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Background & Aims: Splanchnic vascular hypocontractility with subsequent increased portal venous inflow leads to portal hypertension. Although the renin-angiotensin system contributes to fibrogenesis and increased hepatic resistance in patients with cirrhosis, little is known about its effects in the splanchnic vasculature, particularly those of the alternate system in which angiotensin (Ang) II is cleaved by the Ang-converting enzyme-2 (ACE2) to Ang-(1-7), which activates the G-protein-coupled Mas receptor (MasR). We investigated whether this system contributes to splanchnic vasodilatation and portal hypertension in cirrhosis., Methods: We measured levels of renin-angiotensin system messenger RNA and proteins in splanchnic vessels from patients and rats with cirrhosis. Production of Ang-(1-7) and splanchnic vascular reactivity to Ang-(1-7) was measured in perfused mesenteric vascular beds from rats after bile-duct ligation. Ang-(1-7) and MasR were blocked in rats with cirrhosis to examine splanchnic vascular hemodynamics and portal pressure response., Results: Levels of ACE2 and MasR were increased in splanchnic vessels from cirrhotic patients and rats compared with healthy controls. We also observed an ACE2-dependent increase in Ang-(1-7) production. Ang-(1-7) mediated splanchnic vascular hypocontractility in ex vivo splanchnic vessels from rats with cirrhosis (but not control rats) via MasR stimulation. Identical effects were observed in the splanchnic circulation in vivo. MasR blockade reduced portal pressure, indicating that activation of this receptor in splanchnic vasculature promotes portal inflow to contribute to development of portal hypertension. In addition, the splanchnic effects of MasR required nitric oxide. Interestingly, Ang-(1-7) also decreased hepatic resistance., Conclusions: In the splanchnic vessels of patients and rats with cirrhosis, increased levels of ACE2 appear to increase production of Ang-(1-7), which leads to activation of MasR and splanchnic vasodilatation in rats. This mechanism could cause vascular hypocontractility in patients with cirrhosis, and might be a therapeutic target for portal hypertension., (Copyright © 2013 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Background & Aims: Although interleukin 28B (interferon, lambda 3) (IL28B) genotype affects the response of patients with chronic hepatitis C to peginterferon and ribavirin, little is known regarding its effect on response to direct-acting antivirals in interferon-free combinations. We analyzed the effects of IL28B genotype on the viral kinetic (VK) response to an interferon-free combination of the nucleoside polymerase inhibitor mericitabine (RG7128) and the hepatitis C virus (HCV) protease inhibitor danoprevir., Methods: We performed a double-blind, dose-escalation study of patients with chronic HCV genotype 1 infection who were interferon treatment naive or had not responded to previous therapy with peginterferon and ribavirin. Patients were sequentially assigned to 1 of 7 cohorts then randomly assigned to groups that received up to 13 days of treatment with mericitabine (500 or 1000 mg, twice daily) plus danoprevir (100 or 200 mg, every 8 hours, or 600 or 900 mg, twice daily) or placebo. Eighty-three of 87 patients were genotyped for the IL28B single-nucleotide polymorphism rs12979860. VKs were analyzed only in patients who received 13 days of treatment, at optimal doses, using a biphasic model to describe first- and second-phase slopes of viral decay during therapy., Results: At day 14 (the end of interferon-free treatment), the mean reduction in the serum level of HCV RNA was slightly greater in patients with the CC polymorphism (5.01 log(10) IU/mL) than those without (4.59 log(10) IU/mL). Modeling revealed that patients with the CC polymorphism had slightly better early VKs, most apparent in the β-phase of viral decay. A mixed effect on the α-phase was observed, which was reduced in magnitude but prolonged in patients with CC, who also had better on-treatment response to peginterferon and ribavirin during follow up., Conclusions: IL28B genotype appears to affect early VKs in patients with chronic hepatitis C receiving interferon-free treatment., (Copyright © 2012 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Background and Aims: High-dose intravenous hepatitis B immunoglobulin (HBIG) may prevent recurrent hepatitis B virus (HBV) infection, but the cost has limited its widespread use in countries with endemic HBV infection. We report on long-term safety and efficacy of an alternative strategy of very low doses (400-800 IU/month) of intramuscular (IM) HBIG plus lamivudine., Methods: Australian and New Zealand patients who received low-dose HBIG plus lamivudine following liver transplantation for HBV-related end-stage liver disease were studied. Prior to transplantation, patients with detectable serum HBV DNA received lamivudine 100 mg daily. Posttransplantation, all patients received lamivudine 100 mg daily plus IM HBIG 400 or 800 IU daily for 1 week then monthly thereafter. Serum HBV DNA levels were measured prior to lamivudine, at transplantation, and at 12 months posttransplantation. Serum titers of antibody to HBV surface antigen were measured at 1, 3, and 12 months posttransplantation., Results: Between February 1996 and October 2004, 147 patients received low-dose HBIG plus lamivudine. Thirty-one percent were hepatitis B e antigen positive, and 85% were HBV DNA+ prior to transplantation. The median duration of pretransplantation lamivudine was 92 days (range, 1-1775). Median follow-up posttransplantation was 1860 days. Kaplan-Meier patient survival was 92% at 1 year and 88% at 5 years. The actuarial risk of HBV recurrence was 1% at 1 year and 4% at 5 years. Baseline HBV DNA titer was associated with HBV recurrence., Conclusion: Low-dose IM HBIG plus lamivudine provides safe and effective long-term prophylaxis against recurrent HBV at <10% the cost of the high-dose regimen.

Background & Aims: The prevalence of primary biliary cirrhosis (PBC) reported in different countries varies widely, indicating that genetic or environmental factors may be important in the etiology of the disease. The aim of this study was to examine this issue further by determining the overall prevalence of PBC in one state in Australia and to examine the prevalence among different migrant groups within this population., Methods: Thorough case-finding methods were used to identify all cases of PBC in Victoria, Australia. Age-adjusted prevalence rates among different migrant groups were examined., Results: A total of 249 cases were identified, giving a prevalence of 51 cases per million. This is significantly higher than the rate documented in a 1991 Victorian study. Prevalence in the 3 largest migrant groups was greater than that of Victoria as a whole (141, 200, and 208 cases per million in British, Italian, and Greek migrants, respectively). In women older than 40 years, previous studies have documented a prevalence of 940 cases per million in women in the United Kingdom; however, the prevalence was 344 cases per million in British-born immigrants to Victoria and 160 cases per million in Australian-born women., Conclusions: The current prevalence of PBC in Victoria is higher than previously reported, but the age-adjusted prevalence in those born in Victoria remains significantly lower than in the United Kingdom and is less than in migrant communities. These findings suggest that Victorians may be relatively protected from developing the disease and add further weight to the suggestion that environmental factors may play a role in the etiology of PBC.

Background & Aims: Angiotensin II (ANG II) has profibrotic actions in the heart and kidney, whereas blockade of the renin angiotensin system (RAS) attenuates injury. This study examines whether the RAS is present in the liver and examines its regulation in the bile duct-ligation model of hepatic fibrogenesis., Methods: Sham-operated and bile duct-ligated (BDL) Sprague-Dawley rats were studied. Gene and protein expression of hepatic renin, angiotensinogen, angiotensin-converting enzyme (ACE), and the angiotensin receptors AT1 and AT2 were assessed using real-time reverse-transcription polymerase chain reaction, in vitro autoradiography, and immunohistochemistry., Results: Angiotensinogen and renin messenger RNA were detected in sham liver but were not increased following BDL. Angiotensinogen protein was widely distributed in hepatocytes in both normal and injured livers, but in BDL livers, it was also expressed within areas of active fibrogenesis. Both ACE and AT1 receptor genes were up-regulated following BDL. The low level of ACE activity in sham animals was significantly increased in areas of active fibrogenesis in BDL livers. The AT1 receptor was present in both normal and diseased liver parenchyma, with increased AT1 receptor binding seen in fibrotic areas in the diseased liver. The AT2 receptor gene was not detected in normal or diseased liver., Conclusions: Key elements of the RAS are present in normal liver tissue, and there is major up-regulation of the system in the bile duct-ligated liver. These findings are in keeping with recent experimental studies that have demonstrated antifibrotic effects of RAS blockade in the bile duct-ligated liver.

Background & Aims: Sinusoidal capillarization in cirrhosis may impair the transfer of oxygen into hepatocytes; this may contribute to impaired oxidative drug metabolism. The aim of this study was to test this hypothesis by comparing the effects of oxygen supplementation in cirrhotic patients on the clearance of theophylline, which is dependent on hepatic oxidative metabolism, with its effect on the clearance of acetaminophen, which is reliant on hepatic conjugation reactions., Methods: Ten cirrhotic patients awaiting liver transplant and 5 control subjects were studied. Oral acetaminophen (1000 mg) and intravenous theophylline (3 mg/kg) were administered simultaneously on two separate occasions, 7 days apart. Subjects were randomized to breathe either room air or oxygen via face mask at 12 L/min for 9 hours of blood sampling., Results: Theophylline and acetaminophen clearances were significantly reduced by a mean of 54% and 50%, respectively, in cirrhotic patients compared with controls. Oxygen supplementation improved plasma theophylline clearance in cirrhotic patients by a mean of 34% (P = 0. 001), whereas acetaminophen clearance remained unchanged., Conclusions: These findings indicate that, in cirrhosis, impaired hepatocyte oxygenation contributes to reduced oxidative drug metabolism and that oxidative drug metabolism can be improved by oxygen supplementation.

Background/aims: Capillarization associated with hepatic fibrosis may present a functional barrier to oxygen diffusion into the hepatocyte, and restriction on cellular oxygen supply may represent the rate-limiting constraint on hepatic oxidative drug metabolism. The aim of this study was to test this hypothesis by examining the effect of oxygen supplementation on plasma theophylline clearance in 10 control and 10 cirrhotic rats., Methods: Theophylline (3 mg/kg) was administered intravenously on two separate occasions, 24 hours apart, during which time the rats breathed either room air or oxygen (95%) from 1 hour before dosing until the end of plasma sampling with a randomized order of gas exposure., Results: Theophylline clearance was significantly reduced by a mean of 37% (n = 10; P = 0.003) in cirrhotic rats compared with controls. Oxygen supplementation significantly improved plasma theophylline clearance in cirrhotic rats by a mean of 40% (n = 10; P = 0.007), whereas clearance remained unchanged in healthy rats. Clearance in oxygen-supplemented cirrhotic rats was not significantly different from that in controls (P > 0.05)., Conclusions: These novel findings indicate an important role for hepatic oxygenation in improving drug disposition in cirrhosis, which may have potentially important clinical implications for the management of this disease.