Martina Sombetzki

Farnesoid X Receptor Critically Determines the Fibrotic Response in Mice but Is Expressed to a Low Extent in Human Hepatic Stellate Cells and Periductal Myofibroblasts

The nuclear bile acid receptor, farnesoid X receptor (FXR), may play a pivotal role in liver fibrosis. We tested the impact of genetic FXR ablation in four different mouse models. Hepatic fibrosis was induced in wild-type and FXR knock-out mice (FXR(-/-)) by CCl(4) intoxication, 3,5-diethoxycarbonyl-1,4-dihydrocollidine feeding, common bile duct ligation, or Schistosoma mansoni (S.m.)-infection. In addition, we determined nuclear receptor expression levels (FXR, pregnane X receptor (PXR), vitamin D receptor, constitutive androstane receptor (CAR), small heterodimer partner (SHP)) in mouse hepatic stellate cells (HSCs), portal myofibroblasts (MFBs), and human HSCs. Cell type-specific FXR protein expression was determined by immunohistochemistry in five mouse models and prototypic human fibrotic liver diseases. Expression of nuclear receptors was much lower in mouse and human HSCs/MFBs compared with total liver expression with the exception of vitamin D receptor. FXR protein was undetectable in mouse and human HSCs and MFBs. FXR loss had no effect in CCl(4)-intoxicated and S.m.-infected mice, but significantly decreased liver fibrosis of the biliary type (common bile duct ligation, 3,5-diethoxycarbonyl-1,4-dihydrocollidine). These data suggest that FXR loss significantly reduces fibrosis of the biliary type, but has no impact on non-cholestatic liver fibrosis. Since there is no FXR expression in HSCs and MFBs in liver fibrosis, our data indicate that these cells may not represent direct therapeutic targets for FXR ligands.

Schistosoma mansoni: Schistosomicidal effect of mefloquine and primaquine in vitro

We investigated the effects of the anti-malarials mefloquine and primaquine against the juvenile and adult life stages of Schistosoma mansoniin vitro. Cercariae were incubated with 0.5 μg/ml, 1 μg/ml and 2 μg/ml mefloquine or primaquine and with 1 μg/ml praziquantel for 12h. Schistosomula, pre-adults and adults were incubated with 0.5 μg/ml, 1 μg/ml and 2 μg/ml mefloquine or primaquine and with 1 μg/ml praziquantel for 7 days. The viability status was classified as viable, damaged or dead and was checked every 3h for cercariae and every 12h for schistosomula, pre-adults and adults. Both, mefloquine and primaquine show time and dose-dependent schistosomicidal effects on the four life stages of S. mansoni. The promising in vitro effects on all stages of the blood fluke S. mansoni warrants further evaluation of both anti-malarials and their derivatives for their prophylactic and therapeutic values in early and late schistosomiasis in field trials.

24-nor-ursodeoxycholic acid ameliorates inflammatory response and liver fibrosis in a murine model of hepatic Schistosomiasis

Graphical abstract

Imbalance of pro- and antifibrogenic genes and bile duct injury in murine Schistosoma mansoni infection–induced liver fibrosis

Objectives  The murine model of Schistosoma mansoni infection is characterized by strong fibrosis and little hepatocellular injury. The objective of this study was to evaluate the potential link between hepatic schistosomiasis and bile duct injury in relation to the expression of profibrotic cytokines and fibrosis‐related genes.

Vector‐mediated microRNA‐21 silencing ameliorates granulomatous liver fibrosis in Schistosoma japonicum infection

T he liver is a solid immune regulatory organ and, more than other organs, able to manage persistent damage by wound healing and tissue repair with a unique self-regenerative capacity. As a consequence of sustained liver damage, hepatic wound healing results in fibrosis, which involves effector cell–coordinated and generegulated processes. The main causes for hepatic fibrosis in industrialized countries include viral hepatitis (hepatitis B and C viruses), alcohol abuse, nonalcoholic steatohepatitis, autoimmune hepatitis, primary biliary cirrhosis, and primary sclerosing cholangitis, whereas Schistosoma spp. infection, which results in granulomatous liver fibrosis, is most prevalent in developing countries. Fibrotic scarring (production of extracellular matrix) has been shown to protect hepatocytes from toxic insults but carries the risk of dysregulated excessive matrix deposition in case of persisting hepatic injury. This results in cirrhotic changes and their clinical sequels as well as hepatocellular carcinoma. Therefore, there is an urgent need for highly effective antifibrotic drugs that are able to impede fibrosis progression and possibly promote fibrosis regression. However, as manifold as the reasons for liver injury, as diverse are the regulatory responses leading to hepatic fibrosis. It is generally accepted that liver injury (apoptosis or necrosis of hepatocytes and cholangiocytes) leads to secretion of proinflammatory cytokines such as tumor necrosis factor-a, interleukin (IL)-6, and IL-1b and the recruitment of phagocytic leukocytes and hepatic stellate cells (HSCs) as main producers of extracellular matrix. The HSCs are transactivated after phagocytosis of apoptotic hepatocytes or by inflammatory mediators such as platelet-derived growth factor, transforming growth factor-b (TGF-b), and IL-13 released by activated immune cells. Because the progression of fibrosis is generally related to the extent of inflammation and the duration of liver damage, most antifibrotic efforts target the inflammatory response or the removal of pathogenic stimuli. Although several potential substances have been investigated so far, only a few of them have provided direct antifibrotic efficacy, like hydrophilic bile acids, such as ursodeoxycholic acid, for the treatment of primary biliary cirrhosis and its side chain–shortened derivative, 24-nor-ursodeoxycholic acid, which has been shown to have a beneficial effect in mouse models of primary sclerosing cholangitis and Schistosoma mansoni infection. Intestinal schistosomiasis displays a special type of liver fibrosis. Five species of the digenetic trematode Schistosoma are known to infect humans. Of these, S. mansoni, S. japonicum, S. intercalatum, and S. mekongi predominantly affect the gastrointestinal tract. Adult worms reside within the mesenteric veins and produce numerous eggs per day. Eggs are mainly translocated into the gut by penetrating the vessel and the gut wall by local inflammation, but up to one-third of the eggs are flushed to the liver. Here they become entrapped within the small presinusoids and provoke infiltration with inflammatory cells and granulomatous lesions leading to hepatic fibrosis. In contrast to other chronic liver diseases, liver injury in schistosomiasis displays a delayed type of hypersensitivity reaction and results in relatively higher amounts of matrix deposits but with a comparatively low risk of developing cirrhosis or hepatocellular carcinoma. Tissue-entrapped parasitic eggs cause sustained liver injury and provoke a vigorous granulomatous response with an early transient Th1 response with secretion of proinflammatory cytokines, such as IL-1b, IL-12, tumor necrosis factor-a, and interferon-c. During the chronic stage of infection, the onset of egg deposition is followed by a continuous Th2mediated reaction, which is characterized by a profibrotic cytokine profile with the secretion of IL-4, IL-5, IL-10, and IL-13 and the production of immunoglobulin E. In addition, the profibrotic Th2 milieu promotes the alternative activation of macrophages that are able to regulate granulomatous inflammation. Antihelminthic treatment Abbreviations: HSC, hepatic stellate cell; IL, interleukin; miRNA, microRNA; SMAD, mothers against decapentaplegic; TGF-b, transforming growth factor-b. Address reprint requests to: Emil C. Reisinger, M.D., M.B.A., Professor and Chair of Tropical Medicine and Infectious Diseases, Department of Internal Medicine II, Rostock University Medical Center, Ernst-Heydemann Strasse 6, D-18057 Rostock, Germany. E-mail: emil.reisinger@uni-rostock.de; Tel: 149(0)381/494-7511; Fax: 149(0)381/494-7509. Copyright VC 2015 by the American Association for the Study of Liver Diseases. View this article online at wileyonlinelibrary.com. DOI 10.1002/hep.27748 Potential conflict of interest: Nothing to report

Biosensor for Hepatocellular Injury Corresponds to Experimental Scoring of Hepatosplenic Schistosomiasis in Mice

Severe hepatosplenic injury of mansonian schistosomiasis is caused by Th2 mediated granulomatous response against parasite eggs entrapped within the periportal tissue. Subsequent fibrotic scarring and deformation/sclerosing of intrahepatic portal veins lead to portal hypertension, ascites, and oesophageal varices. The murine model of Schistosoma mansoni (S. mansoni) infection is suitable to establish the severe hepatosplenic injury of disease within a reasonable time scale for the development of novel antifibrotic or anti-infective strategies against S. mansoni infection. The drawback of the murine model is that the material prepared for complex analysis of egg burden, granuloma size, hepatic inflammation, and fibrosis is limited due to small amounts of liver tissue and blood samples. The objective of our study was the implementation of a macroscopic scoring system for mice livers to determine infection-related organ alterations of S. mansoni infection. In addition, an in vitro biosensor system based on the detection of hepatocellular injury in HepG2/C3A cells following incubation with serum of moderately (50 S. mansoni cercariae) and heavily (100 S. mansoni cercariae) infected mice affirmed the value of our scoring system. Therefore, our score represents a valuable tool in experimental schistosomiasis to assess severity of hepatosplenic schistosomiasis and reduce animal numbers by saving precious tissue samples.

Single-sex infection with female Schistosoma mansoni cercariae mitigates hepatic fibrosis after secondary infection

Background Infection with Schistosoma spp. affects more than 258 million people worldwide. Current treatment strategies are mainly based on the anthelmintic Praziquantel, which is effective against adult worms but neither prevents re-infection nor cures severe liver damage. The best long-term strategy to control schistosomiasis may be to develop an immunization. Therefore, we designed a two-step Schistosoma mansoni infection model to study the immune-stimulating effect of a primary infection with either male or female cercariae, measured on the basis of TH1/TH2-response, granuloma size and hepatic fibrosis after a secondary bisexual S. mansoni challenge. Methodology/Principle findings As a first step, mice were infected with exclusively female, exclusively male, or a mixture of male and female S. mansoni cercariae. 11 weeks later they were secondarily infected with male and female S. mansoni cercariae. At week 19, infection burden, granuloma size, collagen deposition, serum cytokine profiles and the expression of inflammatory genes were analyzed. Mice initially infected with female S. mansoni cercariae displayed smaller hepatic granulomas, livers and spleens, less hepatic fibrosis and higher expression of Ctla4. In contrast, a prior infection with male or male and female S. mansoni did not mitigate disease progression after a bisexual challenge. Conclusions/Significance Our findings provide evidence that an immunization against S. mansoni is achievable by exploiting gender-specific differences between schistosomes.

Neointimal fibrotic lead encapsulation – Clinical challenges and demands for implantable cardiac electronic devices

Every tenth patient with a cardiac pacemaker or implantable cardioverter-defibrillator implanted is expected to have at least one lead problem in his lifetime. However, transvenous leads are often difficult to remove due to thrombotic obstruction or extensive neointimal fibrotic ingrowth. Despite its clinical significance, knowledge on lead-induced vascular fibrosis and neointimal lead encapsulation is sparse. Although leadless pacemakers are already available, their clinical operating range is limited. Therefore, lead/tissue interactions must be further improved in order to improve lead removals in particular. The published data on the coherences and issues related to lead associated vascular fibrosis and neointimal lead encapsulation are reviewed and discussed in this paper.

Pneumocystis pneumonia (PCP) and Pneumocystis jirovecii carriage in renal transplantation patients: a single-centre experience

SummaryBackgroundThe Pneumocystis pneumonia is an increasing problem in transplanted patients: up to 25 % suffer from Pneumocystis pneumonia, occurring during the first 6 months after transplantation.MethodsFrom 2001 to 2009, we investigated 21 patients with pneumonia after renal transplantation for the presence of Pneumocystis jirovecii. The laboratory diagnosis was established by Grocott and Giemsa staining methods and Pneumocystis-specific mitochondrial transcribed large subunit nested polymerase chain reaction (PCR). The PCR was also used for the differentiation of Pneumocystis pneumonia from Pneumocystis carriage.ResultsOf 21 patients, 7 had a Pneumocystis pneumonia, 6 were Pneumocystis carriers and 8 patients were negative. Four out of seven Pneumocystis pneumonia patients and two out of six patients with Pneumocystis carriage had a delayed graft function. An acute cytomegalovirus infection after transplantation was not detectable in the patients with Pneumocystis pneumonia, but in three patients with Pneumocystis carriage.ConclusionsPneumocystis pneumonia was present in 33.3 % of transplanted patients with suspected pneumonia. An association between acute rejection or co-infections and Pneumocystis pneumonia or carriage in patients after renal transplantation cannot be excluded. In three out of seven Pneumocystis pneumonia patients, an overlapping of hospitalisation times and an onset of Pneumocystis pneumonia 6 months after transplantation was found. Thus, person-to-person transmission seems probable in these cases.ZusammenfassungHintergrundDie Pneumocystis Pneumonie stellt in zunehmendem Maße ein Problem bei Patienten nach Transplantationen dar: bis zu 25 % der Patienten erkranken an einer Pneumocystis Pneumonie, die innerhalb der ersten sechs Monate nach Transplantation auftritt.MethodikVon 2001 bis 2009 wurde bei 21 Patienten nach Nierentransplantation eine Pneumonie durch Pneumocystis jirovecii vermutet. Die Labordiagnostik erfolgte mittels Grocott- und Giemsa-Färbungen sowie Pneumocystis-spezifischer „mitochondrial transcribed large subunit“ nested PCR. Diese PCR wurde zusätzlich zur Differenzierung zwischen einer Pneumocystis Pneumonie und einer Pneumocystis Besiedelung genutzt.ErgebnisseBei 7/21 Patienten wurde eine Pneumocystis Pneumonie nachgewiesen, 6 waren mit Pneumocystis besiedelt und 8 Patienten waren negativ. 4/7 Pneumocystis Pneumonie Patienten sowie 2/6 Patienten mit Pneumocystis Besiedlung hatten eine verzögerte Transplantat-Funktion. Eine akute Cytomegalie-Virus-Infektion nach Transplantation trat bei keinem der Pneumocystis Pneumonie-Fälle und bei drei Patienten mit Pneumocystis Besiedelung auf.SchlussfolgerungenEine Pneumocystis Pneumonie konnte bei 33,3 % der Patienten nach Nierentransplantation und Verdacht auf Pneumonie nachgewiesen werden. Eine Assoziation zwischen akuter Rejektion oder Koinfektionen und dem Auftreten einer PCP bzw. Besiedelung war nicht auszuschließen. Bei 3/7 Pneumocystis Pneumonie Patienten wurde eine Überschneidung der Hospitalisierungs-Zeiträume mit gleichzeitigem Beginn der Pneumocystis Pneumonie sechs Monate nach Transplantation festgestellt. Eine Übertragung von Person zu Person scheint in diesen Fällen sehr wahrscheinlich.

Host defense versus immunosuppression: Male and female Schistosoma mansoni differentially impact the host’s immune system

Schistosomiasis remains a major cause of morbidity and mortality, and in the tropics and subtropics, in particular, infection rates are high [ref:1]. The efficacy of anthelmintic therapy is limited since it has no effect on immature parasite stages and does not prevent re-infection. The root[for full text, please go to the a.m. URL]