Presentations at DTG 2014
Ben Strücker: Charité Clinical Scientist
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.
Sham Laparotomy and microRNA Expression in Rats
Studies on liver regeneration following partial hepatectomy (PH) have identified several microRNAs (miRNAs) that show a regulated expression pattern. These studies involve major surgery to access the liver, which is known to have intrinsic effects on hepatic gene expression and may also affect miRNA screening results. We performed two-third PH or sham laparotomy (SL) in Wistar rats to investigate the effect of both procedures on miRNA expression in liver tissue and corresponding plasma samples by microarray and qRT-PCR analyses. As control groups, non-treated rats and rats undergoing anesthesia only were used. We found that 49 out of 323 miRNAs (15%) were significantly deregulated after PH in liver tissue 12 to 48 hours postoperatively (>20% change), while 45 miRNAs (14%) were deregulated following SL. Out of these miRNAs, 10 miRNAs were similarly deregulated after PH and SL, while one miRNA showed opposite regulation. In plasma, miRNA upregulation was observed for miR-133a and miR-133b following PH and SL, whereas miR-100 and miR-466c were similarly down-regulated following anesthesia and surgery. We show that miRNAs are indeed regulated by sham laparotomy and anesthesia in rats. These findings illustrate the critical need for finding appropriate control groups in experimental surgery.
Authors are W. Werner, H. Sallmon, A. Leder, S. Lippert, A. Reutzel-Selke, M.H. Morgül, S. Jonas, S. Dame, P. Neuhaus, J. Iacomini, S.G. Tullius, I.M. Sauer and N. Raschzok.
Textbook of Organ Transplantation Set
Beautifully produced in full color throughout, and with over 600 high-quality illustrations, it successfully
- Provides a solid overview of what transplant clinicians/surgeons do, and with topics presented in an order that a clinician will encounter them.
- Presents a holistic look at transplantation, foregrounding the interrelationships between transplant team members and non-surgical clinicians in the subspecialties relevant to pre- and post-operative patient care, such as gastroenterology, nephrology, and cardiology.
- Offers a focused look at pediatric transplantation, and identifies the ways in which it significantly differs from transplantation in adults.
- Includes coverage of essential non-clinical topics such as transplant program management and administration; research design and data collection; transplant policy and bioethical issues.
Editors are Allan D. Kirk, Stuart J. Knechtle, Christian P. Larsen, Joren C. Madsen, Thomas C. Pearson, and Steven A. Webber.
I.M. Sauer, N. Raschzok und P. Neuhaus contributed chapter 47: „Artificial Liver, In Vivo Tissue Engineering, and Organ Printing – Solutions for Organ Scarcity“
The Wiley-Blackwell book (ISBN: 978-1-118-87014-3, 1880 pages) is available here.
Decellularization of porcine livers
Co-authors are K. Hillebrandt, R. Voitl, A. Butter, R.B. Schmuck, A. Reutzel-Selke, D. Geisel, K. Joehrens, P.A. Pickerodt, N. Raschzok, G. Puhl, P. Neuhaus, J. Pratschke, and I.M. Sauer.
Decellularization and recellularization of parenchymal organs may facilitate the generation of autologous functional liver organoids by repopulation of decellularized porcine liver matrices with induced liver cells. We present an accelerated (7 h overall perfusion time) and effective protocol for human scale liver decellularization by pressure-controlled perfusion with 1% Triton X-100 and 1% SDS via the hepatic artery (120 mmHg) and portal vein (60 mmHg). In addition, we analyzed the effect of oscillating pressure conditions on pig liver decellularization (n=12). The proprietary perfusion device used to generate these pressure conditions mimics intra-abdominal conditions during respiration to optimize microperfusion within livers and thus optimize the homogeneity of the decellularization process. The efficiency of perfusion decellularization was analyzed by macroscopic observation, histological staining (H&E, Sirius red, Alcian blue), immunohistochemical staining (collagen IV, laminin, fibronectin) and biochemical assessment (DNA, collagen, glycosaminoglycans) of decellularized liver matrices. The integrity of the extracellular matrix post-decellularization was visualized by corrosion casting and three-dimensional CT scanning. We found that livers perfused under oscillating pressure conditions (P+) showed a more homogenous course of decellularization and contained less DNA compared to livers perfused without oscillating pressure conditions (P-). Microscopically, livers from the (P-) group showed remnant cell clusters, while no cells were found in livers from the (P+) group. The grade of disruption of the ECM was higher in livers from the (P-) group, although the perfusion rates and pressure did not significantly differ. Immunohistochemical staining revealed that important matrix components were still present after decellularization. Corrosion casting showed an intact vascular (portal vein and hepatic artery) and biliary framework. In summary, the presented protocol for pig liver decellularization is quick (7 h) and effective. The application of oscillating pressure conditions improves the homogeneity of perfusion and thus the outcome of the decellularization process.
Decellularization and oscillating pressure conditions
One approach of regenerative medicine to generate functional hepatic tissue in vitro is de- and recellularization and several protocols for the decellularization of different species have been published. To the best of our knowledge this is the first report on rat liver decellularization by perfusion via the hepatic artery under oscillating pressure conditions, intending to optimize microperfusion and minimize damage to the ECM. Four decellularization protocols were compared: perfusion via the portal vein (PV) or the hepatic artery (HA), with (+P) or without (-P) oscillating pressure conditions. All rat livers (n=24) were perfused with 1% Triton X-100 and 1% SDS, each for 90 minutes with a perfusion rate of 5ml/min. Perfusion decellularization was observed macroscopically and the decellularized liver matrices (DLMs) were analyzed by histology and biochemical analyses (e.g., levels of DNA, glycosaminoglycans (GAG), and hepatocyte growth factor (HGF). Livers decellularized via the hepatic artery and under oscillating pressure showed a more homogenous decellularization and less remaining DNA, compared to livers of the other experimental groups. The novel decellularization method described is effective, quick (3 hours) and gentle to the ECM and thus represents an improvement of existing methodology.
Nature Reviews Gastroenterology and Hepatology
The treatment of end-stage liver disease and acute liver failure remains a clinically relevant issue. Although orthotopic liver transplantation is a well-established procedure, whole-organ transplantation is invasive and increasingly limited by the unavailability of suitable donor organs. Artificial and bioartificial liver support systems have been developed to provide an alternative to whole organ transplantation, but despite three decades of scientific efforts, the results are still not convincing with respect to clinical outcome. In this Review, conceptual limitations of clinically available liver support therapy systems are discussed. Furthermore, alternative concepts, such as hepatocyte transplantation, and cutting-edge developments in the field of liver support strategies, including the repopulation of decellularized organs and the biofabrication of entirely new organs by printing techniques or induced organogenesis are analysed with respect to clinical relevance. Whereas hepatocyte transplantation shows promising clinical results, at least for the temporary treatment of inborn metabolic diseases, so far data regarding implantation of engineered hepatic tissue have only emerged from preclinical experiments. However, the evolving techniques presented here raise hope for bioengineered liver support therapies in the future.
Update: The review „Liver support strategies: cutting-edge technologies“ (authors: Benjamin Struecker, Nathanael Raschzok & Igor M. Sauer) is now available.
IEEE Engineering in Medicine and Biology Society
The conference will cover diverse topics such as biomedical engineering, healthcare technologies, and medical and clinical applications.
The ESAO will be represented via a minisymposium entitled "Artificial Organs for Metabolic Support. The most Challenging Problems". Jan Wojcicki will give a presentation on "Artificial Organs for Metabolic Support: The Most Challenging Problems of Artificial Pancreas", Bernd Stegmayr on "Artificial Organs for Metabolic Support: The Most Challenging Problems in Severe Kidney Injury When Dialysis Is Necessary" and Igor Sauer on "Artificial Organs for Metabolic Support: The Most Challenging Problems of Liver Support".
Noninvasive monitoring of liver cell transplantation
Liver cell transplantation was developed as a therapeutic alternative to solid liver transplantation in the management of liver-based metabolic disorders and may be useful for the treatment of acute or chronic liver failure. While clinical studies have demonstrated temporal amelioration of the symptoms of metabolic liver disorders by transplanted liver cells, the long-term outcome of liver cell transplantation is still insufficient. A major limitation for improving liver cell transplantation is the inability to track the fate of cells once they have been infused. Radionuclide-based imaging, MRI and optical methods have been investigated as methods for noninvasive monitoring of liver cell transplantation. This article summarizes and critically discusses these approaches, with a special focus on MRI-based tracking of transplanted liver cells and provides an outlook on possible clinical applications for the near future.
Einladunfgzur öffentlichen Abschlusspräsentation
Dear ladies and gentlemen,
Sie sind herzlich eingeladen, unserer öffentlichen Abschlusspräsentation unseres EU/EFRE-Projekts am 20.03.2013 um 15:00 Uhr beizuwohnen. Zusammen mit unseren Partnern der Firma microparticles GmbH werden wir den aktuellen Stand zur „Entwicklung von Partikel zur Detektion und ultralokoregionären Stimulation transplantierter Leberzellen“ darlegen.
You are cordially invited to attend our public presentation of our EU/EFRE project. Together with our partners of microparticles GmbH we will present our latest results concerning the „Development of particles for detection and ultralocoregional stimulation of transplanted liver cells“.
Wann/When?
20.03.2013 um/at 15:00
Wo/Where?
Experimentelle Chirurgie und Regenerative Medizin
Klinik für Allgemein-, Viszeral- und Transplantationschirurgie
Charité, Campus Virchow-Klinikum
Forschungshaus/BMFZ
Pilzraum, 1.OG
Wir wären dankbar, wenn Sie Ihr Kommen via email (anja.selke@charite.de)bestätigen könnten.
RSVP via email (anja.selke@charite.de).
David Mücke successfully defended thesis
Congratulations !
XXXX ESAO Congress in Glasgow
Presentations at EASO 2012 in Rostock, Germany
“Liver: Current regenerative strategies and future solutions for the liver" (N. Raschzok, oral presentation)
"Neohybrid liver graft - a novel concept of in vivo tissue-engineering" (S. Rohn, oral presentation)
"Micro RNAs in liver regeneration: the mysterious MIR-352" (L. Lisboa, oral presentation)
"Micron-sized iron oxide particles for detection and loco-regional stimulation of transplanted liver cells" (A. Leder, oral presentation)
"Prospective validation of cross organ serum protein biomarkers – Initial results with CXCL9 and CD44 for diagnosis of acute liver rejection" (K.A. Prabowo, poster presentation)
MRI and ectopic liver cell transplantation - new paper
Liver cell transplantation is a promising approach for the treatment of metabolic liver disorders. However, a method for noninvasive monitoring during liver cell transplantation is not available clinically. The aim of this study was to investigate the feasibility of fast dynamic MRI monitoring during liver cell infusion to the spleen, which is considered an ectopic implantation site for liver cell transplantation. Porcine liver cells were labeled with micron-sized iron oxide particles and infused to the spleens of pigs (n = 5) via the lineal artery. MRI was performed using a 3-T MR scanner. Initially, T1- and T2-weighted pulse sequences were tested. Thereafter, fast dynamic MRI was performed during cell infusion. MR findings were verified by immunohistological examinations.
Images from static MRI (TR/TE, 2500/105.2) showed significantly lower signal intensity and signal-to-noise ratio after cell infusion compared with pretransplant images. T2-weighted fast dynamic MRI enabled visualization of signal decrease of the spleen during cell infusion. When cells were infused systemically, no signal changes in the spleen were observed. This study shows that fast dynamic MRI can enable noninvasive monitoring during liver cell transplantation to the spleen. This approach could be useful for preclinical studies and for quality control of clinical liver cell transplantation.
