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 - TY - GEN A1 - Steinbrecht, Susanne A1 - Kiebist, Jan A1 - König, Rosalie A1 - Thiessen, Markus A1 - Schmidtke, Kai-Uwe A1 - Kammerer, Sarah A1 - Küpper, Jan-Heiner A1 - Scheibner, Katrin T1 - Synthesis of cyclophosphamide metabolites by a peroxygenase from Marasmius rotula for toxicological studies on human cancer cells T2 - AMB Express N2 - Cyclophosphamide (CPA) represents a widely used anti-cancer prodrug that is converted by liver cytochrome P450 (CYP) enzymes into the primary metabolite 4-hydroxycyclophosphamide (4-OH-CPA), followed by non-enzymatic generation of the bioactive metabolites phosphoramide mustard and acrolein. The use of human drug metabolites as authentic standards to evaluate their toxicity is essential for drug development. However, the chemical synthesis of 4-OH-CPA is complex and leads to only low yields and undesired side products. In past years, fungal unspecific peroxygenases (UPOs) have raised to powerful biocatalysts. They can exert the identical selective oxyfunctionalization of organic compounds and drugs as known for CYP enzymes with hydrogen peroxide being used as sole cosubstrate. Herein, we report the efficient enzymatic hydroxylation of CPA using the unspecific peroxygenase from Marasmius rotula (MroUPO) in a simple reaction design. Depending on the conditions used the primary liver metabolite 4-OH-CPA, its tautomer aldophosphamide (APA) and the overoxidized product 4-ketocyclophosphamide (4-keto-CPA) could be obtained. Using a kinetically controlled approach 4-OH-CPA was isolated with a yield of 32% (purity > 97.6%). Two human cancer cell lines (HepG2 and MCF-7) were treated with purified 4-OH-CPA produced by MroUPO (4-OH-CPAUPO). 4-OH-CPAUPO–induced cytotoxicity as measured by a luminescent cell viability assay and its genotoxicity as measured by γH2AX foci formation was not significantly different to the commercially available standard. The high yield of 4-OH-CPAUPO and its biological activity demonstrate that UPOs can be efficiently used to produce CYP-specific drug metabolites for pharmacological assessment. KW - Biocatalysis KW - Cyclophosphamide KW - Human drug metabolites KW - Peroxygenase KW - Toxicity Y1 - 2020 UR - https://amb-express.springeropen.com/articles/10.1186/s13568-020-01064-w U6 - https://doi.org/10.1186/s13568-020-01064-w SN - 2191-0855 VL - 10 ER - TY - GEN A1 - Vagiannis, Dimitrios A1 - Novotna, Eva A1 - Skarka, Adam A1 - Kammerer, Sarah A1 - Küpper, Jan-Heiner A1 - Chen, Si A1 - Guo, Lei A1 - Staud, Frantisek A1 - Hofman, Jakub T1 - Ensartinib (X-396) Effectively Modulates Pharmacokinetic Resistance Mediated by ABCB1 and ABCG2 Drug Efflux Transporters and CYP3A4 Biotransformation Enzyme T2 - Cancers N2 - Ensartinib (X-396) is a promising tyrosine kinase inhibitor currently undergoing advanced clinical evaluation for the treatment of non-small cell lung cancer. In this work, we investigate possible interactions of this promising drug candidate with ATP-binding cassette (ABC) drug efflux transporters and cytochrome P450 biotransformation enzymes (CYPs), which play major roles in multidrug resistance (MDR) and pharmacokinetic drug-drug interactions (DDIs). Accumulation studies showed that ensartinib is a potent inhibitor of ABCB1 and ABCG2 transporters. Additionally, incubation experiments with recombinant CYPs showed that ensartinib significantly inhibits CYP3A4 and CYP2C9. Subsequent molecular docking studies confirmed these findings. Drug combination experiments demonstrated that ensartinib synergistically potentiates the antiproliferative effects of daunorubicin, mitoxantrone, and docetaxel in ABCB1, ABCG2, and CYP3A4-overexpressing cellular models, respectively. Advantageously, ensartinib’s antitumor efficiency was not compromised by the presence of MDR-associated ABC transporters, although it acted as a substrate of ABCB1 in Madin-Darby Canine Kidney II (MDCKII) monolayer transport assays. Finally, we demonstrated that ensartinib had no significant effect on the mRNA-level expression of examined transporters and enzymes in physiological and lung tumor cellular models. In conclusion, ensartinib may perpetrate clinically relevant pharmacokinetic DDIs and modulate ABCB1-, ABCG2-, and CYP3A4-mediated MDR. The in vitro findings presented here will provide a valuable foundation for future in vivo investigations. KW - ensartinib KW - cancer KW - multidrug resistance KW - drug-drug interaction KW - ABC transporter KW - cytochrome P450 Y1 - 2020 UR - https://www.mdpi.com/2072-6694/12/4/813 U6 - https://doi.org/10.3390/cancers12040813 SN - 2072-6694 VL - 12 IS - 4 ER - TY - GEN A1 - Lau, S. A1 - Rangarajan, R. A1 - Krüger-Genge, Anne A1 - Braune, Steffen A1 - Küpper, Jan-Heiner A1 - Lendlein, Andreas A1 - Jung, Friedrich T1 - Age-related morphology and function of human arterial endothelial cells T2 - Clinical Hemorheology and Microcirculation N2 - Endothelialization of cardiovascular implants is regarded as a promising strategy for long-term compatibility. While umbilical vein endothelial cells are typically applied in research, human arterial endothelial cells (HAEC) from elderly donors would be the obvious source for autologous cellularization strategies. In our approach, HAEC from 16 donors of varying age (16–63 years) were divided into two groups (<30 years and >30 years) and analyzed regarding morphology, viability, proliferation, function and senescence status. No age-related differences were found regarding morphology, viability, density, prostacyclin and nitrite secretion or collagen and laminin production. However, the metabolic activity was slightly decreased (p = 0.0374) and the membrane integrity marginally impaired (p = 0.0404) in cells from older donors. Two out of three senescence assays detected more senescence markers in cells from older donors. According to the assays applied here, HAEC from young and elderly donors up to the age of 63 years could be judged equally suitable for autologous cellularization strategies. However, this finding should be regarded with caution due to the extremely large variability between individual donors. Further studies comprising a larger sample size are necessary to investigate this issue more thoroughly. KW - Cardiovascular implants KW - arterial endothelial cells KW - aging KW - senescence KW - donor variability Y1 - 2020 UR - https://content.iospress.com/articles/clinical-hemorheology-and-microcirculation/ch199238 U6 - https://doi.org/10.3233/CH-199238 SN - 1875-8622 SN - 1386-0291 VL - 74 IS - 1 SP - 93 EP - 107 ER - TY - GEN A1 - Krüger-Genge, Anne A1 - Steinbrecht, Susanne A1 - Jung, Conrad H. G. A1 - Westphal, Sophia A1 - Klöpzig, Stefanie A1 - Waldeck, Peter A1 - Küpper, Jan-Heiner A1 - Storsberg, J. A1 - Jung, Friedrich T1 - Arthrospira platensis accelerates the formation of an endothelial cell monolayer and protects against endothelial cell detachment after bacterial contamination T2 - Clinical Hemorheology and Microcirculation N2 - Within the last years a comprehensive number of scientific studies demonstrated beneficial effect of Arthropira platensis (AP) as dietary supplement due to a high content of proteins, minerals and vitamins. Positive effects like promoting the immune system, reducing inflammation and an anti-oxidant capacity are reported. In this study, the effect of an aqueous AP extract on primary human venous endothelial cells (HUVEC) was investigated. In addition, the effect of AP on HUVEC treated with a bacterial toxin (lipopolysaccharide, LPA), inducing an activation of HUVEC and cellular detachment, was analyzed. Depending on the concentration of AP extract a significantly accelerated formation of an endothelial cell monolayer was observed. Furthermore, the detachment of HUVEC after LPA addition was dramatically reduced by AP. In conclusion, the data are promising and indicatory for an application of Arthrospira platensis in the clinical field. KW - Arthrospira platensis KW - endothelial cells KW - xCELLigence system Y1 - 2021 UR - https://content.iospress.com/articles/clinical-hemorheology-and-microcirculation/ch201096 U6 - https://doi.org/10.3233/CH-201096 SN - 1386-0291 VL - 78 IS - 2 SP - 151 EP - 161 ER - TY - GEN A1 - Schulz, Christian A1 - Krüger-Genge, Anne A1 - Lendlein, Andreas A1 - Küpper, Jan-Heiner A1 - Jung, Friedrich T1 - Potential Effects of Nonadherent on Adherent Human Umbilical Venous Endothelial Cells in Cell Culture T2 - International Journal of Molecular Science N2 - The adherence and shear-resistance of human umbilical venous endothelial cells (HUVEC) on polymers is determined in vitro in order to qualify cardiovascular implant materials. In these tests, variable fractions of HUVEC do not adhere to the material but remain suspended in the culture medium. Nonadherent HUVEC usually stop growing, rapidly lose their viability and can release mediators able to influence the growth and function of the adherent HUVEC. The aim of this study was the investigation of the time dependent behaviour of HUVEC under controlled nonadherent conditions, in order to gain insights into potential influences of these cells on their surrounding environment in particular adherent HUVEC in the context of in vitro biofunctionality assessment of cardiovascular implant materials. Data from adherent or nonadherent HUVEC growing on polystyrene-based cell adhesive tissue culture plates (TCP) or nonadhesive low attachment plates (LAP) allow to calculate the number of mediators released into the culture medium either from adherent or nonadherent cells. Thus, the source of the inflammatory mediators can be identified. For nonadherent HUVEC, a time-dependent aggregation without further proliferation was observed. The rate of apoptotic/dead HUVEC progressively increased over 90% within two days. Concomitant with distinct blebbing and loss of membrane integrity over time, augmented releases of prostacyclin (PGI2, up to 2.91 ± 0.62 fg/cell) and platelet-derived growth factor BB (PDGF-BB, up to 1.46 ± 0.42 fg/cell) were detected. The study revealed that nonadherent, dying HUVEC released mediators, which can influence the surrounding microenvironment and thereby the results of in vitro biofunctionality assessment of cardiovascular implant materials. Neglecting nonadherent HUVEC bears the risk for under- or overestimation of the materials endothelialization potential, which could lead to the loss of relevant candidates or to uncertainty with regard to their suitability for cardiac applications. One approach to minimize the influence from nonadherent endothelial cells could be their removal shortly after observing initial cell adhesion. However, this would require an individual adaptation of the study design, depending on the properties of the biomaterial used. KW - human venous endothelial cells KW - adherent KW - non-adherent KW - viability KW - mediator release Y1 - 2021 UR - https://www.mdpi.com/1422-0067/22/3/1493 U6 - https://doi.org/10.3390/ijms22031493 VL - 22 IS - 3 ER - TY - GEN A1 - Geburek, Ina A1 - Rutz, Lukas A1 - Gao, Lan A1 - Küpper, Jan-Heiner A1 - These, Anja A1 - Schrenk, Dieter T1 - The metabolic pattern of hepatotoxic pyrrolizidine alkaloids in liver cells T2 - Chemical Research in Toxicology N2 - Contamination with 1,2-unsaturated pyrrolizidine alkaloids (PAs) is a serious problem for certain phytomedicines, foods, and animal feeds. Several of these PAs are genotoxic and carcinogenic, primarily in the liver, upon cytochrome P450 (CYP)-catalyzed activation into reactive (pyrrolic and pyrrole-like) metabolites. Here we investigated the metabolism of selected PAs (echimidine, europine, lasiocarpine, lycopsamine, retrorsine, and senecionine) in rat hepatocytes in primary culture and in human CYP3A4-transfected HepG2 cells. The open-chained diesters echimidine and lasiocarpine and the cyclic diester senecionine were extensively metabolized in rat hepatocytes into a broad spectrum of products released into the medium. A large portion of unidentified, possibly irreversibly bound, products remained in the cells while detectable amounts of reactive and other metabolites were found in the incubation media. In HepG2-CYP3A4 cells, lasiocarpine was more extensively metabolized than echimidine and senecionine which also gave rise to the release of pyrrolic metabolites. In human cells, no pyrrolic metabolites were detected in retrorsine or lycopsamine incubations, while no such metabolites were detected from europine in both cell types. Other types of metabolic changes comprised modifications such as side chain demethylation or oxygenation reactions like the formation of N-oxides. The latter, considered as a detoxification step, was a major pathway with cyclic diesters, was less distinctive for echimidine and lycopsamine and almost negligible for lasiocarpine and europine. Our data are in agreement with previously published cyto- and genotoxicity findings and suggests that the metabolic pattern may contribute substantially to the specific toxic potency of a certain congener. In addition, marked differences were found for certain congeners between rat hepatocytes and transfected human HepG2 cells, whereby a high level of bioactivation was found for lasiocarpine, whereas a very low level of bioactivation was observed for monoesters, in particular in human cells. Y1 - 2021 UR - https://pubs.acs.org/doi/abs/10.1021/acs.chemrestox.0c00507 U6 - https://doi.org/10.1021/acs.chemrestox.0c00507 VL - 34 IS - 4 SP - 1101 EP - 1113 ER - TY - GEN A1 - Jung, Conrad H. G. A1 - Waldeck, Peter A1 - Petrick, Ingolf A1 - Braune, Steffen A1 - Küpper, Jan-Heiner A1 - Jung, Friedrich T1 - Bioreactor for the cultivation of Arthrospira platensis under controlled conditions T2 - Journal of Cellular Biotechnology N2 - A vertical flat-type bioreactor consisting of transparent polyethylene (food safe) was constructed, which is characterized by a flexible design and allows the adjustment of a light path of 1 cm – 8.5 cm and a working volume of 1.5 l – 4 l. To characterize the performance of the bioreactor, cultivation experiments were performed with the cyanobacterium Arthrospira platensis (AP). The growth was assessed continuously by monitoring optical density and intermittently by measuring the dry weight of the AP biomass. An on-line measurement technique for estimating biomass production rate in a photosynthetic microalgae culture was developed. The oxygen produced by AP in the culture medium was flushed out sparging using a mixture of air and CO2 (1%). Factors which might influence the AP growth were monitored: pH, temperature, oxygen concentration and the filling level were corrected automatically to compensate evaporation losses. As an example, the huge influence of the light intensity on the AP growth was tested. The increase of the photon flux density of 15 to 1200μmol/(l · d) led to a 22-fold increase of the productivity and a 3.1-fold shorter doubling time. Using an online measurement technique - together with the control of the growth process via a wireless local area network (WLAN) router and virtual private network - allows monitoring the growth of Arthrospira platensis remotely. Y1 - 2021 UR - https://content.iospress.com/articles/journal-of-cellular-biotechnology/jcb210032 U6 - https://doi.org/10.3233/JCB-210032 VL - 7 IS - 1 SP - 35 EP - 40 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 - Braune, Steffen A1 - Küpper, Jan-Heiner A1 - Jung, Friedrich T1 - Effect of Prostanoids on Human Platelet Function: An Overview T2 - International Journal of Molecular Science N2 - Prostanoids are bioactive lipid mediators and take part in many physiological and pathophysiological processes in practically every organ, tissue and cell, including the vascular, renal, gastrointestinal and reproductive systems. In this review, we focus on their influence on platelets, which are key elements in thrombosis and hemostasis. The function of platelets is influenced by mediators in the blood and the vascular wall. Activated platelets aggregate and release bioactive substances, thereby activating further neighbored platelets, which finally can lead to the formation of thrombi. Prostanoids regulate the function of blood platelets by both activating or inhibiting and so are involved in hemostasis. Each prostanoid has a unique activity profile and, thus, a specific profile of action. This article reviews the effects of the following prostanoids: prostaglandin-D2 (PGD2), prostaglandin-E1, -E2 and E3 (PGE1, PGE2, PGE3), prostaglandin F2α (PGF2α), prostacyclin (PGI2) and thromboxane-A2 (TXA2) on platelet activation and aggregation via their respective receptors. Y1 - 2020 UR - https://www.mdpi.com/1422-0067/21/23/9020 U6 - https://doi.org/10.3390/ijms21239020 VL - 21 IS - 23 ER - TY - GEN A1 - Braune, Steffen A1 - Krüger-Genge, Anne A1 - Kammerer, Sarah A1 - Jung, Friedrich A1 - Küpper, Jan-Heiner T1 - Phycocyanin from Arthrospira platensis as Potential Anti-Cancer Drug: Review of In Vitro and In Vivo Studies T2 - Life Y1 - 2021 UR - https://www.mdpi.com/2075-1729/11/2/91 U6 - https://doi.org/10.3390/life11020091 VL - 11 IS - 2 SP - 91 ER -