Cholestasis results in intrahepatic accumulation of cytotoxic bile acids, which cause liver damage ultimately leading to biliary fibrosis and cirrhosis. Cholestatic liver injury is counteracted by a ...variety of adaptive hepatoprotective mechanisms including alterations in bile acid transport, synthesis and detoxification. The underlying molecular mechanisms are mediated mainly at a transcriptional level via a complex network involving nuclear receptors including the farnesoid X receptor, pregnane X receptor, vitamin D receptor and constitutive androstane receptor, which target overlapping, although not identical, sets of genes. Because the intrinsic adaptive response to bile acids cannot fully prevent liver injury in cholestasis, therapeutic targeting of these receptors via specific and potent agonists may further enhance the hepatic defence against toxic bile acids. Activation of these receptors results in repression of bile acid synthesis, induction of phases I and II bile acid hydroxylation and conjugation and stimulation of alternative bile acid export while limiting hepatocellular bile acid import. Furthermore, the use of nuclear receptor ligands may not only influence bile acid transport and metabolism but may also directly target hepatic fibrogenesis and inflammation. Many drugs already used to treat cholestasis and its complications such as pruritus (e.g. ursodeoxycholic acid, rifampicin, fibrates) may act via activation of nuclear receptors. More specific and potent nuclear receptor ligands are currently being developed. This article will review the current knowledge on nuclear receptors and their potential role in the treatment of cholestatic liver diseases.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
Summary It is widely known that the liver is a central organ in lipogenesis, gluconeogenesis and cholesterol metabolism. However, over the last decades, a variety of pathological conditions ...highlighted the importance of metabolic functions within the diseased liver. As observed in Western societies, an increase in the prevalence of obesity and the metabolic syndrome promotes pathophysiological changes that cause non-alcoholic fatty liver disease (NAFLD). NAFLD increases the susceptibility of the liver to acute liver injury and may lead to cirrhosis and hepatocellular cancer. Alterations in insulin response, β- oxidation, lipid storage and transport, autophagy and an imbalance in chemokines and nuclear receptor signaling are held accountable for these changes. Furthermore, recent studies revealed a role for lipid accumulation in inflammation and ER stress in the clinical context of liver regeneration and hepatic carcinogenesis. This review focuses on novel findings related to nuclear receptor signaling – including the vitamin D receptor and the liver receptor homolog 1 – in hepatic lipid and glucose uptake, storage and metabolism in the clinical context of NAFLD, liver regeneration, and cancer.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Accurate noninvasive tests (NITs) are needed to replace liver biopsy for identifying advanced fibrosis caused by nonalcoholic steatohepatitis (NASH). We analyzed screening data from two phase 3 ...trials of selonsertib to assess the ability of NITs to discriminate advanced fibrosis. Centrally read biopsies from the STELLAR studies, which enrolled patients with bridging fibrosis and compensated cirrhosis, were staged according to the NASH Clinical Research Network classification. We explored associations between fibrosis stage and NITs, including the nonalcoholic fatty liver disease fibrosis score (NFS), fibrosis‐4 (FIB‐4) index, Enhanced Liver Fibrosis (ELF) test, and liver stiffness by vibration‐controlled transient elastography (LS by VCTE). The performance of these tests to discriminate advanced fibrosis, either alone or in combinations, was evaluated using areas under the receiver operating characteristic curve (AUROCs) with 5‐fold cross‐validation repeated 100 times. Of the 4,404 patients screened for these trials, 3,202 had evaluable biopsy data: 940 with F0‐F2 fibrosis and 2,262 with F3‐F4 fibrosis. Significant differences between median values of NITs for patients with F0‐F2 versus F3‐F4 fibrosis were observed: −0.972 versus 0.318 for NFS, 1.18 versus 2.20 for FIB‐4, 9.22 versus 10.39 for ELF, and 8.8 versus 16.5 kPa for LS by VCTE (all P < 0.001). AUROCs ranged from 0.75 to 0.80 to discriminate advanced fibrosis. FIB‐4 followed by an LS by VCTE or ELF test in those with indeterminate values (FIB‐4 between 1.3 and 2.67) maintained an acceptable performance while reducing the rate of indeterminate results. Conclusion: Among patients being considered for enrollment into clinical trials, NITs alone or in combination can reduce the need for liver biopsy to discriminate advanced fibrosis caused by NASH. The predictive value of these tests for general screening will require confirmation in a real‐world population.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Tumor-infiltrating immune cells are highly relevant for prognosis and identification of immunotherapy targets in hepatocellular carcinoma (HCC). The recently developed CIBERSORT method allows immune ...cell profiling by deconvolution of gene expression microarray data. By applying CIBERSORT, we assessed the relative proportions of immune cells in 41 healthy human livers, 305 HCC samples and 82 HCC adjacent tissues. The obtained immune cell profiles provided enumeration and activation status of 22 immune cell subtypes. Mast cells were evaluated by immunohistochemistry in ten HCC patients. Activated mast cells, monocytes and plasma cells were decreased in HCC, while resting mast cells, total and naïve B cells, CD4
memory resting and CD8
T cells were increased when compared to healthy livers. Previously described S1, S2 and S3 molecular HCC subclasses demonstrated increased M1-polarized macrophages in the S3 subclass with good prognosis. Strong total immune cell infiltration into HCC correlated with total B cells, memory B cells, T follicular helper cells and M1 macrophages, whereas weak infiltration was linked to resting NK cells, neutrophils and resting mast cells. Immunohistochemical analysis of patient samples confirmed the reduced frequency of mast cells in human HCC tumor tissue as compared to tumor adjacent tissue. Our data demonstrate that deconvolution of gene expression data by CIBERSORT provides valuable information about immune cell composition of HCC patients.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Division of Gastroenterology and Hepatology, Department of
Internal Medicine, Karl-Franzens University, School of Medicine,
Graz, Austria; and Department of Medicine and Liver
Center, Yale University ...School of Medicine, New Haven,
Connecticut
Trauner, Michael and
James
L. Boyer.
Bile Salt Transporters: Molecular Characterization, Function,
and Regulation. Physiol. Rev. 83: 633-671, 2003. Molecular
medicine has led to rapid advances in the characterization of
hepatobiliary transport systems that determine the uptake and excretion
of bile salts and other biliary constituents in the liver and
extrahepatic tissues. The bile salt pool undergoes an enterohepatic
circulation that is regulated by distinct bile salt transport proteins,
including the canalicular bile salt export pump BSEP (ABCB11), the
ileal Na + -dependent bile salt transporter ISBT (SLC10A2),
and the hepatic sinusoidal Na + - taurocholate cotransporting
polypeptide NTCP (SLC10A1). Other bile salt transporters include the
organic anion transporting polypeptides OATPs (SLC21A) and the
multidrug resistance-associated proteins 2 and 3 MRP2,3 (ABCC2,3).
Bile salt transporters are also present in cholangiocytes, the renal
proximal tubule, and the placenta. Expression of these transport
proteins is regulated by both transcriptional and posttranscriptional
events, with the former involving nuclear hormone receptors where bile
salts function as specific ligands. During bile secretory failure
(cholestasis), bile salt transport proteins undergo adaptive responses
that serve to protect the liver from bile salt retention and which
facilitate extrahepatic routes of bile salt excretion. This review is a
comprehensive summary of current knowledge of the molecular
characterization, function, and regulation of bile salt transporters in
normal physiology and in cholestatic liver disease and liver regeneration.
Background and Aims
Manual histological assessment is currently the accepted standard for diagnosing and monitoring disease progression in NASH, but is limited by variability in interpretation and ...insensitivity to change. Thus, there is a critical need for improved tools to assess liver pathology in order to risk stratify NASH patients and monitor treatment response.
Approach and Results
Here, we describe a machine learning (ML)‐based approach to liver histology assessment, which accurately characterizes disease severity and heterogeneity, and sensitively quantifies treatment response in NASH. We use samples from three randomized controlled trials to build and then validate deep convolutional neural networks to measure key histological features in NASH, including steatosis, inflammation, hepatocellular ballooning, and fibrosis. The ML‐based predictions showed strong correlations with expert pathologists and were prognostic of progression to cirrhosis and liver‐related clinical events. We developed a heterogeneity‐sensitive metric of fibrosis response, the Deep Learning Treatment Assessment Liver Fibrosis score, which measured antifibrotic treatment effects that went undetected by manual pathological staging and was concordant with histological disease progression.
Conclusions
Our ML method has shown reproducibility and sensitivity and was prognostic for disease progression, demonstrating the power of ML to advance our understanding of disease heterogeneity in NASH, risk stratify affected patients, and facilitate the development of therapies.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Liver cirrhosis, the end-stage of every chronic liver disease, is not only the major risk factor for the development of hepatocellular carcinoma but also a limiting factor for anticancer therapy of ...liver and non-hepatic malignancies. Liver cirrhosis may limit surgical and interventional approaches to cancer treatment, influence pharmacokinetics of anticancer drugs, increase side effects of chemotherapy, render patients susceptible for hepatotoxicity, and ultimately result in a competitive risk for morbidity and mortality. In this review, we provide a concise overview about the impact of liver cirrhosis on the management and prognosis of patients with primary liver cancer or non-hepatic malignancies.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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