Gamma-glutamyl transferase and cardiovascular disease

Effects of Heart Failure Therapies on Atrial Fibrillation: Biological and Clinical Perspectives

Heart failure (HF) and atrial fibrillation (AF) are prevalent cardiovascular diseases that contribute significantly to morbidity, mortality, hospitalisation, and healthcare costs. It is not uncommon for these conditions to coexist and have mutually reinforcing effects. A critical factor in the aetiology of these conditions is oxidative stress, driven by reactive oxygen species (ROS), which contributes to atrial remodelling and fibrosis. The recent introduction of new drugs for the treatment of heart failure has also had an impact on the management of atrial fibrillation due to their influence on oxidative stress. The objective of this review is to analyse the effects of these therapies, including their role in mitigating ROS, on the prevention and treatment of AF in HF patients.

Cellular and molecular mechanisms of hepatic ischemia-reperfusion injury: The role of oxidative stress and therapeutic approaches

Ischemia-reperfusion (IR) or reoxygenation injury is the paradoxical exacerbation of cellular impairment following restoration of blood flow after a period of ischemia during surgical procedures or other conditions. Acute interruption of blood supply to the liver and subsequent reperfusion can result in hepatocyte injury, apoptosis, and necrosis. Since the liver requires a continuous supply of oxygen for many biochemical reactions, any obstruction of blood flow can rapidly lead to hepatic hypoxia, which could quickly progress to absolute anoxia. Reoxygenation results in the increased generation of reactive oxygen species and oxidative stress, which lead to the enhanced production of proinflammatory cytokines, chemokines, and other signaling molecules. Consequent acute inflammatory cascades lead to significant impairment of hepatocytes and nonparenchymal cells. Furthermore, the expression of several vascular growth factors results in the heterogeneous closure of numerous hepatic sinusoids, which leads to reduced oxygen supply in certain areas of the liver even after reperfusion. Therefore, it is vital to identify appropriate therapeutic modalities to mitigate hepatic IR injury and subsequent tissue damage. This review covers all the major aspects of cellular and molecular mechanisms underlying the pathogenesis of hepatic ischemia-reperfusion injury, with special emphasis on oxidative stress, associated inflammation and complications, and prospective therapeutic approaches.

Serum Gamma Glutamyltransferase: A Biomarker for Identifying Postprandial Hypertriglyceridemia

Purpose

Elevated serum gamma-glutamyltranspeptidase (GGT) is an independent marker of the activation of systemic inflammation, while conditions associated with elevated triglyceride (TG) levels, such as type 2 diabetes, non-alcoholic fatty liver disease, obesity, and metabolic syndrome, are associated with an increased inflammatory burden. Moreover, serum liver enzymes (GGT, alanine aminotransferase [ALT], aspartate aminotransferase [AST], and alkaline phosphatase [ALP]) are associated with metabolic syndrome and its components, including hypertriglyceridemia. However, the relationship between liver enzymes and postprandial hypertriglyceridemia (PHTG) remains unclear. Therefore, in this study we conducted oral fat tolerance tests (OFTTs) to understand the differences in serum liver enzyme levels among individuals with different lipid tolerance levels and their correlation with PHTG.

Patients and Methods

 For the OFTT, we enrolled 202 non-diabetic volunteers whose fasting triglyceride (TG) levels were less than 1.7 mmol/L in this case-control study. The participants were categorized into two groups according to the TG levels at the 0- and 4-h OFTT: a postprandial normal TG (PNTG) group and a PHTG group. Routine fasting serum biochemical indices, liver enzyme (GGT, ALT, AST, and ALP) levels, and 0- and 4-h OFTT lipid levels were assessed.

Results

The PHTG group had significantly higher serum GGT and ALT levels and a lower AST/ALT ratio than those in the PNTG group. However, no significant difference was observed in AST and ALP levels compared with the PNTG group. After adjusting for major confounders, logistic regression analysis indicated a significant correlation between serum GGT and PHTG (odds ratio = 1.168, P < 0.001), but not with ALT level, AST level, AST/ALT ratio, and ALP level. The receiver operating characteristic curve analysis demonstrated that the serum GGT level was an effective predictor of PHTG.

Conclusion

Serum GGT levels are significantly associated with PHTG risk and serve as an effective biomarker for early identification.

Association of haemato-biochemical indices and blood composite ratios with microfilaridermia in Onchocerciasis patients

BACKGROUND

Onchocerciasis causes chronic systemic inflammation. Several studies have used markers such as haemato-biochemical indices to predict the occurrence of systemic inflammation. This study assessed the variability and predictability of haemato-biochemical indices and blood composite ratios (BCRs) in microfilariae positive (MF+) and microfilariae negative (MF-) subgroups of onchocercomata participants.

METHODS

One hundred and five (105) MF + and 34 MF- participants were retrospectively recruited into the study. Screening for the presence of O. volvulus microfilariae was done from skin snips taken from the left and right iliac crests of participants using established and approved protocols. Haematological and biochemical indices were measured using standard laboratory automated analyzers. Blood composite ratios (BCRs) were calculated as ratios of the absolute parameters involved.

RESULTS

A significantly increased total WBC, absolute eosinophil, eosinophil percent and absolute basophil were observed in the MF + participants compared to MF- participants. Reduced gamma-glutamyl transferase (GGT) with increased estimated glomerular filtration rate (eGFR) was significantly associated with MF + participants compared to MF- participants. BCRs were significantly higher for eosinophil-to-neutrophil ratio (ENR), eosinophil-to-monocyte ratio (EMR), eosinophil-to-basophil ratio (EBR) and eosinophil-to-lymphocyte ratio (ELR) in MF + participants compared to MF- participants. After multivariate adjustment, onchocercomata participants with increased eosinophil counts (aOR = 13.86, 95% CI [2.07-92.90], p = 0.007), ENR x10 (aOR = 1.42, 95% CI [1.05-1.93], p = 0.025), EMR (aOR = 2.64, 95% CI [1.25-5.60], p = 0.011), EBR (aOR = 1.07, 95% CI [1.01-1.10], p = 0.020) and ELR x10 (aOR = 1.69, 95% CI [1.14-2.51], p = 0.009) were more likely to have microfilaridermia.

CONCLUSIONS

Elevated eosinophil counts with higher ENR, EMR, EBR and ELR levels are significantly associated with microfilaridermia in onchocercomata participants. Combining BCRs with eosinophil count significantly led to an improvement in the conventional model for predicting microfilaridermia.

Circulating Metabolomic Associations with Neurocognitive Outcomes in Pediatric CKD

BACKGROUND

Children with CKD are at risk for impaired neurocognitive functioning. We investigated metabolomic associations with neurocognition in children with CKD.

METHODS

We leveraged data from the Chronic Kidney Disease in Children (CKiD) study and the Neurocognitive Assessment and Magnetic Resonance Imaging Analysis of Children and Young Adults with Chronic Kidney Disease (NiCK) study. CKiD is a multi-institutional cohort that enrolled children aged 6 months to 16 years with eGFR 30-90 ml/min per 1.73 m 2 ( n =569). NiCK is a single-center cross-sectional study of participants aged 8-25 years with eGFR<90 ml/min per 1.73 m 2 ( n =60) and matched healthy controls ( n =67). Untargeted metabolomic quantification was performed on plasma (CKiD, 622 metabolites) and serum (NiCK, 825 metabolites) samples. Four neurocognitive domains were assessed: intelligence, attention regulation, working memory, and parent ratings of executive function. Repeat assessments were performed in CKiD at 2-year intervals. Linear regression and linear mixed-effects regression analyses adjusting for age, sex, delivery history, hypertension, proteinuria, CKD duration, and glomerular versus nonglomerular diagnosis were used to identify metabolites associated with neurocognitive z-scores. Analyses were performed with and without adjustment for eGFR.

RESULTS

There were multiple metabolite associations with neurocognition observed in at least two of the analytic samples (CKiD baseline, CKiD follow-up, and NiCK CKD). Most of these metabolites were significantly elevated in children with CKD compared with healthy controls in NiCK. Notable signals included associations with parental ratings of executive function: phenylacetylglutamine, indoleacetylglutamine, and trimethylamine N-oxide-and with intelligence: γ -glutamyl amino acids and aconitate.

CONCLUSIONS

Several metabolites were associated with neurocognitive dysfunction in pediatric CKD, implicating gut microbiome-derived substances, mitochondrial dysfunction, and altered energy metabolism, circulating toxins, and redox homeostasis.

PODCAST

This article contains a podcast at https://dts.podtrac.com/redirect.mp3/www.asn-online.org/media/podcast/CJASN/2023_11_17_CJN0000000000000318.mp3.

Impact of a Food Rebalancing Program Associated with Plant-Derived Food Supplements on the Biometric, Behavioral, and Biological Parameters of Obese Subjects

Between 2021 and 2023, the Scientific Council of Dietplus®, a group specialized in overweight and obesity management, conducted a clinical study on 170 volunteer subjects with a BMI > 29 Kg/m2 consecutively recruited. The Dietplus® program comprises nutritional education, intensive, personalized coaching, and consuming food supplements rich in plant derivatives. The aim of this study was to assess the effect of the Dietplus® program on biometric, behavioral, and biological parameters. A control group of 30 obese patients was followed for a similar 12-week period. Mean weight loss reached 9 ± 2.1 kg in the Dietplus® test group versus a 1 ± 0.1 kg weight gain in the control group. Excess weight loss reached 33 ± 13%, and fat mass loss was 7.6% (p < 0.001); waist circumference was reduced by 30%. Quality of Life, Nutriscore, and Prochaska di Clemente scale significantly improved (p < 0.001). Biological parameters showed substantial improvements in the carbohydrate profile and insulin resistance (HOMA index) and in the lipid profile with lower plasma triglyceride (p < 0.01) and VLDL (p < 0.01) concentrations. Inflammatory parameters (orosomucoid, ultrasensitive C-reactive protein, and PINI indices) were also substantially reduced. These results indicate a substantial benefit in subjects who followed the Dietplus® program. (Dietplus® 116 Rue Robert Bunsen, 57460 Behren-lès-Forbach, France is active in France Belgium and Spain. Plant Derived Food Supplements are produced in France). Indeed, improvements were observed in all biometric, behavioral, and metabolic parameters.

Clinical analysis of 908 patients with aortic dissection under different Stanford types: A cross-sectional study

This study aims to investigate the difference of clinical characteristics and risk factors in aortic dissection (AD) of patients with 2 Stanford subtypes. A retrospective analysis was conducted on 908 patients admitted to Tongji Hospital from July 2019 to January 2021, and the aortic computed tomography angiography was used to clearly diagnose the artery dissection. Patient basic information as well as blood test indicators containing leukocytes, neutrophils, lymphocytes, hemoglobin, myoglobin, hypersensitive cardiac troponin, γ-glutamyl transferase, total cholesterol, triglyceride, high density lipoprotein, low density lipoprotein, ultrasensitive C-reactive protein, glucose were recorded and analyzed. There was no significant difference in gender, heart rate, smoking history, hypertension history and diabetes history between the 2 groups (P > .05), however, compared with type A patients, type B patients were older, and had a significantly higher frequency of alcohol consumption (P < .05); On laboratory tests, type A patients had significantly higher mean leukocytes and neutrophils (P < .05), and significantly lower frequency of reduced hemoglobin than type B patients (P < .05), although there was no statistical difference in lymphocyte, γ-glutamyl transferase, total cholesterol, triglyceride, high density lipoprotein, low density lipoprotein and glucose counts between the 2 groups. Additionally, type A patients had a significantly higher number of abnormal myoglobin, hypersensitive cardiac troponin and ultrasensitive C-reactive protein test results than type B patients (P < .05). The receiver operating characteristic curve analysis showed that the area under the curve for each parameter was 0.605 (0.538-0.673) for hemoglobin, 0.610 (0.543-0.677) for leukocytes and 0.627 (0.561-0.693) for neutrophils. Understanding the relevant clinical indicators and risk factors of patients with different types of AD can provide a new perspective to assist the classification and diagnosis of AD and a basis for effective and rational treatment.

Development and comparison of machine learning-based models for predicting heart failure after acute myocardial infarction

AIMS

Heart failure (HF) is one of the common adverse cardiovascular events after acute myocardial infarction (AMI), but the predictive efficacy of numerous machine learning (ML) built models is unclear. This study aimed to build an optimal model to predict the occurrence of HF in AMI patients by comparing seven ML algorithms.

METHODS

Cohort 1 included AMI patients from 2018 to 2019 divided into HF and control groups. All first routine test data of the study subjects were collected as the features to be selected for the model, and seven ML algorithms with screenable features were evaluated. Cohort 2 contains AMI patients from 2020 to 2021 to establish an early warning model with external validation. ROC curve and DCA curve to analyze the diagnostic efficacy and clinical benefit of the model respectively.

RESULTS

The best performer among the seven ML algorithms was XgBoost, and the features of XgBoost algorithm for troponin I, triglycerides, urine red blood cell count, γ-glutamyl transpeptidase, glucose, urine specific gravity, prothrombin time, prealbumin, and urea were ranked high in importance. The AUC of the HF-Lab9 prediction model built by the XgBoost algorithm was 0.966 and had good clinical benefits.

CONCLUSIONS

This study screened the optimal ML algorithm as XgBoost and developed the model HF-Lab9 will improve the accuracy of clinicians in assessing the occurrence of HF after AMI and provide a reference for the selection of subsequent model-building algorithms.

Sex-specific associations of γ-glutamyltransferase to HDL-cholesterol ratio and the incident risk of cardiovascular disease: three Korean longitudinal cohorts from different regions

Background

The combination of gamma-glutamyl transferase (GGT) and high-density lipoprotein cholesterol (HDL-C) (GGT/HDL-C) is a novel noninsulin-based marker for assessing the risk of nonalcoholic fatty liver disease and type 2 diabetes mellitus. However, whether the GGT/HDL-C ratio is related to the risk of incident cardiovascular disease (CVD) risk is not well known. Therefore, we aimed to investigate the longitudinal effect of GGT/HDL-C ratio on incident CVD risk in three large cohorts of Korean men and women.

Methods

Data were assessed from 27,643 participants without CVD from the Korean Genome and Epidemiology Study (KoGES), Health Risk Assessment Study (HERAS), and Korea Health Insurance Review and Assessment (HIRA) (HERAS-HIRA) datasets. The participants were divided into four groups according to the GGT/HDL-C quartiles. We prospectively assessed hazard ratios (HRs) with 95% confidence intervals (CIs) for CVD using multivariate Cox proportional-hazard regression models over a 50-month period following the baseline survey.

Results

During the follow-up period, 949 patients (3.4%; 529 men and 420 women) developed CVD. The HRs of CVD for GGT/HDL-C quartiles 2-4 were 1.36 (95% CI, 0.91-2.02), 1.54 (95% CI, 1.05-2.26), and 1.66 (95% CI, 1.12-2.47) after adjusting for metabolic parameters in women, but GGT/HDL-C did not show a trend toward increases in incident CVD in men. Regional discrepancies were evident in the results; the increase in HR in the metropolitan hospital cohort was more pronounced than that in the urban cohort, and the risk was not increased in the rural cohort.

Conclusion

GGT/HDL-C ratio may be a useful predictive marker for CVD in women. Furthermore, the prevalence of CVD was strongly correlated with the GGT/HDL-C ratio in metropolitan areas, and this correlation was more significant than that observed with GGT or HDL-C in isolation.

Expanding potential targets of herbal chemicals by node2vec based on herb-drug interactions

BACKGROUND

The identification of chemical-target interaction is key to pharmaceutical research and development, but the unclear materials basis and complex mechanisms of traditional medicine (TM) make it difficult, especially for low-content chemicals which are hard to test in experiments. In this research, we aim to apply the node2vec algorithm in the context of drug-herb interactions for expanding potential targets and taking advantage of molecular docking and experiments for verification.

METHODS

Regarding the widely reported risks between cardiovascular drugs and herbs, Salvia miltiorrhiza (Danshen, DS) and Ligusticum chuanxiong (Chuanxiong, CX), which are widely used in the treatment of cardiovascular disease (CVD), and approved drugs for CVD form the new dataset as an example. Three data groups DS-drug, CX-drug, and DS-CX-drug were applied to serve as the context of drug-herb interactions for link prediction. Three types of datasets were set under three groups, containing information from chemical-target connection (CTC), chemical-chemical connection (CCC) and protein-protein interaction (PPI) in increasing steps. Five algorithms, including node2vec, were applied as comparisons. Molecular docking and pharmacological experiments were used for verification.

RESULTS

Node2vec represented the best performance with average AUROC and AP values of 0.91 on the datasets "CTC, CCC, PPI". Targets of 32 herbal chemicals were identified within 43 predicted edges of herbal chemicals and drug targets. Among them, 11 potential chemical-drug target interactions showed better binding affinity by molecular docking. Further pharmacological experiments indicated caffeic acid increased the thermal stability of the protein GGT1 and ligustilide and low-content chemical neocryptotanshinone induced mRNA change of FGF2 and MTNR1A, respectively.

CONCLUSIONS

The analytical framework and methods established in the study provide an important reference for researchers in discovering herb-drug interactions, alerting clinical risks, and understanding complex mechanisms of TM.

Valproate-Induced Metabolic Syndrome

Valproic acid (VPA) and its salts (sodium calcium magnesium and orotic) are psychotropic drugs that are widely used in neurology and psychiatry. The long-term use of VPA increases the risk of developing adverse drug reactions (ADRs), among which metabolic syndrome (MetS) plays a special role. MetS belongs to a cluster of metabolic conditions such as abdominal obesity, high blood pressure, high blood glucose, high serum triglycerides, and low serum high-density lipoprotein. Valproate-induced MetS (VPA-MetS) is a common ADR that needs an updated multidisciplinary approach to its prevention and diagnosis. In this review, we consider the results of studies of blood (serum and plasma) and the urinary biomarkers of VPA-MetS. These metabolic biomarkers may provide the key to the development of a new multidisciplinary personalized strategy for the prevention and diagnosis of VPA-MetS in patients with neurological diseases, psychiatric disorders, and addiction diseases.

Effects of curcumin/turmeric supplementation on liver function in adults: A GRADE-assessed systematic review and dose-response meta-analysis of randomized controlled trials

INTRODUCTION

Liver conditions are major burdens upon health systems around the world. Turmeric /curcumin is believed to possess therapeutic features in ameliorating various metabolic disorders. In this systematic review and meta-analysis of the randomized controlled trials (RCTs), we examined the effect of turmeric/curcumin supplementation on some liver function tests (LFTs).

METHODS

We comprehensively searched online databases (i.e. PubMed, Scopus, Web of Science, Cochrane Library, and Google Scholar) from inception up to October 2022. Final outcomes included aspartate aminotransferase (AST), alanine aminotransferase (ALT), and gamma-glutamyl transferase (GGT). Weighted mean differences (WMDs) were reported. In case of between-study heterogeneity, subgroup analysis was conducted. Non-linear dose-response analysis was carried out to detect the potential effect of dosage and duration. The registration code is CRD42022374871.

RESULTS

Thirty-one RCTs were included in the meta-analysis. Turmeric/curcumin supplementation significantly reduced blood levels of ALT (WMD = -4.09 U/L; 95 % CI = -6.49, -1.70) and AST (WMD = -3.81 U/L; 95 % CI = -5.71, -1.91), but not GGT (WMD: -12.78 U/L; 95 % CI: -28.20, 2.64). These improvements, though statistically significant, do not ensure clinical effectiveness.

CONCLUSION

It seems that turmeric/curcumin supplementation might be effective in improving AST and ALT levels. However, further clinical trials are needed to examine its effect on GGT. Quality of the evidence across the studies was low for AST and ALT and very low for GGT. Therefore, more studies with high quality are needed to assess this intervention on hepatic health.

Evaluation of Cottonseed Meal as an Alternative to Fish Meal in Diet for Juvenile Asian Red-Tailed Catfish Hemibagrus wyckioides

A 10-week trial was performed to investigate the effects of replacing fishmeal with cottonseed meal (CSM) on the growth rate, protein metabolism, and antioxidant response of Asian red-tailed catfish Hemibagrus wyckioides. Five isonitrogenous and isocaloric diets (C0, C8.5, C17.2, C25.7, and C34.4) were prepared to contain 0%, 8.5%, 17.2%, 25.7%, and 34.4% CSM replacing fishmeal, respectively. The weight gain, daily growth coefficient, pepsin, and intestinal amylase activities initially increased and then decreased with the raising dietary CSM levels; the highest values were observed in the C17.2 group (P < 0.05). However, feed cost exhibited the opposite trend. With the increasing dietary CSM levels, the protein efficiency ratio and intestinal trypsin activity decreased but feed conversion rate increased gradually; while no differences were observed among the C0, C8.5, and C17.2 groups (P > 0.05). Dietary CSM inclusion regardless of levels increased the plasma growth hormone level as well as hepatic aspartate aminotransferase (AST) and γ-glutamyl transpeptidase activities but decreased the plasma glutamate dehydrogenase and AST activities (P < 0.05). With the increasing dietary CSM levels, the plasma alkaline phosphatase (AKP) and hepatic superoxide dismutase activities decreased but malondialdehyde content increased gradually, while no differences were observed among the C0, C8.5, and C17.2 groups (P > 0.05). The plasma immunoglobulin M content and hepatic glutathione reductase activity initially increased but then decreased with the raising dietary CSM levels; the highest values were found in the C17.2 group. These results indicated that dietary CSM inclusion level up to 17.2% improved the growth rate, feed cost, digestive enzyme activity, and protein metabolism without compromising antioxidant capacity of H. wyckioide, whereas these parameters were depressed by further inclusion of CSM. CSM is a potentially cost-effective alternative plant protein source in diet of H. wyckioide.

Fontan-associated liver disease: Diagnosis, surveillance, and management

The Fontan operation is a lifesaving procedure for patients with functional single-ventricle congenital heart disease, where hypoplastic left heart syndrome is the most frequent anomaly. Hemodynamic changes following Fontan circulation creation are now increasingly recognized to cause multiorgan affection, where the development of a chronic liver disease, Fontan-associated liver disease (FALD), is one of the most important morbidities. Virtually, all patients with a Fontan circulation develop liver congestion, resulting in fibrosis and cirrhosis, and most patients experience childhood onset. FALD is a distinctive type of congestive hepatopathy, and its pathogenesis is thought to be a multifactorial process driven by increased nonpulsatile central venous pressure and decreased cardiac output, both of which are inherent in the Fontan circulation. In the advanced stage of liver injury, complications of portal hypertension often occur, and there is a risk of developing secondary liver cancer, reported at young age. However, FALD develops with few clinical symptoms, a surprisingly variable degree of severity in liver disease, and with little relation to poor cardiac function. The disease mechanisms and modifying factors of its development are still not fully understood. As one of the more important noncardiac complications of the Fontan circulation, FALD needs to be diagnosed in a timely manner with a structured monitoring scheme of disease development, early detection of malignancy, and determination of the optimal time point for transplantation. There is also a clear need for consensus on the best surveillance strategy for FALD. In this regard, imaging plays an important role together with clinical scoring systems, biochemical workups, and histology. Patients operated on with a Fontan circulation are generally followed up in cardiology units. Ultimately, the resulting multiorgan affection requires a multidisciplinary team of healthcare personnel to address the different organ complications. This article discusses the current concepts, diagnosis, and management of FALD, with special emphasis on the role of different imaging techniques in the diagnosis and monitoring of disease progression, as well as current recommendations for liver disease surveillance.

Association between γ-Glutamyl Transpeptidase and SARS-CoV-2 Spike Antibody Titers among BNT162b2 Vaccine Recipients

BACKGROUND

Increased γ-glutamyl transpeptidase (GGT) levels can deplete plasma glutathione, which in turn impairs immune regulation; however, evidence on GGT levels and post-vaccine immunogenicity is lacking.

OBJECTIVE

To examine the association between GGT and SARS-CoV-2 spike IgG antibodies.

METHODS

Participants were 1479 medical staff (aged 21 to 75 years) who received a SARS-CoV-2 antibody test after their second vaccine and whose GGT levels were measured before the vaccine rollout. Elevated and highly elevated GGT levels were defined as 51-80 and ≥81 U/L, respectively. Multivariable linear regression was used to calculate the means of SARS-CoV-2 spike IgG.

RESULTS

In a basic model, both elevated and highly elevated GGT levels were associated with significantly lower antibody titers. The ratio of mean (95% CI) was 0.83 (0.72-0.97) and 0.69 (0.57-0.84) for elevated and highly elevated GGT levels, respectively. However, these associations were largely attenuated after additional adjustment for potential confounders. An inverse association between GGT levels and antibody titers was found in women [0.70 (0.51-0.97)], normal-weight adults [0.71 (0.51-0.98)], and non-drinkers [0.73 (0.46-1.14)] but not in men, overweight adults, and alcohol drinkers.

CONCLUSIONS

Circulating GGT concentrations were associated with the humoral immune response after COVID-19 vaccination, but this relationship could be ascribed to confounders such as sex, BMI, and alcohol drinking rather than GGT per se.

Potential Association of Isolated γ-Glutamyltransferase Elevation with Incident Ischemic Heart Disease in Lean Koreans

Isolated elevation of γ-glutamyltransferase (GGT), a microsomal membrane-bound protein, is commonly observed in non-obese Koreans without diabetes, and its clinical implications are not well-known. Therefore, we aimed to investigate the longitudinal effect of isolated GGT on the incidence of ischemic heart disease (IHD) risk in a large cohort of lean non-diabetic Koreans. Data were obtained from the Health Risk Assessment Study (HERAS) and Korea Health Insurance Review and Assessment (HIRA) datasets. The participants were divided into four groups according to the GGT quartile after the exclusion of those participants with diabetes, a body mass index (BMI) ≥ 25 kg/m2, alanine aminotransferase (ALT) ≥ 40 IU/L, and aspartate aminotransferase (AST)/ALT > 1.5, as well as those positive for hepatitis B surface antigen or hepatitis C antibody. We prospectively assessed the hazard ratios (HRs) with 95% confidence intervals (CIs) for IHD using multivariate Cox proportional hazard regression models over a 50-month period. During the follow-up period, 183 individuals (1.85%) developed IHD. After setting the lowest GGT quartile as a reference group, the HRs of IHD for GGT quartiles 2−4 were 1.66 (95% CI 0.95−2.89), 1.82 (95% CI 1.05−3.16), and 1.98 (95% CI 1.12−3.50), respectively, after adjusting for age, sex, body mass index, smoking status, alcohol consumption, physical activity, mean arterial blood pressure, fasting plasma glucose, and dyslipidemia. An isolated high GGT may be an additional measure for assessing and managing future IHD risks among lean Koreans without diabetes.

Binding of Gamma-Glutamyl Transferase to TLR4 Signalling Allows Tissue Factor Activation in Monocytes

Gamma-glutamyl transferase (GGT) is involved in the progression of atherosclerosis, since its enzymatic activity promotes the generation of reactive oxygen species (ROS). Besides, GGT may act as a prothrombotic factor by inducing tissue factor (TF) expression, independently of its enzymatic activity. The aim of this study was to assess whether GGT-induced TF stimulation was a consequence of binding to toll-like receptor 4 (TLR4) expressed on monocytes, the precursors of macrophages and foam cells which colocalize with GGT activity within atherosclerotic plaques. Experiments were performed in human peripheral blood mononuclear cells (PBMCs), THP-1 cells (a monocytic cellular model), and HEK293 cells, which were genetically modified to study the activation of TLR4. TF procoagulant activity was assessed by a one-stage clotting time test, and TF protein expression was estimated by western blot. Human recombinant (hr) GGT protein increased TF procoagulant activity and protein expression in both PBMCs and THP-1 cells. The GGT-induced TF stimulation was prevented by cellular pretreatment with TLR4/NF-κB inhibitors (LPS-Rs, CLI-095, and BAY-11-7082), and HEK293 cells lacking TLR4 confirmed that TLR4 is essential for GGT-induced activation of NF-κB. In conclusion, hrGGT induced TF expression in monocytes through a cytokine-like mechanism that involved the activation of TLR4/NF-κB signaling.

Gamma glutamyl transferases in association with cardiovascular risk scores in non-diabetic hypertensive Cameroonians: preliminary data from HYRICCA study

Objective

The usefulness of gamma glutamyl transferase (GGT) as biomarker of cardiovascular risk (CVR) remains unexplored in sub-Saharan Africans. To evaluate their relevance on CVR assessment in non-diabetic hypertensive Cameroonians. This was a prospective cross-sectional study on non-diabetic hypertensive adults aged 57.7 ± 10 years (62% female), without evidence of acute or chronic liver disease, in which we assessed GGT levels and correlates it with validated CVR biomarkers, CVR scores (WHO risk score, Framingham 2008, ASCVD 2013, EuroSCORE 2003, and Reynolds score), and plasma atherogenic index (PAI).

Results

We found a positive but weak association between GGT and PAI on linear regression [0.004 (0.001; 0.007); p = 0.021], which was dependent of triglycerides levels (r = 0.17; p = 0.03). We did not find a significant association between GGT levels and the results of the CVR scores studied; Although being related to atherogenic risk, as reported in literature in non-sub-Saharan Africans, GGTs would be of little value for CVR assessment in our population.

Antifibrotic effect and long-term outcome of SGLT2 inhibitors in patients with NAFLD complicated by diabetes mellitus

The aim of this retrospective multicenter study was to clarify the antifibrotic effect and long-term outcome of sodium glucose cotransporter 2 inhibitors (SGLT2-Is) in patients with nonalcoholic fatty liver disease (NAFLD) complicated by type 2 diabetes mellitus (T2DM). Of the 1262 consecutive patients with T2DM who recently received SGLT2-Is, 202 patients with NAFLD had been receiving SGLT2-Is for more than 48 weeks and were subjected to this analysis. Furthermore, 109 patients who had been on SGLT2-I therapy for more than 3 years at the time of analysis were assessed for the long-term effects of SGLT2-Is. Significant decreases in body weight, liver transaminases, plasma glucose, hemoglobin A1c, and Fibrosis-4 (FIB-4) index were found at week 48. Overall, the median value of FIB-4 index decreased from 1.42 at baseline to 1.25 at week 48 (p < 0.001). In the low-risk group (FIB-4 index < 1.3), there was no significant change in the FIB-4 index. In the intermediate-risk (≥1.3 and <2.67) and high-risk (≥2.67) groups, the median levels significantly decreased from 1.77 and 3.33 at baseline to 1.58 and 2.75 at week 48, respectively (p < 0.001 for both). Improvements in body weight, glucose control, liver transaminases, and FIB-4 index were found at 3 years of SGLT2-I treatment. In the intermediate-risk and high-risk groups (≥1.3 FIB-4 index), the FIB-4 index maintained a significant reduction from baseline throughout the 3 years of treatment. Conclusion: This study showed that SGLT2-Is offered a favorable effect on improvement in FIB-4 index as a surrogate marker of liver fibrosis in patient with NAFLD complicated by T2DM, especially those with intermediate and high risks of advanced fibrosis, and this antifibrotic effect is sustained for the long term.

Blood and Urinary Biomarkers of Antipsychotic-Induced Metabolic Syndrome

Metabolic syndrome (MetS) is a clustering of at least three of the following five medical conditions: abdominal obesity, high blood pressure, high blood sugar, high serum triglycerides, and low serum high-density lipoprotein (HDL). Antipsychotic (AP)-induced MetS (AIMetS) is the most common adverse drug reaction (ADR) of psychiatric pharmacotherapy. Herein, we review the results of studies of blood (serum and plasma) and urinary biomarkers as predictors of AIMetS in patients with schizophrenia (Sch). We reviewed 1440 studies examining 38 blood and 19 urinary metabolic biomarkers, including urinary indicators involved in the development of AIMetS. Among the results, only positive associations were revealed. However, at present, it should be recognized that there is no consensus on the role of any particular urinary biomarker of AIMetS. Evaluation of urinary biomarkers of the development of MetS and AIMetS, as one of the most common concomitant pathological conditions in the treatment of patients with psychiatric disorders, may provide a key to the development of strategies for personalized prevention and treatment of the condition, which is considered a complication of AP therapy for Sch in clinical practice.

Elevated gamma‐glutamyl transferase levels are associated with stroke recurrence after acute ischemic stroke or transient ischemic attack

Aims

Methods

Results

Conclusion

Effect of Omega-3 Polyunsaturated Fatty Acids on Lipid Metabolism in Patients With Metabolic Syndrome and NAFLD

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease. n-3 polyunsaturated fatty acids (n-3-PUFAs) have been reported to ameliorate the progression of NAFLD in experimental studies; however, clinical trials have yielded contradictory results. The aim of our study was to assess the effects of n-3-PUFA administration on lipid metabolism and the progression of NAFLD in patients with metabolic syndrome. Sixty patients with metabolic syndrome and NAFLD were randomized in a double-blind placebo-controlled trial (3.6 g/day n-3-PUFA vs. placebo). During the 1-year follow-up, the patients underwent periodic clinical and laboratory examinations, liver stiffness measurements, magnetic resonance spectroscopy of the liver, and plasma lipidomic analyses. After 12 months of n-3-PUFA administration, a significant decrease in serum GGT activity was recorded compared with the placebo group (2.03 ± 2.8 vs. 1.43 ± 1.6; P < 0.05). Although no significant changes in anthropometric parameters were recorded, a significant correlation between the reduction of liver fat after 12 months of treatment-and weight reduction-was observed; furthermore, this effect was clearly potentiated by n-3-PUFA treatment (P < 0.005). In addition, n-3-PUFA treatment resulted in substantial changes in the plasma lipidome, with n-3-PUFA-enriched triacylglycerols and phospholipids being the most expressed lipid signatures. Conclusion: Twelve months of n-3-PUFA treatment of patients with NAFLD patients was associated with a significant decrease in GGT activity, the liver fat reduction in those who reduced their weight, and beneficial changes in the plasma lipid profile.

Obese Vegetarians and Omnivores Show Different Metabolic Changes: Analysis of 1340 Individuals

Our study evaluated the association between the increase in body mass index (BMI) in men and women (menstruating and non-menstruating) (n = 1340) with different dietary groups (omnivores, semi-vegetarians, lacto-ovo-vegetarian, and vegans) and the measurement of the biochemical markers high-sensitive C-reactive protein (hs-CRP), ferritin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), glycated hemoglobin (HbA1C), and insulin resistance index (HOMA-IR). Increasing BMI values in all groups and dietary profiles were related to a significant increase in hs-CRP (p < 0.0001), ALT (p = 0.02), ferritin (p = 0.009), and HbA1C (p < 0.0001), with no difference between dietary groups (p < 0.05). The increase in BMI increases the levels of HOMA-IR (p < 0.0001) and GGT (p < 0.05), with higher values found in men when compared to women (p < 0.0001 for HOMA- IR and p = 0.0048 for GGT). The association between ALT and BMI was different between dietary groups, as it showed a decrease in vegan women who do not menstruate compared to other dietary groups (p = 0.0099). When including only obese individuals (BMI ≥ 30 kg/m2, n = 153) in the analysis, we observed lower concentrations of GGT and ferritin in vegetarians than in omnivores, regardless of gender and menstrual blood loss (p = 0.0395). Our data showed that for both vegetarians and omnivores, the higher the BMI, the worse the metabolic parameters. However, regarding obesity, vegetarians showed better antioxidant status (lower GGT elevation) and lower inflammatory status (lower ferritin elevation), which may provide them with potential protection in the development of morbidities associated with overweight.

Gamma-glutamyl transferase levels are associated with the occurrence of post-stroke cognitive impairment: a multicenter cohort study

Background

Gamma-glutamyl transferase (GGT) is involved in maintenance of physiological concentrations of glutathione in cells, and protects them from oxidative stress-induced damage. However, its role in post-stroke cognitive impairment (PSCI) remains unknown. Here, we investigated the effects of serum GGT on PSCI.

Methods

We conducted a prospective, multicenter cohort study. A total of 1, 957 participants with a minor ischemic stroke or transient ischemic attack whose baseline GGT levels were measured were enrolled from the Impairment of Cognition and Sleep (ICONS) study of the China National Stroke Registry-3 (CNSR-3). They were categorized into four groups according to quartiles of baseline GGT levels. Cognitive functions were assessed using the Montreal Cognitive Assessment (MoCA) approach. Multiple logistic regression models were performed to evaluate the relationship between GGT and PSCI at 3 months follow-up.

Results

Among the 1957 participants, 671 (34.29%) patients suffered PSCI at 3 months follow-up. The highest GGT level quartile group exhibited a lower risk of PSCI in the fully adjusted model [OR (95% CI): 0.69 (0.50-0.96)], relative to the lowest group. Moreover, incorporation of GGT to the conventional model resulted in slight improvements in PSCI outcomes after 3 months (NRI: 12.00%; IDI: 0.30%).

Conclusions

Serum GGT levels are inversely associated with the risk of PSCI, with extremely low levels being viable risk factors for PSCI.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-022-02587-4.

A Path FORWARD: Development of a Comprehensive Multidisciplinary Clinic to Create Health and Wellness for the Child and Adolescent with a Fontan Circulation

Today, it is anticipated most individuals diagnosed with single-ventricle malformation will survive surgical reconstruction through a successful Fontan operation. As greater numbers of patients survive, so has the recognition that individuals with Fontan circulation face a variety of challenges. The goal of a normal quality and duration of life will not be reached by all. The hurdles fall into a variety of domains. From a cardiovascular perspective, the Fontan circulation is fundamentally flawed by its inherent nature of creating a state of chronically elevated venous pressure and congestion, accompanied by a relatively low cardiac output. Ventricular dysfunction, atrioventricular valve regurgitation, and arrhythmia may directly impact cardiac performance and can progress with time. Problems are not limited to the cardiovascular system. Fontan circulatory physiology impacts a multitude of biological processes and health parameters outside the heart. The lymphatic circulation is under strain manifesting as variable degrees of protein-rich lymph loss and immune system dysregulation. Organ system dysfunction develops through altered perfusion profiles. Liver fibrosis is ubiquitous, and a process of systemic fibrogenesis in response to circulatory stressors may affect other organs as well. Somatic growth and development can be delayed. Behavioral and mental health problems are common, presenting as clinically important levels of anxiety and depression. Most striking is the high variability in prevalence and magnitude of these complications within the population, indicating the likelihood of additional factors enhancing or mitigating their emergence. We propose that optimal care for the individual with single ventricle and a Fontan circulation is ideally offered in a comprehensive multidisciplinary manner, with attention to elements that are beyond cardiac management alone. In this report, we share the concepts, our experiences, and perspectives on development of a clinic model-the "Fontan rehabilitation, wellness and resilience development" or FORWARD program. We provide insights into the mechanics of our multidisciplinary model of care and the benefits offered serving our growing population of individuals with a Fontan circulation and their families.

Effect of Nutrition on Age-Related Metabolic Markers and the Gut Microbiota in Cats

Age-related changes in the gut microbiota and metabolites are associated with the increased risk of detrimental conditions also seen with age. This study evaluated whether a test food with potential anti-aging benefits results in favorable changes in plasma and fecal metabolites and the fecal microbiota in senior cats. Forty healthy domestic cats aged 8.3–13.5 years were fed a washout food for 30 days, then control or test food for 30 days. After another 30-day washout, cats were switched to the other study food for 30 days. Assessment of plasma and fecal metabolites showed lower levels of metabolites associated with detrimental processes (e.g., uremic toxins) and higher levels of metabolites associated with beneficial processes (e.g., tocopherols) after cats consumed the test food compared with the control food. A shift toward proteolysis with the control food is supported by higher levels of amino acid metabolites and lower levels of carbohydrate metabolites. Operational taxonomic units of greater abundance with the test food positively correlated with carbohydrate and nicotinic acid metabolites, and negatively correlated with uremic toxins, amino acid metabolism, secondary bile salts, and branched-chain fatty acids. Taken together, the test food appears to result in greater levels of metabolites and microbiota associated with a healthier state.

Blood biomarker levels by total sleep duration: cross-sectional analyses in UK Biobank

BACKGROUND

Short or long sleep duration has been associated with some major chronic diseases, but whether disease-related blood biomarkers vary according to habitual sleep duration is unclear. This cross-sectional study aimed to assess blood biomarker levels in relation to total sleep duration.

METHODS

The analysis includes 459,796 white British adults aged 40-69 during 2006-2010 in UK Biobank. At recruitment, blood samples and self-reported information on total sleep duration were collected from participants. A panel of blood biomarkers were measured. Using linear regression, we estimated geometric mean concentrations of blood biomarkers and mean ratio of ApoB/ApoA1 by sleep duration adjusted for sex, age at data collection, time of blood collection, and lifestyle covariates.

RESULTS

Percentage differences in the concentrations of most biomarkers by sleep duration were modest. The largest differences were for C-reactive protein (CRP, an inflammatory biomarker) and gamma glutamyltransferase (GGT, a liver function biomarker), and the differences were markedly attenuated after multivariable-adjustment. The multivariable-adjusted geometric means of CRP and of GGT were 14% and 14% higher in <6 h vs 7-8 h of sleep; and 22% and 12% higher in >9 h vs 7-8 h of sleep, respectively.

CONCLUSION

In white British adults, most blood biomarker levels varied only modestly with sleep duration and the remaining associations may be due to residual confounding.

Risk assessment in pulmonary hypertension based on routinely measured laboratory parameters

BACKGROUND

γ-glutamyl transferase (GGT), the aspartate aminotransferase/alanine aminotransferase (AST/ALT) ratio, and the neutrophil-to-lymphocyte ratio (NLR) are prognostic biomarkers in several cardiovascular diseases, but their relevance in pulmonary hypertension (PH) is not fully understood. We aimed to assess their prognostic value in patients with pulmonary arterial hypertension (PAH) and chronic thromboembolic PH (CTEPH).

METHODS

We retrospectively analyzed 731 incident patients with idiopathic PAH or CTEPH who entered the Giessen PH registry during 1993-2019. A risk stratification score based on GGT, AST/ALT ratio, and NLR tertiles was compared with a truncated version of the European Society of Cardiology/European Respiratory Society (ESC/ERS) risk stratification scheme. Associations with survival were evaluated using Kaplan-Meier and Cox regression analyses. External validation was performed in 311 patients with various types of PAH or CTEPH from a second German center.

RESULTS

GGT levels, AST/ALT, and NLR independently predicted mortality at baseline and during follow-up. The scoring system based on these biomarkers predicted mortality at baseline and during follow-up (both log-rank p < 0.001; hazard ratio [95% confidence interval], high vs low risk: baseline, 7.6 [3.9, 15.0]; follow-up, 13.3 [4.8, 37.1]). Five-year survival of low, intermediate, and high risk groups was 92%, 76%, and 51%, respectively, at baseline and 95%, 78%, and 50%, respectively, during follow-up. Our scoring system showed characteristics comparable to the ESC/ERS scheme, and predicted mortality in the validation cohort.

CONCLUSION

GGT, AST/ALT, and NLR were reliable prognostic biomarkers at baseline and during follow-up, with predictive power comparable to the gold standard for risk stratification.

Analysis of Risk Factors for Changes in the Renal Two-Dimensional Image in Gout Patients

OBJECTIVE

To explore the effects of different blood uric acid levels in gout patients on the two-dimensional image of the kidney and the risk factors for gout-related kidney damage for providing clinical evidence to enable early prevention and treatment of gout-related kidney damage.

METHODS

We obtained information of 227 patients with primary gout and estimated the association between two-dimensional kidney images and clinical indicators using binary logistic regression.

RESULTS

Our study showed that different uric acid levels, age, disease course, cystatin C (CysC) level, and γ-glutamyl transpeptidase level were correlated with echo of the renal medulla (P < 0.05). CysC level was correlated with the renal cortex thickness and kidney stones in different uric acid-level groups (P < 0.05). Disease course, aspartate transaminase (AST) level, creatinine (CREA) level, and tophi were risk factors for renal cortex thinning in gout patients (P = 0.045, 0.026, 0.004, 0.006, respectively). The disease course, platelet (PLT) count, and high-density lipoprotein (HDL-C) level were risk factors for kidney stone formation in gout patients (P = 0.037, 0.022, 0.023, respectively), while CysC level and C-reactive protein (CRP) level were risk factors for increased renal medulla echo in these patients (P = 0.022, 0.028, respectively).

CONCLUSION

Our study revealed disease course, AST level, CREA level, tophi, PLT count, HDL-C level, CysC level and CRP level may be important predictors of renal image changes.

A clinical model to predict fibrosis on liver biopsy in paediatric subjects with nonalcoholic fatty liver disease

The incidence of nonalcoholic fatty liver disease (NAFLD) in children is rapidly increasing. Liver fibrosis is a poor prognostic feature that independently predicts cirrhosis. The time that intercedes the first medical encounter and biopsy is rate-limiting to multi-modal treatment. This study aimed to identify non-invasive parameters to predict advanced NAFLD and fibrosis. We conducted a single-center, retrospective 10-year analysis of 640 paediatric patients who underwent liver biopsy. 55 patients, age 3-21 years, had biopsy-confirmed NAFLD. We assessed primary outcomes, NAFLD activity score (NAS) and fibrosis scores, against non-invasive parameters by linear regression, by using binary cutoff values, and by a multivariate logistic regression fibrosis prediction model. NAS correlated with platelets and female sex. Fibrosis scores correlated with platelet counts, gamma glutamyl transferase (GGT), and ultrasound shear wave velocity. 25-hydroxy-vitamin D and GGT differentiated mild versus moderate-to-advanced fibrosis. Our multivariate logistical regression model-based scoring system predicted F2 or higher (parameters: BMI%, vitamin D, platelets, GGT), with sensitivity and specificity of 0.83 and 0.95 (area under the ROC curve, 0.944). We identify a clinical model to identify high-risk patients for expedited biopsy. Stratifying patients to abbreviate time-to-biopsy can attenuate delays in aggressive therapy for high-risk patients.

Association of Low Molecular Weight Plasma Aminothiols with the Severity of Coronavirus Disease 2019

Objective

Aminothiols (glutathione (GSH), cysteinylglycine (CG)) may play an important role in the pathogenesis of coronavirus disease 2019 (COVID-19), but the possible association of these indicators with the severity of COVID-19 has not yet been investigated.

Methods

The total content (t) and reduced forms (r) of aminothiols were determined in patients with COVID-19 (n = 59) on admission. Lung injury was characterized by computed tomography (CT) findings in accordance with the CT0-4 classification.

Results

Low tGSH level was associated with the risk of severe COVID-19 (tGSH ≤ 1.5 μM, mild vs. moderate/severe: risk ratio (RR) = 3.09, p = 0.007) and degree of lung damage (tGSH ≤ 1.8 μM, CT < 2 vs. CT ≥ 2: RR = 2.14, p = 0.0094). The rGSH level showed a negative association with D-dimer levels (ρ = -0.599, p = 0.014). Low rCG level was also associated with the risk of lung damage (rCG ≤ 1.3 μM, CT < 2 vs. CT ≥ 2: RR = 2.28, p = 0.001). Levels of rCG (ρ = -0.339, p = 0.012) and especially tCG (ρ = -0.551, p = 0.004) were negatively associated with platelet count. In addition, a significant relationship was found between the advanced oxidation protein product level and tGSH in patients with moderate or severe but not in patients with mild COVID-19.

Conclusion

Thus, tGSH and rCG can be seen as potential markers for the risk of severe COVID-19. GSH appears to be an important factor to oxidative damage prevention as infection progresses. This suggests the potential clinical efficacy of correcting glutathione metabolism as an adjunct therapy for COVID-19.

Testosterone treatment improves liver function and reduces cardiovascular risk: A long-term prospective study

Objectives: To report the association between testosterone treatment in hypogonadal men with hepatic steatosis, non-alcoholic fatty liver disease and cardiovascular disease (CVD). Methods: A prospective study was conducted to assess the physiological and functional performance of the long-term effects of testosterone undecanoate treatment on hepatic steatosis in 496 hypogonadal men. Two groups were studied, the treatment group (T-group) of 312 patients treated with TU 1000 mg every 12 weeks and followed for 8 years, and an untreated control group (C-group) of 184 patients. We evaluated liver functions and Fatty Liver Index (FLI) according to Mayo Clinic parameters and guidelines. Results: The T-group showed a decrease in the FLI (from a mean [SD] of 83.70 [12.15] to 67.12 [19.21]), bilirubin (from a mean [SD] of 1.69 [4.21] to 1.31 [1.91] mg/dL), triglycerides (from a mean [SD] of 254.87 [92.99] to 213.37 [66.91] mg/dL), and gamma-glutamyl-transferase (from a mean [SD] of 39.45 [11.51] to 29.11 [7.68] U/L) over the duration of the study. Other parameters were also reduced in the T-group such as body mass index (from a mean [SD] of 31.59 [4.51] to 29.50 [3.84] kg/m²) and waist circumference (from a mean [SD] of 107.51 [9.95] to 101.86 [9.28] cm). A total of 25 deaths (7.8%) were recorded in the T-group, among them, 11 (44%) were related to CVD. While in the C-group 28 deaths (15.2%) were recorded and all the reported deaths (100%) were related to CVD. Conclusions: The findings suggest that long-term testosterone therapy in hypogonadal men improves liver function. While, the physiological and functional improvements in the liver may be associated with a decrease in CVD-related mortality.

Abbreviations

ALT: alanine transaminase; AR: androgen receptor; AST: aspartate transaminase; BMI: body mass index; CVD: cardiovascular disease; FLI: Fatty Liver Index; γ-GT: gamma-glutamyl-transferase; MetS: metabolic syndrome; LDL: low-density lipoprotein; NAFLD: non-alcoholic fatty liver disease; RCT: randomised controlled trial; T2DM: type II diabetes mellitus; TT: total testosterone; TTh: testosterone therapy; TU: testosterone undecanoate; WC: waist circumference

Gamma-Glutamyl Transpeptidase to Platelet Ratio: A New Inflammatory Marker Associated with Outcomes after Cardiac Arrest

Introduction

In recent years, gamma-glutamyl transpeptidase to platelet ratio (GPR) has been proposed as a new inflammatory marker. We aimed to evaluate the association between GPR and outcomes after cardiac arrest (CA).

Methods

A total of 354 consecutive patients with CA were included in this retrospective study. Patients were divided into three groups according to tertiles of GPR (low, n = 119; middle, n = 117; and high, n = 118). To determine the relationship between GPR and prognosis, a logistic regression analysis was performed. The ability of GPR to predict the outcomes was evaluated by receiver operating characteristic (ROC) curve analysis. Two prediction models were established, and the likelihood ratio test (LRT) and the Akaike Information Criterion (AIC) were utilized for model comparison.

Results

Among the 354 patients (age 62 [52, 74], 254/354 male) who were finally included in the analysis, those in the high GPR group had poor outcomes. Multivariate logistic regression analysis revealed that GPR was independently associated with the three outcomes, for ICU mortality (odds ratios (OR) = 1.738, 95% confidence interval (CI): 1.221-2.474, P = 0.002), hospital mortality (OR = 1.676[1.164 − 2.413], P = 0.005), and unfavorable neurologic outcomes (OR = 1.623[1.121 − 2.351], P = 0.010). The area under the ROC curve was 0.611 (95% Cl: 0.558-0.662) for ICU mortality, 0.600 (95% CI: 0.547-0.651) for hospital mortality, and 0.602 (95% CI: 0.549-0.653) for unfavorable neurologic outcomes. Further, the LRT analysis showed that compared with the model without GPR, the GPR-combined model had a higher likelihood ratio χ² score and smaller AIC.

Conclusion

GPR, as an inflammatory indicator, was independently associated with outcomes after CA. GPR is helpful in estimating the clinical outcomes of patients with CA.

Application of a Novel Prediction Model for Predicting 2-Year Risk of Non-Alcoholic Fatty Liver Disease in the Non-Obese Population with Normal Blood Lipid Levels: A Large Prospective Cohort Study from China

Purpose

The purpose of this study was to develop and validate a nomogram to better assess the 2-year risk of non-alcoholic fatty liver disease (NAFLD) in non-obese population with normal blood lipid levels.

Patients and Methods

This study was a secondary analysis of a prospective study. We included 3659 non-obese adults with normal blood lipid levels without NAFLD at baseline. A total of 2744 participants were included in the development cohort and 915 participants were included in the validation cohort. The least absolute contraction selection operator (LASSO) regression model was used to identify the best risk factors. Multivariate Cox regression analysis was used to construct the prediction model. The performance of the prediction model was assessed using Harrell’s consistency index (C-index), area under the receiver operating characteristic (AUROC) curve and calibration curve. Decision curve analysis was applied to evaluate the clinical usefulness of the prediction model.

Results

After LASSO regression analysis and multivariate Cox regression analysis on the development cohort, BMI, TG, DBIL, ALT and GGT were found to be risk predictors and were integrated into the nomogram. The C-index of development cohort and validation cohort was 0.819 (95% CI, 0.798 to 0.840) and 0.815 (95% CI, 0.781 to 0.849), respectively. The AUROC of 2-year NAFLD risk in the development cohort and validation cohort was 0.831 (95% CI, 0.811 to 0.851) and 0.797 (95% CI, 0.765 to 0.829), respectively. From calibration curves, the nomogram showed a good agreement between predicted and actual probabilities. The decision curve analysis indicated that application of the nomogram is more effective than the intervention-for-all-patients scheme.

Conclusion

We developed and validated a nomogram for predicting 2-year risk of NAFLD in the non-obese population with normal blood lipid levels.

Peri-operative derangement in liver function tests in older patients with neck of femur fracture

Neck of femur fracture is a common consequence of falls in the elderly with a large burden of morbidity and mortality. Derangement in liver function tests (LFTs) is frequently seen in elderly people with neck of femur (NOF) fracture in the peri-operative period and can indicate serious and treatable underlying pathology as well as prognosis.On admission, raised alkaline phosphatase (ALP) levels with normal gamma-glutamyl transferase (GGT) suggest underlying bone pathology such as osteomalacia or Paget's disease but do not confirm or exclude osteoporosis. ALP can also be raised by non-bone pathology such as congestive cardiac failure and chronic kidney disease. LFT derangement in cardiac failure is associated with poorer prognosis. Post-operatively, ALP levels rise after the first week with a peak at 3-4 weeks and then fall thereafter. The rate at which they fall may help indicate bone healing in trochanteric fractures. Derangement in other LFTs is commonly due to hepatic injury; causes include trauma, alcohol, and viral hepatitis. There are also iatrogenic causes including surgery and commonly prescribed medication such as beta-lactam antibiotics, non-steroidal anti-inflammatories, and paracetamol.The differential diagnosis for deranged LFTs in the elderly peri-operatively is wide; however, most causes can be elicited through careful history and examination with occasional need for further investigations.

Gamma-glutamyl transpeptidase elevation is associated with metabolic syndrome, hepatic steatosis, and fibrosis in patients with nonalcoholic fatty liver disease: A community-based cross-sectional study

This study aimed to analyze the association between elevated gamma-glutamyl transpeptidase (GGT) and metabolic syndrome (MetS), hepatic steatosis, and fibrosis in patients with nonalcoholic fatty liver disease (NAFLD). From August 2013 to August 2018, a community-based study was conducted in the northeastern part of Taiwan. Patients who underwent abdominal ultrasonography (US) and had no history of alcoholic liver disease were included. According to a US examination showing fatty liver degree, 1566 patients with NAFLD were divided into four groups: normal GGT, isolated GGT elevation, isolated alanine aminotransferase (ALT) elevation, and both GGT and ALT elevation groups. Further 1147 participants with normal serum ALT, GGT, and the abdominal US were included as the control group. GGT levels were associated with high sensitivity C-reactive protein, lower adiponectin, diabetes mellitus, and chronic kidney disease. A stepwise increase in odds ratio (OR) for MetS was found in the normal GGT group (OR = 1.71), isolated GGT elevation group (OR = 3.06), isolated ALT elevation (OR = 4.00), and both GGT + ALT elevation group (OR = 4.17) than the control group. Linear regression analysis revealed a positive association between GGT/ALT value and hepatic steatosis degree, GGT value, and degree of hepatic fibrosis. Hence, GGT elevation is associated with MetS, hepatic steatosis, and fibrosis in patients with NAFLD.

Association Between Sex-Specific Serum Gamma-Glutamyltransferase and Incidence of Hypertension in a Chinese Population Without Metabolic Syndrome: A Prospective Observational Study

Background: Higher serum gamma-glutamyltransferase (GGT) is associated with high risk of hypertension. We aimed to examine the association between sex-specific serum GGT levels and incident of hypertension in a Chinese population without metabolic syndrome. Methods: Participants who were free of hypertension and metabolic syndrome from the First Affiliated Hospital of Wenzhou Medical University between 2009 and 2014 were included. Participants were grouped into sex-specific quartiles of GGT levels (Q1-Q4) defined as: ≤19, 20-26, 27-38, and ≥39 U/L for male; ≤12, 13-15, 16-19, and ≥20 U/L for female. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for incidence of hypertension according to sex-specific quartiles of GGT levels. Kaplan-Meier analysis and interaction analysis were conducted. Results: Among 38,806 participants included (average age 36.0 years, 54.0% men), 4,505 of them developed hypertension. In the overall study population, using Q1 as the reference group, participants in Q2, Q3, and Q4 showed a higher risk of developing hypertension, with HRs (95% CIs) of 1.126 (1.029-1.232), 1.187 (1.083-1.302), and 1.300 (1.182-1.431), respectively (P < 0.001), after adjusting for known confounders. Sex-specific analysis showed that the adjusted HRs for participants in Q4 (reference: Q1) were greater in females [1.321 (1.100-1.586, P < 0.001)] than in males [1.268 (1.133-1.420, P < 0.001)] (P for interaction = 0.047). Moreover, interaction analysis showed that this association was consistently observed when the participants were stratified by age, body mass index, and fatty liver status. Conclusion: Among Chinese adults without metabolic syndrome, serum GGT level was positively associated with incidence of hypertension, and the association was stronger in females than in males.

Effects of Smoking, and Drinking on Serum Gamma-Glutamyl Transferase Levels Using Physical Examination Data: A Cross-Sectional Study in Northwest China

Purpose

Although drinking and smoking have been associated with gamma-glutamyl transferase (GGT) levels, studies on the effects of smoking and drinking on GGT levels are scarce. The objective of this study was to assess the individual and combined effects of smoking, drinking on GGT levels in the Shaanxi province of Northwest China.

Participants and Methods

A questionnaire survey was conducted in a population that underwent health examination at the First Affiliated Hospital of Xi’an Jiaotong University and included employees of enterprises or public institutions. The survey was used to collect the baseline characteristics, smoking status, and drinking status of the participants. This information was collected from January 2019 to December 2019. Data related to the physical examinations were exported using the hospital information system (HIS). A linear regression model was employed to explore the effects of smoking and drinking on GGT levels. The restricted cubic spline model was applied to assess the dose–response relationship between amount of smoking, alcohol consumption and GGT levels.

Results

A total of 10,177 participants were included in the study. Linear regression indicated that smoking (β=3.37, 95% CI: 2.57–4.17) and drinking (β=5.55 L, 95% CI: 4.40–6.71) individually, and collectively (β=9.30, 95% CI: 7.83–10.76) had a positive effect on GGT levels. The restricted cubic spline presented a linear dose–response relationship between the amount of daily smoking and GGT levels (P for non-linearity=0.148, P for overall association <0.001, OR=2.49, 95% CI: 1.27–4.90), and that between weekly alcohol consumption and GGT levels (P for non-linearity=0.231, P for overall association <0.001, OR=4.79, 95% CI: 1.72–13.32). In case of females, stratified analysis showed that in comparison to the reference group, only current drinkers had a significant effect on GGT levels (OR=3.37, 95% CI: 0.19–6.55).

Conclusion

Smoking and drinking have a dose-dependent and a synergistic effect on GGT levels. They should be controlled concurrently, especially among males.

Multi-omic analysis of stroke recurrence in African Americans from the Vitamin Intervention for Stroke Prevention (VISP) clinical trial

African Americans endure a nearly two-fold greater risk of suffering a stroke and are 2–3 times more likely to die from stroke compared to those of European ancestry. African Americans also have a greater risk of recurrent stroke and vascular events, which are deadlier and more disabling than incident stroke. Stroke is a multifactorial disease with both heritable and environmental risk factors. We conducted an integrative, multi-omic study on 922 plasma metabolites, 473,864 DNA methylation loci, and 556 variants from 50 African American participants of the Vitamin Intervention for Stroke Prevention clinical trial to help elucidate biomarkers contributing to recurrent stroke rates in this high risk population. Sixteen metabolites, including cotinine, N-delta-acetylornithine, and sphingomyelin (d17:1/24:1) were identified in t-tests of recurrent stroke outcome or baseline smoking status. Serum tricosanoyl sphingomyelin (d18:1/23:0) levels were significantly associated with recurrent stroke after adjusting for covariates in Cox Proportional Hazards models. Weighted Gene Co-expression Network Analysis identified moderate correlations between sphingolipid markers and clinical traits including days to recurrent stroke. Integrative analyses between genetic variants in sphingolipid pathway genes identified 29 nominal associations with metabolite levels in a one-way analysis of variance, while epigenomic analyses identified xenobiotics, predominately smoking-associated metabolites and pharmaceutical drugs, associated with methylation profiles. Taken together, our results suggest that metabolites, specifically those associated with sphingolipid metabolism, are potential plasma biomarkers for stroke recurrence in African Americans. Furthermore, genetic variation and DNA methylation may play a role in the regulation of these metabolites.

Alanine Aminotransferase and Gamma-Glutamyl Transpeptidase Predict Histologic Improvement in Pediatric Nonalcoholic Steatohepatitis

BACKGROUND AND AIMS

Predictive, noninvasive tools are needed to monitor key features of nonalcoholic fatty liver disease (NAFLD) in children that relate to improvement in liver histology. The purpose of this study was to evaluate the relationship between liver chemistries and liver histology using data from the CyNCh (Cysteamine Bitartrate Delayed-Release for the Treatment of NAFLD in Children) clinical trial.

APPROACH AND RESULTS

This study included 146 children. Improvement in liver histology, defined as decrease in nonalcoholic fatty liver disease (NAFLD) Activity Score ≥2 points without worsening of fibrosis, occurred in 43 participants (30%). There were 46 participants with borderline zone 1 nonalcoholic steatohepatitis (NASH) at baseline, with resolution in 28% (12 of 46). Multivariate models were constructed using baseline and change in alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyl transferase (GGT) at 52 weeks, for improvement in (1) liver histology primary outcome, (2) borderline zone 1 NASH, and (3) fibrosis. For improvement in histology, the model (P < 0.0001) retained baseline and change in GGT (area under the receiver operating characteristic [AUROC], 0.79; 95% confidence interval [CI], 0.71-0.87). For borderline zone 1 NASH, the model (P = 0.0004) retained baseline and change in ALT (AUROC, 0.80; 95% CI, 0.67-0.93). For fibrosis, the model (P < 0.001) retained baseline and change in ALT (AUROC, 0.80; 95% CI, 0.67-0.93). Additional clinical parameters were added to the models using Akaike's information criterion selection, and significantly boosted performance: improvement in histology with AUROC of 0.89 (95% CI, 0.82-0.95), borderline zone 1 NASH with AUROC of 0.91 (95% CI, 0.83-0.99), and fibrosis with AUROC of 0.89 (95% CI, 0.82-0.94). Models were validated using data from the TONIC (Treatment of Nonalcoholic Fatty Liver Disease in Children) trial.

CONCLUSIONS

In children with NAFLD, dynamic changes in serum ALT and GGT are associated with change in liver histology and appear to be powerful indicators of histological response.

Association between routine biomarkers and atrial fibrillation in patients undergoing implantation of a dual-chamber pacemaker

BACKGROUND

Elderly patients having a permanent pacemaker frequently have atrial remodeling. We examined the association between routine biomarkers and atrial fibrillation (AF) in patients receiving a dual-chamber pacemaker for sinus node disease (SND) or second-/third-degree atrioventricular block.

METHODS

We recorded clinical, laboratory, and electrocardiographic parameters as well as pacemaker lead parameters at implantation. The final analysis included 217 patients with SND and 393 patients with atrioventricular block. Notably, 102/217 (47%) of the SND patients (median age: 77 years, 54% men) and 54/393 (14%) of the atrioventricular block patients (median age: 79 years, 54% men) had AF history (paroxysmal or persistent).

RESULTS

Multivariable analysis showed that red blood cell distribution width (RDW) (OR: 1.17; 95% CI: 1.05-1.36; P = .05) and serum γ-glutamyl transferase (γGT) levels (OR: 1.15; 95% CI: 1.03-1.28; P = .04) were independently associated with AF history in patients with SND. In ROC curve analysis, the area under the curve (AUC) was 0.648; P < .01 for RDW, and 0.753; P < .01 for γGT. A RDW cut-off point of 14 was associated with AF with a sensitivity of 67% and a specificity of 68%, while a γGT cut-off point of 21 was associated with AF with a sensitivity of 80% and a specificity of 65%. In patients with second-/third-degree atrioventricular block, there were no significant independent correlations between AF and the parameters studied.

CONCLUSIONS

In elderly patients with SND, RDW and γGT have an independent association with AF history. Our study failed to show any corresponding associations in patients with advanced disorders of atrioventricular conduction.

Serum Gamma-Glutamyltransferase Levels Predict the Development of Cerebral Infarction in the Korean Population

PURPOSE

This study examined the relationship between serum gamma-glutamyltransferase concentration and the risk of cerebral infarction in the Koreans.

MATERIALS AND METHODS

A total of 209,481 out of 223,551 participants in the National Health Information Database who received medical checkups in 2009 were included in the final analysis. The diagnosis code ICD I63 was used for identifying cerebral infarction cases and tracked the development of cerebral infarction by 2013. Cox proportional hazards model was used to calculate hazard ratios (HRs) for cerebral infarction and their confidence interval (CI).

RESULTS

During a follow-up period of 915,387.5 person-years, 2403 incident cases of cerebral infarction developed between 2009 and 2013. After adjusting for multiple covariates, the hazard ratios (95% confidence interval) for incident cerebral infarction, comparing the second, third, and fourth quartile of serum gamma-glutamyltransferase levels with the first quartile, were 1.11 (0.98-1.27), 1.39 (1.22-1.58), and 1.49 (1.29-1.71), respectively (P for trend <0.001).

CONCLUSION

Elevated serum gamma-glutamyltransferase levels were independently associated with the future development of cerebral infarction in Koreans.

NAFLD, and cardiovascular and cardiac diseases: Factors influencing risk, prediction and treatment

BACKGROUND AND AIM

Non-alcoholic fatty liver disease (NAFLD), affecting up to around 30% of the world's adult population, causes considerable liver-related and extrahepatic morbidity and mortality. Strong evidence indicates that NAFLD (especially its more severe forms) is associated with a greater risk of all-cause mortality, and the predominant cause of mortality in this patient population is cardiovascular disease (CVD). This narrative review aims to discuss the strong association between NAFLD and increased risk of cardiovascular, cardiac and arrhythmic complications. Also discussed are the putative mechanisms linking NAFLD to CVD and other cardiac/arrhythmic complications, with a brief summary of CVD risk prediction/stratification and management of the increased CVD risk observed in patients with NAFLD.

RESULTS

NAFLD is associated with an increased risk of CVD events and other cardiac complications (left ventricular hypertrophy, valvular calcification, certain arrhythmias) independently of traditional CVD risk factors. The magnitude of risk of CVD and other cardiac/arrhythmic complications parallels the severity of NAFLD (especially liver fibrosis severity). There are most likely multiple underlying mechanisms through which NAFLD may increase risk of CVD and cardiac/arrhythmic complications. Indeed, NAFLD exacerbates hepatic and systemic insulin resistance, promotes atherogenic dyslipidaemia, induces hypertension, and triggers synthesis of proatherogenic, procoagulant and proinflammatory mediators that may contribute to the development of CVD and other cardiac/arrhythmic complications.

CONCLUSION

Careful assessment of CVD risk is mandatory in patients with NAFLD for primary prevention of CVD, together with pharmacological treatment for coexisting CVD risk factors.

Long-term testosterone therapy improves liver parameters and steatosis in hypogonadal men: a prospective controlled registry study

Non-alcoholic fatty liver disease (NAFLD) is associated with cardiovascular disease (CVD) and both are prevalent in men with testosterone deficiency. Long-term effects of testosterone therapy (TTh) on NAFLD are not well studied. This observational, prospective, cumulative registry study assesses long-term effects of testosterone undecanoate (TU) on hepatic physiology and function in 505 hypogonadal men (T levels ≤350 ng/dL). Three hundred and twenty one men received TU 1000 mg/12 weeks for up to 12 years following an initial 6-week interval (T-group), while 184 who opted against TTh served as controls (C-group). T-group patients exhibited decreased fatty liver index (FLI, calculated according to Mayo Clinic guidelines) (83.6 ± 12.08 to 66.91 ± 19.38), γ-GT (39.31 ± 11.62 to 28.95 ± 7.57 U/L), bilirubin (1.64 ± 4.13 to 1.21 ± 1.89 mg/dL) and triglycerides (252.35 ± 90.99 to 213 ± 65.91 mg/dL) over 12 years. Waist circumference and body mass index were also reduced in the T-group (107.17 ± 9.64 to 100.34 ± 9.03 cm and 31.51 ± 4.32 to 29.03 ± 3.77 kg/m²). There were 25 deaths (7.8%) in the T-group of which 11 (44%) were cardiovascular related. In contrast, 28 patients (15.2%) died in C-group, and all deaths (100%) were attributed to CVD. These data suggest that long-term TTh improves hepatic steatosis and liver function in hypogonadal men. Improvements in liver function may have contributed to reduced CVD-related mortality.

Left ventricular mass and urinary metabolomics in young black and white adults: The African-PREDICT study

BACKGROUND AND AIMS

Increased left ventricular mass is an independent predictor for cardiovascular events, and shown to be higher in black than white populations. To gain a better understanding of early factors contributing to increased left ventricular mass in young black adults, we investigated metabolomic profiles, identified and compared metabolites that associated with left ventricular mass index in healthy black and white adults.

METHODS AND RESULTS

We included normotensive black and white participants from the African-PREDICT study, with data on urinary metabolomics and echocardiography. Urinary metabolites were measured using three different analytical platforms. Univariate statistical analyses, including independent t-test (adjusted for multiple comparisons), effect size (d ≥ 0.3) and single regression analyses were used to identify metabolites. When comparing the black and white groups, the black group had higher central systolic blood pressure (p > 0.005), whereas left ventricular mass index was similar between the groups (p = 0.97). Three from a total of 192 metabolites were identified to be more abundant (p < 0.046) and inversely associated with left ventricular mass index in the black group only: hydroxyproline (β = -0.22; p = 0.045), glycine (β = -0.20; p = 0.049) and trimethylamine (β = -0.21; p = 0.037).

CONCLUSION

Higher urinary levels of hydroxyproline, glycine and trimethylamine were inversely associated with left ventricular mass index in the black adults only. Hydroxyproline and glycine are important in maintaining healthy collagen turnover and stability in the heart. Our results may reflect an increase in collagen biosynthesis and collagen deposition in the left ventricle due to higher central systolic blood pressure in the black population.

Very Low-Carbohydrate Ketogenic Diet for the Treatment of Severe Obesity and Associated Non-Alcoholic Fatty Liver Disease: The Role of Sex Differences

Very low-carbohydrate ketogenic diets (VLCKDs) are an emerging nutritional treatment for severe obesity and are associated with a significant improvement in non-alcoholic fatty liver disease (NAFLD). Little is known about the effect of sex differences on weight loss induced by following a VLCKD. The aim of this study was to investigate the effects of sex differences on weight loss and NAFLD improvement in patients with severe obesity undergoing a VLCKD. Forty-two females and 28 males with severe obesity underwent a 25-day VLCKD. Anthropometric parameters, bioimpedentiometry, degree of liver steatosis measured by ultrasonography, liver function tests, and glucose homeostasis were measured before and after the VLCKD. Males experienced a significantly larger excess body weight loss (EBWL) and a greater reduction in γ-glutamyl transferase (γGT) than females. Dividing the female group by menopausal status, a significant difference between males and pre-menopausal females was found for both EBWL and γGT. No significant difference between groups was observed for improvement in the Edmonton stage or in the degree of steatosis. We conclude that the efficacy of following a VLCKD in severe obesity is affected by sex differences and, for females, by menopausal status. Males seem to experience larger benefits than females in terms of EBWL and NAFLD improvement. These differences are attenuated after menopause, probably because of changes in hormonal profile and body composition.

Cell-Membrane-Localizing, Two-Photon Probe for Ratiometric Imaging of γ-Glutamyl Transpeptidase in Cancerous Cells and Tissues

γ-Glutamyl transpeptidase (GGT), a cell surface-bound protease, is associated with various diseases including cancer. The detection of the enzyme activity is an important subject, leading to about 40 activatable fluorescent probes so far. All of them, however, lack the membrane-localizing ability, raising a reliability issue in the quantitative analysis. Disclosed is the first fluorescent probe that senses the cell surface-bound enzyme, which, furthermore, is capable of ratiometric as well as two-photon imaging with desirable features. Ratiometric imaging of cancer cell lines reveals a 6.4-8.4-fold higher GGT levels than those in normal cell lines. A comparison of the enzyme activity in organ tissues of normal and tumor xenograft mice reveals notably different levels of enzyme activity depending on the kind of tissue. Normal tissues exhibited comparable levels of enzyme activity, except the kidney that has significantly higher GGT activity (2.7-4.0-fold) than the other organs. Compared with the normal tissues, considerably higher enzyme activity was observed in the tumor tissues of the thigh (4.0-fold), colon (2.5-fold), lung (3.6-fold), and liver (2.1-fold), but essentially no enhanced activity in the tumor tissues of the spleen, stomach, and pancreas and a comparable level in both the tumor and normal kidney tissues were observed. The probe offers practical means for studying GGT-associated biology in cells and tissues by one- as well as two-photon ratiometric imaging.