Juliane Halangk

A degradation-sensitive anionic trypsinogen (PRSS2) variant protects against chronic pancreatitis

Chronic pancreatitis is a common inflammatory disease of the pancreas. Mutations in the genes encoding cationic trypsinogen (PRSS1) and the pancreatic secretory trypsin inhibitor (SPINK1) are associated with chronic pancreatitis. Because increased proteolytic activity owing to mutated PRSS1 enhances the risk for chronic pancreatitis, mutations in the gene encoding anionic trypsinogen (PRSS2) may also predispose to disease. Here we analyzed PRSS2 in individuals with chronic pancreatitis and controls and found, to our surprise, that a variant of codon 191 (G191R) is overrepresented in control subjects: G191R was present in 220/6,459 (3.4%) controls but in only 32/2,466 (1.3%) affected individuals (odds ratio 0.37; P = 1.1 × 10−8). Upon activation by enterokinase or trypsin, purified recombinant G191R protein showed a complete loss of trypsin activity owing to the introduction of a new tryptic cleavage site that renders the enzyme hypersensitive to autocatalytic proteolysis. In conclusion, the G191R variant of PRSS2 mitigates intrapancreatic trypsin activity and thereby protects against chronic pancreatitis.

Hepatitis C treatment in “difficult-to-treat” psychiatric patients with pegylated interferon-alpha and ribavirin: Response and psychiatric side effects†

We investigated and compared the results of treating the chronic hepatitis C (HCV) infection of different groups of psychiatric‐risk patients and controls with pegylated interferon alpha (pegIFN‐α) plus ribavirin. Seventy patients were prospectively screened for psychiatric disorders. Seventeen patients without psychiatric diseases or drug addiction (controls), 22 patients with psychiatric disorders, 18 patients who had received methadone substitution treatment and 13 patients who were former drug users were treated with pegIFN‐α plus ribavirin. Sustained virological response (SVR), adherence, and psychiatric side effects (using the Montgomery‐Asberg Depression Rating Scale and the Brief Psychiatric Rating Scale) in the groups were compared. An SVR was found in 58.6% of all patients: 58.8% of the controls, 50% of psychiatric patients, 72.2% of methadone patients, and 53.8% of former drug users. Methadone‐substituted patients and former drug users had significantly higher dropout rates. Scores for neither depressive nor psychotic symptoms differed significantly between groups during treatment. However, the controls had lower pretreatment scores, followed by a significant higher increase to maximum scores. A stepwise logistic regression model showed that only genotype, not group (control, psychiatric, methadone, or former drug abuse), type of psychiatric diagnosis (affective disorder, personality disorder, or schizophrenic disorder), depression scores before and during treatment, change in depression score, antidepressive treatment, sex, or liver enzymes before treatment, was associated with SVR. Conclusion: In an interdisciplinary treatment setting psychiatric diseases and/or drug addiction did not negatively influence psychiatric tolerability of and antiviral response rate to HCV treatment with pegIFN‐α and ribavirin. (HEPATOLOGY 2007.)

Association of TLR7 single nucleotide polymorphisms with chronic HCV‐infection and response to interferon‐a‐based therapy

Summary.  An efficient immune response against hepatitis C virus (HCV) is necessary to clear infection. As HCV is a single‐stranded RNA virus, a role for TLR7 in the immune response against HCV is possible, and early clinical studies have demonstrated an antiviral effect of TLR7 stimulation. We tested the hypothesis that genetic variations of TLR7 are associated with chronic HCV‐infection and outcome of therapy. The prevalence of three TLR7 variations was analysed in 978 patients with chronic HCV‐infection, 898 patients with chronic liver disease of other aetiologies, and in 203 healthy controls. The prevalence of TLR7 variations was correlated with the response to interferon‐α‐based treatment in 544 patients with chronic HCV‐infection. We analysed TLR7 polymorphisms by melting curve analysis and reconstructed haplotypes. The c.32A>T variation was over‐represented in female patients with chronic HCV‐infection compared to patients with other chronic liver diseases and to healthy controls (P < 0.05). In contrast, c.2403 G>A was less prevalent in male patients with chronic HCV‐infection (P < 0.05). No association was observed for the third variant, c.1‐120T>G. Haplotype analysis confirmed the differential distribution of TLR7 variants between the groups. Within the group of female patients with chronic HCV‐infection, c.32T was predictive of an unfavourable outcome of interferon‐α therapy (P < 0.05). This study reports the association of TLR7 variants with chronic HCV‐infection and with the response to interferon‐α therapy in patients with chronic HCV‐infection. Our results suggest that variations of TLR7 impair the immune response to HCV and imply a gender‐specific effect of this X‐chromosomal variation.

Induction of Interleukin-6 by Hepatitis C Virus Core Protein in Hepatitis C–Associated Mixed Cryoglobulinemia and B-Cell Non–Hodgkin's Lymphoma

Purpose: Chronic hepatitis C carries the risk to develop mixed cryoglobulinemia (MC) and B-cell non–Hodgkins lymphoma (B-NHL), possibly because viral antigens stimulate the hosts inflammatory response via extracellular pattern recognition receptors (PRR). To clarify this issue, we studied whether recognition of hepatitis C virus (HCV) proteins by PRR is involved in the pathogenesis of HCV-associated MC or B-NHL. Experimental Design: Peripheral blood mononuclear cells of patients with HCV-associated B-NHL (n = 12), MC (n = 14), uncomplicated hepatitis C (n = 12), and healthy volunteers (n = 12) were incubated with the recombinant HCV proteins E2, core, and NS3 to study induction of cytokine production, stimulation of B-cell proliferation, and immunoglobulin secretion. In addition, serum levels of interleukin-6 (IL-6) were measured by ELISA. Results: HCV core was the only studied protein, which induced production of IL-6 and IL-8 in CD14+ cells. IL-6 induction was mediated via Toll-like receptor 2 (TLR2) and lead to increased B-cell proliferation in vitro. TLR2 expression on monocytes and IL-6 serum concentrations were increased in all groups of HCV-infected patients compared with healthy controls and were highest in MC (P < 0.05). Conclusions: Increased secretion of IL-6 via stimulation of TLR2 by HCV core protein may play a role in the pathogenesis of hepatitis C–associated MC and B-NHL.

Association of CTLA4 single nucleotide polymorphisms with viral but not autoimmune liver disease.

Background CTLA4 is an inhibitory receptor expressed on a subset of T lymphocytes. Single nucleotide polymorphisms of the CTLA4 gene have been implicated in autoimmune diseases, including autoimmune hepatitis and primary biliary cirrhosis. In reverse form, CTLA4 variations are associated with chronic infections such as chronic hepatitis B. Methods CTLA4 variations −318C>T and +49A>G were analyzed in 2366 patients with chronic liver disease of various etiologies, including 323 patients with chronic hepatitis B virus (HBV) infection, 1181 patients with chronic hepatitis C virus infection, 180 patients with primary biliary cirrhosis, and 127 patients with autoimmune hepatitis, as well as 202 healthy control individuals. Genotyping was performed by melting curve analysis. Results The −318C>T variation was underrepresented in patients with chronic HBV infection compared with healthy controls (14.6 vs. 25.7%, P=0.002) and with patients with chronic liver disease of other origin (14.6 vs. 20.7%, P=0.011). Patients with cryptogenic cirrhosis also showed a lower frequency of the −318T allele than healthy controls (12.0 vs. 25.7%, P=0.014). No association of the +49G>A variation was found with any diagnosis, including autoimmune hepatitis and primary biliary cirrhosis. Conclusion We describe the association of the CTLA4 −318C>T variation with chronic HBV infection and cryptogenic cirrhosis but find no association of the +49G>A variation with autoimmune liver disease.

Keratin 8 sequence variants in patients with pancreatitis and pancreatic cancer.

Keratin 8 (KRT8) is one of the major intermediate filament proteins expressed in single-layered epithelia of the gastrointestinal tract. Transgenic mice over-expressing human KRT8 display pancreatic mononuclear infiltration, interstitial fibrosis and dysplasia of acinar cells resulting in exocrine pancreatic insufficiency. These experimental data are in accordance with a recent report describing an association between KRT8 variations and chronic pancreatitis. This prompted us to investigate KRT8 polymorphisms in patients with pancreatic disorders. The KRT8 Y54H and G62C polymorphisms were assessed in a cohort of patients with acute and chronic pancreatitis of various aetiologies or pancreatic cancer originating from Austria (n=16), the Czech Republic (n=90), Germany (n=1698), Great Britain (n=36), India (n=60), Italy (n=143), the Netherlands (n=128), Romania (n=3), Spain (n=133), and Switzerland (n=129). We also studied 4,234 control subjects from these countries and 1,492 control subjects originating from Benin, Cameroon, Ethiopia, Ecuador, and Turkey. Polymorphisms were analysed by melting curve analysis with fluorescence resonance energy transfer probes. The frequency of G62C did not differ between patients with acute or chronic pancreatitis, pancreatic adenocarcinoma and control individuals. The frequency of G62C varied in European populations from 0.4 to 3.8%, showing a northwest to southeast decline. The Y54H alteration was not detected in any of the 2,436 patients. Only 3/4,580 (0.07%) European, Turkish and Indian control subjects were heterozygous for Y54H in contrast to 34/951 (3.6%) control subjects of African descent. Our data suggest that the KRT8 alterations, Y54H and G62C, do not predispose patients to the development of pancreatitis or pancreatic cancer.

Evaluation of complement factor 5 variants as genetic risk factors for the development of advanced fibrosis in chronic hepatitis C infection

BACKGROUND/AIMS Intercross studies in inbred mice susceptible or resistant to liver fibrosis revealed complement factor 5 as a quantitative trait gene associated with the development of fibrosis. In 277 patients with hepatitis C, two C5 SNPs, rs17611 and rs2300929, have been associated with advanced fibrosis. METHODS We investigated the association of these C5 SNPs with advanced fibrosis in 1435 HCV infected patients and in 1003 patients with other liver diseases. We performed genotyping with melting curve analysis using fluorescence resonance energy transfer probes in the LightCycler. RESULTS The defined high-risk genotypes (AA and TT) and alleles (A and T) were not associated with advanced fibrosis in HCV patients when Chi square testing and logistic regression analysis were applied (rs17611A 0.45 in F0-1 vs. 0.43 in F2-4, P=0.31; rs2300929T 0.91 F0-1 and 0.91 in F2-4, P=0.82). In the group of patients with liver diseases other than HCV we neither found an association of the C5 SNPs with advanced fibrosis nor an overrepresentation of the SNPs in patients with cirrhosis. CONCLUSIONS We found no evidence that these C5 SNPs are genetic risk factors for the development of advanced fibrosis in chronic HCV infection or other chronic liver diseases.

No Role of Matrixmetalloproteinase‐3 Genetic Promoter Polymorphism 1171 as a Risk Factor for Cirrhosis in Alcoholic Liver Disease

BACKGROUND As only a minority of alcoholics develop cirrhosis, polymorphic genes, whose products are involved in fibrosis development were suggested to confer individual susceptibility. We tested whether a functional promoter polymorphism in the gene encoding matrix metalloproteinase-3 (MMP-3; 1171 5A/6A) was associated liver cirrhosis in alcoholics. METHODS Independent cohorts from the UK and Germany were studied. (i) UK cohort: 320 alcoholic cirrhotics and 183 heavy drinkers without liver damage and (ii) German cohort: 149 alcoholic cirrhotics, 220 alcoholic cirrhotics who underwent liver transplantation and 151 alcoholics without liver disease. Patients were genotyped for MMP-3 variants by restriction fragment length polymorphism, single strand confirmation polymorphism, and direct sequencing. In addition, MMP-3 transcript levels were correlated with MMP-3 genotype in normal liver tissues. RESULTS Matrix metalloproteinase-3 genotype and allele distribution in all 1023 alcoholic patients were in Hardy-Weinberg equilibrium. No significant differences in MMP-3 genotype and allele frequencies were observed either between alcoholics with or without cirrhosis. There were no differences in hepatic mRNA transcription levels according to MMP-3 genotype. CONCLUSIONS Matrix metalloproteinase-3 1171 promoter polymorphism plays no role in the genetic predisposition for liver cirrhosis in alcoholics. Stringently designed candidate gene association studies are required to exclude chance observations.

Relevance of endotoxin receptor CD14 and TLR4 gene variants in chronic liver disease

Objective. The lipopolysaccharide (LPS)-triggered release of inflammatory cytokines from Kupffer cells is mediated via the CD14/TLR4 receptor complex. This inflammatory pathway can be influenced by alterations in genes encoding for LPS receptor components. Thus, a -260 C>T transition in the CD14 promoter is thought to result in enhanced CD14 expression thereby increasing the LPS responsiveness in chronic liver diseases, whereas a D299G exchange in the TLR4 gene has the opposite effect. Our objective was to analyze these two variations. Material and methods. The study comprised 1712 patients with chronic liver diseases of different etiologies and 385 healthy controls. Genotyping was carried out by melting curve analysis with fluorescence resonance energy transfer (FRET) probes in the LightCycler. Results. Genotype frequencies of CD14 -260C>T and TLR4 D299G did not significantly differ between patients and controls (CD14 TT 21.6% versus 21.8%; TLR4 DG or GG 9.7% versus 10.4%). We found no significant correlation of these alterations with disease course either in the groups of patients with alcoholic liver disease or hepatitis C virus (HCV) infection or among patients requiring liver transplantation. A significantly higher frequency of the CD14 -260TT genotype was observed (36.6% versus 21.8% in healthy controls, p=0.036) only in a small subgroup of patients (n=41) with mild cryptogenic chronic liver disease. Conclusions. Variants within these LPS receptor genes were equally distributed among patients with chronic liver diseases of different etiologies and obviously do not confer an increased risk for the severity of these chronic liver processes.

The role of epoxide hydrolase Y113H gene variant in pancreatic diseases.

Objectives: Chronic pancreatitis (CP) and pancreatic adenocarcinoma (pCA) are associated with risk factors such as alcohol intake and tobacco smoking. Microsomal epoxide hydrolase (EPHX1) is a phase II detoxifying enzyme capable of tobacco-borne toxicant inactivation. We studied the role of the EPHX1 c.337T>C (p.Y113H) variant, whichleads to altered enzyme activity, in pancreatic diseases. Methods: We genotyped 2391 patients by melting curve analysis. Weenrolled 367 patients with pCA, 341 patients with alcoholic CP (aCP), 431 patients with idiopathic CP or hereditary pancreatitis, 192 patients with acute pancreatitis, and 679 controls of German descent. We replicated data in 77 patients with aCP and 304 controls from The Netherlands. Results: In German patients with aCP, Y113 was more common than in controls (allele frequencies, 0.73 vs 0.68; risk ratio, 1.21 [95% confidence interval, 1.05-1.39]). However, we could not confirm this association in the Dutch population (allele frequencies, 0.62 vs 0.68, P=not significant). In total, Y113 frequency was 0.71 in aCP and 0.68 in controls (P = not significant). Allele frequencies did not differ in the other disease groups (acute pancreatitis, 0.69; idiopathic CP or hereditary pancreatitis, 0.68; pCA, 0.68; and control, 0.68). Conclusions: The EPHX1 Y113H variant is not associated with pancreatic diseases indicating that EPHX1 does not play a significant role in the initiation of pancreatic inflammation or cancer.