Primary biliary cholangitis (PBC), an autoimmune liver disease occurring predominantly in women, is characterized by high titers of serum anti-mitochondrial antibodies (AMAs) and progressive intrahepatic cholestasis. The immune system plays a critical role in PBC pathogenesis and a variety of immune cell subsets have been shown to infiltrate the portal tract areas of patients with PBC. Amongst the participating immune cells, CD4 T cells are important cytokine-producing cells that foster an inflammatory microenvironment. Specifically, these cells orchestrate activation of other immune cells, including autoreactive effector CD8 T cells that cause biliary epithelial cell (BEC) injury and B cells that produce large quantities of AMAs. Meanwhile, other immune cells, including dendritic cells (DCs), natural killer (NK) cells, NKT cells, monocytes, and macrophages are also important in PBC pathogenesis. Activation of these cells initiates and perpetuates bile duct damage in PBC patients, leading to intrahepatic cholestasis, hepatic damage, liver fibrosis, and eventually cirrhosis or even liver failure. Taken together, the body of accumulated clinical and experimental evidence has enhanced our understanding of the immunopathogenesis of PBC and suggests that immunotherapy may be a promising treatment option. Herein, we summarize current knowledge regarding immunological abnormalities of PBC patients, with emphasis on underlying pathogenic mechanisms. The differential immune response which occurs over decades of disease activity suggests that different therapies may be needed at different stages of disease.

Skeletal muscle is a tissue that represents 30–40% of total body mass in healthy humans and contains up to 75% of total body proteins. It is thus the largest organ in non-obese subjects. The past few years have seen increasing awareness of the prognostic value of appreciating changes in skeletal muscle compartment in various chronic diseases. Hence, a low muscle mass, a low muscle function and muscle fatty infiltration are linked with poor outcomes in many pathological conditions. In particular, an affluent body of evidence links the severity, the complications and mortality of chronic liver disease (CLD) with skeletal muscle depletion. Yet it is still not clear whether low muscle mass is a cause, an aggravating factor, a consequence of the ongoing disease, or an epiphenomenon reflecting general alteration in the critically ill patient. The mechanisms by which the muscle compartment influences disease prognosis are still largely unknown. In addition, whether muscle alterations contribute to liver disease progression is an unanswered question. Here, we first review basic knowledge about muscle compartment to draw a conceptual framework for interpreting skeletal muscle alteration in CLD. We next describe recent literature on muscle wasting in cirrhosis and liver transplantation. We then discuss the implication of skeletal muscle compartment in non-alcoholic fatty liver disease (NAFLD)/non-alcoholic steatohepatitis (NASH), focusing on plausible metabolic disruption in muscle compartment that might participate in NAFLD progression. Finally, we discuss shortcomings and challenges we need to address in the near future prior to designate the muscle compartment as a therapeutic target in CLD.

Liver cirrhosis is accompanied by increased intrahepatic resistance and angiogenesis-related portosystemic collaterals formation. Diabetic patients suffer from abnormal vasoresponsiveness and angiogenesis that can be ameliorated by glucose control. However, the relevant presentation is not clear in those with cirrhosis and diabetes, in whom insulin is the treatment of choice. Liver cirrhosis was induced in Sprague–Dawley rats with common bile duct ligation (BDL) and sham rats were used as controls. Streptozotocin 60 mg/kg (STZ, i.p., to induce diabetes) or vehicle was injected. The rats received BDL and STZ injections were injected with insulin or vehicle. On the 29th day after the procedure, the groups were surveyed for (1) systemic and portal hemodynamics; (2) mesenteric vascular density; (3) severity of portosystemic collaterals; (4) hepatic resistance using in situ liver perfusion; (5) histology survey of mesentery and liver; and (6) mesentery angiogenesis- and liver fibrogenesis-related protein expressions. Compared with the cirrhotic rats, the cirrhotic diabetic rats had lower body weight, cardiac output, superior mesenteric arterial (SMA) resistance and portal venous (PV) resistance, and higher SMA and PV flow, which were mostly reversed by insulin. The cirrhotic diabetic rats also had increased mesenteric vascular density, and enhanced pERK, pAkt, VEGF, VEGFR2 protein expressions that were reversed by insulin. Insulin decreased the degree of shunting in the diabetic cirrhotic rats. Hepatic perfusion pressure and severity of liver fibrosis were not significantly influenced by diabetes and insulin treatment in the cirrhotic rats. In conclusion, diabetes aggravated hemodynamic derangements, mesenteric angiogenesis and collaterals in the cirrhotic rats, which were mostly ameliorated by insulin. Further clinical investigations are warranted.

Data on the consequences of cirrhosis regression on portal hypertension and on splanchnic and systemic hemodynamic are scarce. Previous studies have reported a decrease in hepatic venous pressure gradient following antiviral treatment in patients with hepatitis B or C related cirrhosis. However, these studies did not investigate splanchnic and systemic hemodynamic changes associated with virus control. To fill this gap in knowledge, in a recent issue of Clinical Science , Hsu et al. (vol. 132, issue 6, 669-683) used rat models of cirrhosis induced by thioacetamide and by bile duct ligation and provided a comprehensive analysis of the effects of cirrhosis regression on splanchnic and systemic hemodynamics. They observed a significant reduction in portal pressure accompanied by a normalization of systemic hemodynamic (normal cardiac index and systemic vascular resistance) and a decrease in intrahepatic vascular resistance. No change in extrahepatic vascular structures were observed despite normalization of collateral shunting, meaning that portosystemic collaterals persist but are not perfused. One intriguing part of their results is the only marginal effect of cirrhosis regression on liver hyperarterialisation. This result suggests that changes in splanchnic hemodynamic features induced by cirrhosis remain when hepatic vascular resistance decreases, raising the hypothesis of an autonomous mechanism persisting despite regression of intrahepatic vascular resistance. Microbiota changes and bacterial translocation might account for this effect. In conclusion cirrhosis regression normalizes systemic hemodynamics, but some splanchnic hemodynamic changes persist including extrahepatic angiogenesis and liver hyperarterialization.

In this issue of Clinical Science , Schueller et al. [Clin. Sci. (2017) 131, 1971-1987] evaluated the role of miR-223 across multiple etiologies of acute and chronic liver insults in murine models and clinical samples. The authors find that while miR-223 is not mechanistically involved in liver injury, its intracellular levels in hepatocytes are increased upon hepatic damage in a broad panel of mechanistically distinct injury models. Furthermore, the authors provide evidence that circulating miR-223 levels provide a promising minimally invasive biomarker for acute liver failure (ALF) that defines a distinct subset of ALF cases and correlates with clinical outcomes. Combined, the highlighted study suggests that miR-223 constitutes a promising biomarker whose clinical validity and utility warrant further investigations.

Cirrhotic portal hypertension is characterized by increased hepatic oxidative stress, AA (arachidonic acid)-derived TXA 2 (thromboxane A 2 ) release and exaggerated hepatic response to the α-adrenergic agonist MTX (methoxamine). Besides promoting hepatic fibrosis, the role of hyperleptinaemia in the modulation of vascular response in NASH (non-alcoholic steatohepatitis) rat livers remains unknown. The aim of the present study was to explore the possible links between hyperleptinaemia and the disarrangement in the hepatic microcirculation. NASH-cirrhosis with hyperleptinaemia was induced in lean rats by feeding with an HF/MCD (high-fat/methionine-choline-deficient) diet. Portal haemodynamics, various substances, protein and mRNA expression and PUFA (polyunsaturated fatty acid) composition were measured. Finally, the effects of leptin pre-infusion on TXA 2 release and concentration–PPP (portal perfusion pressure) curves in response to MTX were evaluated by simultaneously pre-treatment with the Kupffer cell inactivators GdCl 3 (gadolinium chloride) or EC (encapsulated clodronate), the TXS (TXA 2 synthase) inhibitor furegrelate, the TP receptor (TXA 2 receptor) antagonist SQ29548 and the dual TXS/TP receptor antagonist BM567. In HF/MCD+leptin-lean rats, cirrhosis-induced PPP and MTX hyper-responsiveness were associated with increased hepatic TXA 2 production, TBARS (thiobarbituric acid-reacting substances) levels and the AA (arachidonic acid)/ n −3 PUFA ratio, and up-regulation of hepatic leptin, FAS (fatty acid synthase), NADPH oxidase subunits, TXS, TP receptor, TGFβ 1 (transforming growth factor β 1 ) proteins and mRNAs. Pre-infusion of leptin significantly enhanced MTX-stimulated PPP elevation and TXA 2 release, which were attenuated by GdCl 3 and EC pre-treatment. Concomitantly pre-incubation with BM567, but not furegrelate or SQ29548, significantly abolished the leptin-enhanced MTX-stimulated increase in PPP in NASH-cirrhotic rats. Hyperleptinaemia plays an important role in hyper-responsiveness to MTX in NASH-cirrhotic rat livers with portal hypertension. The leptin-enhanced MTX-stimulated increase in PPP is mediated by increased oxidative stress and Kupffer-cell-activated AA-derived TXA 2 release in NASH-cirrhotic rats.

The RAS (renin–angiotensin system) is now recognized as an important regulator of liver fibrosis and portal pressure. Liver injury stimulates the hepatic expression of components of the RAS, such as ACE (angiotensin-converting enzyme) and the AT 1 receptor [AngII (angiotensin II) type 1 receptor], which play an active role in promoting inflammation and deposition of extracellular matrix. In addition, the more recently recognized structural homologue of ACE, ACE2, is also up-regulated. ACE2 catalyses the conversion of AngII into Ang-(1–7) [angiotensin-(1–7)], and there is accumulating evidence that this ‘alternative axis’ of the RAS has anti-fibrotic, vasodilatory and anti-proliferative effects, thus counterbalancing the effects of AngII in the liver. The RAS is also emerging as an important contributor to the pathophysiology of portal hypertension in cirrhosis. Although the intrahepatic circulation in cirrhosis is hypercontractile in response to AngII, resulting in increased hepatic resistance, the splanchnic vasculature is hyporesponsive, promoting the development of the hyperdynamic circulation that characterizes portal hypertension. Both liver fibrosis and portal hypertension represent important therapeutic challenges for the clinician, and there is accumulating evidence that RAS blockade may be beneficial in these circumstances. The present review outlines new aspects of the RAS and explores its role in the pathogenesis and treatment of liver fibrosis and portal hypertension.

HCV (hepatitis C virus) represents one of the major health problems worldwide, as almost 170 million people are infected and most of these develop a chronic disease, often with the progression to cirrhosis and its complications. In the present issue of Clinical Science , Iwata and co-workers report an association between a variant of a gene regulating bile acid levels, ABCB11 1331T>C (where ABCB11 encodes ATP-binding cassette, subfamily B, member 11), and the progression to cirrhosis in patients with HCV, but not in fatty liver patients. They correlate this genetic variant with increased serum bile acid levels as a marker of cholestasis. These findings have important implications for researchers working to dissect the molecular mechanisms underlying liver fibrogenesis and disease progression; however, the implications for clinical hepatologists are less immediate.

Chronic HCV (hepatitis C virus)-associated cirrhosis represents a major indication for liver transplantation. Bile acids contribute to hepatic stellate cell activation as a key event in fibrogenesis. The aim of the present study was to investigate the role of bile acids and polymorphisms in bile acid level-regulating genes on fibrosis progression. A total of 206 subjects with chronic HCV infection were included for ABCB11 (ATP-binding cassette, subfamily B, member II) 1331T>C and NR1H4 (nuclear receptor) −1G>T genotyping, 178 of which were analysed for fibrosis stage. Exclusion criteria were HBV (hepatitis B virus) or HIV coinfection, alcohol >40 g/day and morbid obesity. A total of 358 patients with NAFLD (non-alcoholic fatty liver disease) were genotyped for comparison with a non-viral liver disease. Caucasian individuals ( n = 110), undergoing liver resection for focal hepatic metastasis, served as controls. The ABCB11 1331C allele was significantly overrepresented in HCV patients compared with controls {allelic frequency 62.9%; OR (odds ratio), 1.41 [95% CI (confidence interval), 1.012–1.965]}. Median plasma bile acid levels were not significantly increased in the CC compared with TT genotype [7.2 (1–110) μmol/l compared with 3.5 (1–61) μmol/l; values are medians (range). A significant association between the presence of cirrhosis and ABCB11 genotype (CC compared with CT or TT, P =0.047) was observed in the χ 2 test and independent of other risk factors of age, gender, body mass index and disease duration in multivariate analysis ( P = 0.010). No such association could be observed in fatty liver patients with regard to advanced fibrosis ( F ≥2). The common ABCB11 1331CC genotype, which is present in 40% of HCV patients and renders the carrier susceptible to increased bile acid levels, is associated with cirrhosis.

Circulating miRNAs (microRNAs) are emerging as promising biomarkers for several pathological conditions, and the aim of this study was to investigate the feasibility of using serum miRNAs as biomarkers for liver pathologies. Real-time qPCR (quantitative PCR)-based TaqMan MicroRNA arrays were first employed to profile miRNAs in serum pools from patients with HCC (hepatocellular carcinoma) or LC (liver cirrhosis) and from healthy controls. Five miRNAs (i.e. miR - 885 - 5p , miR-574-3p , miR-224 , miR -215 and miR - 146a ) that were up-regulated in the HCC and LC serum pools were selected and further quantified using real-time qPCR in patients with HCC, LC, CHB (chronic hepatitis B) or GC (gastric cancer) and in normal controls. The present study revealed that more than 110 miRNA species in the serum samples and wide distribution ranges of serum miRNAs were observed. The levels of miR - 885 - 5p were significantly higher in sera from patients with HCC, LC and CHB than in healthy controls or GC patients. miR - 885 - 5p yielded an AUC [the area under the ROC (receiver operating characteristic) curve] of 0.904 [95% CI (confidence interval), 0.837–0.951, P <0.0001) with 90.53% sensitivity and 79.17% specificity in discriminating liver pathologies from healthy controls, using a cut off value of 1.06 (normalized). No correlations between increased miR - 885 - 5p and liver function parameters [AFP (α-fetoprotein), ALT (alanine aminotransferase), AST (aspartate aminotransferase) and GGT (γ-glutamyl transpeptidase)] were observed in patients with liver pathologies. In summary, miR - 885 - 5p is significantly elevated in the sera of patients with liver pathologies, and our data suggest that serum miRNAs could serve as novel complementary biomarkers for the detection and assessment of liver pathologies.

Adiponectin, which plays a pivotal role in metabolic liver diseases, is reduced in concentration in patients with NASH (non-alcoholic steatohepatitis). The aim of the present study was to determine adiponectin concentrations in patients with different forms and stages of chronic liver diseases. Serum adiponectin concentrations were measured in 232 fasting patients with chronic liver disease: 64 with NAFLD (non-alcoholic fatty liver disease), 123 with other chronic liver disease (e.g. viral hepatitis, n =71; autoimmune disease, n =18; alcohol-induced liver disease, n =3; or elevated liver enzymes of unknown origin, n =31) and 45 with cirrhosis. Circulating adiponectin levels were significantly lower in patients with NAFLD in comparison with patients with other chronic liver disease (4.8±3.5 compared with 10.4±6.3 μg/ml respectively; P <0.0001). Circulating adiponectin levels were significantly higher in patients with cirrhosis in comparison with patients without cirrhosis (18.6±14.5 compared with 8.4±6.1 μg/ml respectively; P <0.0001). Adiponectin concentrations correlated negatively with body weight ( P <0.001), serum triacylglycerols (triglycerides) ( P <0.001) and, in women, with BMI (body mass index) ( P <0.001). Adiponectin concentrations correlated positively with serum bile acids ( P <0.001), serum hyaluronic acid ( P <0.001) and elastography values ( P <0.001). Adiponectin levels were decreased in patients with NAFLD. In conclusion, adiponectin levels correlate positively with surrogate markers of hepatic fibrosis (transient elastography, fasting serum bile acids and hyaluronate) and are significantly elevated in cases of cirrhosis.

Our present study examines, in mesenteric resistance arteries, possible vasodilation alterations, and the role of NO and COX (cyclo-oxygenase) derivatives, in cirrhosis. The vasodilator response to acetylcholine was analysed in segments from control and cirrhotic rats. The effects of the non-specific COX inhibitor indomethacin, the specific COX-1 inhibitor SC-560 and the specific COX-2 inhibitor NS-398 were analysed in segments from both groups of rats. NO release was measured, and eNOS [endothelial NOS (NO synthase)], phospho-eNOS, iNOS (inducible NOS), COX-1 and COX-2 protein expression was also analysed. The effects of the TP receptor [TXA 2 (thromboxane A 2 ) receptor] antagonist SQ 29548, the TXA 2 synthesis inhibitor furegrelate, the PGI 2 (prostaglandin I 2 ) synthesis inhibitor TCP (tranylcypromine) or TCP+furegrelate were only determined in segments from cirrhotic rats. The vasodilator response to acetylcholine was higher in segments from cirrhotic rats. Indomethacin, SC-560 and NS-398 did not modify the vasodilator response in control rats; however, indomethacin, NS-398 and TCP+furegrelate increased, whereas SC-560 did not modify and SQ 29548, furegrelate or TCP decreased, the vasodilator response to acetylcholine in cirrhotic rats. NO release was higher in cirrhotic rats. Furegrelate decreased, whereas TCP+furegrelate increased, the NO release in segments from cirrhotic rats. eNOS and COX-1 protein expression was not modified, whereas phosho-eNOS, iNOS and COX-2 protein expression was higher in cirrhotic rats. Therefore the increase in iNOS expression and eNOS activity may mediate increases in endothelial NO release. The COX-2 derivatives TXA 2 and PGI 2 may act simultaneously, producing a compensatory effect that reduces NO release and may limit the hyperdynamic circulation.

Increasing NO bioavailability improves hepatic endothelial dysfunction, which ameliorates intrahepatic resistance and portal hypertension. Acute administration of sildenafil increases hepatic production of NO with a reduction in hepatic sinusoid resistance in cirrhotic patients and enhances the vasorelaxation response to NO in cirrhotic rat livers. However, the mechanisms were still unclear. Therefore, our present study aims to evaluate the effects and mechanisms of administration of sildenafil for 1 week on the hepatic microcirculation of cirrhotic rats. Cirrhosis was induced by bile duct ligation with sham-operated rats serving as normal controls. Intrahepatic resistance was evaluated by in situ liver perfusion. Expression of phospho-eNOS (endothelial NO synthase), iNOS (inducible NO synthase), phospho-Akt, PDE-5 (phosphodiesterase-5) and sGC (soluble guanylate cyclase) were determined by Western blot analysis. Biosynthesis of BH 4 (tetrahydrobiopterin) and GTPCH-I (GTP cyclohydrolase I) activity were examined by HPLC. Intravital microscopy was used to observe the direct change in hepatic microcirculation. In cirrhotic rat livers, sildenafil treatment increased hepatic sinusoid volumetric flow, NO bioavailability, BH 4 , GTPCH-I activity, and the protein expression of phospho-Akt, phospho-eNOS and sGC. These events were associated with reduced protein expression of PDE-5, portal perfusion pressure and portal vein pressure. In contrast, sham rats did not produce any significant change in these measurements. In conclusion, sildenafil treatment improves endothelial dysfunction by augmenting NO bioavailability in the hepatic microcirculation.

Ang-(1–7) (angiotensin-1–7), a peptide product of the recently described ACE (angiotensin-converting enzyme) homologue ACE2, opposes the harmful actions of AngII (angiotensin II) in cardiovascular tissues, but its role in liver disease is unknown. The aim of the present study was to assess plasma levels of Ang-(1–7) in human liver disease and determine its effects in experimental liver fibrosis. Angiotensin peptide levels were measured in cirrhotic and non-cirrhotic patients with hepatitis C. The effects of Ang-(1–7) on experimental fibrosis were determined using the rat BDL (bile-duct ligation) model. Liver histology, hydroxyproline quantification and expression of fibrosis-related genes were assessed. Expression of RAS (renin–angiotensin system) components and the effects of Ang-(1–7) were examined in rat HSCs (hepatic stellate cells). In human patients with cirrhosis, both plasma Ang-(1–7) and AngII concentrations were markedly elevated ( P <0.001). Non-cirrhotic patients with hepatitis C had elevated Ang-(1–7) levels compared with controls ( P <0.05), but AngII concentrations were not increased. In BDL rats, Ang-(1–7) improved fibrosis stage and collagen Picrosirius Red staining, and reduced hydroxyproline content, together with decreased gene expression of collagen 1A1, α-SMA (smooth muscle actin), VEGF (vascular endothelial growth factor), CTGF (connective tissue growth factor), ACE and mas [the Ang-(1–7) receptor]. Cultured HSCs expressed AT 1 Rs (AngII type 1 receptors) and mas receptors and, when treated with Ang-(1–7) or the mas receptor agonist AVE 0991, produced less α-SMA and hydroxyproline, an effect reversed by the mas receptor antagonist A779. In conclusion, Ang-(1–7) is up-regulated in human liver disease and has antifibrotic actions in a rat model of cirrhosis. The ACE2/Ang-(1–7)/ mas receptor axis represents a potential target for antifibrotic therapy in humans.

A prolongation of QT interval has been shown in patients with cirrhosis and it is considered as part of the definition of the so-called ‘cirrhotic cardiomyopathy’. The aim of the present study was to assess the determinants of QT interval prolongation in cirrhotic patients. Forty-eight male patients with different stages of liver disease were divided into three subgroups according to the Child–Pugh classification. All patients underwent a 24-h ECG Holter recording. The 24-h mean of QT intervals corrected for heart rate (termed QTc) and the slope of the regression line QT/RR were calculated. HRV (heart rate variability), plasma calcium and potassium concentration and HVPG (hepatic venous pressure gradient) were measured. QTc was progressively prolonged from Child A to Child C patients ( P =0.001). A significant correlation between QTc and HVPG was found ( P =0.003). Patients with alcohol-related cirrhosis presented QTc prolongation more frequently than patients with post-viral cirrhosis ( P <0.001). The QT/RR slope was steeper in subjects with alcoholic aetiology as compared with viral aetiology ( P =0.02), suggesting that these patients have a further QTc prolongation when heart rate decreases. The plasma calcium concentration was inversely correlated with QTc ( P <0.001). The presence of severe portal hypertension was associated with decreased HRV ( P <0.001). Cirrhotic patients with a more severe disease, especially of alcoholic aetiology, who have greater HVPG and lower calcium plasma levels, have an altered ventricular repolarization and a reduced vagal activity to the heart, which may predispose to life-threatening arrhythmias.

Liver cirrhosis is characterized by increased IHR (intrahepatic resistance) and lipid peroxidation, and decreased antioxidative defence. The present study investigates the effects of administration for 1 month of the antioxidant UDCA (ursodeoxycholic acid) in BDL (bile-duct-ligated) cirrhotic rats. Splanchnic haemodynamics, IHR, hepatic levels of TBARS (thiobarbituric acid-reacting substances), GSH (glutathione), SOD (superoxide dismutase) activity, nitrite, PIIINP (N-terminal propeptide of type III procollagen) and collagen deposition, histological examination of liver, mRNA expression of PIIIP-α 1 (type III procollagen) and TGF-β1 (transforming growth factor-β 1 ), protein expression of TXS (thromboxane synthase) and iNOS (inducible NO synthase), and TXA 2 (thromboxane A 2 ) production in liver perfusates were measured. The results showed that portal pressure and IHR, hepatic levels of PIIINP, hepatic collagen deposition, mRNA expression of PIIIP-α 1 and TGF-β 1 , protein expression of iNOS and TXS, and production of TXA 2 in liver perfusates were significantly decreased in UDCA-treated BDL rats. The increased levels of hepatic GSH and SOD activity and decreased levels of TBARS and nitrite were also observed in UDCA-treated BDL rats. In UDCA-treated BDL rats, the reduction in portal pressure resulted from a decrease in IHR, which mostly acted through the suppression of hepatic TXA 2 production and lipid peroxidation, and an increase in antioxidative defence, leading to the prevention of hepatic fibrosis.

Recent studies have shown that the activated endocannabinoid system participates in the increase in IHR (intrahepatic resistance) in cirrhosis. The increased hepatic production of vasoconstrictive eicosanoids is involved in the effect of endocannabinoids on the hepatic microcirculation in cirrhosis; however, the mechanisms of these effects are still unknown. The aim of the present study was to investigate the effects of chronic CB 1 (cannabinoid 1) receptor blockade in the hepatic microcirculation of CBL (common bile-duct-ligated) cirrhotic rats. After 1 week of treatment with AM251, a specific CB 1 receptor antagonist, IHR, SMA (superior mesenteric artery) blood flow and hepatic production of eicosanoids [TXB 2 (thromboxane B 2 ), 6-keto PGF 1α (prostaglandin F 1α ) and Cys-LTs (cysteinyl leukotrienes)] were measured. Additionally, the protein levels of hepatic COX (cyclo-oxygenase) isoforms, 5-LOX (5-lipoxygenase), CB 1 receptor, TGF-β 1 (transforming growth factor β 1 ), cPLA 2 [cytosolic PLA 2 (phospholipase A 2 )], sPLA 2 (secreted PLA 2 ) and collagen deposition were also measured. In AM251-treated cirrhotic rats, a decrease in portal venous pressure was associated with the decrease in IHR and SMA blood flow. Additionally, the protein levels of hepatic CB 1 receptor, TGF-β 1 , cPLA 2 and hepatic collagen deposition, and the hepatic levels of 5-LOX and COX-2 and the corresponding production of TXB 2 and Cys-LTs in perfusates, were significantly decreased after 1 week of AM251 treatment in cirrhotic rats. Furthermore, acute infusion of AM251 resulted in a decrease in SMA blood flow and an increase in SMA resistance in CBL rats. In conclusion, the chronic effects of AM251 treatment on the intrahepatic microcirculation were, at least partly, mediated by the inhibition of hepatic TGF-β 1 activity, which was associated with decreased hepatic collagen deposition and the activated PLA 2 /eicosanoid cascade in cirrhotic livers.

Liver fibrosis represents a major worldwide health care burden. The last 15 years have seen a rapid growth in our understanding of the pathogenesis of this clinically relevant model of inflammation and repair. This work is likely to inform the design of effective antifibrotic therapies in the near future. In this review, we examine how the innate and adaptive immune response interacts with other key cell types in the liver, such as the myofibroblast, regulating the process of hepatic fibrosis and, where relevant, resolution of fibrosis with remodelling. Emphasis is placed on the increasing knowledge that has been generated by the use of transgenic animals and animals in which specific cell lines have been deleted. Additionally, we review the increasing evidence that, although significant numbers of wound-healing myofibroblasts are derived from the hepatic stellate cell, significant contributions may occur from other cell lineages, including those from distant sites such as bone marrow stem cells.

HCV (hepatitis C virus) has a high propensity to persist and to cause chronic hepatitis C, eventually leading to cirrhosis. Since HCV itself is not cytopathic, liver damage in chronic hepatitis C is commonly attributed to immune-mediated mechanisms. HCV proteins interact with several pathways in the host's immune response and disrupt pathogen-associated pattern recognition pathways, interfere with cellular immunoregulation via CD81 binding and subvert the activity of NK (natural killer) cells as well as CD4 + and CD8 + T-cells. Finally, HCV-specific T-cells become increasingly unresponsive and apparently disappear, owing to several possible mechanisms, such as escape mutations in critical viral epitopes, lack of sufficient help, clonal anergy or expansion of regulatory T-cells. The role of neutralizing antibodies remains uncertain, although it is still possible that humoral immunity contributes to bystander damage of virally coated cells via antibody-dependent cellular cytotoxicity. Cytotoxic lymphocytes kill HCV-infected cells via the perforin/granzyme pathway, but also release Fas ligand and inflammatory cytokines such as IFNγ (interferon γ). Release of soluble effector molecules helps to control HCV infection, but may also destroy uninfected liver cells and can attract further lymphocytes without HCV specificity to invade the liver. Bystander damage of these non-specific inflammatory cells will expand the tissue damage triggered by HCV infection and ultimately activate fibrogenesis. A clear understanding of these processes will eventually help to develop novel treatment strategies for HCV liver disease, independent from direct inhibition of HCV replication.

Abnormal vascular tone is responsible for many of the complications seen in cirrhosis making the identification of the pathophysiology of abnormal dilatation a major focus in hepatology research. The study of abnormal vascular tone is complicated by the multiple vascular beds involved (hepatic, splanchnic, peripheral, renal and pulmonary), the differences in the underlying cause of portal hypertension (hepatic versus pre-hepatic) and the slow evolution of the hyperdynamic state. The autonomic nervous system, circulating vasodilators and abnormalities in vascular smooth muscle cells (receptors, ion channels, signalling systems and contraction) have all been implicated. There is overwhelming evidence for an overproduction of NO (nitric oxide) contributing to the peripheral dilatation in both animal models of, and in humans with, cirrhosis and portal hypertension. This review focuses on the proposal that endotoxaemia, possibly from gut-derived bacterial translocation, causes induction of NOS (NO synthase) leading to increased vascular NO production, which is the primary stimulus for the development of vasodilatation in cirrhosis and its accompanying clinical manifestations. The current controversy lies not in whether NO production is elevated, but in which isoform of NOS is responsible. We review the evidence for endotoxaemia in cirrhosis and the factors contributing to gut-derived bacterial translocation, including intestinal motility and permeability, and finally discuss the possible role of selective intestinal decontamination in the management of circulatory abnormalities in cirrhosis.

Advanced cirrhosis is associated with reduced platelet function and altered renal function and sodium handling. Arachidonic acid (AA) metabolites contribute to platelet aggregation and to maintain the response to diuretics in advanced cirrhosis. In the present study, we tested the effects of a dietary supplementation for 8 weeks with a triacylglycerol (triglyceride) enriched in AA (ARASCO®; 4 g/day) or oleic acid (OA) on plasma and membrane fatty acid composition, platelet aggregation and renal prostaglandin (PG) metabolism. At baseline, all patients had reduced platelet aggregation. Patients treated with AA showed a significant increase in the percentage of AA in plasma lipids and membrane phospholipids. These changes were associated with an increased platelet aggregation in response to collagen (from 55.83±20.63 to 67.67±14.44%; P <0.05). At baseline, all urinary AA metabolites, including PGE 2 , 6-keto-PGF 1α , 8-epi-PGF 2α and 11-dehydro-thromboxane B 2 , were elevated in cirrhotic patients when compared with a group of normal subjects. After furosemide treatment, urinary excretion of 11-dehydro-thromboxane B 2 increased significantly. Supplementation with AA did not result in any significant change in urinary PG excretion either before or after diuretic administration. The results of the present study show that dietary supplementation with AA effectively increases the levels of this fatty acid in plasma and membrane phospholipids and improves platelet aggregation. These data suggest a possible novel approach to the treatment of the haemostatic defect observed in these patients.

Matrix metalloproteinases (MMPs) are central to tissue remodelling; however, little is known about the temporal pattern and differential regulation of hepatic MMP expression in the course of chronic human liver disease. Using quantitative reverse transcription–PCR ELISA assays, we studied hepatic mRNA expression of MMP-1, -2, -3, -7, -9, -10, -11, -13 and -14 in patients with chronic hepatitis C and hepatitis C virus-induced end-stage liver cirrhosis and controls. Results were compared with histology, hepatic expression of tissue inhibitor of metalloproteinases (TIMP)-1, -2 and -3, procollagen types I and IV, laminin, and with circulating protein levels of hyaluronate, TIMP-1 and -2 and MMP proenzymes, as measured by ELISA. The impact of the MMP-3(-1171) promoter polymorphism on hepatic MMP-3 expression was analysed. Hepatic mRNA expression data identified differentially regulated groups of MMPs during the course of chronic hepatitis C, showing either steadily increasing mRNA expression with disease progression (MMP-1, -2, -7 and -14) or transiently elevated expression (MMP-9, -11 and -13). The first group closely correlated to the parameters of fibrogenesis. Hepatic MMP-3 expression was unrelated to disease stage, but was determined by the MMP-3(-1171) promoter polymorphism. In conclusion, MMP expression during the course of chronic hepatitis C appears to be a closely regulated process, with different clusters of coordinately regulated MMP genes being identified.

Bradykinin, a nonapeptide with vasodilatory and permeabilizing activity, is generated through the cleavage of high- M r (‘high-molecular-weight’) kininogen by kallikrein, and its generation is facilitated by plasmin. In the ascitic fluid of patients with cirrhosis, there is massive cleavage of high- M r kininogen and activation of fibrinolysis, but bradykinin has never been measured directly. In the ascitic fluid of 24 patients with cirrhosis, we measured bradykinin-(1-9)-nonapeptide levels by RIA after liquid-phase and subsequent HPLC extraction, and those of its catabolic product bradykininin-(1-5)-pentapeptide by ELISA after liquid-phase extraction. Cleaved high- M r kininogen, activated factor XII and plasmin-antiplasmin complexes were measured in ascitic fluid and plasma. Plasma renin activity (PRA) was also determined. As a control, we also analysed plasma from 24 healthy subjects matched for sex and age with the patients. In the ascitic fluid from patients with cirrhosis, the median bradykinin-(1-9) concentration was 3.3fmol/ml (range 0.2-29.0fmol/ml), and the median bradykinin-(1-5) concentration was 210fmol/ml (range 58-7825 fmol/ml). The levels of bradykinin-(1-5) in ascitic fluid were higher in patients with refractory ascites [median 1091fmol/ml (range 58-7825fmol/ml)] than in patients with responsive ascites [134 fmol/ml (72-1084fmol/ml)] ( P = 0.010). Ascitic fluid levels of bradykinin-(1-9) were not related to the severity of ascites. PRA was higher in patients with refractory ascites [23.0ngċh -1 ċml -1 (7.9-80.0ngċh -1 ċml -1 )] than in patients with responsive ascites [6.9ngċh -1 ċml -1 (0.9-29.4ngċh -1 ċml -1 )] ( P = 0.002). In ascitic fluid, 48% (19-68%) of high- M r kininogen was cleaved, and plasmin-antiplasmin complexes were more concentrated than in plasma ( P = 0.0001). In conclusion, in the ascitic fluid of patients with cirrhosis, both bradykinin-(1-9) and bradykinin-(1-5) are present, with cleavage of high- M r kininogen and activation of fibrinolysis. The highest levels of the long-lived metabolite bradykinin-(1-5) were found in the ascitic fluid of patients with refractory ascites and high PRA. Activation of the kinin system may therefore be involved in decompensating cirrhosis, but a cause-effect relationship remains to be established.

Subtle cardiac abnormalities have been described in patients with cirrhosis. Natriuretic peptide hormones have been reported to be sensitive markers of early cardiac disease. We postulate that plasma levels of N-terminal pro-atrial natriuretic peptide and brain natriuretic peptide could be used as markers of cardiac dysfunction in cirrhosis. The aim of the study was to evaluate the levels of N-terminal pro-atrial natriuretic peptide and brain natriuretic peptide and their relationship with cardiac structure and function in patients with cirrhosis. The study population comprised 36 patients with cirrhosis of mixed aetiologies, but with no cardiac symptoms; 19 of the patients had ascites and 17 did not. The subjects underwent (i) trans-thoracic two-dimensional echocardiography, and (ii) radionuclide angiography for measurements of cardiac structural parameters, diastolic and systolic function. Levels of N-terminal pro-atrial natriuretic peptide and brain natriuretic peptide were also measured. The results were compared with those from eight age- and sex-matched healthy volunteers. Compared with the controls, the baseline mean ejection fraction was increased significantly in both patient groups ( P = 0.02), together with prolonged deceleration times ( P = 0.03), left atrial enlargement ( P = 0.03) and interventricular septal thickening ( P = 0.02), findings that are compatible with diastolic dysfunction. Levels of N-terminal pro-atrial natriuretic peptide and brain natriuretic peptide were significantly higher in all patients with cirrhosis with ascites ( P = 0.01 and P = 0.05 respectively), but in only some of the pre-ascitic cirrhotic patients, compared with controls. All high levels of brain natriuretic peptide were correlated significantly with septal thickness ( P < 0.01), left ventricular diameter at the end of diastole ( P = 0.02) and deceleration time ( P < 0.01). We conclude that elevated levels of brain natriuretic peptide are related to interventricular septal thickness and the impairment of diastolic function in asymptomatic patients with cirrhosis. Levels of brain natriuretic peptide may prove to be useful as a marker for screening patients with cirrhosis for the presence of cirrhotic cardiomyopathy, and thereby identifying such patients for further investigations.

To delineate the clinical roles of plasma cytokine or endotoxin levels in the natural course of infection in patients with decompensated cirrhosis, 66 cirrhotic patients were studied within a 1.5-year period. Plasma levels of tumour necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, IL-8 and endotoxin were determined on days 1, 4 and 7 after admission when hospital infection was suspected and 4 months later. A total of 24 patients (36.4%) were proven to be infected during hospitalization (group A), while 42 others were not infected (group B). Fever occurred in a very high proportion (22/24) of group A patients. Baseline levels of TNF-α (37.7±15.2 compared with 8.7±1.2 pg/ml; P < 0.01) and IL-6 (180.5±20.5 compared with 24.6±7.5 pg/ml; P < 0.0001) were higher in group A patients, while IL-1β, IL-8 and endotoxin levels were not significantly different between the two groups. For patients with hospital infection, IL-6 levels determined during the episode were significantly higher than baseline levels. Using IL-6 > 80 pg/ml as a baseline cut-off level to diagnose bacterial infection, the sensitivity, specificity and accuracy were 87.5, 100 and 95.5% respectively. The one-year cumulative probability of mortality (61.1% compared with 23.7%; P < 0.001) and of bacterial re-infection (72.2% compared with 18.4%; P < 0.0001) was higher in group A than in group B. Plasma TNF-α and IL-6 levels determined at 4 months were not different between the two groups. In conclusion, fever or elevated plasma IL-6 levels in patients with decompensated cirrhosis calls for early antibiotic treatment to prevent life-threatening bacterial infection. Bacterial infection is likely to recur in those patients with increased IL-6 levels, while severe episodes of infection occur in patients with increased TNF-α levels.

In cirrhosis there is a hyperdynamic circulation, which occurs mainly in the systemic and splanchnic regions. Using isolated-vessel models, previous studies have shown reduced aortic reactivity to vasoconstrictors in rats with cirrhosis. The aim of the present study was to evaluate and compare the vascular responsiveness to phenylephrine in arterial rings and the blood flows from different regions in rats with cirrhosis and controls. Reactivity was studied in isolated thoracic aortic, superior mesenteric arterial and carotid arterial rings from sham-operated and bile-duct-ligated rats by measuring the cumulative concentration-dependent tension induced by phenylephrine (10 -9 –10 -4 M). Blood flows were measured by the radioactive microsphere method. In rats with cirrhosis, a significant hyporeactivity to phenylephrine was observed in both the aorta and the superior mesenteric artery compared with the corresponding arteries of normal rats. This hyporesponsiveness was corrected by N ω -nitro- l -arginine (0.1 mM). In contrast, carotid artery reactivity and the responses to N ω -nitro- l -arginine were similar in the cirrhotic and control groups. In each case, cardiac output and mesenteric arterial blood flow were significantly higher in cirrhotic than in normal rats. Cerebral blood flows were not significantly different between the two groups. In cirrhotic rats, arterial hyporeactivity may be a consequence of increased regional blood flow and increased production of nitric oxide.

The aim of this study was to assess the relationship between subtle cardiovascular abnormalities and abnormal sodium handling in cirrhosis. A total of 35 biopsy-proven patients with cirrhosis with or without ascites and 14 age-matched controls underwent two-dimensional echocardiography and radionuclide angiography for assessment of cardiac volumes, structural changes and systolic and diastolic functions under strict metabolic conditions of a sodium intake of 22 mmol/day. Cardiac output, systemic vascular resistance and pressure/volume relationship (an index of cardiac contractility) were calculated. Eight controls and 14 patients with non-ascitic cirrhosis underwent repeat volume measurements and the pressure/volume relationship was re-evaluated after consuming a diet containing 200 mmol of sodium/day for 7 days. Ascitic cirrhotic patients had significant reductions in (i) cardiac pre-load (end diastolic volume 106±9 ml; P < 0.05 compared with controls), due to relatively thicker left ventricular wall and septum ( P < 0.05); (ii) afterload (systemic vascular resistance 992±84 dyn·s·cm -5 ; P < 0.05 compared with controls) due to systemic arterial vasodilatation; and (iii) reversal of the pressure/volume relationship, indicating contractility dysfunction. Increased cardiac output (6.12±0.45 litres/min; P < 0.05 compared with controls) was due to a significantly increased heart rate. Pre-ascitic cirrhotic patients had contractile dysfunction, which was accentuated when challenged with a dietary sodium load, associated with renal sodium retention (urinary sodium excretion 162±12 mmol/day, compared with 197±12 mmol/day in controls; P < 0.05). Cardiac output was maintained, since the pre-load was normal or increased, despite a mild degree of ventricular thickening, indicating some diastolic dysfunction. We conclude that: (i) contractile dysfunction is present in cirrhosis and is aggravated by a sodium load; (ii) an increased pre-load in the pre-ascitic patients compensates for the cardiac dysfunction; and (iii) in ascitic patients, a reduced afterload, manifested as systemic arterial vasodilatation, compensates for a reduced pre-load and contractile dysfunction. Cirrhotic cardiomyopathy may well play a pathogenic role in the complications of cirrhosis.

We investigated the haemodynamic response to volume depletion and subsequent repletion in patients with cirrhosis and portal hypertension. Twelve patients with compensated cirrhosis and portal hypertension were included in the study. The haemodynamic changes occurring after removal of approx. 15% of the blood volume, and subsequently after isovolume repletion with colloid, were assessed. Baseline haemodynamic measurements showed increased cardiac output and a systemic vascular resistance at the lower limit of normal. The hepatic venous pressure gradient (HVPG) was increased, at 18 mmHg. After depletion, arterial pressure, cardiac output and all right-heart-sided pressures decreased, and systemic vascular resistance increased. HVPG decreased to 16.0 mmHg. All the above changes were statistically significant. After blood volume restitution, the haemodynamic values returned to baseline. In particular, an increase in HVPG was shown in four out of the twelve patients (two with ascites and two without), which was small in three of them. However, HVPG remained the same as or lower than the baseline in the other eight patients. Patients with cirrhosis and portal hypertension exhibit an abnormal haemodynamic response to blood volume depletion. After volume repletion, no increase in the portal pressure was noted in this group of patients as a whole, although four out of the twelve patients did show an increase, possibly due to extensive collateral circulation.

Systemic arterial vasodilatation has been implicated in the pathogenesis of sodium retention in cirrhosis. Hydrophobic bile acids, which have vasodilatory actions, may be involved. Ursodeoxycholic acid, a hydrophilic bile acid, could potentially decrease systemic arterial vasodilatation, possibly due to its antioxidant effects, and improve sodium handling in cirrhosis. The effects of ursodeoxycholic acid on systemic, renal and forearm haemodynamics, liver function and renal sodium handling were assessed in vasodilated cirrhotic patients with refractory ascites treated with a transjugular intrahepatic porto-systemic shunt (TIPS). Eight cirrhotic patients with refractory ascites without TIPS placement served as controls for the sodium handling effects of ursodeoxycholic acid. From 1 month post TIPS, seven patients were studied before, after 1 month of treatment with ursodeoxycholic acid (15 mg·day -1 ·kg -1 ) and at 1 month follow-up. Lipid peroxidation products were used as indices of its antioxidant effects. Ursodeoxycholic acid caused a significant reduction in sodium excretion in both groups ( P < 0.05). This, in the post-TIPS patients (urinary sodium excretion: 35±8 mmol/day at 1 month versus 93±21 mmol/day at baseline, P < 0.05), was due to a significant increase in sodium reabsorption proximal to the distal tubule ( P < 0.05), without any significant changes in systemic, renal or forearm haemodynamics, or in liver function. No significant change in lipid peroxidation products was observed. We conclude that: (i) in cirrhotic patients with refractory ascites, ursodeoxycholic acid causes sodium retention, (ii) the abnormality in sodium handling in the post-TIPS cirrhotic patients appears to be the result of a direct effect on the proximal nephron, suggesting that factors other than systemic vasodilatation also contribute to sodium retention in cirrhosis, (iii) caution should be exercised in administering ursodeoxycholic acid in cirrhotic patients with ascites.

1. Impaired vasoconstriction in animals with cirrhosis is maintained in isolated vessels in vitro , indicating an intrinsic alteration in function or structure of the cells in the vascular wall. This may be due to receptor down-regulation, a defect in post-receptor signal transduction or overproduction of vasodilator compounds. This investigation examined the role of these mechanisms in modulating α-adrenoceptor-mediated contraction in hepatic arteries from patients with advanced cirrhosis. 2. Hepatic arteries were obtained from subjects with and without cirrhosis for functional investigation in vitro . Endothelial cell function was assessed using endothelium-dependent (acetylcholine) and independent (3′-morpholinosydnonimine) vasodilators. α-Adrenoceptor-mediated contraction was assessed by constructing cumulative concentration–response curves to the α 1 -selective agonist phenylephrine, the non-selective adrenoceptor agonist noradrenaline and the receptor-independent vasoconstrictor potassium chloride. 3. None of the vessels used in this study had an intact endothelium but endothelium-independent relaxation was not different in arteries from subject with (79.5±10.16%; n = 23) and without (84.45±18%; n = 20) cirrhosis. Phenylephrine, noradrenaline and potassium chloride produced contractions that were of similar size ( P > 0.05) in arteries from subjects with (10.10±0.97 ;g, 8.85±1.03 ;g and 8.56±0.65 ;g respectively) and without (10.42±1.23 ;g, 9.58±1.39 ;g and 8.62±0.98 ;g respectively) cirrhosis. The sensitivities (pD 2 ) of the responses to these agonists were also similar ( P < 0.05) in arteries from patients with cirrhosis (5.45±0.10, 5.60±0.12 and 1.57±0.03 respectively) and those from non-cirrhotic donors (5.58±0.11, 5.67±0.11 and 1.54±0.05 respectively). 4. Contraction of the denuded hepatic artery was unaffected by cirrhosis indicating that vascular abnormalities in this condition in man are not due to an intrinsic alteration of smooth muscle cell function in hepatic conduit arteries.

1. Portal hypertension and hyperdynamic circulation have been postulated to play a role in the pathogenesis of portal hypertensive gastropathy. Administration of octreotide to portal hypertensive rats has been shown to reduce portal pressure and ameliorate hyperdynamic circulation. 2. This study investigated the effects of chronic administration of octreotide on systemic and portal haemodynamics and the development of portal hypertensive gastropathy in carbon tetrachloride-induced cirrhotic rats. 3. After 12 weeks of carbon tetrachloride induction, cirrhotic rats were randomly assigned to receive either placebo (5% dextrose in water) or octreotide (65 μg/kg in 5% dextrose in water) subcutaneously twice daily for 10 days. Haemodynamic studies with a thermodilution technique and gastric morphometric analyses were performed at 10 days after treatment. 4. In cirrhotic rats, octreotide treatment induced a significant increase in systemic vascular resistance (2.7 ± 0.2 versus 3.4 ± 0.2 mmHg/ml · min −1 · 100 g −1 , P < 0.05) and decrease in portal pressure (12.5 ± 1.2 versus 9.9 · 0.5 mmHg, P < 0.05) compared with placebo-treated rats. In addition, octreotide treatment significantly reduced the mean cross-sectional area of gastric mucosal vessels (2290 ± 145 versus 1810 ± 101 μm 2 , P < 0.05). 5. This study shows that chronic octreotide treatment ameliorates the development of portal hypertensive gastropathy in cirrhotic rats. The effect of octreotide on portal hypertensive gastropathy may, at least partly, be due to the alleviation of portal hypertension and hyperdynamic circulation.

1. Hyperdynamic circulation observed in portal hypertensive states is characterized by generalized vasodilatation, increased cardiac index and increased systemic and regional blood flows. Endotoxin, tumour necrosis factor-alpha (TNF-α) and nitric oxide (NO) have been reported to be involved in the pathogenesis of hyperdynamic circulation, but the interactions between endotoxin, TNF-α and NO in cirrhotic rats with ascites have never been specifically addressed. 2. This study was designed to determine systemic and portal haemodynamics and plasma levels of endotoxin, TNF-α and nitrate/nitrite in cirrhotic rats with ascites and investigate the relationships between these substances. 3. Plasma concentrations of endotoxin, TNF-α and nitrate/nitrite (an index of NO production) were determined in 25 cirrhotic rats with ascites and 17 control rats using the Limulus assay, ELISA and a colorimetric assay respectively. In addition, haemodynamic studies were performed in another ten cirrhotic rats with ascites and ten control rats. 4. Cirrhotic rats with ascites had hyperdynamic circulation accompanied by increased plasma levels of endotoxin, TNF-α and nitrate/nitrite, as compared with control rats. Significant correlation existed between plasma levels of endotoxin and nitrate/nitrite ( r = 0.59, P < 0.0001) and between plasma levels of endotoxin and TNF-α ( r = 0.63, P < 0.0001). No correlation was detected between plasma levels of TNF-α and nitrate/nitrite ( r = 0.24, P > 0.05). 5. This study suggests that endotoxaemia developed in cirrhotic rats with ascites may stimulate NO formation directly or indirectly via cytokine cascade, and consequently participate in the development and/or maintenance of hyperdynamic circulation.

1. The hepatorenal syndrome is the development of renal failure in patients with severe liver disease in the absence of any identifiable renal pathology. 2. Decreased glomerular filtration is caused by a reduction in both renal blood flow and the renal filtration fraction. These changes arise as a consequence of a fall in mean arterial pressure due to systemic vasodilatation, activation of the sympathetic nervous system causing renal vasoconstriction, and increased synthesis of several vasoactive mediators, which together modulate both renal blood flow and the glomerular capillary ultrafiltration coefficient, and thence filtration fraction. 3. Patients with liver disease developing renal failure should have hypovolaemia excluded by volume challenge, and all nephrotoxic drugs including diuretics should be stopped. Broad-spectrum antibiotics should be given for subclinical infection, which may be a treatable precipitant of renal failure in cirrhosis. Renal perfusion should be optimized by ensuring that the blood pressure and systemic haemodynamics are adequate, and that if renal venous pressure is elevated, due to tense ascites, it is alleviated. 4. The prognosis of hepatorenal syndrome is poor with a >90% mortality. However, patients can and do recover from the hepatorenal syndrome, but only if there is a significant improvement of their liver function, or if they undergo liver transplantation.

1. Adrenomedullin is a potent vasodilating peptide first isolated from phaeochromocytoma and adrenal medulla but also found in the heart, lungs and kidneys. It may also be a paracrine factor because endothelial and smooth muscle cells synthesize adrenomedullin as well as express the receptors. Adrenomedullin induces vasorelaxation by activating adenylate cyclase and also by stimulating the release of nitric oxide. 2. We have developed a specific radioimmunoassay and measured the immunoreactivity of human adrenomedullin in the plasma of 58 male subjects: eight with essential hypertension, 12 with heart failure, 10 with ascites due to cirrhosis, 12 with chronic renal failure, four with hypoxia due to chronic obstructive pulmonary disease and 12 control subjects. 3. Plasma levels (mean ± SEM) in patients with essential hypertension (16.3 ± 1.9 pmol/l), congestive heart failure (17.5 ± 2.8 pmol/l) and renal failure (17.7 ± 2.5 pmol/l) were raised compared with control subjects (7.8 ± 1.4 pmol/l, P < 0.05), confirming previous reports. 4. In addition, we observed that plasma levels of adrenomedullin were significantly raised in patients with ascites due to liver cirrhosis (15.5 ± 1.9 pmol/l) and chronic obstructive pulmonary disease with hypoxia (20.0 ± 1.5 pmol/l). 5. We concluded that the plasma level of adrenomedullin is raised in a variety of diseases.

1. Although pentoxifylline has been shown to reduce portal hypertension, the mechanism for this is unclear. Since pentoxifylline decreases tumour necrosis factor-α production and since this cytokine may induce vasodilatation per se , a pentoxifylline-induced decrease in tumour necrosis factor-α production may limit arterial vasodilatation and decrease portal pressure. The aim of the present study was to examine the effects of pentoxifylline administration on plasma tumour necrosis factor-α concentrations and haemodynamics in normal and cirrhotic rats. 2. In both groups, systemic and splanchnic haemodynamics and plasma tumour necrosis factor-α concentrations were measured before and 120 min after the administration of saline or pentoxifylline (20 mg/kg intravenous bolus). 3. In cirrhotic rats, pentoxifylline significantly decreased portal pressure (24 ± 13%) and tributary blood flow (33 ± 30%). On the other hand, pentoxifylline significantly increased vascular resistance in portal and hepatic arterial territories. Systemic haemodynamics were not altered. In normal rats, pentoxifylline significantly decreased portal pressure but induced no other significant changes in splanchnic or systemic haemodynamics. In cirrhotic rats, plasma tumour necrosis factor-α concentrations were significantly reduced after pentoxifylline administration but not after saline administration. No significant correlations were found between pentoxifylline-induced changes in tumour necrosis factor-α levels and changes in splanchnic haemodynamics. In normal rats, plasma tumour necrosis factor-α concentrations significantly decreased after pentoxifylline or saline administration. 4. This study shows that in rats with cirrhosis, pentoxifylline induces a decrease in both portal pressure and plasma tumour necrosis factor-α concentrations. These reductions were not correlated however.

1. There is currently considerable interest in the role of locally produced vasodilators such as nitric oxide and adenosine in the pathogenesis of the peripheral vasodilatation of cirrhosis. However, the signal transduction pathways involving guanylate cyclase and adenylate cyclase have not been clearly delineated in the isolated blood vessel. 2. We therefore aimed to examine the in vitro vasorelaxant effects of the endothelium-dependent dilator bethanechol, the endothelium-independent dilator sodium nitroprusside and adenosine, as drugs that work via activation of guanylate and adenylate cyclases, in isolated aortic and superior mesenteric arterial rings from cirrhotic and control rats. 3. Cirrhosis was induced by chronic bile duct ligation and section of 24–28 days' duration, while controls underwent sham operation. The vessels were precontracted with the α 1 -adrenoceptor agonist phenylephrine, then relaxed by incremental doses of the three drugs. 4. Marked attenuation of vasoconstriction induced by phenylephrine in isolated aortic and mesenteric arterial rings from cirrhotic rats compared with the control vessels was observed. 5. There were no significant differences in relaxation between the cirrhotic and control vessels to the three drugs. We conclude that in vitro vasodilatory responses mediated through signal transduction pathways involving guanylate cyclase and adenylate cyclase remain unchanged in a rat model of biliary cirrhosis.

1. Previous studies have documented activation of protease enzymes, such as the plasma kallikrein-kinin system, in hepatic cirrhosis. Increased plasma kinin generation could contribute to pathological systemic vasodilatation in cirrhosis, and reduced systemic vascular resistance has been suggested as a trigger to renal sodium retention in this disease. We investigated the effect of aprotinin, a protease inhibitor which binds to plasma kallikrein, on systemic haemodynamics and renal function in patients with hepatic cirrhosis and ascites. 2. Aprotinin was infused intravenously in high dosage (2 × 10 6 kallikrein inhibitory units loading, 1 × 10 6 kallikrein inhibitory units/h). 3. Of 13 patients, 10 had a low systemic vascular resistance (< 1200 dyn s cm −5 ) at baseline. In this group, eight showed an increase in systemic vascular resistance during aprotinin infusion. Overall, the increase in systemic vascular resistance was significant, and there was a small but significant increase in mean arterial pressure. In all patients, there were increases in renal plasma flow, glomerular filtration rate, and absolute and fractional urinary sodium excretion during aprotinin infusion. 4. Plasma renin activity, plasma angiotensin II and plasma aldosterone fell significantly during aprotinin infusion. Plasma prekallikrein, plasma noradrenaline and plasma atrial natriuretic peptide did not change. Plasma aprotinin concentration was 209 ± 11 kallikrein inhibitory units/ml at the end of the infusion. 5. Before and during the infusion, there was a significant negative correlation between systemic vascular resistance and plasma renin activity. There was a positive correlation between the change in systemic vascular resistance and the change in renal plasma flow during aprotinin infusion. 6. In patients with hepatic cirrhosis and ascites, treatment with aprotinin appears beneficial in relation to systemic and renal haemodynamics, sodium excretion and hormonal stimulation, with no evidence of adverse effects. The results are compatible with an association between plasma kallikrein-kinin activation, systemic vasodilatation, renin-angiotensin activation, and renal vasoconstriction and sodium retention in this condition.

1. Fasting levels of plasma cysteine, plasma sulphate and the plasma cysteine/sulphate ratio were measured in patients with primary biliary cirrhosis and compared with those in patients with other liver disease, general intensive therapy unit patients and healthy subjects. 2. Plasma cysteine was significantly elevated in patients with primary biliary cirrhosis (median 0.364 nmol/mg of protein, P < 0.0001) and patients with other liver disease (median 0.445 nmol/mg of protein, P < 0.0001), compared with healthy control subjects (median 0.125 nmol/mg of protein) and increased progressively with the severity of liver disease. Plasma cysteine was also elevated in intensive therapy unit patients (median 1.564 nmol/mg of protein) compared with healthy control subjects ( P < 0.0001) and patients with other liver disease ( P < 0.0001). 3. Plasma sulphate was reduced significantly only in patients with primary biliary cirrhosis (median 0.822 nmol/mg of protein) compared with healthy control subjects (median 1.37 nmol/mg of protein, P < 0.05). There was no significant difference in plasma sulphate between disease groups. 4. The plasma cysteine/sulphate ratio was significantly elevated in patients with primary biliary cirrhosis (median 0.448, P < 0.0001) and patients with other liver diseases (median 0.394, P < 0.0001) compared with healthy control subjects (median 0.095). The ratio was also elevated in intensive therapy unit patients (median 1.650, P < 0.0001) compared with healthy control subjects and liver disease groups ( P < 0.0001). 5. In conclusion, plasma cysteine rises in primary biliary cirrhosis and other forms of liver disease. This effect is not specific to liver disease, since cysteine is elevated in an heterogeneous group receiving intensive care. Impairment of trans -methylation and trans -sulphuration pathways does not explain the finding of increased plasma cysteine. Since cysteine is elevated in non-hepatic disease, it may reflect the effect of muscle breakdown and the catabolic state. Impaired activity of cysteine dioxygenase and impaired mitochondrial function may be contributory, but this requires further study. These metabolic changes may reflect progressively diminished detoxification capacity within the liver and other tissues.

1. The Z deficiency variant of α 1 -antitrypsin predisposes the homozygote to early-onset panlobular emphysema and results in the accumulation of antitrypsin within the hepatocyte, which leads to hepatocellular damage and cirrhosis. The mechanism of this accumulation has been shown to be due to the Z mutation (Glu-342→Lys) perturbing the structure of the protein, allowing a unique interaction between the reactive-centre loop of one molecule and the A sheet of a second. This loop—sheet polymerization occurs spontaneously at 37°C in purified plasma Z but not M antitrypsin. The rate of polymerization is greatly accelerated at 41 C and is blocked by the insertion of a specific peptide into the A sheet of the antitrypsin molecule. Electron microscopy and circular dichroic spectral analysis confirm that the Z antitrypsin polymers formed in vitro have structural identity with those isolated from the liver of a Z homozygote. 2. That loop—sheet polymerization is a more general phenomenon was shown by the examination of a second deficiency variant, antitrypsin S iiyama (Ser-53→Phe), which is also associated with liver inclusions. Electron microscopy confirmed that isolated antitrypsin S iiyama from the plasma of a homozygote was present as long chains of polymers identical with those of Z antitrypsin.

1. We report the first demonstration of the pathophysiological importance and clinical applications of the relatively recently discovered circulating enzyme, phosphoinositol-specific phospholipase D. This enzyme is known to cleave the large variety of important cell-surface molecules linked to the cell membrane by glycan-phosphatidylinositol linkages (glycan-phosphatidylinositol anchors). 2. When measured in the sera of healthy individuals, phosphoinositol-specific phospholipase D activity was found to show a strong negative correlation with age, the degree of depreciation being greater than that measured for most other analytes. 3. Serum phosphoinositol-specific phospholipase D activity was considerably depressed in patients presenting with conditions leading to reduced liver synthetic reserve, such as hepatocellular carcinoma or liver cirrhosis caused by chronic viral hepatitis, and correlated with reduced albumin levels in these conditions, indicating that the liver is the site of phosphoinositol-specific phospholipase D synthesis and that phosphoinositol-specific phospholipase D may be used as an additional marker of liver synthetic reserve. 4. When measured in patients with acute liver disease, such as acute viral hepatitis, or in patients with bronchopneumonia, phosphoinositol-specific phospholipase D activity was found to be significantly raised, demonstrating features characteristic of an acute-phase reactant. 5. These findings indicate that, besides its pathophysiological importance, phosphoinositol-specific phospholipase D and the measurement of its activity in serum may have a useful place in the investigation of a range of clinical conditions, including tissue injury and inflammation.

1. Nitric oxide (NO) is a potent endogenous vasodilator and plays a role in the control of resting vascular tone. Patients with cirrhosis have a hyperdynamic circulation with reduced blood pressure and decreased peripheral resistance, and it is possible that increased production of NO due to induction of NO synthase may be involved in maintaining this vasodilatation. We have examined this possibility by studying the effects of local infusions of N G -monomethyl-l-arginine (an inhibitor of NO synthase) in the forearm arteriolar bed and the superficial dorsal hand veins of patients with alcoholic cirrhosis. 2. Drugs were either infused locally into the brachial artery and forearm blood flow was measured by venous occlusion plethysmography, or into a vein on the back of the hand and vein diameter was measured using a linear displacement technique. 3. Basal forearm blood flow was increased and vascular resistance was decreased in the patients with alcoholic cirrhosis compared with healthy control subjects. Noradrenaline and N G -monomethyl-l-arginine caused dose-dependent falls in forearm blood flow in both healthy control subjects and patients with cirrhosis. There was no significant difference in the responses to either noradrenaline or N G -monomethyl-l-arginine between the two groups. 4. In the superficial hand veins there was no change in vein size in response to N G -monomethyl-l-arginine infused alone, and venoconstriction to local infusion of noradrenaline was unaffected by co-infusion with N G -monomethyl-l-arginine. 5. Our results confirm that patients with alcoholic cirrhosis are vasodilated compared with healthy control subjects. Our findings show that basal NO-mediated vasodilatation occurs in the forearm arterial bed, but not the superficial hand veins, of these patients. However, since the response to local NO synthesis inhibition was similiar in the two groups, increased production of NO due to induction of NO synthase is unlikely to account fully for the vasodilatation seen in patients with mild to moderate alcoholic cirrhosis.

1. Decreased pressor sensitivity to angiotensin II occurs in cirrhosis, but the mechanism remains unclear. 2. Angiotensin II dose-response studies were performed in conscious, chronically instrumented cirrhotic and control rats, and angiotensin II concentration-response studies were performed in isolated blood vessels obtained from similar groups of animals. 3. Cirrhotic rats demonstrated a significantly decreased pressor response to angiotensin II (5-80 ng/kg intravenously). However, angiotensin II-generated tension in thoracic aortic rings isolated from cirrhotic rats and studied in vitro was not impaired. These findings are consistent with the concept that circulating vasodilator substances in cirrhosis rather than an abnormality intrinsic to vascular smooth muscle cells are responsible for the decreased pressor sensitivity to angiotensin II in vivo. 4. Pretreatment with the cyclo-oxygenase inhibitor indomethacin (3 mg/kg intravenously) restored pressor sensitivity to angiotensin II to normal, suggesting that cyclo-oxygenase products, possibily vasodilator prostaglandins, may be involved in mediating pressor resistance to this hormone in vivo.

1. Isolated perfused cirrhotic rat livers were used to study the effects of an increase in portal perfusion pressure and portal flow on the microcirculation and viability of the hepatocytes. Cirrhosis was induced by CCl 4 , and Krebs-Ringer bicarbonate buffer solution was used as the perfusate. Portal perfusion pressures were increased incrementally between 25 and 45 cm H 2 O. The viability of the livers was assessed and histological studies were performed under light and electron microscopy. 2. An increase in portal perfusion pressure induced an increase in hepatic flow in all the experiments ( P < 0.05). Hepatic flow was 2.52 ml min −1 g −1 of liver (SD 0.67; n = 5) at basal pressure compared with 4.19 ml min −1 g −1 of liver (SD 0.93; n = 5) and 5.91 ml min −1 g −1 of liver (SD 0.63; n = 5) when pressures were raised to 25 and 45 cm H z O, respectively. Portal perfusion pressure and hepatic flow were correlated ( r = 0.908; P < 0.001; n = 30). 3. Production of the enzyme alanine aminotransferase (EC 2.6.1.2) increased significantly from 5.69 i.u. ml −1 min g -l of liver (SD 3.62; n = 5) to 23.53 i.u. ml −1 min g −1 of liver (SD 16.7; n = 5) when the perfusion pressure was raised from baseline to 30 cm H 2 O. In all the cases the porto-caval gradient of enzyme production was within the normal range. No correlation existed between the release of enzyme and portal perfusion pressures 4. Histological studies demonstrated sinusoidal dilatation in one case out of five in the control group compared with nine cases out of 25 in the high perfusion pressure groups. Dead sinusoidal cells coloured by Trypan Blue were observed in one case out of five in the control group compared with nine cases out of 25 in the high perfusion pressure groups. With electron microscopy, occasional lesions such as detachment of endothelial cells or blebs were found. No relationship existed between portal perfusion pressures and histological lesions. 5. This study shows that a brief increase in portal perfusion pressure in the isolated perfused cirrhotic rat liver induces an increase in hepatic flow without a change in the viability of the liver and without significant histological alterations.

1. To examine the contributions of hypersecretion and decreased insulin clearance to the hyperinsulinaemia of cirrhosis, insulin secretion was calculated over the day from serum C-peptide concentrations and C-peptide metabolic clearance rate. The latter was measured during infusions of recombinant human C-peptide. In cirrhotic patients (n = 9) insulin secretion rate was twice that of normal control subjects ( n = 10), both in the basal state [02.00–07.00 hours, 15.7 ± 2.1 (mean ± sem ) nmol/h (2.6 ± 0.4 units/h) versus 7.0 ± 0.9 nmol/h (1.2 ± 0.2 units/h), P <0.002] and over 24 h [787 ± 93 nmol (132 ± 16 units) versus 346 ± 34 nmol (58 ± 6 units), P< 0.001]. However, the area under the serum insulin concentration curve was approximately six times greater in the cirrhotic patients (24 h basal, 6.3 ± 1.0 versus 1.1 ± 0.31 nmol l −1 h, P< 0.001; 24 h total, 21.7 ± 3.2 versus 3.7 ± 0.7 nmol l −1 h, P< 0.001). Thus, despite impairment of insulin clearance there is continuing hyper-section of insulin in cirrhosis. 2. The relationship of carbohydrate and lipid metabolism with insulin secretion was assessed. In cirrhotic patients, 24 h blood glucose profiles showed a worsening of glucose tolerance over breakfast, despite greater insulin secretion compared with other meals, suggesting that the insulin insensitivity of cirrhosis is worse at this time. 3. Cirrhotic patients showed impaired suppression of blood glycerol levels after meals but normal suppression of serum non-esterified fatty acid concentrations. The greatest differences in the profiles of serum lipids and lipid-related metabolites in cirrhotic patients and control subjects occurred at night. Whereas in control subjects, serum non-esterified fatty acid, blood glycerol and blood 3-hydroxybutyrate concentrations peaked between 01.00 and 03.00 hours, falling gradually thereafter until 08.00 hours, in cirrhotic patients serum non-esterified fatty acid and blood glycerol levels showed a gradual increase during the night to reach maximal levels at 08.00 hours when they were twice those of control subjects (P< 0.001). 4. The blood 3-hydroxybutyrate and serum triacyl-glycerol profiles suggested that in cirrhotic patients there was preferential utilization of non-esterified fatty acids for ketogenesis and reduced re-esterification to triacylglycerol.

1. The systemic and splanchnic haemodynamic effects of pentifylline (40 mg/kg body weight intravenously) were assessed in rats with portal hypertension associated either with CCl 4 -induced cirrhosis ( n = 13) or portal vein ligation ( n =13). 2. Heparinized catheters were placed into the portal vein, inferior vena cava, aorta and left ventricle with exits from the neck. Haemodynamic studies were performed 4 h after consciousness was regained. Cardiac output and regional blood flows were measured using radiolabelled microspheres and the reference sample method in seven rats in each group; portal-systemic shunting was measured using microsphere injection in the ileo-colic vein in six rats in each group. 3. Forty-five minutes after injection, pentifylline had no effect on mean arterial pressure, cardiac output, peripheral resistance, portal venous flow, hepatic artery flow or portal-systemic shunting in either group of rats with portal hypertension. The drug lowered portal pressure (−18%) in cirrhotic rats, but not in portal-vein-ligated rats. 4. These data demonstrate that pentifylline lowers portal pressure in cirrhotic rats without affecting portal venous flow and portal-systemic shunting; this effect is possibly mediated by changes in intrahepatic resistance related to the effects of pentifylline on blood viscosity and/or on intrahepatic vasomotor tone.

1. Systemic hypotension, blunted cardiovascular responsiveness to noradrenaline and an abnormal hypertensive pressor response to a postural change have been described in cirrhotic patients. 2. We have examined the role of blunted responsiveness in these abnormalities by studying basal arterial blood pressure and its response to a postural change (vertical head-up 90° tilting) in conscious and pithed CCl 4 -treated (cirrhotic) rats, as well as assessing the pressor response to noradrenaline in vivo and the vascular contractile response to noradrenaline in vitro. 3. A diminished hypotensive response to a change in posture was found in pre-cirrhotic portal hypertensive rats, whereas an inverted hypertensive pressor response in the face of systemic hypotension occurred in the cirrhotic rats with portal hypertension. 4. The inverted pressor response was abolished in the pithed portal hypertensive cirrhotic rats. 5. The pressor response to noradrenaline in vivo in conscious cirrhotic rats and the vascular contractile responsiveness to noradrenaline in vitro were intact. 6. We conclude that blunted responsiveness to noradrenaline is not a contributory factor to the development of systemic hypotension or the inverted pressor response to a change in posture in cirrhosis.

1. To assess the value of serum α- l -fucosidase (EC 3.2.1.51) as a marker for hepatocellular carcinoma, the activity was measured in patients with hepatocellular carcinoma and in control subjects. 2. Mean serum α- l -fucosidase activity was significantly greater in 35 patients with hepatocellular carcinoma (225 ± 69 nkat/l) than in 35 patients with cirrhosis and 20 normal subjects (134 ± 30 and 93 ± 28 nkat/l, respectively). The overlap between hepatocellular carcinoma and cirrhosis, however, was such as to severely limit any value of the enzyme as a diagnostic test. 3. In four cirrhotic patients with hepatocellular carcinoma, an increased enzyme activity was detectable in samples taken up to 66 months before the tumours were diagnosed clinically. 4. The serum activity of α- l -fucosidase fell to within the reference range after liver transplantation for hepatocellular carcinoma in three patients and in one of these a subsequent rise was associated with tumour recurrence which was diagnosed at 8 months after the rise in activity. Ineffective cytotoxic chemotherapy was also associated with a progressive rise in serum α- l -fucosidase activity. 5. α- l -fucosidase activity in tumour tissue was significantly lower than that seen in non-tumour tissue from cirrhotic patients. These reductions may represent increased transport from the tissue and may partly account for the increased serum activity found in some patients with hepatocellular carcinoma.

1. The effects of angiotensin II on glomerular filtration rate and renal plasma flow were studied in surgically instrumented conscious control and cirrhotic rats. In addition, angiotensin II binding and the contractile response to angiotensin II were studied in glomeruli isolated from cirrhotic and control rats. 2. Cirrhotic rats had a higher glomerular filtration rate and a higher renal plasma flow than control animals. A non-pressor dose of angiotensin II induced small but significant decreases in glomerular filtration rate and renal plasma flow in both control and cirrhotic rats, the effect on renal plasma flow being the most pronounced. 3. Plasma renin and aldosterone concentrations were similar in control and cirrhotic rats. 4. The cross-sectional area of glomeruli from cirrhotic rats was 42% greater than that of glomeruli from control animals. Angiotensin II (10 −9 mol/l) decreased the cross-sectional area of glomeruli from control animals by 6.4 ± 0.9% and of glomeruli from cirrhotic rats by 6.6 ± 0.8% ( P = not significant for comparison between control and cirrhotic animals). 5. There were no differences between control and cirrhotic rats in the affinity of angiotensin II for its glomerular receptors. However, the angiotensin II receptor density was higher in cirrhotic than in control rats, thereby producing an increased total angiotensin II binding in cirrhotic rats. 6. Since no functional differences between control and cirrhotic animals were present in the response to angiotensin II, even though angiotensin II binding was increased, a post-receptor blockade of the angiotensin II signal could be present in cirrhotic rats.