Kh Weiss

In vivo RNAi screening identifies a mechanism of sorafenib resistance in liver cancer

In solid tumors, resistance to therapy inevitably develops upon treatment with cytotoxic drugs or molecularly targeted therapies. Here, we describe a system that enables pooled shRNA screening directly in mouse hepatocellular carcinomas (HCC) in vivo to identify genes likely to be involved in therapy resistance. Using a focused shRNA library targeting genes located within focal genomic amplifications of human HCC, we screened for genes whose inhibition increased the therapeutic efficacy of the multikinase inhibitor sorafenib. Both shRNA-mediated and pharmacological silencing of Mapk14 (p38α) were found to sensitize mouse HCC to sorafenib therapy and prolong survival by abrogating Mapk14-dependent activation of Mek-Erk and Atf2 signaling. Elevated Mapk14-Atf2 signaling predicted poor response to sorafenib therapy in human HCC, and sorafenib resistance of p-Mapk14-expressing HCC cells could be reverted by silencing Mapk14. Our results suggest that a combination of sorafenib and Mapk14 blockade is a promising approach to overcoming therapy resistance of human HCC.

Reduction in alkaline phosphatase is associated with longer survival in primary sclerosing cholangitis, independent of dominant stenosis

Alkaline phosphatase (ALP) is an important serum marker in primary sclerosing cholangitis (PSC). Patients with obstruction of the large bile ducts due to dominant strictures (DS) are a special, clinically important phenotype.

A Frequent PNPLA3 Variant Is a Sex Specific Disease Modifier in PSC Patients with Bile Duct Stenosis

Background & Aims Primary sclerosing cholangitis predominantly affects males and is an important indication for liver transplantation. The rs738409 variant (I148M) of the PNPLA3 gene is associated with alcoholic and non-alcoholic liver disease and we evaluated its impact on the disease course of PSC. Methods The I148M polymorphism was genotyped in 121 German PSC patients of a long-term prospective cohort and 347 Norwegian PSC patients. Results In the prospective German cohort, actuarial survival free of liver transplantation was significantly reduced for I148M carriers (p = 0.011) compared to wildtype patients. This effect was restricted to patients with severe disease, as defined by development of dominant stenosis (DS) requiring endoscopic intervention. DS patients showed markedly decreased survival (p = 0.004) when carrying the I148M variant (I148M: mean 13.8 years; 95% confidence interval: 11.6–16.0 vs. wildtype: mean 18.6 years; 95% confidence interval: 16.3–20.9) while there was no impact on survival in patients without a DS (p = 0.87). In line with previous observations of sex specific effects of the I148M polymorphism, the effect on survival was further restricted to male patients (mean survival 11.9 years; 95% confidence interval: 10.0–14.0 in I148M carriers vs. 18.8 years; 95% confidence interval: 16.2–21.5 in wildtype; p<0.001) while female patients were unaffected by the polymorphism (p = 0.65). These sex specific findings were validated in the Norwegian cohort (p = 0.013). Conclusions In male PSC patients with severe disease with bile duct stenosis requiring intervention, the common I148M variant of the PNPLA3 gene is a risk factor for reduced survival.

Fut2 genotype is a risk factor for dominant stenosis and biliary candida infections in primary sclerosing cholangitis

A recent genome‐wide association study identified the FUT2 secretor status and genotype defined by the single‐nucleotide polymorphism rs601338 as potential genetic risk factor in primary sclerosing cholangitis (PSC), which significantly influences biliary bacterial composition.

Risk factors and outcome in patients with primary sclerosing cholangitis with persistent biliary candidiasis

BackgroundCandidiasis is commonly observed in patients with primary sclerosing cholangitis (PSC), but the clinical risk factors associated with its presence have not been fully investigated. In this study, we aimed to analyse the incidence, risk factors, and transplantation-free survival in primary sclerosing cholangitis (PSC) patients with persistent biliary candidiasis.MethodsWe retrospectively analysed patients diagnosed with PSC who were admitted to our department during 2002 to 2012. One-hundred fifty patients whose bile cultures were tested for fungal species were selected, and their clinical and laboratory parameters were investigated. The results of endoscopic retrograde cholangiography (ERC) and bile cultures were analysed using chart reviews. The cases of biliary candidiasis were sub-classified as transient or persistent.ResultsThirty out of 150 (20.0%) patients had biliary candidiasis. Although all patients demonstrated comparable baseline characteristics, those with biliary candidiasis showed significantly reduced transplantation-free survival (p < 0.0001) along with a markedly elevated frequency of cholangiocarcinoma (CCA) (p = 0.04). The patients were further sub-classified according to the transient (15/30) or persistent (15/30) nature of their biliary candidiasis. A subgroup analysis showed reduced survival with a greater necessity for orthotopic liver transplantation (OLT) only in patients with persistence of Candida (p = 0.007). The survival in the patients with transient biliary candidiasis was comparable to that in candidiasis-free patients. In a multivariate regression analysis that included Mayo risk score (MRS), sex, age, dominant stenosis, inflammatory bowel disease, autoimmune hepatitis overlap syndrome, and number of times ERC was performed, biliary candidiasis was an independent risk factor for reduced survival (p = 0.008). Risk factors associated with acquisition of biliary candidiasis were age at PSC diagnosis and number of ERCs.ConclusionsThe persistence of biliary candidiasis is associated with markedly reduced transplantation-free survival in PSC patients. By contrast, actuarial survival in patients with transient biliary candidiasis approaches that for patients without any evidence of biliary candidiasis. Further studies on the treatment of persistent biliary candidiasis in patients with PSC are warranted.

Cardiac volume overload and pulmonary hypertension in long‐term follow‐up of patients with a transjugular intrahepatic portosystemic shunt

Transjugular intrahepatic portosystemic shunt (TIPSS) cause haemodynamic changes in patients with cirrhosis, yet little is known about long‐term cardiopulmonary outcomes.

Biliary phosphatidylcholine and lysophosphatidylcholine profiles in sclerosing cholangitis

AIM To analyze phospholipid profiles in intrahepatic bile from patients with primary sclerosing cholangitis (PSC) and secondary sclerosing cholangitis (SSC). METHODS Intrahepatic bile specimens collected via endoscopic retrograde cholangiography from 41 patients were analyzed. Fourteen of these patients were diagnosed with PSC, 10 with SSC, 11 with choledocholithiasis or no identifiable biliary disease, and 6 with cholangiocellular carcinoma (CCC). Bile acid, cholesterol, protein, and bilirubin contents as well as pancreas lipase activity in bile were determined by biochemical methods. Phosphatidylcholine (PC) and lysophosphatidylcholine (LPC) species were quantified using nano-electrospray ionization tandem mass spectrometry. RESULTS Bile from all the examined patient groups showed a remarkably similar PC and LPC species composition, with only minor statistical differences. Total biliary PC concentrations were highest in controls (8030 ± 1843 μmol/L) and lowest in patients with CCC (1969 ± 981 μmol/L) (P = 0.005, controls vs SSC and CCC, respectively, P < 0.05). LPC contents in bile were overall low (4.2% ± 1.8%). Biliary LPC/PC ratios and ratios of biliary PC to bilirubin, PC to cholesterol, PC to protein, and PC to bile acids showed no intergroup differences. CONCLUSION PC and LPC profiles being similar in patients with or without sclerosing cholangitis, these phospholipids are likely not of major pathogenetic importance in this disease group.

Effects of Increased Von Willebrand Factor Levels on Primary Hemostasis in Thrombocytopenic Patients with Liver Cirrhosis

In patients with liver cirrhosis procoagulant and anticoagulant changes occur simultaneously. During primary hemostasis, platelets adhere to subendothelial structures, via von Willebrand factor (vWF). We aimed to investigate the influence of vWF on primary hemostasis in patients with liver cirrhosis. Therefore we assessed in-vitro bleeding time as marker of primary hemostasis in cirrhotic patients, measuring the Platelet Function Analyzer (PFA-100) closure times with collagen and epinephrine (Col-Epi, upper limit of normal ≤165 s) or collagen and ADP (Col-ADP, upper limit of normal ≤118 s). If Col-Epi and Col-ADP were prolonged, the PFA-100 was considered to be pathological. Effects of vWF on primary hemostasis in thrombocytopenic patients were analyzed and plasma vWF levels were modified by adding recombinant vWF or anti-vWF antibody. Of the 72 included cirrhotic patients, 32 (44.4%) showed a pathological result for the PFA-100. They had mean closure times (± SD) of 180±62 s with Col-Epi and 160±70 s with Col-ADP. Multivariate analysis revealed that hematocrit (P = 0.027) and vWF-antigen levels (P = 0.010) are the predictors of a pathological PFA-100 test in cirrhotic patients. In 21.4% of cirrhotic patients with platelet count ≥150/nL and hematocrit ≥27.0%, pathological PFA-100 results were found. In thrombocytopenic (<150/nL) patients with cirrhosis, normal PFA-100 results were associated with higher vWF-antigen levels (462.3±235.9% vs. 338.7±151.6%, P = 0.021). These results were confirmed by multivariate analysis in these patients as well as by adding recombinant vWF or polyclonal anti-vWF antibody that significantly shortened or prolonged closure times, respectively. In conclusion, primary hemostasis is impaired in cirrhotic patients. The effect of reduced platelet count in cirrhotic patients can at least be partly compensated by increased vWF levels. Recombinant vWF could be an alternative to platelet transfusions in the future.

Chapter 19 – Novel perspectives on Wilson disease treatment

Wilson disease is an autosomal-recessive copper overload disorder causing hepatic and neurologic symptoms. Commonly used medical therapy shows satisfactory results with regard to hepatic disease but only limited effects in neurologically affected patients. In recent years several new therapy options have been developed, showing promising results that might improve the management of Wilson disease in the near future. Optimization of treatment regimens depending on biochemical response pattern seems worthwhile, especially in the decoppering phase of therapy. The chelator tetrathiomolybdate (TTM) is a promising therapy option, currently under clinical investigation. TTM is a fast-acting and very potent chelator and appears to be associated with early neurologic deterioration after initiation of therapy to a lower extent than the drugs currently used. Treatment with nonchelating drugs characterized by alternative modes of action is under investigation, but restricted to animal or in vitro studies to date. This includes basic research studies demonstrating proof of principle for successful cell or gene therapy in Wilson disease in order to restore sufficient biliary copper excretion, even before the onset of disease.

Impact of age at diagnosis on disease progression in patients with primary sclerosing cholangitis

Background The median age of diagnosis of primary sclerosing cholangitis (PSC) is ∼30–40 years. Objective We aimed to analyse disease progression and liver-dependent survival in patients diagnosed with PSC after 50 years of age. Methods Patients with PSC were analysed with regard to their age at diagnosis. Patients with a first diagnosis of PSC after the age of 50 years were considered as the late-onset group. Results A total of 32/215 (14.9%) patients were diagnosed with PSC after 50 years of age. The proportion of females was significantly higher among patients with late-onset PSC (48.4 vs. 27.3%; p = 0.02). Patients with later diagnosis required dilatation therapy more often due to dominant stenosis (84.2 vs. 53.1%; p = 0.01) and suffered from recurrent cholangitis more often (48.3 vs. 21.0%; p = 0.003). Patients with late-onset PSC had reduced transplantation-free survival (10.5 ± 0.6 years vs. 20.8 ± 1.7 years, p < 0.0001), with progredient liver failure and cholangiocarcinoma as the leading causes of death. Conclusions Patients with later age at diagnosis of PSC displayed a different clinical phenotype with a different sex ratio, immune status and an increased risk for progressive liver failure and biliary malignancies.