PGE2 induces apoptosis of hepatic stellate cells and attenuates liver fibrosis in mice by downregulating miR-23a-5p and miR-28a-5p.

MicroRNAs (miRNAs), small noncoding RNAs modulating messenger RNA (mRNA) and protein expression, have emerged as key regulatory molecules in chronic liver diseases, whose end stage is hepatic fibrosis, a major global health burden. Pharmacological strategies for prevention or treatment of hepatic fibrosis are still limited, what makes it necessary to establish a better understanding of the molecular mechanisms underlying its pathogenesis. In this context, we have recently shown that cyclooxygenase-2 (COX-2) expression in hepatocytes restricts activation of hepatic stellate cells (HSCs), a pivotal event in the initiation and progression of hepatic fibrosis. Here, we evaluated the role of COX-2 in the regulation of a specific set of miRNAs on a mouse model of CCl4 and bile duct ligation (BDL)-induced liver fibrosis. Our results provide evidence that COX-2 represses miR-23a-5p and miR-28-5p expression in HSC. The decrease of miR-23a-5p and miR-28-5p expression promotes protection against fibrosis by decreasing the levels of pro-fibrogenic markers α-SMA and COL1A1 and increasing apoptosis of HSC. Moreover, we demonstrate that serum levels of miR-28-5p are decreased in patients with chronic liver disease. These results suggest a protective effect exerted by COX-2-derived prostanoids in the process of hepatofibrogenesis.

Obesity-dependent metabolic signatures associated with nonalcoholic fatty liver disease progression.

Our understanding of the mechanisms by which nonalcoholic fatty liver disease (NAFLD) progresses from simple steatosis to steatohepatitis (NASH) is still very limited. Despite the growing number of studies linking the disease with altered serum metabolite levels, an obstacle to the development of metabolome-based NAFLD predictors has been the lack of large cohort data from biopsy-proven patients matched for key metabolic features such as obesity. We studied 467 biopsied individuals with normal liver histology (n=90) or diagnosed with NAFLD (steatosis, n=246; NASH, n=131), randomly divided into estimation (80% of all patients) and validation (20% of all patients) groups. Qualitative determinations of 540 serum metabolite variables were performed using ultraperformance liquid chromatography coupled to mass spectrometry (UPLC-MS). The metabolic profile was dependent on patient body-mass index (BMI), suggesting that the NAFLD pathogenesis mechanism may be quite different depending on an individual's level of obesity. A BMI-stratified multivariate model based on the NAFLD serum metabolic profile was used to separate patients with and without NASH. The area under the receiver operating characteristic curve was 0.87 in the estimation and 0.85 in the validation group. The cutoff (0.54) corresponding to maximum average diagnostic accuracy (0.82) predicted NASH with a sensitivity of 0.71 and a specificity of 0.92 (negative/positive predictive values=0.82/0.84). The present data, indicating that a BMI-dependent serum metabolic profile may be able to reliably distinguish NASH from steatosis patients, have significant implications for the development of NASH biomarkers and potential novel targets for therapeutic intervention.

Induction of tumor necrosis factor alpha production by human hepatocytes in chronic viral hepatitis.

Tumor necrosis factor alpha (TNF-alpha) is a multifunctional cytokine that has an important role in the pathogenesis of inflammation, cachexia, and septic shock. Although TNF-alpha is mainly produced by macrophages, there is evidence regarding TNF-alpha production by cells that are not derived from bone marrow. TNF-alpha production by normal and inflamed human liver was assessed at both mRNA and protein levels. Using a wide panel of novel anti-TNF-alpha monoclonal antibodies and a specific polyclonal antiserum, TNF-alpha immunoreactivity was found in hepatocytes from patients chronically infected with either hepatitis B virus (HBV) or hepatitis C virus. Minimal TNF-alpha immunoreactivity was detected in the mononuclear cell infiltrate and Kupffer cells. In situ hybridization experiments using a TNF-alpha RNA probe showed a significant expression of TNF-alpha mRNA in hepatocytes, Kupffer cells, and some infiltrating mononuclear cells. By contrast, TNF-alpha was detected at low levels in liver biopsies from normal individuals or patients with alcoholic liver disease and low expression of TNF-alpha mRNA was observed in these specimens. Transfection of HepG2 hepatoblastoma cells with either HBV genome or HBV X gene resulted in induction of TNF-alpha expression. Our results demonstrate that viral infection induces, both in vivo and in vitro, TNF-alpha production in hepatocytes, and indicate that the HBV X protein may regulate the expression of this cytokine. These findings suggest that TNF-alpha may have an important role in human liver diseases induced by viruses.

Inducible nitric oxide synthase expression in chronic viral hepatitis. Evidence for a virus-induced gene upregulation.

Increased nitric oxide (NO) production may contribute to the pathological changes featuring in some inflammatory diseases, but the role of NO in chronic viral hepatitis is still unknown. We compared the inducible NO synthase (NOS2) expression in the liver of patients with chronic viral hepatitis with that of both nonviral liver disease and histologically normal liver. NOS2 expression was assessed by immunohistochemical and in situ hybridization studies of liver biopsy sections. An intense hepatocellular NOS2 reactivity was detected in chronic viral hepatitis, whereas it was weakly or not observed in nonviral liver disease or normal liver, respectively. In addition, we determined whether the hepatitis B virus (HBV) might regulate the synthesis of this enzyme. NOS2 mRNA and protein levels as well as enzyme activity were assessed in cytokine-stimulated HBV-transfected and untransfected hepatoma cells. Transfection with either HBV genome or HBV X gene resulted in induction of NOS2 mRNA expression, and the maximal induction of this transcript and NO production was observed in cytokine-stimulated HBV-transfected cells. These results indicate that hepatotropic viral infections are able to upregulate the NOS2 gene expression in human hepatocytes, suggesting that NO may mediate important pathogenic events in the course of chronic viral hepatitis.

Soluble adhesion molecules correlate with liver inflammation and fibrosis in chronic hepatitis C treated with interferon-alpha.

BACKGROUND: In chronic hepatitis C the relation of circulating adhesion molecules to disease features before, during and after therapy has not been completely established. AIM: To analyse the basal levels of circulating adhesins and the changes induced by interferon in these patients. METHODS: We studied, using ELISA assays, the serum levels of soluble intercellular adhesion molecule-1 (sICAM-1) and vascular cell adhesion molecule-1 (sVCAM-1) in 52 patients with chronic hepatitis C on entry, prior to finalizing a 6-month course of interferon-alpha therapy and at the end of the follow-up. Correlations with clinical, virological and histological features, including inflammation and fibrosis, were calculated by Pearson's r-test. RESULTS: Liver necroinflammation was more closely related to sICAM-1 (r = 0.54, P = 0.0000) than to sVCAM-1 (r = 0.32, P = 0.02). Fibrosis, both as serum pIIIP and histological scoring, was, however, clearly related to sVCAM-1 (1071+/-291 in patients who scored 0-2 vs. 1870+/-458 in patients who scored 3-4; P = 0.0000). Severe fibrosis was never found below a sVCAM-1 cut-off threshold of 1300 ng/mL. Levels of both adhesins did not correlate with viraemia and were comparable among 1b and non-1b genotypes. Sustained response to interferon was significantly related to low viraemia (P = 0.03), non-lb type (P = 0.04) and low sICAM-1 (P = 0.04), but not to sVCAM-1. On finalizing therapy, patients with normal transaminases had reduced sICAM-1 (P = 0.0005), but not sVCAM-1 levels. CONCLUSIONS: In chronic hepatitis C, sICAM-1 was a marker of liver necroinflammation while sVCAM-1 reflected fibrosis. Both low sVCAM-1 and pIIIP serum concentrations were strictly linked, suggesting that measuring sVCAM-1 could give information on the degree of liver fibroplasia.

Increased circulating and intrahepatic T-cell-specific chemokines in chronic hepatitis C: relationship with the type of virological response to peginterferon plus ribavirin combination therapy.

AIMS: To determine the serum and intrahepatic levels of T-helper-1-associated chemokines in patients with chronic hepatitis C before, during and after peginterferon plus ribavirin combination therapy and to search for correlations with baseline characteristics of hepatitis C virus-related chronic liver disease and type of therapeutic response. METHODS: Serum chemokine levels were determined by enzyme-linked immunosorbent assays and intrahepatic chemokine messenger RNA and protein levels were tested by ribonuclease protection assay and immunohistochemistry. RESULTS: Serum and intrahepatic chemokine levels were elevated in all patients with chronic hepatitis C and showed a marked decrease in patients who obtained a virological response vs. non-responders. Increased serum interferon-gamma-inducible protein-10 levels at baseline in genotype 1-infected patients were significantly associated with greater degrees of intrahepatic inflammation and fibrosis (P = 0.0046 and P = 0.02, respectively) and with virological non-response (P = 0.01). In patients with genotype 1, basal serum interferon-gamma-inducible protein-10 levels greater than 299 pg/mL identified 80% of non-responders and lower than 299 pg/mL identified 63% of responders. CONCLUSIONS: Circulating and intrahepatic T-helper-1-associated chemokines are abnormally elevated in patients with chronic hepatitis C. Increased baseline serum interferon-gamma-inducible protein-10 levels in genotype 1-infected patients are associated with virological non-response to peginterferon plus ribavirin combination therapy.

Interferon alpha with ribavirin for the treatment of chronic hepatitis C in non-responders or relapsers to interferon monotherapy.

BACKGROUND: A more effective therapy for chronic hepatitis C virus-infected patients is needed. AIM: To evaluate the efficacy, tolerance and timing of response to interferon alpha plus ribavirin in 60 patients with no response or reactivation after interferon alpha alone. METHODS: Sixty patients, 42 non-responders and 18 relapsers, received 3 million units three times weekly of interferon alpha-2b plus 1-1.2 g ribavirin daily, for 6 months. Basal biochemical and virological (HCV RNA and genotype) parameters were determined. Clinical examination, recording adverse effects, and laboratory tests, including viraemia, were carried out at 1, 2, 3 and 6 months. RESULTS: A significant (P < 0.001) progressive decrease of HCV RNA and alanine transaminase (ALT) levels was observed during treatment. On finalizing the sixth month, 42 patients (70%) had normal ALT and 26 (43.3%) were HCV RNA negative. Of these 26 complete responders, in 20 the viraemia was undetectable by the third month, while a late clearance at the sixth month of treatment was observed in six patients. Response rates were higher in previous responders to interferon alone (P < 0.05). Mild adverse effects appeared in 46 patients (79.6%), but only three were withdrawn due to serious side-effects. Significantly (P < 0.001), haemoglobin and leucocytes decreased, and bilirubin, ferritin and uric acid increased in the first month of treatment, with no changes thereafter. CONCLUSIONS: Interferon alpha plus ribavirin progressively decreased HCV RNA and ALT levels, achieving a complete response in the six months of treatment in 26 (43.3%) patients. This combined therapy was well tolerated.

Interferon alfa-2b plus ribavirin for chronic hepatitis C patients who have not responded to interferon monotherapy.

BACKGROUND: The role of combination therapy is poorly defined in chronic hepatitis C patients who are non-responders to interferon. AIM: To assess the efficacy, safety and tolerance of interferon alfa-2b plus ribavirin in chronic hepatitis C patients who do not respond to interferon monotherapy. METHODS: A total of 127 non-responder patients with chronic hepatitis C received 3 mU t.i.w. of interferon alfa-2b plus 1000-1200 mg ribavirin daily for 48 weeks. Effects of therapy were evaluated by serum aminotransferases and hepatitis C virus (HCV) RNA levels. RESULTS: Twenty-nine (23%) patients had an end-of-treatment response. Six months after treatment, 20 (16%) patients were sustained responders. Early loss of HCV RNA was the strongest predictor of a sustained response (P < 0.0001). Remission was also more frequent in patients with genotype 1b (P < 0.02), elevated alanine aminotransferase (P < 0.03) and low gamma glutamiltranspeptidase (P < 0.002). Treatment was discontinued in 21 (17%) patients: in 14 for intolerance and in seven due to side-effects. CONCLUSIONS: Combination therapy with interferon plus ribavirin produced a sustained response in 16% of chronic hepatitis C patients who were non-responders to interferon. This combination was safe and well tolerated.

Hepatitis C virus infection in Spanish volunteer blood donors: HCV RNA analysis and liver disease.

OBJECTIVE: To evaluate in a large group of volunteer blood donors the prevalence of antibodies to hepatitis C virus (anti-HCV) and the relation of transaminase (ALT) levels and viraemia to liver damage. DESIGN: A prospective study. SETTING: Transfusion Centre of the Autonomous Community of Madrid and the Liver Unit of the Princesa University Hospital. PATIENTS: From a population of 55,587 volunteer blood donors, 160 seropositive cases were further evaluated for virological and histological assessment. METHODS: Anti-HCV was tested by ELISA-2 and RIBA-2 assays. HCV RNA was analysed by nested PCR. Liver biopsies were obtained in 35 volunteer blood donors with abnormal ALT levels. RESULTS: The prevalence of anti-HCV detected by ELISA-2 was 0.93%. Serum ALT was abnormal in 61 of the 160 volunteers (38.1%). Of these, RIBA-2 was positive in 96.7% and HCV RNA was detectable in 96.1%. Serum ALT was normal in the remaining 99, 70.7% being RIBA-2 negative and 98.3% HCV RNA negative. The majority of biopsies (85.6%) showed chronic hepatitis. CONCLUSION: This study demonstrates that in blood donors screening for anti-HCV, a positive ELISA-2 test, when associated with abnormal ALT levels, is effective in recognizing subjects with active infection detected by HCV RNA and liver disease. Concerning ELISA-2 positive volunteer blood donors with normal ALT, long-term studies are warranted to elucidate whether they are really infected by HCV.

Hepatitis C virus infection detected by viral RNA analysis in porphyria cutanea tarda.

The high prevalence (62%) of anti-HCV in patients with porphyria cutanea tarda (PCT) found in a recent study prompted us to speculate that hepatitis C virus (HCV) infection could contribute to liver damage in this disease. The relationship between a positive serologic test and infectivity remains elusive, as anti-HCV false-positive reactivity has been described in some patients with chronic liver disease. Hence, it needs to be established if HCV infection plays a role in the pathogenesis of liver injury, or anti-HCV positivity may be an epiphenomenon in PCT patients. The aim of this study was to evaluate the existence of true HCV infection by verifying the presence of serum viral RNA in patients with PCT. HCV RNA was studied in sera from 36 patients with clinical and biochemical features of PCT using a polymerase chain reaction technique. Additionally, 26 patients with chronic alcoholic liver disease and 29 patients with different dermatological lesions but with no liver disease were studied as control groups. HCV RNA was positive in 29 of 36 patients (80.5%) with anti-HCV positive PCT. For alcoholic liver disease and dermatological disease controls the values for HCV RNA were 11.5% and 3.4%, respectively. HCV infection was found to be significantly higher in patients with PCT than in controls (P < 0.001), demonstrating that most subjects with clinically expressed PCT have true HCV infection. These data support the hypothesis that liver damage in some patients with PCT may be attributed to prolonged HCV infection, suggesting that treatment for chronic hepatitis C could be indicated.

Epidemiological risk factors and clinico-pathological presentation in chronic hepatitis C.

BACKGROUND/AIMS: To analyze the epidemiological risk factors related to clinical and pathological patterns on presentation in patients with chronic hepatitis C (CHC) without cirrhosis. METHODOLOGY: This prospective study, carried out in the Liver Unit of the Princesa University Hospital, includes a population of 253 patients with CHC without clinical features of cirrhosis evaluated for clinical, virological and histological assessment. A standardized questionnaire was used to identify the presence of risk factors for hepatitis C virus (HCV) infection. Anti-HCV was tested by ELISA-2 and RIBA-2 assays. HCV RNA was analyzed by nested PCR. Liver biopsies were obtained percutaneously or in some cases by laparoscopy. RESULTS: The mean age of patients was 43+/-15 years and 154 were males, being significantly younger than females (39+/-13 versus 50+/-14 years). A source of infection was ascertained in 204 (80.6%) patients and only 37 (14.6%) referred a history of acute hepatitis. Anti-HCV was ELISA-2 positive in all 253, and 133 were tested by RIBA-2 (131 positive, 1 negative, 1 indeterminate) and by nested PCR to detect HCV RNA, with positivity in all except 3, including both the RIBA-2 negative and indeterminate. No differences appeared in the histological activity index according to routes of infection, but in comparing sexes, females had a significantly higher total score as well as the inflammatory/hepatitic index and fibrosis. CONCLUSIONS: In CHC no epidemiological, clinical or biochemical patterns are indicative of pathological features. The more severe disease in females could be attributed to the fact that they were older and it could be assumed that viral infection progressed longer. This slow progression calls for a therapeutical option over many years.

Long-term effect of interferon alpha alone or after prednisone withdrawal in chronic hepatitis B. Interim report and review of the literature.

BACKGROUND/AIMS: This study analyzed the response of two selected groups of asymptomatic chronic hepatitis B patients, treated either with Interferon or with Prednisone plus the same regimen of Interferon, on finalizing treatment and after a long-term follow-up. PATIENTS AND METHODS: Twelve patients received Interferon over 6 months (group I) and 7 patients Prednisone plus Interferon with the same regimen (group II). Both groups were homogeneous in age, sexual preferences, serum ALT levels, liver histology and Knodell's index. Patients with decompensated liver disease, ongoing drug abuse, active alcoholism or viral superinfections were excluded. RESULTS: On finalizing treatment, no statistical differences were observed in either group, except for clearance of HBsAg, found to be better in group II. Both treatments improved hepatic histology. These results were comparable with those reported for both therapeutical regimens in the literature. After a mean follow-up period of 1.8 years for group I and 3.5 years for group II, no patient included in group II relapsed and 2 additionally cleared their replication markers; thus, a complete response was achieved in 6 (86%) out of 7 patients. In group I, however, 3 patients relapsed and 4 presented no change, obtaining a complete response in 3 (27%) out of 11 followed-up patients. When statistically studied, this improved response in the Prednisone plus Interferon group was significant in clearing HBV DNA, HBeAg and HBsAg and, also, in normalizing ALT levels. CONCLUSIONS: In spite of the few number of cases studied, these results could indicate an improved long-term evolution after a short course of steroids prior to Interferon in selected chronic hepatitis B patients.

Role of chemokines in the pathogenesis of liver diseases.

OBJECTIVE: while chemokines appear to be important in certain inflammatory disorders, little is known about the role of these proteins in chronic hepatitis C. MATERIAL AND METHODS: firstly, an extensive review of the expression pattern of chemokines in liver diseases with special emphasis in hepatitis C has been performed. Then, expression of selected CXC and CC chemokines and their receptors was assessed by immunohistochemistry and flow cytometry in a number of patients with chronic hepatitis C. RESULTS: evidence that certain CXC and CC chemokines are markedly expressed in chronic hepatitis C has been recently reported. In agreement with this, we have shown that the majority of liver-derived T lymphocytes from patients with chronic hepatitis C expressed CXCR3 and CCR5 chemokine receptors. In addition, an intense intrahepatic expression of their respective ligands, Mig and RANTES, was detected in the same patients studied. Furthermore, an association between the intrahepatic chemokine expression level and the inflammatory activity of chronic hepatitis C was found. CONCLUSIONS: all of these findings strongly suggest that intra hepatic chemokine signaling could play a key role regulating significant pathological events during chronic hepatitis C, opening new avenues for therapeutic interventions based on chemokines activities.

[Tissue expression of antigenic recognition and intercellular adhesion molecules in chronic viral hepatitis]. / Expresión tisular de moléculas de reconocimiento antigénico y de adhesión intercelular en la hepatitis crónica vírica.

OBJECTIVE: To analyze the expression of different HLA class I antigens and cell adhesion molecules on frozen liver sections from patients with chronic active hepatitis, types B and C. EXPERIMENTAL DESIGN: Liver biopsy samples were divided into two parts, one for routine histological examination and another, after snap-freezing and storing at -80 degrees C, for immunohistochemical analysis. To carry out immunoperoxidase and immunofluorescence stainings, a panel of monoclonal antibodies specific for HLA class I light (beta 2-microglobulin) and heavy chain determinants, and for adhesion molecules such as intercellular adhesion molecule-1 and lymphocyte function associate antigen-3 was used. PATIENTS: Immunohistochemistry was performed in frozen liver biopsy sections from 25 patients with viral chronic active hepatitis, 10 type B and 15 type C. As controls, normal liver samples and liver specimens from patients with cholestasis or steatosis were also studied. RESULTS: HLA class I light and heavy chain determinants were expressed on hepatocytes, biliary duct epithelium, sinusoidal lining cells and lymphocytes from patients and controls; however, the beta 2-microglobulin conformational epitope was undetectable on hepatocytes from normal livers or with cholestasis or steatosis, but clearly positive on hepatocytes from patients with hepatitis. In addition, in liver sections from controls no adhesion molecules positivity was detected on hepatocytes; by contrast, hepatocytes from patients with hepatitis showed markedly enhanced membranous reactivity for both adhesion molecules in areas of piecemeal and lobular necrosis. CONCLUSIONS: Virus B and C infections could induce an increased hepatocellular expression of HLA-class I determinants, including the conformational epitope adequate for antigen presentation, and cell-cell adhesion molecules. These findings underline the role of cell mediated immune reactions in the pathogenesis of hepatic injury in viral chronic hepatitis.

[Autoimmune hepatitis in patients with a diagnosis of multiple sclerosis]. / Hepatitis autoinmune en pacientes con diagnóstico de esclerosis múltiple.

Autoimmune hepatitis (AIH) is a chronic necroinflammatory liver disorder associated with hypergammaglobulinemia and circulating autoantibodies. Two patients previously diagnosed with multiple sclerosis who developed AIH are reported. One patient showed acute presentation with fulminant hepatic failure requiring liver transplantation. Serum autoantibodies were negative in both patients but a characteristic clinical course in the first patient as well as the hepatic histological features with typical pathological changes of AIH in both patients and a score compatible with AIH established the diagnosis.

Impaired autophagic flux is associated with increased endoplasmic reticulum stress during the development of NAFLD.

The pathogenic mechanisms underlying the progression of non-alcoholic fatty liver disease (NAFLD) are not fully understood. In this study, we aimed to assess the relationship between endoplasmic reticulum (ER) stress and autophagy in human and mouse hepatocytes during NAFLD. ER stress and autophagy markers were analyzed in livers from patients with biopsy-proven non-alcoholic steatosis (NAS) or non-alcoholic steatohepatitis (NASH) compared with livers from subjects with histologically normal liver, in livers from mice fed with chow diet (CHD) compared with mice fed with high fat diet (HFD) or methionine-choline-deficient (MCD) diet and in primary and Huh7 human hepatocytes loaded with palmitic acid (PA). In NASH patients, significant increases in hepatic messenger RNA levels of markers of ER stress (activating transcription factor 4 (ATF4), glucose-regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP)) and autophagy (BCN1) were found compared with NAS patients. Likewise, protein levels of GRP78, CHOP and p62/SQSTM1 (p62) autophagic substrate were significantly elevated in NASH compared with NAS patients. In livers from mice fed with HFD or MCD, ER stress-mediated signaling was parallel to the blockade of the autophagic flux assessed by increases in p62, microtubule-associated protein 2 light chain 3 (LC3-II)/LC3-I ratio and accumulation of autophagosomes compared with CHD fed mice. In Huh7 hepatic cells, treatment with PA for 8 h triggered activation of both unfolding protein response and the autophagic flux. Conversely, prolonged treatment with PA (24 h) induced ER stress and cell death together with a blockade of the autophagic flux. Under these conditions, cotreatment with rapamycin or CHOP silencing ameliorated these effects and decreased apoptosis. Our results demonstrated that the autophagic flux is impaired in the liver from both NAFLD patients and murine models of NAFLD, as well as in lipid-overloaded human hepatocytes, and it could be due to elevated ER stress leading to apoptosis. Consequently, therapies aimed to restore the autophagic flux might attenuate or prevent the progression of NAFLD.