21. Chirurgischen Forschungstage


The 21. Chirurgischen Forschungstage took place in Cologne. Five of our students gave terrific presentations:
S. Moosburner gave an oral presentation on „Steatotic Liver Transplantation – a Growing Problem with Severe Complications“, H. Everwien on „Different biological scffolds as a platform for engineering an endocrine Neo-Pancreas by using decellularization and recellularization techniques“, M. Noesser on „A comprehensive description of the development of a stable closed circuit for ex vivo rat liver machine perfusion“, R. Horner on „Is Percoll purifcation necessary for isolation of primary human hepatocytes?“, and N. Seiffert on „Recellularization of Decellularized Bovine Carotid Arteries using Human Endothelial Progenitor Cells: One Step towards an Autologous Bypass Graft“.

ECRT Kickbox – Junior Scientist Grant

Karl Hillebrandt receives one of the 2017 Einstein Center for Regenerative Therapies (ECRT) Kickbox – Junior Scientist Grant. The project is entitled "Fighting liver cirrhosis? Establishment and analysis of decellularized human cirrhotic liver slices as a 3-dimensional model to study cell matrix interactions".

Liver cirrhosis is one of the main indications for liver transplantation. Due to the organ shortage, this therapy option is limited to the minority of patients suffering from cirrhosis. Therefore, there is a need of alternative treatment options.The aim of our project is to establish a decellularization protocol for human cirrhotic livers slices, which preserves the natural extracellular matrix (ECM) of cirrhotic livers. These decellularized liver slices will serve as a 3 dimensional model to study cell matrix interactions. If we are able to establish a protocol which will preserve the ECM, we will conduct in vitro recellularization experiments to study how the cirrhotic ECM will change the genotype and phenotype of different cell types. With this knowledge we aim to modify specific cell types in vivo or vitro for example prior to cell transplantation. Our ambition is to steer the cell matrix interaction via these modified cells after their transplantation and thereby halt or even reverse the progress of liver cirrhosis. This approach may offer an alternative treatment option in the future.
Team : Karl Hillebrandt, Oliver Klein, Ben Strücker, Igor Sauer


BIH Paper of the Month...

Benjamin Strücker, Hendrik Napierala and the rest of the team were awarded with the BIH Paper of the Month for their publication on a new method for developing a transplantable endocrine Neo-Pancreas.
The BIH Paper of the Month is awarded by the BIH Board of Directors to honor a special publication achievement from the joint research space of Charité and MDC. The Paper of the Month is sponsored by the Stiftung Charité as part of its Johanna Quandt Private Excellence Initiative.

H. Napierala, K.-H. Hillebrandt, N. Haep, P. Tang, M. Tintemann, J. Gassner, M. Noesser, H. Everwien, N. Seiffert, M. Kluge, E. Teegen, D. Polenz, S. Lippert, D. Geisel, A. Reutzel Selke, N. Raschzok, A. Andreou, J. Pratschke, I. M. Sauer & B. Struecker. Engineering an endocrine Neo-Pancreas by repopulation of a decellularized rat pancreas with islets of Langerhans. Scientific Reports 7. Article number: 41777 (2017) doi:10.1038/srep41777

You may download the publication here.

Engineering an endocrine Neo-Pancreas

scientific reports
Scientific Reports accepted our latest paper on „Engineering an endocrine Neo-Pancreas by repopulation of a decellularized rat pancreas with islets of Langerhans“. Authors are H. Napierala, K. Hillebrandt, N. Haep, P. Tang, M. Tintemann, J. Gassner, M. Noesser, H. Everwien, N. Seiffert, M. Kluge, E. Teegen, D. Polenz, S. Lippert, D. Geisel, A. Reutzel-Selke, N. Raschzok, A. Andreou, J. Pratschke, I.M. Sauer, and B. Struecker.

Decellularization of pancreata and repopulation of these non-immunogenic matrices with islets and endothelial cells could provide transplantable, endocrine Neo- Pancreata. In this study, rat pancreata were perfusion decellularized and repopulated with intact islets, comparing three perfusion routes (Artery, Portal Vein, Pancreatic Duct). Decellularization effectively removed all cellular components but conserved the pancreas specific extracellular matrix. Digital subtraction angiography of the matrices showed a conserved integrity of the decellularized vascular system but a contrast emersion into the parenchyma via the decellularized pancreatic duct. Islets infused via the pancreatic duct leaked from the ductular system into the peri-ductular decellularized space despite their magnitude. TUNEL staining and Glucose stimulated insulin secretion revealed that islets were viable and functional after the process.
We present the first available protocol for perfusion decellularization of rat pancreata via three different perfusion routes. Furthermore, we provide first proof-of-concept for the repopulation of the decellularized rat pancreata with functional islets of Langerhans. The presented technique can serve as a bioengineering platform to generate implantable and functional endocrine Neo-Pancreata.

Recellularization of rat livers: morphology and function

The Journal of Tissue Engineering and Regenerative Medicine accepted our paper Evolution of graft morphology and function after recellularization of decellularized rat liversfor publication.

Decellularization of livers is a well-established procedure. Data on different reseeding techniques or the functional evolution and re-organization processes of repopulated grafts remains limited.
We established a proprietary, customized bioreactor to repopulate decellularized rat livers (n=21) with primary rat hepatocytes (150 x 106 cells) via the hepatic artery and to subsequently evaluate graft morphology and function during seven days of ex vivo perfusion. Grafts were analyzed at 1h, 6h, 12h, 24h, 3d, 5d and 7d after recellularization (all n=3) by immunohistologic evaluation, hepatocyte-related enzyme (AST, ALT, LDH) and albumin measurement in the perfusate.
To the best of our knowledge, this is the first available protocol for repopulation of rat livers via the hepatic artery. Within the first 24 hours after repopulation, the hepatocytes seemed to migrate out of the vascular network and form clusters in the parenchymal space around the vessels. Graft function increased for the first 24 hours after repopulation with a significantly higher function compared to standard 2D culture after 24 hours. Thereafter, graft function constantly decreased with significantly lower values after six and seven days of perfusion, although histologically viable hepatocytes were found even after this period. Our data suggests that due to a constant loss of function, repopulated grafts should potentially be implanted as soon as cell engraftment and graft re-organization are completed.

Authors are Antje Butter, Khalid Aliyev, Karl-Herbert Hillebrandt, Nathanael Raschzok, Martin Kluge, Nicolai Seiffert, Peter Tang, Hendrik Napierala, Muhammad Imtiaz Ashraf, Anja Reutzel-Selke, Andreas Andreou, Johann Pratschke, Igor Maximilian Sauer, and Benjamin Struecker.


Although we do hate Facebook, feel kind of robbed and dislike the music –
We have to admit: 7,201,027 clicks (as of January 25th, 2016) are impressive…

Feature in Berliner Zeitung on Tissue Engineering

Recellularized liver created in our lab featured in Berliner Zeitung.

ESOT | YPT – Interview with Karl Hillebrandt

Being the winner of the Rising Stars Video Session organised by the YPT Committee at the ESOT2015 Brussels Congress Karl Hillebrandt gave an interview for the ESOT | YPT webpage.
His abstract "Optimized decellularization of rat livers byarterial and portal venous perfusion underoscillating pressure conditions" and the accompanying video were the most voted at the Rising Stars Session, where the audience voted live for the best video abstract. You can read Karl's abstract in the special ESOT2015 issue of Transplant International.

Implantation of a Neo Bile Duct in domestic pigs

European Surgical Research accepted our latest paper entitled "Implantation of a tissue engineered Neo Bile Duct in domestic pigs" for publication. Authors are B. Struecker, K. Hillebrandt, N. Raschzok, K. Jöhrens, A. Butter, P. Tang, A. Andreou, H. Napierala, D. Polenz, A. Reutzel-Selke, T. Denecke, J. Pratschke, and I.M Sauer.

Extrahepatic bile duct injuries remain severe complications during cholecystectomy and often require reconstruction by bilioenteric anastomosis (i.e. hepatico-jejunostomy), which comes along with further long-term complications (e.g. recurring ascending cholangitis, secondary biliary cirrhosis). Furthermore, in case of inherent extrahepatic biliary atresia or during liver transplant artificial or engineered bile ducts could enable novel surgical strategies without the need for hepatico-jejunostomy. We present data on the implantation of in vitro generated Neo Bile Ducts in five domestic pigs. Neo Bile Ducts were engineered through decellularization of allogeneic blood vessels and recellularization with autologous cholangiocytes.On postoperative days 0, 1, 7 and 14 blood samples were taken and analyzed (AST, ALT, Bilirubin, Alkaline Phosphatase, Creatinine and Leukocytes). An magnetic resonance cholangiography was performed on postoperative day 14 with one pig. 14 days after implantation pigs were sacrificed and bile ducts were explanted. All pigs survived the complete study period without severe complications. None of the pigs showed signs of biliary leakage or peritonitis. Neo Bile Ducts were infiltrated by neutrophils and neo-angiogenesis was observed around and into the implanted tissue. Whether the presented technique enables the long-term replacement of native bile ducts has to be further evaluated.

Karl Hillebrandt – YPT Rising Star


Karl Hillebrandt won this year's YPT Rising Stars Video Session Award. He presented the studies on „Optimized decellularization of rat livers by arterial and portal venous perfusion under oscillating pressure conditions“ during the 17th congress of the European Society for Organ Transplantation (ESOT) 2015 in Brüssel. Young Professionals in Transplantation (YPT) is a forum for junior professionals throughout Europe working in the field of transplantation.

microRNAs in liver tissue engineering

Our paper "microRNAs in liver tissue engineering - New promises for failing organs" was accepted for publication in Advanced Drug Delivery Reviews (IF: 15.038). Authors are Nathanael Raschzok, Hannes Sallmon, Johann Pratschke and Igor M. Sauer.

miRNA-based technologies provide attractive tools for several liver tissue engineering approaches. Herein, we review the current state of miRNA applications in liver tissue engineering. Several miRNAs have been implicated in hepatic disease and proper hepatocyte function. However, the clinical translation of these findings into tissue engineering has just begun. miRNAs have been successfully used to induce proliferation of mature hepatocytes and improve the differentiation of hepatic precursor cells. Nonetheless, miRNA-based approaches beyond cell generation have not yet entered preclinical or clinical investigations. Moreover, miRNA-based concepts for the biliary tree have yet to be developed. Further research on miRNA based modifications, however, holds the promise of enabling significant improvements to liver tissue engineering approaches due to their ability to regulate and fine-tune all biological processes relevant to hepatic tissue engineering, such as proliferation, differentiation, growth, and cell function.

Cover – march issue of Tissue Engineering

One of the figures of our paper „Porcine liver decellularization under oscillating pressure conditions – A technical refinement to improve the homogeneity of the decellularization process“ made it to the cover of the march issue of Tissue Engineering, Part C : Methods.

Congratulations to Dietrich Polenz, who made the corrosion cast of a decellularized pig liver matrix: red, hepatic artery; blue, portal vein; yellow, bile duct and gallbladder.

Ben Strücker: Charité Clinical Scientist

Dr. med Benjamin Strücker successfully applied for the Charité Clinical Scientist 2015 program.

His project is entitled „Humanized Porcine Liver““. Clinical mentor is Prof. Dr. Johann Pratschke, scientific mentors is Priv.-Doz. Dr. med Igor M. Sauer.

The program is supported by Stiftung Charité which was endowed by the entrepreneur Johanna Quandt in order to promote biomedical "knowledge entrepreneurs" that is, change makers in biomedicine at the Charité. The goal of this program is to develop new career paths in clinical specialist medical training. The focus of the training program "Clinical Scientist" is translational research ("bench-to-bedside") which will be realized by a reduction in clinical routine and an improved curriculum with defined goals.

Decellularization of rat liver – New time lapse video