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Dive into the research topics where Michael Praktiknjo is active.

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Featured researches published by Michael Praktiknjo.


Liver International | 2017

Shear-wave elastography of the liver and spleen identifies clinically significant portal hypertension: A prospective multicentre study.

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.


American Journal of Transplantation | 2010

Perioperative Infliximab Application Ameliorates Acute Rejection Associated Inflammation After Intestinal Transplantation

Thomas Pech; Tobias Finger; J. Fujishiro; Michael Praktiknjo; Ichiro Ohsawa; Kareem Abu-Elmagd; A. Limmer; A. Hirner; Jörg C. Kalff; Nico Schaefer

As we have shown in the past, acute rejection‐related TNF‐α upregulation in resident macrophages in the tunica muscularis after small bowel transplantation (SBTx) results in local amplification of inflammation, decisively contributing to graft dysmotility. Therefore, the aim of this study is to investigate the effectiveness of the chimeric‐monoclonal‐anti‐TNF‐α antibody infliximab as perioperative single shot treatment addressing inflammatory processes during acute rejection early after transplantation. Orthotopic, isogenic and allogenic SBTx was performed in rats (BN‐Lewis/BN‐BN) with infliximab treatment. Vehicle and IV‐immunoglobulin‐treated animals served as controls. Animals were sacrificed after 24 and 168 h. Leukocyte infiltration was investigated in muscularis whole mounts by immunohistochemistry, mediator mRNA expression by Real‐Time‐RT‐PCR, apoptosis by TUNEL and smooth muscle contractility in a standard organ bath. Both, infliximab and Sandoglobulin® revealed antiinflammatory effects. Infliximab resulted in significantly less leukocyte infiltration compared to allogenic controls and IV‐immunoglobulin, which was accompanied by lower gene expression of MCP‐1 (24 h), IFN‐γ (168 h) and infiltration of CD8‐positive cells. Smooth muscle contractility improved significantly after 24 h compared to all controls in infliximab treated animals accompanied by lower iNOS expression. Perioperative treatment with infliximab is a possible pharmaceutical approach to overcome graft dysmotility early after SBTx.


Gut | 2016

Algorithm to rule out clinically significant portal hypertension combining Shear-wave elastography of liver and spleen: a prospective multicentre study

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 …


American Journal of Transplantation | 2012

Intestinal Regeneration, Residual Function and Immunological Priming Following Rescue Therapy After Rat Small Bowel Transplantation

Thomas Pech; M. von Websky; Ichiro Ohsawa; K. Kitamura; Michael Praktiknjo; Azin Jafari; Tim O. Vilz; Sven Wehner; Kareem Abu-Elmagd; Jörg C. Kalff; Nico Schaefer

Clinical evidence suggests that recurrent acute cellular rejection (ACR) may trigger chronic rejection and impair outcome after intestinal transplantation. To test this hypothesis and clarify underlying molecular mechanisms, orthotopic/allogenic intestinal transplantation was performed in rats. ACR was allowed to occur in a MHC‐disparate combination (BN‐LEW) and two rescue strategies (FK506monotherapy vs. FK506+infliximab) were tested against continuous immunosuppression without ACR, with observation for 7/14 and 21 days after transplantation. Both, FK506 and FK506+infliximab rescue therapy reversed ACR and resulted in improved histology and less cellular infiltration. Proinflammatory cytokines and chemotactic mediators in the muscle layer were significantly reduced in FK506 treated groups. Increased levels of CD4, FOXP3 and IL‐17 (mRNA) were observed with infliximab. Contractile function improved significantly after FK506 rescue therapy, with a slight benefit from additional infliximab, but did not reach nontransplanted controls. Fibrosis onset was detected in both rescue groups by Sirius‐Red staining with concomitant increase of the fibrogenic mediator VEGF. Recovery from ACR could be attained by both rescue therapy regimens, progressing steadily after initiation of immunosuppression. Reversal of ACR, however, resulted in early stage graft fibrosis. Additional infliximab treatment may enhance physiological recovery of the muscle layer and enteric nervous system independent of inflammatory reactions.


Hepatology | 2018

Increase in liver stiffness after transjugular intrahepatic portosystemic shunt is associated with inflammation and predicts mortality

Christian Jansen; Philipp T. Möller; Carsten H. Meyer; Carl Christian Kolbe; Christopher Bogs; Alessandra Pohlmann; Robert Schierwagen; Michael Praktiknjo; Zeinab Abdullah; Jennifer Lehmann; Daniel Thomas; Christian P. Strassburg; Eicke Latz; Sebastian Mueller; Martin Rössle; Jonel Trebicka

Transjugular intrahepatic portosystemic shunt (TIPS) efficiently treats complications of portal hypertension. Liver and spleen stiffness might predict clinically significant portal hypertension. This prospective study investigated liver stiffness in patients receiving TIPS regardless of indication. Of 83 included patients, 16 underwent transient elastography immediately before and 30 minutes after TIPS (acute group), while 67 received shear wave elastography of liver and spleen 1 day before and 7 days after TIPS (chronic group) and were followed further. In blood samples obtained before TIPS from cubital, portal, and hepatic veins, levels of several interleukins (IL1b, IL6, IL8, IL10, IL18) and interferon‐gamma were analyzed. In 27 patients (5 acute, 22 chronic), it resulted in an increase in liver stiffness of >10%. In 56 patients, liver stiffness decreased or remained unchanged (<10%). Importantly, spleen stiffness measured by shear wave elastography decreased in all patients (chronic group). None of the clinical or laboratory parameters differed between patients with increase in liver stiffness and those without. Of note, patients with increased liver stiffness showed higher overall and/or hepatic venous levels of proinflammatory cytokines at TIPS and higher incidence of organ failure and worse survival after TIPS. C‐reactive protein values and increase of >10% in liver stiffness after TIPS were the only independent predictors of mortality in these patients. Conclusion: This study demonstrates that the presence of systemic inflammation predisposes patients to develop increased liver stiffness after TIPS, a predictor of organ failure and death. (NCT03072615) (Hepatology 2018;67:1472‐1484).


Transplantation | 2012

Combination therapy of tacrolimus and infliximab reduces inflammatory response and dysmotility in experimental small bowel transplantation in rats.

Thomas Pech; Jun Fujishiro; Tobias Finger; Ichiro Ohsawa; Michael Praktiknjo; Kareem Abu-Elmagd; Martin von Websky; Marcus Overhaus; Joerg C. Kalff; Nico Schaefer

Background. Intestinal transplantation initiates a functionally relevant inflammatory response by activation of resident macrophages within the muscularis associated with dysmotility. Infliximab is used successfully as a potent anti-inflammatory agent for the treatment of chronic inflammatory bowel diseases and as rescue therapy in acute steroid-resistant rejection in selected settings in clinical small bowel transplantation. We hypothesize that additional perioperative treatment with infliximab diminishes initiation of the inflammatory cascade and improves motility in small bowel grafts using a standard tacrolimus immunosuppressive protocol. Methods. Orthotopic intestinal transplantation was performed in rats. In two treatment groups (24/168 hr), infliximab was administered intravenously directly after reperfusion and tacrolimus was injected intramuscularly after transplantation and once a day. Two other treatment groups (24/168 hr) received standard immunosuppressive therapy with tacrolimus. Isogenic and allogenic transplanted vehicle-treated animals (24/168 hr) and native gut served as control. Results. Infliximab-treated grafts exhibited significantly less leukocyte infiltration at 24/168 hr after transplantation and at 168 hr significantly less apoptosis in the tunica muscularis compared with tacrolimus monotherapy. Additional infliximab treatment resulted in increased smooth muscle contractility (30%) after 24 hr compared with tacrolimus control. Conclusions. Dysmotility of transplanted small bowel results from reperfusion injury and acute rejection. Additional perioperative treatment with infliximab reduces early unspecific inflammatory responses and complements immunosuppressive therapy with tacrolimus.


Hepatology | 2018

Fat-free muscle mass in magnetic resonance imaging predicts acute-on-chronic liver failure and survival in decompensated cirrhosis

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)


Gastroenterology Report | 2017

Portal vein thrombosis in patients with cirrhosis

Leona von Köckritz; Andrea De Gottardi; Jonel Trebicka; Michael Praktiknjo

Abstract Portal vein thrombosis (PVT) is frequent in patients with liver cirrhosis and possible severe complications such as mesenteric ischemia are rare, but can be life-threatening. However, different aspects of clinical relevance, diagnosis and management of PVT are still areas of uncertainty and investigation in international guidelines. In this article, we elaborate on PVT classification, geographical differences in clinical presentation and standards of diagnosis, and briefly on the current pathophysiological understanding and risk factors. This review considers and highlights the pitfalls of the various treatment approaches and prophylactic treatments. Finally, we review the controversial issue of clinical impact of PVT on prognosis, especially considering liver transplantation and future perspectives.


Pathobiology | 2013

A natural tetrahydropyrimidine, ectoine, ameliorates ischemia reperfusion injury after intestinal transplantation in rats.

Thomas Pech; Ichiro Ohsawa; Michael Praktiknjo; Marcus Overhaus; Sven Wehner; Martin von Websky; Kareem Abu-Elmagd; Gerhild van Echten-Deckert; Joerg C. Kalff; Nico Schaefer

Background/Aims: Ischemia reperfusion (I/R) injury after small bowel transplantation leads to inflammatory reactions and loss of structural integrity with subsequent graft contractile dysfunction in the early postoperative phase. The natural tetrahydropyrimidine ectoine (1-,4-,5-,6-tetrahydro-2-methyl-4-pyrimidine carboxylic acid; THP) protects the ileal mucosa and muscularis against effects of I/R injury in an experimental model of isolated graft reperfusion. The effects of THP treatment were evaluated in an established experimental intestinal transplant model. Methods: Isogenic, orthotopic small bowel transplantation was performed in Lewis rats (6 h cold ischemia time). Perioperative THP treatment (intraluminal/intravascular) groups were compared to vehicle-treated animals (after 3 and 24 h) and non-transplanted controls (n = 5/group). Park’s score defined the effects of I/R injury. The infiltration of neutrophils, monocytes and macrophages, mRNA expression of IL-6 and TNF-α, serum levels of IL-6 and NO and smooth muscle contractility were evaluated. Results: Improved graft outcome after intraluminal and intravascular THP treatment was defined by considerably ameliorated neutrophil infiltration and less histological signs of I/R injury (p ≤ 0.05). In the presence of THP, mRNA expression of IL-6 and TNF-α and IL-6 and NO serum levels were reduced and smooth muscle function was improved. Conclusion: THP treatment offers protection against the effects of I/R injury in intestinal transplantation in vivo, however, only as supplementary treatment option.


Liver Transplantation | 2018

Increased myocardial contractility identifies patients with decompensated cirrhosis requiring liver transplantation

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.

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