SGLT2阻害薬であるイプラグリフロジンは2型糖尿病自然発症モデルであるOLETFラットにおいて肝線維化進展を抑制する。

BACKGROUND: It is widely understood that insulin resistance (IR) critically correlates with the development of liver fibrosis in several types of chronic liver injuries. Several experiments have proved that anti-IR treatment can alleviate liver fibrosis. Sodium-glucose cotransporter 2 (SGLT2) inhibitors comprise a new class of antidiabetic agents that inhibit glucose reabsorption in the renal proximal tubules, improving IR. The aim of this study was to elucidate the effect of an SGLT2 inhibitor on the development of liver fibrosis using obese diabetic Otsuka Long-Evans Tokushima fatty (OLETF) rats and their littermate nondiabetic Long-Evans Tokushima Otsuka (LETO) rats. METHODS: Male OLETF and LETO rats were intraperitoneally injected with porcine serum twice a week for 12 weeks to augment liver fibrogenesis. Different concentrations of ipragliflozin (3 and 6 mg/kg) were orally administered during the experimental period. Serological and histological data were examined at the end of the experimental period. The direct effect of ipragliflozin on the proliferation of a human hepatic stellate cell (HSC) line, LX-2, was also evaluated in vitro. RESULTS: OLETF rats, but not LETO rats, received 12 weeks of porcine serum injection to induce severe fibrosis. Treatment with ipragliflozin markedly attenuated the development of liver fibrosis and expression of hepatic fibrosis markers, such as alpha smooth muscle actin, collagen 1A1, and transforming growth factor beta (TGF-β), and improved IR in a dose-dependent manner in OLETF rats. In contrast, the proliferation of LX-2 in vitro was not affected, suggesting that ipragliflozin had no significant direct effect on the proliferation of HSCs. CONCLUSION: In conclusion, our dataset suggests that an SGLT2 inhibitor could alleviate the development of liver fibrosis by improving IR in naturally diabetic rats. This may provide the basis for creating new therapeutic strategies for chronic liver injuries with IR.博士（医学）・甲第665号・平成29年3月15日© Japanese Society of Gastroenterology 2016The final publication is available at Springer via http://dx.doi.org/10.1007/s00535-016-1200-6

非アルコール性脂肪肝炎（NASH）モデルのラットにおいて、エンドトキシンの減少が肝星細胞の活性化抑制と腸管透過性改善を介して肝線維化進展を抑制する。

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.博士（医学）・甲第628号・平成27年3月16日Copyright: © Douhara et al. This is an open access article distributed under the terms of a Creative Commons Attribution License.The definitive version is available at " http://dx.doi.org/10.3892/mmr.2014.2995

フルクトースの経口投与はラット脂肪性肝炎モデルにおいて腸管透過性亢進作用を介して肝線維化および肝発癌を悪化させる

Recent reports have revealed the impact of a western diet containing large amounts of fructose on the pathogenesis of non-alcoholic steatohepatitis (NASH). Fructose exacerbates hepatic inflammation in NASH by inducing increasing intestinal permeability. However, it is not clear whether fructose contributes to the progression of liver fibrosis and hepatocarcinogenesis in NASH. The aim of this study was to investigate the effect of fructose intake on NASH in a rat model. A choline-deficient/L-amino acid diet was fed to F344 rats to induce NASH. Fructose was administrated to one group in the drinking water. The development of liver fibrosis and hepatocarcinogenesis were evaluated histologically. Oral fructose administration exacerbated liver fibrosis and increased the number of preneoplastic lesions positive for glutathione S-transferase placental form. Fructose-treated rats had significantly higher expression of hepatic genes related to toll-like receptor-signaling, suggesting that fructose consumption increased signaling in this pathway, leading to the progression of NASH. We confirmed that intestinal permeability was significantly higher in fructose-treated rats, as evidenced by a loss of intestinal tight junction proteins. Fructose exacerbated both liver fibrosis and hepatocarcinogenesis by increasing intestinal permeability. This observation strongly supports the role of endotoxin in the progression of NASH.博士（医学）・乙第1432号・令和元年9月27日Copyright © 2018 Impact Journals, LLCCopyright © Seki et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License 3.0 (CC BY 3.0 https://creativecommons.org/licenses/by/3.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

肝線維化におけるペリオスチンの役割 : レニン・アンギオテンシン系とクロストーク

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.博士（医学）・乙第1413号・平成30年3月15日Copyright: © Takeda et al. This is an open access article distributed under the terms of Creative Commons Attribution License(CC BY-NC-ND 4.0) https://creativecommons.org/licenses/by-nc-nd/4.0/

スルフォラファンの肝癌発育抑制効果および血管新生抑制効果に関する基礎的検討

Sulforaphane (SFN) exhibits inhibitory effects in different types of cancers. However, its inhibitory effect on liver cancer remains unknown. This study aimed to determine the therapeutic potential of SFN for the treatment of liver cancer and explore the functional mechanisms underlying the inhibitory effects of SFN. Water-Soluble Tetrazolium salt (WST-1) assay was performed to assess the in vitro effect of SFN on cell proliferation in the human liver cancer cell lines, HepG2 and Huh-7. The mRNA levels of Nrf2 target genes and cell cycle-related genes were determined using quantitative RT-PCR. For assessing the inhibitory effect of SFN in vivo, we injected immortalized liver cancer cells into BALB/c nude mice as a xenograft model. SFN was orally administrated daily after tumor inoculation and continued for thirty-five days until their sacrifices. Nrf2 activation, induced by SFN, was confirmed by mRNA upregulation of HO-1, MRP2, and NQO1 in both the cell lines. Significant inhibition of liver cancer cell proliferation by SFN was shown in vitro in a dose-dependent manner by the downregulation of CCND1, CCNB1, CDK1 and CDK2. In in vivo studies, the administration of SFN significantly reduced the subcutaneous tumor burdens at the end of experiments by suppressing tumor cell proliferation, confirmed by Ki67 immunohistochemical analysis. The mRNA levels of CCND1, CCNB1, CDK1 and CDK2 were also decreased in these SFNtreated xenograft tumors. Moreover, CD34 immunostaining elucidated that the intratumoral neovascularization was markedly attenuated in the SFN-treated xenograft tumors. SFN exerts inhibitory effect on human liver cancer cells with antiangiogenic activity. The earlier version of this study was presented at the meeting of AASLD Liver Learning on Oct 2017.博士（医学）・甲第707号・平成31年3月15日© The Author(s) 2018 Under License of Creative Commons Attribution 3.0 License https://creativecommons.org/licenses/by/3.0

肝線維化に対するファルネソイドX受容体アゴニストとジペプチジルペプチダーゼ-4阻害薬の併用効果

Aim: Non-alcoholic steatohepatitis (NASH) has a broad clinicopathological spectrum (inflammation to severe fibrosis). The farnesoid X receptor agonist obeticholic acid (OCA) ameliorates the histological features of NASH; satisfactory antifibrotic effects have not yet been reported. Here, we investigated the combined effects of OCA + a dipeptidyl peptidase-4 inhibitor (sitagliptin) on hepatic fibrogenesis in a rat model of NASH. Methods: Fifty Fischer 344 rats were fed a choline-deficient L-amino-acid-defined (CDAA) diet for 12 weeks. The in vitro and in vivo effects of OCA + sitagliptin were assessed along with hepatic fibrogenesis, lipopolysaccharide-Toll-like receptor 4 (TLR4) regulatory cascade and intestinal barrier function. Direct inhibitory effects of OCA + sitagliptin on activated hepatic stellate cells (Ac-HSCs) were assessed in vitro. Results: Treatment with OCA + sitagliptin potentially inhibited hepatic fibrogenesis along with Ac-HSC proliferation and hepatic transforming growth factor (TGF)-β1, α1(I)-procollagen, and tissue inhibitor of metalloproteinase-1 (TIMP-1) mRNA expression and hydroxyproline levels. Obeticholic acid inhibited hepatic TLR4 expression and increased hepatic matrix metalloproteinase-2 expression. Obeticholic acid decreased intestinal permeability by ameliorating CDAA diet-induced zonula occludens-1 disruption, whereas sitagliptin directly inhibited Ac-HSC proliferation. The in vitro suppressive effects of OCA + sitagliptin on TGF-β1 and α1(I)-procollagen mRNA expression and p38 phosphorylation in Ac-HSCs were almost consistent. Sitagliptin directly inhibited the regulation of Ac-HSC. Conclusions: Treatment with OCA + sitagliptin synergistically affected hepatic fibrogenesis by counteracting endotoxemia induced by intestinal barrier dysfunction and suppressing Ac-HSC proliferation. Thus, OCA + sitagliptin could be a promising therapeutic strategy for NASH.博士（医学）・甲第737号・令和2年3月16日© 2019 The Japan Society of HepatologyThis is the peer reviewed version of the following article: [https://onlinelibrary.wiley.com/doi/full/10.1111/hepr.13385], which has been published in final form at [https://doi.org/10.1111/hepr.13385]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions