F. Claussen, J.M.G.V. Gassner, S. Moosburner, D. Wyrwal, M. Nösser, P. Tang, L. Wegener, J. Pohl, A. Reutzel-Selke, R. Arsenic, J. Pratschke, I.M. Sauer, and N. Raschzok published their trecent work on "Dual versus single vessel normothermic ex vivo perfusion of rat liver grafts using metamizole for vasodilatation" in PLoS One 2020;15(7): e0235635.

Normothermic ex vivo liver perfusion (NEVLP) is a promising strategy to increase the donor pool in liver transplantation. Small animal models are essential to further investigate questions regarding organ preservation and reconditioning by NEVLP. A dual vessel small animal NEVLP (dNEVLP) model was developed using metamizole as a vasodilator and compared to conventional portovenous single vessel NEVLP (sNEVLP).

Livers of male Wistar rats were perfused with erythrocyte-supplemented culture medium for six hours by either dNEVLP via hepatic artery and portal vein or portovenous sNEVLP. dNEVLP was performed either with or without metamizole treatment. Perfusion pressure and flow rates were constantly monitored. Transaminase levels were determined in the perfusate at the start and after three and six hours of perfusion. Bile secretion was monitored and bile LDH and GGT levels were measured hourly. Histopathological analysis was performed using liver and bile duct tissue samples after perfusion.

Hepatic artery pressure was significantly lower in dNEVLP with metamizole administration. Compared to sNEVLP, dNEVLP with metamizole treatment showed higher bile production, lower levels of transaminases during and after perfusion as well as significantly lower necrosis in liver and bile duct tissue. Biochemical markers of bile duct injury showed the same trend.

Our miniaturized dNEVLP system enables normothermic dual vessel rat liver perfusion. The administration of metamizole effectively ameliorates arterial vasospasm allowing for six hours of dNEVLP, with superior outcome compared to sNEVLP.

Hepatocyte transplantation (HcTx) is a promising approach for the treatment of metabolic diseases in newborns and children. The most common application route is the portal vein, which is difficult to access in the newborn. Transfemoral access to the splenic artery for HcTx has been evaluated in adults, with trials suggesting hepatocyte translocation from the spleen to the liver with a reduced risk for thromboembolic complications. Using juvenile Göttingen minipigs, we aimed to evaluate feasibility of hepatocyte transplantation by transfemoral splenic artery catheterization, while providing insight on engraftment, translocation, viability, and thromboembolic complications. Four Göttingen Minipigs weighing 5.6 kg to 12.6 kg were infused with human hepatocytes (two infusions per cycle, 1.00E08 cells per kg body weight). Immunosuppression consisted of tacrolimus and prednisolone. The animals were sacrificed directly after cell infusion (n=2), 2 days (n=1), or 14 days after infusion (n=1). The splenic and portal venous blood flow was controlled via color-coded Doppler sonography. Computed tomography was performed on days 6 and 18 after the first infusion. Tissue samples were stained in search of human hepatocytes. Catheter placement was feasible in all cases without procedure-associated complications. Repetitive cell transplantations were possible without serious adverse effects associated with hepatocyte transplantation. Immunohistochemical staining has proven cell relocation to the portal venous system and liver parenchyma. However, cells were neither present in the liver nor the spleen 18 days after HcTx. Immunological analyses showed a response of the adaptive immune system to the human cells. We show that interventional cell application via the femoral artery is feasible in a juvenile large animal model of HcTx. Moreover, cells are able to pass through the spleen to relocate in the liver after splenic artery infusion. Further studies are necessary to compare this approach with umbilical or transhepatic hepatocyte administration.

"Hepatocyte Transplantation to the Liver via the Splenic Artery in a Juvenile Large Animal Model" was published in Cell Transplantation.
Authors are J. Siefert, K.H. Hillebrandt, S. Moosburner, P. Podrabsky, D. Geisel, T. Denecke, J.K. Unger, B. Sawitzki, S. Gül-Klein, S. Lippert, P. Tang, A. Reutzel-Selke, M.H. Morgul, A.W. Reske, S. Kafert-Kasting, W. Rüdinger, J. Oetvoes, J. Pratschke, I.M. Sauer, and N. Raschzok.

Today, Simon Moosburner successfully defended his doctoral thesis entitled "Erweiterung der Spenderpopulation bei Lebertransplantation: Klinischer Bedarf und Entwicklung eines Kleintier-Lebermaschinenperfusionssystems (Expanding the donor pool for liver transplantation: clinical need and development of small animal liver perfusion system)" summa cum laude !

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Three‐dimensional tissue cultures are important models for the study of cell‐cell and cell‐matrix interactions, as well as, to investigate tissue repair and reconstruction pathways. Therefore, we designed a reproducible and easy to handle printable bioreactor system (Teburu), that is applicable for different approaches of pathway investigation and targeted tissue repair using human tissue slices as a three‐dimensional cell culture model. Here, we definitively describe Teburu as a controlled environment to reseed a 500‐µm thick decellularized human liver slice using human mesenchymal stroma cells. During a cultivation period of eight days, Teburu, as a semi‐open and low consumption system, was capable to maintain steady pH and oxygenation levels. Its combination with additional modules delivers an applicability for a wide range of tissue engineering approaches under optimal culture conditions.

"Teburu—Open source 3D printable bioreactor for tissue slices as dynamic three‐dimensional cell culture models" was published in Artif Organs. 2019 Jun 18. doi: 10.1111/aor.13518. [Epub ahead of print]. Authors are A. Daneshgar, P. Tang, C. Remde, M. Lommel, S. Moosburner, U. Kertzscher, O. Klein, M. Weinhart, J. Pratschke, I.M. Sauer, and K.H. Hillebrandt.

Priv.-Doz. Dr. Moritz Schmelzle receives additional financial support for his project "CD39-dependent regulation of innate immune responses and modulation of exacerbated sterile inflammation in acute-on-chronic liver failure" (DFG Research Grant 299534341, SCHM2661/3-2).
Acute on chronic liver failure (ACLF) is defined as an acute hepatic insult in patients with chronic liver disease and is characterized by high death rates. Systemic inflammation is considered a hallmark of ACLF and can be linked to progression of liver failure and clinical deterioration. Criteria for ACLF and the systemic inflammatory response syndrome (SIRS) substantially overlap and support the assumption of mechanistic similarities between both syndromes. Thus, modulating inflammation and the linked immune responses in ACLF might help to restore homeostasis and improve of regenerative capacities of the injured liver.We hypothesize that the catalyzed hydrolysis of purinergic damage-associated molecular patterns (DAMPS), such as extracellular ATP, by the ectonucleotidase CD39 is crucially involved in the regulation of innate immune responses and the modulation of exacerbated sterile inflammation in ACLF. We here aim to describe characteristics and functions of monocyte subsets in ACLF and to investigate implications of purinergic signaling. We further plan to investigate the therapeutical relevance of non-classical monocytes and the immune-type ectonucleotidase CD39 in experimental ACLF. Finally, we will evaluate the clinical significance of cellular and non-cellular immune responses in ACLF patients enrolled in the GRAFT Trial.

Dr. Karl Hillebrandt and Dr. Matthäus Felsenstein successfully applied for the BIH Charité Junior Clinician Scientist Program. Karl Hillebrandt will continue his work on human decellularized liver slices as 3D platform for in vitro models of cholangiocellular carcinoma. Matthäus Felsenstein focusses on derivation of normal pancreatic duct cells from human primary tissue and their stepwise genetic modification in vitro using CRISPR/Cas9 .

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Martin Kluge is wearing excellent suits and successfully defended his doctoral thesis magna cum laude! He examined the effects of the magnetic field of magnetic resonance imaging (MRI) systems on cells labeled with micrometer-sized iron oxide particles.

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Today, Antje Butter successfully defended her doctoral thesis magna cum laude!
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Antje was involved in basic research with respect to liver decellularization and recellularization. A proprietary, customized bioreactor was established to repopulate decellularized rat livers with primary rat hepatocytes via the hepatic artery and to subsequently evaluate graft morphology and function during 7 days of ex vivo perfusion. More information via this link.

"Human Stem Cells Promote Liver Regeneration After Partial Hepatectomy in BALB/C Nude Mice" will be published in J Surg Res. 2019 (Mar 4;239:191-200. doi: 10.1016/j.jss.2019.02.010. [Epub ahead of print]).
Authors are S. Wabitsch, Ch. Benzing, F. Krenzien, K. Splith, P.K. Haber, A. Arnold, M. Nösser, C. Kamalia, F. Hermann, Ch. Günther, D. Hirsch, I.M. Sauer, J. Pratschke, and M. Schmelzle.

Mesenchymal stem cells (MSCs) have been suggested to augment liver regeneration after surgically and pharmacologically induced liver failure. To further investigate this we processed human bone marrow-derived MSC according to good manufacturing practice (GMP) and tested those cells for their modulatory capacities of metabolic alterations and liver regeneration after partial hepatectomy in BALB/c nude mice.

Human bone marrow-derived MSC attenuate metabolic alterations and improve liver regeneration after partial hepatectomy in BALB/c nude mice. Obtained results using GMP-processed human MSC suggest functional links between fat accumulation and hepatocyte proliferation, without any evidence for cellular homing. This study using GMP-proceeded MSC has important regulatory implications for an urgently needed translation into a clinical trial.