TY - GEN A1 - Jung, Friedrich A1 - Jung, Conrad H. G. A1 - Krüger-Genge, Anne A1 - Waldeck, Peter A1 - Küpper, Jan-Heiner T1 - Factors influencing the growth of Spirulina platensis in closed photobioreactors under CO₂ – O₂ conversion T2 - Journal of Cellular Biotechnology N2 - Since there is growing interest throughout the world in photosynthetic microbes as a potential source of food or food supplements, an assessment of factors which influence the biomass obtained in bioreactors, protein contents and constituents is important. This work reviews the autotrophic cultivation conditions of Spirulina platensis especially the dependency on the strain, the composition of the nutrient solution, pH, temperature of the medium, light intensity and color as well as exposure rhythm, the flow rate and composition of the aerating gas mixture and the bubble size, the content of oxygen, CO₂ and HCO₃ in the medium and last but not least from the optical density of the spirulina suspension during growth. KW - spirulina platensis KW - influencing factors KW - temperature KW - light intensity KW - wave length Y1 - 2019 U6 - https://doi.org/10.3233/JCB-199004 SN - 2352-3697 SN - 2352-3689 VL - 5 IS - 2 SP - 125 EP - 134 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 - 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 - Schulte-Hubbert, Ruth A1 - Küpper, Jan-Heiner A1 - Thomas, Adam D. A1 - Schrenk, Dieter T1 - Estragole: DNA adduct formation in primary rat hepatocytes and genotoxic potential in HepG2-CYP1A2 cells T2 - Toxicology N2 - Estragole is a natural constituent in herbs and spices and in products thereof such as essential oils or herbal teas. After cytochrome P450-catalyzed hydroxylation and subsequent sulfation, estragole acts as a genotoxic hepatocarcinogen forming DNA adducts in rodent liver. Because of the genotoxic mode of action and the widespread occurrence in food and phytomedicines a refined risk assessment for estragole is needed. We analyzed the time- and concentration-dependent levels of the DNA adducts N2-(isoestragole-3‘-yl)-2‘-desoxyguanosine (E3′N2dG) and N6-(isoestragole-3‘-yl)-desoxyadenosine (E3′N6dA), reported to be the major adducts formed in rat liver, in rat hepatocytes (pRH) in primary culture after incubation with estragole. DNA adduct levels were measured via UHPLC-ESI-MS/MS using stable isotope dilution analysis. Both adducts were formed in pRH and could already be quantified after an incubation time of 1 h (E3′N6dA at 10 μM, E3′N2dG at 1μM estragole). E3′N2dG, the main adduct at all incubation times and concentrations, could be detected at estragole concentrations < 0.1 μM after 24 h and < 0.5 μM after 48 h. Adduct levels were highest after 6 h and showed a downward trend at later time-points, possibly due to DNA repair and/or apoptosis. While the concentration-response characteristics of adduct formation were apparently linear over the whole concentration range, strong indication for marked hypo-linearity was obtained when the modeling was based on concentrations < 1 μM only. In the micronucleus assay no mutagenic potential of estragole was found in HepG2 cells whereas in HepG2-CYP1A2 cells 1 μM estragole led to a 3.2 fold and 300 μM to a 7.1 fold increase in micronuclei counts. Our findings suggest the existence of a ‘practical threshold’ dose for DNA adduct formation as an initiating key event of the carcinogenicity of estragole indicating that the default assumption of concentration-response-linearity is questionable, at least for the two major adducts studied here. KW - Estragole KW - Carcinogenicity KW - DNA adducts KW - Genotoxicity KW - Hepatoma KW - Liver cells Y1 - 2020 UR - https://www.sciencedirect.com/science/article/pii/S0300483X20302055 U6 - https://doi.org/10.1016/j.tox.2020.152566 SN - 0300-483X VL - 444 ER - TY - GEN A1 - Rutz, Lukas A1 - Gao, Lan A1 - Küpper, Jan-Heiner A1 - Schrenk, Dieter T1 - Structure-dependent genotoxic potencies of selected pyrrolizidine alkaloids in metabolically competent HepG2 cells T2 - Archives of Toxicology N2 - 1,2-unsaturated pyrrolizidine alkaloids (PAs) are natural plant constituents comprising more than 600 different structures. A major source of human exposure is thought to be cross-contamination of food, feed and phytomedicines with PA plants. In humans, laboratory and farm animals, certain PAs exert pronounced liver toxicity and can induce malignant liver tumors in rodents. Here, we investigated the cytotoxicity and genotoxicity of eleven PAs belonging to different structural classes. Although all PAs were negative in the fluctuation Ames test in Salmonella, they were cytotoxic and induced micronuclei in human HepG2 hepatoblastoma cells over-expressing human cytochrome P450 3A4. Lasiocarpine and cyclic diesters except monocrotaline were the most potent congeners both in cytotoxicity and micronucleus assays with concentrations below 3 μM inducing a doubling in micronuclei counts. Other open di-esters and all monoesters exhibited weaker or much weaker geno- and cytotoxicity. The findings were in agreement with recently suggested interim Relative Potency (iREP) factors with the exceptions of europine and monocrotaline. A more detailed micronuclei analysis at low concentrations of lasiocarpine, retrorsine or senecionine indicated that pronounced hypolinearity of the concentration–response curves was evident for retrorsine and senecionine but not for lasiocarpine. Our findings show that the genotoxic and cytotoxic potencies of PAs in a human hepatic cell line vary in a structure-dependent manner. Both the low potency of monoesters and the shape of prototype concentration–response relationships warrant a substance- and structure-specific approach in the risk assessment of PAs. KW - Genotoxicity KW - Liver cells KW - Micronuclei KW - Mutagenicity KW - Pyrrolizidine alkaloids KW - Relative potencies Y1 - 2020 UR - https://link.springer.com/article/10.1007/s00204-020-02895-z U6 - https://doi.org/10.1007/s00204-020-02895-z SN - 0340-5761 SN - 1432-0738 VL - 94 IS - 12 SP - 4159 EP - 4172 ER - TY - GEN A1 - Künzel, Stephan R. A1 - Rausch, Johanna S. E. A1 - Schäffer, Charlotte A1 - Hoffmann, Maximilian A1 - Künzel, Karolina A1 - Klapproth, Erik A1 - Kant, Theresa A1 - Herzog, Natalie A1 - Küpper, Jan-Heiner A1 - Lorenz, Kristina A1 - Dudek, Svenja A1 - Emig, Ramona A1 - Ravens, Ursula A1 - Rog‐Zielinska, Eva A. A1 - Peyronnet, Rémi A1 - El-Armouche, Ali T1 - Modeling atrial fibrosis in vitro - Generation and characterization of a novel human atrial fibroblast cell line T2 - FEBS Open Bio N2 - Atrial fibrillation (AF) is regularly accompanied by cardiac fibrosis and concomitant heart failure. Due to the heterogeneous nature and complexity of fibrosis, the knowledge about the underlying mechanisms is limited, which prevents effective pharmacotherapy. A deeper understanding of cardiac fibroblasts is essential to meet this need. We previously described phenotypic and functional differences between atrial fibroblasts from patients in sinus rhythm and with AF. Herein, we established and characterized a novel human atrial fibroblast line, which displays typical fibroblast morphology and function comparable to primary cells but with improved proliferation capacity and low spontaneous myofibroblast differentiation. These traits make our model suitable for the study of fibrosis mechanisms and for drug screening aimed at developing effective antifibrotic pharmacotherapy. KW - cardiovascular disease KW - cell culture KW - cell lines KW - fibroblasts KW - fibrosis KW - heart Y1 - 2020 U6 - https://doi.org/10.1002/2211-5463.12896 SN - 2211-5463 VL - 10 IS - 7 SP - 1210 EP - 1218 ER - TY - GEN A1 - Jung, Friedrich A1 - Krieger, Volker A1 - Hufert, Frank A1 - Küpper, Jan-Heiner T1 - How we should respond to the Coronavirus SARS-CoV-2 outbreak: A German perspective T2 - Clinical Hemorheology and Microcirculation N2 - BACKGROUND: In the early phase of the COVID-19 pandemic Germany missed to set up efficient containment measures. Consequently, the number of cases increased exponentially until a lockdown was implemented to suppress the spread of SARS-CoV-2. Fortunately, Germany has a high capability for coronavirus lab testing and more than 30,000 ICU beds. These capabilities and the lockdown turned out to be an advantage to combat the pandemic and to prevent a health-system overload. AIM: The aim was to predict the plateau day of SARS-CoV-2 infections or deaths. RESULTS: The effect on the viral spread of the German measures taken and the impact on the peak of new infection cases is shown. By normalizing daily case numbers, the plateau day of the current outbreak in Germany could be calculated to be reached at April 12, 2020 (day 103 of 2020). CONCLUSION: Normalized case number curves are helpful to predict the time point at which no further new infections will occur if the epidemic situation remains stable. Upon reaching the plateau day during a lockdown phase, a residual time-period of about 2-3 weeks can be utilized to prepare a safe unlocking period. As can be learned from Asian countries such as South Korea and Taiwan there must be strict rules to keep the risk of infection low. Those include social distancing, face mask wearing in combination with digital contact tracing and serosurveillance studies. Following those rules, a safe dance around the infection curve allows to keep the population at a reduced infection rate. KW - Corona virus KW - SARS-CoV-2 KW - COVID-19 KW - herd immunity KW - hammer and dance strategy Y1 - 2020 UR - https://content.iospress.com/articles/clinical-hemorheology-and-microcirculation/ch209004 U6 - https://doi.org/10.3233/CH-209004 SN - 1875-8622 SN - 1386-0291 VL - 74 IS - 4 SP - 363 EP - 372 ER - TY - GEN A1 - Küpper, Jan-Heiner A1 - Jung, Friedrich A1 - Krieger, Volker A1 - Hufert, Frank T1 - A comparison of mortality rates between European and Asian States T2 - Clinical Hemorheology and Microcirculation Y1 - 2020 U6 - https://doi.org/10.3233/CH-209008 SN - 1875-8622 SN - 1386-0291 VL - 75 IS - 1 SP - 3 EP - 5 ER - TY - GEN A1 - Jung, Friedrich A1 - Krüger-Genge, Anne A1 - Franke, Ralf-Peter A1 - Hufert, Frank A1 - Küpper, Jan-Heiner T1 - COVID-19 and the endothelium T2 - Clinical Hemorheology and Microcirculation N2 - There is growing evidence that COVID-19 not only affects the lungs but beyond that the endothelial system. Recent studies showed that this can lead to microcirculatory impairments and in consequence to functional disorders of all inner organs. The combination of endothelial dysfunction with a generalized inflammatory state and complement elements may together contribute to the overall pro-coagulative state described in COVID-19 patients leading to venular as well as to arteriolar occlusions. KW - COVID-19 KW - endocytosis KW - endothelial cell dysfunction KW - endotheliitis Y1 - 2020 UR - https://content.iospress.com/articles/clinical-hemorheology-and-microcirculation/ch209007 U6 - https://doi.org/10.3233/CH-209007 SN - 1875-8622 SN - 1386-0291 VL - 75 IS - 1 SP - 7 EP - 11 ER - TY - GEN A1 - Jung, Friedrich A1 - Krieger, Volker A1 - Hufert, Frank A1 - Küpper, Jan-Heiner T1 - Herd immunity or suppression strategy to combat COVID-19 T2 - Clinical Hemorheology and Microcirculation N2 - Some months ago, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) broke out in Wuhan, China, and spread rapidly around the world. Some states, such as the Netherlands, Germany, Great Britain, Sweden and the USA initially focused on keeping the restrictions for economy and society as low as possible. The responsible authorities were of the opinion - and still are e.g. in Sweden - that it is sufficient enough to protect particularly vulnerable persons such as the elderly or people with pre-existing conditions. The idea behind this is that as soon as 60 to 70 percent of the population is infected with a pathogen, a so-called “herd immunity” has developed. However, the increasing numbers of deaths and modelling studies showed the expected overload of the hospitals. Therefore, most countries decided for a temporary lockdown with the exception of Sweden. Based on the number of the total population, three times more people died from COVID-19 in Sweden (2679 deaths per 10 million inhabitants) compared to Germany (6848 deaths per 80 million inhabitants). The comparison Sweden versus Taiwan is even worse because 1072 times more people died in Sweden based on the number of the population (6 deaths per 24 million inhabitants). KW - COVID-19 KW - strategy KW - Sweden KW - Taiwan KW - Germany Y1 - 2020 UR - https://content.iospress.com/articles/clinical-hemorheology-and-microcirculation/ch209006 U6 - https://doi.org/10.3233/CH-209006 SN - 1875-8622 SN - 1386-0291 VL - 75 IS - 1 SP - 13 EP - 17 ER -