs-CRP values than their Western counterparts, partly because Japanese have a lower body mass index (BMI), which correlates positively to hs-CRP, and partly because lifestyle and genetic factors can affect hs-CRP values. Therefore, a cut-off value needs to be established by cohort studies for the Japanese population. Carotid-femoral PWV is most commonly measured by applanation tonometry, particularly in Europe, but this method is critically dependent upon the accurate placing of transducers over the arteries and is both time-consuming and complex. A novel device has been recently developed in Japan that measures brachial-ankle PWV (baPWV) using a volume-rendering method. Brachian-ankle PWV is a suitable screening method because of its technical simplicity and shorter measurement time. It is associated not only with conventional cardiovascular risk factors but also with new risk factors, such as inflammation, gamma-glutamyltransferase, chronic kidney disease, and psychosocial factors. However, a suitable cut-off value has yet to be established.

Aortic stiffness in untreated adult patients with human immunodeficiency virus infection

HIV infection is associated with chronic immune activation, subclinical inflammation, and an atherogenic metabolic profile. It remains controversial whether HIV infection is a risk factor for accelerated arteriosclerosis independent from the effects of antiretroviral drugs. We investigated whether aortic stiffness, an early marker of arteriosclerosis, is increased in HIV patients who were not under antiretroviral treatment. In 39 untreated HIV-infected patients and 78 individually matched age-, sex-, and blood pressure-matched HIV-uninfected control subjects, we determined aortic pulse wave velocity (PWV), a direct noninvasive measure of aortic stiffness, by tonometric method. Subjects with overt cardiovascular disease or major cardiovascular risk factors were excluded from the study. Prevalence of the metabolic syndrome was higher in HIV patients (18% versus 5%; P=0.025). HIV patients had a higher aortic PWV (7.5+/-1.4 versus 6.7+/-1.1 m.s(-1); P=0.001) than control subjects. Age, mean arterial pressure as a measure of distending pressure, and HIV infection (all P<0.05) independently predicted aortic PWV when a consistent number of cardiovascular risk factors was simultaneously controlled for. Among HIV-infected subjects, serum gamma-glutamyl transpeptidase concentration (beta=0.46; P=0.003) and mean arterial pressure (beta=0.32; P=0.03) were independent determinants of aortic PWV. In conclusion, aortic stiffness is increased in HIV-infected individuals who have never received antiretroviral therapy. PWV increases with increasing serum gamma-glutamyl transpeptidase concentration. Our data support the hypothesis that HIV infection is a risk factor for arteriosclerosis.