Search

A protective effect of Rho-kinase inhibitor on various organ injuries is gaining attention. Regarding liver injury, Rho-kinase inhibitor is reported to prevent carbon tetrachloride (CCl4)- or dimethylnitrosamine-induced liver fibrosis and hepatic ischemia-reperfusion injury in rats. Because Rho-kinase inhibitor not only improved liver fibrosis but also reduced serum alanine aminotransferase (ALT) level in CCl4-induced liver fibrosis, we wondered whether Rho-kinase inhibitor might exert a direct hepatocyte-protective effect. We examined this possibility in acute CCl4 intoxication in rats. Rho-kinase inhibitor, HA-1077, reduced serum alanine ALT level in rats with acute liver injury induced by CCl4 with the improvement of histological damage and the reduction of the number of apoptotic cells. In cultured rat hepatocytes in serum-free condition, HA-1077 reduced apoptosis evaluated by quantitative determination of cytoplasmic histone-associated DNA oligonucleosome fragments with the reduction of caspase-3 activity and the enhancement of Bcl-2 expression. HA-1077 stimulated phosphorylation of Akt, and wortmannin, an inhibitor of phosphatidylinositol 3-kinase (PI3-kinase)/Akt pathway, abrogated the reduction of hepatocyte apoptosis by HA-1077 in vitro. Furthermore, wortmannin abrogated the reduction of serum ALT level by HA-1077 in rats with acute liver injury induced by CCl4, suggesting that the activation of PI3-kinase/Akt pathway may be involved in the hepatocyte-protective effect by Rho-kinase inhibitor in vivo. In conclusion, Rho-kinase inhibitor prevented hepatocyte damage in acute liver injury induced by CCl4 in rats and merits consideration as a hepatocyte-protective agent in liver injury, considering its direct antiapoptotic effect on hepatocytes in vitro.

Aims: Liver injury can occur during antiviral therapies with direct-acting antivirals (DAAs), potentially necessitating discontinuation of the therapies, with consequent worsening of the sustained viral response (SVR) rates, in patients with hepatitis C virus (HCV). To clarify the mechanisms involved in serum transaminase level elevation, we performed a retrospective evaluation of the serum concentrations of daclatasvir and asunaprevir, both classified as DAAs, in patients receiving treatment with a combination of the two drugs. Methods: Subjects were 278 Japanese patients with genotype-1b HCV who received daclatasvir plus asunaprevir therapy for more than 4 weeks. Serum concentrations of both the DAAs were measured at 4 weeks after the initiation of therapy. Result: Liver injuries including serum AST and/or ALT level elevation to 150 U/L or over were found in 34 patients (12.2%). Multivariate logistic regression analysis identified serum asunaprevir concentrations as being significantly associated with developing liver injury, with an odds ratio of 1.046 (95% confidence interval 1.011–1.082, p<0.05). Serum asunaprevir concentrations showed correlation with the extent of liver fibrosis, estimated by peripheral platelets counts and serum albumin levels and baseline and FIB4 index and serum Mac-2 binding protein glycosylation isomer (M2BPGi) levels at 4 weeks of the therapy; the concentrations were significantly higher among patients showing 3.0 or more of M2BPGi levels than among those with the levels less than 3.0; on the other hand, no such correlation/difference was found in serum daclatasvir concentrations. Conclusion: High serum concentrations of serum asunaprevir, which were associated with the extent of liver fibrosis, appear to provoke the occurrence of liver injury in patients with genotype-1b HCV receiving combined daclatasvir plus asunaprevir therapy. [ABSTRACT FROM AUTHOR]

Aim: To establish diagnostic criteria for acute‐on‐chronic liver failure (ACLF) in Japan, a multicenter pilot survey was carried out to examine the usefulness of overseas criteria in patients with chronic liver diseases manifesting acute decompensation. Methods: Patients fulfilling the Asian‐Pacific Association for the Study of the Liver (APASL), European Association for the Study of the Liver (EASL), or Chinese Medical Association (CMA) criteria for decompensation were enrolled from eight institutions in Japan, and the clinical features were evaluated. Results: Among 112 patients, 109 patients (97.3%) fulfilled the APASL criteria for decompensation; 7 patients were excluded because the decompensation had been provoked by gastrointestinal bleeding. Consequently, 102 patients (91.1%) were diagnosed as having ACLF according to the APASL definition. Among the patients who fulfilled the APASL criteria for decompensation, the etiologies of the underlying liver diseases were alcohol abuse in 59 cases (54.1%) and hepatitis B or hepatitis C virus infection in 24 (22.0%). The acute insults were alcohol abuse in 50 (45.9%), bacterial infection in 26 (23.9%), and exacerbation of underlying liver disease in 14 (12.8%). Fifty‐four patients (49.5%) satisfied the CMA criteria, but the survival rates were similar between patients who did and those who did not meet the criteria. When 84 patients with underlying cirrhosis were classified according to the EASL–Chronic Liver Failure (Clif) Consortium criteria, the survival rates differed according to grade: 67.6% (23/34) for patients without ACLF, and 41.2% (14/34) and 18.8% (3/16) for those with grade 1/2 and grade 3 ACLF, respectively. Conclusion: The APASL definition was suitable for screening Japanese patients with ACLF, including those whose conditions were triggered by gastrointestinal bleeding, and the EASL‐Clif Consortium criteria were useful for predicting outcome. [ABSTRACT FROM AUTHOR]

Liver regeneration is considered to be retarded or suppressed in patients with acute liver failure. However, the mechanisms for this suppression remain to be elucidated. In order to evaluate deficiencies in liver regeneration in patients with acute liver failure, we focused on the cross-communication of growth-associated factors in experimental models. In primary cultured rat hepatocytes, the levels of cellular p53 and transforming growth factor-alpha (TGF-alpha), as well as DNA synthesis increased by the addition of hepatocyte growth factor (HGF). When p53 activity was suppressed, TGF-alpha expression and DNA synthesis were reduced. DNA synthesis was also reduced when TGF-alpha activity was suppressed. In rats after partial hepatectomy, hepatic HGF and p53 protein levels increased, followed by an increase of hepatic TGF-alpha levels and hepatocyte proliferation. Circulating levels of HGF and TGF-alpha correlated with changes in the hepatic levels. The suppression of TGF-alpha activity reduced the proliferation of hepatocytes in these rats. In patients suffering from acute hepatitis, serum HGF levels increased followed by an increase of serum TGF-alpha levels. In contrast, in patients with acute liver failure, the increase of serum TGF-alpha levels was suppressed depending on the severity of hepatic failure, even though serum HGF levels markedly increased. The patients' hepatic levels were consistent with serum levels. Cross-communication of growth associated factors may be important in the progression of liver regeneration, and impaired regenerative capacity in patients with acute liver failure may be attributable, at least in part, to a disruption of communication of growth-associated factors. [ABSTRACT FROM AUTHOR]

The author comments on a study on the sex difference that exists in the prevalence of nonalcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH). He references various studies including one by Yumiko Anezaki et al in an issue of "Hepatology Research." In the study, female hepatocyte-specific Pten-knockout mice were reported to be less prone to the development of hepatic steatosis and inflammation compared to the male mice. The author also argues that sex difference in NAFLD and NASH animal models is highlighted but is complicated.

Brief periods of tissue ischemia produced tissue resistance to prolonged ischemia and reperfusion, a phenomenon called ischemic preconditioning. The mechanisms of ischemic preconditioning were examined in a rat warm ischemia–reperfusion model as well as the effect of ischemic preconditioning on liver regeneration. Ischemic preconditioning decreased liver injury after warm ischemia–reperfusion, which was reversed by Kupffer cell depletion. Ischemic preconditioning stimulated Kupffer cells to produce reactive oxygen species. Scavengers of reactive oxygen species reversed the effect of ischemic preconditioning, and pretreatment with sublethal dose of hydrogen peroxide mimicked ischemic preconditioning effect. Rat livers were preconditioned by ischemia and subjected to 70% partial hepatectomy. Liver regeneration was then evaluated serially. Ischemic preconditioning promoted liver regeneration, which was reversed by adenosine A2 receptor antagonism and mimicked by adenosine A2 receptor agonism. Promotion of liver regeneration by ischemic preconditioning and adenosine A2 receptor agonism were reversed by Kupffer cell depletion. In conclusion, ischemic preconditioning stimulates Kupffer cells to produce reactive oxygen species, leading to hepatocyte protection against warm ischemia–reperfusion injury; and ischemic preconditioning promoted liver regeneration via adenosine A2 receptor pathway in Kupffer cells. [ABSTRACT FROM AUTHOR]

Abstract: Background: The clinical significance of autotaxin (ATX), a key enzyme for the production of the bioactive lysophospholipid lysophosphatidic acid remains unknown. Serum ATX enzymatic activity reportedly increases in parallel with liver fibrosis and exhibits a gender difference. Methods: Serum ATX antigen level, measured easier than the activity, was evaluated as a marker of liver fibrosis in 2 cohorts of chronic liver disease caused by hepatitis C virus. Results: In the first cohort, serum ATX level correlated significantly with liver fibrosis stage and was the best parameter for prediction of cirrhosis with an area under the receiver operating characteristic curve (AUROC) of 0.756 in male and 0.760 in female, when compared with serum hyaluronic acid and aminotransferase-to-platelet ratio index, an established marker of liver fibrosis. In another cohort, serum ATX level correlated significantly with liver stiffness, a novel reliable marker of liver fibrosis, being the second-best parameter in male (AUROC, 0.799) and in female (AUROC, 0.876) for prediction of significant fibrosis, and the best parameter in male (AUROC, 0.863) and the third-best parameter in female (AUROC, 0.872) for prediction of cirrhosis, both of which were judged by liver stiffness. Conclusions: Serum ATX level may be a novel marker of liver fibrosis. [Copyright &y& Elsevier]