Johannes Chang
University of Bonn
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Featured researches published by Johannes Chang.
Liver International | 2017
Christian Jansen; Christopher Bogs; Wim Verlinden; Maja Thiele; Philipp T. Möller; Jan Görtzen; Jennifer Lehmann; Thomas Vanwolleghem; Luisa Vonghia; Michael Praktiknjo; Johannes Chang; Aleksander Krag; Christian P. Strassburg; Sven Francque; Jonel Trebicka
Clinically significant portal hypertension (CSPH) is associated with severe complications and decompensation of cirrhosis. Liver stiffness measured either by transient elastography (TE) or Shear‐wave elastography (SWE) and spleen stiffness by TE might be helpful in the diagnosis of CSPH. We recently showed the algorithm to rule‐out CSPH using sequential liver‐ (L‐SWE) and spleen‐Shear‐wave elastography (S‐SWE). This study investigated the diagnostic value of S‐SWE for diagnosis of CSPH.
Gut | 2016
Christian Jansen; Christopher Bogs; Wim Verlinden; Maja Thiele; Philipp T. Möller; Jan Görtzen; Jennifer Lehmann; Michael Praktiknjo; Johannes Chang; Aleksander Krag; Christian P. Strassburg; Sven Francque; Jonel Trebicka
Recently, the UK guidelines on variceal bleeding1 and other reports have introduced the role of elastography for the diagnosis of oesophageal varices (OVs).2 ,3 Development of OVs is likely when the hepatic venous pressure gradient is higher than 10 mm Hg, which defines clinically significant portal hypertension (CSPH). Baveno VI implemented transient elastography (TE) as a tool to rule in CSPH in viral aetiologies and to rule out varices (need of screening endoscopy for varices).4 Furthermore, CSPH has a strong prognostic value in patients with cirrhosis. Recent studies introduced Shear-wave elastography of the liver (L-SWE) as a promising tool to diagnose portal hypertension. These studies find good diagnostic accuracy of L-SWE with specificity and sensitivity ranging around 80% and superior to TE. However, in more than 30% of the patients CSPH could not be ruled in or ruled out, since their SWE values were between the cut-offs. This prospective multicentre study investigated the …
Journal of Surgical Research | 2012
Stephan Bortscher; Johannes Chang; Tim O. Vilz; Nico Schäfer; Nils Sommer; Sven Wehner; Jörg C. Kalff; Marcus Overhaus
BACKGROUND Heme oxygenase (HO-1) protects against inflammation. In this study, we investigated the protective function of hemin-induced HO-1 against lipopolysaccharide (LPS)-induced ileus. METHODS Rats received LPS intraperitoneally 24 h after intraperitoneal hemin pretreatment or placebo. We also injected zinc protoporphyrin (ZnPP, 3rd group), an inhibitor of HO-1, intraperitoneally 2 h before LPS administration. To assess intestinal muscle function, we examined muscularis strip contractility in an organ bath and measured gastrointestinal transit in vivo. We investigated inflammation within the muscularis using polymerase chain reaction (interleukin [IL]-6, inducible nitric oxide synthase (iNOS), HO-1 and IL-10) 6 and 24 h after LPS. RESULTS Hemin significantly improved in vitro intestinal muscularis contractility (P < 0.001). In addition, hemin prevented LPS-induced dysmotility in vivo (gastrointestinal transit, geometric center: 8.39 ± 0.33 versus 5.68 ± 0.44; P < 0.001). In Zinc protoporphyrin (ZnPP)-treated animals, both parameters were significantly decreased compared with the hemin group. Messenger RNA expression demonstrated a significant reduction in IL-6 (6 h, hemin: 127.6 ± 36.7 versus LPS: 14,431 ± 5407; 24 h: 1.58 ± 0.39 versus 11.15 ± 2.59; P < 0.01) and iNOS (6 h: 2516 ± 985 versus 50,771 ± 13,321; 24 h: 55.11 ± 10.55 versus 257.1 ± 43.18; P < 0.001) in hemin-treated animals. Anti-inflammatory HO-1 messenger RNA levels (6 h, hemin: 116.3 ± 18.55 versus LPS: 26.02 ± 3.64; 24 h: 18.46 ± 2.69 versus 2.80 ± 0.32; P < 0.001) were increased. There was no significant difference in IL-10 levels at 6 and 24 h. ZnPP reversed the anti-inflammatory hemin effects. CONCLUSIONS Hemin induction of HO-1 diminishes LPS-induced sepsis. Heme oxygenase-1 has a central role in preventing sepsis-induced ileus. This benefit is reversed by HO-1 inhibition with ZnPP.
Hepatology | 2018
Michael Praktiknjo; Marius Book; Julian A. Luetkens; Alessandra Pohlmann; Carsten H. Meyer; Daniel Thomas; Christian Jansen; Andreas Feißt; Johannes Chang; Jochen Grimm; Jennifer Lehmann; Christian P. Strassburg; Juan G. Abraldes; Guido M. Kukuk; Jonel Trebicka
Muscle mass seems to be a prognostic marker in patients with liver cirrhosis. However, reported methods to quantify muscle mass are heterogeneous, consented cutoff values are missing, and most studies have used computed tomography. This study evaluated fat‐free muscle area (FFMA) as a marker of sarcopenia using magnetic resonance imaging (MRI) in patients with decompensated cirrhosis with transjugular intrahepatic portosystemic shunt (TIPS). The total erector spinae muscle area and the intramuscular fat tissue area were measured and subtracted to calculate the FFMA in 116 patients with cirrhosis by TIPS and MRI. The training cohort of 71 patients compared computed tomography–measured transversal psoas muscle thickness with FFMA. In 15 patients MRI was performed before and after TIPS, and in 12 patients follistatin serum measurements were carried out. The results on FFMA were confirmed in a validation cohort of 45 patients. FFMA correlated with follistatin and transversal psoas muscle thickness and showed slightly better association with survival than transversal psoas muscle thickness. Gender‐specific cutoff values for FFMA were determined for sarcopenia. Decompensation (ascites, overt hepatic encephalopathy) persisted after TIPS in the sarcopenia group but resolved in the nonsarcopenia group. Sarcopenic patients showed no clinical improvement after TIPS as well as higher mortality, mainly due to development of acute‐on‐chronic liver failure. FFMA was an independent predictor of survival in these patients. Conclusion: This study offers an easy‐to‐apply MRI‐based measurement of fat‐free muscle mass as a marker of sarcopenia in decompensated patients; while TIPS might improve sarcopenia and thereby survival, persistence of sarcopenia after TIPS is associated with a reduced response to TIPS and a higher risk of acute‐on‐chronic liver failure development and mortality. (Hepatology 2018;67:1014–1026)
Liver Transplantation | 2018
Christian Jansen; Alexander Cox; Robert Schueler; Matthias Schneider; Jennifer Lehmann; Michael Praktiknjo; Alessandra Pohlmann; Johannes Chang; Steffen Manekeller; Georg Nickenig; Gabriela A. Berlakovich; Christian P. Strassburg; Christoph Hammerstingl; Katharina Staufer; Jonel Trebicka
Late allocation of organs for transplant impairs post–liver transplantation (LT) survival. Cardiac dysfunction, especially diastolic and autonomic dysfunction, is frequent and plays an important role in the prognosis of patients with cirrhosis. However, the role of myocardial contractility is unexplored, and its prognostic value is controversially discussed. This study analyses the role of myocardial contractility assessed by speckle tracking echocardiography in LT allocation. In total, 168 patients with cirrhosis (training cohort, 111; validation cohort [VC], 57) awaiting LT in 2 centers were included in this retrospective study. Also, 51 patients from the training and all patients from the VC were transplanted, 36 patients of the training and 38 of the VC were alive at the end of follow‐up, and 21 nontransplanted patients died. Contractility of the left ventricle (LV) increased with severity of the Child‐Pugh score. Interestingly, higher LV contractility in the training cohort patients, especially in those with Child‐Pugh C, was an independent predictor of reduced transplant‐free survival. In male patients, the effects on survival of increased left and right ventricular myocardial contractility were more pronounced. Notably, competing risk analysis demonstrated that increased contractility is associated with earlier LT, which could be confirmed in the VC. Importantly, LV myocardial contractility had no impact on survival of patients not receiving LT or on post‐LT survival. In conclusion, this study demonstrates for the first time that increased myocardial contractility in decompensated patients identifies patients who require LT earlier, but without increased post‐LT mortality. Liver Transplantation 24 15–25 2018 AASLD.
Journal of Surgical Research | 2012
Johannes Chang; Sven Wehner; Nico Schäfer; Maria Sioutis; Stephan Bortscher; A. Hirner; Jörg C. Kalff; Anthony J. Bauer; Marcus Overhaus
BACKGROUND Active matrix metallopeptidase 9 (MMP-9) disruption of the extracellular matrix (ECM) plays an important role in inflammatory disorders. In this study, we investigated the inflammatory role of MMP-9 and the ECM breakdown product hyaluronan as a trigger for the postoperative intestinal inflammatory response of postoperative ileus. METHODS We performed a standardized intestinal surgical manipulation on rats to produce ileus assessed by the oral non-digestible fluorescein isothiocyanate-dextran transit assay. We studied isolated intestinal muscularis extracts for mRNA expressions of interleukin 6 (IL-6), MMP-9 and CD44. We quantified peritoneal MMP-9 activity using zymography, and quantified peritoneal fluid and serum for hyaluronan and tissue inhibitor of metalloproteinase 1 levels by enzyme-linked immunosorbent assay (ELISA). We cultured peritoneal macrophages and exposed them to peritoneal fluid or synthetic hyaluronan for ELISA analysis of IL-6 and macrophage inflammatory protein-1α. RESULTS Transit was significantly delayed after surgical manipulation, and extracts of the isolated jejunal and colonic muscularis demonstrated a significant induction of IL-6, MMP-9, and CD44 mRNAs compared with controls. Zymography confirmed significant MMP-9 activity in peritoneal fluid compared with controls. Enzyme-linked immunosorbent assay measurements showed a significant up-regulation in hyaluronan and tissue inhibitor of metalloproteinase 1 in the peritoneal fluid and serum. In addition, ELISA and reverse transcriptase-polymerase chain reaction measurements of peritoneal macrophages stimulated with postsurgical peritoneal fluid and synthetic hyaluronan resulted in higher expressions of IL-6 and macrophage inflammatory protein-1α in the macrophage supernatant. CONCLUSIONS Our results confirm that MMP-9 disruption in the ECM with hyaluronan release and muscularis CD44 receptor induction has the potential to trigger muscularis proinflammatory cascades that cause postoperative ileus. Matrix metallopeptidase 9 inhibition may be a novel therapeutic approach to limit postoperative ileus.
Liver Transplantation | 2017
Christian Jansen; Alexander Cox; Robert Schueler; Matthias Schneider; Jennifer Lehmann; Michael Praktiknjo; Alessandra Pohlmann; Johannes Chang; Steffen Manekeller; Georg Nickenig; Gabriela A. Berlakovich; Christian P. Strassburg; Christoph Hammerstingl; Katharina Staufer; Jonel Trebicka
Late allocation of organs for transplant impairs post–liver transplantation (LT) survival. Cardiac dysfunction, especially diastolic and autonomic dysfunction, is frequent and plays an important role in the prognosis of patients with cirrhosis. However, the role of myocardial contractility is unexplored, and its prognostic value is controversially discussed. This study analyses the role of myocardial contractility assessed by speckle tracking echocardiography in LT allocation. In total, 168 patients with cirrhosis (training cohort, 111; validation cohort [VC], 57) awaiting LT in 2 centers were included in this retrospective study. Also, 51 patients from the training and all patients from the VC were transplanted, 36 patients of the training and 38 of the VC were alive at the end of follow‐up, and 21 nontransplanted patients died. Contractility of the left ventricle (LV) increased with severity of the Child‐Pugh score. Interestingly, higher LV contractility in the training cohort patients, especially in those with Child‐Pugh C, was an independent predictor of reduced transplant‐free survival. In male patients, the effects on survival of increased left and right ventricular myocardial contractility were more pronounced. Notably, competing risk analysis demonstrated that increased contractility is associated with earlier LT, which could be confirmed in the VC. Importantly, LV myocardial contractility had no impact on survival of patients not receiving LT or on post‐LT survival. In conclusion, this study demonstrates for the first time that increased myocardial contractility in decompensated patients identifies patients who require LT earlier, but without increased post‐LT mortality. Liver Transplantation 24 15–25 2018 AASLD.
Life Sciences | 2015
Tim O. Vilz; Lisa Roessel; Johannes Chang; Dimitrios Pantelis; Timo Schwandt; Arne Koscielny; Sven Wehner; Joerg C. Kalff
AIMS Postoperative ileus (POI) is a frequent complication after abdominal surgery, resulting from an inflammation of the muscularis externa (ME). So far no valid biomarker for occurrence, duration or intensity of POI exists. Extravasation of monocytes and neutrophils from blood circulating into the postoperative ME is well known as a hallmark of POI. In a previous study we demonstrated that a low abundant subset of TH1 cells, activated by IL-12, can be detected in the peripheral blood of a small subset of patients in response to abdominal surgery. The aim of the present study was to investigate if these specific TH1 cells, IL-12 or circulating leukocyte levels could act as a valid marker for POI occurrence. MAIN METHODS At different time points, blood samples of patients undergoing abdominal or extraabdominal surgery were collected. Serum levels of IL-12 or TH1 cells as well as neutrophils and monocytes were analyzed. Data were compared between both groups and correlated with clinical signs of POI. KEY FINDINGS Time until first flatus and defecation as well as solid food tolerances are delayed after abdominal compared to extraabdominal surgery. Circulating IL-12 levels and numbers of TH1 cells, neutrophils and monocytes did not differ between both groups. SIGNIFICANCE While previous experiments indicated that specific TH1 cells play a crucial role in POI dissemination, our present data from a larger human cohort demonstrate that they do not seem to be suitable to distinguish between abdominal and extraabdominal surgery. Furthermore neither TH1 cells nor leukocytes or serum IL-12 levels are appropriate biomarkers for POI in a clinical setting.
PLOS ONE | 2018
Christian Jansen; Baravan Al-Kassou; Jennifer Lehmann; Alessandra Pohlmann; Johannes Chang; Michael Praktiknjo; Georg Nickenig; Christian P. Strassburg; Jan W. Schrickel; René Andrié; Markus Linhart; Jonel Trebicka
Background In patients with liver cirrhosis, cardiac dysfunction is frequent and is associated with increased morbidity and mortality. Cardiac dysfunction in cirrhosis seems to be linked to autonomic dysfunction. This study investigates the role of autonomic dysfunction assessed by Heart Rate Turbulence (HRT) analyses in patients with liver cirrhosis. Methods and patients Inclusion criteria was (1) diagnosis of cirrhosis by clinical, imaging or biopsy and (2) evaluation by standard 12-lead-ECG and 24h holter monitoring and (3) at least 3 premature ventricular contractions. The exclusion criterion was presence of cardiac diseases, independent of liver cirrhosis. Biochemical parameters were analysed using standard methods. HRT was assessed using Turbulence onset (TO) and slope (TS). The endpoint was deterioration of liver cirrhosis defined as increased MELD and readmission for complications of liver cirrhosis. Results Out of 122 cirrhotic patients, 82 patients (63% male) with median Child score of 6 (range 5–12) and median MELD score of 10 (range 6–32) were included. Increasing Child score, INR and decreasing albumin were correlated with TO. In addition, decompensated patients with ascites showed more abnormal TO and TS. During the observation period, patients with more abnormal TO showed significantly higher rate of rising MELD Score at 6 months (p = 0.03). Nevertheless, at least in our collective HRT-parameters were not independent predictors of deterioration of cirrhosis. Conclusion Parameters of HRT are closely associated with deterioration of cirrhosis and might be helpful in its prediction.
Journal of Hepatology | 2016
Christian Jansen; Christopher Bogs; Wim Verlinden; Maja Thiele; P. Moeller; J. Goertzen; Jennifer Lehmann; Michael Praktiknjo; Johannes Chang; Aleksander Krag; Christian P. Strassburg; S. Franque; Jonel Trebicka