"Die Rolle antimikrobieller Peptide im weiblichen Genitaltrakt unter besonderer Berücksichtigung HPV-assoziierter Läsionen"

Genitale Infektionen mit humanen Papillomaviren (HPV) gehören weltweit zu den häufigsten sexuell übertragbaren Krankheiten. Infektionen mit einem Low-Risk-HPV-Typ führen im Genitalbereich zur Ausprägung von Condylomata acuminata (Feigwarzen), High-Risk-HPV-Typen sind für die Entstehung des Zervixkarzinoms ursächlich. Das Virus infiziert die Basalschicht des Plattenepithels, welches die erste Schutzbarriere gegen pathogene Mikroorganismen darstellt. Eine Abwehrfunktion von Epithelien ist die Produktion antimikrobieller Peptide (AMP). Wichtige Gruppen dieser „körpereigenen Antibiotika“ sind die Defensine, die sich weiter in α- und β-Defensine unterteilen lassen, und die Cathelicidine, von denen im Menschen nur ein Genprodukt, das LL-37, hergestellt wird. Weitere Vertreter sind die RNase7 und das Psoriasin. AMP haben die Fähigkeit mit der Membran von Mikroorganismen zu interagieren und können so Gram-positive und Gram-negative Bakterien, Pilze und einige behüllte Viren abtöten. Einige der Peptide sind durch bakterielle Bestandteile oder inflammatorische Zytokine induzierbar, andere werden auf einem konstanten Niveau gebildet. Über das Verhalten der AMP bei viralen Infektionen ist bisher wenig bekannt. Ihre Regulation bei Infektionen mit unbehüllten Viren wurde in dieser Arbeit am Beispiel von genitalen HPV-Infektionen mit Ausprägung von Condylomata acuminata untersucht. Zu diesem Zweck wurden Gewebeproben von HPV-infizierter Schleimhaut aus Arealen ohne klinische Veränderungen und aus Arealen mit Condylomata acuminata entnommen. Zum Vergleich wurde auch gesunde Vaginalschleimhaut untersucht. Das Verhalten der antimikrobiellen Peptide wurde sowohl auf mRNA-Ebene mittels quantitativer real-time PCR als auch auf Proteinebene mittels immunhistochemischen Färbungen analysiert. Die untersuchten β-Defensine, hBD-1, -2 und -3, waren sowohl im gesunden als auch im HPV-infizierten Gewebe in deutlicher Konzentration nachweisbar und zeigten im HPV-infizierten Gewebe mit Condylomata acuminata einen signifikante Steigerung der Expression. Dieser Anstieg war für hBD-2 auch auf Proteinebene mittels Immunhistochemie nachweisbar. RNase7 und Psoriasin wurden im gesunden und HPV-infizierten Gewebe ebenfalls in deutlichen Konzentrationen exprimiert. Sowohl die Genexpression als auch die Proteinexpression des Psoriasin steigerten sich bei Vorliegen einer HPV-Infektion. Das Vorkommen von RNase7 unterlag hingegen weder auf mRNA- noch auf Proteinebene starken Schwankungen. Sämtliche α-Defensine konnten weder im gesunden noch im HPV-infizierten Gewebe in nennenswerten Konzentrationen nachgewiesen werden. Auch für LL-37 gelang der Nachweis auf mRNA-Ebene nicht. Das LL-37-Protein konnte hingegen durch die immunhistochemischen Färbungen detektiert werden und zeigte eine gesteigerte Bildung im HPV-infizierten Epithel. Die hohe mRNA-Expression der untersuchten AMP und der signifikante Anstieg dieser bei vorliegender HPV-Infektion belegen, dass sie an der lokalen Immunantwort des Scheidenepithels gegen pathogene Mikroorganismen beteiligt sind. Die größte Bedeutung kommt dabei den β-Defensinen und dem Psoriasin zu, die des Weiteren eine deutliche Induktion durch HPV zeigten. Auch das als nicht induzierbar geltende hBD-1 wies eine signifikante Steigerung der Genexpression auf. Für das durch bakterielle Bestandteile induzierbare antimikrobielle Peptid RNase7 konnte hingegen keine signifikant erhöhte Bildung bei Kontakt mit dem Virus im Vergleich zum gesunden Gewebe nachgewiesen werden, das Peptid war jedoch in allen untersuchten Arealen in deutlichen Konzentrationen nachweisbar. Dieses bestätigt, dass die Regulation der untersuchten antimikrobiellen Peptide unterschiedlich zu sein scheint, je nachdem, ob eine virale oder bakterielle Infektion vorliegt

Evaluation of genome-wide loci of iron metabolism in hereditary hemochromatosis identifies PCSK7 as a host risk factor of liver cirrhosis

Genome-wide association studies (GWAS) have revealed genetic determinants of iron metabolism, but correlation of these with clinical phenotypes is pending. Homozygosity for HFE C282Y is the predominant genetic risk factor for hereditary hemochromatosis (HH) and may cause liver cirrhosis. However, this genotype has a low penetrance. Thus, detection of yet unknown genetic markers that identify patients at risk of developing severe liver disease is necessary for better prevention. Genetic loci associated with iron metabolism (TF, TMPRSS6, PCSK7, TFR2 and Chr2p14) in recent GWAS and liver fibrosis (PNPLA3) in recent meta-analysis were analyzed for association with either liver cirrhosis or advanced fibrosis in 148 German HFE C282Y homozygotes. Replication of associations was sought in additional 499 Austrian/Swiss and 112 HFE C282Y homozygotes from Sweden. Only variant rs236918 in the PCSK7 gene (proprotein convertase subtilisin/kexin type 7) was associated with cirrhosis or advanced fibrosis (P = 1.02 × 10−5) in the German cohort with genotypic odds ratios of 3.56 (95% CI 1.29-9.77) for CG heterozygotes and 5.38 (95% CI 2.39-12.10) for C allele carriers. Association between rs236918 and cirrhosis was confirmed in Austrian/Swiss HFE C282Y homozygotes (P = 0.014; ORallelic = 1.82 (95% CI 1.12-2.95) but not in Swedish patients. Post hoc combined analyses of German/Swiss/Austrian patients with available liver histology (N = 244, P = 0.00014, ORallelic = 2.84) and of males only (N = 431, P = 2.17 × 10−5, ORallelic = 2.54) were consistent with the premier finding. Association between rs236918 and cirrhosis was not confirmed in alcoholic cirrhotics, suggesting specificity of this genetic risk factor for HH. PCSK7 variant rs236918 is a risk factor for cirrhosis in HH patients homozygous for the HFE C282Y mutatio

Evaluation of genome-wide loci of iron metabolism in hereditary hemochromatosis identifies PCSK7 as a host risk factor of liver cirrhosis

Genome-wide association studies (GWAS) have revealed genetic determinants of iron metabolism, but correlation of these with clinical phenotypes is pending. Homozygosity for HFE C282Y is the predominant genetic risk factor for hereditary hemochromatosis (HH) and may cause liver cirrhosis. However, this genotype has a low penetrance. Thus, detection of yet unknown genetic markers that identify patients at risk of developing severe liver disease is necessary for better prevention. Genetic loci associated with iron metabolism (TF, TMPRSS6, PCSK7, TFR2 and Chr2p14) in recent GWAS and liver fibrosis (PNPLA3) in recent meta-analysis were analyzed for association with either liver cirrhosis or advanced fibrosis in 148 German HFE C282Y homozygotes. Replication of associations was sought in additional 499 Austrian/Swiss and 112 HFE C282Y homozygotes from Sweden. Only variant rs236918 in the PCSK7 gene (proprotein convertase subtilisin/kexin type 7) was associated with cirrhosis or advanced fibrosis (P = 1.02 × 10(-5)) in the German cohort with genotypic odds ratios of 3.56 (95% CI 1.29-9.77) for CG heterozygotes and 5.38 (95% CI 2.39-12.10) for C allele carriers. Association between rs236918 and cirrhosis was confirmed in Austrian/Swiss HFE C282Y homozygotes (P = 0.014; ORallelic = 1.82 (95% CI 1.12-2.95) but not in Swedish patients. Post hoc combined analyses of German/Swiss/Austrian patients with available liver histology (N = 244, P = 0.00014, ORallelic = 2.84) and of males only (N = 431, P = 2.17 × 10(-5), ORallelic = 2.54) were consistent with the premier finding. Association between rs236918 and cirrhosis was not confirmed in alcoholic cirrhotics, suggesting specificity of this genetic risk factor for HH. PCSK7 variant rs236918 is a risk factor for cirrhosis in HH patients homozygous for the HFE C282Y mutation

Antibiosis of Necrotizing Pancreatitis

Background: Necrotizing pancreatitis is a life-threatening presentation of acute pancreatitis. The mortality of 20–80% initially depends on the persistence of organ failure and systemic inflammatory response syndrome (SIRS) and, in the later course of the disease, on secondary infection of the necrosis. The questions whether prophylactic antibiotics aiming to prevent this infection should be administered and which antibiotic is the best to use, as well as the problem of fungal infection under antibiotic treatment are still intriguing and insufficiently solved. Methods: A search of the literature using PubMed was carried out, supplemented by a review of the programmes of the Digestive Disease Week (DDW) and the United European Gastroenterology Week (UEGW). Results: Despite the widely practised prophylactic antibiotic administration in severe pancreatitis, no evidence for the benefit of this strategy exists. One of the drawbacks might be a tendency for disastrous fungal infection under prophylactic antibiotics. Bacterial translocation from the gut in the second week after the onset of symptoms is the major source for infection of pancreatic necrosis and provides a clear indication for antibiotic treatment. However, routine fine-needle aspiration for a calculated antibiotic therapy cannot be recommended, and all other tests offer only indirect signs. Important factors such as enteral versus parenteral feeding and the method of necrosectomy are mostly neglected in the trials but seem to be essential for the outcome of the patient. Conclusions: Even though most meta-analyses including the newer double-blind, placebo-controlled trials on prophylactic antibiotics showed no beneficial effects in the prevention of infection of necrosis and/or outcome of the patients, this strategy is still widely used in clinical routine. Since nearly all trials published so far show systematic problems (i.e. inaccurate definition of the severity of the disease, poor statistical testing, and neglect of differences in the route of nutrition), there is a need for randomized controlled prospective trials with exact definitions of the disease.Hintergrund: Die nekrotisierende Pankreatitis weist eine Mortalität von 20–80% auf. Initial ist vor allem das Ausmaß des Organversagens entscheidend für die Prognose des Patienten. In der zweiten Krankheitswoche stellt dann die sekundäre Infektion der Nekrosen durch die Translokation von Darmkeimen das entscheidende Problem dar. Zur Vermeidung einer solchen Infektion werden klinisch sehr häufig Breitspektrumantibioktika prophylaktisch eingesetzt. Dies wird aber zunehmend kritisch diskutiert, und es existieren kontroverse Empfehlungen. Methoden: Eine Literaturrecherche unter Einbeziehung von PubMed und der Programme der Digestive Disease Week (DDW) und der United European Gastroenterology Week (UEGW) wurde durchgeführt. Ergebnisse: Die meisten Studien können den prophylaktischen Einsatz von Antibiotika bei der schweren Pankreatitis nicht rechtfertigen. Einige Studien belegen vielmehr eine Selektion resistenter Keime und vor allem auch eine erhöhte Rate von schwer therapierbaren Pilzinfektionen unter einer solchen Therapie. Daher sollte erst nach dem Nachweis einer Nekroseinfektion mit einer Antibiotikatherapie begonnen werden, wobei keine Routine-Feinnadelpunktion der Nekrose zum Keimnachweis durchgeführt werden sollte. Es stehen daher nur indirekte, meist bildgebende Verfahren für den Infektionsnachweis zur Verfügung. Entscheidende Faktoren wie die enterale Ernährung und die Methode der Nekrosektomie wurden bisher bei den meisten Studien vernachlässigt, scheinen aber essenziell für das Behandlungsergebnis des Patienten zu sein. Schlussfolgerungen: Die meisten publizierten Studien weisen eine sehr heterogene Definition der Erkrankung, uneinheitliche Behandlungsprotokolle und Ungenauigkeiten bei der statistischen Testung auf. Gerade entscheidende Faktoren wie die enterale Ernährung werden größtenteils komplett vernachlässigt. Es besteht daher ein Bedarf für randomisierte placebokontrollierte Studien, die diese Probleme berücksichtigen und suffiziente Schlussfolgerungen zur Antibiotikatherapie der schweren Pankreatitis zulassen

TRAIL/NF-κB/CX3CL1 Mediated Onco-Immuno Crosstalk Leading to TRAIL Resistance of Pancreatic Cancer Cell Lines

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignant neoplasms and registers rising death rates in western countries. Due to its late detection in advanced stages, its extremely aggressive nature and the minimal effectiveness of currently available therapies, PDAC is a challenging problem in the clinical field. One characteristic of PDAC is a distinct desmoplasia consisting of fibroblasts, endothelial and immune cells as well as non-cellular components, contributing to therapy resistance. It is well established that the NF-κB signaling pathway controls inflammation, cancer progression and apoptosis resistance in PDAC. This study attempts to identify NF-κB target genes mediating therapy resistance of humane PDAC cell lines towards death ligand induced apoptosis. By using a genome wide unbiased approach the chemokine CX3CL1 was established as a central NF-κB target gene mediating therapy resistance. While no direct impact of CX3CL1 expression on cancer cell apoptosis was identified in co-culture assays it became apparent that CX3CL1 is acting in a paracrine fashion, leading to an increased recruitment of inflammatory cells. These inflammatory cells in turn mediate apoptosis resistance of PDAC cells. Therefore, our data dissect a bifunctional cross-signaling pathway in PDAC between tumor and immune cells giving rise to therapy resistance

A targeted analysis reveals relevant shifts in the methylation and transcription of genes responsible for bile acid homeostasis and drug metabolism in non-alcoholic fatty liver disease

Background: Non-alcoholic fatty liver disease (NAFLD) is associated with a high risk for liver cirrhosis and cancer. Recent studies demonstrate that NAFLD significantly impacts on the genome wide methylation and expression reporting top hit genes to be associated with e.g. diabetes mellitus. In a targeted analysis we specifically investigate to what extent NAFLD is associated with methylation and transcriptional changes in gene networks responsible for drug metabolism (DM) and bile acid (BA) homeostasis, which may trigger liver and system toxic events. Methods: We performed a systematic analysis of 73 genes responsible for BA homeostasis and DM based on liver derived methylation and expression data from three cohort studies including 103 NAFLD and 75 non-NAFLD patients. Using multiple linear regression models, we detected methylation differences in proximity to the transcriptional start site of these genes in two NAFLD cohorts and correlated the methylation of significantly changed CpG sites to transcriptional expression in a third cohort using robust multiple linear regression approaches. Results: We detected 64 genes involved in BA homeostasis and DM to be significantly differentially methylated. In 26 of these genes, methylation significantly correlated with RNA expression, detecting i.e. genes such as CYP27A1, OST alpha, and SLC27A5 (BA homeostasis), and SLCO2B1, SLC47A1, and several UGT and CYP genes (DM) to be NAFLD dependently modulated. Conclusions: NAFLD is associated with significant shifts in the methylation of key genes responsible for BA and DM that are associated with transcriptional modulations. These findings have implications for BA composition, BA regulated metabolic pathways and for drug safety and efficacy

Obesity accelerates epigenetic aging of human liver

Because of the dearth of biomarkers of aging, it has been difficult to test the hypothesis that obesity increases tissue age. Here we use a novel epigenetic biomarker of aging (referred to as an “epigenetic clock”) to study the relationship between high body mass index (BMI) and the DNA methylation ages of human blood, liver, muscle, and adipose tissue. A significant correlation between BMI and epigenetic age acceleration could only be observed for liver (r = 0.42, P = 6.8 × 10(−4) in dataset 1 and r = 0.42, P = 1.2 × 10(−4) in dataset 2). On average, epigenetic age increased by 3.3 y for each 10 BMI units. The detected age acceleration in liver is not associated with the Nonalcoholic Fatty Liver Disease Activity Score or any of its component traits after adjustment for BMI. The 279 genes that are underexpressed in older liver samples are highly enriched (1.2 × 10(−9)) with nuclear mitochondrial genes that play a role in oxidative phosphorylation and electron transport. The epigenetic age acceleration, which is not reversible in the short term after rapid weight loss induced by bariatric surgery, may play a role in liver-related comorbidities of obesity, such as insulin resistance and liver cancer

Metabolomic tissue signature in human non-alcoholic fatty liver disease identifies protective candidate metabolites

Background Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disorder in industrialized countries, yet its pathophysiology is incompletely understood. Small-molecule metabolite screens may offer new insights into disease mechanisms and reveal new treatment targets. Methods Discovery (N = 33) and replication (N = 66) of liver biopsies spanning the range from normal liver histology to non-alcoholic steatohepatitis (NASH) were ascertained ensuring rapid freezing under 30 s in patients. 252 metabolites were assessed using GC/MS. Replicated metabolites were evaluated in a murine high-fat diet model of NAFLD. Results In a two-stage metabolic screening, hydroquinone (HQ, pcombined = 3.0 × 10−4) and nicotinic acid (NA, pcombined = 3.9 × 10−9) were inversely correlated with histological NAFLD severity. A murine high-fat diet model of NAFLD demonstrated a protective effect of these two substances against NAFLD: Supplementation with 1% HQ reduced only liver steatosis, whereas 0.6% NA reduced both liver fat content and serum transaminase levels and induced a complex regulatory network of genes linked to NALFD pathogenesis in a global expression pathway analysis. Human nutritional intake of NA equivalent was also consistent with a protective effect of NA against NASH progression. Conclusion This first small-molecular screen of human liver tissue identified two replicated protective metabolites. Either the use of NA or targeting its regulatory pathways might be explored to treat or prevent human NAFLD