Renal impairment and anemia during triple therapy

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Relationship between adipose tissue dysfunction, Vitamin D deficiency and the pathogenesis of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease ( NAFLD) is the most common chronic liver disease worldwide. Its pathogenesis is complex and not yet fully understood. Over the years many studies have proposed various pathophysiological hypotheses, among which the currently most widely accepted is the "multiple parallel hits" theory. According to this model, lipid accumulation in the hepatocytes and insulin resistance increase the vulnerability of the liver to many factors that act in a coordinated and cooperative manner to promote hepatic injury, inflammation and fibrosis. Among these factors, adipose tissue dysfunction and subsequent chronic low grade inflammation play a crucial role. Recent studies have shown that vitamin D exerts an immune-regulating action on adipose tissue, and the growing wealth of epidemiological data is demonstrating that hypovitaminosis D is associated with both obesity and NAFLD. Furthermore, given the strong association between these conditions, current findings suggest that vitamin D may be involved in the relationship between adipose tissue dysfunction and NAFLD. The purpose of this review is to provide an overview of recent advances in the pathogenesis of NAFLD in relation to adipose tissue dysfunction, and in the pathophysiology linking vitamin D deficiency with NAFLD and adiposity, together with an overview of the evidence available on the clinical utility of vitamin D supplementation in cases of NAFLD

Toll-like receptor-4 is involved in hepatic fibrogenesis in the course of non-alcoholic fatty liver disease

Toll-like receptor-4 (TLR4) is actively involved in liver in the response to injury from a variety of etiologies. Recently TLR4 expression by hepatic progenitor cells (HPC) and biliary epithelial cells has been associated to the progression of liver damage in chronic HCV-related hepatitis (1). HPC compartment activation in ductular reaction (DR) is a feature of progressive disease also in non-alcoholic fatty liver disease (NAFLD) (2). We aimed to investigate the association among TLR4 expression, HPC compartment activation and histopathologic features of fibrotic disease progression in NAFLD. Seventy-four patients who had undergone liver biopsy were included and immunohistochemistry for TLR4 was performed on hepatic tissue samples. CK-7 was used to evaluate HPC, bile ducts (BD)/ductules of DR and intermediate hepatocytes; α-smooth muscle actin was used to quantify the activation of hepatic stellate cells (HSC) and of portal/septal myofibroblasts (MF). HPC in BD/DR were responsible for the highest TLR4 intensity of staining. TLR4-positive HPC and BD/ DR correlated with fibrosis (p<0.01 and p<0.05), activity of MF (p<0.001 and p<0.05) and HSC (p<0.001 and p<0.001), portal and interface chronic inflammation (p<0.01 and p=0.01). The present study indicates the activation of the TLR4 expressing HPC compartment as important determinant of the progressive liver damage in NAFLD. TLR4 stimulation could represent one of the mechanisms directly linking the activation of HPC to inflammation and fibrosis in NAFLD

Portal and interface chronic inflammation are associated with the progenitor cell compartment activation during NAFLD

Background and aim: During nonalcoholic fatty liver disease (NAFLD), portal and interface chronic inflammation (PCI and ICI) are strongly associated with fibrosis by activation of hepatic stellate cell (HSC)s (Brunt et al., 2009; Vespasiani-Gentilucci et al., 2014). However, the determinants of PCI and ICI observed in NAFLD remain to be elucidated. Since portal and periportal ductular reaction is related to disease progression, we aimed to investigate if PCI and ICI are associated with hepatic progenitor cell (HPC) compartment activation. Methods: Fifty-two NAFLD patients were studied. NAFLD activity score, fibrosis, PCI and ICI were histologically evaluated. HPCs, intermediate hepatobiliary cells and bile ductules/interlobular bile ducts were evaluated by immunohistochemistry for CK-7, CK-19 and EpCAM. HSC and myofibroblast (MF) activity were determined by immunohistochemistry for α-SMA. Results: PCI and ICI strongly correlated with HPC compartment activation and with the activity of MFs (p≤0.001). Lobular inflammation, ballooning and HPC compartment activation were all associated with both PCI (p<0.01) and ICI (p<0.05) by univariate analysis. In the multivariate models, HPC compartment activation was independently associated with PCI and ICI (OR 4.4, 1.7-11.5; OR 3.4, 1.5-7.9, respectively). Conclusions: During NAFLD, PCI and ICI are strongly associated with HPC compartment activation and this association is likely one determinant subtending the strong association between PCI/ICI and fibrosis

Reelin expression in liver and pancreas and its correlation with liver fibrosis

Reelin is an extracellular glycoprotein secreted by a variety of cell types in both embryonic and adult tissue and plays a critical role during brain development (1,2). Reelin is up-regulated in experimental liver cirrhosis of rats in hepatic stellate cell(HSC)s, the cell type mainly implicated in liver fibrogenesis, supporting that reelin is involved in the pathogenesis of liver fibrosis (3). Pancreatic stellate cell(PSC)s share similar morphology and function to HSCs, in pancreatic fibrosis setting (4). Currently, the role of reelin in human liver and pancreas is still unclear. We investigated reelin expression in different stages of chronic liver disease in 81 liver biopsies of HCV affected patients and in pancreatic tissue near to tumoral lesions. The expression of Reelin, HSC markers (CRBP1, alpha-SMA) and Dab1, a Reelin adaptor protein, was investigated by immunohistochemistry and immunofluorescence. Reelin protein was expressed by HSCs and a strong correlation was found between Reelin expression and liver fibrosis stage (

The hepatic expression of GH/IGF1 axis components is impaired with fibrosis progression in patients with HCV-related chronic hepatitis

Background and aim: Resistance to the action of growth hormone (GH), characterized by low serum levels of insulin-like growth factor-1 (IGF1) in the face of high concentrations of GH, frequently complicates cirrhosis (Assy et al., 2008). Physiologically, the activation of GH receptor (GHR) determines phosphorylation of signal transducer and activator of transcription (STAT)-5 and the consequent induction of IGF-1 expression. The suppressor of cytokine signalling (SOCS)-3 negatively regulates this intracellular cascade. Since, to date, the hepatic expression of the GH/IGF1 axis components has been studied mainly in animal models (Blaas L et al., 2010), we aimed to evaluate their expression in the liver of patients with HCV-related chronic hepatitis. Methods: Fifty HCV patients were studied and liver samples were histologically re-evaluated for grading and staging. The expression of GH/IGF1 axis components was assessed by immunohistochemistry. Results: At the hepatocyte level, IGF-1 and phospho-STAT5 showed a negative correlation with fibrosis stage, while SOCS3 a positive one (p<0,05 for all). Furthermore, the hepatocyte expression of IGF1 was negatively correlated with its expression by hepatic stellate cells (p<0,05). Conclusions: IGF1 expression by hepatocytes was reduced with fibrosis progression, probably due to the impairment of GHR intracellular cascade. The inverse correlation between IGF1 expressed by hepatocytes and hepatic stellate cells suggests specific roles for IGF-I produced by different hepatic cells

Liver vitamin D receptor, CYP2R1 and CYP27A1 expression related to progression of metabolic and viral chronic liver damage

Background and aim: Low serum 25(OH)vitamin D3 levels were associated with the presence and prognosis of liver diseases [1]. The biological effects of 1,25(OH)2 vitamin D3 are mediated by the vitamin D receptor (VDR) and VDR has been widely detected in liver, but its expression in the course of liver disease has never been investigated [2]. We aimed to evaluate the hepatic expression of VDR and vitamin D 25-hydroxylases in patients with chronic hepatitis C (CHC) or non-alcoholic steatohepatitis (NASH) and its relationship with liver histology and serum 25(OH) vitamin D3 levels. Methods: Patients affected by CHC or NASH who had undergone liver biopsy and subjects without liver disease were included. Expression of VDR, CYP2R1 and CYP27A1 was evaluated by immunohistochemistry. Results: In CHC subjects, fibrosis stage was associated with low hepatic CYP27A1 expression, whereas in patients with VDR-negative inflammatory cells and low VDR expression on hepatocytes, the portal inflammation was significantly higher (p<0.009 and p<0.03). In NASH patients, VDR expression on cholangiocytes was inversely correlated with steatosis severity (p<0.02), lobular inflammation (p<0.01) and NAS score (p<0.03). Conclusions: The liver of patients with viral and metabolic chronic liver disease expresses VDR in a manner inversely proportional to the severity of histological lesions and a role of the vitamin D/VDR system in the progression of chronic liver damage is suggested

Hepatic Lysosomal Acid Lipase and lipophagy in the progression of NAFLD

Lysosomal Acid Lipase (LAL) is an acidic enzyme that degrades cholesterol-ester and triglyceride inside lysosomes. Both genetic LAL deficiency and non-alcoholic fatty liver disease (NAFLD) are featured by lipid accumulation in hepatocyte leading to steatosis and eventually liver failure. Recently, a deficit in blood LAL activity was found in NAFLD patient (1). Lipophagy plays a pivotal role in degradation of lipids in the liver and consists in autophagic sequestration of lipid droplets and their degradation inside lysosomes by LAL (2). p62 serves as an autophagy/lipophagy receptor for selective autophagy and accumulates when the autophagy is blocked. We aimed to evaluate the hepatic expression of LAL in NAFLD patients and healthy subjects and to verify its association with histopathological features. Furthermore, we aimed to compare LAL levels with autophagic flux and lysosomal compartment status (LAMP1-positive vesicles). LAL expression was reduced in NAFLD patients with respect to healthy subjects (

Reelin expression by hepatic stellate cells and ductular reaction in HCV related liver fibrosis

Reelin is a secreted extracellular glycoprotein that is thought to guide migrat- ing neurons during brain development and maturation cooperating with Disabled-1 (Dab1), an adaptor protein obligate effector of reelin signalling pathway (1). Reelin is also expressed in human liver by hepatic stellate cell(HSC)s that following liver injury become activated, migrating and fibrogenic cells (2). The cross-talk between HSCs and other cells such as those of ductular reaction (DR) is believed to rule liver fibrogenesis leading to cirrhosis (3). In order to better understand the role of ree- lin in human liver tissue with ongoing fibrosis, we aim to analyse the hepatic reelin expression and its relationship with the main histological determinants of the dis- ease activity and severity. Eighty-one liver biopsies of patients with chronic hepatitis C were studied. The expression of Reelin, Dab1, and HSC markers was investigated by immunohistochemistry and immunofluorescence. The Knodell histology activity index and DR score were evaluated. Activated HSC were frequently reelin positive and a statistical correlation was found between the number of reelin positive HSCs and Knodell’s stage (r= 0,3; p<0,05). Dab1 was expressed by cells of DR and the number of reelin positive HSCs correlated with DR score in mild/moderate fibrosis (r=0,4; p<0,05). Since reelin expression by HSCs correlates with increasing fibrosis and DR, whose cells in turn express Dab1, it might act as mediator in DR activation by HSCs. Further studies are needed to test reelin as useful biomarker for liver fibrosis assess- ment

Toll-like receptor-4 expression by hepatic progenitor cells and biliary epithelial cells in HCV-related chronic liver disease

Background. Toll-like receptor-4 (TLR4) is a transmembrane pattern recognition receptor that plays a key role in innate immunity by triggering inflammatory responses to Gram negative bacteria lipopolysaccharide (LPS) (1). Since liver is the main clearance organ for LPS, which is excreted in large amounts in the bile (2), it is not surprising that TLR4 has been involved in the pathogenesis of most liver diseases (3). Numerous evidences suggest a role for TLR4 in the pathogenesis of chronic hepatitis C virus (HCV) infection (4) and hepatic fibrosis (5), but the localization and level of TLR4 expression in the liver of patients with hepatitis C have never been investigated. Aim and methods. We aimed to evaluate, by means of immunohistochemistry (IHC) and real-time polymerase chain reaction (rt-PCR), hepatic TLR4 expression in patients with chronic HCV infection. Sixty-one patients with chronic HCV infection, and 12 controls free of liver disease, were included in the study. Each case was analyzed by IHC for TLR4, α–smooth muscle actin (αSMA) and cytokeratin-7 (CK-7), and a subgroup of patients and all controls by rt-PCR for TLR4. A score of activation of portal/septal myofibroblasts and lobular hepatic stellate cells (HSCs) was evaluated by IHC for α-SMA, whereas IHC for CK-7 was analysed in order to count hepatic progenitor cells (HPCs), interlobular bile ducts and intermediate hepatocytes. Results. The parenchimal elements responsible for the highest TLR4 level of expression were HPCs and biliary epithelial cells (BECs) of interlobular bile ducts in the infected group. Double-labeling experiments with anti-TLR4, anti-CK7 and anti-CD133 confirmed this finding. TLR4-positive HPCs and interlobular bile ducts were significantly correlated with the stage of liver disease (p<0.001), the grade of inflammation (p<0.001), and with the activity of portal/septal myofibroblasts (p<0.001). Rt-PCR study confirmed an increased TLR4 expression in the 26 patients analyzed with respect to controls (p<0.001). TLR4 expression positively correlated with fibrosis (p<0.05) and inflammation (p<0.05). Conclusions. The expression of TLR4 in HPCs and BECs in HCV-related liver damage significantly correlates with inflammation, activation of portal/septal myofibroblasts and fibrosis. 1) Beutler. Nature 2004;430:257-63; 2) Van Bossuyt et al. J Hepatol 1988;7:325-37; 3) Seki et al. Hepatology 2008;48:322-35; 4) Machida et al. J Virol 2006;80:866-74. 5) Seki et al. Nat Med 2007;13:1324-32