ASAIO 2008

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Florian Vondran's paper "Isolation of primary human hepatocytes after partial hepatectomy: criteria for identification of the most promising liver specimen." has been published in the March issue of Artificial Organs (Artif Organs 2008, 32: 205-213). Demands for primary human hepatocytes are continuously increasing, while supply is insufficient due to limited cell sources. To improve cell availability, the present study investigates the influence of donor liver characteristics on the outcome of hepatocyte isolation from surgically removed liver tissue (n = 50). Hepatocytes were isolated from liver specimens using a standardized two-step collagenase perfusion technique. The patient's sex, previous chemotherapy, or histopathology have shown no influence. Donor age significantly affected the isolation outcome, but was not found suitable for predicting cell yields. Preoperative blood parameters did not correlate with cell yield, although cell function was affected: total protein, albumin synthesis, and cell viability were significantly decreased for serum gamma-glutamyl-transferase (GGT) levels >60 U/L. Specimens from patients with benign diseases gave significantly higher cell yields than tissue removed due to secondary and primary tumors, respectively. The indication for surgery is a valuable basis for identifying the most yielding specimens. Hepatocytes from donors with high GGT levels appear to show reduced functional properties.

Paul P.C. Poyck (AMC) defended his thesis

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ESAO Board of Governors - I.M. Sauer elected

Paul P.C. Poyck from the Department of Surgery (Experimental Surgery) of the Academic Medical Center (AMC), University of Amsterdam, The Netherlands, successfully defended his thesis entitled "Towards application of a human liver cell line for use in the AMC bioartificial liver".
The Berlin group congratulates him and Prof. Chamuleau for his great work! 

ESAO 2007 - Presentations

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During the annual meeting of the ESAO 2007 in Krems Dr. Igor M. Sauer has been elected for the Board of Governors of the European Society for Artificial Organs (ESAO).

ESAO 2007 - One Day on the Liver

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Nathanael Raschzok, Haluk Morgül, and Florian Vondran presented their latest results at the XXXIV Congress of ESAO 2007 in Krems, Austria:
  • N. Raschzok, M.H. Morgul, F.W.R. Vondran, R. Schwartlander, I.M. Sauer: The SlideObserver – A new concept for the parallel operation of two SlideReactor bioreactor systems
  • M.H. Morgul, N. Raschzok, R. Schwartlander, F.W.R. Vondran, G. Pless, J. Pinkernelle, U. Teichgraber, I.M. Sauer: Transplantation of primary human hepatocytes – iron oxide labelling for cell detection via MRI
  • F.W.R. Vondran, E. Katenz, R. Schwartlander, M.H. Morgul, N. Raschzok, X. Gong, X. Cheng, P. Neuhaus, I.M. Sauer: Impact of donor liver characteristics on the cell function of primary human hepatocytes

Article among top 10 most cited in AO

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Retreat 2007

The Editor-in-Chief Paul S. Malchesky informed us that the article  "Modular Extracorporeal Liver Support"  is  among top 10 most cited in Artificial Organs for the year 2006.
The article
"`Blogs` and `Wikis Are Valuable Software Tools for Communication Within Research Groups" was number three of the five most-accessed articles in different areas of artificial organs research from 2006.

MELS CellModule vs. AMC-BAL

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The Retreat 2007 of the group took place in Binz, a small seaside village on the German island Ruegen. Venue was the coast guard station designed an built by the architect Ulrich Müther. It was built in 1968 and serves as a great example of the hyperbal concrete structures that he used in most of his works (for more information [in German] see article in brand eins 9/2003: "Nach der Utopie" .

Charité Biomedical Entrepreneurship Summit

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Paul Poyck published the results of our in vitro comparison of the two bioartificial liver support systems: MELS CellModule and AMC-BAL (Int J Artif Organs. 2007; 30(3):183-191): Clinically applied bioartificial liver (BAL) support systems are difficult to compare with regard to overall hepatocyte-specific function and clinical outcome. We compared two clinically applied BAL systems, the Modular Extracorporeal Liver Support (MELS) CellModule and the AMC-bioartificial liver (AMC-BAL) in an in vitro set-up. Both BAL systems were loaded with 10 billion freshly isolated porcine hepatocytes, cultured for 7 days and tested on days 1, 2, 4 and 7. Average decrease in hepatocyte-specific functions over 7 days was 9.7%. Three parameters differed between both bioreactors: lidocaine elimination at days 1 and 2 was significantly higher in the AMCBAL, ammonia elimination showed a significantly higher trend for the AMC-BAL over 7 days and LDH release was significantly lower at day 7 for the MELS CellModule. In conclusion, this first in vitro comparison of two clinically applied BAL systems shows comparable functional capacity over a period of 7 days.

Perspectives in Liver Transplantation

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The International Medical Students Research Congress (IMSRC) gives students the opportunity to present the results of their scientific research projects. IMSRC 2007 will be held between 11-13 of May, 2007 at Istanbul University, Cerrahpaşa Medical Faculty. Haluk Morgül, Nathanael Raschzok, Keshraw Karmand and Dominik Modest will present their latest results.

International Medical Students Research Congress

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Greetings from Chongqing, PR China

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Nils Billeckes paper „An operational concept for long-term cinemicrography of cells in mono- and co-culture under highly controlled conditions - the SlideObserver“ was accepted for publication in Journal of Biotechnology! Co-authors are Nathanael Raschzok, Susanne Rohn Mehmet H. Morgul, Ruth Schwartlander, Martina Mogl, Sonja Wollersheim, Katharina R. Schmitt and Igor M. Sauer. The paper is now available online.

Cell morphology, proliferation and motility, as well as mono- and heterotypic cell-to-cell interactions, are of increasing interest for in vitro experiments. However, tightly controlling culture conditions while simultaneously monitoring the same set of cells is complicated. Moreover, video-microscopy of distinct cells or areas of cells over a prolonged period of time represents a technical challenge. The SlideObserver was designed for cinemicrography of cells in co-and monoculture. The core elements of the system are the SlideReactors, miniaturised hollow fibre-based bioreactors operated in closed perfusion loops. Within the SlideReactors, cells can be cultured under standard and experimental conditions as well as in direct- and indirect co-culture. The independent perfusion loops enable controlled variation of parameters such as medium, pH, and oxygenation. A combined automated microscope stage and camera set-up allows for micrograph acquisition of multiple user-defined regions of interest within the bioreactor units. For proof of concept, primary cells (HUVEC, human hepatocytes) and cell lines (HuH7, THP-1) were cultured under stable and varying culture conditions, as well as in mono- and co-culture. The operational system enabled non-stop imaging and automated control of process parameters as well as elective manipulation of either reactor. As opposed to static culture systems or comparable devices for cinemicrographic analysis, the SildeObserver allows simultaneous morphological monitoring of an entire culture of cells in control and experimental bioreactors.

11th WAA & 6th ISFA World Congress

Gesine Pless took another major step in her career by defending her doctoral thesis "magna cum laude". Being (co-)author of more than 16 papers in peer reviewed journals she analysed primary human liver cells from donor organs unsuitable for transplantation cultivated in bioreactors. As each system contains cells originating from an individual organ, each bioreactor culture must be individually characterized. The objective of her study was to identify suitable decisive parameters for the evaluation of cell culture performance.

Dr. rer. medic. Gesine Pless

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Ruth Schwartlaender successfully defended her thesis "summa cum laude". After three years of extremely fruitful research and development she is (co-)author of 8 papers in peer reviewed journals (with more to come...) and gave numerous lectures at international meetings in the field of artificial organs and regenerative medicine. Her work was supported by research grants from the Berliner Graduiertenfoerderung (NaFOG) and the German Federal Ministry of Education and Research (BMBF - 0312111). Her latest results were published in the January issue of Tissue Engineering.

Dr. rer. medic. Ruth Schwartlaender

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Tissue Engineering published the article "Continuously Microscopically Observed and Process-Controlled Cell Culture Within the SlideReactor: Proof of a New Concept for Cell Characterization"  by R. Schwartlander, J. Schmid J, B. Brandenburg, E. Katenz, F.W. Vondran, G. Pless, X. Cheng X, A. Pascher A, P. Neuhaus P, and I.M. Sauer in the January 2007 issue.
Moreover, the editors have chosen one of the figures showing fluorsecent staining of primary human hepatocytes cultured within the SlideReactor as cover-art!
Certain cell types, especially primary human cells, favor a well-defined culture environment offering continuous supply of nutrients and oxygen and waste product removal. Several bioreactors based on special matrices or hollow fibers have been developed that provide such conditions. However, characterization of matrix re-organization or growth of tissue within these systems is possible only after culture termination. Evaluation of the influence of certain medium additives or culture conditions (e.g., temperature, oxygenation) on cell viability, expansion, and differentiation within these systems remains a challenging task. The SlideReactor, a miniaturized hollow fiber-based bioreactor, was developed to enable the observation of cells during culture. An operation concept offering predefined conditions for various cell types has been designed. For proof of concept, primary human cells (hepatocytes, fibroblasts, keratinocytes) and cell lines (HepG2, HuH7, C3A, WiDr, SkHep1) were cultured and observed. A series of experiments (n = 40) showed the feasibility of the set-up; determination of process parameters and continuous observation is possible. The SlideReactor may serve as a simple and cost-efficient tool for cell characterization and optimization of cell-culture conditions.

SlideReactor: Proof of concept

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The paper Cryopreservation of primary human hepatocytes – the benefit of trehalose as an additional cryoprotective agent by Ekaterina Katenz, Florian W.R. Vondran, Ruth Schwartlander, Gesine Pless, Xiaobing Gong, Xiandong Cheng, Peter Neuhaus and Igor M. Sauer is published in the January 2007 issue of Liver Transplantation. Problems with the limited availability of human hepatocytes for cell transplantation may be overcome by efficient cryopreservation techniques and formation of appropriate cell banking. In the present study we investigated the effect of the disaccharide trehalose on the cryopreservation of human hepatocytes. For analysis, liver cells were frozen in culture medium containing 10% DMSO that was supplemented with varying concentrations of trehalose. During the post-thawing culture period, viability, plating efficiency, total protein, cell proliferation, enzyme leakage, albumin and urea formation as well as phase I and II metabolism were analyzed. In the pilot study, among the concentrations investigated, 0.2 M trehalose showed the best overall outcome. Compared to the use of DMSO alone, we found significant improvement in post-thaw cell viability (62.9 ± 13 vs. 46.9 ± 11 %, p < 0.01) and plating efficiency (41.5 ± 18 vs. 17.6 ± 13 %, p < 0.01) in the trehalose group. The use of trehalose as an additive for cryopreserving human hepatocytes resulted in a significantly increased total protein level in the attached cells, higher secretion of albumin and a lower AST level after thawing. The use of trehalose as cryoprotective agent significantly improves the outcome of human hepatocyte cryopreservation.

Trehalose cryoprotective

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