@misc{KammererSokolowskiHackletal., author = {Kammerer, Sarah and Sokolowski, Armin Andreas and Hackl, Hubert and Platzer, Dieter and Jahn, Stephan Wenzel and El-Heliebi, Amin and Schwarzenbacher, Daniela and Stiegelbauer, Verena and Pichler, Martin and Rezania, Simin and Fiegl, Heidelinde and Peintinger, Florentia and Regitnig, Peter and H{\"o}fler, Gerald and Schreibmayer, Wolfgang and Bauernhofer, Thomas}, title = {KCNJ3 is a new independent prognostic marker for estrogen receptor positive breast cancer patients}, series = {OncoTarget : open access impact journal}, volume = {7}, journal = {OncoTarget : open access impact journal}, number = {51}, doi = {10.18632/oncotarget.13224}, pages = {84705 -- 84717}, abstract = {Numerous studies showed abnormal expression of ion channels in different cancer types. Amongst these, the potassium channel gene KCNJ3 (encoding for GIRK1 proteins) has been reported to be upregulated in tumors of patients with breast cancer and to correlate with positive lymph node status. We aimed to study KCNJ3 levels in different breast cancer subtypes using gene expression data from the TCGA, to validate our findings using RNA in situ hybridization in a validation cohort (GEO ID GSE17705), and to study the prognostic value of KCNJ3using survival analysis. In a total of > 1000 breast cancer patients of two independent data sets we showed a) that KCNJ3 expression is upregulated in tumor tissue compared to corresponding normal tissue (p < 0.001), b) that KCNJ3 expression is associated with estrogen receptor (ER) positive tumors (p < 0.001), but that KCNJ3 expression is variable within this group, and c) that ER positive patients with high KCNJ3 levels have worse overall (p < 0.05) and disease free survival probabilities (p < 0.01), whereby KCNJ3 is an independent prognostic factor (p <0.05). In conclusion, our data suggest that patients with ER positive breast cancer might be stratified into high risk and low risk groups based on the KCNJ3 levels in the tumor.}, language = {en} } @misc{VerbruggeAlAssarafetal., author = {Verbrugge, Sue Ellen and Al, Marjon and Assaraf, Yehuda G. and Kammerer, Sarah and Chandrupatla, Durga and Honeywell, Richard and Musters, Rene and Giovannetti, Elisa and O`Toole, Tom and Scheffer, George L. and Krige, David and Gruijl, Tanja de and Niessen, Hans W.M. and Lems, Willem F. and Kramer, Pieternella A. and Scheper, Rik J. and Cloos, Jacqueline and Ossenkoppele, Gert and Peters, Godefridus J. and Jansen, Gerrit}, title = {Multifactorial resistance to aminopeptidase inhibitor prodrug CHR2863 in myeloid leukemia cells: Down-regulation of carboxylesterase 1, drug sequestration in lipid droplets and pro-survival activation ERK/Akt/mTOR}, series = {OncoTarget : open access impact journal}, volume = {7}, journal = {OncoTarget : open access impact journal}, number = {5}, issn = {1949-2553}, doi = {10.18632/oncotarget.6169}, pages = {5240 -- 5257}, abstract = {Aminopeptidase inhibitors are receiving attention as combination chemotherapeutic agents for the treatment of refractory acute myeloid leukemia. However, the factors determining therapeutic efficacy remain elusive. Here we identified the molecular basis of acquired resistance to CHR2863, an orally available hydrophobic aminopeptidase inhibitor prodrug with an esterase-sensitive motif, in myeloid leukemia cells. CHR2863 enters cells by diffusion and is retained therein upon esterase activity-mediated conversion to its hydrophilic active metabolite drug CHR6768, thereby exerting amino acid depletion. Carboxylesterases (CES) serve as candidate prodrug activating enzymes given CES1 expression in acute myeloid leukemia specimens. We established two novel myeloid leukemia sublines U937/CHR2863(200) and U937/CHR2863(5uM), with low (14-fold) and high level (270-fold) CHR2863 resistance. The latter drug resistant cells displayed: (i) complete loss of CES1-mediated drug activation associated with down-regulation of CES1 mRNA and protein, (ii) marked retention/sequestration of the prodrug, (iii) a substantial increase in intracellular lipid droplets, and (iv) a dominant activation of the pro-survival Akt/mTOR pathway. Remarkably, the latter feature coincided with a gain of sensitivity to the mTOR inhibitor rapamycin. These finding delineate the molecular basis of CHR2863 resistance and offer a novel modality to overcome this drug resistance in myeloid leukemia cells.}, language = {en} } @misc{LiRezaniaKammereretal., author = {Li, Chouyang and Rezania, Simin and Kammerer, Sarah and Sokolowski, Armin Andreas and Devaney, Trevor Thomas Joseph and Gorischek, Astrid and Jahn, Stephan Wenzel and Hackl, Hubert and Groschner, Klaus and Windpassinger, Christian and Malle, Ernst and Bauernhofer, Thomas and Schreibmayer, Wolfgang}, title = {Piezo1 forms mechanosensitive ion channels in the human MCF-7 breast cancer cell line}, series = {Scientific Reports}, volume = {5}, journal = {Scientific Reports}, issn = {2045-2322}, doi = {10.1038/srep08364}, pages = {9}, abstract = {Mechanical interaction between cells - specifically distortion of tensional homeostasis-emerged as an important aspect of breast cancer genesis and progression. We investigated the biophysical characteristics of mechanosensitive ion channels (MSCs) in the malignant MCF-7 breast cancer cell line. MSCs turned out to be the most abundant ion channel species and could be activated by negative pressure at the outer side of the cell membrane in a saturable manner. Assessing single channel conductance (GΛ) for different monovalent cations revealed an increase in the succession: Li⁺ < Na⁺ < K⁺ ≈Rb⁺ ≈ Cs⁺. Divalent cations permeated also with the order: Ca²⁺ < Ba²⁺. Comparison of biophysical properties enabled us to identify MSCs in MCF-7 as ion channels formed by the Piezo1 protein. Using patch clamp technique no functional MSCs were observed in the benign MCF-10A mammary epithelial cell line. Blocking of MSCs by GsMTx-4 resulted in decreased motility of MCF-7, but not of MCF-10A cells, underscoring a possible role of Piezo1 in invasion and metastatic propagation. The role of Piezo1 in biology and progression of breast cancer is further substantiated by markedly reduced overall survival in patients with increased Piezo1 mRNA levels in the primary tumor.}, language = {en} } @misc{GuentherGrothSchieracketal., author = {Guenther, Sebastian and Groth, Ingrid and Schierack, Peter and Grabley, Susanne and Munder, Thomas}, title = {Direct detection of Kitasatospora species with a chaperone oligonucleotide microarray method lacking PCR amplification}, series = {Journal of basic microbiology}, volume = {48}, journal = {Journal of basic microbiology}, number = {4}, issn = {1521-4028}, doi = {10.1002/jobm.200800038}, pages = {315 -- 318}, language = {en} } @misc{KruegerGengeSteinbrechtKuepperetal., author = {Kr{\"u}ger-Genge, Anne and Steinbrecht, Susanne and K{\"u}pper, Jan-Heiner and Lendlein, Andreas and Jung, Friedrich}, title = {Evidence for cytostatic effect of cyclophosphamide on human vein endothelial cells in cancer therapy: preliminary in vitro results.}, series = {Clinical Hemorheology and Microcirculation}, volume = {69}, journal = {Clinical Hemorheology and Microcirculation}, number = {1-2}, issn = {1875-8622}, doi = {10.3233/CH-189125}, pages = {267 -- 276}, language = {en} } @misc{KammererKuepper, author = {Kammerer, Sarah and K{\"u}pper, Jan-Heiner}, title = {Human Hepatocyte Systems for in vitro Toxicology Analysis.}, series = {Journal of Cellular Biotechnology}, volume = {3}, journal = {Journal of Cellular Biotechnology}, number = {2}, issn = {2352-3697}, doi = {10.3233/JCB-179012}, pages = {85 -- 93}, language = {en} } @misc{KammererKuepper, author = {Kammerer, Sarah and K{\"u}pper, Jan-Heiner}, title = {Optimized protocol for induction of cytochrome P450 enzymes 1A2 and 3A4 in human primary-like hepatocyte cell strain HepaFH3 to study in vitro toxicology}, series = {Clinical Hemorheology and Microcirculation}, volume = {70}, journal = {Clinical Hemorheology and Microcirculation}, number = {4}, issn = {1386-0291}, doi = {10.3233/CH-189321}, pages = {563 -- 571}, language = {en} } @misc{SteinbrechtKoenigSchmidtkeetal., author = {Steinbrecht, Susanne and K{\"o}nig, Rosalie and Schmidtke, Kai-Uwe and Herzog, Natalie and Scheibner, Katrin and Kr{\"u}ger-Genge, Anne and Jung, Friedrich and Kammerer, Sarah and K{\"u}pper, Jan-Heiner}, title = {Metabolic activity testing can underestimate acute drug cytotoxicity as revealed by HepG2 cell clones overexpressing cytochrome P450 2C19 and 3A4}, series = {Toxicology}, volume = {412}, journal = {Toxicology}, issn = {0300-483X}, doi = {10.1016/j.tox.2018.11.008}, pages = {37 -- 47}, language = {en} } @misc{KruegerGengeBrauneWalteretal., author = {Kr{\"u}ger-Genge, Anne and Braune, Steffen and Walter, Maria and Kratz, Karl and K{\"u}pper, Jan-Heiner and Krengel, M. and Lendlein, Andreas and Jung, Friedrich}, title = {Influence of surface treatments of poly(n-butyl acrylate) networks on fibroblasts adhesion, morphology and viability}, series = {Clinical Hemorheology and Microcirculation}, volume = {69}, journal = {Clinical Hemorheology and Microcirculation}, number = {1-2}, issn = {1875-8622}, doi = {10.3233/CH-189130}, pages = {305 -- 316}, language = {en} } @misc{NowakKammererKuepper, author = {Nowak, Elisabeth and Kammerer, Sarah and K{\"u}pper, Jan-Heiner}, title = {ATP-based cell viability assay is superior to trypan blue exclusion and XTT assay in measuring cytotoxicity of anticancer drugs Taxol and Imatinib, and proteasome inhibitor MG-132 on human hepatoma cell line HepG2.}, series = {Clinical Hemorheology and Microcirculation}, volume = {69}, journal = {Clinical Hemorheology and Microcirculation}, number = {1-2}, issn = {1386-0291}, doi = {10.3233/CH-189120}, pages = {327 -- 336}, language = {en} } @misc{NiesProftNehringetal., author = {Nies, A. and Proft, L. and Nehring, M. E. and Gruber, Cnristian and Sievers, H. and H{\"u}nigen, Hana and Rodruigues, A. G. and Gemeinhardt, Ole and Mrowietz, Christof and Jung, Friedrich and Hiebl, Bernhard}, title = {Growth-related micromorphological characteristics of the porcine femoral artery}, series = {Clinical Hemorheology and Microcirculation}, volume = {73}, journal = {Clinical Hemorheology and Microcirculation}, number = {1}, issn = {1875-8622}, doi = {10.3233/CH-199219}, pages = {195 -- 201}, language = {en} } @misc{GerkFrankeJungetal., author = {Gerk, U. and Franke, Ralf-Peter and Jung, Ernst Michael and Scheller, B. and Kr{\"u}ger-Genge, Anne and Jung, Friedrich}, title = {Imaging of coronary arteries using ionic versus non-ionic radiographic contrast media: Intraindividual comparison study}, series = {Clinical Hemorheology and Microcirculation}, journal = {Clinical Hemorheology and Microcirculation}, issn = {1875-8622}, doi = {10.3233/CH-199217}, pages = {8}, language = {en} } @misc{ParkMatschkeMrowietzetal., author = {Park, J. W. and Matschke, K. and Mrowietz, Christof and Kr{\"u}ger-Genge, Anne and Jung, Friedrich}, title = {HELP-(Heparin-induced Extracorporeal LDL Precipitation)-apheresis in heart recipients with cardiac allograft vasculopathy and concomitant hypercholesterolemia: Influence of long-term treatment on the microcirculation}, series = {Clinical Hemorheology and Microcirculation}, volume = {73}, journal = {Clinical Hemorheology and Microcirculation}, number = {1}, issn = {1875-8622}, doi = {10.3233/CH-199216}, pages = {19 -- 27}, language = {en} } @misc{HofmanSorfVagiannisetal., author = {Hofman, Jakub and Sorf, Ales and Vagiannis, Dimitrios and Sucha, Simona and Novotna, Eva and Kammerer, Sarah and K{\"u}pper, Jan-Heiner and Ceckova, Martina and Staud, Frantisek}, title = {Interactions of Alectinib with Human ATP-Binding Cassette Drug Efflux Transporters and Cytochrome P450 Biotransformation Enzymes: Effect on Pharmacokinetic Multidrug Resistance}, series = {Drug Metabolism and Disposition}, volume = {47}, journal = {Drug Metabolism and Disposition}, number = {7}, issn = {1521-009X}, doi = {10.1124/dmd.119.086975}, pages = {699 -- 709}, language = {en} } @misc{SteinbrechtKammererKuepper, author = {Steinbrecht, Susanne and Kammerer, Sarah and K{\"u}pper, Jan-Heiner}, title = {HepG2 cells with recombinant cytochrome P450 enzyme overexpression: Their use and limitation as in vitro liver model}, series = {Journal of Cellular Biotechnology}, volume = {5}, journal = {Journal of Cellular Biotechnology}, number = {1}, issn = {2352-3697}, doi = {10.3233/JCB-189013}, pages = {55 -- 64}, language = {en} } @misc{HofmanSorfVagiannisetal., author = {Hofman, Jakub and Sorf, Ales and Vagiannis, Dimitrios and Sucha, Simona and Kammerer, Sarah and K{\"u}pper, Jan-Heiner and Chen, Si and Guo, Lei and Ceckova, Martina and Staud, Frantisek}, title = {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}, series = {Molecular Pharmaceutics}, volume = {16}, journal = {Molecular Pharmaceutics}, number = {11}, doi = {10.1021/acs.molpharmaceut.9b00361}, pages = {4436 -- 4450}, language = {en} } @misc{HailekaGeorgeSteinbrechtetal., author = {Haileka, Vanessa and George, Sandra and Steinbrecht, Susanne and Jung, Friedrich and Reinehr, R. and K{\"u}pper, Jan-Heiner}, title = {Colon cancer cells cultured under hyperosmotic conditions as in vitro model to investigate dehydration effects on cancer drug susceptibility}, series = {Clinical Hemorheology and Microcirculation}, volume = {73}, journal = {Clinical Hemorheology and Microcirculation}, number = {1}, issn = {1875-8622}, doi = {10.3233/CH-199210}, pages = {169 -- 176}, language = {en} } @misc{SchulzKammererKuepper, author = {Schulz, Christian and Kammerer, Sarah and K{\"u}pper, Jan-Heiner}, title = {NADPH-cytochrome P450 reductase expression and enzymatic activity in primary-like human hepatocytes and HepG2 cells for in vitro biotransformation studies}, series = {Clinical Hemorheology and Microcirculation}, volume = {73}, journal = {Clinical Hemorheology and Microcirculation}, number = {1}, issn = {1386-0291}, doi = {10.3233/CH-199226}, pages = {249 -- 260}, language = {en} } @misc{UhligGehreKammereretal., author = {Uhlig, Katja and Gehre, Christian P. and Kammerer, Sarah and K{\"u}pper, Jan-Heiner and Coleman, D. and P{\"u}schel, G. and Duschl, Claus}, title = {Real-time monitoring of oxygen consumption of hepatocytes in a microbioreactor}, series = {Toxicology Letters}, volume = {295}, journal = {Toxicology Letters}, number = {Supplement 1}, issn = {0378-4274}, doi = {10.1016/j.toxlet.2018.06.652}, pages = {S115}, language = {en} } @misc{KruegerGengeBlockiFrankeetal., author = {Kr{\"u}ger-Genge, Anne and Blocki, Anna and Franke, Ralf-Peter and Jung, Friedrich}, title = {Vascular Endothelial Cell Biology: An Update}, series = {International Journal of Molecular Sciences}, volume = {20}, journal = {International Journal of Molecular Sciences}, number = {18}, issn = {1422-0067}, doi = {10.3390/ijms20184411}, pages = {22}, language = {en} } @misc{SteinbrechtPfeiferHerzogetal., author = {Steinbrecht, Susanne and Pfeifer, Nadine and Herzog, Natalie and Katzenberger, Nadine and Schulz, Christian and Kammerer, Sarah and K{\"u}pper, Jan-Heiner}, title = {HepG2-1A2 C2 and C7: Lentivirus vector-mediated stable and functional overexpression of cytochrome P450 1A2 in human hepatoblastoma cells}, series = {Toxicology Letters}, volume = {319}, journal = {Toxicology Letters}, issn = {0378-4274}, doi = {10.1016/j.toxlet.2019.11.006}, pages = {155 -- 159}, abstract = {Novel HepG2 cell clones 1A2 C2 and 1A2 C7 were independently generated by lentiviral transduction to functionally overexpress cytochrome P450 1A2 (CYP1A2). We found similar and stable CYP1A2 transcript and protein levels in both cell clones leading to specific enzyme activities of about 370 pmol paracetamol x min-1 x mg-1 protein analyzed by phenacetin conversion. Both clones showed dramatically increased sensitivity to the hepatotoxic compound aflatoxin B1 (EC50<100 nM) when compared to parental HepG2 cells (EC50 ∼5 μM). Thus, newly established cell lines are an appropriate tool to study metabolism and toxicity of substances depending on conversion by CYP1A2.}, language = {en} } @misc{JungConnesLehmann, author = {Jung, Friedrich and Connes, Philippe and Lehmann, Christian}, title = {A.L. Copley Best Paper Prize 2018}, series = {Clinical Hemorheology and Microcirculation}, volume = {72}, journal = {Clinical Hemorheology and Microcirculation}, number = {2}, issn = {1386-0291}, doi = {10.3233/CH-199008}, pages = {117 -- 118}, language = {en} } @misc{LauRangarajanKruegerGengeetal., author = {Lau, S. and Rangarajan, R. and Kr{\"u}ger-Genge, Anne and Braune, Steffen and Kammerer, Sarah and K{\"u}pper, Jan-Heiner and Lendlein, Andreas and Jung, Friedrich}, title = {Effects of acrolein in comparison to its prodrug cyclophosphamide on human primary endothelial cells in vitro}, series = {Toxicology in Vitro}, volume = {62}, journal = {Toxicology in Vitro}, issn = {0887-2333}, doi = {10.1016/j.tiv.2019.104685}, pages = {8}, abstract = {Cyclophosphamide (CPA) is one of the most successful anticancer prodrugs that becomes effective after biotransformation in the liver resulting in the toxic metabolite acrolein. Cancer is often accompanied by thromboembolic events, which might be a result of dysfunctional endothelial cells due to CPA treatment. Here, the effect of 1 mM CPA or acrolein (10/50/100/500 μM) on human umbilical vein endothelial cells (HUVECs) was analyzed after two days of treatment. The addition of CPA or 10 μM acrolein did not affect HUVECs. However, concentrations of 100 μM and 500 μM acrolein significantly reduced the number of adherent cells by 86 ± 13\% and 99 ± 1\% and cell viability by 51 ± 29\% and 93 ± 8\% compared to the control. Moreover, pronounced stress fibers as well as multiple nuclei were observed and von Willebrand factor (vWF) was completely released. Lactate dehydrogenase was 8.5 ± 7.0-fold and 252.9 ± 42.9-fold increased showing a loss of cell membrane integrity. The prostacyclin and thromboxane secretion was significantly increased by the addition of 500 μM acrolein (43.1 ± 17.6-fold and 246.4 ± 106.3-fold) indicating cell activation/pertubation. High doses of acrolein led to HUVEC death and loss of vWF production. This effect might be associated with the increased incidence of thromboembolic events in cancer patients treated with high doses of CPA.}, language = {en} } @misc{JungKruegerGengeWaldecketal., author = {Jung, Friedrich and Kr{\"u}ger-Genge, Anne and Waldeck, Peter and K{\"u}pper, Jan-Heiner}, title = {Spirulina platensis, a super food?}, series = {Journal of Cellular Biotechnology}, volume = {5}, journal = {Journal of Cellular Biotechnology}, number = {1}, issn = {2352-3689}, doi = {10.3233/JCB-189012}, pages = {43 -- 54}, abstract = {Spirulina platensis, a multicelluar, photosynthetic prokaryote (algae) contains a high amount of proteins, vitamins and minerals superior to many foods as e.g. soybeans. Thus, Spirulina platensis was recognized as nutritious food by the United Nations World Food Conference. Due to the high amount of nutritive ingredients Spirulina has a long history as dietary supplement. In addition, spirulina platensis is also efficiently used as forage with known effects on flesh, egg and plumage color, milk yield and fertility. The versatile utilization of the alga can be explained on the one hand with the nutrient levels and on the other hand with recognized effects as anti-viral, anti-bacterial, anti-oxidant, anti-diabetic, anti-cancer and anti-inflammatory substance. Therefore, this alga is named as "superfood". Beyond, these algae convert carbon dioxide into organic substances and produce oxygen during their growth in alkaline and saline water thereby not wasting fresh water allowing the production in barren areas. Despite this diverse use of Spirulina platensis due to its beneficial properties, many basic mechanisms on a molecular and cellular level are not well understood and should be explored in future studies.}, language = {en} } @misc{KruegerGengeJungKuepperetal., author = {Kr{\"u}ger-Genge, Anne and Jung, Friedrich and K{\"u}pper, Jan-Heiner and Lehmann, Christian and Franke, Ralf-Peter}, title = {Actin type and distribution in erythrocytes}, series = {Journal of Cellular Biotechnology}, volume = {3}, journal = {Journal of Cellular Biotechnology}, number = {2}, issn = {2352-3697}, doi = {10.3233/JCB-179014}, pages = {81 -- 83}, abstract = {Erythrocytes transport oxygen from the lungs to the tissues. The excess surface area together with the elasticity of the erythrocyte cell membrane provides the flexibility needed to pass through the microvasculature where the oxygen exchange occurs. Although the architecture of the red cell and its membrane-associated cytoskeletal network is known in general, the factors that control the characteristic shape change during echinocyte formation are poorly understood. In this short report we show that in echinocytes a completely reorganized membrane cytoskeleton with a box-like structure of actin filaments prevailed indicating the importance of the actin cytoskeleton during echinocyte formation.}, language = {en} } @misc{JungJungKruegerGengeetal., author = {Jung, Friedrich and Jung, Conrad H. G. and Kr{\"u}ger-Genge, Anne and Waldeck, Peter and K{\"u}pper, Jan-Heiner}, title = {Factors influencing the growth of Spirulina platensis in closed photobioreactors under CO₂ - O₂ conversion}, series = {Journal of Cellular Biotechnology}, volume = {5}, journal = {Journal of Cellular Biotechnology}, number = {2}, issn = {2352-3697}, doi = {10.3233/JCB-199004}, pages = {125 -- 134}, abstract = {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.}, language = {en} } @misc{LeeGanesanKruegerGengeetal., author = {Lee, Seahyoung and Ganesan, Ramakrishnan and Kr{\"u}ger-Genge, Anne and Kratz, Karl and Franke, Ralf-Peter and Lendlein, Andreas and Jung, Friedrich}, title = {Substrate-enzyme affinity-based surface modification strategy for endothelial cell-specific binding under shear stress}, series = {Clinical Hemorheology and Microcirculation}, volume = {75}, journal = {Clinical Hemorheology and Microcirculation}, number = {1}, issn = {1875-8622}, doi = {10.3233/CH-190736}, pages = {85 -- 98}, abstract = {Establishing an endothelial cell (EC) monolayer on top of the blood contacting surface of grafts is considered to be a promising approach for creating a hemocompatible surface. Here we utilized the high affinity interactions between the EC plasma membrane expressed enzyme called endothelin converting enzyme-1 (ECE-1) and its corresponding substrate big Endothelin-1 (bigET-1) to engineer an EC-specific binding surface. Since enzymatic cleavage of substrates require physical interaction between the enzyme and its corresponding substrate, it was hypothesized that a surface with chemically immobilized synthetic bigET-1 will preferentially attract ECs over other types of cells found in vascular system such as vascular smooth muscle cells (VSMCs). First, the expression of ECE-1 was significantly higher in ECs, and ECs processed synthetic bigET-1 to produce ET-1 in a cell number-dependent manner. Such interaction between ECs and synthetic bigET-1 was also detectible in blood. Next, vinyl-terminated self-assembled monolayers (SAMs) were established, oxidized and activated on a glass substrate as a model to immobilize synthetic bigET-1 via amide bonds. The ECs cultured on the synthetic bigET-1-immobilized surface processed larger amount of synthetic bigET-1 to produce ET-1 compared to VSMCs (102.9±5.13 vs. 9.75±0.74 pg/ml). The number of ECs bound to the synthetic bigET-1-immobilized surface during 1 h of shearing (5dyne/cm2) was approximately 3-fold higher than that of VSMCs (46.25±12.61 vs. 15.25±3.69 cells/100×HPF). EC-specific binding of synthetic bigET-1-immobilized surface over a surface modified with collagen, a common substance for cell adhesion, was also observed. The present study demonstrated that using the substrate-enzyme affinity (SEA) of cell type-specific enzyme and its corresponding substrate can be an effective method to engineer a surface preferentially binds specific type of cells. This novel strategy might open a new route toward rapid endothelialization under dynamic conditions supporting the long-term patency of cardiovascular implants.}, language = {en} } @misc{JungPietzsch, author = {Jung, Friedrich and Pietzsch, Jens}, title = {Regulation of bone regeneration}, series = {Clinical Hemorheology and Microcirculation}, volume = {73}, journal = {Clinical Hemorheology and Microcirculation}, number = {3}, issn = {1875-8622}, doi = {10.3233/CH-199101}, pages = {379 -- 380}, language = {en} } @misc{Jung, author = {Jung, Friedrich}, title = {COVID-19}, series = {Clinical Hemorheology and Microcirculation}, volume = {74}, journal = {Clinical Hemorheology and Microcirculation}, number = {4}, issn = {1875-8622}, doi = {10.3233/CH-209001}, pages = {347 -- 348}, abstract = {The pandemic of coronavirus disease 2019 (COVID-19), a disease caused by a novel coronavirus (CoV), SARS-CoV-2, is causing substantial morbidity and mortality. The etiology of this illness is now attributed to a novel virus belonging to the coronavirus (CoV) family. An epidemic of cases with respiratory infections detected in Wuhan, China, was first reported to the WHO Country Office in China, on December 31, 2019. This new virus seems to be very contagious and has quickly spread globally. The estimate for severe cases was approximated at 5\% based on experience from China. However, the World Health Organization's (WHO) estimate from China for severe and critical cases is near 20\% [2]. Older age seems to be the highest risk for death. Mortality data from Oxford COVID-19 Evidence Service (25/3/20) indicates a risk of mortality of 3.6\% for people in their 60 s, which increases to 8.0\% for people older than 70 and to 14.8\% for people over 80 s [3]. In addition, a very recent epidemiological study could show that already a small increase in long-term exposure to fine particular matter leads to a 20-times increase in COVID-19 death rate [4], showing that it is not only age and previous illnesses that predispose, but also the environmental conditions. In addition to respiratory disease, cardiovascular complications are reported to be a key threat in COVID-19 [5, 6]. In a second Editorial, F. Wenzel exposes this pandemic from a historical and socio-political perspective in a very interesting article [7]. In a feature about the European - Asian perspective Jung et al. present the development of COVID-19 in Germany and show a way to predict the time point at which no further new infections will occur using Normalized Case Number Curves (plateau day) [8]. 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. First experiences with abdominal contrast-enhanced ultrasound (CEUS) examinations are presented by the group of E.M. Jung [6]. In the stage of an imminent organ failure with significantly reduced kidney and liver function and microcirculation, CEUS can be used to show a narrowing of the organ-supplying arteries, as well as a delayed capillary filling of vessels near the capsule, a regional reduced parenchymal perfusion or an inflammatory hyperemia with capillary hypercirculation.}, language = {en} } @misc{JungStroszczynskiJung, author = {Jung, Ernst Michael and Stroszczynski, Christian and Jung, Friedrich}, title = {Contrast enhanced ultrasonography (CEUS) to detect abdominal microcirculatory disorders in severe cases of COVID-19 infection: First experience}, series = {Clinical Hemorheology and Microcirculation}, volume = {74}, journal = {Clinical Hemorheology and Microcirculation}, number = {4}, issn = {1875-8622}, doi = {10.3233/CH-209003}, pages = {353 -- 361}, abstract = {In the hands of experienced examiners, the contrast enhanced sonography (CEUS) offers the possibility to analyze dynamic microcirculatory disturbances in real time dynamically without any risk for kidneys and thyroid gland even in severe progressing disease bedside. Based on severe COVID-19 infections, first experiences with abdominal CEUS examinations are presented. In the stage of an imminent organ failure with significantly reduced kidney and liver function, CEUS can be used to show a narrowing of the organ-supplying arteries, as well as a delayed capillary filling of vessels near the capsule, a regional reduced parenchymal perfusion or an inflammatory hyperemia with capillary hypercirculation. It is possible to quickly rule out organ infarction and to dynamically record the mesenteric arterial and venous blood flow.}, language = {en} } @misc{JungStroszczynskiJung, author = {Jung, Ernst Michael and Stroszczynski, Christian and Jung, Friedrich}, title = {Contrast enhanced ultrasound (CEUS) to assess pleural pulmonal changes in severe Covid 19 infection: First results}, series = {Clinical Hemorheology and Microcirculation}, volume = {75}, journal = {Clinical Hemorheology and Microcirculation}, number = {1}, issn = {1875-8622}, doi = {10.3233/CH-209005}, pages = {19 -- 26}, abstract = {AIM: Use of contrast enhanced ultrasound (CEUS) in severe cases of COVID-19 infection to assess pulmonary changes near the pleura. MATERIAL AND METHODS: Bedside examinations by an experienced intensive care unit examiner using a multi-frequency probe (C1-6 MHz) with B-mode and CEUS to assess pleural-near changes in severe cases of COVID-19 infection with respiratory failure. CEUS with bolus delivery via a central venous catheter of 2.4 ml Sulphur hexafluoride microbubbles from the arterial phase (10-15 s) to the late phase of 5 min. Digital storage of cine sequences of the lung sound with abdomen for independent assessment with the subsequently performed contrast-enhanced dual-source CT. RESULTS: In 11 intubated and ventilated patients (arithmetic mean 62 years, 48 to 78 years, 3 women) with confirmed severe COVID-19 infections, a peripherally accentuated consolidation with irregular hyperemia was found in the CEUS and also in the CT examination. Of the 5 cases with pulmonary arterial embolisms, signs of right ventricular failure were found. In all cases, using CEUS low perfused areas of the pleura with adjacent hyperemia could be detected, while, with CT segmental contrast medium, gaps with subpleural compressions were found. Interstitial changes near the pleura led to B-lines and to ground glass opacities in the CT. Near the diaphragm a delayed arterial contrast of the liver was observed. In addition, in 2 cases partial atelectasis, in 3 cases marginal pleural effusions were found. CONCLUSION: CEUS opens up new possibilities for bedside monitoring of pleural reactive inflammatory or peripheral thrombus embolism in severe cases of COVID-19 infection.}, language = {en} } @misc{JungConnesLehmann, author = {Jung, Friedrich and Connes, Philippe and Lehmann, Christian}, title = {A.L. Copley Best Paper Prize 2019}, series = {Clinical Hemorheology and Microcirculation}, volume = {75}, journal = {Clinical Hemorheology and Microcirculation}, number = {1}, issn = {1875-8622}, doi = {10.3233/ch-209100}, pages = {1 -- 2}, language = {en} } @misc{LambyMinkowHandtetal., author = {Lamby, Philipp and Minkow, Alexander and Handt, Stefan and Falter, Johannes and Schellenberg, Eva-Lotte and Graf, Stefanie and Hiebl, Bernhard and Haerteis, Silke and Gemeinhardt, Ole and Kr{\"u}ger-Genge, Anne and Klosterhalfen, Bernd and Jung, Ernst Michael and Franke, Ralf-Peter and Momeni, Arash and Prantl, Lukas and Jung, Friedrich}, title = {Histological and SEM assessment of blood stasis in kidney blood vessels after repeated intra-arterial application of radiographic contrast media}, series = {Life}, volume = {10}, journal = {Life}, number = {9}, issn = {2075-1729}, doi = {10.3390/life10090167}, pages = {16}, abstract = {Background: After application of iodinated contrast media (CM), a pronounced deterioration of the microcirculation in skin and myocardium was reported. Clinically, the repeated application of CM, especially, led to an increase of the renal resistance index (RRI). With respect to the transiency of the RRI increase, it is reasonable to assume that the deterioration of blood flow could be due to transient blood stasis caused by reversible morphologic cell alterations due to osmotic discrepancies between CM and human blood. Therefore, the hypothesis was investigated whether CM are able to induce in vivo such blood stasis and cell deformations in the renal vasculature of well-hydrated pigs. Methods: The in vivo study was performed as a prospective randomized examination to compare the effects of two different CM in 16 pigs (German Landrace). Pigs were randomized to receive either Iodixanol (n = 8), or Iopromide (n = 8). Each animal received 10 injections separated by 5-min intervals via the suprarenal aorta at a rate of 10 mL/s according to the usual procedure during a cardiac catheter examination. Finally, the kidneys were explanted and processed for histology (H \& E staining and fibrin staining according to Weigert) as well as for scanning electron microscopy (SEM) with regards to morphologic correlates explaining the changes in the microcirculation. Results: In each of the predefined four categories of vascular diameters, blood stasis were found, but clearly more often after application of Iopromide than after application of Iodixanol (p < 0.001). In addition, Iopromide induced more blood stasis in all of the examined kidney regions compared to Iodixanol (p = 0.0001). There were no obstructive events in the middle cortex following the application of Iodixanol. Except for the region around a puncture channel of a placed-in catheter probe, no fibrin was detected in Weigert's fibrin-stained samples, neither around the histologically assessed thrombi nor in vessels with blood stasis. Complementary SEM analyses revealed in a few cases only a slight generation of fibrin and thrombi and deformations, such as echinocyte and "box-like" deformations. Conclusions: According to previous in vitro studies, pathological erythrocyte deformations, such as echinocyte and box-like formation of erythrocytes, were observed also in vivo. In addition, blood stasis and/or thrombi could be detected in histological samples from explanted kidneys from young pigs after repeated in vivo administration of CM. In only a few cases, mural platelet aggregates within minimal fibrin meshes occurred only after the application of Iopromide.}, language = {en} } @misc{KruegerGengeJungHufertetal., author = {Kr{\"u}ger-Genge, Anne and Jung, Friedrich and Hufert, Frank and Jung, Ernst Michael and K{\"u}pper, Jan-Heiner and Storsberg, J.}, title = {Effects of gut microbial metabolite trimethylamine N-oxide (TMAO) on platelets and endothelial cells}, series = {Clinical Hemorheology and Microcirculation}, volume = {76}, journal = {Clinical Hemorheology and Microcirculation}, number = {2}, issn = {1875-8622}, doi = {10.3233/CH-209206}, pages = {309 -- 316}, abstract = {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.}, language = {en} } @misc{MrowietzSieversPinduretal., author = {Mrowietz, Christof and Sievers, H. and Pindur, Gerhard and Hiebl, Bernhard and Jung, Friedrich}, title = {Cutaneous microcirculation in patients with peripheral arterial occlusive disease: Comparison of capillary blood circulation in the nail fold of finger and toe}, series = {Clinical Hemorheology and Microcirculation}, volume = {76}, journal = {Clinical Hemorheology and Microcirculation}, number = {2}, issn = {1875-8622}, doi = {10.3233/CH-209220}, pages = {279 -- 285}, abstract = {In patients with peripheral arterial occlusive disease (PAOD) a restricted circulation in cutaneous microvessels has been reported. In this study the velocity of erythrocytes (very) in finger nailfold capillaries - a vascular area without upstream macroangiopathy - and also in toe nailfold capillaries - a post-stenotic area -was investigated using capillary microscopy in apparently healthy subjects and patients with PAOD. Already in finger nailfold capillaries very of patients with PAOD under resting conditions was significantly lower than in capillaries of healthy subjects. This was also true for the circulation in toe capillaries. In addition, the erythrocyte velocities under resting conditions in the toe capillaries were significantly lower than in the finger capillaries. Similar results were found for the duration and the maximum velocity of postocclusive hyperemia. It is concluded that the resting blood flow in the skin microcirculation is impaired in PAOD patients, both under resting conditions and during postocclusive hyperemia in finger as well in toe nailfold capillaries.}, language = {en} } @misc{MartinaKammererPrantletal., author = {Martina, Georgieva and Kammerer, Sarah and Prantl, Lukas and Jung, Friedrich and Stroszczynski, Christian and Jung, Ernst Michael}, title = {Imaging of breast implant and implant-associated complications: Capsular contracture and intraor extracapsular rupture}, series = {Clinical Hemorheology and Microcirculation}, volume = {76}, journal = {Clinical Hemorheology and Microcirculation}, number = {2}, issn = {1875-8622}, doi = {10.3233/CH-209218}, pages = {221 -- 231}, abstract = {BACKGROUND: In recent years, follow-up after breast reconstruction with silicone implants and the detection of complications have been relieved by the possibility of improved diagnostic methods. METHODS: Between January 2015 and December 2019 a total of 40 patients (29-84 years) with silicone implants were included in this retrospective study. The implants were examined clinically and with modern imaging: general ultrasound imaging (US), magnetic resonance imaging (MRI), high resolution computed tomography (CT) and positron emission tomography -computed tomography (PET-CT). If necessary, a histological/cytological sample was taken. The breast implants were assessed by three radiologists specialized in breast imaging. The grade of capsular contracture was classified according to the Baker classification. RESULTS: All 40 women obtained a clinical examination and an US diagnostic to identify early and more common complications such as implant folding and capsular fibrosis. Depending on the clinical examination and ultrasound findings additional MRI (n = 10), CT (n = 9) and/or PET-CT (n = 2) were performed. 16 patients had implants folding proven with US (n = 16), MRI (n = 6) and CT (n = 1). The grade of capsular fibrosis was determined according to the Baker classification. The following results were obtained in our study: 25 breast implants with Baker grade I and eleven breast implants with Baker grade II, both proven with US; one breast implants with Baker grade III and one breast implant with Baker grade IV, proven with US (n = 2), MRI (n = 1) and CT (n = 1). One patient had intracapsular rupture and one patient had extracapsular rupture, both detected on CT and surgically proven. No patient had a silicone accumulation in the lymph nodes. One patient had pathologically enlarged axillary lymph nodes, which were evaluated as inflammatory changes in PET-CT. Long-term complications such as the development of malignant breast tumors could not be observed. CONCLUSION: To detect early complications after breast implant surgery, a regular clinical examination is indispensable. Imaging methods complement each other and if they are used multimodal, it is easier to identify early complications. Modern diagnostic modalities like ultrasound and magnetic resonance imaging expand the spectrum and improve diagnostic safety.}, language = {en} } @misc{JungWertheimerPutzetal., author = {Jung, Ernst Michael and Wertheimer, T. and Putz, F. J. and Jung, Friedrich and Kammerer, Sarah and Pregler, B. and Luerken, L. and Stroszczynski, Christian and Beyer, L.}, title = {Contrast enhanced ultrasound (CEUS) with parametric imaging and time intensity curve analysis (TIC) for evaluation of the success of prostate arterial embolization (PAE) in cases of prostate hyperplasia}, series = {Clinical Hemorheology and Microcirculation}, volume = {76}, journal = {Clinical Hemorheology and Microcirculation}, number = {2}, issn = {1875-8622}, doi = {10.3233/CH-209202}, pages = {143 -- 153}, abstract = {AIM: To evaluate the use of dynamic contrast enhanced ultrasound (CEUS) with parametric color-coded imaging and time intensity curve analysis (TIC) for planning and follow-up after prostate arterial embolization (PAE). MATERIAL/METHOD: Before and after selective iliacal embolization by PAE with a follow up of 6 months 18 male patients (43-78 years, mean 63±3.5 years) with histopathological proven benign prostate hyperplasia were examined by one experienced examiner. A multifrequency high resolution probe (1-6 MHz) was used for transabdominal ultrasound and CEUS with bolus injections of 2.4 ml sulphur-hexafluoride microbubbles. Independent evaluation of color-coded parametric imaging before and after PAE by in PACS stored DICOM loops from arterial phase (10-15 s) up to 1min were performed. Criteria for successful treatment were reduction of early arterial enhancement by changes of time to peak (TTP) and area under the curve (AUC) by measurements in 8 regions of interest (ROI) of 5 mm in diameter at the margin and in the center and changes from hyperenhancement in parametric imaging (perfusion evaluation of arterial enhancement over 15 s) from red and yellow to blue and green by partial infarctions. Reference imaging method was the contrast high resolution 3 tesla magnetic resonance tomography (MRI) using 3D vibe sequences before and after PAE and for the follow up after 3 and 6 months. RESULTS: PAE was technically and clinically successful in all 18 patients with less clinical symptoms and reduction of the gland volume. In all cases color-coded CEUS parametric imaging was able to evaluate partial infarction after embolization with changes from red and yellow to green and blue colors in the embolization areas. Relevant changes could be evaluated for TIC-analysis of CEUS with reduced arterial enhancement in the arterial phase and prolonged enhancement of up to 1 min with significant changes (p = 0.0024). The area under the curve (AUC) decreased from 676±255.04 rU (160 rU-1049 rU) before PAE to 370.43±255.19 rU (45 rU-858 rU) after PAE. Time to peak (TTP) did not change significantly (p = 0.6877); TTP before PAE was 25.82±9.04 s (12.3 s-42.5 s) and after PAE 24.43±9.10 s (12-39 s). Prostate volume decreased significantly (p = 0.0045) from 86.93±34.98 ml (30-139 ml) before PAE to 50.57±26.26 ml (19-117 ml) after PAE. There were no major complications and, in most cases (14/18) a volume reduction of the benign prostate hyperplasia occurred. CONCLUSION: Performed by an experienced examiner CEUS with parametric imaging and TIC-analysis is highly useful to further establish prostatic artery embolization (PAE) as a successful minimal invasive treatment of benign prostatic hyperplasia.}, language = {en} } @misc{GehmertLehoczkyLoibletal., author = {Gehmert, Sangaa and Lehoczky, Gy{\"o}z{\"o}c and Loibl, Markus and Jung, Friedrich and Prantl, Lukas and Gehmert, Sebastian}, title = {Interaction between extracellular cancer matrix and stromal breast cells}, series = {Clinical Hemorheology and Microcirculation}, volume = {74}, journal = {Clinical Hemorheology and Microcirculation}, number = {1}, issn = {1875-8622}, doi = {10.3233/CH-199234}, pages = {45 -- 52}, abstract = {Stromal-epithelial interactions are fundamental for normal organ development and there is a multitude of evidence that the different components of the microenvironment are also necessary for the maintenance and promotion of the "tumor organ". Deregulated tumor associated extracellular matrix (tECM) is a hallmark of cancer, causing an alteration in the amount and composition of the different components (i.e. proteins, proteoglycans, glycoproteins and polysaccharids) of the ECM. As epithelial-stromal interactions are reciprocal, it is possible that tECM itself is able to initiate tumor development. We therefore established a mouse model to examine the influence of tECM of murine breast cancer on developing breast tissue in mice.}, language = {en} } @misc{SchulzKruegerGengeJungetal., author = {Schulz, Christian and Kr{\"u}ger-Genge, Anne and Jung, Friedrich and Lendlein, Andreas}, title = {Aptamer supported in vitro endothelialization of poly(ether imide) films}, series = {Clinical Hemorheology and Microcirculation}, volume = {75}, journal = {Clinical Hemorheology and Microcirculation}, number = {2}, issn = {1875-8622}, doi = {10.3233/CH-190775}, pages = {201 -- 217}, abstract = {Implantation of synthetic small-diameter vascular bypass grafts is often associated with an increased risk of failure, due to thrombotic events or late intimal hyperplasia. As one of the causes an insufficient hemocompatibility of the artificial surface is discussed. Endothelialization of synthetic grafts is reported to be a promising strategy for creating a self-renewing and regulative anti-thrombotic graft surface. However, the establishment of a shear resistant cell monolayer is still challenging. In our study, cyto- and immuno-compatible poly(ether imide) (PEI) films were explored as potential biomaterial for cardiovascular applications. Recently, we reported that the initial adherence of primary human umbilical vein endothelial cells (HUVEC) was delayed on PEI-films and about 9 days were needed to establish a confluent and almost shear resistant HUVEC monolayer. To accelerate the initial adherence of HUVEC, the PEI-film surface was functionalized with an aptamer-cRGD peptide based endothelialization supporting system. With this functionalization the initial adherence as well as the shear resistance of HUVEC on PEI-films was considerable improved compared to the unmodified polymer surface. The in vitro results confirm the general applicability of aptamers for an efficient functionalization of substrate surfaces.}, language = {en} } @misc{JungHoeslFraunbergetal., author = {Jung, Ernst Michael and H{\"o}sl, Vanessa and Fraunberg, Sarah von and Jung, Friedrich and Prantl, Lukas}, title = {Ultrasound elastography for the detection of capsular fibrosis in breast implants: First results}, series = {Clinical Hemorheology and Microcirculation}, volume = {77(2021)}, journal = {Clinical Hemorheology and Microcirculation}, number = {3}, issn = {1386-0291}, doi = {10.3233/CH-200875}, pages = {247 -- 257}, abstract = {BACKGROUND: Capsular contractures around breast implants usually develop leading to pain and aesthetically inadequate results and ultimately often requires the replacement of the implants. Textured silicone implants are the most commonly placed implant, but polyurethane-coated implants are increasingly being used in an attempt to ameliorate the long-term complications associated with implant insertion. AIM: Capsular contracture is traditionally classified using the Baker scale, a subjective classification system based upon clinical findings. Aim of this study was to evaluate the association between pain due capsular contraction, Baker Score and different techniques of US elastography. MATERIAL AND METHODS: Patients were contacted who had undergone an implant replacement due to capsular contracture. Inclusion criterion was the re-implantation of a PU-coated implant. In the third year after changing the implant a follow-up examination was performed in 16 patients with 23 implants. A conventional examination with anamnesis, tactile and visual findings to obtain a Baker score, and ultrasound examinations including shear wave elastography, ARFI and compound elastography were performed. In addition, pain was evaluated using a visual analogue scale (VAS). RESULTS: The pain data showed a significant improvement (before implant exchange: 4.1±2.8 score points) with significance in favor of the current state (1.7±1.0 pain score points; p = 0.002). All patients suffered from less or no pain three years after exchange of the implant. Pain values and elastography (ARFI values) correlated well (r = 0,873), with increasing Baker score the ARFI values increased. US elastography evaluations can locally determine tissue density but correlate only to a limited extent with the test findings according to Baker. US elastography values of mammary gland tissue without implant did not differ from mammary gland tissue around implants. CONCLUSION: Preoperative Baker scores prior to exchange and the current Baker scores at the follow-up showed significantly lower score points three years after exchange of the implants. Ultrasound elastography seems to be an objective classification of capsular fibrosis. These first results motivate to initiate a prospective multicenter investigation.}, language = {en} } @misc{HieblKruegerGengeJung, author = {Hiebl, Bernhard and Kr{\"u}ger-Genge, Anne and Jung, Friedrich}, title = {39th conference of the German society for clinical microcirculation and hemorheology (DGKMH)}, series = {Clinical Hemorheology and Microcirculation}, volume = {76}, journal = {Clinical Hemorheology and Microcirculation}, number = {2}, issn = {1875-8622}, doi = {10.3233/ch-209200}, pages = {121 -- 122}, language = {en} } @misc{GehreFlechnerKammereretal., author = {Gehre, Christian P. and Flechner, Marie and Kammerer, Sarah and K{\"u}pper, Jan-Heiner and Coleman, Charles Dominic and P{\"u}schel, Gerhard Paul and Uhlig, Katja and Duschl, Claus}, title = {Real time monitoring of oxygen uptake of hepatocytes in a microreactor using optical microsensors}, series = {Scientific Reports}, volume = {10}, journal = {Scientific Reports}, issn = {2045-2322}, doi = {10.1038/s41598-020-70785-6}, abstract = {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.}, language = {en} } @misc{SchulteHubbertKuepperThomasetal., author = {Schulte-Hubbert, Ruth and K{\"u}pper, Jan-Heiner and Thomas, Adam D. and Schrenk, Dieter}, title = {Estragole: DNA adduct formation in primary rat hepatocytes and genotoxic potential in HepG2-CYP1A2 cells}, series = {Toxicology}, volume = {444}, journal = {Toxicology}, issn = {0300-483X}, doi = {10.1016/j.tox.2020.152566}, pages = {8}, abstract = {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.}, language = {en} } @misc{RutzGaoKuepperetal., author = {Rutz, Lukas and Gao, Lan and K{\"u}pper, Jan-Heiner and Schrenk, Dieter}, title = {Structure-dependent genotoxic potencies of selected pyrrolizidine alkaloids in metabolically competent HepG2 cells}, series = {Archives of Toxicology}, volume = {94}, journal = {Archives of Toxicology}, number = {12}, issn = {0340-5761}, doi = {10.1007/s00204-020-02895-z}, pages = {4159 -- 4172}, abstract = {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.}, language = {en} } @misc{KuenzelRauschSchaefferetal., author = {K{\"u}nzel, Stephan R. and Rausch, Johanna S. E. and Sch{\"a}ffer, Charlotte and Hoffmann, Maximilian and K{\"u}nzel, Karolina and Klapproth, Erik and Kant, Theresa and Herzog, Natalie and K{\"u}pper, Jan-Heiner and Lorenz, Kristina and Dudek, Svenja and Emig, Ramona and Ravens, Ursula and Rog-Zielinska, Eva A. and Peyronnet, R{\´e}mi and El-Armouche, Ali}, title = {Modeling atrial fibrosis in vitro - Generation and characterization of a novel human atrial fibroblast cell line}, series = {FEBS Open Bio}, volume = {10}, journal = {FEBS Open Bio}, number = {7}, issn = {2211-5463}, doi = {10.1002/2211-5463.12896}, pages = {1210 -- 1218}, abstract = {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.}, language = {en} } @misc{JungKriegerHufertetal., author = {Jung, Friedrich and Krieger, Volker and Hufert, Frank and K{\"u}pper, Jan-Heiner}, title = {How we should respond to the Coronavirus SARS-CoV-2 outbreak: A German perspective}, series = {Clinical Hemorheology and Microcirculation}, volume = {74}, journal = {Clinical Hemorheology and Microcirculation}, number = {4}, issn = {1875-8622}, doi = {10.3233/CH-209004}, pages = {363 -- 372}, abstract = {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.}, language = {en} } @misc{KuepperJungKriegeretal., author = {K{\"u}pper, Jan-Heiner and Jung, Friedrich and Krieger, Volker and Hufert, Frank}, title = {A comparison of mortality rates between European and Asian States}, series = {Clinical Hemorheology and Microcirculation}, volume = {75}, journal = {Clinical Hemorheology and Microcirculation}, number = {1}, issn = {1875-8622}, doi = {10.3233/CH-209008}, pages = {3 -- 5}, language = {en} } @misc{JungKruegerGengeFrankeetal., author = {Jung, Friedrich and Kr{\"u}ger-Genge, Anne and Franke, Ralf-Peter and Hufert, Frank and K{\"u}pper, Jan-Heiner}, title = {COVID-19 and the endothelium}, series = {Clinical Hemorheology and Microcirculation}, volume = {75}, journal = {Clinical Hemorheology and Microcirculation}, number = {1}, issn = {1875-8622}, doi = {10.3233/CH-209007}, pages = {7 -- 11}, abstract = {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.}, language = {en} } @misc{JungKriegerHufertetal., author = {Jung, Friedrich and Krieger, Volker and Hufert, Frank and K{\"u}pper, Jan-Heiner}, title = {Herd immunity or suppression strategy to combat COVID-19}, series = {Clinical Hemorheology and Microcirculation}, volume = {75}, journal = {Clinical Hemorheology and Microcirculation}, number = {1}, issn = {1875-8622}, doi = {10.3233/CH-209006}, pages = {13 -- 17}, abstract = {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).}, language = {en} } @misc{SteinbrechtKiebistKoenigetal., author = {Steinbrecht, Susanne and Kiebist, Jan and K{\"o}nig, Rosalie and Thiessen, Markus and Schmidtke, Kai-Uwe and Kammerer, Sarah and K{\"u}pper, Jan-Heiner and Scheibner, Katrin}, title = {Synthesis of cyclophosphamide metabolites by a peroxygenase from Marasmius rotula for toxicological studies on human cancer cells}, series = {AMB Express}, volume = {10}, journal = {AMB Express}, issn = {2191-0855}, doi = {10.1186/s13568-020-01064-w}, pages = {13}, abstract = {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.}, language = {en} }