Hydrogen sulfide attenuates carbon tetrachloride-induced hepatotoxicity, liver cirrhosis and portal hypertension in rats

BACKGROUND : Hydrogen sulfide (H(2)S) displays vasodilative, anti-oxidative, anti-inflammatory and cytoprotective activities. Impaired production of H(2)S contributes to the increased intrahepatic resistance in cirrhotic livers. The study aimed to investigate the roles of H(2)S in carbon tetrachloride (CCl(4))-induced hepatotoxicity, cirrhosis and portal hypertension.

METHODS AND FINDINGS : Sodium hydrosulfide (NaHS), a donor of H(2)S, and DL-propargylglycine (PAG), an irreversible inhibitor of cystathionine γ-lyase (CSE), were applied to the rats to investigate the effects of H(2)S on CCl(4)-induced acute hepatotoxicity, cirrhosis and portal hypertension by measuring serum levels of H(2)S, hepatic H(2)S producing activity and CSE expression, liver function, activity of cytochrome P450 (CYP) 2E1, oxidative and inflammatory parameters, liver fibrosis and portal pressure. CCl(4) significantly reduced serum levels of H(2)S, hepatic H(2)S production and CSE expression. NaHS attenuated CCl(4)-induced acute hepatotoxicity by supplementing exogenous H(2)S, which displayed anti-oxidative activities and inhibited the CYP2E1 activity. NaHS protected liver function, attenuated liver fibrosis, inhibited inflammation, and reduced the portal pressure, evidenced by the alterations of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), hyaluronic acid (HA), albumin, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6 and soluble intercellular adhesion molecule (ICAM)-1, liver histology, hepatic hydroxyproline content and α-smooth muscle actin (SMA) expression. PAG showed opposing effects to NaHS on most of the above parameters.

CONCLUSIONS :  Exogenous H2S attenuates CCl4-induced hepatotoxicity, liver cirrhosis and portal hypertension by its multiple functions including anti-oxidation, anti-inflammation, cytoprotection and anti-fibrosis, indicating that targeting H2S may present a promising approach, particularly for its prophylactic effects, against liver cirrhosis and portal hypertension.

Gene profiling reveals hydrogen sulphide recruits death signaling via the N-methyl-D-aspartate receptor identifying commonalities with excitotoxicity

Recently the role of hydrogen sulphide (H₂S) as a gasotransmitter stimulated wide interest owing to its involvement in Alzheimer's disease and ischemic stroke. Previously we demonstrated the importance of functional ionotropic glutamate receptors (GluRs) by neurons is critical for H₂S-mediated dose- and time-dependent injury. Moreover N-methyl-D-aspartate receptor (NMDAR) antagonists abolished the consequences of H₂S-induced neuronal death. This study focuses on deciphering the downstream effects activation of NMDAR on H₂S-mediated neuronal injury by analyzing the time-course of global gene profiling (5, 15, and 24 h) to provide a comprehensive description of the recruitment of NMDAR-mediated signaling. Microarray analyses were performed on RNA from cultured mouse primary cortical neurons treated with 200 µM sodium hydrosulphide (NaHS) or NMDA over a time-course of 5–24 h. Data were validated via real-time PCR, western blotting, and global proteomic analysis. A substantial overlap of 1649 genes, accounting for over 80% of NMDA global gene profile present in that of H₂S and over 50% vice versa, was observed. Within these commonly occurring genes, the percentage of transcriptional consistency at each time-point ranged from 81 to 97%. Gene families involved included those related to cell death, endoplasmic reticulum stress, calcium homeostasis, cell cycle, heat shock proteins, and chaperones. Examination of genes exclusive to H₂S-mediated injury (43%) revealed extensive dysfunction of the ubiquitin-proteasome system. These data form a foundation for the development of screening platforms and define targets for intervention in H₂S neuropathologies where NMDAR-activated signaling cascades played a substantial role. J. Cell. Physiol. 226: 1308–1322, 2011.

Somatization, but not depression, is characterized by disorders in the tryptophan catabolite (TRYCAT) pathway, indicating increased indoleamine 2,3-dioxygenase and lowered kynurenine aminotransferase activity

BACKGROUND: Reduced plasma tryptophan occurs in depression and somatization. Induction of indoleamine 2,3-dioxygenase (IDO) with consequent synthesis of tryptophan catabolites (TRYCATs) and lowered tryptophan are associated with the onset of depression in the puerperium and during interferon-alpha treatment. Depression is accompanied by lowered kynurenic acid, a neuroprotectant, or increased kynurenine, a neurotoxic TRYCAT.

AIMS AND METHODS: To examine plasma tryptophan; kynurenine; kynurenic acid; the kynurenine / tryptophan (KY/TRP) ratio, indicating IDO activity; and the kynurenine / kynurenic acid (KY/KA) ratio, indicating kynurenine aminotransferase (KAT) activity, in somatization; depression; somatization + depression; and controls. Illness severity is measured by the Somatic Symptom Index (SSI), the Screening for Somatoform Symptoms (SOMS), and the Beck Depression Inventory (BDI).

RESULTS: Tryptophan is significantly lower in patients than in controls and lower in somatization than in depression. KY/TRP is significantly increased in somatization. Kynurenic acid is significantly lower in patients than in controls, and lower in somatization than in depression. KY/KA is significantly higher in somatization and somatization + depression than in depression and controls. There are significant correlations between the severity of somatization, but not depression, and KY/TRP and KY/KA (positive) and tryptophan (negative). Kynurenine and kynurenic acid are significantly correlated in controls, somatization + depression, and depression, but not in somatization.

CONCLUSIONS: Somatization is characterized by increased IDO activity and disorders in KAT activity and an increased neurotoxic potential. The TRYCAT pathway may play a role in the pathophysiology of somatizing and “psychosomatic” symptoms through effects on pain, gut motility, the autonomic nervous system, peripheral NMDA receptors, etc. Even more, biological disorders, such as aberrations in the TRYCAT pathway, which are considered to be a hallmark for depression, are in fact attributable to somatization rather than to depression per se. Future research in depression on the TRYCAT pathway should always control for the possible effects of somatization.

Functional (GT)n polymorphisms in promoter region of N-methyl-d-aspartate receptor 2A subunit (GRIN2A) gene affect hippocampal and amygdala volumes

The glutamate system including N-methyl-d-aspartate (NMDA) affects synaptic formation, plasticity and maintenance. Recent studies have shown a variable (GT)n polymorphism in the promoter region of the NMDA subunit gene (GRIN2A) and a length-dependent inhibition of transcriptional activity by the (GT)n repeat. In the present study, we examined whether the GRIN2A polymorphism is associated with regional brain volume especially in medial temporal lobe structures, in which the NMDA-dependent synaptic processes have been most extensively studied. Gray matter regions of interest (ROIs) for the bilateral amygdala and hippocampus were outlined manually on the magnetic resonance images of 144 healthy individuals. In addition, voxel-based morphometry (VBM) was conducted to explore the association of genotype with regional gray matter volume from everywhere in the brain in the same sample. The manually measured hippocampal and amygdala volumes were significantly larger in subjects with short allele carriers (n = 89) than in those with homozygous long alleles (n = 55) when individual differences in intracranial volume were accounted for. The VBM showed no significant association between the genotype and regional gray matter volume in any brain region. These findings suggest that the functional GRIN2A (GT)n polymorphism could weakly but significantly impact on human medial temporal lobe volume in a length-dependent manner, providing in vivo evidence of the role of the NMDA receptor in human brain development.

Sustained weight loss in obese subjects has benefits that are independent of attained weight

Objective: To explore the hypothesis that sustained weight loss in severely obese patients may have benefits that are independent of their attained BMI. Research Methods and Procedures: We conducted a comparison of two weight-stable groups with BMI in the 30 to 35 kg/m2 range. Subjects (n = 79) were selected obese patients 3 years after laparoscopic adjustable gastric band surgery, and controls (n = 79) were obese patients seeking weight loss therapy. Subjects were selected in a de-identified manner from our database to best match the control group. A range of clinical, biochemical, and questionnaire measures were obtained to assess obesity-related health status Results: Subjects maintained a mean weight loss of 32.8 plusminus 18 kg after surgery. The weight loss subjects had significantly lower fasting plasma glucose, insulin, and triglyceride concentrations, along with higher high-density lipoprotein-cholesterol levels and better indirect measures of insulin sensitivity when compared with controls (p < 0.05 for all). In addition, aminotransferase levels, neutrophil counts, and globulin levels were also significantly lower in weight loss subjects. All differences in laboratory variables remained significant after controlling for BMI. The subjects also reported better health-related quality of life, fewer symptoms of depression, and greater satisfaction with their appearance than controls. Discussion: These findings suggest that the post-weight loss state conveys benefits that are greater than predicted by the attained BMI. These findings may have important implications regarding the expectations of weight loss therapy, and mechanisms for this effect should be carefully sought.

Inflammation, hepatic enzymes and resistance training in individuals with metabolic risk factors

Aims Increases in inflammatory markers, hepatic enzymes and physical inactivity are associated with the development of the metabolic syndrome (MetS). We examined whether inflammatory markers and hepatic enzymes are correlated with traditional risk factors for MetS and studied the effects of resistance training (RT) on these emerging risk factors in individuals with a high number of metabolic risk factors (HiMF, 2.9 ± 0.8) and those with a low number of metabolic risk factors (LoMF, 0.5 ± 0.5).

Methods Twenty-eight men and 27 women aged 50.8 ± 6.5 years (mean ± sd) participated in the study. Participants were randomized to four groups, HiMF training (HiMFT), HiMF control (HiMFC), LoMF training (LoMFT) and LoMF control (LoMFC). Before and after 10 weeks of RT [3 days/week, seven exercises, three sets with intensity gradually increased from 40–50% of one repetition maximum (1RM) to 75–85% of 1RM], blood samples were obtained for the measurement of pro-inflammatory cytokines, C-reactive protein (CRP), -glutamyltransferase (GGT) and alanine aminotransferase (ALT).

Results At baseline, HiMF had higher interleukin-6 (33.9%), CRP (57.1%), GGT (45.2%) and ALT (40.6%) levels, compared with LoMF (all P < 0.05). CRP, GGT and ALT correlated with the number of risk factors (r = 0.48, 0.51 and 0.57, respectively, all P < 0.01) and with other anthropometric and clinical measures (r range from 0.26 to 0.60, P < 0.05). RT did not significantly alter inflammatory markers or hepatic enzymes (all P > 0.05).

Conclusions HiMF was associated with increased inflammatory markers and hepatic enzyme concentrations. RT did not reduce inflammatory markers and hepatic enzymes in individuals with HiMF.

Redox voltammetry of sub-parts per billion levels of Cu2+ at polyaspartate-modified gold electrodes

An electrochemical sensor for the detection of Cu2+ is reported which incorporates poly-l-aspartic acid (PLAsp) with 32–96 aspartate units as a selective ligand for the metal ion. PLAsp is covalently attached to a gold electrode modified with a monolayer of 3-mercaptopropionic acid using carbodiimide coupling via an N-hydroxysuccinimide (NHS) ester intermediate. The acid side groups and deprotonated peptide nitrogens on two aspartate moieties are thought to be primarily responsible for chelation of Cu2+, which remains bound when reduced to Cu+. A consequence of the multiple binding points that are available with a polypeptide is the low detection limit. The lowest concentration detected was 3 nM (0.2 ppb) achieved with Osteryoung square wave voltammetry. This detection limit compares favourably with that of ICP-OES and previously reported cysteine-modified electrodes. Analysis of tap and lake water samples using the PLAsp-modified electrode agreed well with ICP-OES analysis of the same samples.

Metabolite profiles in the anterior cingulate cortex of depressed patients differentiate those taking N-acetyl-cysteine versus placebo

Background: Increased oxidative stress is thought to contribute to the pathophysiology of major depressive disorder (MDD), which is in part due to diminished levels of glutathione, the primary anti-oxidant of the brain. Oral administration of N-acetyl-cysteine (NAC) replenishes glutathione and has therefore been shown to reduce depressive symptoms. Proton magnetic spectroscopy (1H-MRS) that allows quantification of brain metabolites pertinent to both MDD and oxidative biology may provide some novel insights into the neurobiological effects of NAC, and in particular metabolite concentrations within the anterior cingulate cortex (ACC) are likely to be important given the key role of this region in the regulation of affect.

Objective: The aim of this study was to determine whether the metabolite profile of the ACC in MDD patients predicts treatment with adjunctive NAC versus placebo.

Methods: This study was nested within a multicentre, randomized, double-blind, placebo-controlled study of MDD participants treated with adjunctive NAC. Participants (n = 76) from one site completed the spectroscopy component at the end of treatment (12 weeks). Spectra from a single-voxel in the ACC were acquired and absolute concentrations of glutamate (Glu), glutamate-glutamine (Glx), N-acetyl-aspartate (NAA) and myo-inositol (mI) were obtained. Binary logistic regression analysis was performed to determine whether metabolite profiles could predict NAC versus placebo group membership.

Results: When predicting group outcome (NAC or placebo), Glx, NAA and mI were a significant model, and had 75% accuracy, while controlling for depression severity and sex. However, the Glu, NAA and mI profile was only predictive at a trend level, with 68.3% accuracy. For both models, the log of the odds of a participant being in the NAC group was positively related to NAA, Glx and Glu levels and negatively related to mI levels.

Conclusion: The finding of higher Glx and NAA levels being predictive of the NAC group provides preliminary support for the putative anti-oxidative role of NAC in MDD.

Entecavir for the treatment of chronic hepatitis B infection

This paper presents a summary of the evidence review group (ERG) report into the clinical and cost-effectiveness of entecavir for the treatment of chronic hepatitis B (CHB) in adults based upon a review of the manufacturer's submission to the National Institute for Health and Clinical Excellence (NICE) as part of the single technology appraisal (STA) process. The submission's evidence came from five randomised controlled trials (RCTs), of good methodological quality and measuring a range of clinically relevant outcomes, comparing entecavir with lamivudine. After 1 year of treatment entecavir was statistically superior to lamivudine in terms of the proportion of patients achieving hepatitis B virus (HBV) DNA suppression, alanine aminotransferase (ALT) normalisation and histological improvement, but not in terms of the proportion of patients achieving hepatitis B e antigen (HBeAg) seroconversion. The incidence of adverse or serious adverse events was similar for both treatments. The results of the manufacturer's mixed treatment comparison (MTC) model to compare entecavir with the comparator drugs in nucleoside-naive patients were considered to be uncertain because of concerns over its conduct and reporting. For the economic evaluation the manufacturer constructed two Markov state transition models, one in HBeAg-positive and one in HBeAg-negative patients. The modelling approach was considered reasonable subject to some uncertainties and concerns over some of the structural assumptions. In HBeAg-positive patients the base-case incremental cost-effectiveness ratios (ICER) for entecavir compared with lamivudine and pegylated interferon alpha-2a were 14,329 pounds and 8403 pounds per quality-adjusted life-year (QALY) respectively. Entecavir was dominated by telbivudine. In HBeAg-negative patients the base-case ICERs for entecavir compared with lamivudine, pegylated interferon alpha-2a and telbivudine were 13,208 pounds, 7511 pounds and 6907 pounds per QALY respectively. In HBeAg-positive lamivudine-refractory patients entecavir dominated adefovir added to lamivudine. In one-way deterministic sensitivity analysis on all key input parameters for entecavir compared with lamivudine in nucleoside-naive patients, ICERs generally remained under 30,000 pounds per QALY. In probabilistic sensitivity analysis in nucleoside-naive HBeAg-positive patients the probability of the ICER for entecavir being below 20,000 pounds per QALY was 57%, 82% and 45% compared with lamivudine, pegylated interferon alpha-2a and telbivudine respectively. In nucleoside-naive HBeAg-negative patients the probabilities were 90%, 100% and 96% respectively. The manufacturer's lifetime treatment scenario for HBeAg-negative patients and the ERG's 20-year treatment scenario for HBeAg-positive patients increased the ICERs, particularly in the latter case. Amending the HBeAg-negative model so that patients with compensated cirrhosis would also receive lifetime treatment gave probabilities of entecavir being cost-effective at a willingness to pay of 20,000 pounds and 30,000 pounds of 4% and 40% respectively. The NICE guidance issued in August 2008 as a result of the STA states that entecavir is recommended as an option for the treatment of people with chronic HBeAg-positive or HBeAg-negative hepatitis B in whom antiviral treatment is indicated.

The integrative management of treatment-resistant depression: a comprehensive review and perspectives.

Major depressive disorder is a prevalent and disabling illness. Notwithstanding numerous advances in the pharmacological treatment of depression, approximately 70% of patients do not remit after first-line antidepressant treatment.

Platelet glutamate receptor supersensitivity in major depressive disorder.

Dysregulation of glutamate has been described in depression, and supersensitivity of platelet glutamate receptors has been found in both psychotic major depression and schizophrenia. The aim of this study was to examine the platelet glutamate receptor sensitivity in patients with nonpsychotic, unipolar major depression to assess whether this is a marker of depression or of psychosis. Glutamate receptor sensitivity was assessed using the platelet intracellular calcium response to glutamate (0-100 micromol) measured by spectrofluorometry. The depression group showed a significantly greater platelet intracellular calcium response to glutamate stimulation than the control group, both in terms of absolute values (p = 0.007) and percentage of response from baseline (p = 0.030). These data suggest that platelet glutamate receptors may be supersensitive in depression and that the platelet may be a possible peripheral marker of glutamate function in depression.

Supersensitive platelet glutamate receptors as a possible peripheral marker in schizophrenia.

Hypoglutamatergic function is implicated in the pathogenesis of schizophrenia. The aim of this study was to examine the platelet intracellular calcium response to glutamate using spectroflourometry in 15 schizophrenic patients and 15 matched control individuals as an index of platelet glutamate receptor sensitivity. Patients with schizophrenia had significantly lower baseline intracellular calcium levels than matched control individuals (P = 0.03). The percentage response of the schizophrenic individuals to glutamate stimulation was significantly greater than control individuals (P < 0.001). These data suggest that platelet glutamate receptors may be supersensitive in schizophrenia. Furthermore, the platelet may be a possible peripheral marker of glutamate function in schizophrenia.

Nanoformulated mutant SurR9-C84A: a possible key for alzheimer's and its associated inflammation

PURPOSE: Alzheimer's disease (AD) is one of the untreatable neurodegenerative diseases characterised by the pathologic amyloid plaque deposition and inflammation. The aim of this study is to evaluate the neuroprotective effects of nanoformulated SurR9-C84A, a survivin mutant belonging to the inhibitors of the apoptosis (IAP) protein family. The effect of SurR9-C84A was studied against the β-amyloid toxicity and various inflammatory insults in the differentiated SK-N-SH neurons. METHOD: SurR9-C84A loaded poly(lactic-co-glycolic acid) nanoparticles were prepared following the modified double emulsion technique. The neuroprotective effect of SurR9-C84A was evaluated against the amyloid-β (Aβ) peptide fragment, N-methyl-D-aspartate (NMDA) toxicity and the inflammatory assaults. To mimic the in vivo situation, a co-culture of neurons and microglia was also studied to validate these results. RESULTS: SurR9-C84A treatments showed improved neuronal health following Aβ, and NMDA toxicity in addition to inflammatory insults induced in mono and co-cultures. The neuroprotective effect was evident with the reduced neuronal death, accelerated expression of neuronal integrity markers (neurofilaments, beta-tubulin III etc.,) and the neuroprotective ERK/MAPK signalling. CONCLUSION: The current results demonstrated that the SurR9-C84A nanoformulation was very effective in rescuing the neurons and holds a potential future application against AD.

Peripheral proinflammatory markers associated with ketamine response in a preclinical model of antidepressant-resistance

© 2015 Elsevier B.V. Ketamine, N-methyl- d-aspartate (NMDA) receptor antagonist and anti-inflammatory agent, has rapid therapeutic effects in a subset of patients with more intractable forms of depression. Irregular proinflammatory cytokine and acute-reactive protein levels have been reported in clinical and preclinical depression research. We explored the association between the rapid antidepressant-like effects of ketamine and peripheral proinflammatory profile in a model of antidepressant-resistance. Male Wistar rats were pre-treated with ACTH-(1-24) 100. μg/d or saline (0.9%) for 14. d. Antidepressant-like effects were assessed with the forced swim test (FST). Ketamine (10. mg/kg) significantly reduced immobility duration in saline-pretreated control animals. In contrast, a divergent response was observed in ACTH-pretreated antidepressant resistant animals, with 50% responders and 50% non-responders. Plasma samples were analyzed via enzyme-linked immunosorbent assay (ELISA) for interleukin 6 (IL-6), tumour necrosis factor alpha (TNFα) and C-reactive protein (CRP). Levels of CRP and TNFα differentiated ketamine responders and non-responders.

Comparative microarray analysis identifies commonalities in neuronal injury: evidence for oxidative stress, dysfunction of calcium signalling, and inhibition of autophagy-lysosomal pathway

Mitochondrial dysfunction, ubiquitin-proteasomal system impairment and excitotoxicity occur during the injury and death of neurons in neurodegenerative conditions. The aim of this work was to elucidate the cellular mechanisms that are universally altered by these conditions. Through overlapping expression profiles of rotenone-, lactacystin- and N-methyl-D-aspartate-treated cortical neurons, we have identified three affected biological processes that are commonly affected; oxidative stress, dysfunction of calcium signalling and inhibition of the autophagic-lysosomal pathway. These data provides many opportunities for therapeutic intervention in neurodegenerative conditions, where mitochondrial dysfunction, proteasomal inhibition and excitotoxicity are evident.