Serum gamma-glutamyl transferase and mortality in persons undergoing coronary angiography—The Ludwigshafen Risk and Cardiovascular Health Study

Association Between Gamma-Glutamyl Transferase, Total Bilirubin and Systemic Lupus Erythematosus in Chinese Women

Background

Systemic lupus erythematosus (SLE) affects many organs and systems of the human organism, at present, its specific pathogenesis is not completely clear, but inflammation is considered to be an important factor involved in the pathogenesis and progression of SLE. Gamma-glutamyl transpeptidase (GGT) and total bilirubin (TBIL) have different effects on inflammation: GGT has pro-inflammatory effects, on the contrary, TBIL has anti-inflammatory effects. Study has found that GGT and TBIL play opposite roles in metabolic diseases. However, the roles of them in SLE are unknown. Meanwhile, the relationship between GGT and SLE also remains unexplored.

Method

We recruited 341 SLE patients and 332 healthy individuals in Liaocheng People’s Hospital from August 2018 to May 2019. We diagnosed SLE using 2019 revised American College of Rheumatology (ACR) SLE criteria, and modeled the study outcomes using logistic regression to explore the respective relationship between GGT, TBIL and SLE. We also analyzed the interaction of GGT and TBIL in the progression of SLE.

Results

We found that the levels of CRP, IL-6 and TNF-α in the aggravated group were significantly higher than those in the unaggravated group, the levels of C3 and C4 in the aggravated group were significantly lower than those in the unaggravated group. According to Spearman correlation analysis, GGT is proportional to CRP (r_s=0.417) and IL-6 (r_s=0.412), inversely proportional to C3 (r_s=-0.177) and C4 (r_s=0.-132). TBIL was inversely proportional to CRP (r_s=-0.328) and TNF(r_s=-0.360), and positively proportional to C3 (r_s=0.174) and C4 (r_s=0.172). In the fully adjusted model, compared to the lowest quartile, the highest quartile of GGT exhibited a positive association with the risk of SLE aggravation (OR=2.99, 95% CI: 1.42–6.31, P<0.001). At the same time, compared to the highest quartile, the quartile lowest of TBIL exhibited a positive association with the risk of SLE aggravation (OR=2.66, 95% CI: 1.27–5.59, P<0.001) in the fully adjusted model. Through interaction analysis, we found that women with high GGT levels had an increased risk of SLE aggravation when they had a low level of TBIL (OR=3.68, 95% CI: 1.51–9.01, for women with Q1 TBIL and Q4 GGT compared to women with Q2-Q4 TBIL and Q1-Q3 GGT, P for interaction <0.001), the combined AUC value (AUC_COMBINED=0.711) of high GGT level and TBIL were higher than their respective values (AUC_GGT=0.612, AUC_TBIL=0.614).

Conclusion

We found that the effects of GGT and TBIL in the progression of SLE are opposite. High GGT level might be a risk factor for SLE aggravation, as GGT levels increased, so did the risk of SLE aggravation. At the same time, we found that low TBIL level might be a risk factor for SLE aggravation. Moreover, high GGT level and low TBIL level had a subadditive effect on the increased risk of SLE aggravation.

Association Between γ-Glutamyltransferase Level and Cardiovascular or All-Cause Mortality in Patients With Coronary Artery Disease: A Systematic Review and Meta-Analysis

This meta-analysis assessed the prognostic value of serum γ-glutamyltransferase (GGT) level for cardiovascular (CV) and all-cause mortality in patients with coronary artery disease (CAD). We conducted a systematic literature search of PubMed, Web of Science, Embase, China National Knowledge Infrastructure, Wanfang, and Weipu databases until December 2018. Observational studies investigating the prognostic role of serum GGT level for CV and all-cause mortality in patients with CAD were included. Pooled risk ratios (RR) with 95% confidence intervals (CI) for the highest versus the lowest GGT level were used to summarize the prognostic value. Twelve studies involving 12 531 patients with CAD were included. Meta-analysis showed that elevated GGT level was significantly associated with higher risk of CV mortality (RR: 2.04; 95% CI: 1.57-2.64) and all-cause mortality (RR: 1.49; 95% CI: 1.27-1.74) in patients with CAD. This meta-analysis suggests that elevated serum GGT levels are an independent predictor of CV and all-cause mortality in patients with CAD. Determination of GGT level may improve the prediction of CV and all-cause mortality in patients with CAD.

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.

Gamma-glutamyl transferase and prognosis in patients with coronary artery disease

BACKGROUND

The association between gamma-glutamyl transferase (GGT) activity and outcome of patients with coronary artery disease (CAD) remains poorly investigated.

METHODS

The study included 5501 patients with CAD treated with percutaneous coronary intervention and GGT measurements available. The primary outcome was 3-year mortality.

RESULTS

GGT activity tertiles were: 1st tertile (GGT<28.10U/L; n=1866), 2nd tertile (GGT≥28.10U/L to49.50U/L; n=1804) and 3rd tertile (GG>49.50U/L; n=1831). There were 110 deaths in the 1st, 111 deaths in the 2nd and 216 deaths in the 3rd GGT tertile (mortality estimates, 7.1%, 7.2% and 13.9%; P<0.001). GGT was independently associated with the increased risk of 3-year all-cause (adjusted hazard ratio [HR]=1.30, 95% confidence interval [CI] 1.18 to 1.44, P<0.001), cardiac (HR=1.21 [1.06-1.39], P=0.005) and non-cardiac (HR=1.42 [1.23-1.63], P<0.001) mortality (all risk estimates calculated per standard deviation increase in the log GGT activity). GGT improved prediction of all-cause (P<0.001) and non-cardiac mortality (P<0.001) but not cardiac mortality (P=0.155).

CONCLUSIONS

In patients with CAD, elevated GGT activity is associated with increased risk of 3-year all-cause, cardiac and non-cardiac mortality. GGT provided incremental prognostic information on top of cardiovascular and metabolic risk factors for prediction of all-cause and non-cardiac mortality but not cardiac mortality.

Serum Gamma-Glutamyltransferase Levels Predict Mortality in Patients With Peritoneal Dialysis

Serum gamma-glutamyltransferase (GGT) level has been considered marker of oxidative stress as well as liver function. Serum GGT level has been reported to be associated with the mortality in hemodialysis patients. However, it is not well established whether serum GGT level is associated with all-cause mortality in peritoneal dialysis (PD) patients. The aim of this study was to determine the association between serum GGT levels and all-cause mortality in PD patients.PD patients were included from the Clinical Research Center registry for end-stage renal disease cohort, a multicenter prospective observational cohort study in Korea. Patients were categorized into 3 groups by tertile of serum GGT levels as follows: tertile 1, GGT < 16 IU/L; tertile 2, GGT = 16 to 27 IU/L; and tertile 3, GGT > 27 IU/L. Primary outcome was all-cause mortality.A total of 820 PD patients were included. The median follow-up period was 34 months. Kaplan-Meier analysis showed that the all-cause mortality rate was significantly different according to tertiles of GGT (P = 0.001, log-rank). The multivariate Cox regression analysis showed that higher tertiles significantly associated with higher risk for all-cause mortality (tertile 2: hazard ratio [HR] 2.08, 95% confidence interval [CI], 1.17-3.72, P = 0.013; tertile 3: HR 1.83, 95% CI, 1.04-3.22, P = 0.035) in using tertile 1 as the reference group after adjusting for clinical variables.Our study demonstrated that high serum GGT levels were an independent risk factor for all-cause mortality in PD patients. Our findings suggest that serum GGT levels might be a useful biomarker to predict all-cause mortality in PD patients.

What does serum γ-glutamyltransferase tell us as a cardiometabolic risk marker?

γ-glutamyltransferase plays a key role in the synthesis and metabolism of extracellular glutathione, a major antioxidant in several defence mechanisms in the body. γ-glutamyltransferase is affected by environmental and genetic factors, and is raised when there is depletion of glutathione. Hence, it is a marker of oxidative stress. There is robust evidence that γ-glutamyltransferase even when values are within the reference interval is associated with increased cardiovascular and all-cause mortality in both sexes, in normal subjects and subjects with coronary artery disease, in the middle-aged and the elderly after adjusting for confounding factors. γ-glutamyltransferase even within the reference interval is associated with future presentation of type 2 diabetes, and the longitudinal increase in γ-glutamyltransferase activity is associated with increased risk of type 2 diabetes and cardiovascular mortality. γ-glutamyltransferase is associated with cardiovascular risk factors and metabolic syndrome. It has a prognostic value after a previous acute myocardial infarction and may be an indicator of adverse outcome in acute coronary syndromes and other chronic cardiac disorders. There is limited data about γ-glutamyltransferase and any association with peripheral arterial disease and also whether knowing γ-glutamyltransferase activity improves cardiovascular risk prediction beyond conventional risk factors. γ-glutamyltransferase is present in atherosclerotic lesions in the coronary and carotid arteries, and has a prooxidant role leading to the production of reactive oxygen species and atherosclerosis. Current reference intervals for γ-glutamyltransferase are inappropriate and need to be addressed. Some laboratories still use non- International Federation of Clinical Chemistry methods for estimation of γ-glutamyltransferase which are associated with lower results. Such laboratories should review their method and consider changing to the International Federation of Clinical Chemistry method.

Gamma glutamyl transferase and oxidative stress in obstructive sleep apnea: a study in 1744 patients

OBJECTIVE

We analyze a large population of patients to determine whether gamma glutamyl transferase (GGT) levels are increased in sleep apnea-hypopnea syndrome (OSA) and whether these levels are related to clinical characteristics or polygraphic indexes.

METHODS

A cross-sectional study in a population of 1744 patients referred for OSA suspicion was conducted. The following variables were determined: glucose, cholesterol, triglycerides, aspartate aminotransferase (GOT), alanine aminotransferase (GPT), GGT, body mass index, waist-hip ratio (WHR), and overnight sleep study.

RESULTS

The 483 patients with GGT ≥40 IU/l were younger and more obese, and had a pattern of more centrally distributed fat than the 1261 with GGT <40 IU/l. Patients with high levels of GGT also consumed more alcohol, had a poorer biochemical profile, and had more respiratory and oximetric alterations during sleep. GGT levels were significantly correlated with AHI, DI, and CT90. In the binary regression test, WHR, glucose, cholesterol, triglycerides, and grams of alcohol consumed per day predicted GGT levels ≥40 IU/l, while none of the polygraphic variables had predictive value.

CONCLUSIONS

High GGT levels were associated with the severity of OSA. However, this relationship seems to be due to the coexistence of other associated factors, mainly central obesity, rather than to the respiratory disorders found in this disease.

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Gamma-glutamyl transpeptidase level associated with metabolic syndrome and proinflammatory parameters in the young Roma population in eastern Slovakia: a population-based study

BACKGROUND

Elevated gamma-glutamyl transpeptidase (GGT) is present approximately in half of all patients with non-alcoholic fatty liver disease (NAFLD). NAFLD is the liver manifestation of metabolic syndrome (MS). This study aimed to explore the relationship between GGT and MS or proinflammatory parameters.

METHODS

Data from the cross-sectional HepaMeta study conducted in Slovakia in 2011 among Roma living in rural communities were used. Participants (n = 446) were divided into 2 groups; those with elevated GGT and those with normal GGT levels. MS was diagnosed according to the International Diabetes Federation criteria; presence of central obesity and low density lipoproteins (LDL) or high density lipoproteins (HDL), high triglycerides, hypertension, glucose intolerance or type 2 diabetes. Participants were tested for the presence of MS and its components, and biochemical tests for lipid levels (total cholesterol, HDL, LDL, TG) and inflammatory parameters (high sensitivity C-reactive protein--hs-CRP and ferritin) were performed.

RESULTS

Of 446 Roma participants, only 29 (6.5%) had GGT levels above the normal value. After exclusion of patients with viral hepatitis and alcohol abuse, patients with elevated GGT suffered from MS more often (p < 0.001), and patients with more MS components had a higher risk of elevated GGT. We found a significant association between GGT and the individual MS components, except HDL (waist circumference > or = 94 cm in men or 80 cm in women: p < 0.01; BMI > 30: p < 0.001; fasting glucose > or = 5.6 mmol/l: p < 0.001; arterial hypertension: p < 0.05, and TAG > or = 1.7 mmol/l: p < 0.001). Patients with elevated GGT levels had also significantly higher hs-CRP (hs-CRP > 2 mg/l: p < 0.001; hs-CRP > 3 mg/l: p < 0.001) and ferritin (ferritin > 300 mg/l: p < 0.01) levels.

CONCLUSION

Patients with MS have more significantly elevated levels of GGT. There is a significant association of GGT with individual MS components, except HDL and inflammatory parameters (hs-CRP, ferritin).

Assessment of plasma aminothiol levels and the association with recurrent atherothrombotic events in patients hospitalized for an acute coronary syndrome: a prospective study

BACKGROUND

The aminothiols homocysteine and, to a lesser extent, cysteine have been associated with adverse cardiovascular outcome, whereas glutathione, as an antioxidant, may protect against atherosclerosis and thrombosis. Potentially, the combined assessment of these aminothiols may provide a more accurate association with future cardiovascular outcome. We evaluated the association between recurrent atherothrombotic events and the concentration of total plasma cysteine, homocysteine, and glutathione and their combination.

METHODS

Respective aminothiols were measured by high-performance liquid chromatography in blood plasma of consecutive first-day survivors admitted for an acute coronary syndrome between April 2002 and January 2004. The combined score was calculated using the combination of the individual aminothiols. The end point was the composite of cardiovascular death, myocardial infarction, and/or stroke.

RESULTS

A cohort of 375 consecutive patients (median age 66 years, 66% male) were followed for a median duration of 2.7 years. The end point occurred in 82 patients (22%). In univariate analyses, all aminothiols were significantly associated with the composite end point. After correction for possible confounders, only cysteine and glutathione remained significantly associated. The strongest association with the end point was observed for the combined score (adjusted hazard ratio, 1.40 per standard deviation increase; p=0.005).

CONCLUSIONS

Although homocysteine is generally considered the aminothiol of interest with respect to cardiovascular disease, in our prospective study, only cysteine and glutathione appeared independently associated with recurrent atherothrombotic events. Moreover, we showed that an imbalance in the combination of aminothiols could be of more importance than investigating the individual metabolites.

Gamma-glutamyltransferase predicts increased risk of mortality: a systematic review and meta-analysis of prospective observational studies

The aim of this study was to evaluate the association between gamma-glutamyltransferase (GGT) and mortality through a comprehensive analysis of existing evidence. PubMed, Embase, Chinese Biomedical Literature, and Science Citation Index databases were electronically searched. Studies were included if the study design was prospective and included reference and at-risk levels of GGT at baseline and mortality as a separate outcome. The quality of the studies included was assessed on the basis of Newcastle-Ottawa scale. Data from selected qualified studies were systematically reviewed, pooled, and analyzed according to the MOOSE guidelines and PRISMA statement. The results included the following: 1. 35 studies including 571,511 participants and 72,196 cases of mortality; 2. GGT, even at physiologic levels, was associated with increased all-cause mortality and cardiovascular mortality, and might also be associated with cancer-related mortality in the general population; and 3. GGT was very likely to be associated with all-cause mortality and cardiovascular mortality in patients with coronary artery disease and type 2 diabetes mellitus. Many of the studies included did not specifically exclude subjects with hepatic diseases or alcohol abuse, which may have obscured the results. Moderate heterogeneity was observed in the meta-analysis of GGT and all-cause mortality. Different compositions of cause-specific mortality might be the reason. However, subgroup analysis could only be performed on cardiovascular death because of insufficient information. GGT, even at physiologic high levels, predicted mortality, especially cardiovascular mortality and cancer mortality. The underlining mechanism and potential effects of GGT-targeted intervention on health warrant further investigation.

Glycerophospholipid and sphingolipid species and mortality: the Ludwigshafen Risk and Cardiovascular Health (LURIC) study

Vascular and metabolic diseases cause half of total mortality in Europe. New prognostic markers would provide a valuable tool to improve outcome. First evidence supports the usefulness of plasma lipid species as easily accessible markers for certain diseases. Here we analyzed association of plasma lipid species with mortality in the Ludwigshafen Risk and Cardiovascular Health (LURIC) study. Plasma lipid species were quantified by electrospray ionization tandem mass spectrometry and Cox proportional hazards regression was applied to assess their association with total and cardiovascular mortality. Overall no differences were detected between total and cardiovascular mortality. Highly polyunsaturated phosphatidylcholine species together with lysophosphatidylcholine species and long chain saturated sphingomyelin and ceramide species seem to be associated with a protective effect. The predominantly circulating phosphatidylcholine-based as well as phosphatidylethanolamine-based ether species and phosphatidylethanolamine species were positively associated with total and cardiovascular mortality. Saturated and monounsaturated phosphatidylcholine species, especially phosphatidylcholine 32∶0 (most probably dipalmitoyl-phosphatidylcholine) and palmitate containing sphingomyelin and ceramide species showed together with 24∶1 containing sphingomyelin and ceramide species strongest positive association with mortality. A quotient of the sums of the six most protective species and the six species with the strongest positive mortality association indicated an almost 3-fold increased risk of mortality, which was higher than the hazard ratio for known risk factors in our cohort. Plasma lipid species levels and especially ratios of certain species may be valuable prognostic marker for cardiovascular and total mortality.

The fatty liver index is associated with increased mortality in subjects referred to coronary angiography

BACKGROUND AND AIMS

Fatty liver index (FLI), a surrogate parameter for nonalcoholic fatty liver disease, is an emerging risk factor for cardiovascular diseases and mortality. We aimed to evaluate whether FLI is associated with all-cause, cardiovascular, and non-cardiovascular mortality as well as fatal cancer in a cohort of subjects routinely referred to coronary angiography.

METHODS AND RESULTS

FLI was calculated using BMI (body mass index), waist circumference (WC), triglycerides (TG) and gamma-glutamyl transferase (GGT) in 3270 subjects who were referred to coronary angiography (1997-2000). The main outcome measures were Cox proportional hazard ratios (HRs) for mortality from all causes, cardiovascular causes, non-cardiovascular causes, and fatal cancer. After a median follow-up time of 7.7 years, 740 subjects (22.6%) had died. There were 437 deaths due to cardiovascular disease and 303 deaths due to non-cardiovascular disease. Age-, sex-, and BMI-adjusted HRs (with 95% confidence intervals) for all-cause, cardiovascular, and non-cardiovascular mortality in the highest compared to the lowest FLI quartile were 2.56 (1.90-3.43; p < 0.001), 2.17 (1.47-3.22; p < 0.001), and 3.49 (2.16-5.66; p < 0.001), respectively. In age-, sex-, and BMI-adjusted analyzes, we found no significant association of FLI with fatal cancer. Multivariate adjusted HRs for all-cause, cardiovascular, non-cardiovascular mortality, and fatal cancer in the highest compared to the lowest FLI quartile were 2.17 (1.58-2.99; p < 0.001), 1.64 (1.07-2.51; p = 0.023), 3.72 (2.22-6.24; p < 0.001), and 2.33 (1.01-5.41; p = 0.048) respectively.

CONCLUSION

In subjects referred to coronary angiography, high FLI levels are independently associated with increased all-cause, cardiovascular, and non-cardiovascular mortality as well as fatal cancer.

γ-Glutamyl transferase activity and the burden of coronary atherosclerosis in patients with ST-segment elevation myocardial infarction

The relationship between extent, severity, and complexity of coronary artery disease (CAD) in patients with ST-segment elevation myocardial infarction (STEMI) and serum γ-glutamyl transferase (GGT) activity has not been adequately studied. We evaluated the relationship between GGT activity and the burden of CAD as assessed by SYNTAX score (SXscore) in patients with STEMI. A total of 243 patients (age 67.1 ± 8.6, 77.4% male) with STEMI were divided into 2 groups. Low- and high-SXscore groups were defined as SXscore <22 and ≥22, respectively. Admission GGT activities were similar between low- and high-SXscore groups (32 ± 17 vs 33 ± 18; P = .625), and there was no significant correlation between GGT activity and SXscore. Although there was an association between high SXscore and major adverse cardiovascular events, as expected, our results did not demonstrate any relationship between admission GGT activities and complexity and extent of the coronary lesions in patients with STEMI.

Gamma-glutamyltransferase is associated with cardiovascular and all-cause mortality: a meta-analysis of prospective cohort studies

OBJECTIVE

The purpose of the present study was to investigate whether gamma-glutamyltransferase (GGT) is an independent predictor for future cardiovascular (CV) and all-cause mortality with prospective observational studies by meta-analysis.

METHODS

Electronic literature databases (Cochrane Library, Medline, and Embase) were searched for relevant prospective observational studies on the association between baseline GGT and CV and all-cause mortality published prior to June 2012. Pooled adjust relative risk (RR) and corresponding 95% confidence intervals(CI) were calculated separately for categorical risk estimates(highest vs. lowest GGT quartile) and continuous risk estimates (per unit-log GGT increment).

RESULTS

Seven studies with 273,141 participants were identified and analyzed. The pooled RR of CV mortality for highest vs. lowest GGT quartile was 1.52 (95% CI 1.36-1.70). The pooled RR of CV mortality for per unit-log (GGT) increment was 1.76 (95% CI 1.60-1.94). The pooled RR for all-cause mortality for highest vs. low GGT quartile was 1.56 (95% CI 1.34-1.83). Subgroup analyses based on region, gender, follow-up duration, and sample size showed that the positive association between GGT and risk of CV mortality was consistently observed in each subgroup except for the Asia subgroup (RR=1.59, 95% CI 0.76-3.30).

CONCLUSIONS

GGT is an independent predictor for future CV mortality and all-cause mortality, and might be independent of alcohol intake.

The prognostic value of serum gamma glutamyl transferase activity on admission in patients with STEMI undergoing primary PCI

We assessed the association between serum gamma glutamyl transferase (GGT) activity with postprimary percutaneous coronary intervention (PCI) coronary flow and in-hospital major advanced cardiac events (MACEs) in patients with ST elevation myocardial infarction (STEMI). Patients with STEMI (n = 425; males 78%; mean age 60 ± 13 years) were enrolled. Patients were divided into 3 GGT tertiles and 2 groups according to thrombolysis in myocardial infarction (TIMI) flow grade. The TIMI flow percentages were similar in the 3 GGT tertiles (32%, 45%, and 42%, respectively, P = .336). Total MACE increased with GGT tertiles (among tertiles, respectively; P < .001). The total MACE was significantly higher in impaired flow group than in normal flow group (23% vs 7%; P < .001). At multivariate analyses, serum GGT activity was an independent predictor of in-hospital MACE (odds ratio [OR] 1.12, 95% confidence interval [CI] 1.01-1.33; P < .001). In conclusion, serum GGT activity is associated with in-hospital MACE in patients with STEMI undergoing primary PCI.

The prognostic role of gamma-glutamyltransferase activity in non-diabetic ST-elevation myocardial infarction

In patients with acute coronary syndrome, gamma-glutamyltransferase activity (GGT) proved to be an independent predictor of the development of major adverse cardiac events at early and long terms. No data are available on GGT in ST-elevation myocardial infarction (STEMI). We assessed, in 337 consecutive STEMI patients without previously known diabetes submitted to mechanical revascularization, the prognostic role of GGT for in-Intensive Cardiac Care Unit mortality, together with the relation(s) between GGT and acute glucose dysmetabolism (admission glycemia, peak glycemia, insulin resistance as indicated by the Homeostatic Model Assessment HOMA index). At logistic regression analysis, GGT was an independent predictor for in-ICU mortality (OR 1.01 (95% CI 1.003-1.013) p = 0.002), when adjusted for BMI and for major bleedings [(OR 1.005 (95% CI 1.001-1.009) p = 0.029]. At linear regression analyses, GGT was significantly correlated with admission glycemia (r = 0.172; p = 0.002), uric acid (r = 0.146; p = 0.011), insulin (r = 0.171; p = 0.002) and age (r = -0.129; p = 0.020). We document that in STEMI patients without previously known diabetes submitted to mechanical revascularization, GGT values are an independent predictor of early mortality. The significant correlation between GGT and acute glucose dysmetabolism (as indicated by admission glycemia and insulin-resistance) can account, at least in part, for the prognostic role of GGT.

Prevalence of Metabolic Syndrome According to Different Definitions in a Hypertensive Population

Aims: The metabolic syndrome (MetS) is associated with increased risk of cardiovascular disease (CVD) and diabetes mellitus (DM). Several definitions of MetS have been proposed. The aim of the present study was to estimate and compare the prevalence of MetS according to the National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III), American Heart Association-National Heart Lung and Blood Institute (AHA-NHLBI), International Diabetes Federation (IDF) and the more recent Joint Interim Statement (JIS) definitions in patients attending a hypertension clinic. Methods: The records of patients referred to the hypertension clinic at the University Hospital (Heraklion, Crete) from January 2001 to June 2009 were screened retrospectively. A total 384 patients (146 men) were included in the study. Results: The prevalence of MetS according to the IDF and JIS definitions was significantly higher compared with that of the NCEP ATP III in both genders (IDF: P = .009 and P = .002, JIS: P = .002 and P = 0.001 for men and women, respectively); this was the case for the AHA-NHLBI definition only among women ( P = .03). All MetS components differed significantly ( P from < .0001 to .02) between patients with and without MetS for all definitions. Conclusions: The prevalence of MetS varies considerably depending on the definition used in a hypertensive population in a Mediterranean country. These differences will influence risk assessment.

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.

Use of a Mendelian randomization approach to assess the causal relation of gamma-Glutamyltransferase with blood pressure and serum insulin levels

Elevated levels of γ-glutamyltransferase (GGT) have been associated with elevated blood pressure (BP) and diabetes. However, the causality of these relations has not been addressed. The authors performed a cross-sectional analysis (2003-2006) among 4,360 participants from the population-based Cohorte Lausannoise (CoLaus) Study (Lausanne, Switzerland). The rs2017869 variant of the γ-glutamyltransferase 1 (GGT1) gene, which explained 1.6% of the variance in GGT levels, was used as an instrument for Mendelian randomization (MR). Sex-specific GGT quartiles were strongly associated with both systolic and diastolic BP (all P's < 0.0001). After multivariable adjustment, these relations were attenuated but remained significant. Using MR, the authors observed no positive association of GGT with BP (systolic: β -5.68, 95% confidence interval (CI): -11.51, 0.16 (P = 0.06); diastolic: β = -2.24, 95% CI: -5.98, 1.49 (P = 0.24)). The association of GGT with insulin was also attenuated after multivariable adjustment but persisted in the fully adjusted model (β = 0.07, 95% CI: 0.04, 0.09; P < 0.0001). Using MR, the authors also observed a positive association of GGT with insulin (β = 0.19, 95% CI: 0.01, 0.37; P = 0.04). In conclusion, the authors found evidence for a direct causal relation of GGT with fasting insulin but not with BP.

Interplay of the inflammatory and stress systems in a hepatic cell line: interactions between glucocorticoid receptor agonists and interleukin-6

The liver plays an important role in inflammation and stress by producing the acute phase proteins (APPs) required for resolution of inflammation as well as by delivering systemic glucose, through gluconeogenesis, required to fuel the stress response. Disruption of the interplay between interleukin 6 (IL-6) and glucocorticoids (GCs), the peripheral mediators of inflammation and stress, respectively, may lead to side-effects associated with the pharmacological use of GCs. The current study investigated the interplay between IL-6 and GCs in a hepatoma cell line (BWTG3) at protein (protein activity assays, Western blotting, and ELISA) and mRNA (qPCR) levels. Specifically, the action of dexamethasone (Dex), a known antiinflammatory drug and glucocorticoid receptor (GR) agonist, is compared to that of Compound A (CpdA), a selective glucocorticoid receptor agonist (SEGRA). CpdA, like IL-6, but unlike Dex, increases GR binding and decreases the metabolic enzymes, tyrosine aminotransferase, phosphoenolpyruvate carboxykinase, and gamma glutamyltransferase, at protein or mRNA level. Like Dex, both CpdA and IL-6 increase the positive APPs, serum amyloid A and C-reactive protein, and decrease the negative APP, corticosteroid binding globulin. The study shows that the GC, Dex, and IL-6 generally have divergent effects on the GR and metabolic enzymes, while their functions are convergent on the APPs. In contrast to Dex, CpdA has effects convergent to that of IL-6 on the GR, metabolic enzymes, and APPs. Thus these findings suggest that CpdA, like Dex, modulates APPs, leading to effective control of inflammation, while, in contrast to Dex, it is less likely to lead to GC-induced side-effects.