TY - JOUR A1 - Schmitz, Tobias A1 - Jannasch, Maren A1 - Weigel, Tobias A1 - Moseke, Claus A1 - Gbureck, Uwe A1 - Groll, Jürgen A1 - Walles, Heike A1 - Hansmann, Jan T1 - Nanotopographical Coatings Induce an Early Phenotype-Specific Response of Primary Material-Resident M1 and M2 Macrophages JF - Materials N2 - Implants elicit an immunological response after implantation that results in the worst case in a complete implant rejection. This biomaterial-induced inflammation is modulated by macrophages and can be influenced by nanotopographical surface structures such as titania nanotubes or fractal titanium nitride (TiN) surfaces. However, their specific impact on a distinct macrophage phenotype has not been identified. By using two different levels of nanostructures and smooth samples as controls, the influence of tubular TiO2 and fractal TiN nanostructures on primary human macrophages with M1 or M2-phenotype was investigated. Therefore, nanotopographical coatings were either, directly generated by physical vapor deposition (PVD) or by electrochemical anodization of titanium PVD coatings. The cellular response of macrophages was quantitatively assessed to demonstrate a difference in biocompatibility of nanotubes in respect to human M1 and M2-macrophages. Depending on the tube diameter of the nanotubular surfaces, low cell numbers and impaired cellular activity, was detected for M2-macrophages, whereas the impact of nanotubes on M1-polarized macrophages was negligible. Importantly, we could confirm this phenotypic response on the fractal TiN surfaces. The results indicate that the investigated topographies specifically impact the macrophage M2-subtype that modulates the formation of the fibrotic capsule and the long-term response to an implant. KW - nanotopographical surfaces KW - combination of physical vapor deposition and electrochemical etching KW - defined humanized test system KW - inflammatory response Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-203378 SN - 1996-1944 VL - 13 IS - 5 ER - TY - JOUR A1 - Kühnemundt, Johanna A1 - Leifeld, Heidi A1 - Scherg, Florian A1 - Schmitt, Matthias A1 - Nelke, Lena C. A1 - Schmitt, Tina A1 - Bauer, Florentin A1 - Göttlich, Claudia A1 - Fuchs, Maximilian A1 - Kunz, Meik A1 - Peindl, Matthias A1 - Brähler, Caroline A1 - Kronenthaler, Corinna A1 - Wischhusen, Jörg A1 - Prelog, Martina A1 - Walles, Heike A1 - Dandekar, Thomas A1 - Dandekar, Gudrun A1 - Nietzer, Sarah L. T1 - Modular micro-physiological human tumor/tissue models based on decellularized tissue for improved preclinical testing JF - ALTEX N2 - High attrition-rates entailed by drug testing in 2D cell culture and animal models stress the need for improved modeling of human tumor tissues. In previous studies our 3D models on a decellularized tissue matrix have shown better predictivity and higher chemoresistance. A single porcine intestine yields material for 150 3D models of breast, lung, colorectal cancer (CRC) or leukemia. The uniquely preserved structure of the basement membrane enables physiological anchorage of endothelial cells and epithelial-derived carcinoma cells. The matrix provides different niches for cell growth: on top as monolayer, in crypts as aggregates and within deeper layers. Dynamic culture in bioreactors enhances cell growth. Comparing gene expression between 2D and 3D cultures, we observed changes related to proliferation, apoptosis and stemness. For drug target predictions, we utilize tumor-specific sequencing data in our in silico model finding an additive effect of metformin and gefitinib treatment for lung cancer in silico, validated in vitro. To analyze mode-of-action, immune therapies such as trispecific T-cell engagers in leukemia, as well as toxicity on non-cancer cells, the model can be modularly enriched with human endothelial cells (hECs), immune cells and fibroblasts. Upon addition of hECs, transmigration of immune cells through the endothelial barrier can be investigated. In an allogenic CRC model we observe a lower basic apoptosis rate after applying PBMCs in 3D compared to 2D, which offers new options to mirror antigen-specific immunotherapies in vitro. In conclusion, we present modular human 3D tumor models with tissue-like features for preclinical testing to reduce animal experiments. KW - modular tumor tissue models KW - invasiveness KW - bioreactor culture KW - combinatorial drug predictions KW - immunotherapies Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-231465 VL - 38 ER - TY - JOUR A1 - Nietzer, Sarah A1 - Baur, Florentin A1 - Sieber, Stefan A1 - Hansmann, Jan A1 - Schwarz, Thomas A1 - Stoffer, Carolin A1 - Häfner, Heide A1 - Gasser, Martin A1 - Waaga-Gasser, Ana Maria A1 - Walles, Heike A1 - Dandekar, Gudrun T1 - Mimicking metastases including tumor stroma: a new technique to generate a three-dimensional colorectal cancer model based on a biological decellularized intestinal scaffold JF - Tissue Engineering Part C-Methods N2 - Tumor models based on cancer cell lines cultured two-dimensionally (2D) on plastic lack histological complexity and functionality compared to the native microenvironment. Xenogenic mouse tumor models display higher complexity but often do not predict human drug responses accurately due to species-specific differences. We present here a three-dimensional (3D) in vitro colon cancer model based on a biological scaffold derived from decellularized porcine jejunum (small intestine submucosa+mucosa, SISmuc). Two different cell lines were used in monoculture or in coculture with primary fibroblasts. After 14 days of culture, we demonstrated a close contact of human Caco2 colon cancer cells with the preserved basement membrane on an ultrastructural level as well as morphological characteristics of a well-differentiated epithelium. To generate a tissue-engineered tumor model, we chose human SW480 colon cancer cells, a reportedly malignant cell line. Malignant characteristics were confirmed in 2D cell culture: SW480 cells showed higher vimentin and lower E-cadherin expression than Caco2 cells. In contrast to Caco2, SW480 cells displayed cancerous characteristics such as delocalized E-cadherin and nuclear location of beta-catenin in a subset of cells. One central drawback of 2D cultures-especially in consideration of drug testing-is their artificially high proliferation. In our 3D tissue-engineered tumor model, both cell lines showed decreased numbers of proliferating cells, thus correlating more precisely with observations of primary colon cancer in all stages (UICC I-IV). Moreover, vimentin decreased in SW480 colon cancer cells, indicating a mesenchymal to epithelial transition process, attributed to metastasis formation. Only SW480 cells cocultured with fibroblasts induced the formation of tumor-like aggregates surrounded by fibroblasts, whereas in Caco2 cocultures, a separate Caco2 cell layer was formed separated from the fibroblast compartment beneath. To foster tissue generation, a bioreactor was constructed for dynamic culture approaches. This induced a close tissue-like association of cultured tumor cells with fibroblasts reflecting tumor biopsies. Therapy with 5-fluorouracil (5-FU) was effective only in 3D coculture. In conclusion, our 3D tumor model reflects human tissue-related tumor characteristics, including lower tumor cell proliferation. It is now available for drug testing in metastatic context-especially for substances targeting tumor-stroma interactions. KW - Multicenter randomized-trial KW - Carcinoma cells KW - Tissue KW - Fluorouracil KW - Matrix KW - 1st-line treatment KW - Beta-catenin KW - Invasion KW - 5-Fluorouracil KW - Fibroblasts Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-188202 VL - 22 IS - 7 ER - TY - JOUR A1 - Wallstabe, Julia A1 - Bussemer, Lydia A1 - Groeber-Becker, Florian A1 - Freund, Lukas A1 - Alb, Mirian A1 - Dragan, Mariola A1 - Waaga-Gasser, Ana Maria A1 - Jakubietz, Rafael A1 - Kneitz, Hermann A1 - Rosenwald, Andreas A1 - Rebhan, Silke A1 - Walles, Heike A1 - Mielke, Stephan T1 - Inflammation-Induced Tissue Damage Mimicking GvHD in Human Skin Models as Test Platform for Immunotherapeutics JF - ALTEX N2 - Due to the rapidly increasing development and use of cellular products, there is a rising demand for non-animal-based test platforms to predict, study and treat undesired immunity. Here, we generated human organotypic skin models from human biopsies by isolating and expanding keratinocytes, fibroblasts and microvascular endothelial cells and seeding these components on a collagen matrix or a biological vascularized scaffold matrix in a bioreactor. We then were able to induce inflammation-mediated tissue damage by adding pre-stimulated, mismatched allogeneic lymphocytes and/or inflammatory cytokine-containing supernatants histomorphologically mimicking severe graft versus host disease (GvHD) of the skin. This could be prevented by the addition of immunosuppressants to the models. Consequently, these models harbor a promising potential to serve as a test platform for the prediction, prevention and treatment of GvHD. They also allow functional studies of immune effectors and suppressors including but not limited to allodepleted lymphocytes, gamma-delta T cells, regulatory T cells and mesenchymal stromal cells, which would otherwise be limited to animal models. Thus, the current test platform, developed with the limitation that no professional antigen presenting cells are in place, could greatly reduce animal testing for investigation of novel immune therapies. KW - inflammation-induced tissue demage KW - immunotherapeutics Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-229974 VL - 37 IS - 3 ER - TY - JOUR A1 - Ramachandran, Sarada Devi A1 - Schirmer, Katharina A1 - Münst, Bernhard A1 - Heinz, Stefan A1 - Ghafoory, Shahrouz A1 - Wölfl, Stefan A1 - Simon-Keller, Katja A1 - Marx, Alexander A1 - Øie, Cristina Ionica A1 - Ebert, Matthias P. A1 - Walles, Heike A1 - Braspenning, Joris A1 - Breitkopf-Heinlein, Katja T1 - In Vitro Generation of Functional Liver Organoid-Like Structures Using Adult Human Cells JF - PLoS One N2 - In this study we used differentiated adult human upcyte (R) cells for the in vitro generation of liver organoids. Upcyte (R) cells are genetically engineered cell strains derived from primary human cells by lenti-viral transduction of genes or gene combinations inducing transient proliferation capacity (upcyte (R) process). Proliferating upcyte (R) cells undergo a finite number of cell divisions, i.e., 20 to 40 population doublings, but upon withdrawal of proliferation stimulating factors, they regain most of the cell specific characteristics of primary cells. When a defined mixture of differentiated human upcyte (R) cells (hepatocytes, liver sinusoidal endothelial cells (LSECs) and mesenchymal stem cells (MSCs)) was cultured in vitro on a thick layer of Matrigel\(^{TM}\), they self-organized to form liver organoid-like structures within 24 hours. When further cultured for 10 days in a bioreactor, these liver organoids show typical functional characteristics of liver parenchyma including activity of cytochromes P450, CYP3A4, CYP2B6 and CYP2C9 as well as mRNA expression of several marker genes and other enzymes. In summary, we hereby describe that 3D functional hepatic structures composed of primary human cell strains can be generated in vitro. They can be cultured for a prolonged period of time and are potentially useful ex vivo models to study liver functions. KW - adults KW - enzyme metabolism KW - albumins KW - primary cells KW - induction KW - expression KW - human heptocytes KW - mesenchymal stem cells KW - oragnoids KW - heptaocytes KW - drug metabolism Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-139552 VL - 10 IS - 10 ER - TY - JOUR A1 - Jakob, Franz A1 - Ebert, Regina A1 - Rudert, Maximilian A1 - Nöth, Ulrich A1 - Walles, Heike A1 - Docheva, Denitsa A1 - Schieker, Matthias A1 - Meinel, Lorenz A1 - Groll, Jürgen T1 - In situ guided tissue regeneration in musculoskeletal diseases and aging JF - Cell and Tissue Research N2 - In situ guided tissue regeneration, also addressed as in situ tissue engineering or endogenous regeneration, has a great potential for population-wide “minimal invasive” applications. During the last two decades, tissue engineering has been developed with remarkable in vitro and preclinical success but still the number of applications in clinical routine is extremely small. Moreover, the vision of population-wide applications of ex vivo tissue engineered constructs based on cells, growth and differentiation factors and scaffolds, must probably be deemed unrealistic for economic and regulation-related issues. Hence, the progress made in this respect will be mostly applicable to a fraction of post-traumatic or post-surgery situations such as big tissue defects due to tumor manifestation. Minimally invasive procedures would probably qualify for a broader application and ideally would only require off the shelf standardized products without cells. Such products should mimic the microenvironment of regenerating tissues and make use of the endogenous tissue regeneration capacities. Functionally, the chemotaxis of regenerative cells, their amplification as a transient amplifying pool and their concerted differentiation and remodeling should be addressed. This is especially important because the main target populations for such applications are the elderly and diseased. The quality of regenerative cells is impaired in such organisms and high levels of inhibitors also interfere with regeneration and healing. In metabolic bone diseases like osteoporosis, it is already known that antagonists for inhibitors such as activin and sclerostin enhance bone formation. Implementing such strategies into applications for in situ guided tissue regeneration should greatly enhance the efficacy of tailored procedures in the future. KW - in situ guided tissue regeneration KW - stem cells KW - scaffolds KW - regenerative medicine KW - mesenchymal tissues Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-124738 VL - 347 IS - 3 ER - TY - JOUR A1 - Fecher, David A1 - Hofmann, Elisabeth A1 - Buck, Andreas A1 - Bundschuh, Ralph A1 - Nietzer, Sarah A1 - Dandekar, Gudrun A1 - Walles, Thorsten A1 - Walles, Heike A1 - Lückerath, Katharina A1 - Steinke, Maria T1 - Human Organotypic Lung Tumor Models: Suitable For Preclinical \(^{18}\)F-FDG PET-Imaging JF - PLoS ONE N2 - Development of predictable in vitro tumor models is a challenging task due to the enormous complexity of tumors in vivo. The closer the resemblance of these models to human tumor characteristics, the more suitable they are for drug-development and –testing. In the present study, we generated a complex 3D lung tumor test system based on acellular rat lungs. A decellularization protocol was established preserving the architecture, important ECM components and the basement membrane of the lung. Human lung tumor cells cultured on the scaffold formed cluster and exhibited an up-regulation of the carcinoma-associated marker mucin1 as well as a reduced proliferation rate compared to respective 2D culture. Additionally, employing functional imaging with 2-deoxy-2-[\(^{18}\)F]fluoro-D-glucose positron emission tomography (FDG-PET) these tumor cell cluster could be detected and tracked over time. This approach allowed monitoring of a targeted tyrosine kinase inhibitor treatment in the in vitro lung tumor model non-destructively. Surprisingly, FDG-PET assessment of single tumor cell cluster on the same scaffold exhibited differences in their response to therapy, indicating heterogeneity in the lung tumor model. In conclusion, our complex lung tumor test system features important characteristics of tumors and its microenvironment and allows monitoring of tumor growth and -metabolism in combination with functional imaging. In longitudinal studies, new therapeutic approaches and their long-term effects can be evaluated to adapt treatment regimes in future. KW - lung and intrathoracic tumors KW - trachea KW - adenocarcinoma of the lung KW - cancer treatment KW - secondary lung tumors KW - pulmonary imaging KW - extracellular matrix KW - collagens Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-179678 VL - 11 IS - 8 ER - TY - JOUR A1 - Brendtke, Rico A1 - Wiehl, Michael A1 - Groeber, Florian A1 - Schwarz, Thomas A1 - Walles, Heike A1 - Hansmann, Jan T1 - Feasibility Study on a Microwave-Based Sensor for Measuring Hydration Level Using Human Skin Models JF - PLoS ONE N2 - Tissue dehydration results in three major types of exsiccosis—hyper-, hypo-, or isonatraemia. All three types entail alterations of salt concentrations leading to impaired biochemical processes, and can finally cause severe morbidity. The aim of our study was to demonstrate the feasibility of a microwave-based sensor technology for the non-invasive measurement of the hydration status. Electromagnetic waves at high frequencies interact with molecules, especially water. Hence, if a sample contains free water molecules, this can be detected in a reflected microwave signal. To develop the sensor system, human three-dimensional skin equivalents were instituted as a standardized test platform mimicking reproducible exsiccosis scenarios. Therefore, skin equivalents with a specific hydration and density of matrix components were generated and microwave measurements were performed. Hydration-specific spectra allowed deriving the hydration state of the skin models. A further advantage of the skin equivalents was the characterization of the impact of distinct skin components on the measured signals to investigate mechanisms of signal generation. The results demonstrate the feasibility of a non-invasive microwave-based hydration sensor technology. The sensor bears potential to be integrated in a wearable medical device for personal health monitoring. KW - gels KW - microwave radiation KW - collagens KW - skin physiology KW - reflection KW - skin anatomy KW - epidermis KW - antennas Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-179934 VL - 11 IS - 4 ER - TY - JOUR A1 - Schwab, Andrea A1 - Meeuwsen, Annick A1 - Ehlicke, Franziska A1 - Hansmann, Jan A1 - Mulder, Lars A1 - Smits, Anthal A1 - Walles, Heike A1 - Kock, Linda T1 - Ex vivo culture platform for assessment of cartilage repair treatment strategies JF - ALTEX - Alternatives to animal experimentation N2 - There is a great need for valuable ex vivo models that allow for assessment of cartilage repair strategies to reduce the high number of animal experiments. In this paper we present three studies with our novel ex vivo osteochondral culture platform. It consists of two separated media compartments for cartilage and bone, which better represents the in vivo situation and enables supply of factors pecific to the different needs of bone and cartilage. We investigated whether separation of the cartilage and bone compartments and/or culture media results in the maintenance of viability, structural and functional properties of cartilage tissue. Next, we valuated for how long we can preserve cartilage matrix stability of osteochondral explants during long-term culture over 84 days. Finally, we determined the optimal defect size that does not show spontaneous self-healing in this culture system. It was demonstrated that separated compartments for cartilage and bone in combination with tissue-specific medium allow for long-term culture of osteochondral explants while maintaining cartilage viability, atrix tissue content, structure and mechanical properties for at least 56 days. Furthermore, we could create critical size cartilage defects of different sizes in the model. The osteochondral model represents a valuable preclinical ex vivo tool for studying clinically relevant cartilage therapies, such as cartilage biomaterials, for their regenerative potential, for evaluation of drug and cell therapies, or to study mechanisms of cartilage regeneration. It will undoubtedly reduce the number of animals needed for in vivotesting. KW - ex vivo model KW - osteochondral biopsy KW - cartilage repair KW - critical size defect KW - replacement Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-181665 VL - 34 IS - 2 ER - TY - JOUR A1 - Kress, Sebastian A1 - Baur, Johannes A1 - Otto, Christoph A1 - Burkard, Natalie A1 - Braspenning, Joris A1 - Walles, Heike A1 - Nickel, Joachim A1 - Metzger, Marco T1 - Evaluation of a miniaturized biologically vascularized scaffold in vitro and in vivo JF - Scientific Reports N2 - In tissue engineering, the generation and functional maintenance of dense voluminous tissues is mainly restricted due to insufficient nutrient supply. Larger three-dimensional constructs, which exceed the nutrient diffusion limit become necrotic and/or apoptotic in long-term culture if not provided with an appropriate vascularization. Here, we established protocols for the generation of a pre-vascularized biological scaffold with intact arterio-venous capillary loops from rat intestine, which is decellularized under preservation of the feeding and draining vascular tree. Vessel integrity was proven by marker expression, media/blood reflow and endothelial LDL uptake. In vitro maintenance persisted up to 7 weeks in a bioreactor system allowing a stepwise reconstruction of fully vascularized human tissues and successful in vivo implantation for up to 4 weeks, although with time-dependent decrease of cell viability. The vascularization of the construct lead to a 1.5× increase in cellular drug release compared to a conventional static culture in vitro. For the first time, we performed proof-of-concept studies demonstrating that 3D tissues can be maintained within a miniaturized vascularized scaffold in vitro and successfully implanted after re-anastomosis to the intrinsic blood circulation in vivo. We hypothesize that this technology could serve as a powerful platform technology in tissue engineering and regenerative medicine. KW - biological models KW - translational research Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-176343 VL - 8 IS - 4719 ER - TY - JOUR A1 - Appelt-Menzel, Antje A1 - Cubukova, Alevtina A1 - Günther, Katharina A1 - Edenhofer, Frank A1 - Piontek, Jörg A1 - Krause, Gerd A1 - Stüber, Tanja A1 - Walles, Heike A1 - Neuhaus, Winfried A1 - Metzger, Marco T1 - Establishment of a Human Blood-Brain Barrier Co-culture Model Mimicking the Neurovascular Unit Using Induced Pluri- and Multipotent Stem Cells JF - Stem Cell Reports N2 - In vitro models of the human blood-brain barrier (BBB) are highly desirable for drug development. This study aims to analyze a set of ten different BBB culture models based on primary cells, human induced pluripotent stem cells (hiPSCs), and multipotent fetal neural stem cells (fNSCs). We systematically investigated the impact of astrocytes, pericytes, and NSCs on hiPSC-derived BBB endothelial cell function and gene expression. The quadruple culture models, based on these four cell types, achieved BBB characteristics including transendothelial electrical resistance (TEER) up to 2,500 Ω cm\(^{2}\) and distinct upregulation of typical BBB genes. A complex in vivo-like tight junction (TJ) network was detected by freeze-fracture and transmission electron microscopy. Treatment with claudin-specific TJ modulators caused TEER decrease, confirming the relevant role of claudin subtypes for paracellular tightness. Drug permeability tests with reference substances were performed and confirmed the suitability of the models for drug transport studies. KW - blood-brain barrier (BBB) model KW - human induced pluripotent stem cells (hiPSCs)human induced pluripotent stem cells (hiPSCs) KW - multipotent fetal neural stem cells (fNSCs) KW - neurovascular unit in vitro Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170982 VL - 8 IS - 4 ER - TY - JOUR A1 - Baur, Florentin A1 - Nietzer, Sarah L. A1 - Kunz, Meik A1 - Saal, Fabian A1 - Jeromin, Julian A1 - Matschos, Stephanie A1 - Linnebacher, Michael A1 - Walles, Heike A1 - Dandekar, Thomas A1 - Dandekar, Gudrun T1 - Connecting cancer pathways to tumor engines: a stratification tool for colorectal cancer combining human in vitro tissue models with boolean in silico models JF - Cancers N2 - To improve and focus preclinical testing, we combine tumor models based on a decellularized tissue matrix with bioinformatics to stratify tumors according to stage-specific mutations that are linked to central cancer pathways. We generated tissue models with BRAF-mutant colorectal cancer (CRC) cells (HROC24 and HROC87) and compared treatment responses to two-dimensional (2D) cultures and xenografts. As the BRAF inhibitor vemurafenib is—in contrast to melanoma—not effective in CRC, we combined it with the EGFR inhibitor gefitinib. In general, our 3D models showed higher chemoresistance and in contrast to 2D a more active HGFR after gefitinib and combination-therapy. In xenograft models murine HGF could not activate the human HGFR, stressing the importance of the human microenvironment. In order to stratify patient groups for targeted treatment options in CRC, an in silico topology with different stages including mutations and changes in common signaling pathways was developed. We applied the established topology for in silico simulations to predict new therapeutic options for BRAF-mutated CRC patients in advanced stages. Our in silico tool connects genome information with a deeper understanding of tumor engines in clinically relevant signaling networks which goes beyond the consideration of single drivers to improve CRC patient stratification. KW - in silico simulation KW - 3D tissue models KW - colorectal cancer KW - BRAF mutation KW - targeted therapy KW - stratification Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-193798 SN - 2072-6694 VL - 12 IS - 1 ER - TY - JOUR A1 - Groeber, Florian A1 - Schober, Lena A1 - Schmid, Freia F. A1 - Traube, Andrea A1 - Kolbus-Hernandez, Silvia A1 - Daton, Karolina A1 - Hoffmann, Sebastian A1 - Petersohn, Dirk A1 - Schaefer-Korting, Monika A1 - Walles, Heike A1 - Mewes, Karsten R. T1 - Catch-up validation study of an in vitro skin irritation test method based on an open source reconstructed epidermis (phase II) JF - Toxicology in Vitro N2 - To replace the Draize skin irritation assay (OECD guideline 404) several test methods based on reconstructed human epidermis (RHE) have been developed and were adopted in the OECD test guideline 439. However, all validated test methods in the guideline are linked to RHE provided by only three companies. Thus,the availability of these test models is dependent on the commercial interest of the producer. To overcome this limitation and thus to increase the accessibility of in vitro skin irritation testing, an open source reconstructed epidermis (OS-REp) was introduced. To demonstrate the capacity of the OS-REp in regulatory risk assessment, a catch-up-validation study was performed. The participating laboratories used in-house generated OS-REp to assess the set of 20 reference substances according to the performance standards amending the OECD test guideline 439. Testing was performed under blinded conditions. The within-laboratory reproducibility of 87% and the inter-laboratory reproducibility of 85% prove a high reliability of irritancy testing using the OS-REp protocol. In addition, the prediction capacity was with an accuracy of 80% comparable to previous published RHE based test protocols. Taken together the results indicate that the OS-REp test method can be used as a standalone alternative skin irritation test replacing the OECD test guideline 404. KW - Model KW - Chemicals KW - Assay KW - Episkin KW - Vivo KW - RHE KW - In vitro skin irritation testing KW - Open source reconstructed epidermis KW - Validation KW - Alternative test methods Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-187311 VL - 36 ER - TY - JOUR A1 - Straßer, Marion A1 - Schrauth, Joachim H. X. A1 - Dembski, Sofia A1 - Haddad, Daniel A1 - Ahrens, Bernd A1 - Schweizer, Stefan A1 - Christ, Bastian A1 - Cubukova, Alevtina A1 - Metzger, Marco A1 - Walles, Heike A1 - Jakob, Peter M. A1 - Sextl, Gerhard T1 - Calcium fluoride based multifunctional nanoparticles for multimodal imaging JF - Beilstein Journal of Nanotechnology N2 - New multifunctional nanoparticles (NPs) that can be used as contrast agents (CA) in different imaging techniques, such as photoluminescence (PL) microscopy and magnetic resonance imaging (MRI), open new possibilities for medical imaging, e.g., in the fields of diagnostics or tissue characterization in regenerative medicine. The focus of this study is on the synthesis and characterization of CaF\(_{2}\):(Tb\(^{3+}\),Gd\(^{3+}\)) NPs. Fabricated in a wet-chemical procedure, the spherical NPs with a diameter of 5–10 nm show a crystalline structure. Simultaneous doping of the NPs with different lanthanide ions, leading to paramagnetism and fluorescence, makes them suitable for MR and PL imaging. Owing to the Gd\(^{3+}\) ions on the surface, the NPs reduce the MR T\(_{1}\) relaxation time constant as a function of their concentration. Thus, the NPs can be used as a MRI CA with a mean relaxivity of about r = 0.471 mL·mg\(^{−1}\)·s\(^{−1}\). Repeated MRI examinations of four different batches prove the reproducibility of the NP synthesis and determine the long-term stability of the CAs. No cytotoxicity of NP concentrations between 0.5 and 1 mg·mL\(^{−1}\) was observed after exposure to human dermal fibroblasts over 24 h. Overall this study shows, that the CaF\(_{2}\):(Tb\(^{3+}\),Gd\(^{3+}\)) NPs are suitable for medical imaging. KW - calcium fluoride nanoparticles KW - magnetic resonance imaging (MRI) KW - multifunctional nanoparticles KW - multimodal imaging KW - photoluminescence Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170657 VL - 8 ER - TY - JOUR A1 - Heydarian, Motaharehsadat A1 - Yang, Tao A1 - Schweinlin, Matthias A1 - Steinke, Maria A1 - Walles, Heike A1 - Rudel, Thomas A1 - Kozjak-Pavlovic, Vera T1 - Biomimetic human tissue model for long-term study of Neisseria gonorrhoeae infection JF - Frontiers in Microbiology N2 - Gonorrhea is the second most common sexually transmitted infection in the world and is caused by Gram-negative diplococcus Neisseria gonorrhoeae. Since N. gonorrhoeae is a human-specific pathogen, animal infection models are only of limited use. Therefore, a suitable in vitro cell culture model for studying the complete infection including adhesion, transmigration and transport to deeper tissue layers is required. In the present study, we generated three independent 3D tissue models based on porcine small intestinal submucosa (SIS) scaffold by co-culturing human dermal fibroblasts with human colorectal carcinoma, endometrial epithelial, and male uroepithelial cells. Functional analyses such as transepithelial electrical resistance (TEER) and FITC-dextran assay indicated the high barrier integrity of the created monolayer. The histological, immunohistochemical, and ultra-structural analyses showed that the 3D SIS scaffold-based models closely mimic the main characteristics of the site of gonococcal infection in human host including the epithelial monolayer, the underlying connective tissue, mucus production, tight junction, and microvilli formation. We infected the established 3D tissue models with different N. gonorrhoeae strains and derivatives presenting various phenotypes regarding adhesion and invasion. The results indicated that the disruption of tight junctions and increase in interleukin production in response to the infection is strain and cell type-dependent. In addition, the models supported bacterial survival and proved to be better suitable for studying infection over the course of several days in comparison to commonly used Transwell® models. This was primarily due to increased resilience of the SIS scaffold models to infection in terms of changes in permeability, cell destruction and bacterial transmigration. In summary, the SIS scaffold-based 3D tissue models of human mucosal tissues represent promising tools for investigating N. gonorrhoeae infections under close-to-natural conditions. KW - 3D tissue model KW - small intestinal submucosa scaffold KW - co-culture KW - infection KW - Neisseria gonorrhoeae Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-197912 SN - 1664-302X VL - 10 IS - 1740 ER - TY - JOUR A1 - Schwedhelm, Ivo A1 - Zdzieblo, Daniela A1 - Appelt-Menzel, Antje A1 - Berger, Constantin A1 - Schmitz, Tobias A1 - Schuldt, Bernhard A1 - Franke, Andre A1 - Müller, Franz-Josef A1 - Pless, Ole A1 - Schwarz, Thomas A1 - Wiedemann, Philipp A1 - Walles, Heike A1 - Hansmann, Jan T1 - Automated real-time monitoring of human pluripotent stem cell aggregation in stirred tank reactors JF - Scientific Reports N2 - The culture of human induced pluripotent stem cells (hiPSCs) at large scale becomes feasible with the aid of scalable suspension setups in continuously stirred tank reactors (CSTRs). Innovative monitoring options and emerging automated process control strategies allow for the necessary highly defined culture conditions. Next to standard process characteristics such as oxygen consumption, pH, and metabolite turnover, a reproducible and steady formation of hiPSC aggregates is vital for process scalability. In this regard, we developed a hiPSC-specific suspension culture unit consisting of a fully monitored CSTR system integrated into a custom-designed and fully automated incubator. As a step towards cost-effective hiPSC suspension culture and to pave the way for flexibility at a large scale, we constructed and utilized tailored miniature CSTRs that are largely made from three-dimensional (3D) printed polylactic acid (PLA) filament, which is a low-cost material used in fused deposition modelling. Further, the monitoring tool for hiPSC suspension cultures utilizes in situ microscopic imaging to visualize hiPSC aggregation in real-time to a statistically significant degree while omitting the need for time-intensive sampling. Suitability of our culture unit, especially concerning the developed hiPSC-specific CSTR system, was proven by demonstrating pluripotency of CSTR-cultured hiPSCs at RNA (including PluriTest) and protein level. KW - Biomedical engineering KW - Stem-cell biotechnology Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-202649 VL - 9 ER - TY - JOUR A1 - Ramachandran, Sarada D. A1 - Vivarès, Aurélie A1 - Klieber, Sylvie A1 - Hewitt, Nicola J. A1 - Muenst, Bernhard A1 - Heinz, Stefan A1 - Walles, Heike A1 - Braspenning, Joris T1 - Applicability of second-generation upcyte\(^{®}\) human hepatocytes for use in CYP inhibition and induction studies JF - Pharmacology Research & Perspectives N2 - Human upcyte\(^{®}\) hepatocytes are proliferating hepatocytes that retain many characteristics of primary human hepatocytes. We conducted a comprehensive evaluation of the application of second-generation upcyte\(^{®}\) hepatocytes from four donors for inhibition and induction assays using a selection of reference inhibitors and inducers. CYP1A2, CYP2B6, CYP2C9, and CYP3A4 were reproducibly inhibited in a concentration-dependent manner and the calculated IC\(_{50}\) values for each compound correctly classified them as potent inhibitors. Upcyte\(^{®}\) hepatocytes were responsive to prototypical CYP1A2, CYP2B6, CYP2C9, and CYP3A4 inducers, confirming that they have functional AhR-, CAR-, and PXR-mediated CYP regulation. A panel of 11 inducers classified as potent, moderate or noninducers of CYP3A4 and CYP2B6 were tested. There was a good fit of data from upcyte\(^{®}\) hepatocytes to three different predictive models for CYP3A4 induction, namely the Relative Induction Score (RIS), AUC\(_{u}\)/F\(_{2}\), and C\(_{max,u}\)/Ind\(_{50}\). In addition, PXR (rifampicin) and CAR-selective (carbamazepine and phenytoin) inducers of CYP3A4 and CYP2B6 induction, respectively, were demonstrated. In conclusion, these data support the use of second-generation upcyte\(^{®}\) hepatocytes for CYP inhibition and induction assays. Under the culture conditions used, these cells expressed CYP activities that were equivalent to or higher than those measured in primary human hepatocyte cultures, which could be inhibited or induced by prototypical CYP inhibitors and inducers, respectively. Moreover, they can be used to predict in vivo CYP3A4 induction potential using three prediction models. Bulk availability of cells from multiple donors makes upcyte\(^{®}\) hepatocytes suitable for DDI screening, as well as more in-depth mechanistic investigations. KW - upcyte hepatocytes KW - CYP induction KW - CYP inhibition KW - human Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-149564 VL - 3 IS - 5 ER - TY - JOUR A1 - Schulte, Leon N. A1 - Schweinlin, Matthias A1 - Westermann, Alexander J. A1 - Janga, Harshavardhan A1 - Santos, Sara C. A1 - Appenzeller, Silke A1 - Walles, Heike A1 - Vogel, Jörg A1 - Metzger, Marco T1 - An Advanced Human Intestinal Coculture Model Reveals Compartmentalized Host and Pathogen Strategies during Salmonella Infection JF - mBio N2 - A major obstacle in infection biology is the limited ability to recapitulate human disease trajectories in traditional cell culture and animal models, which impedes the translation of basic research into clinics. Here, we introduce a three-dimensional (3D) intestinal tissue model to study human enteric infections at a level of detail that is not achieved by conventional two-dimensional monocultures. Our model comprises epithelial and endothelial layers, a primary intestinal collagen scaffold, and immune cells. Upon Salmonella infection, the model mimics human gastroenteritis, in that it restricts the pathogen to the epithelial compartment, an advantage over existing mouse models. Application of dual transcriptome sequencing to the Salmonella-infected model revealed the communication of epithelial, endothelial, monocytic, and natural killer cells among each other and with the pathogen. Our results suggest that Salmonella uses its type III secretion systems to manipulate STAT3-dependent inflammatory responses locally in the epithelium without accompanying alterations in the endothelial compartment. Our approach promises to reveal further human-specific infection strategies employed by Salmonella and other pathogens. IMPORTANCE Infection research routinely employs in vitro cell cultures or in vivo mouse models as surrogates of human hosts. Differences between murine and human immunity and the low level of complexity of traditional cell cultures, however, highlight the demand for alternative models that combine the in vivo-like properties of the human system with straightforward experimental perturbation. Here, we introduce a 3D tissue model comprising multiple cell types of the human intestinal barrier, a primary site of pathogen attack. During infection with the foodborne pathogen Salmonella enterica serovar Typhimurium, our model recapitulates human disease aspects, including pathogen restriction to the epithelial compartment, thereby deviating from the systemic infection in mice. Combination of our model with state-of-the-art genetics revealed Salmonella-mediated local manipulations of human immune responses, likely contributing to the establishment of the pathogen's infection niche. We propose the adoption of similar 3D tissue models to infection biology, to advance our understanding of molecular infection strategies employed by bacterial pathogens in their human host. KW - Salmonella KW - gene expression KW - infectious disease Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-229428 VL - 11, 2020 IS - 1 ER - TY - JOUR A1 - Lotz, Christian A1 - Schmid, Freia F. A1 - Rossi, Angela A1 - Kurdyn, Szymon A1 - Kampik, Daniel A1 - De Wever, Bart A1 - Walles, Heike A1 - Groeber, Florian K. T1 - Alternative Methods for the Replacement of Eye Irritation Testing JF - ALTEX - Alternatives to Animal Experimentation N2 - In the last decades significant regulatory attempts were made to replace, refine and reduce animal testing to assess the risk of consumer products for the human eye. As the original in vivo Draize eye test is criticized for limited predictivity, costs and ethical issues, several animal-free test methods have been developed to categorize substances according to the global harmonized system (GHS) for eye irritation. This review summarizes the progress of alternative test methods for the assessment of eye irritation. Based on the corneal anatomy and current knowledge of the mechanisms causing eye irritation, different ex vivo and in vitro methods will be presented and discussed with regard to possible limitations and status of regulatory acceptance. In addition to established in vitro models, this review will also highlight emerging, full thickness cornea models that might be suited to predict all GHS categories. KW - eye irritation testing KW - alternatives KW - Draize eye test KW - OECD guideline KW - corneal equivalent Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-164444 VL - 33 IS - 1 ER - TY - JOUR A1 - Rosenbaum, Corinna A1 - Schick, Martin Alexander A1 - Wollborn, Jakob A1 - Heider, Andreas A1 - Scholz, Claus-Jürgen A1 - Cecil, Alexander A1 - Niesler, Beate A1 - Hirrlinger, Johannes A1 - Walles, Heike A1 - Metzger, Marco T1 - Activation of Myenteric Glia during Acute Inflammation In Vitro and In Vivo JF - PLoS One N2 - Background Enteric glial cells (EGCs) are the main constituent of the enteric nervous system and share similarities with astrocytes from the central nervous system including their reactivity to an inflammatory microenvironment. Previous studies on EGC pathophysiology have specifically focused on mucosal glia activation and its contribution to mucosal inflammatory processes observed in the gut of inflammatory bowel disease (IBD) patients. In contrast knowledge is scarce on intestinal inflammation not locally restricted to the mucosa but systemically affecting the intestine and its effect on the overall EGC network. Methods and Results In this study, we analyzed the biological effects of a systemic LPS-induced hyperinflammatory insult on overall EGCs in a rat model in vivo, mimicking the clinical situation of systemic inflammation response syndrome (SIRS). Tissues from small and large intestine were removed 4 hours after systemic LPS-injection and analyzed on transcript and protein level. Laser capture microdissection was performed to study plexus-specific gene expression alterations. Upon systemic LPS-injection in vivo we observed a rapid and dramatic activation of Glial Fibrillary Acidic Protein (GFAP)-expressing glia on mRNA level, locally restricted to the myenteric plexus. To study the specific role of the GFAP subpopulation, we established flow cytometry-purified primary glial cell cultures from GFAP promotor-driven EGFP reporter mice. After LPS stimulation, we analyzed cytokine secretion and global gene expression profiles, which were finally implemented in a bioinformatic comparative transcriptome analysis. Enriched GFAP+ glial cells cultured as gliospheres secreted increased levels of prominent inflammatory cytokines upon LPS stimulation. Additionally, a shift in myenteric glial gene expression profile was induced that predominantly affected genes associated with immune response. Conclusion and Significance Our findings identify the myenteric GFAP-expressing glial subpopulation as particularly susceptible and responsive to acute systemic inflammation of the gut wall and complement knowledge on glial involvement in mucosal inflammation of the intestine. KW - gene expression KW - gastrointestinal tract KW - inflammatory bowel disease KW - central nervous system KW - systemic inflammatory response syndrome KW - inflammation KW - astrocytes KW - cytokines Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-146544 VL - 11 IS - 3 ER -