Utility of alpha-glutathione S-transferase assessment in chronic hepatitis C patients with near normal alanine aminotransferase levels

Crossbred Sows Fed a Western Diet during Pre-Gestation, Gestation, Lactation, and Post-Lactation Periods Develop Signs of Lean Metabolic Syndrome That Are Partially Attenuated by Spirulina Supplementation

Excessive dietary intake of fats and sugars (“Western diet”, WD) is one of the leading causes of obesity. The consumption of the microalga Arthrospira platensis (spirulina, Sp) is increasing due to its presumed health benefits. Both WD and Sp are also consumed by pregnant and breastfeeding women. This study investigated if gestating and lactating domestic pigs are an appropriate model for WD-induced metabolic disturbances similar to those observed in humans and if Sp supplementation may attenuate any of these adverse effects. Pigs were fed a WD high in fat, sugars, and cholesterol or a control diet. Half of the animals per diet group were supplemented with 20 g Sp per day. The WD did not increase body weight or adipose tissue accumulation but led to metabolic impairments such as higher cholesterol concentration in plasma, lower IGF1 plasma levels, and signs of hepatic damage compared to the control group. Spirulina supplementation could not reduce all the metabolic impairments observed in WD-fed animals. These findings indicate limited suitability of gestating and lactating domestic pigs as a model for WD but a certain potential of low-dose Sp supplementation to partially attenuate negative WD effects.

Expression of glutathione S-transferase A1, a phase II drug-metabolizing enzyme in acute hepatic injury on mice

In the present study, three models of acute liver injury in mice were induced via the administration of CCl₄ (35 mg/kg, 24 h), acetyl-para-aminophenol (APAP; 200 mg/kg, 12 h) and ethanol (14 ml/kg, 8 h) to study the effect of glutathione S-transferase A1 (GSTA1) on acute liver injury. The serum levels of alanine transaminase, aspartate transaminase and liver homogenate indicators (superoxide dismutase, glutathione and glutathione peroxidase) were significantly lower in model groups compared with the control group (P<0.01), whereas the liver homogenate indicator malondialdehyde was significantly increased (P<0.01). The expression of GSTA1 in liver was significantly decreased in the model groups compared with the control group (P<0.01). GSTA1 protein content was 3.8, 1.3 and 2.6 times lower in the CCl_4, APAP and ethanol model groups, respectively. Furthermore, GSTA1 mRNA expression levels decreased by 4.9, 2.1 and 3.7 times in the CCl_4, APAP and ethanol model groups, respectively. Among the three models, the injury induced by CCl₄ was the most marked, followed by ethanol and finally APAP. These results suggest that GSTA1 may be released by the liver and serve as an antioxidant in the prevention of liver damage.

Significance of Serum Alpha-Glutathione S-Transferase Assessment in Hepatitis C Patients with Different Alanine Aminotransferase Patterns

BACKGROUND

Alpha-Glutathione S-transferase (α-GST) is a liver enzyme which showed properties making it useful in assessment of liver cell damage. A number of studies demonstrated its early elevation in different hepatic insults, but its pattern in HCV was controversial. Consequently, we planned this work to study the significance of Serum Alpha-Glutathione S-Transferase (α-GST) assessment in hepatitis C patients with different alanine aminotransferase (ALT) patterns.

METHODS

Sixty-five untreated male patients with history of hepatitis C virus (HCV) positive antibodies and 21 healthy age- and sex-matched control subjects were enrolled in this study. Sera were collected for confirmation of the presence of HCV antibodies (by ELISA) as well as for assessment of the levels of α-GST, ALT, aspartate aminotransferase, alkaline phosphatase, gamma glutamyl-transferase, total proteins, albumin and HCV RNA. HCV RNA was detected by the reverse transcription polymerase chain reaction (RT-PCR). Based on ALT level, patients were divided into three groups. Twelve patients with normal ALT levels (NALT), 29 with near normal ALT levels (NNALT), and 24 with high ALT levels (HALT). All data were statistically analyzed for significance and correlation as well as sensitivity, specificity, positive and negative predictive values.

RESULTS

The mean value of α-GST in HCV patients was significantly higher compared to the control with 82% sensitivity, 85% specificity, 98% positive predictive value and 63% negative predictive value. These results were more or less similar to the results of ALT and higher than the results of all the other assayed liver function tests. The sensitivity, and positive and negative predictive values of α-GST were lower than aminotransferases, but higher than the other assayed liver function tests in NNALT and HALT groups. Nevertheless, in NALT, these parameters were higher for α-GST than all the other assayed liver function tests including aminotransferases.

CONCLUSIONS

Assay of α-GST has an adjuvant in evaluation of liver cell damage in HCV patients. However, its role is much more valuable in patients with normal aminotransferases for early detection of liver cell damage.

No elevation of glutathione S-transferase-a1-1 by amiodarone loading in intensive care unit patients with atrial fibrillation

Hepatocellular toxicity is a putative side-effect of amiodarone. The hepatic detoxification enzyme glutathione S-transferase-A1-1 (GSTA1-1) is a sensitive indicator of hepatocellular damage. We investigated the occurrence of subclinical liver injury, as measured by plasma GSTA1-1 in intensive care unit patients with atrial fibrillation receiving amiodarone. Sixteen haemodynamically stable intensive care unit patients with atrial fibrillation were treated with amiodarone intravenously. Patients were given a loading dose of 150 mg followed by another 150 mg followed by a continuous infusion of 1200 mg/hour if atrial fibrillation persisted. Blood samples for GSTA1-1 (measured by an enzyme-linked immunosorbent assay) were taken at zero, one, three, six, 12 and 24 hours, transaminases and bilirubin at zero, six, 12 and 24 hours. Blood pressure and heart rate were continuously monitored. Effects were analysed for time-dependent changes (one-way analysis of variance for repeated measures). Blood pressure increased from 125 +/- 8/60 +/- 3 mmHg at t = 0 to 144 +/- 9/66 +/- 4 mmHg at t = 24 hours (P < 0.05), heart rate decreased from atrial fibrillation 124 +/- 5 to sinus rhythm 86 +/- 6 beats per minute (P < 0.05). There was no significant elevation of GSTA1-1, transaminases or bilirubin during the observation period of 24 hours. Amiodarone does not cause elevation of GSTA1-1 as a marker of subclinical liver injury in haemodynamically stable intensive care unit patients with atrial fibrillation.

Evaluation of alpha-glutathione-S-transferase as a biomarker of lamivudine therapy for chronic hepatitis B

Hepatic damage associated with chronic hepatitis B (CHB) relies on measurement of serum transaminases and asssessment of hepatic histology. We determined if serum hepatic function tests, including alpha-glutathione-S-transferase ((GST), were of value in monitoring or predicting the effect of lamivudine therapy for CHB. Thirty-nine patients received orally 100 mg of lamivudine daily for 48 weeks. Blood samples were obtained at baseline and at 24 and 48 weeks. At the end of the treatment period the patients were then divided into four groups according to the pattern of HBs and HBe antigens. At baseline and at 24 weeks ALT, AST, and (GST had lower values in the complete response compared to the complete failure groups. Using ROC analysis, only ALT at 24 weeks (area under the curve = 0.803) had significant diagnostic ability in detecting responders. These results reaffirm the value of measuring serum ALT as an indicator of treatment response and provide information on the potential use of (GST as an additional prognostic biomarker in this patient group.

Modification of N‐Acetyltransferases and Glutathione S‐Transferases by Coffee Components: Possible Relevance for Cancer Risk

Enzymes of xenobiotic metabolism are involved in the activation and detoxification of carcinogens and can play a pivotal role in the susceptibility of individuals toward chemically induced cancer. Differences in such susceptibility are often related to genetically predetermined enzyme polymorphisms but may also be caused by enzyme induction or inhibition through environmental factors or in the frame of chemopreventive intervention. In this context, coffee consumption, as an important lifestyle factor, has been under thorough investigation. Whereas the data on a potential procarcinogenic effect in some organs remained inconclusive, epidemiology has clearly revealed coffee drinkers to be at a lower risk of developing cancers of the colon and the liver and possibly of several other organs. The underlying mechanisms of such chemoprotection, modifications of xenobiotic metabolism in particular, were further investigated in rodent and in vitro models, as a result of which several individual chemoprotectants out of the >1000 constituents of coffee were identified as well as some strongly metabolized individual carcinogens against which they specifically protected. This chapter discusses the chemoprotective effects of several coffee components and whole coffee in association with modifications of the usually protective glutathione-S-transferase (GST) and the more ambivalent N-acetyltransferase (NAT). A key role is played by kahweol and cafestol (K/C), two diterpenic constituents of the unfiltered beverage that were found to reduce mutagenesis/tumorigenesis by strongly metabolized compounds, such as 2-amino-1-methyl-6-phenylimidazo-[4,5-b]pyridine, 7,12-dimethylbenz[a]anthracene, and aflatoxin B(1), and to cause various modifications of xenobiotic metabolism that were overwhelmingly beneficial, including induction of GST and inhibition of NAT. Other coffee components such as polyphenols and K/C-free coffee are also capable of increasing GST and partially of inhibiting NAT, although to a somewhat lesser extent.

Protection of antioxidants compound of Chinese drug on liver oxidative injury by local 60Co irradiation in rats with tumor

AIM: To observe the oxidative injury of livers induced by local irradiation and the protection of antioxidants compound of Chinese drug in rats with tumor.

METHODS: The Spraue-Dawley (SD) rats were divided into negative control group and trial groups. The tumor cells (Walker-256) were injected into the rat to get the solid tumor, which was then cut into small pieces to be embedded into the right rear buttocks under skin of rats. As the embedded tumor grew up successfully, the rats with solid tumor were randomly divided into 3 groups, i.e. tumor group, irradiative group and protective group. The protective group was given antioxidants compound by gavage and other groups were given the same dosage water. The irradiative group and the protective group were locally g-irradiated with the total doses of 47Gy, then all the rats were killed, the serum and livers were collected to measure the content of malondialdehyde (MDA), the activities of glutathione S-transferase (GST), total superoxide dismutase (T-SOD), manganese superoxide dismutase (Mn-SOD), the total antioxidant capacity (TAC), nitric oxide (NO), nitric oxide synthase (NOS) and the total proteins.

RESULTS: The activities of serum and liver GST (mkat/L and mkat/g) and the content of MDA (in liver protein, nmoL/g) in irradiative group were much higher than those in all the other groups (479±17 vs 427±59 and 421±36, 50.3±1.0 vs 46.8±2.3 and 47.5 ±1.0, 33.7±8.8 vs 21.4±7.2 and 21.7±6.8, P <0.05, P <0.01, P <0.01,respectively). The activities of T-SOD (in liver protein, mkat/g), Mn-SOD (in liver protein, mkat/g), GSH (in liver protein, mg/g) and TAC (in liver protein, mkat/g) in irradiative group were much lower than those in other groups (39.3±7.0 vs 48.8±2.8 and 47.7±4.3, 18.7 ±6.2 vs 28.8 ±2.5 and 28.2±7.7, 0.44±0.13 vs 0.57±0.06 and 0.61±0.22, 20.7± 5.3 vs 26.5 ±3.3 and 26.3±1.7, P <0.01, P <0.01, P <0.01, P <0.05, respectively).The content of NO (in liver protein, mmoL/g) in irradiative group increased significantly, the activity (in liver protein, mkat/g) of NOS also increased significantly than those in the control group (1.22 ±0.08 vs 0.98± 0.15, 4.92 ±0.94 vs 3.63± 0.77, P <0.01, P <0.05, respectively). The content of NO and the activity of NOS in protective group decreased markedly than those in irradiative group(0.77±0.22 vs 1.22 ±0.08, 3.62 ±0.49 vs 4.92±0.94, P <0.01, P <0.05, respectively).

CONCLUSION: Local irradiation can cause the oxidative injury on liver of the rats and the antioxidant compound shows good protective effect against this injury by increasing the activities of antioxidants and decreasing the content of NO, the activity and expression of NOS, which give us a new way to reduce the side effect during the radiotherapy.

Oxidative stress in viral and alcoholic hepatitis

Liver damage ranges from acute hepatitis to hepatocellular carcinoma, through apoptosis, necrosis, inflammation, immune response, fibrosis, ischemia, altered gene expression and regeneration, all processes that involve hepatocyte, Kupffer, stellate, and endothelial cells. Reactive oxygen and nitrogen species (ROS, RNS) play a crucial role in the induction and in the progression of liver disease, independently from its etiology. They are involved in the transcription and activation of a large series of cytokines and growth factors that, in turn, can contribute to further production of ROS and RNS. The main sources of free radicals are represented by hepatocyte mitochondria and cytochrome p450 enzymes, by endotoxin-activated macrophages (Kupffer cells), and by neutrophils. The consequent alteration of cellular redox state is potentiated by the correlated decrease of antioxidant and energetic reserves. Indices of free radical-mediated damage, such as the increase of malondialdehyde, 4-hydroxynonenal, protein-adducts, peroxynitrite, nitrotyrosine, etc., and/or decrease of glutathione, vitamin E, vitamin C, selenium, etc., have been documented in patients with viral or alcoholic liver disease. These markers may contribute to the monitoring the degree of liver damage, the response to antiviral therapies and to the design of new therapeutic strategies. In fact, increasing attention is now paid to a possible "redox gene therapy." By enhancing the antioxidant ability of hepatocytes, through transgene vectors, one could counteract oxidative/nitrosative stress and, in this way, contribute to blocking the progression of liver disease.

13C-aminopyrine breath test to evaluate severity of disease in patients with chronic hepatitis C virus infection

BACKGROUND

There are few data on the use of the 13C-aminopyrine breath test to evaluate the severity of disease in patients with hepatitis C virus-related chronic liver disease, although these patients represent one of the most important problems in clinical hepatology.

AIMS

To compare 13C-aminopyrine breath test results of patients with hepatitis C virus-related chronic hepatitis and Child-Pugh class A cirrhosis with those of normal subjects, and to evaluate different methods of expressing 13C-aminopyrine breath test results.

METHODS

Twenty-four patients with hepatitis C virus-related chronic hepatitis and 17 patients with Child-Pugh class A cirrhosis underwent 13C-aminopyrine breath test. Breath samples were collected every 30 min up to 2 h after 13C-aminopyrine administration. 13C-Aminopyrine breath test results were expressed as a percentage of the administered dose of 13C recovered per hour (% dose/h) and the cumulative percentage of administered dose of 13C recovered over time (% dose cum). Nineteen healthy subjects served as controls. Patients with hepatitis C virus-related chronic hepatitis were divided into subgroups on the basis of histological staging and grading.

RESULTS

The 13C-aminopyrine breath test result (% dose/h) at 30 min was significantly different among the three subgroups of subjects (normal subjects, 11.5 +/- 3.5; chronic hepatitis patients, 8.1 +/- 4.1; cirrhosis patients, 5.0 +/- 3.1; P < 0.0005). Moreover, the differences between chronic hepatitis and cirrhosis patients were statistically significant (P < 0.03). The fibrosis score showed a significant inverse correlation with the 13C-aminopyrine breath test result (% dose/h) at 30 min (rs=- 0.409, P=0.05). The 13C-aminopyrine breath test result (% dose/h) at 30 min also allowed normal subjects and chronic hepatitis patients with low (< or = 2) or high (> 2) fibrosis scores to be distinguished. The 13C-aminopyrine breath test results (% dose cum) at 30, 60 and 90 min allowed discrimination between normal subjects and chronic hepatitis and cirrhosis patients. The 13C-aminopyrine breath test result (% dose cum) was also able to distinguish between normal subjects and chronic hepatitis patients with high but not low fibrosis scores. Both 13C-aminopyrine breath test results (% dose/h and % dose cum) at 120 min allowed the differentiation between normal subjects and chronic hepatitis patients with high (> or = 6) necro-inflammatory activity.

CONCLUSIONS

In patients with hepatitis C virus-related chronic liver disease, the 13C-aminopyrine breath test proved to be safe and easy to perform, and was able to evaluate different degrees of liver function impairment which were partly correlated to clinical and histological evaluation. In future studies, 13C-aminopyrine breath test results should be expressed in a standardized fashion to permit comparison.

Strategic importance of research support through pathology

The pace at which new drug candidates are being identified by Discovery Research demands that they be screened for preclinical attributes rapidly and efficiently. The early identification and elimination of compounds with toxic liabilities will produce safer drugs in a shorter time period, and with an increased rate of success. Most major pharmaceutical companies now recognize the strategic role of pathology support for research and have developed specific units to effect this outcome. The early interaction of these pathologists with drug discovery teams to identify compounds with toxic liabilities is critical. Approaches being used include high throughput in vitro screens to predict the relative toxicity of discovery compounds and to provide early indications of underlying mechanisms, target profiling to predict consequences of receptor-ligand interactions at other-than-indicated target sites, and acute in vivo studies to establish tolerability limits and target organs of toxicity. These approaches include the application of contemporary tools such as genomics, proteomics, metabonomics, and genetically engineered animal models. To maximize the benefit of discovery pathology, it is critical that pharmaceutical companies also actively participate in non-proprietary knowledge sharing and the education of pathologists and toxicologists to lead these efforts in the future.