Antje Diestel's manuscript entitled "Tacrolimus and methylprednisolone prevent hypothermia induced endothelial dysfunction" has been accepted for publication in the Journal of Heart and Lung Transplantation. Co-authors are Nils Billecke, Joerg Roessler, Boris Schmitt, Silke Troeller, Ruth Schwartlander, Felix Berger, Igor Maximilian Sauer and Katharina Rose Luise Schmitt.
Hypothermia is used to preserve organs for transplant and it is the oldest method to protect organs during complex pediatric cardiac surgery. Loss of tissue function and tissue edema are common complications in children undergoing cardiac surgery and heart transplantation. The present study was designed to examine the effects of methylprednisolone (MP) and Tacrolimus (TAC) on endothelial cell function and morphology after deep hypothermia and rewarming. Human umbilical vein endothelial cells (HUVECs) were pretreated with MP and/orTAC and incubated either within a specially designed bioreactor or in monolayers. They were then exposed to a dynamic cooling and rewarming protocol. Immunocytochemistry, time lapse video microscopy within the SlideReactor bioreactor system, cell permeability and adherence assays and western blot analysis were performed. Confluent endothelial cells exposed to hypothermia displayed elongated cell shapes with intercellular gap formation, increased endothelial cell-layer permeability and loss in adherence. Upon rewarming, however, endothelial cell integrity was restored. Opening and closing of intercellular gaps was dependent on ERK 1/2 activation and connexin 43 (Cx43) expression. The combined treatment with MP and TAC inhibited these hypothermia-induced changes. These results suggest that MP and TAC inhibit hypothermia induced endothelial gap formation via pERK 1/2 inhibition and connexin 43 stabilization. Application of combined drugs that affect multiple targets may therefore be considered as a possible new therapeutic strategy to prevent endothelial dysfunction after hypothermia and rewarming.

As a result of the fruitful collaboration with the Institute for Analytical Sciences Berlin Nathanael Raschzok's paper on "Quantification of Cell Labelling with Micron-Sized Iron Oxide Particles Using Continuum Source Atomic Absorption Spectrometry" has been accepted by Tissue Engineering for publication. Co-authors are Nils Billecke, Nora N. Kammer, Mehmet H. Morgul, Michaela K. Adonopoulou, Igor M. Sauer, Stefan Florek, Helmut Becker-Ross, and Mao-Dong Huang.

Detection of cells after transplantation is necessary for quality control in regenerative medicine. Labelling with micron-sized iron oxide particles (MPIOs) enables non-invasive detection of single cells by magnetic resonance imaging. However, techniques for evaluation of the particle uptake are challenging. The aim of this study was to investigate continuum source atomic absorption spectrometry (CSAAS) for this purpose. Porcine liver cells were labelled with MPIOs and the iron concentration of the cell samples was investigated by a CSAAS spectrometer equipped with a Perkin-Elmer THGA graphite furnace. The weak iron line at 305.754 nm provides only about 1/600 sensitivity of the iron resonance line at 248.327 nm and was used for CSAAS measurements. Iron concentrations measured from labelled cells ranged from (5.8 ± 0.3) to (25.8 ± 0.9) pg Fe/cell, correlating to an uptake of (8.2 ± 0.5) to (25.7 ± 0.8) particles/cell. The results were verified by standardised morphometric evaluation. CSAAS enabled rapid quantification of particle load from small quantities of cells without extensive preparation steps. Thereby, CSAAS could be used for quality control in a clinical setting of cell transplantation.

After years of research in the field of hepatocyte isolation and hypothermic long-term culture Dominik Paul Modest successfully defended his thesis "magna cum laude".

February 5th, 2009 at 4 p.m. (Hörsaal 3, Lehrgebäude Charité - Campus Virchow Klinikum) Dr. I.M. Sauer will give his inaugurative lecture entitled "Künstliche Organe: Von der Vision kybernetischer Organismen zur medizinischen Realität".

The Berlin-Brandenburg School for Regenerative Therapies (BSRT) offers young talented scientists in Berlin and Brandenburg:
Best Publication Award: The award will be granted for the most outstanding paper for progress in Regenerative Medicine accepted by a peer review journal in the last two years. The award comprises 1.500 Euro.
Best Presentation Award: The award will be granted for the best poster presented at an international conference with a peer review system within the last two years. The award comprises 500 Euro.
Info & Contact: BSRT, Charité Campus Virchow-Klinikum, Augustenburger Platz 1, 13353 Berlin, E-Mail: award@bsrt.de, Web: www.bsrt.de

The Steering Committee of the Berlin-Brandenburg Center for Regenerative Therapies (BCRT) decided to involve Igor Sauer and his group as an Associated Investigator (AI).
The BCRT is a cooperative research institution of the Charite University Hospital in Berlin and Germany's largest research association, the Helmholtz Association. BCRT also receives generous financial support from the BMBF and the states of Berlin and Brandenburg, as well as from the Technology Foundations in Berlin and Brandenburg, the Future Fund Berlin and from various industry partners. More than 15 regional partners from science and industry are active members of the consortium at the BCRT.

Nathanel Raschzok's and Haluk Morgül's manuscript entitled "Imaging of Primary Human Hepatocytes Using Micron-Sized Iron Oxide Particles and Clinical Magnetic Resonance Tomography" has been accepted for publication in the Journal of Cellular and Molecular Medicine (impact factor: 6,55). Authors are Nathanael Raschzok, Mehmet H. Morgul, Jens Pinkernelle, Florian W.R. Vondran, Nils Billecke, Nora N. Kammer, Gesine Pless, Michaela K. Adonopoulou, Christian Leist, Lars Stelter, Ulf Teichgraber, Ruth Schwartlander and Igor M. Sauer. Nathanael Raschzok and Mehmet Haluk Morgul contributed equally to this work. The contribution of Ruth Schwartländer has to be emphasised as well. Transplantation of primary human hepatocytes is a promising approach in certain liver diseases. For visualisation of hepatocytes during and following cell application and the ability of a timely response to potential complications, a non-invasive modality for imaging of the transplanted cells has to be established. The aim of this study was to label primary human hepatocytes with micron-sized iron oxide particles (MPIOs), enabling the detection of cells by clinical magnetic resonance imaging (MRI). Primary human hepatocytes isolated from 13 different donors were used for labelling experiments. Following dose finding studies, hepatocytes were incubated with 30 particles/cell for 4 hours in adhesion culture. Particle incorporation was investigated via light, fluorescence and electron microscopy and labelled cells were fixed and analysed in an agarose suspension by a 3.0 Tesla MR scanner. Hepatocytes were enzymatically resuspended and analysed during a five-day reculture period for viability, total protein, enzyme leakage (AST, LDH) and metabolic activity (urea, albumin). A mean uptake of 18 particles/cell could be observed, and primary human hepatocytes were clearly detectable by MR instrumentation. The particle load was not affected by resuspension and showed no alternations during the culture period. Compared to control groups, labelling and resuspension had no adverse effects on viability, enzyme leakage and metabolic activity of human hepatocytes. Conclusion: The feasibility of preparing MPIO-labelled primary human hepatocytes detectable by clinical MR equipment was shown in vitro. MPIO-labelled cells could serve for basic research and quality control in the clinical setting of human hepatocyte transplantation.

Haluk Morgül and Nathanael Raschzok published their first results on "Tracking of primary human hepatocytes with clinical MRI: Initial results with Tat-peptide modified superparamagnetic iron oxide particles." in the March issue of IJAO (Int J Artif Organs 2008, 31:252-257): The transplantation of primary human hepatocytes is a promising approach in the treatment of specific liver diseases. However, little is known about the fate of the cells following application. Magnetic resonance imaging (MRI) could enable real-time tracking and long-term detection of transplanted hepatocytes. The use of superparamagnetic iron oxide particles as cellular contrast agents should allow for the non-invasive detection of labelled cells on high-resolution magnetic resonance images. Experiments were performed on primary human hepatocytes to transfer the method of detecting labelled cells via clinical MRI into human hepatocyte transplantation. For labelling, Tat-peptide modified nano-sized superparamagnetic MagForce particles were used. Cells were investigated via a clinical MR scanner at 3.0 Tesla and the particle uptake within single hepatocytes was estimated using microscopic examinations. The labelled primary human hepatocytes were clearly detectable by MRI, proving the feasibility of this new concept. Therefore, this method is a useful tool to investigate the effects of human hepatocyte transplantation and to improve safety aspects of this method.