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Dive into the research topics where Paul Manka is active.

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Featured researches published by Paul Manka.


Digestion | 2009

Hepatitis B-Associated Acute Liver Failure: Immediate Treatment with Entecavir Inhibits Hepatitis B Virus Replication and Potentially Its Sequelae

Christoph Jochum; Isabella Gawlista; A. Fiedler; Paul Manka; Fuat H. Saner; Michael Roggendorf; Guido Gerken; Ali Canbay

Background: Acute hepatitis B virus (HBV) infection is followed by high viral replication rates leading to hepatocyte death and ultimately, in some cases, to acute liver failure (ALF) necessitating liver transplantation. Thus, the objective of treating HBV-induced ALF is to eliminate or significantly suppress HBV replication. Methods/Results: This prospective study (02/2008–02/2009) included 6 patients (1 female and 5 males, median age 35.5 years). HBV DNA and hepatitis B surface antigen (HBsAg) levels were detected, and hepatocyte death was quantified in patients’ sera by (a) M65 ELISA and (b) M30 ELISA. All patients received entecavir treatment at 1 mg daily within 1–18 days after admission. Upon treatment, pathologic parameters rapidly decreased and returned to normal values or trace amounts (HBV DNA) within 3 months in all of the cases. A seroconversion to anti-HBsAg was achieved in 5 out of 6 patients; one patient with late onset of treatment did not seroconvert. M65 and the difference of M65-M30 as a marker for cell necrosis dropped significantly within 1 week of treatment. Conclusion: This preliminary series of 6 patients reveals that immediate treatment of HBV-induced ALF with entecavir is well tolerated and beneficially affects the course of the disease.


Clinical Gastroenterology and Hepatology | 2015

Hepatitis E Virus Infection as a Possible Cause of Acute Liver Failure in Europe

Paul Manka; Lars P. Bechmann; Jason D. Coombes; Viktoria Thodou; Martin Schlattjan; Alisan Kahraman; Wing-Kin Syn; Fuat H. Saner; Guido Gerken; Hideo Baba; Jens Verheyen; Jörg Timm; Ali Canbay

BACKGROUND & AIMS In Western countries, infection with the hepatitis E virus (HEV) is considered to be rare and imported from endemic regions. However, the prevalence of HEV infection has increased among adults in central Europe. HEV infection can cause acute liver failure (ALF), but there have been only a few confirmed cases of HEV-associated ALF in Europe. We investigated the number of cases of indeterminate ALF associated with HEV infection. METHODS We performed a retrospective analysis of 80 patients diagnosed with ALF or acute hepatitis at the University Hospital Essen in Germany from November 2006 through December 2013. Clinical data were collected from the hospital databases; archived sera were tested for IgG and IgM against HEV, as well as HEV RNA. RESULTS Sera from 12 patients (15%) tested positive for IgG against HEV IgG; 7 of these samples did not test positive for HEV IgM or HEV RNA. Sera from 64 patients (80%) did not test positive for IgG or IgM against HEV or HEV RNA. Sera from 8 patients (10%) tested positive for HEV RNA (only 4 of these were positive for HEV IgG) and had clinical findings to support acute HEV infection. CONCLUSIONS In a hospital in Germany, approximately 10% to 15% of patients with ALF had evidence for HEV infection. Serologic tests for IgG against HEV are insufficient to identify or exclude HEV infection; tests for HEV RNA also should be performed on patients with ALF of ambiguous etiology.


Frontiers in Physiology | 2013

Role of liver progenitors in acute liver injury.

Jan Best; Laurent Dollé; Paul Manka; Jason D. Coombes; Leo A. van Grunsven; Wing-Kin Syn

Acute liver failure (ALF) results from the acute and rapid loss of hepatocyte function and frequently exhibits a fulminant course, characterized by high mortality in the absence of immediate state-of-the-art intensive care and/or emergency liver transplantation (ELT). The role of hepatocyte-mediated liver regeneration during acute and chronic liver injury has been extensively investigated, and recent studies suggest that hepatocytes are not exclusively responsible for the regeneration of the injured liver during fulminant liver injury. Liver progenitor cells (LPC) (or resident liver stem cells) are quiescent in the healthy liver, but may be activated under conditions where the regenerative capacity of mature hepatocytes is severely impaired. This review aims to provide an overview of the role of the LPC population during ALF, and the role of putative cytokines, growth factors, mitogens, and hormones in the LPC response. We will highlight the potential interaction among cellular compartments during ALF, and discuss the possible prognostic value of the LPC response on ALF outcomes.


Scientific Reports | 2015

Normal liver enzymes are correlated with severity of metabolic syndrome in a large population based cohort.

Julia Kälsch; Lars P. Bechmann; Dominik Heider; Jan Best; Paul Manka; Hagen Kälsch; Jan-Peter Sowa; Susanne Moebus; Uta Slomiany; Karl-Heinz Jöckel; Raimund Erbel; Guido Gerken; Ali Canbay

Key features of the metabolic syndrome are insulin resistance and diabetes. The liver as central metabolic organ is not only affected by the metabolic syndrome as non-alcoholic fatty liver disease (NAFLD), but may contribute to insulin resistance and metabolic alterations. We aimed to identify potential associations between liver injury markers and diabetes in the population-based Heinz Nixdorf RECALL Study. Demographic and laboratory data were analyzed in participants (n = 4814, age 45 to 75y). ALT and AST values were significantly higher in males than in females. Mean BMI was 27.9 kg/m2 and type-2-diabetes (known and unkown) was present in 656 participants (13.7%). Adiponectin and vitamin D both correlated inversely with BMI. ALT, AST, and GGT correlated with BMI, CRP and HbA1c and inversely correlated with adiponectin levels. Logistic regression models using HbA1c and adiponectin or HbA1c and BMI were able to predict diabetes with high accuracy. Transaminase levels within normal ranges were closely associated with the BMI and diabetes risk. Transaminase levels and adiponectin were inversely associated. Re-assessment of current normal range limits should be considered, to provide a more exact indicator for chronic metabolic liver injury, in particular to reflect the situation in diabetic or obese individuals.


Hepatobiliary surgery and nutrition | 2015

Role of liver progenitors in liver regeneration.

Jan Best; Paul Manka; Wing-Kin Syn; Laurent Dollé; Leo A. van Grunsven; Ali Canbay

During massive liver injury and hepatocyte loss, the intrinsic regenerative capacity of the liver by replication of resident hepatocytes is overwhelmed. Treatment of this condition depends on the cause of liver injury, though in many cases liver transplantation (LT) remains the only curative option. LT for end stage chronic and acute liver diseases is hampered by shortage of donor organs and requires immunosuppression. Hepatocyte transplantation is limited by yet unresolved technical difficulties. Since currently no treatment is available to facilitate liver regeneration directly, therapies involving the use of resident liver stem or progenitor cells (LPCs) or non-liver stem cells are coming to fore. LPCs are quiescent in the healthy liver, but may be activated under conditions where the regenerative capacity of mature hepatocytes is severely impaired. Non-liver stem cells include embryonic stem cells (ES cells) and mesenchymal stem cells (MSCs). In the first section, we aim to provide an overview of the role of putative cytokines, growth factors, mitogens and hormones in regulating LPC response and briefly discuss the prognostic value of the LPC response in clinical practice. In the latter section, we will highlight the role of other (non-liver) stem cells in transplantation and discuss advantages and disadvantages of ES cells, induced pluripotent stem cells (iPS), as well as MSCs.


Digestion | 2016

Spleen and Liver Stiffness Is Positively Correlated with the Risk of Esophageal Variceal Bleeding

Matthias Buechter; Alisan Kahraman; Paul Manka; Guido Gerken; Christoph Jochum; Ali Canbay; Alexander Dechêne

Background/Aims: Portal hypertension (PH) is a common complication of chronic liver disease and results in esophageal and gastric variceal bleeding, which is associated with a high mortality rate. Measurement of the hepatic venous pressure gradient (HVPG) is considered the gold standard for diagnosing PH and estimating the risk of varices and bleeding. In contrast, upper gastrointestinal (GI) endoscopy (UGE) can reliably demonstrate the presence of varices and bleeding. Both measures are invasive, and HVPG is mainly restricted to tertiary centers. Therefore, the development of noninvasive methods of assessing the severity of PH and the risk of variceal bleeding is warranted. Methods: We retrospectively examined the correlation of spleen stiffness (SSM) and liver stiffness measurements (LSM) with the incidence of variceal bleeding among 143 patients who underwent combined liver and spleen elastography between 2013 and 2015. Results: For 19 of 103 patients (16.8%), upper GI variceal bleeding was diagnosed and treated endoscopically. The median SSM of all patients was 35.3 kilopascals (kPa); the median LSM, 11.7 kPa. Patients with previous bleeding episodes had significantly higher SSM (75.0 kPa) and LSM (37.3 kPa) than those without a history of bleeding (SSM, 30.6 kPa; LSM, 8.2 kPa; p < 0.0001). Seventy-five patients (66.4%) underwent UGE in addition to SSM and LSM: 25 with no esophageal varices (EVs; SSM, 29.5 kPa; LSM, 11.4 kPa), 16 with EV grade 1 (SSM, 35.9 kPa; LSM, 33.4 kPa), 21 with EV grade 2 (SSM, 67.8 kPa; LSM, 27.0 kPa) and 13 with EV grade 3 (SSM, 75.0 kPa; LSM, 26.3 kPa). No statistically significant differences were found between respective grades of EV but were found between the presence and absence of varices. At a calculated cutoff level of 42.6 kPa (with application of 95% CI), SSM had sensitivity of 89% and specificity of 64% in determining the risk of bleeding, with a negative predictive value (NPV) of 0.97 (LSM sensitivity, 84%; LSM specificity, 80%; LSM NPV, 0.96 at LSM cutoff level of 20.8 kPa). When LSM (cutoff level, 20.8 kPa) and SSM (cutoff level, 42.6 kPa) were combined, the NPV was 1 (sensitivity, 100%; specificity, 55%). Conclusion: SSM and LSM as determined by FibroScan (a noninvasive method of detecting PH) is positively correlated with upper GI variceal bleeding (optimal SSM cutoff level, 42.6 kPa; optimal LSM cutoff level, 20.8 kPa). No patients with both SSM and LSM below cutoff levels had a history of bleeding complications.


Biochimica et Biophysica Acta | 2016

Osteopontin is a proximal effector of leptin-mediated non-alcoholic steatohepatitis (NASH) fibrosis

Jason D. Coombes; Steven Sok Choi; Marzena Swiderska-Syn; Paul Manka; Danielle T. Reid; Elena Palma; Marco A. Briones-Orta; Guanhua Xie; Rasha Younis; Naoto Kitamura; Marco della Peruta; Shanna Bitencourt; Laurent Dollé; Ye Htun Oo; Zhiyong Mi; Paul C. Kuo; Roger Williams; S. Chokshi; Ali Canbay; Lee C. Claridge; Bertus Eksteen; Anna Mae Diehl; Wing Kin Syn

INTRODUCTION Liver fibrosis develops when hepatic stellate cells (HSC) are activated into collagen-producing myofibroblasts. In non-alcoholic steatohepatitis (NASH), the adipokine leptin is upregulated, and promotes liver fibrosis by directly activating HSC via the hedgehog pathway. We reported that hedgehog-regulated osteopontin (OPN) plays a key role in promoting liver fibrosis. Herein, we evaluated if OPN mediates leptin-profibrogenic effects in NASH. METHODS Leptin-deficient (ob/ob) and wild-type (WT) mice were fed control or methionine-choline deficient (MCD) diet. Liver tissues were assessed by Sirius-red, OPN and αSMA IHC, and qRT-PCR for fibrogenic genes. In vitro, HSC with stable OPN (or control) knockdown were treated with recombinant (r)leptin and OPN-neutralizing or sham-aptamers. HSC response to OPN loss was assessed by wound healing assay. OPN-aptamers were also added to precision-cut liver slices (PCLS), and administered to MCD-fed WT (leptin-intact) mice to determine if OPN neutralization abrogated fibrogenesis. RESULTS MCD-fed WT mice developed NASH-fibrosis, upregulated OPN, and accumulated αSMA+ cells. Conversely, MCD-fed ob/ob mice developed less fibrosis and accumulated fewer αSMA+ and OPN+ cells. In vitro, leptin-treated HSC upregulated OPN, αSMA, collagen 1α1 and TGFβ mRNA by nearly 3-fold, but this effect was blunted by OPN loss. Inhibition of PI3K and transduction of dominant negative-Akt abrogated leptin-mediated OPN induction, while constitutive active-Akt upregulated OPN. Finally, OPN neutralization reduced leptin-mediated fibrogenesis in both PCLS and MCD-fed mice. CONCLUSION OPN overexpression in NASH enhances leptin-mediated fibrogenesis via PI3K/Akt. OPN neutralization significantly reduces NASH fibrosis, reinforcing the potential utility of targeting OPN in the treatment of patients with advanced NASH.


BMC Gastroenterology | 2013

Serum sodium based modification of the MELD does not improve prediction of outcome in acute liver failure

Paul Manka; Lars P. Bechmann; Frank Tacke; Jan-Peter Sowa; Martin Schlattjan; Julia Kälsch; Christoph Jochum; Andreas Paul; Fuat H. Saner; Christian Trautwein; Guido Gerken; Ali Canbay

BackgroundAcute liver failure (ALF) is a devastating clinical syndrome with a high mortality rate. The MELD score has been implied as a prognostic tool in ALF. Hyponatremia is associated with lethal outcome in ALF. Inclusion of serum sodium (Na) into the MELD score was found to improve its predictive value in cirrhotic patients. Therefore the aim of this study was to determine whether inclusion of serum Na improves the predictive value of MELD in ALF compared to established criteria.MethodsIn a prospective single center study (11/2006–12/2010), we recruited 108 consecutive ALF patients (64% females / 36% males), who met the criteria defined by the “Acute Liver Failure Study Group Germany”. Upon admission, clinical and laboratory data were collected, King’s College Criteria (KCC), Model of End Stage Liver Disease score (MELD), and serum sodium based modifications like the MELD-Na score and the United Kingdom Model of End Stage Liver Disease score (UKELD) were calculated and area under the receiver operating characteristic curve analyses were performed regarding the prediction of spontaneous recovery (SR) or non-spontaneous recovery (NSR; death or transplantation).ResultsSerum bilirubin was of no prognostic value in ALF, and Na also failed to predict NSR in ALF. The classical MELD score was superior to sodium-based modifications and KCC.ConclusionsWe validated the prognostic value of MELD-Na and UKELD in ALF. Classic MELD score calculations performed superior to KCC in the prediction of NSR. Serum Na and Na-based modifications of MELD did not further improve its prognostic value.


Visceral medicine | 2016

Liver Failure due to Acute Viral Hepatitis (A-E).

Paul Manka; Jens Verheyen; Guido Gerken; Ali Canbay

Background: Viral hepatitis is still one of the key causes of acute liver failure (ALF) in the world. Methods: A selective literature search of the PubMed database was conducted, including current studies, reviews, meta-analyses, and guidelines. We obtained an overview of ALF due to viral hepatitis in terms of epidemiology, course, and treatment options. Results: Most fulminant viral courses are reported after infection with hepatitis A, B, and B/D, but not with hepatitis C. Hepatitis E is also known to cause ALF but has not gained much attention in recent years. However, more and more autochthonous hepatitis E virus infections have been recently observed in Europe. Reactivation of hepatitis B virus (HBV) under immunosuppressive conditions, such as after intensive chemotherapy, is also an increasing problem. For most viral-induced cases of ALF, liver transplantation represented the only therapeutic option in the past. Today, immediate treatment of HBV-induced ALF with nucleotide or nucleoside analogs is well tolerated and beneficially affects the course of the disease. Conclusion: Although numbers in Western European countries are decreasing rapidly, reliable diagnostic screening for hepatitis A-E is necessary to identify the etiology and to determine those most at risk of developing ALF.


Digestive and Liver Disease | 2018

Spleen stiffness is positively correlated with HVPG and decreases significantly after TIPS implantation

Matthias Buechter; Paul Manka; Jens M. Theysohn; Marcus Reinboldt; Ali Canbay; Alisan Kahraman

BACKGROUND Transjugular intrahepatic portosystemic shunt (TIPS) is indicated in patients with decompensated portal hypertension (PH). Hepatic venous pressure gradient (HVPG) is considered gold standard for assessment of PH. Because HVPG measurement is invasive, non-invasive methods for evaluating severity of PH are warranted. PATIENTS AND METHODS We retrospectively correlated spleen stiffness as measured by FibroScan with HVPG in patients who underwent TIPS. Twenty-four patients with spleen stiffness measurement (SSM) one day before (D-1), one day after (D+1) and 28 days after TIPS (D+28) were included. RESULTS SSM was positively correlated with pre-TIPS HVPG (HVPG <13mmHg, median SSM: 19.7±8.6kPa; HVPG 13-24mmHg, median SSM: 45.0±15.7kPa; HVPG >24mmHg, median SSM: 75.0±6.2kPa; p<0.05]; r2=0.72; p<0.001) and decreased significantly after TIPS implantation (D-1, median SSM: 67.1±17.3kPa; D+1, median SSM: 44.7±18.5kPa; D+28, median SSM: 35.6±17.0kPa; p<0.05), while liver stiffness measurement decrease was not statistically significant. CONCLUSIONS Our study highlights the utility of SSM as non-invasive tool in patients with chronic liver disease in evaluating degree of PH potentially offering a confirmable additional parameter in surveillance of patients undergoing TIPS procedure.

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Ali Canbay

Otto-von-Guericke University Magdeburg

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Guido Gerken

University of Duisburg-Essen

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Lars P. Bechmann

University of Duisburg-Essen

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Alisan Kahraman

University of Duisburg-Essen

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Wing-Kin Syn

Medical University of South Carolina

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Jason D. Coombes

Foundation for Liver Research

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Fuat H. Saner

University of Duisburg-Essen

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Roger Williams

Laboratory of Molecular Biology

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Martin Schlattjan

University of Duisburg-Essen

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Jan-Peter Sowa

Otto-von-Guericke University Magdeburg

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