Metformin attenuates motility,contraction,and fibrogenic response of hepatic stellate cells in vivo and in vitro by activating AMP-activated protein kinase

AIM To investigate the effect of metformin on activated hepatic stellate cells(HSCs) and the possible signaling pathways involved. METHODS A fibrotic mouse model was generated by intraperitoneal injection of carbon tetrachloride(CCl_4) and subsequent treatment with or without metformin. The level of fibrosis was detected by hematoxylin-eosin staining, Sirius Red staining, and immunohistochemistry. The HSC cell line LX-2 was used for in vitro studies. The effect of metformin on cell proliferation(CCK8 assay),motility(scratch test and Transwell assay), contraction(collagen gel contraction assay), extracellular matrix(ECM) secretion(Western blot), and angiogenesis(ELISA and tube formation assay) was investigated. We also analyzed the possible signaling pathways involved by Western blot analysis.RESULTS Mice developed marked liver fibrosis after intraperitoneal injection with CCl_4 for 6 wk. Metformin decreased the activation of HSCs, reduced the deposition of ECM, and inhibited angiogenesis in CCl_4-treated mice. Platelet-derived growth factor(PDGF) promoted the fibrogenic response of HSCs in vitro, while metformin inhibited the activation, proliferation, migration, and contraction of HSCs, and reduced the secretion of ECM. Metformin decreased the expression of vascular endothelial growth factor(VEGF) in HSCs through inhibition of hypoxia inducible factor(HIF)-1α in both PDGF-BB treatment and hypoxic conditions, and it down-regulated VEGF secretion by HSCs and inhibited HSC-based angiogenesis in hypoxic conditions in vitro. The inhibitory effects of metformin on activated HSCs were mediated by inhibiting the Akt/mammalian target of rapamycin(m TOR) and extracellular signal-regulated kinase(ERK) pathways via the activation of adenosine monophosphate-activated protein kinase(AMPK).CONCLUSION Metformin attenuates the fibrogenic response of HSCs in vivo and in vitro, and may therefore be useful for the treatment of chronic liver diseases.

Effect of artesunate supplementation on bacterial translocation and dysbiosis of gut microbiota in rats with liver cirrhosis

AIM: To evaluate the effect of artesunate(AS) supplementation on bacterial translocation(BT) and gut microbiota in a rat model of liver cirrhosis. METHODS: Fifty-four male Sprague-Dawley rats were randomly divided into a normal control group(N), a liver cirrhosis group(M) and a liver cirrhosis group intervened with AS(MA). Each group was sampled at 4, 6 and 8 wk. Liver cirrhosis was induced by injection of carbon tetrachloride(CCl4), intragastric administration of 10% ethanol, and feeding a high fat diet. Rats in the MA group were intragastrically administered with AS(25 mg/kg body weight, once daily). Injuries of the liver and intestinal mucosa were assessed by hematoxylineosin or Masson's trichrome staining. Liver index was calculated as a ratio of the organ weight(g) to body weight(g). The gut microbiota was examined by automated ribosomal intergenic-spacer analysis of fecal DNA. BT was assessed by standard microbiological techniques in the blood, mesenteric lymph nodes(MLNs), liver, spleen, and kidney. RESULTS: Compared to group N, the body weight was reduced significantly in groups M and MA due to the development of liver cirrhosis over the period of 8 wk. The body weight was higher in group MA than in group M. The liver indices were significantly elevated at 4, 6 and 8 wk in groups M and MA compared to group N. AS supplementation partially decreased the liver indices in group MA. Marked histopathologic changes in the liver and small intestinal mucosa in group M were observed, which were alleviated in group MA. Levels of pro-inflammatory interleukin-6 and tumor necrosis factor-α were significantly elevated at 8 wk in ileal homogenates in group M compared to group N, which were decreased after AS supplementation in group MA. The dysbiosis of gut microbiota indicated by the mean diversity(Shannon index) and mean similarity(Sorenson index) was severe as the liver cirrhosis developed, and AS supplementation had an apparent intervention effect on the dysbiosis of gut microbiota at 4 wk. The occurrence of BT was increased in the liver of group M compared to that of group N. AS supplementation reduced BT in group MA at 8 wk. BT also occurred in the MLNs, spleen, and kidney, which was reduced by AS supplementation. BT was not detected in the blood in any group.CONCLUSION: Dysbiosis of gut microbiota, injury of intestinal mucosal barrier and BT occurred as liver cirrhosis progressed, which might enhance inflammation and aggravate liver injury. AS may have other nonantimalarial effects that modulate gut microbiota,inhibit BT and alleviate inflammation, resulting in a reduction in CCl4, alcohol and high fat-caused damages to the liver and intestine.

Oligonucleotide chip, real-time PCR and sequencing for genotyping of hepatitis B virus

To compare the oligonucleotide chip, real-time PCR and sequencing for genotyping of hepatitis B virus in Chinese patients with chronic hepatitis B. METHODS： Mixture of samples with different genotypes and clinical serum samples from 126 chronic hepatitis B patients was tested for hepatitis B virus genotypes by oligonucleotide chip, real-time PCR and sequencing of PCR products, respectively. Clinical performances, time required and costs of the three assays were evaluated. RESULTS： Oligonucleotide chips and real-time PCR detected 1% and 0.1% genotypes, respectively, in mixed samples. Of the 126 clinical samples from patients with chronic hepatitis B, genotype B was detected in 41 （33%）, 41 （33%） and 45 （36%） samples, and genotype C in 76 （60%）, 76 （60%） and 81 （64%） samples, by oligonucleotide chip, real-time PCR and sequencing, respectively. Oligonucleotide chip and real-time PCR detected mixed genotypes B and C in 9 samples. Real- time PCR was the rapidest and cheapest among the three assays. CONCLUSION： Oligonucleotide chip and real-time PCR are able to detect mixed genotypes, while sequencing only detects the dominant genotype in clinical samples.

Human umbilical cord blood-derived mononuclear cell transplantation for umbilical hernia and hepatic hydrothorax in primary biliary cirrhosis

Cell therapy was proposed as a potential treatment intervention for liver cirrhosis recently due to the fact that the therapeutic protocol for primary biliary cirrhosis (PBC)-associated refractory umbilical hernia and hepatic hydrothorax is not well defined currently. We report herein the case of a 58-year-old woman who received routine treatments for PBC, which developed into an incarcerated hernia and uncontrolled hydrothorax. This subject’s condition was significantly improved and maintained stable condition after receiving human umbilical cord blood-derived mononuclear cell (CBMC) transplantation. Consequently, this new strategy may be a potential treatment option for the refractory umbilical hernia and hydrothorax caused by PBC. However, sufficient data from large-scale controlled and double-blinded clinical trials are needed to further confirm the treatment efficacy and longterm safety before this cell transplantation can be used as a regular therapy for liver cirrhosis.

Recent advances of miRNA involvement in hepatocellular carcinoma and cholangiocarcinoma

MicroRNAs (miRNAs), which are a class of highly evolutionarily conserved non-coding RNAs, modulate gene expression and are regulated by specific genes. Several studies have shown that the expression of miRNAs is deregulated in Hepatitis C virus (HCV) & Hepatitis B virus (HBV) infection, liver cancer progression, tumor invasion and metastasis. There are a number of high-quality review articles relative to the general role of miRNA alterations in carcinogenesis and specific reviews dealing with the miRNA changes in hepatocellular carcinoma (HCC) and cholangio-carcinoma (CCA). Since primary liver cancer is predominantly comprised of HCC and intrahepatic cholangiocarcinoma (ICC), in the present review we specifically focus on recent advances of miRNAs related to tumorigenesis, invasion and metastasis of primary liver cancer, with special emphasis on their relationships to their target genes. HCV & HBV are major causes of liver disease, including acute and chronic hepatitis, liver cirrhosis, and HCC, while HCV infection is a risk factor for ICC. We also discuss the mi-RNA alterations involved in HCV & HBV infection. We briefly describe advances in molecular signaling of miRNAs in liver cancers and present insights into new therapeutic clues that target liver cancer.

Mechanisms of immune checkpoint inhibitormediated liver injury

The immune checkpoints,cytotoxic T-lymphocyte-associated antigen 4(CTLA-4) and programmed cell death protein-1/ligand-1(PD-1/PD-L1) are vital contributors to immune resulation and tolerance.Recently immune checkpoint inhibitors(ICIs) have revolutionized cancer therapy;however,they come with the cost of immune related adverse events involving multiple organs such as the liver.Due to its constant expo sure to foreign antigens,the liver has evolved a high capacity for immune tolerance,therefore,blockade of the immune checkpoints can result in aberrant immune activation affecting the liver in up to 20% of patients depending on the agent(s) used and underlying factors.This type of hepatotoxicity is termed immune mediated liver injury from checkpoint inhibitors(ILICI) and is more common when CTLA4 and PD-1/PDL1 are used in combination.The underlying mechanisms of this unique type of hepatotoxicity are not fully understood;however,the contribution of CD8^(+) cytotoxic T lymphocytes,various CD4^(+) T cells populations,cytokines,and the secondary activation of the innate immune system leading to liver injury have all been suggested.This review summarizes our current understanding of the underlying mechanisms of liver injury in immunotherapy using animal models of ILICI and available patient data from clinical studies.

Herb-Induced Liver Injury: A Global Concern

Chinese medicine and herb medicine though used to treat liver diseases are an important cause of liver injury. Many phytochemicals have the potential to injure the liver, some in a dose-related fashion and more often in an idiosyncratic fashion, meaning occurrence is uncommon to rare in the population using these treatments. As is the case with pharmaceuticals, the phytochemicals are usually tolerated despite either no or mild transient subclinical injury but rarely in some susceptible patients cause moderate to severe liver injury which is likely mediated by the adaptive immune system.

The gut microbial metabolite, 3,4-dihydroxyphenylpropionic acid, alleviates hepatic ischemia/reperfusion injury via mitigation of macrophage pro-inflammatory activity in mice

Hepatic ischemia/reperfusion injury(HIRI) is a serious complication that occurs following shock and/or liver surgery. Gut microbiota and their metabolites are key upstream modulators of development of liver injury. Herein, we investigated the potential contribution of gut microbes to HIRI.Ischemia/reperfusion surgery was performed to establish a murine model of HIRI. 16 S r RNA gene sequencing and metabolomics were used for microbial analysis. Transcriptomics and proteomics analysis were employed to study the host cell responses. Our results establish HIRI was significantly increased when surgery occurred in the evening(ZT12, 20:00) when compared with the morning(ZT0, 08:00);however, antibiotic pretreatment reduced this diurnal variation. The abundance of a microbial metabolite3,4-dihydroxyphenylpropionic acid was significantly higher in ZT0 when compared with ZT12 in the gut and this compound significantly protected mice against HIRI. Furthermore, 3,4-dihydroxyphenylpropionic acid suppressed the macrophage pro-inflammatory response in vivo and in vitro. This metabolite inhibits histone deacetylase activity by reducing its phosphorylation. Histone deacetylase inhibition suppressed macrophage pro-inflammatory activation and diminished the diurnal variation of HIRI. Our findings revealed a novel protective microbial metabolite against HIRI in mice. The potential underlying mechanism was at least in part, via 3,4-dihydroxyphenylpropionic acid-dependent immune regulation and histone deacetylase(HDAC) inhibition in macrophages.

Function of hepatocyte spheroids in bioactive microcapsules is enhanced by endogenous and exogenous hepatocyte growth factor

The ability to maintain functional hepatocytes has important implications for bioartificial liver development,cell-based therapies,drug screening,and tissue engineering.Several approaches can be used to restore hepatocyte function in vitro,including coating a culture substrate with extracellular matrix(ECM),encapsulating cells within biomimetic gels(Collagen-or Matrigel-based),or co-cultivation with other cells.This paper describes the use of bioactive heparin-based core-shell microcapsules to form and cultivate hepatocyte spheroids.These microcapsules are comprised of an aqueous core that facilitates hepatocyte aggregation into spheroids and a heparin hydrogel shell that binds and releases growth factors.We demonstrate that bioactive microcapsules retain and release endogenous signals thus enhancing the function of encapsulated hepatocytes.We also demonstrate that hepatic function may be further enhanced by loading exogenous hepatocyte growth factor(HGF)into microcapsules and inhibiting transforming growth factor(TGF)-β1 signaling.Overall,bioactive microcapsules described here represent a promising new strategy for the encapsulation and maintenance of primary hepatocytes and will be beneficial for liver tissue engineering,regenerative medicine,and drug testing applications.