Norihisa Nishimura

Reduction of endotoxin attenuates liver fibrosis through suppression of hepatic stellate cell activation and remission of intestinal permeability in a rat non-alcoholic steatohepatitis model

Previous clinical studies have demonstrated that endotoxin/toll-like receptor 4 (TLR4) signaling is critical in the inflammatory pathways associated with non-alcoholic steatohepatitis (NASH). In human and animal studies, NASH was associated with portal lipopolysaccharide (LPS) and the plasma LPS level was hypothesized to be associated with small intestinal bacterial overgrowth, change in composition of the microbiota and increased intestinal permeability. The aim of the present study was to investigate the roles of endogenous endotoxin and TLR4 in the pathogenesis of NASH. The effects of antibiotics were assessed in vivo using a choline deficiency amino acid (CDAA)-induced experimental liver fibrosis model. Antibiotics, including polymyxins and neomycins, were orally administered in drinking water. Antibiotics attenuated hepatic stellate cell (HSC) activation and liver fibrosis via TGF-β and collagen in an experimental hepatic fibrosis model. The mechanism by which antibiotics attenuated LPS-TLR4 signaling and liver fibrosis was assessed. Notably, TLR4 mRNA level in the liver was elevated in the CDAA group and the CDAA-induced increase was significantly reduced by antibiotics. However, no significant differences were observed in the intestine among all groups. Elevated mRNA levels of LPS binding protein, which was correlated with serum endotoxin levels, were recognized in the CDAA group and the CDAA-induced increase was significantly reduced by antibiotics. The intestinal permeability of the CDAA group was increased compared with the choline-supplemented amino acid group. The tight junction protein (TJP) in the intestine, determined by immunohistochemical analysis was inversely associated with intestinal permeability. Antibiotics improved the intestinal permeability and enhanced TJP expression. Inhibition of LPS-TLR4 signaling with antibiotics attenuated liver fibrosis development associated with NASH via the inhibition of HSC activation. These results indicated that reduction of LPS and restoration of intestinal TJP may be a novel therapeutic strategy for treatment of liver fibrosis development in NASH.

Predictive parameter of tolvaptan effectiveness in cirrhotic ascites

The efficacy of the vasopressin V2 receptor antagonist tolvaptan for difficult‐to‐treat cirrhotic ascites has recently been reported. However, its effect is variable among patients. This study aimed to clarify the predictive factors for obtaining a good response to tolvaptan in patients with difficult‐to‐treat ascites.

Combination of sorafenib and angiotensin-II receptor blocker attenuates preneoplastic lesion development in a non-diabetic rat model of steatohepatitis

BackgroundGiven the well-documented adverse side effects of sorafenib, many sorafenib-treated patients may need the reduced initial dose of the compound, and an alternative sorafenib-based therapy, which exerts similar clinical benefit, is anticipated. An angiostatic therapy with sorafenib is considered one of the promising approaches for chemoprevention of hepatocellular carcinoma. The aim of the current study was to elucidate the combination effect of low dose of sorafenib and angiotensin-II receptor blocker (ARB) on hepatocarcinogenesis, especially in conjunction with angiogenesis.MethodsThe chemopreventive effect on the development of liver preneoplastic lesions, angiogenesis, and several indices was elucidated in rats. We also performed several sets of in vitro experiments to examine the mechanisms involved.ResultsUsing a non-diabetic rat model of steatohepatitis with choline deficient l-amino acid-defined diet, sorafenib demonstrated marked inhibition of preneoplastic lesions in a dose dependent manner. Combined treatment with ARB (losartan) at a clinically comparable dose and half dose of sorafenib resulted in the inhibitory effect equivalent to that of common dose of sorafenib along with suppression of hepatic neovascularization and potent angiogenic factor, vascular endothelial growth factor. Furthermore, similar combined inhibitory outcomes were observed in several sets of in vitro studies.ConclusionSince the combinatorial treatment using low doses of sorafenib and ARB could sufficiently induce inhibitory effect on the development of preneoplastic lesions at the magnitude similar to the conventional dose of sorafenib, this regimen may provide new strategy for patients intolerant of the usual dose of sorafenib in the future.

Combination treatment of dipeptidyl peptidase IV inhibitor (sitagliptin) and angiotensin-II type 1 receptor blocker (losartan) suppresses progression in a nondiabetic rat model of steatohepatitis

Dipeptidyl peptidase‐4 (DPP4) inhibitors (DPP4‐I) are oral glucose‐lowering drugs for type 2 diabetes mellitus. Previously, we reported that DPP4‐I (sitagliptin) exerted suppressive effects on experimental liver fibrosis in rats. Blockade of the renin–angiotensin system by angiotensin‐II type 1 receptor blocker (losartan), commonly used in the management of hypertension, has been shown to significantly alleviate hepatic fibrogenesis and carcinogenesis. We aimed to elucidate the effects and possible mechanisms of a sitagliptin + losartan combination on the progression of non‐diabetic non‐alcoholic steatohepatitis (NASH) in a rat model.

Sodium glucose cotransporter 2 inhibitor canagliflozin attenuates liver cancer cell growth and angiogenic activity by inhibiting glucose uptake

Sodium‐glucose cotransporter 2 inhibitors (SGLT2‐Is) comprise a new class of antidiabetic agents that inhibit glucose reabsorption in the renal proximal tubules. Although a recent report demonstrated the potential ability of SGLT2‐Is to attenuate cancer growth of SGLT2‐expressing cancer cells, little is known about the effects of SGLT2‐Is on hepatocellular carcinoma (HCC). Here, we investigate the anti‐cancer properties of a SGLT2‐I, canagliflozin, against human liver cancer cells. SGTL2 mRNA and protein expression were detected in Huh7 and HepG2 cells, although not in HLE as well as primary human hepatocytes and hepatic stellate cells. Canagliflozin exerted antiproliferative effects on SGLT2‐expressing Huh7 and HepG2 cells in a dose‐dependent manner by inhibiting glycolytic metabolism including glucose uptake, lactate and intracellular ATP production. This agent also induced G2/M arrest and apoptosis with inhibited phosphorylation of ERK, p38 and AKT and cleavage of caspase3. Xenograft tumor growth assay showed that oral administration of canagliflozin (10 mg/kg/day) significantly reduced subcutaneous tumor burdens in a glycemic status‐independent manner, and attenuated intratumor vascularization in Huh7‐ and HepG2‐derived xenograft tumors in BALB/c nude mice. In vitro, canagliflozin suppressed the increased human umbilical vein endothelial cell (HUVEC) proliferation and tubular formation which were observed in Huh7 or HepG2 co‐cultures. By contrast, canagliflozin had no effect on tumor growth and intratumor angiogenesis in SGLT2‐null HLE‐derived xenograft models. These results indicate that SGLT2‐I therapy is a potential new strategy for the treatment of HCC.

Periostin cross‑reacts with the renin‑angiotensin system during liver fibrosis development

Periostin is a 90-kDa extracellular matrix protein, which is secreted primarily from fibroblasts and is expressed in the lungs, kidneys and heart valves. Angiotensin II (AT-II) serves pivotal roles in the pathogenesis of several diseases with accompanying fibrosis, including chronic liver diseases. AT-II induces periostin expression by regulating transforming growth factor-β1 (TGF-β1)/Smad signaling during cardiac fibrosis. The aim of the present study was to investigate the interaction between AT-II and periostin during liver fibrosis development. Fischer 344 rats were fed a choline-deficient L-amino-acid (CDAA)-defined diet for 12 weeks to simulate the development of steatohepatitis with liver fibrosis. Losartan, an AT-II type I receptor blocker, was administered to inhibit the effect of AT-II. The therapeutic effect of losartan on hepatic fibrosis development and on periostin expression was then evaluated. Several in vitro experiments were performed to examine the mechanisms underlying the interaction between AT-II and periostin in activated hepatic stellate cells (Ac-HSCs). Treatment with losartan suppressed the development of liver fibrosis induced by the CDAA diet, and reduced hepatic periostin expression. In addition, losartan treatment suppressed hepatic Ac-HSC expansion and hepatic TGF-β1 expression. In vitro analysis using LX2 HSC cells indicated that AT-II can augment TGF-β1 and collagen type I α1 mRNA expression via periostin expression, suggesting that the interaction between AT-II and periostin may serve a role in liver fibrosis development. In conclusion, blockade of AT-II-induced periostin may suppress the progression of liver fibrosis development.

Clinical significance of the Scheuer histological staging system for primary biliary cholangitis in Japanese patients.

Background Inadequate response to ursodeoxycholic acid (UDCA) is associated with unfavorable outcomes in patients with primary biliary cholangitis (PBC). We aimed to identify surrogate markers for predicting long-term prognosis and biochemical response to UDCA in patients with PBC. Patients and methods In this single-center, retrospective study, 99 patients with PBC were classified into responders (n=53) and nonresponders (n=46) based on reductions in the &ggr;-glutamyl transpeptidase levels at 1 year after initiating UDCA therapy (Nara criteria). We assessed whether the criteria for patentability by different countries are useful in predicting the prognosis of PBC. The accuracy of Scheuer and Nakanuma staging systems in predicting prognosis and treatment response was compared. Results Nara definition had comparable utility to the Paris-II definition for selecting patients in whom UDCA monotherapy can be safely continued. Patients at Scheuer stage 1 had a significantly better prognosis than those at Scheuer stages 3 or 4 (P<0.05 and 0.0001, respectively). Patients at Nakanuma stage 4 had decreased survival compared with those at stage 1 (P<0.05). The proportion of responders to nonresponders was significantly higher in stages 1–3 PBC than in stage 4 PBC, according to both staging systems (P<0.05 for both). All patients with Scheuer stage 4 PBC were nonresponders, whereas only 28.6% (2/7) of those with Nakanuma stage 4 PBC were responders. Conclusion The Scheuer staging system had greater utility in predicting long-term prognosis and UDCA response than the Nakanuma staging system.

Angiotensin receptor blockade attenuates cholangiocarcinoma cell growth by inhibiting the oncogenic activity of Yes-associated protein

Cholangiocarcinoma (CCA) is a destructive malignancy with limited responsiveness to conventional chemotherapy. Although angiotensin receptor blockers (ARBs) have gained attention for their potential anticancer activity, little is known about their effects on CCA. The transcriptional co-activator, Yes-associated protein (YAP) is a critical oncogene in several cancers, including CCA. Following recent evidence showing that YAP is regulated by angiotensin II (AT-II), we investigated the effects of an ARB, losartan, on two human CCA cell lines (KKU-M213 and HuCCT-1) with regards to YAP oncogenic regulation. Losartan suppressed AT-II-induced CCA cell proliferation in a dose-dependent manner, induced apoptosis, decreased YAP (Ser127), and downregulated the YAP target genes CTGF, CYR61, ANKRD1, and MFAP5. However, losartan did not affect epithelial-mesenchymal transition, differentiation, or stemness in the CCA cells. Xenograft tumor growth assay showed that oral administration of a low clinical dose of losartan considerably reduced subcutaneous tumor burden and attenuated intratumor vascularization in CCA cell-derived xenograft tumors in BALB/c nude mice. These results indicate that ARB therapy could serve as a potential novel strategy for CCA treatment.

Predisposing factors for hepatocellular carcinoma recurrence following initial remission after transcatheter arterial chemoembolization

Hepatocellular carcinoma (HCC) is prone to recurrence following curative treatment. The purpose of the present study was to identify the predisposing factors of HCC recurrence following complete remission achieved by transarterial chemoembolization (TACE). A retrospective cohort study of 70 consecutive patients with HCC who underwent TACE as the initial treatment was conducted. The patients were divided into two groups according to their 1-year disease-free survival (DFS) status; the early recurrence group (ER group; n=32), with HCC recurring within 1 year of initial TACE; and the non-early recurrence group (NER group; n=38), who did not experience recurrence within 1 year. The parameters identified as significantly associated with DFS time on univariate analysis were aspartate aminotransferase (AST), alanine aminotransferase and α-fetoprotein levels, as well as the tumor number (P=0.003, P=0.027, P=0.002 and P=0.005, respectively). Multivariate analysis revealed that AST levels and tumor number were significantly associated with a shorter DFS period (P=0.009 and P=0.038, respectively). The Mantel-Haenszel test revealed a significant trend of decreasing DFS with increasing tumor number. Among the patients with HCC in the ER group, locoregional recurrence occurred more frequently in those who received TACE alone compared with those treated with TACE combined with radiofrequency ablation treatment. In summary, multinodularity of HCC is the most potent predictive factor for the recurrence of HCC within 1 year of initial TACE.

Liver fibrosis progression predicts survival in patients with primary biliary cirrhosis.

The prognosis and natural history of primary biliary cirrhosis (PBC) has improved, and the clinical end‐point for PBC needs to be discovered. We aimed to identify surrogate markers for predicting long‐term prognosis in patients with PBC.