Dr. Nora Kammer & Dr. Kirsten Steinz
27 April 2012 - 20:09 Filed in: General
Nora defended her thesis "summa cum laude". She presented her results on labelling of primary human hepatocytes with micron-sized iron oxide particles in suspension culture suitable for large-scale preparation. In German her thesis is entitled „Markierung primärer humaner Hepatozyten mit mikroskaligen Eisenoxidpartikeln in temporärer Suspensionskultur“.
Kirsten defended her thesis „magna cum laude“. Her work is entitled „Evaluation der Applikationsrouten für die Leberzelltransplantation im Großtiermodell“
Congratulations!
Fast dynamic MRI for during liver cell Tx
01 September 2011 - 09:50 Filed in: Publications
Nathanael Raschzok’s paper concerning „Feasibility of fast dynamic MRI for non-invasive monitoring during ectopic liver cell transplantation to the spleen in a porcine model“ was accepted for publication in American Journal of Roentgenology . Authors are N. Raschzok, J. Pinkernelle, N. Billecke, K. Nehls, M. Powerski, I.M. Sauer and U. Teichgraber.
CARS microscopy of MPIO
10 September 2011 - 09:43 Filed in: Publications | Projects
The fruitful cooperation with the FOM Institute AMOLF in Masterdam resulted in the paper "CARS microscopy for the visualization of micrometer-sized iron oxide MRI contrast agents in living cells" (Rago G, Langer CM, Brackman C, Day JP, Domke KF, Raschzok N, Schmidt C, Sauer IM, Enejder A, Mogl MT, Bonn M.) published in Biomed Opt Express. 2011 Sep 1;2(9):2470-83.
Tat-peptide modified MPIO
01 April 2008 - 23:49 Filed in: Publications
Imaging of human hepatocytes via MPIO and MRI
02 April 2008 - 23:40 Filed in: Publications
CSAAS and MPIO-labelled cells
04 March 2009 - 23:24 Filed in: Publications
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.
Nathanael Raschzok defended thesis "summa cum laude"
25 April 2009 - 23:22 Filed in: General
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 his studies was to label primary human hepatocytes with micron-sized iron oxide particles (MPIOs), enabling the detection of cells by clinical magnetic resonance imaging (MRI). 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.
He also investigated techniques for evaluation of the particle uptake via continuum source atomic absorption spectrometry (CSAAS). 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. CSAAS enabled rapid quantification of particle load from small quantities of cells without extensive preparation steps. CSAAS could be used for quality control in a clinical setting of cell transplantation.
Haluk Morgül defended thesis "magna cum laude"
12 December 2009 - 23:09 Filed in: General
Modified nanoparticles & multimodal imaging
11 March 2010 - 23:08 Filed in: Publications
Cell transplantation is a major field in regenerative medicine and a promising alternative to whole organ transplantation. However, the process of cell engraftment is not yet fully understood and the hitherto achieved clinical outcome is limited. The aim of our study was to modify an aminosilan-coated nanoparticle for cell labeling and make it applicable for multimodal imaging using MRI, PET and fluorescent imaging. HIV-1 tat, linked FITC, and Gallium-68 were covalently bound to the particle and injected into Wistar rats. Animal-PET imaging was performed followed by MRI at 3.0T. Hepatic accumulation of the particles was proven by radionuclide distribution after 10 minutes in PET as well as in MRI over a 24 hour-period. Histological workup of the liver also revealed content of iron oxide particles in the reticuloendothelial system. Adjacent in vitro studies incubating hepatogenic HuH7 cells with the particles showed a rapid intracellular accumulation, clearly detectable by fluorescence microscopy and MRI. In conclusion our modified nanoparticle is stable under in vitro and in vivo conditions and is applicable for multimodal molecular imaging. Cellular labeling with this particle is possible and might help to get new insights into understanding the process of cell transplantation.
Monitoring cell transplantation in swine model via MRI
07 January 2011 - 19:22 Filed in: Publications
Liver cell transplantation (LCT) is a promising treatment approach for certain liver diseases, but clinical implementation requires methods for non-invasive follow-up. Labeling with superparamagnetic iron oxide particles can enable the detection of cells with magnetic resonance imaging (MRI). We investigated the feasibility of monitoring transplanted liver cells by MRI in a preclinical swine model and used this approach to evaluate different routes for cell application. Liver cells were isolated from landrace piglets and labeled with micron-sized iron oxide particles (MPIO) in adhesion. Labeled cells (n = 10), native cells (n = 3) or pure particles (n = 4) were transplanted to minipigs via intraportal infusion into the liver, direct injection into the splenic parenchyma, or intra-arterial infusion to the spleen. Recipients were investigated by repeated 3.0 Tesla MRI and computed tomography angiography up to 8 weeks after transplantation. Labeling with MPIO, which are known to have a strong effect on the magnetic field, enabled non-invasive detection of cell aggregates by MRI. Following intraportal application, which is commonly applied for clinical LCT, MRI was able to visualize the microembolization of transplanted cells in the liver that were not detected by conventional imaging modalities. Cells directly injected into the spleen were retained, whereas cell infusions intraarterially into the spleen led to translocation and engraftment of transplanted cells in the liver, with significantly fewer microembolisms compared to intraportal application. These findings demonstrate that MRI can be a valuable tool for non-invasive elucidation of cellular processes of LCT and - if clinically applicable MPIO are available - for monitoring of LCT under clinical conditions. Moreover, the results clarify mechanisms relevant for clinical practice of LCT, suggesting that the intra-arterial route to the spleen deserves further evaluation.
Labelling of hepatocytes in suspension culture
01 March 2011 - 19:21 Filed in: Publications
Protocols for labelling of hepatocytes with micron-sized iron oxide particles (MPIO) in adhesion culture enable cell detection using clinical Magnetic Resonance equipment. For clinical applications, large numbers of cells must be labelled in a simple and rapid manner, which requires new labelling protocols. The aim of this study was to investigate the feasibility of preparing MPIO-labelled primary human hepatocytes in a temporary suspension culture. Human hepatocytes were isolated from 16 donors and labelled with MPIO in suspension, using the Rotary Cell Culture System. Particle incorporation was investigated by light and electron microscopy. Cells were compared to adhesion culture-labelled and subsequently enzymatically resuspended cells. During a five-day culture period, hepatocyte-specific parameters of cell damage (aspartate aminotransferase and alanine aminotransferase) and metabolic activity (urea and albumin) were analysed. Suspension cultures showed a higher outcome in cell recovery compared to the conventional labelling method. When incubated with 180 particles/cell for four hours, the mean particle uptake was 28.8 particles/cell at a labelling efficiency of 95.1%. Labelling in suspension had no adverse effects on cell integrity or metabolic activity. In conclusion, labelling in suspension is a practicable method for fast and efficient preparation of large numbers of labelled cells that are suitable for clinical applications.