TY - GEN A1 - Nghinaunye, Theopolina A1 - Waldeck, Peter A1 - Jung, C. G. H. A1 - Küpper, Jan-Heiner A1 - Jung, Friedrich A1 - Braune, Steffen T1 - Response of Arthrospira platensis to different temperatures regarding growth and biochemical composition T2 - Clinical Hemorheology and Microcirculation N2 - The growth of cyanobacteria can vary considerably depending on the ambient temperature. Since the optimal growth temperature for Arthrospira platensis (strain SAG21.99) is not yet known, this was investigated in the present study. The study revealed that a process temperature of 30°C seems to be optimal for the Arthrospira strain SAG21.99 cultivation in terms of a maximum biomass productivity. This was also true for the phycocyanin content which was at 30°C significantly higher than at 20 or 40°C. KW - Arthrospira platensis KW - growth KW - temperature KW - bioreactor Y1 - 2023 UR - https://content.iospress.com/articles/clinical-hemorheology-and-microcirculation/ch238104 U6 - https://doi.org/10.3233/CH-238104 SN - 1386-0291 SP - 1 EP - 7 ER - TY - GEN A1 - Krüger-Genge, Anne A1 - Köhler, Susanne A1 - Laube, Markus A1 - Haileka, Vanessa A1 - Lemm, Sandy A1 - Majchrzak, Karolina A1 - Kammerer, Sarah A1 - Schulz, Christian A1 - Storsberg, Joachim A1 - Pietzsch, Jens A1 - Küpper, Jan-Heiner A1 - Jung, Friedrich T1 - Anti-Cancer Prodrug Cyclophosphamide Exerts Thrombogenic Effects on Human Venous Endothelial Cells Independent of CYP450 Activation—Relevance to Thrombosis T2 - Cells N2 - Cancer patients are at a very high risk of serious thrombotic events, often fatal. The causes discussed include the detachment of thrombogenic particles from tumor cells or the adverse effects of chemotherapeutic agents. Cytostatic agents can either act directly on their targets or, in the case of a prodrug approach, require metabolization for their action. Cyclophosphamide (CPA) is a widely used cytostatic drug that requires prodrug activation by cytochrome P450 enzymes (CYP) in the liver. We hypothesize that CPA could induce thrombosis in one of the following ways: (1) damage to endothelial cells (EC) after intra-endothelial metabolization; or (2) direct damage to EC without prior metabolization. In order to investigate this hypothesis, endothelial cells (HUVEC) were treated with CPA in clinically relevant concentrations for up to 8 days. HUVECs were chosen as a model representing the first place of action after intravenous CPA administration. No expression of CYP2B6, CYP3A4, CYP2C9 and CYP2C19 was found in HUVEC, but a weak expression of CYP2C18 was observed. CPA treatment of HUVEC induced DNA damage and a reduced formation of an EC monolayer and caused an increased release of prostacyclin (PGI2) and thromboxane (TXA) associated with a shift of the PGI2/TXA balance to a prothrombotic state. In an in vivo scenario, such processes would promote the risk of thrombus formation. KW - cancer KW - cyclophosphamide KW - human umbilical vein endothelial cells KW - HUVEC KW - liver KW - cytochrome P450 enzymes (CYP) KW - thrombosis Y1 - 2023 UR - https://www.mdpi.com/2073-4409/12/15/1965 U6 - https://doi.org/10.3390/cells12151965 SN - 2073-4409 VL - 12 IS - 15 ER - TY - GEN A1 - Haas, Manuel A1 - Wirachowski, Karina A1 - Thibol, Lea A1 - Küpper, Jan-Heiner A1 - Schrenk, Dieter A1 - Fahrer, Jörg T1 - Potency ranking of pyrrolizidine alkaloids in metabolically competent human liver cancer cells and primary human hepatocytes using a genotoxicity test battery T2 - Archives of Toxicology N2 - Pyrrolizidine alkaloids (PAs) occur as contaminants in plant-based foods and herbal medicines. Following metabolic activation by cytochrome P450 (CYP) enzymes, PAs induce DNA damage, hepatotoxicity and can cause liver cancer in rodents. There is ample evidence that the chemical structure of PAs determines their toxicity. However, more quantitative genotoxicity data are required, particularly in primary human hepatocytes (PHH). Here, the genotoxicity of eleven structurally different PAs was investigated in human HepG2 liver cells with CYP3A4 overexpression and PHH using an in vitro test battery. Furthermore, the data were subject to benchmark dose (BMD) modeling to derive the genotoxic potency of individual PAs. The cytotoxicity was initially determined in HepG2-CYP3A4 cells, revealing a clear structure–toxicity relationship for the PAs. Importantly, experiments in PHH confirmed the structure-dependent toxicity and cytotoxic potency ranking of the tested PAs. The genotoxicity markers γH2AX and p53 as well as the alkaline Comet assay consistently demonstrated a structure-dependent genotoxicity of PAs in HepG2-CYP3A4 cells, correlating well with their cytotoxic potency. BMD modeling yielded BMD values in the range of 0.1–10 µM for most cyclic and open diesters, followed by the monoesters. While retrorsine showed the highest genotoxic potency, monocrotaline and lycopsamine displayed the lowest genotoxicity. Finally, experiments in PHH corroborated the genotoxic potency ranking, and revealed genotoxic effects even in the absence of detectable cytotoxicity. In conclusion, our findings strongly support the concept of grouping PAs into potency classes and help to pave the way for a broader acceptance of relative potency factors in risk assessment. KW - Cytotoxicity KW - Genotoxicity KW - Benchmark dose modeling KW - Pyrrolizidine alkaloids KW - Primary human hepatocytes KW - Potency ranking KW - γH2AX KW - p53 KW - DNA damage Y1 - 2023 UR - https://link.springer.com/article/10.1007/s00204-023-03482-8 U6 - https://doi.org/10.1007/s00204-023-03482-8 SN - 0340-5761 VL - 97 IS - 5 SP - 1413 EP - 1428 ER - TY - GEN A1 - Krüger-Genge, Anne A1 - Jung, Friedrich A1 - Hufert, Frank A1 - Jung, Ernst Michael A1 - Küpper, Jan-Heiner A1 - Storsberg, J. T1 - Effects of gut microbial metabolite trimethylamine N-oxide (TMAO) on platelets and endothelial cells T2 - Clinical Hemorheology and Microcirculation N2 - Thrombotic events result from different pathologies and are the underlying causes of severe diseases like stroke or myocardial infarction. Recent basic research now revealed a link between food uptake, food conversion and gut metabolism. Gut microbial production of trimethylamine N-oxide (TMAO) from dietary nutrients like choline, lecithin and L-carnitine was associated with the development of cardiovascular diseases. Within this review we give a systematic overview about the influence of TMAO on blood components like platelets and endothelial cells which both are involved as key players in thrombotic processes. In summary, a mechanistic correlation between the gut microbiome, TMAO and cardiovascular diseases becomes obvious and emphasizes to the significance of the intestinal microbiome. KW - Microbiome KW - trimethylamin-N-oxide KW - platelets KW - endothelial cells KW - atherosclerosis Y1 - 2020 UR - https://content.iospress.com/articles/clinical-hemorheology-and-microcirculation/ch209206 U6 - https://doi.org/10.3233/CH-209206 SN - 1875-8622 SN - 1386-0291 VL - 76 IS - 2 SP - 309 EP - 316 ER - TY - GEN A1 - Rahman, Ateeq A1 - Moola, Nyambe A1 - Küpper, Jan-Heiner T1 - Namibian algae species: A review of their distribution, medicinal uses and chemical constituents T2 - Journal of Cellular Biotechnology N2 - The use of indigenous or remote popular knowledge to identify new drugs against diseases or infections is a well-known approach in medicine. The inhabitants of coastal regions in Namibia and other African countries are known to prepare algae extracts for the treatment of disorders and ailments such as wounds, fever and stomach aches, as well as for the prevention of arrhythmia, cancer, and many other diseases. Algae survive in a competitive environment and, therefore, developed defense strategies that have resulted in a significant level of chemical structural diversity in various metabolic pathways. The exploration of these organisms for pharmaceutical, nutritional and medical purposes has provided important chemical candidates for the discovery of new agents against neglected tropical diseases and stimulated the use of sophisticated physical techniques. This current review provides a broad picture on the taxonomy, various medical and nutritional uses of algae, which thus should be of relevance for the African continent and underdeveloped countries in the Global South. Y1 - 2020 UR - https://content.iospress.com/articles/journal-of-cellular-biotechnology/jcb209010 U6 - https://doi.org/10.3233/JCB-209010 VL - 6 IS - 2 SP - 139 EP - 159 ER - TY - GEN A1 - Gehre, Christian P. A1 - Flechner, Marie A1 - Kammerer, Sarah A1 - Küpper, Jan-Heiner A1 - Coleman, Charles Dominic A1 - Püschel, Gerhard Paul A1 - Uhlig, Katja A1 - Duschl, Claus T1 - Real time monitoring of oxygen uptake of hepatocytes in a microreactor using optical microsensors T2 - Scientific Reports N2 - Most in vitro test systems for the assessment of toxicity are based on endpoint measurements and cannot contribute much to the establishment of mechanistic models, which are crucially important for further progress in this field. Hence, in recent years, much effort has been put into the development of methods that generate kinetic data. Real time measurements of the metabolic activity of cells based on the use of oxygen sensitive microsensor beads have been shown to provide access to the mode of action of compounds in hepatocytes. However, for fully exploiting this approach a detailed knowledge of the microenvironment of the cells is required. In this work, we investigate the cellular behaviour of three types of hepatocytes, HepG2 cells, HepG2-3A4 cells and primary mouse hepatocytes, towards their exposure to acetaminophen when the availability of oxygen for the cell is systematically varied. We show that the relative emergence of two modes of action, one NAPQI dependent and the other one transient and NAPQI independent, scale with expression level of CYP3A4. The transient cellular response associated to mitochondrial respiration is used to characterise the influence of the initial oxygen concentration in the wells before exposure to acetaminophen on the cell behaviour. A simple model is presented to describe the behaviour of the cells in this scenario. It demonstrates the level of control over the role of oxygen supply in these experiments. This is crucial for establishing this approach into a reliable and powerful method for the assessment of toxicity. KW - Biophysics KW - Biotechnology KW - Cell biology KW - Drug discovery Y1 - 2020 UR - https://www.nature.com/articles/s41598-020-70785-6 U6 - https://doi.org/10.1038/s41598-020-70785-6 SN - 2045-2322 VL - 10 ER - TY - GEN A1 - Steinbrecht, Susanne A1 - Kammerer, Sarah A1 - Küpper, Jan-Heiner T1 - HepG2 cells with recombinant cytochrome P450 enzyme overexpression: Their use and limitation as in vitro liver model T2 - Journal of Cellular Biotechnology Y1 - 2019 U6 - https://doi.org/10.3233/JCB-189013 SN - 2352-3697 SN - 2352-3689 VL - 5 IS - 1 SP - 55 EP - 64 ER - TY - GEN A1 - Schulz, Christian A1 - Kammerer, Sarah A1 - Küpper, Jan-Heiner T1 - NADPH-cytochrome P450 reductase expression and enzymatic activity in primary-like human hepatocytes and HepG2 cells for in vitro biotransformation studies T2 - Clinical Hemorheology and Microcirculation Y1 - 2019 U6 - https://doi.org/10.3233/CH-199226 SN - 1386-0291 VL - 73 IS - 1 SP - 249 EP - 260 ER - TY - GEN A1 - Hofman, Jakub A1 - Sorf, Ales A1 - Vagiannis, Dimitrios A1 - Sucha, Simona A1 - Kammerer, Sarah A1 - Küpper, Jan-Heiner A1 - Chen, Si A1 - Guo, Lei A1 - Ceckova, Martina A1 - Staud, Frantisek T1 - Brivanib Exhibits Potential for Pharmacokinetic Drug-Drug Interactions and the Modulation of Multidrug Resistance through the Inhibition of Human ABCG2 Drug Efflux Transporter and CYP450 Biotransformation Enzymes T2 - Molecular Pharmaceutics Y1 - 2019 U6 - https://doi.org/10.1021/acs.molpharmaceut.9b00361 VL - 16 IS - 11 SP - 4436 EP - 4450 ER - TY - GEN A1 - Hofman, Jakub A1 - Sorf, Ales A1 - Vagiannis, Dimitrios A1 - Sucha, Simona A1 - Novotna, Eva A1 - Kammerer, Sarah A1 - Küpper, Jan-Heiner A1 - Ceckova, Martina A1 - Staud, Frantisek T1 - Interactions of Alectinib with Human ATP-Binding Cassette Drug Efflux Transporters and Cytochrome P450 Biotransformation Enzymes: Effect on Pharmacokinetic Multidrug Resistance T2 - Drug Metabolism and Disposition Y1 - 2019 U6 - https://doi.org/10.1124/dmd.119.086975 SN - 1521-009X SN - 0090-9556 VL - 47 IS - 7 SP - 699 EP - 709 ER -