No abstract

Impaired activity of natural killer cells has been proposed as a mechanism contributing to viral persistence in hepatitis C virus (HCV) infection. Natural cytotoxicity is regulated by interactions of HLA-E with inhibitory CD94/NKG2A receptors on natural killer (NK) cells. Here, we studied whether HCV core encodes peptides that bind to HLA-E and inhibit natural cytotoxicity. We analyzed 30 HCV core-derived peptides. Peptide-induced stabilization of HLA-E expression was measured flow cytometrically after incubating HLA-E-transfected cells with peptides. NK cell function was studied with a (51)chromium-release-assay. Intrahepatic HLA-E expression was analyzed by an indirect immunoperoxidase technique and flow cytometry of isolated cells using a HLA-E-specific antibody. We identified peptide aa35-44, a well-characterized HLA-A2 restricted T cell epitope, as a peptide stabilizing HLA-E expression and thereby inhibiting NK cell-mediated lysis. Blocking experiments confirmed that this inhibitory effect of peptide aa35-44 on natural cytotoxicity was mediated via interactions between CD94/NKG2A receptors and enhanced HLA-E expression. In line with these in vitro data we found enhanced intrahepatic HLA-E expression on antigen-presenting cells in HCV-infected patients. Our data indicate the existence of T cell epitopes that can be recognized by HLA-A2 and HLA-E. This dual recognition may contribute to viral persistence in hepatitis C.

Acute hepatitis B progresses to liver failure with the need of liver transplantation in about 1% of cases. We treated patients with severe acute or fulminant hepatitis B with lamivudine in an attempt to prevent hepatitis B virus (HBV) reinfection after potential liver transplantation. Since September 2000, 17 patients with severe acute or fulminant HBV infection were treated with 100 or 150 mg lamivudine daily once we had evidence for a severe course as indicated by an INR >2.0. These were compared to a historic control from our unit and to external patients. Fourteen of the 17 patients (82.4%) survived with full recovery without liver transplantation. All these 14 individuals cleared HBsAg on lamivudine within less than 6 months. Twelve patients recovered quickly as indicated by a normalized prothrombin time within 1 week while two patients had a more prolonged course. None of the patients showed an adverse event. Three patients requiring transplantation despite lamivudine therapy had more advanced disease on admission, of whom one had additionally ingested paracetamol (acetaminophen) while the second was already HBV-DNA negative by polymerase chain reaction on admission. The lamivudine treated patients had significant higher frequency of survival without liver transplantation 82.4 vs 20% (4/20) in the historic control (P < 0.001). Similar data were derived from external centres using lamivudine (15/20, 75%). Lamivudine is safe in patients with severe acute or fulminant hepatitis B, leading to fast recovery with the potential to prevent liver failure and liver transplantation when administered early enough.

The contribution of the acute phase inducer interleukin 6 (IL-6) in the pathogenesis of liver diseases is yet unclear. Our analysis showed enhanced expression of IL-6 in livers derived from patients with acute and chronic liver diseases. Additionally, IL-6 plasma levels were significantly increased in patients with chronic liver diseases and showed an inverse correlation with biochemical markers of liver function and a positive correlation with inflammatory markers, signs of portal hypertension, and the degree of liver fibrosis. To prove the relevance of these clinical findings, we applied the tetrachlorcarbonide (CCl 4 ) model to conditional knockout animals (Cre/loxP system) for gp130, the common signal transducer of IL-6 family cytokines. Cre recombinases were expressed through a hepatocyte (AlfpCre) and a ubiquitous (MxCre) control element. Gp130 deleted mice had a totally abolished STAT3 activation and acute phase response induction, but gp130 deletion had no effect on the degree of acute liver injury and subsequent hepatocyte proliferation. In contrast, during chronic liver injury induced by biweekly application of CCl 4 , deletion of the gp130 receptor in nonparenchymal liver cells and not hepatocytes resulted in fibrosis progression. In conclusion, our experiments indicate an involvement of IL-6 in the pathogenesis of liver diseases and suggest a protective role of IL-6/gp130-dependent pathways in nonparenchymal liver cells during fibrosis progression in chronic liver diseases. (HEPATOLOGY 2003;38:218-229.)

Background: Diverticular disease is one of the most common disorders of the gastrointestinal tract. 28-45% of the population develop colonic diverticula, while about 25% suffer symptoms and about 5% complications. Aim: To create formal guidelines for diagnosis and management. Methods: Six working groups with 44 participants analyzed key questions in subject areas assigned to them. Following a systematic literature search, 451 publications were included. Consensus was obtained by agreement within the working groups, two Delphi processes and a guideline conference. Results: Targeted management of diverticular disease requires a classificatory diagnosis. A new classification was created. In addition to the clinical examination, intestinal ultrasound or computed tomography is the determining factor. Interval colonoscopy is recommended to exclude comorbidities. A low-fiber diet, obesity, lack of exercise, smoking and immunosuppression have an adverse impact on diverticulosis. This can lead to diverticulitis. Antibiotics are no longer recommended in uncomplicated diverticulitis if no risk factors such as immunosuppression are present. If close monitoring is ensured, uncomplicated diverticulitis can be treated on an outpatient basis. Complicated diverticulitis should be treated in hospital, involving broad-spectrum antibiotic therapy, where necessary abscess drainage, and surgery, if possible laparoscopically. In the case of chronic relapsing diverticulitis, the risk of perforation decreases with each episode, so that surgery is no longer recommended after the second episode but only following individual assessment. Conclusions: New findings on diverticular disease call into question the overuse of antibiotics and excessive indications for surgery. Targeted treatment requires a precise diagnosis and intensive interdisciplinary cooperation. i 2014 S. Karger AG, Basel

Upregulation of RhoA and Rho-kinase contributes to increased intrahepatic resistance in cirrhotic rats and to an increased sensitivity of cirrhotic livers to vasoconstrictors.

CC-chemokines recruit and activate macrophages and T lymphocytes, the major components of inflammatory infiltrates in fulminant hepatic failure (FHF). To analyse the role of CC-chemokines in the pathogenesis of FHF, this study examined serum levels and intrahepatic expression of MCP-1, MIP-1alpha, MIP-1beta, and RANTES in the livers and sera of patients with FHF and controls by ELISA, immunohistochemistry, and competitive RT-PCR. Serum levels and intrahepatic expression of all chemokines studied in FHF exceeded the levels in chronic liver diseases and normal controls. Distinct patterns of expression of each chemokine were noted on Kupffer cells, sinusoidal endothelial cells, hepatocytes, lymphocytes, and bile ducts. Intrahepatic chemokine expression correlated closely with the extent of infiltration by macrophages and T lymphocytes (r = 0.65-0.95, p < 0.001). The functional relationship between intrahepatic chemokine release and infiltration was confirmed in chemotaxis assays by inhibiting chemotaxis induced by homogenates of liver tissue obtained from FHF patients with neutralizing MCP-1, MIP-1alpha, MIP-1beta, and RANTES antibodies. The time course of CC-chemokine release was studied in the concanavalin A and the galactosamine/LPS mouse models of FHF. In both models, intrahepatic chemokine up-regulation occurred as an early event prior to hepatic infiltration and liver damage. The data indicate that an abundant intrahepatic release of CC-chemokines is an early and pivotal step in the pathogenesis of FHF.

In cirrhosis, splanchnic vasodilation contributes to portal hypertension, subsequent renal sodium retention, and formation of ascites. Urotensin II(U-II) is a constrictor of large conductive vessels. Conversely, it relaxes mesenteric vessels, decreases glomerular filtration, and increases renal sodium retention. In patients with cirrhosis, U-II plasma levels are increased. Thus, we investigated hemodynamic and renal effects of U-II and its receptor antagonist, palosuran, in cirrhotic bile duct-ligated rats (BDL). In BDL and sham-operated rats, we studied acute effects of U-II (3 nmol/kg; intravenously) and palosuran (10 mg/kg; intravenously) and effects of oral administration of palosuran (30 mg/kg/day; 3 days) on hemodynamics and renal function. We localized U-II and U-IIreceptor (UTR) in livers and portal veins by immunostaining. We determined U-II-plasma levels by enzyme-linked immunosorbent assay (ELISA), and mesenteric nitrite/nitrate-levels by Griessreaction. RhoA/Rho-kinase and endothelial nitric oxide synthase ( P ortal hypertension in liver cirrhosis is mediated by an increased portal tributary blood flow 1 and an increase in intrahepatic resistance to portal flow. 2 The increased portal tributary blood flow is attributable to decreased splanchnic vascular resistance and consecutive splanchnic vasodilation. Consequences of this vasodilation are activation of the renin angiotensin aldosterone system, renal sodium retention, and formation of ascites. 3 This splanchnic vasodilation is mediated by an overproduction of the vasodilator nitric oxide (NO) 4,5 and by concomitant defects in contractile signaling. Thus, we have recently shown that a decrease in RhoA/Rho-kinase signaling contributes to vasodilation in cirrhosis. 6,7 Urotensin II (U-II) is a cyclic oligopeptide with vasoactive potential. [8][9][10][11] By activation of the urotensin II receptor (UTR), U-II might influence different pathways, depending on the cells and vascular compartment where Abbreviations: ⌬C T , the difference in the number of PCR