The role of gut microbiota in cerebrovascular disease and related dementia.

In recent years, increasing evidence suggests that commensal microbiota may play an important role not only in health but also in disease including cerebrovascular disease. Gut microbes impact physiology, at least in part, by metabolizing dietary factors and host-derived substrates and then generating active compounds including toxins. The purpose of this current review is to highlight the complex interplay between microbiota, their metabolites. and essential functions for human health, ranging from regulation of the metabolism and the immune system to modulation of brain development and function. We discuss the role of gut dysbiosis in cerebrovascular disease, specifically in acute and chronic stroke phases, and the possible implication of intestinal microbiota in post-stroke cognitive impairment and dementia, and we identify potential therapeutic opportunities of targeting microbiota in this context. LINKED ARTICLES: This article is part of a themed issue From Alzheimer's Disease to Vascular Dementia: Different Roads Leading to Cognitive Decline. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v181.6/issuetoc.

Defective hippocampal neurogenesis underlies cognitive impairment by carotid stenosis-induced cerebral hypoperfusion in mice.

Chronic cerebral hypoperfusion due to carotid artery stenosis is a major cause of vascular cognitive impairment and dementia (VCID). Bilateral carotid artery stenosis (BCAS) in rodents is a well-established model of VCID where most studies have focused on white matter pathology and subsequent cognitive deficit. Therefore, our aim was to study the implication of adult hippocampal neurogenesis in hypoperfusion-induced VCID in mice, and its relationship with cognitive hippocampal deficits. Mice were subjected to BCAS; 1 and 3 months later, hippocampal memory and neurogenesis/cell death were assessed, respectively, by the novel object location (NOL) and spontaneous alternation performance (SAP) tests and by immunohistology. Hypoperfusion was assessed by arterial spin labeling-magnetic resonance imaging (ASL-MRI). Hypoperfused mice displayed spatial memory deficits with decreased NOL recognition index. Along with the cognitive deficit, a reduced number of newborn neurons and their aberrant morphology indicated a remarkable impairment of the hippocampal neurogenesis. Both increased cell death in the subgranular zone (SGZ) and reduced neuroblast proliferation rate may account for newborn neurons number reduction. Our data demonstrate quantitative and qualitative impairment of adult hippocampal neurogenesis disturbances associated with cerebral hypoperfusion-cognitive deficits in mice. These findings pave the way for novel diagnostic and therapeutic targets for VCID.

CPEB alteration and aberrant transcriptome-polyadenylation lead to a treatable SLC19A3 deficiency in Huntington's disease.

Huntington's disease (HD) is a hereditary neurodegenerative disorder of the basal ganglia for which disease-modifying treatments are not yet available. Although gene-silencing therapies are currently being tested, further molecular mechanisms must be explored to identify druggable targets for HD. Cytoplasmic polyadenylation element binding proteins 1 to 4 (CPEB1 to CPEB4) are RNA binding proteins that repress or activate translation of CPE-containing transcripts by shortening or elongating their poly(A) tail. Here, we found increased CPEB1 and decreased CPEB4 protein in the striatum of patients and mouse models with HD. This correlated with a reprogramming of polyadenylation in 17.3% of the transcriptome, markedly affecting neurodegeneration-associated genes including PSEN1, MAPT, SNCA, LRRK2, PINK1, DJ1, SOD1, TARDBP, FUS, and HTT and suggesting a new molecular mechanism in neurodegenerative disease etiology. We found decreased protein content of top deadenylated transcripts, including striatal atrophy­linked genes not previously related to HD, such as KTN1 and the easily druggable SLC19A3 (the ThTr2 thiamine transporter). Mutations in SLC19A3 cause biotin-thiamine­responsive basal ganglia disease (BTBGD), a striatal disorder that can be treated with a combination of biotin and thiamine. Similar to patients with BTBGD, patients with HD demonstrated decreased thiamine in the cerebrospinal fluid. Furthermore, patients and mice with HD showed decreased striatal concentrations of thiamine pyrophosphate (TPP), the metabolically active form of thiamine. High-dose biotin and thiamine treatment prevented TPP deficiency in HD mice and attenuated the radiological, neuropathological, and motor HD-like phenotypes, revealing an easily implementable therapy that might benefit patients with HD.

Non-malignant portal vein thrombosis in a cohort of cirrhotic patients: Incidence and risk factors.

AIM: Non-malignant portal vein thrombosis (PVT) is a complication of liver cirrhosis. The aim of this study was to evaluate the annual incidence of PVT and related risk factors. METHODS: We retrospectively reviewed clinical, laboratory, and radiological data collected prospectively from September 2016 to September 2017. A follow-up of 36 months was performed in a subset of patients to determine the cumulative incidence of PVT and related complications. RESULTS: The study included 567 patients. The incidence of PVT at 12, 24, and 36 months was 3.7%, 0.8%, and 1.4%, respectively. Patients with PVT were compared with patients without PVT, and showed differences in albumin (p = 0.04), aspartate aminotransferase (p = 0.04), hemoglobin (p = 0.01), and prothrombin activity (p = 0.01). The presence of hydropic decompensation (57.1% vs. 30.1%; p 0.004), gastroesophageal varices (76.2% vs. 39.5%; p = 0.05), variceal bleeding (52.4% vs. 22.7%; p < 0.001), hepatic encephalopathy (38.1% vs. 9.9%; p = 0.01), spontaneous bacterial peritonitis (9.5% vs. 1.7%; p < 0.001), and use of beta-blockers (71.4% vs. 27.7%; p < 0.001) were significantly associated. In the multivariate analysis, use of beta-blockers and hepatic encephalopathy appeared as risk factors, and high albumin levels a protective factor. CONCLUSIONS: The incidence of PVT was 3.7%. Beta-blockers and hepatic encephalopathy were risks factors. High albumin levels were a protective factor.

Adding Branched-Chain Amino Acids to an Enhanced Standard-of-Care Treatment Improves Muscle Mass of Cirrhotic Patients With Sarcopenia: A Placebo-Controlled Trial.

INTRODUCTION: The effect of branched-chain amino acid (BCAA) supplementation on muscle mass in patients with cirrhosis and sarcopenia is unknown. METHODS: This is a pilot, prospective, randomized, and double-blind study of a cohort of 32 patients with cirrhosis and sarcopenia diagnosed by computed tomography scan who underwent a nutritional and physical activity intervention for 12 weeks. They were divided into 2 groups (placebo: 17 patients; BCAA: 15 patients). The study protocol was registered at ClinicalTrials.gov (NCT04073693). RESULTS: Baseline characteristics were similar in both groups. After treatment, only the BCAA group presented a significant improvement in muscle mass (43.7 vs 46 cm2/m2; P = 0.023). Seventeen patients (63%) presented improvement in muscle mass overall, which was more frequent in the BCAA group (83.3 vs 46.7%; P = 0.056). Regarding frailty, there was a significant improvement in the Liver Frailty Index in the global cohort (n = 32) after the 12 weeks (4.2 vs 3.9; P < 0.001). This difference was significant in both groups: in the placebo group (4.2 vs 3.8; P < 0.001) and in the BCAA group (4.2 vs 3.9; P < 0.001). After treatment, the BCAA group had a higher increase in zinc levels than the placebo group (Δzinc: 12.3 vs 5.5; P = 0.026). In addition, there was a trend for greater improvement of albumin levels in the BCAA group (Δalbumin: 0.19 vs 0.04; P = 0.091). DISCUSSION: BCAA supplementation improves muscle mass in cirrhotic patients with sarcopenia.

Post-stroke Neurogenesis: Friend or Foe?

The substantial clinical burden and disability after stroke injury urges the need to explore therapeutic solutions. Recent compelling evidence supports that neurogenesis persists in the adult mammalian brain and is amenable to regulation in both physiological and pathological situations. Its ability to generate new neurons implies a potential to contribute to recovery after brain injury. However, post-stroke neurogenic response may have different functional consequences. On the one hand, the capacity of newborn neurons to replenish the damaged tissue may be limited. In addition, aberrant forms of neurogenesis have been identified in several insult settings. All these data suggest that adult neurogenesis is at a crossroads between the physiological and the pathological regulation of the neurological function in the injured central nervous system (CNS). Given the complexity of the CNS together with its interaction with the periphery, we ultimately lack in-depth understanding of the key cell types, cell-cell interactions, and molecular pathways involved in the neurogenic response after brain damage and their positive or otherwise deleterious impact. Here we will review the evidence on the stroke-induced neurogenic response and on its potential repercussions on functional outcome. First, we will briefly describe subventricular zone (SVZ) neurogenesis after stroke beside the main evidence supporting its positive role on functional restoration after stroke. Then, we will focus on hippocampal subgranular zone (SGZ) neurogenesis due to the relevance of hippocampus in cognitive functions; we will outline compelling evidence that supports that, after stroke, SGZ neurogenesis may adopt a maladaptive plasticity response further contributing to the development of post-stroke cognitive impairment and dementia. Finally, we will discuss the therapeutic potential of specific steps in the neurogenic cascade that might ameliorate brain malfunctioning and the development of post-stroke cognitive impairment in the chronic phase.

Estimation of visceral fat is useful for the diagnosis of significant fibrosis in patients with non-alcoholic fatty liver disease.

BACKGROUND: Obesity is a risk factor for non-alcoholic fatty liver disease (NAFLD), although obese patients with NAFLD do not always develop significant fibrosis. The distribution of body fat could predict the risk of NAFLD progression. AIM: To investigate the role of bioelectrical impedance-estimated visceral fat (VF) in assessing NAFLD severity. METHODS: In this cross-sectional study, patients with biopsy-proven NAFLD were prospectively included. All patients underwent anthropometric evaluation, blood tests and bioelectrical impedance analysis. RESULTS: Between 2017 and 2020, 119 patients were included [66.4% male, 56 years (SD 10.7), 62.2% obese, 61.3% with metabolic syndrome]. Sixty of them (50.4%) showed significant fibrosis (≥ F2) in liver biopsy. Age, VF and metabolic syndrome were associated with significant fibrosis (61 years vs 52 years, 16.4 vs 13.1, 73.3% vs 49.2%, respectively; P < 0.001 for all). In the multivariate analysis, VF and age were independently associated with significant fibrosis (VF, OR: 1.11, 95%CI: 1.02-1.22, P = 0.02; age, OR: 1.08, 95%CI: 1.03-1.12, P < 0.01). A model including these variables showed and area under the receiver operating characteristic curve (AUROC) of 0.75, which was not inferior to transient elastography or NAFLD fibrosis score AUROCs. We developed a nomogram including age and VF for assessing significant fibrosis in routine practice. CONCLUSION: VF is a surrogate marker of liver fibrosis in patients with NAFLD. Bioelectrical impedance analysis is an inexpensive and simple method that can be combined with age to guide patient referral when other resources may be unavailable.

HIF1α Suppresses Tumor Cell Proliferation through Inhibition of Aspartate Biosynthesis.

Cellular aspartate drives cancer cell proliferation, but signaling pathways that rewire aspartate biosynthesis to control cell growth remain largely unknown. Hypoxia-inducible factor-1α (HIF1α) can suppress tumor cell proliferation. Here, we discovered that HIF1α acts as a direct repressor of aspartate biosynthesis involving the suppression of several key aspartate-producing proteins, including cytosolic glutamic-oxaloacetic transaminase-1 (GOT1) and mitochondrial GOT2. Accordingly, HIF1α suppresses aspartate production from both glutamine oxidation as well as the glutamine reductive pathway. Strikingly, the addition of aspartate to the culture medium is sufficient to relieve HIF1α-dependent repression of tumor cell proliferation. Furthermore, these key aspartate-producing players are specifically repressed in VHL-deficient human renal carcinomas, a paradigmatic tumor type in which HIF1α acts as a tumor suppressor, highlighting the in vivo relevance of these findings. In conclusion, we show that HIF1α inhibits cytosolic and mitochondrial aspartate biosynthesis and that this mechanism is the molecular basis for HIF1α tumor suppressor activity.

Tenofovir vs lamivudine plus adefovir in chronic hepatitis B: TENOSIMP-B study.

AIM: To demonstrate the non-inferiority (15% non-inferiority limit) of monotherapy with tenofovir disoproxil fumarate (TDF) vs the combination of lamivudine (LAM) plus adefovir dipivoxil (ADV) in the maintenance of virologic response in patients with chronic hepatitis B (CHB) and prior failure with LAM. METHODS: This study was a Phase IV prospective, randomized, open, controlled study with 2 parallel groups (TDF and LAM+ADV) of adult patients with hepatitis B e antigen (HBeAg)-negative CHB, prior failure with LAM, on treatment with LAM+ADV for at least 6 mo, without prior resistance to ADV and with an undetectable viral load at the start of the study, in 14 Spanish hospitals. The follow-up time for each patient was 48 wk after randomization, with quarterly visits in which the viral load, biochemical and serological parameters, adverse effects, adherence to treatment and consumption of hospital resources were analysed. RESULTS: Forty-six patients were evaluated [median age: 55.4 years (30.2-75.2); 84.8% male], including 22 patients with TDF and 24 with LAM+ADV. During study development, hepatitis B virus DNA (HBV-DNA) remained undetectable, all patients remained HBeAg negative, and hepatitis B surface antigen (HBsAg) positive. Alanine aminotransferase (ALT) values at the end of the study were similar in the 2 groups (25.1 ± 7.65, TDF vs 24.22 ± 8.38, LAM+ADV, P = 0.646). No significant changes were observed in creatinine or serum phosphorus values in either group. No significant differences between the 2 groups were noted in the identification of adverse effects (AEs) (53.8%, TDF vs 37.5%, LAM+ADV, P = 0.170), and none of the AEs which occurred were serious. Treatment adherence was 95.5% and 83.3% in the TDF and the LAM+ADV groups, respectively (P = 0.488). The costs associated with hospital resource consumption were significantly lower with the TDF treatment than the LAM+ADV treatment (€4943 ± 1059 vs €5811 ± 1538, respectively, P < 0.001). CONCLUSION: TDF monotherapy proved to be safe and not inferior to the LAM+ADV combination therapy in maintaining virologic response in patients with CHB and previous LAM failure. In addition, the use of TDF generated a significant savings in hospital costs.

Cardiovascular morbidity and mortality after liver transplantation: The protective role of mycophenolate mofetil.

Cardiovascular (CV) diseases are recognized longterm causes of death after liver transplantation (LT). The objective of this multicenter study was to analyze the prevalence and the evolution of CV risk factors and CV morbidity and mortality in 1819 LT recipients along 5 years after LT. The influence of baseline variables on survival, morbidity, and mortality was studied. There was a continuous and significant increase of the prevalence of all the CV risk factors (except smoking) after LT. CV diseases were the fourth cause of mortality in the 5 years after LT, causing 12% of deaths during the follow-up. Most CV events (39%) occurred in the first year after LT. Preexisting CV risk factors such as age, pre-LT CV events, diabetes, metabolic syndrome, and hyperuricemia, and mycophenolate-free immunosuppressive therapy, increased post-LT CV morbidity and mortality. The development of new-onset CV risk factors after LT, such as dyslipidemia and obesity, independently affected late CV morbidity and mortality. Tacrolimus and steroids increased the risk of posttransplant diabetes, whereas cyclosporine increased the risk of arterial hypertension, dyslipidemia, and metabolic syndrome. In conclusion, CV complications and CV mortality are frequent in LT recipients. Preexisting CV risk factors, immunosuppressive drugs, but also the early new onset of obesity and dyslipidemia after LT play an important role on late CV complications. A strict metabolic control in the immediate post-LT period is advisable for improving CV risk of LT recipients. Liver Transplantation 23 498-509 2017 AASLD.

Altered Underlying Renal Tubular Function in Patients With Chronic Hepatitis B Receiving Nucleos(t)ide Analogs in a Real-World Setting: The MENTE Study.

BACKGROUND: Cases of renal tubular dysfunction have been reported in patients with hepatitis B and in patients with human immunodeficiency virus who are undergoing tenofovir treatment. However, little is known about the impact on tubular function in patients with chronic hepatitis B (CHB) under long-term use of entecavir (ETV) and tenofovir disoproxil fumarate (TDF). We evaluated markers of renal tubular function and bone turnover in patients with CHB treated with ETV or TDF. PATIENTS AND METHODS: A multicenter, cross-sectional study was performed on markers of renal tubular function and bone turnover in hepatitis B virus-monoinfected patients on long-term treatment with Entecavir or Tenofovir (the MENTE study). The analyzed parameters were: retinol-binding protein/creatinine, neutrophil gelatinase-associated lipocalin/creatinine, excretion of phosphates, uric acid excretion, glomerular filtrate, protein/creatinine, albumin/creatinine, serum creatinine, phosphate, CTX, P1NP, vitamin D, and parathormone. RESULTS: A total of 280 patients (ETV: 89, TDF: 69, control: 122) were included in this study. The TDF group was associated with altered levels of retinol-binding protein (RBP)/creatinine (TDF 25% vs. 7% ETV and control; P<0.001). Protein/creatinine, uric acid excretion, P1NP1, and parathormone were higher in the TDF group. The proportion of patients with serum phosphate <2.5 mg/dL was higher in both the ETV and the TDF groups compared with the control. The multivariate analysis showed that the use of TDF was independently associated with a higher risk of altered excretion of RBP/creatinine (4.4; interquartile range: 1.4 to 14; P=0.013). CONCLUSIONS: We found an independent association between TDF use and altered RBP excretion. This finding indicates subclinical tubular damage. Because tubular dysfunction can precede the decline of renal function, close monitoring of RBP levels in patients with CHB on nucleos(t)ide analog treatment must be performed for early detection of TDF-related renal toxicity. In this study, these differences in tubular function were not associated with concomitant changes in markers of bone turnover.

Control of blood pressure in liver transplant recipients.

BACKGROUND: Increased blood pressure (BP) is common after liver transplantation. However, there is scarce information on its control. METHODS: In this prospective, cross-sectional, multicenter study, we determined BP according to the recommended international standards in 921 liver transplant patients during one routine outpatient visit to assess their grade of control of BP. At the time of the study, 490 patients had been previously diagnosed with arterial hypertension and were receiving antihypertensive treatment, and 431 were not previously diagnosed as hypertensive. RESULTS: In the hypertensive group, arterial hypertension was uncontrolled (BP >140/90 mm Hg [>130/80 in diabetics]) in 158 (32%) patients and controlled in 332 (68%) patients. In a multivariate analysis, only diabetes was identified as a significant predictor of uncontrolled hypertension. Among patients not previously diagnosed as hypertensive, BP was increased in 106 (25%) and normal in 325 (75%). On multivariate analysis, the only variable independently associated with increased BP in this group was metabolic syndrome. CONCLUSION: BP is not adequately controlled in a noticeable percentage of liver transplant patients, especially in subjects with diabetes or metabolic syndrome.

[Virological response to adefovir dipivoxil predicts the long-term development of resistance in previously untreated patients with HBeAg-negative chronic hepatitis B]. / La respuesta virológica al tratamiento con adefovir dipivoxil predice el desarrollo de resistencias a largo plazo en pacientes con hepatitis crónica B HBeAg negativo previamente no tratados.

BACKGROUND AND OBJECTIVE: Adefovir dipivoxil monotherapy in lamivudine-resistant patients is associated with more frequent development of resistance than in naïve patients. The virological response during treatment predicts the risk of developing resistance. The aims of this study were to assess the efficacy of adefovir dipivoxil treatment in naïve and lamivudine-resistant patients and to determine whether virological response predicts the development of adefovir resistance. PATIENTS AND METHOD: This study included 82 patients with HBeAg-negative chronic hepatitis B (CHB) who received adefovir dipivoxil therapy. During active treatment, HBV-DNA values were determined by polymerase chain reaction; in addition, the presence of adefovir resistance-associated mutations was studied in cases of virological breakthrough. RESULTS: Virological response at 12 and 24 months was 59% and 73% in naive patients compared with 40% and 67% in lamivudine-resistant patients, whereas virological breakthrough at 24 months was 9.5% in naïve patients compared with 20% in lamivudine-resistant patients. A small percentage (4%) of patients with virological response at 12 months showed virological breakthrough between 12 and 40 months versus 29.4% of patients without virological response (P=.03). In lamivudine-resistant patients, virological response at 12 months was not a predictive factor for the development of virological breakthrough. CONCLUSIONS: Adefovir dipivoxil monotherapy in lamivudine-resistant patients is associated with an increased tendency to develop virological breakthrough, which cannot be predicted by virological response at 12 months of treatment. In naive patients, an undetectable viral load at 12 months of treatment ensures the absence of virological breakthrough at 40 months of treatment.

La respuesta virológica al tratamiento con adefovir dipivoxil predice el desarrollo de resistencias a largo plazo en pacientes con hepatitis crónica B HBeAg negativo previamente no tratados / Virological response to adefovir dipivoxil predicts the long-term development of resistance in previously untreated patients with HBeAg-negative chronic hepatitis B

Fundamento y objetivo La monoterapia con adefovir dipivoxil en pacientes resistentes a lamivudina se asocia con mayor desarrollo de resistencias que en naive. La respuesta virológica durante el tratamiento predice el riesgo de resistencias. Los objetivos de este estudio son evaluar la eficacia del tratamiento con adefovir dipivoxil en pacientes naive y resistentes a lamivudina y valorar si la respuesta virológica predice el desarrollo de resistencias a adefovir. Pacientes y metodo Se ha incluido a 82 pacientes con hepatitis crónica B (HCB) HBeAg negativo tratados con adefovir dipivoxil. Durante el tratamiento se determinó ADNVHB por reacción en cadena de la polimerasa y en los casos de breakthrough virológico, se estudió la presencia de mutaciones asociadas a resistencia a adefovir. Resultados La respuesta virológica a los 12 y 24 meses fue del 59 y el 73% en naive y del 40 y el 67% en resistentes a lamivudina. El breakthrough virológico a los 24 meses fue del 9,5% en naive y el 20% en resistentes a lamivudina. El 4% de los naive con respuesta virológica a los 12 meses presentó breakthrough virológico entre 12 y 40 meses de tratamiento frente al 29,4% de los pacientes sin respuesta virológica (p=0,03). En resistentes a lamivudina la respuesta virológica a los 12 meses no predijo el breakthrough virológico. Conclusiones La monoterapia con adefovir dipivoxil en pacientes resistentes a lamivudina se asocia con mayor tendencia al desarrollo de breakthrough virológico no predecible por la respuesta virológica a los 12 meses de tratamiento. En pacientes naive la carga viral no detectable a los 12 meses de tratamiento predice la ausencia de breakthrough virológico hasta los 40 meses de tratamiento (AU)

Background and objective Adefovir dipivoxil monotherapy in lamivudine-resistant patients is associated with more frequent development of resistance than in naïve patients. The virological response during treatment predicts the risk of developing resistance. The aims of this study were to assess the efficacy of adefovir dipivoxil treatment in naïve and lamivudine-resistant patients and to determine whether virological response predicts the development of adefovir resistance. Patients and method This study included 82 patients with HBeAg-negative chronic hepatitis B (CHB) who received adefovir dipivoxil therapy. During active treatment, HBV-DNA values were determined by polymerase chain reaction; in addition, the presence of adefovir resistance-associated mutations was studied in cases of virological breakthrough. Results Virological response at 12 and 24 months was 59% and 73% in naive patients compared with 40% and 67% in lamivudine-resistant patients, whereas virological breakthrough at 24 months was 9.5% in naïve patients compared with 20% in lamivudine-resistant patients. A small percentage (4%) of patients with virological response at 12 months showed virological breakthrough between 12 and 40 months versus 29.4% of patients without virological response (P=.03). In lamivudine-resistant patients, virological response at 12 months was not a predictive factor for the development of virological breakthrough. Conclusions Adefovir dipivoxil monotherapy in lamivudine-resistant patients is associated with an increased tendency to develop virological breakthrough, which cannot be predicted by virological response at 12 months of treatment. In naive patients, an undetectable viral load at 12 months of treatment ensures the absence of virological breakthrough at 40 months of treatment (AU)

Cytoprotective properties of alpha-tocopherol are related to gene regulation in cultured D-galactosamine-treated human hepatocytes.

Vitamin E (alpha-tocopherol) has demonstrated antioxidant activity and gene-regulatory properties. d-Galactosamine (D-GalN)-induced cell death is mediated by nitric oxide in hepatocytes, and it is associated with hepatic steatosis. The beneficial properties of alpha-tocopherol and their relation to oxidative stress and gene regulation were assessed in D-GalN-induced cell death. Hepatocytes were isolated from human liver resections by a collagenase perfusion technique. alpha-Tocopherol (50 microM) was administered at the advanced stages (10 h) of D-GalN-induced cell death in cultured hepatocytes. Cell death, oxidative stress, alpha-tocopherol metabolism, and NF-kappaB-, pregnane X receptor (PXR)-, and peroxisome proliferator-activated receptor (PPAR-alpha)-associated gene regulation were estimated in the hepatocytes. D-GalN increased cell death and alpha-tocopherol metabolism. alpha-Tocopherol exerted a moderate beneficial effect against apoptosis and necrosis induced by D-GalN. Induction (rifampicin) or inhibition (ketoconazole) of alpha-tocopherol metabolism and overexpression of PXR showed that the increase in PXR-related CYP3A4 expression caused by alpha-tocopherol enhanced cell death in hepatocytes. Nevertheless, the reduction in NF-kappaB activation and inducible nitric oxide synthase expression and the enhancement of PPAR-alpha and carnitine palmitoyl transferase gene expression by alpha-tocopherol may be relevant for cell survival. In conclusion, the cytoprotective properties of alpha-tocopherol are mostly related to gene regulation rather than to antioxidant activity in toxin-induced cell death in hepatocytes.

S-Nitrosation of proteins during D-galactosamine-induced cell death in human hepatocytes.

Nitric oxide (NO) participates in the cell death induced by d-Galactosamine (d-GalN) in hepatocytes, and NO-derived reactive oxygen intermediates are critical contributors to protein modification and hepatocellular injury. It is anticipated that S-nitrosation of proteins will participate in the mechanisms leading to cell death in d-GalN-treated human hepatocytes. In the present study, d-GalN-induced cell death was related to augmented levels of NO production and S-nitrosothiol (SNO) content. The biotin switch assay confirmed that d-GalN increased the levels of S-nitrosated proteins in human hepatocytes. S-nitrosocysteine (CSNO) enhanced protein S-nitrosation and altered cell death parameters that were related to S-nitrosation of the executioner caspase-3. Fifteen S-nitrosated proteins participating in metabolism, antioxidative defense and cellular homeostasis were identified in human hepatocytes treated with CSNO. Among them, seven were also identified in d-GalN-treated hepatocytes. The results here reported underline the importance of the alteration of SNO homeostasis during d-GalN-induced cell death in human hepatocytes.

Adverse hepatic reactions associated with calcium carbimide and disulfiram therapy: is there still a role for these drugs?

Disulfiram and calcium carbimide are two alcohol deterrants widely used in alcoholism treatment, however, there exist great concerns over their safety. Reports on hepatotoxicity, mainly related to disulfiram therapy, have been published. The hepatotoxic potential of calcium carbimide is less well characterized. Here, we describe four cases of liver damage related to this therapeutic group that were submitted to a Registry of hepatotoxicity and point out the limitations that we face when prescribing these compounds. A reassessment of the role of these compounds in the management of alcohol dependence is clearly needed.

Dual effect of ethanol on cell death in primary culture of human and rat hepatocytes.

AIMS: In-vivo and in-vitro studies have shown that ethanol induces hepatocyte damage. The aim of the present study was to evaluate the effect of a broad range of ethanol concentrations on apoptosis and necrosis in primary culture of human and rat hepatocytes. METHODS: Human and rat hepatocytes were isolated from human hepatectomies and male Wistar rats (200-250 g) using the classical collagenase perfusion method. After stabilization of cell culture, ethanol (0-10 mmol/l) was administered and the parameters were measured 24 h after ethanol addition. Apoptosis was studied by DNA fragmentation, iodide propidium-DNA staining, caspase-3 activity and annexin V binding in hepatocytes. Necrosis was evaluated by lactate dehydrogenase (LDH) release. Malondialdehyde (MDA) and GSH/GSSG were used as parameters of oxidative stress. RESULTS: Ethanol enhanced dose-dependently all the parameters associated with apoptosis in human and rat hepatocytes. Low or high ethanol concentrations induced an opposite action against cell necrosis in cultured hepatocytes. Low concentrations of ethanol (1-2 mmol/l) reduced LDH release from human and rat hepatocytes. However, the highest ethanol concentration (10 mmol/l) induced a sharp increase in cell necrosis. The effect of ethanol on cell necrosis was related to lipid peroxidation in hepatocytes. CONCLUSIONS: Ethanol differentially regulates apoptosis or necrosis in cultured hepatocytes. Although ethanol exerted a dose-dependent induction of apoptosis, low ethanol concentrations were able to reduce basal lipid peroxidation and necrosis in hepatocytes. The highest ethanol concentration (10 mmol/l) induced apoptosis and necrosis in human and rat cultured hepatocytes.