Diagnostic value of diffusion-weighted imaging (DWI) for the assessment of the small bowel in patients with inflammatory bowel disease.

AIM: To evaluate diffusion-weighted imaging (DWI) compared to standard magnetic resonance imaging (sMRI) in the assessment of inflammatory lesions of the small bowel. MATERIALS AND METHODS: Two readers retrospectively analysed MRI images of the small bowel including DWI followed by capsule endoscopy (CE) and ileocolonoscopy (ICS) in 30 consecutive patients with a suspected or established diagnosis of inflammatory bowel disease. Small bowel CE and the combination of CE + ICS were used as the standards of reference. Inflammatory lesions of the small bowel detected at endoscopy were compared with the findings of (1) sMRI alone (MRI without DWI), (2) DWI alone, and (3) sMRI in combination with DWI (sMRI + DWI). The sensitivity, specificity, and accuracy were calculated for all three readouts. The results of the three readouts were compared with each other. RESULTS: Using CE + ICS as the standard of reference, the mean sensitivity and specificity for the detection of inflammatory lesions of the small bowel at sMRI were 55.2% and 99.5%, at DWI 60% and 99%, and at sMRI + DWI 70% and 99%. Interobserver agreement between the two readers was very good (k=0.87-0.95). Two lesions in different patients were only detected at DWI. CONCLUSION: DWI of the small bowel not only allowed for the detection of inflammatory lesions with high accuracy, but also enabled the identification of additional lesions that were not found using sMRI alone.

Hepatic expression of proteasome subunit alpha type-6 is upregulated during viral hepatitis and putatively regulates the expression of ISG15 ubiquitin-like modifier, a proviral host gene in hepatitis C virus infection.

The interferon-stimulated gene 15 (ISG15) plays an important role in the pathogenesis of hepatitis C virus (HCV) infection. ISG15-regulated proteins have previously been identified that putatively affect this proviral interaction. The present observational study aimed to elucidate the relation between ISG15 and these host factors during HCV infection. Transcriptomic and proteomic analyses were performed using liver samples of HCV-infected (n = 54) and uninfected (n = 10) or HBV-infected controls (n = 23). Primary human hepatocytes (PHH) were treated with Toll-like receptor ligands, interferons and kinase inhibitors. Expression of ISG15 and proteasome subunit alpha type-6 (PSMA6) was suppressed in subgenomic HCV replicon cell lines using specific siRNAs. Comparison of hepatic expression patterns revealed significantly increased signals for ISG15, IFIT1, HNRNPK and PSMA6 on the protein level as well as ISG15, IFIT1 and PSMA6 on the mRNA level in HCV-infected patients. In contrast to interferon-stimulated genes, PSMA6 expression occurred independent of HCV load and genotype. In PHH, the expression of ISG15 and PSMA6 was distinctly induced by poly(I:C), depending on IRF3 activation or PI3K/AKT signalling, respectively. Suppression of PSMA6 in HCV replicon cells led to significant induction of ISG15 expression, thus combined knock-down of both genes abrogated the antiviral effect induced by the separate suppression of ISG15. These data indicate that hepatic expression of PSMA6, which is upregulated during viral hepatitis, likely depends on TLR3 activation. PSMA6 affects the expression of immunoregulatory ISG15, a proviral factor in the pathogenesis of HCV infection. Therefore, the proteasome might be involved in the enigmatic interaction between ISG15 and HCV.

Treatment of fulminant acute Hepatitis B with nucles(t)id analogues is safe and does not lead to secondary chronification of Hepatitis B.

Background: Acute hepatitis B virus (HBV) infection is still a major cause of acute liver failure (ALF), necessitating a high rate of emergency liver transplantation (LTx). Acute infection is followed by high viral replication rates leading to hepatocyte death and, ultimately, ALF. The objective of treating HBV-induced ALF thus is to eliminate, or significantly suppress, HBV replication and therefore reduce cell death and support regeneration. Objective: In this retrospective study, we want to evaluate the timing, the safety, and the long-term virological outcome of this approach. Methods/results: In this study, we included 32 patients (16 female and 16 males; median age 39.5 years) with ALF due to hepatitis B, who were transferred to the university hospital Essen, Germany between January 2009 and December 2013. Before treatment, transaminases were highly elevated, bilirubin was increased, and elevated international normalized ratio (INR) revealed impaired liver function. HBV-DNA and HBsAg were positive. All 32 patients received oral antiviral treatment (3 lamivudine, 21 entecavir, and 8 tenofovir) between 1 day and 4 months after diagnosis of acute hepatitis B. One patient died, 2 were transplanted, one died shortly after LTx the other patient survived after LTx. These 3 patients received treatment in a state of advanced liver failure, and 1 patient 4 months after initial diagnosis of hepatitis B. Twenty-nine patients survived without LTx. Five patients were discharged without further follow-up. All 24 remaining patients became HBV-DNA negative in median of 100 days. Twenty-two patients were followed further, and all patients lost their HBsAg in median of 108 days. Sixteen of the 22 patients experienced a seroconversion to anti-HBs in median of 137 days. Four patients who were followed for 1 more year after HBsAg did not develop anti-HBs. None of the patients developed chronic hepatitis B. Conclusion: Immediate treatment of HBV-induced ALF with nucleos(t)id-analogues (NUCs) appears save and prevents LTx and death, and there is no indication for increased chronicity.

Diagnostics and treatment of a severe humoral rejection after liver transplantation: donor-specific antibodies as a still underestimated cause of graft failure.

BACKGROUND: Donor-specific antibodies (DSAs) are increasingly being considered a cause of complications after liver transplant (LT). However, neither monitoring of DSAs nor the appropriate therapeutic procedures for humoral graft damage are yet standardized. Here we report a case of DSA-positive humoral rejection after LT that was successfully treated with plasmapheresis and immunoglobulins. METHODS: Human leukocyte antigen (HLA)-specific DSAs were detected by Luminex bead assay. Patient characteristics, laboratory values, and data about the patient's general condition were documented from April 2013 to June 2015. CASE REPORT: Eighteen months after LT, a 54-year-old man experienced severe hepatopathy with rapidly increasing transaminase activity and total bilirubin levels. Histologic findings were inconclusive, demonstrating chronic cholestasis and minimal positive staining for C4 d. However, an analysis for anti-HLA antibodies detected DSAs against HLA class II molecules with high mean fluorescence intensity. The patient underwent 8 courses of plasmapheresis, resulting in sustained amelioration of his condition and decreases in bilirubin levels and transaminase activity. CONCLUSION: De novo DSAs can be responsible for graft failure after LT. Thus, procedures aimed at detecting DSAs are recommended, and regular monitoring of DSAs after LT is important for individualized risk management. Plasmapheresis is an efficient therapeutic procedure for DSA-associated graft failure.

[Relevance of Ablation Therapies for HCC: "A Real Bridging" for Liver Transplantation?]. / Stellenwert der ablativen Tumortherapie beim HCC: "eine reale Brücke" zur Lebertransplantation?

BACKGROUND: The utilisation of interventional ablation procedures in the context of bridging and downstaging plans for hepatocellular carcinomas before liver transplantation is increasing. The aim of the present study was to summarise current data for the application of bridging and downstaging procedures before liver transplantation. METHODS: The present study is based on an extensive investigation of the literature in PubMed. RESULTS of controlled trials, cohort studies, meta-analyses and reviews were included. RESULTS: Recommendations for the usage of bridging procedures for hepatocellular carcinomas within the Milan criteria and an expected waiting time of more than 6 months until transplantation depend on the size of the lesions and have a low level of evidence. After successful downstaging of hepatocellular carcinomas beyond the Milan criteria into the range of the Milan criteria liver transplantation is recommended with a low level of evidence, as well. CONCLUSION: Randomised controlled trials, clearly proving the success of bridging and downstaging procedures, are not available at the time and are not awaited for ethical reasons. Due to the uncomplicated application and low risk for therapy-associated complications, interventional procedures for bridging and downstaging are accepted and recommended.

[Hepatic steatosis : Differential diagnostics and current aspects]. / Hepatische Steatosen : Differenzialdiagnostik und aktuelle Aspekte.

The frequency of non-alcoholic fatty liver disease (NAFLD) has continously increased over the last few decades in parallel with the increasing prevalence of metabolic syndrome. With the increasing frequency of obesity and type 2 diabetes an increase in non-alcoholic steatohepatitis (NASH) is also to be expected. The NASH-associated liver cirrhosis and primary hepatocellular carcinoma (HCC) are indications for liver transplantation (LTX), which is gaining importance in Germany. In contrast, liver cirrhosis as a result of alcoholic steatohepatitis (ASH) is already the leading cause for LTX in Germany. A significant number of patients with ASH cirrhosis develop HCC. Less common causes of hepatic steatosis are secondary and include chemotherapy-associated steatohepatitis (CASH). In this article the causes, diagnostics and novel therapeutic approaches for the various forms of steatosis are discussed.

Performance characteristics of the VERSANT hepatitis C virus RNA 1.0 (kPCR) assay.

HCV RNA assays are of central importance for virological diagnostics and for clinical planning and monitoring of an antiviral combination treatment of chronic HCV infections. The objective of the pre-market evaluation of the VERSANT HCV RNA 1.0 Assay (kPCR) was to collect analytical performance data for this new method of HCV RNA quantification and to compare them with the high standards that exist in this context. The assay exhibited a specificity of 100%. The mean intra- and inter-assay imprecision was 14.1% and 14.6%, respectively. The detection limit was determined to be 16IU/ml (95% confidence interval: 11.9-30.6IU/ml) and consequently corresponded to the manufacturer's claims (i.e. 15IU/ml). The test exhibited linearity for all HCV genotypes in a broad range from 15 to 10(8)IU HCV RNA/ml. Hence, the kPCR assay in general is well suitable for HCV RNA determinations in clinical practice. However, in a methodological comparison, a considerable under-quantification of the concentrations of HCV genotype 2 and 3 isolates was detected. Provided that the assay's manufacturer will quickly remedy this shortcoming, the VERSANT HCV RNA 1.0 (kPCR) can be called a completely reliable technique for HCV RNA quantification in routine virological diagnostics.

Toll-like receptor-mediated immune responses are attenuated in the presence of high levels of hepatitis B virus surface antigen.

It has been recently shown that Toll-like receptor (TLR) signalling in murine nonparenchymal liver cells (NPCs) is suppressed in the presence of Hepatitis B virus surface antigen (HBsAg). It is not clear, however, whether this is also relevant for the adaptive immune responses and how this effect is mediated. Peripheral blood mononuclear cells (PBMCs) from Hepatitis B virus (HBV) patients and controls were stimulated by TLR ligands in the absence or presence of autologous serum. Interestingly, TLR-mediated cytokine expression (Interleukin-6 and -10) as well as TLR3-induced interferon (IFN) expression in PBMCs of HBV patients was significantly higher than in the healthy volunteers, showing a negative correlation with the levels of HBsAg. In addition, TLR3-mediated IFN-γ production was inhibited in the presence of HBV-containing serum. To mechanistically analyse this observation, murine Kupffer cells (KCs) and sinusoidal endothelial cells (LSECs) were stimulated with TLR3 ligands in the presence or absence of HBsAg. Mixed lymphocyte reactions were performed to study T-cell activation induced by TLR-stimulated NPCs. Gene expression of cytokines and TLR3 was analysed by quantitative rt-PCR, and activation of transcription factors was assessed by Western blot or reporter gene assays. TLR-induced expression of interferon γ, interferon sensitive genes and proinflammatory cytokines in murine KCs and LSECs was efficiently suppressed in the presence of HBsAg, whereas the expression of anti-inflammatory cytokines was enhanced. Activation of NFκB, IRF-3 and MAPKs in these liver cells was potently suppressed by HBsAg. T-cell activation mediated through TLR3-stimulated KCs or LSECs was suppressed by HBsAg which could be reverted by anti-IL-10 antibodies. These findings may, at least in part, explain how HBV evades innate and adaptive immune responses to maintain a persistent infection.

Long-term stimulation of Toll-like receptor 3 in primary human hepatocytes leads to sensitization for antiviral responses induced by poly I:C treatment.

Chronic hepatitis C infection is associated with increased expression of interferon-sensitive genes (ISGs) in the liver, which is, paradoxically, correlated with the nonresponse to interferon (IFN)-based therapies. In the present study PHHs were isolated from HCV-infected or uninfected patients and stimulated with the TLR1-9 ligands for 6-24 h. Expression of cytokines and ISGs was determined by ELISA and qRT-PCR. A comparative analysis was performed for TLR3 signalling, which was also correlated with single nucleotide polymorphisms (SNPs) related to HCV pathogenesis. TLR-activated PHHs produced pro-inflammatory and anti-inflammatory cytokines, whereas IFNs were exclusively induced by TLR3 stimulation. Here, IL-29 and IL-28A were significantly highly expressed than IFN-α and IFN-ß. TLR3-induced IFN response was enhanced in hepatocytes isolated from patients with HCV infection. This hyper-responsiveness could be mimicked in naïve PHHs consistently stimulated with low dose of poly I:C, but not Guardiquimod. The higher responsiveness in PHH isolated from HCV-infected patients could be partially explained by higher frequencies of unfavourable SNP alleles of different SNPs associated with HCV progression and treatment outcome. These data suggest that durable activation of TLR3 but not TLR7, by low doses of viral replicative intermediates, increases the sensitivity to viral invasion. These findings shed new light on the relevance of TLR3 in the pathogenesis of HCV and may provide a possible explanation for the increased ISG expression during chronic HCV infection, the so-called IFN paradox.

MicroRNA-155 controls Toll-like receptor 3- and hepatitis C virus-induced immune responses in the liver.

The hepatitis C virus (HCV) establishes persistent infections despite strong activation of the innate immune system through TLR3 and other sensors. Therefore, we analysed regulatory mechanisms of TLR3-induced immune responses in nonparenchymal liver cells (NPCs). Effects of Interleukin-10 (IL-10), transforming growth factor beta (TGF-ß) and immunoregulatory miR-155 on poly I:C-activated murine (C57BL/6) Kupffer cells (KC) and sinusoidal endothelial cells (LSEC) were assessed in vitro. NPCs were assayed for inflammatory and antiviral cytokines and T-cell (Balb/c)-activating factors. Gene expression of miR-155, IL-10, TGF-ß and interferon sensitive genes (ISGs) in biopsies of patients with HCV was determined by qrt-PCR. TLR3-induced antiviral activity in murine NPCs was potently suppressed by IL-10 and TGF-ß which correlated with decreased TLR3 expression and inhibition of NF-κB and IRF-3 activation. T-cell activation, induced by TLR3-activated NPCs, was also suppressed by IL-10 and TGF-ß, which was associated with a down-regulation of CD80 and CD86. Pretreatment with IL-10 or TGF-ß suppressed TLR3-induced miR-155 expression, which itself positively regulated poly I:C-mediated immune responses, thus counteracting IL-10 or TGF-ß-induced immunosuppression. In addition, hepatic expression of miR-155 was elevated in chronically infected patients with HCV, was associated with an IL-28B SNP (rs12979860) and was inversely correlated with HCV serum load and ISG expression levels. As miR-155 is a key regulator of anti-inflammatory mechanisms that control innate and adaptive hepatic immune responses during HCV infection, miR-155 based therapies may represent a novel mechanism to control HCV in the future.

Addition of diffusion-weighted imaging can improve diagnostic confidence in bowel MRI.

AIM: To evaluate whether the addition of diffusion-weighted imaging (DWI) in bowel abdominal magnetic resonance imaging (MRI) can improve diagnostic confidence. MATERIALS AND METHODS: One hundred and eleven consecutive patients with suspected or known inflammatory bowel disease (n = 59), tumour disease (n = 31), unspecific abdominal pain (n = 16), and suspected graft-versus-host disease (n = 5) underwent bowel MRI using a 1.5 T MRI machine. In addition to T2-weighted (T2W) and contrast-enhanced T1-weighted (CE-T1W) data, axial and coronal DWI sequences were collected (b = 50, 500, 1000). Diagnostic confidence for lesion detection with and without DWI was evaluated using a four-point Likert scale [1 = certainly no lesion(s), 2 = probably no lesion(s), 3 = probably lesion(s), 4 = certainly lesion(s)]. RESULTS: In 11 of 111 patients (10%), the diagnostic confidence was improved by DWI. In seven patients, readers changed their diagnosis from "probable" to "certain presence of lesions". In another four patients, lesions were diagnosed based on DWI, which were not delineated on CE-T1W and T2W imaging. CONCLUSION: DWI of the bowel can provide additional information to the reader and, therefore, improve diagnostic confidence. Hence, additional DWI should be integrated into a standard bowel MRI protocol.

Tacrolimus as a reasonable alternative in a patient with steroid-dependent and thiopurine-refractory autoimmune pancreatitis with IgG4-associated cholangitis.

BACKGROUND: More recently, autoimmune pancreatitis (AIP) in association with IgG4-positive cholangitis (IAC) has been recognised as a new and challenging entity. Currently, initiation of high dose steroids (e.g., prednisolone 0.5 - 1 mg/kg/day) followed by a steroid dose taper in combination with purine antagonists (e.g., azathioprine or 6-mercaptopurine) after resolution has been recommended as standard therapy. CASE REPORT: A 68-year-old male patient was referred to our institution in February 2012 for therapy evaluation of a steroid-dependent course of autoimmune pancreatitis type 1 with IgG4-associated cholangitis. Since the first diagnosis in March 2011, the patient was treated with high-dose steroids with good response. Whenever steroids were tapered down to a daily dose <20 mg, cholestatic liver enzymes increased dramatically despite concurrent immunosuppressive therapy primarily with azathioprine and 6-MP thereafter. Therefore, we restarted steroid therapy (1 mg/kg/day) in combination with tacrolimus achieving a target level of 5 - 7 ng/mL. During the down-tapering phase, follow-up examinations presented a patient in good general condition without jaundice. Moreover, liver and pancreatic enzymes and also immunoglobulins returned to normal values without any evidence of relapse up today (66 weeks). CONCLUSION: In this case, the combination of steroids with tacrolimus seems to be a reasonable alternative in a patient with steroid-dependent and thiopurine-refractory autoimmune pancreatitis with IgG4-associated cholangitis. To date, this is the first description of such a therapeutic approach for this entity.

[Diagnosis of and therapy for hepatocellular carcinoma]. / Diagnostik und Therapie des hepatozellulären Karzinoms.

The interdisciplinary guidelines at the S3 level on the diagnosis of and therapy for hepatocellular carcinoma (HCC) constitute an evidence- and consensus-based instrument that is aimed at improving the diagnosis of and therapy for HCC since these are very challenging tasks. The purpose of the guidelines is to offer the patient (with suspected or confirmed HCC) adequate, scientifically based and up-to-date procedures in diagnosis, therapy and rehabilitation. This holds not only for locally limited or focally advanced disease but also for the existence of recurrences or distant metastases. Besides making a contribution to an appropriate health-care service, the guidelines should also provide the foundation for an individually adapted, high-quality therapy. The explanatory background texts should also enable non-specialist but responsible colleagues to give sound advice to their patients concerning specialist procedures, side effects and results. In the medium and long-term this should reduce the morbidity and mortality of patients with HCC and improve their quality of life.

[Liver parameters in intensive care medicine]. / Leberparameter in der Intensivmedizin.

Elevated liver function tests in ICU-bound patients are associated with a greater risk of mor-tality. Chronic liver diseases as well as acute events and complications of therapy are among the causes. The disorder could further be investigated by assessment of liver cell integrity markers (AST, ALT and GLDH), cholestasis parameters -(bilirubin, GGT, ALP) and liver synthethic function (albumin, coagulation profile). Ultrasound and elastography are cheap and mobile options to evaluate chronic liver disease, cholestasis or perfusion of the liver. The interpretation of the results should include the medical history on the ICU. Liver injury could be due to septic or isch-aemic complications as well as toxic side effects or parenteral nutrition. The main therapeutic option is to identify the cause of the liver dysfuntion and to eliminate it as far as possible.

CCL5 mRNA is a marker for early fibrosis in chronic hepatitis C and is regulated by interferon-α therapy and toll-like receptor 3 signalling.

Mechanisms causing liver fibrosis during chronic hepatitis C virus infection (cHCV) are not sufficiently understood. This study was aimed to identify biomarkers for early fibrosis (EF) and to investigate their potential role in cHCV-related fibrogenesis. To this end, peripheral whole blood (PB) samples from 36 patients with cHCV recruited from two independent cohorts were subjected to microarray analysis 12 h before initiation of peginterferon-alpha (Peg-IFN-α) and ribavirin therapy. Liver biopsies were evaluated using the Batts-Ludwig staging (BL-S) classification system for fibrosis. We showed that gene expression profiles (N = 8) distinguished between EF (BL-S: 0,1) and late fibrosis (LF; BL-S: 2,3,4) with 88.9% accuracy. Fibrosis-related functional annotations for chemokine-'C-C-motif'' ligand 5 (CCL5) provided foundation for focused investigation, and qRT-PCR confirmed that CCL5 mRNA levels (PB) reliably discriminate EF from LF (accuracy: 86.7%). Positive correlations (P < 0.05) with CCL5 mRNA levels and EF discovered gene expression profiles (PB) reflecting stable expression of IFN-α receptor 1, negative regulation of the MyD88-dependent toll-like receptor (TLR) pathway and decreased expression of TLR3 in vivo. Remarkably, Peg-IFN-α suppressed CCL5 mRNA levels (PB) in EF in vivo. These findings along with results from parallel in vitro investigation into the effect of IFN-α or poly I:C (TLR3-agonist) on CCL5 gene expression in hepatic stellate cells (HSC) attest to the multi-site involvement of these pathways in regulating fibrogenesis. In conclusion, we identified novel, reliable biomarkers for EF and exposed functional properties of the molecular network regulating CCL5 biosynthesis in peripheral or hepatic cell types with key roles in cHCV-related liver and/or immune pathogenesis.

Acute management of refractory variceal bleeding in liver cirrhosis by self-expanding metal stents.

BACKGROUND AND AIMS: Current treatment strategies of variceal bleeding (VB) include banding and sclerotherapy. However, up to 10% of bleeding events remain refractory to standard therapy with high mortality. With this study, we aimed to evaluate the implantation of self-expanding metal stents (SEMS) for the management of therapy-refractory variceal bleeding. PATIENTS AND METHODS: Eight cirrhotic patients who presented to our unit with a total of 9 refractory bleeding events were treated by SEMS placement. RESULTS: Stenting resulted in immediate hemostasis in all cases without recurrent bleeding with SEMS in situ. After stabilization, 1 patient was treated by transjugular intrahepatic portosystemic shunt (TIPS) and after the second bleeding episode by TIPS dilation. One patient underwent orthotopic liver transplantation (OLT). The remaining patients were treated with standard drug regimens to reduce portal pressure. The SEMS were removed after a median of 11 days. No acute hemorrhage was noted on stent retrieval. While no early rebleeding occurred in the patients after TIPS implant, TIPS dilation or OLT, 3 out of 5 patients on conservative treatment experienced recurrence of VB within 9 days after SEMS removal. CONCLUSIONS: SEMS placement sufficiently stops hemorrhage in refractory VB. Due to the high rebleeding rate after conservative treatment alone following SEMS removal, this procedure may be utilized as a mere bridging method. Additional interventional and/or surgical methods to effectively reduce portal pressure (i.e. TIPS, OLT) should be considered. Further studies to evaluate the optimum treatment algorithm of refractory esophageal VB are warranted.

Adipokine expression in brown and white adipocytes in response to hypoxia.

BACKGROUND: Adipose tissue has emerged as an important endocrine regulator by secreting hormones referred to as adipokines. Recent studies showed that adipose tissue considerably responds to hypoxia. Although the impact of white adipose tissue on regulative processes is established, the importance of brown adipose tissue in adults has emerged just recently. METHODS: Brown (BA) and white adipocytes (WA) were cultured either in the presence of chemical hypoxia-mimetics or under hypoxic atmosphere of 1% oxygen. Expression of hypoxia-inducible factor 1α (HIF- 1α) was assessed by western blot. The expression levels of several known HIF-1α-regulated proteins [vascular endothelial growth factor (VEGF), leptin, adiponectin, and angiotensinogen (AGT)] were quantified. RESULTS: Both chemical hypoxia-mimetics and physical hypoxia led to increased nuclear HIF-1α expression and to decreased cytoplasmatic adiponectin in both cell types. In contrast, VEGF and AGT expression did not change upon hypoxic stimulation. Leptin was exclusively detectable in WA, while uncoupling-protein 1 (UCP-1) was expressed in BA only. CONCLUSIONS: WA and BA are sensitive to hypoxia, in which HIF-1α expression is induced. Protein expression of adiponectin is hypoxia-dependent, whereas AGT, VEGF, leptin, and UCP-1 expression do not change secondary to hypoxia.

[Role of vitamin K antagonists from a hepatologist's point of view]. / Rolle der Vitamin-K-Antagonisten aus Sicht des Hepatologen.

Vitamin K antagonists are often used as oral anticoagulants for primary and secondary prevention of thromboembolic events. Vitamin K antagonists induce an anticoagulant effect by interfering with the vitamin K metabolism in the liver. Well-known complications are bleeding events and skin necrosis. Recent data indicate increasing numbers of cases with hepatic complications due to vitamin K antagonists ranging from mild hepatopathy to acute liver failure with high mortality. Hepatotoxicity is usually developed after a few months of latency, which is associated with unspecific symptoms, jaundice, elevated transaminase levels as well as cholestatic enzymes. Hepatotoxicity due to vitamin K antagonists is seldom; however, it should be considered in cases of elevated liver enzymes. In this case coumarin therapy should be discontinued. Caution is needed when changing to another coumarin derivative because cross-reactivity has been described.

Hepatocyte apoptotic bodies encasing nonstructural HCV proteins amplify hepatic stellate cell activation: implications for chronic hepatitis C.

Chronic hepatitis C infection leads to increased hepatocyte apoptosis. Because engulfment of apoptotic bodies (ABs) by hepatic stellate cells (HSC) is profibrogenic, we compared the effects of ABs derived from hepatitis C virus (HCV)-negative vs HCV-infected (Con1+) Huh7 hepatoblastoma cells on fibrogenic and activation-related mRNA expression by a human HSC line (LX2). Uptake of Huh7(Con1+) ABs by LX2 cells dose dependently upregulated profibrotic genes (COL1A1, TGFB1; TIMP1; TIMP2). When normalized to the apoptotic cytokeratin-18 M30 neoepitope, HCV(+) ABs exhibited a more pronounced effect than HCV(-) ABs. In contrast, neither noningested ABs nor nucleic acids obtained from Huh7, Huh7(Con1+) or HepG2 cells triggered those AB-dependent effects. Both the engulfment of Huh7(Con1+) ABs and their effects were partially blocked by masking of phosphatidylserine with annexin V and completely inhibited by the class-A scavenger receptor ligand, polyinosinic acid. Our findings demonstrate that AB uptake stimulates HSCs and indicate that HCV infection leads to amplified fibrogenic mRNA expression and enhanced HSC activation.