Tissue Engineering (Part C: Methods) accepted our paper entitled "The predictive value of the LiMAx-test for the isolation of primary human hepatocytes".
Authors are R.D. Major, M. Kluge, M. Jara, M. Nösser, R. Horner, J. Gassner, B. Struecker, P. Tang, S. Lippert, A. Reutzel-Selke, D. Geisel, T. Denecke, M. Stockmann, J. Pratschke, I.M. Sauer, and N. Raschzok.

The need for primary human hepatocytes is constantly growing, for basic research as well as for therapeutic applications. However, the isolation outcome strongly depends on the quality of liver tissue, and we are still lacking a preoperative test that allows the prediction of the hepatocyte isolation outcome. Here we evaluated the “maximal liver function capacity test” (LiMAx) as predictive test for the quantitative and qualitative outcome of hepatocyte isolation. This test is already used in clinical routine to measure preoperative and to predict postoperative liver function.
The patient’s preoperative mean LiMAx was obtained from the patient records and preoperative CT and MRI images were used to calculate the whole liver volume in order to adjust the mean LiMAx. The outcome parameters of the hepatocyte isolation procedures were analyzed in correlation with the adjusted mean LiMAx.
Primary human hepatocytes were isolated from partial hepatectomies (n=64).
From these 64 hepatectomies we included 48 to our study and correlated their isolation outcome parameters with volume corrected LiMAx values. From a total of 11 hepatocyte isolation procedures, metabolic parameters (albumin, urea and aspartate aminotransferase) were assessed during the hepatocyte cultivation period of 5 days. The volume adjusted mean LiMAx showed a significant positive correlation with the total cell yield (p= 0.049;r= 0.242;n= 48). The correlations of volume adjusted LiMAx values with viable cell yield and cell viability did not reach statistical significance. A sub-group analysis of isolations from patients with colorectal metastasis revealed a significant correlation between volume adjusted mean LiMAx and total cell yield (p= 0.012;r= 0.488;n= 21) and viable cell yield (p=0.034;r=0.405;n=21). Whereas a sub-group analysis of isolations of patients with carcinoma of the biliary tree showed significant correlations of volume adjusted mean LiMAx with cell viability (r= 0.387;p= 0.046;n=20) and lacked significant correlations with total cell yield (r= - 0.060;p= 0.401;n=20) and viable cell yield (r= 0.012;p= 0.480;n=20). The volume-adjusted mean LiMAx did not show a significant correlation with any of the metabolic parameters. In conclusion, the LiMAx-test might be a useful tool to predict the quantitative outcome of hepatocyte isolation, as long as underlying liver disease is taken into consideration.

Our paper entitled "The magnetic field of magnetic resonance imaging systems does not affect cells labeled with micrometer-sized iron oxide particles," has been accepted for publication in Tissue Engineering, Part C: Methods. Authors are Martin Kluge, Annekatrin Leder, Karl H. Hillebrandt, Benjamin Struecker, Dominik Geisel, Timm Denecke, Rebeka D. Major, Anja Reutzel-Selke, Peter Tang, Steffen Lippert, Christian Schmidt, Johann Pratschke, Igor M. Sauer, and Nathanael Raschzok.

Labeling using iron oxide particles enables cell tracking via magnetic resonance imaging (MRI). However, the magnetic field can affect the particle-labeled cells. Here, we investigated the effects of a clinical MRI system on primary human hepatocytes labeled using micrometer-sized iron oxide particles (MPIOs).  HuH7 tumor cells were incubated with increasing concentrations of biocompatible, silica-based, micron-sized iron oxide-containing particles (sMPIO; 40 – 160 particles/cell). Primary human hepatocytes were incubated with 100 sMPIOs/cell. The particle-labeled cells and the native cells were imaged using a clinical 3.0-T MRI system, whereas the control groups of the labeled and unlabeled cells were kept at room temperature without exposure to a magnetic field. Viability, formation of reactive oxygen species, aspartate aminotransferase leakage, and urea and albumin synthesis were assessed over a culture period of 5 days. 
The dose finding study showed no adverse effects of the sMPIO labeling on HuH7 cells. MRI had no adverse effects on the morphology of the sMPIO-labeled primary human hepatocytes. Imaging using the T1- and T2-weighted sequences did not affect the viability, transaminase leakage, formation of reactive oxygen species, or metabolic activity of the sMPIO-labeled cells or the unlabeled, primary human hepatocytes. sMPIOs did not induce adverse effects on the labeled cells under the conditions of the magnetic field of a clinical MRI system.

Tissue Engineering, Part C: Methods accepted our paper „Human hepatocyte isolation: Does portal vein embolization affect the outcome?“ Authors are Martin Kluge, Anja Reutzel-Selke, Hendrik Napierala, Karl H. Hillebrandt, Rebeka D. Major, Benjamin Struecker, Annekatrin Leder, Jeffrey Siefert, Peter Tang, Steffen Lippert, Daniel Seehofer, Johann Pratschke, Igor M. Sauer und Nathanael Raschzok.

Primary human hepatocytes are widely used for basic research, pharmaceutical testing, and therapeutic concepts in regenerative medicine. Human hepatocytes can be isolated from resected liver tissue. Preoperative portal vein embolization (PVE) is increasingly used to decrease the risk of delayed postoperative liver regeneration by induction of selective hypertrophy of the future remnant liver tissue. The aim of this study was to investigate the effect of PVE on the outcome of hepatocyte isolation. Primary human hepatocytes were isolated from liver tissue obtained from partial hepatectomies (n=190) using the two-step collagenase perfusion technique followed by Percoll purification. Of these hepatectomies, 27 isolations (14.2%) were performed using liver tissue obtained from patients undergoing PVE prior to surgery. All isolations were characterized using parameters that had been described in the literature as relevant for the outcome of hepatocyte isolation. The PVE and non-PVE groups were similar in regard to donor parameters (sex, age, indication for surgery), isolation parameters (liver weight, cold ischemic time), and the quality of the liver tissue. The mean initial viable cell yield did not differ between the PVE and non-PVE groups (10.16±2.03x106 cells/g vs. 9.70±0.73 x106 cells/g, p=0.499). The initial viability was slightly better in the PVE-group (77.8 ±2.03% vs. 74.4 ±1.06%). The mean viable cell yield (p=0.819) and the mean viability (p=0.141) after Percoll purification did not differ between the groups. PVE had no effect on enzyme leakage and metabolic activity of cultured hepatocytes.  Although PVE leads to drastic metabolic alterations and changes in hepatic blood flow, embolized liver tissue is a suitable source for the isolation of primary human hepatocytes and is equivalent to untreated liver tissue in regard to cell yield and viability.

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.