@article{AlHejailanWeigelSchuerleinetal.2022, author = {Al-Hejailan, Reem and Weigel, Tobias and Sch{\"u}rlein, Sebastian and Berger, Constantin and Al-Mohanna, Futwan and Hansmann, Jan}, title = {Decellularization of full heart — optimizing the classical sodium-dodecyl-sulfate-based decellularization protocol}, series = {Bioengineering}, volume = {9}, journal = {Bioengineering}, number = {4}, issn = {2306-5354}, doi = {10.3390/bioengineering9040147}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-270781}, year = {2022}, abstract = {Compared to cell therapy, where cells are injected into a defect region, the treatment of heart infarction with cells seeded in a vascularized scaffold bears advantages, such as an immediate nutrient supply or a controllable and persistent localization of cells. For this purpose, decellularized native tissues are a preferable choice as they provide an in vivo-like microenvironment. However, the quality of such scaffolds strongly depends on the decellularization process. Therefore, two protocols based on sodium dodecyl sulfate or sodium deoxycholate were tailored and optimized for the decellularization of a porcine heart. The obtained scaffolds were tested for their applicability to generate vascularized cardiac patches. Decellularization with sodium dodecyl sulfate was found to be more suitable and resulted in scaffolds with a low amount of DNA, a highly preserved extracellular matrix composition, and structure shown by GAG quantification and immunohistochemistry. After seeding human endothelial cells into the vasculature, a coagulation assay demonstrated the functionality of the endothelial cells to minimize the clotting of blood. Human-induced pluripotent-stem-cell-derived cardiomyocytes in co-culture with fibroblasts and mesenchymal stem cells transferred the scaffold into a vascularized cardiac patch spontaneously contracting with a frequency of 25.61 ± 5.99 beats/min for over 16 weeks. The customized decellularization protocol based on sodium dodecyl sulfate renders a step towards a preclinical evaluation of the scaffolds.}, language = {en} } @phdthesis{ALHijailan2019, author = {AL-Hijailan, Reem Saud}, title = {Establishment of endothelialized cardiac tissue using human induced pluripotent stem cells generated cardiomyocytes}, doi = {10.25972/OPUS-17397}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-173979}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Cardiovascular diseases are considered the leading cause of death worldwide according to the World Health Organization. Heart failure is the last stage of most of these diseases, where loss of myocardium leads to architectural and functional decline. The definitive treatment option for patients with CVDs is organ or tissue transplantation, which relies on donor availability. Therefore, generating an autologous bioengineered myocardium or heart could overcome this limitation. In addition, generating cardiac patches will provide ventricular wall support and enable reparative stem cells delivery to damaged areas. Although many hurdles still exist, a good number of researches have attempted to create an engineered cardiac tissue which can induce endogenous cardiac repair by replacing damaged myocardium. The present study provided cardiac patches in two models, one by a detergent coronary perfusion decellularization protocol that was optimized, and the other that resulted in a 3D cell-free extracellular matrix with intact architecture and preserved s-glycosaminoglycan and vasculature conduits. Perfusion with 1\% Sodium dodecyle sulfate (SDS) under constant pressure resulted in cell-free porcine scaffold within two and cell-free rat scaffold in 7 days, whereas scaffold perfused with 4\% sodium deoxycholate (SDO) was not able to remove cells completely. Re-reendothelialization of tissue vasculature was obtained by injecting human microvascular endothelial cell and human fibroblast in 2:1 ratio in a dynamic culture. One-week later, CD31 positive cells and endothelium markers were observed, indicating new blood lining. Moreover, functionality test of re-endothelialized tissue revealed improvement in clotting seen in decellularized tissues. When the tissue was ready to be repopulated, porcine induced pluripotent stem cells (PiPSc) were generated by transfected reprogramming of porcine skin fibroblast and then differentiated to cardiac cells following a robust protocol, for an autologous cardiac tissue model. However, due to the limitation in the PiPSc cell number, alternatively, human induced pluripotent stem cells generated cardiac cells were used. For reseeding a coculture of human iPSc generated cardiac cells, human mesenchymal stem cells and human fibroblast in 2:1:1 ratio respectively were used in a dynamic culture for 6-8 weeks. Contractions at different areas of the tissue were recorded at an average beating rate of 67 beats/min. In addition, positive cardiac markers (Troponin T), Fibroblast (vemintin), and mesenchymal stem cells (CD90) were detected. Not only that, but by week 3, MSC started differentiating to cardiac cells progressively until few CD90 positive cells were very few by week 6 with increasing troponin t positive cells in parallel. Electrophysiological and drug studies were difficult to obtain due to tissue thickness and limited assessment sources. However, the same construct was established using small intestine submucosa (SISer) scaffold, which recorded a spontaneous beating rate between 0.88 and 1.2 Hz, a conduction velocity of 23.9 ± 0.74 cm s-1, and a maximal contraction force of 0.453 ± 0.015 mN. Moreover, electrophysiological studies demonstrated a drug-dependent response on beating rate; a higher adrenalin frequency was revealed in comparison to the untreated tissue and isoproterenol administration, whereas a decrease in beating rate was observed with propranolol and untreated tissue. The present study demonstrated the establishment of vascularized cardiac tissue, which can be used for human clinical application.}, language = {en} } @article{AlepeeBahinskiDaneshianetal.2014, author = {Alepee, Natalie and Bahinski, Anthony and Daneshian, Mardas and De Weyer, Bart and Fritsche, Ellen and Goldberg, Alan and Hansmann, Jan and Hartung, Thomas and Haycock, John and Hogberg, Helena T. and Hoelting, Lisa and Kelm, Jens M. and Kadereit, Suzanne and McVey, Emily and Landsiedel, Robert and Leist, Marcel and L{\"u}bberstedt, Marc and Noor, Fozia and Pellevoisin, Christian and Petersohn, Dirk and Pfannenbecker, Uwe and Reisinger, Kerstin and Ramirez, Tzutzuy and Rothen-Rutishauser, Barbara and Sch{\"a}fer-Korting, Monika and Zeilinger, Katrin and Zurich, Marie-Gabriele}, title = {State-of-the-Art of 3D Cultures (Organs-on-a-Chip) in Safety Testing and Pathophysiology}, series = {ALTEX - Alternatives to Animal Experimentation}, volume = {31}, journal = {ALTEX - Alternatives to Animal Experimentation}, number = {4}, doi = {2014; http://dx.doi.org/10.14573/altex1406111}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-117826}, pages = {441-477}, year = {2014}, abstract = {Integrated approaches using different in vitro methods in combination with bioinformatics can (i) increase the success rate and speed of drug development; (ii) improve the accuracy of toxicological risk assessment; and (iii) increase our understanding of disease. Three-dimensional (3D) cell culture models are important building blocks of this strategy which has emerged during the last years. The majority of these models are organotypic, i.e., they aim to reproduce major functions of an organ or organ system. This implies in many cases that more than one cell type forms the 3D structure, and often matrix elements play an important role. This review summarizes the state of the art concerning commonalities of the different models. For instance, the theory of mass transport/metabolite exchange in 3D systems and the special analytical requirements for test endpoints in organotypic cultures are discussed in detail. In the next part, 3D model systems for selected organs liver, lung, skin, brain are presented and characterized in dedicated chapters. Also, 3D approaches to the modeling of tumors are presented and discussed. All chapters give a historical background, illustrate the large variety of approaches, and highlight up- and downsides as well as specific requirements. Moreover, they refer to the application in disease modeling, drug discovery and safety assessment. Finally, consensus recommendations indicate a roadmap for the successful implementation of 3D models in routine screening. It is expected that the use of such models will accelerate progress by reducing error rates and wrong predictions from compound testing.}, language = {en} } @article{AlzheimerSvenssonKoenigetal.2020, author = {Alzheimer, Mona and Svensson, Sarah L. and K{\"o}nig, Fabian and Schweinlin, Matthias and Metzger, Marco and Walles, Heike and Sharma, Cynthia M.}, title = {A three-dimensional intestinal tissue model reveals factors and small regulatory RNAs important for colonization with Campylobacter jejuni}, series = {PLoS Pathogens}, volume = {16}, journal = {PLoS Pathogens}, number = {2}, doi = {10.1371/journal.ppat.1008304}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-229454}, year = {2020}, abstract = {The Gram-negative Epsilonproteobacterium Campylobacter jejuni is currently the most prevalent bacterial foodborne pathogen. Like for many other human pathogens, infection studies with C. jejuni mainly employ artificial animal or cell culture models that can be limited in their ability to reflect the in-vivo environment within the human host. Here, we report the development and application of a human three-dimensional (3D) infection model based on tissue engineering to study host-pathogen interactions. Our intestinal 3D tissue model is built on a decellularized extracellular matrix scaffold, which is reseeded with human Caco-2 cells. Dynamic culture conditions enable the formation of a polarized mucosal epithelial barrier reminiscent of the 3D microarchitecture of the human small intestine. Infection with C. jejuni demonstrates that the 3D tissue model can reveal isolate-dependent colonization and barrier disruption phenotypes accompanied by perturbed localization of cell-cell junctions. Pathogenesis-related phenotypes of C. jejuni mutant strains in the 3D model deviated from those obtained with 2D-monolayers, but recapitulated phenotypes previously observed in animal models. Moreover, we demonstrate the involvement of a small regulatory RNA pair, CJnc180/190, during infections and observe different phenotypes of CJnc180/190 mutant strains in 2D vs. 3D infection models. Hereby, the CJnc190 sRNA exerts its pathogenic influence, at least in part, via repression of PtmG, which is involved in flagellin modification. Our results suggest that the Caco-2 cell-based 3D tissue model is a valuable and biologically relevant tool between in-vitro and in-vivo infection models to study virulence of C. jejuni and other gastrointestinal pathogens.}, language = {en} } @article{AppeltMenzelCubukovaGuentheretal.2017, author = {Appelt-Menzel, Antje and Cubukova, Alevtina and G{\"u}nther, Katharina and Edenhofer, Frank and Piontek, J{\"o}rg and Krause, Gerd and St{\"u}ber, Tanja and Walles, Heike and Neuhaus, Winfried and Metzger, Marco}, title = {Establishment of a Human Blood-Brain Barrier Co-culture Model Mimicking the Neurovascular Unit Using Induced Pluri- and Multipotent Stem Cells}, series = {Stem Cell Reports}, volume = {8}, journal = {Stem Cell Reports}, number = {4}, doi = {10.1016/j.stemcr.2017.02.021}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170982}, pages = {894-906}, year = {2017}, abstract = {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.}, language = {en} } @article{Appelt‐MenzelOerterMathewetal.2020, author = {Appelt-Menzel, Antje and Oerter, Sabrina and Mathew, Sanjana and Haferkamp, Undine and Hartmann, Carla and Jung, Matthias and Neuhaus, Winfried and Pless, Ole}, title = {Human iPSC-Derived Blood-Brain Barrier Models: Valuable Tools for Preclinical Drug Discovery and Development?}, series = {Current Protocols in Stem Cell Biology}, volume = {55}, journal = {Current Protocols in Stem Cell Biology}, number = {1}, doi = {10.1002/cpsc.122}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-218509}, year = {2020}, abstract = {Translating basic biological knowledge into applications remains a key issue for effectively tackling neurodegenerative, neuroinflammatory, or neuroendocrine disorders. Efficient delivery of therapeutics across the neuroprotective blood-brain barrier (BBB) still poses a demanding challenge for drug development targeting central nervous system diseases. Validated in vitro models of the BBB could facilitate effective testing of drug candidates targeting the brain early in the drug discovery process during lead generation. We here review the potential of mono- or (isogenic) co-culture BBB models based on brain capillary endothelial cells (BCECs) derived from human-induced pluripotent stem cells (hiPSCs), and compare them to several available BBB in vitro models from primary human or non-human cells and to rodent in vivo models, as well as to classical and widely used barrier models [Caco-2, parallel artificial membrane permeability assay (PAMPA)]. In particular, we are discussing the features and predictivity of these models and how hiPSC-derived BBB models could impact future discovery and development of novel CNS-targeting therapeutics.}, language = {en} } @article{BasslerKnoblichGerhardHartmannetal.2023, author = {Bassler, Miriam C. and Knoblich, Mona and Gerhard-Hartmann, Elena and Mukherjee, Ashutosh and Youssef, Almoatazbellah and Hagen, Rudolf and Haug, Lukas and Goncalves, Miguel and Scherzad, Agmal and St{\"o}th, Manuel and Ostertag, Edwin and Steinke, Maria and Brecht, Marc and Hackenberg, Stephan and Meyer, Till Jasper}, title = {Differentiation of salivary gland and salivary gland tumor tissue via Raman imaging combined with multivariate data analysis}, series = {Diagnostics}, volume = {14}, journal = {Diagnostics}, number = {1}, issn = {2075-4418}, doi = {10.3390/diagnostics14010092}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-355558}, year = {2023}, abstract = {Salivary gland tumors (SGTs) are a relevant, highly diverse subgroup of head and neck tumors whose entity determination can be difficult. Confocal Raman imaging in combination with multivariate data analysis may possibly support their correct classification. For the analysis of the translational potential of Raman imaging in SGT determination, a multi-stage evaluation process is necessary. By measuring a sample set of Warthin tumor, pleomorphic adenoma and non-tumor salivary gland tissue, Raman data were obtained and a thorough Raman band analysis was performed. This evaluation revealed highly overlapping Raman patterns with only minor spectral differences. Consequently, a principal component analysis (PCA) was calculated and further combined with a discriminant analysis (DA) to enable the best possible distinction. The PCA-DA model was characterized by accuracy, sensitivity, selectivity and precision values above 90\% and validated by predicting model-unknown Raman spectra, of which 93\% were classified correctly. Thus, we state our PCA-DA to be suitable for parotid tumor and non-salivary salivary gland tissue discrimination and prediction. For evaluation of the translational potential, further validation steps are necessary.}, language = {en} } @article{BaurNietzerKunzetal.2020, author = {Baur, Florentin and Nietzer, Sarah L. and Kunz, Meik and Saal, Fabian and Jeromin, Julian and Matschos, Stephanie and Linnebacher, Michael and Walles, Heike and Dandekar, Thomas and Dandekar, Gudrun}, title = {Connecting cancer pathways to tumor engines: a stratification tool for colorectal cancer combining human in vitro tissue models with boolean in silico models}, series = {Cancers}, volume = {12}, journal = {Cancers}, number = {1}, issn = {2072-6694}, doi = {10.3390/cancers12010028}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-193798}, pages = {28}, year = {2020}, abstract = {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.}, language = {en} } @phdthesis{Baur2019, author = {Baur, Florentin Philipp}, title = {Establishment of a 3D tumour model and targeted therapy of BRAF-mutant colorectal cancer}, doi = {10.25972/OPUS-17412}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-174129}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Cancer remains after cardiovascular diseases the leading cause of death worldwide and an estimated 8.2 million people died of it in 2012. By 2030, 13 million cancer deaths are expected due to the growth and ageing of the population. Hereof, colorectal cancer (CRC) is the third most common cancer in men and the second in women with a wide geographical variation across the world. Usually, CRC begins as a non-cancerous growth leading to an adenomatous polyp, or adenoma, arising from glandular cells. Since research has brought about better understanding of the mechanisms of cancer development, novel treatments such as targeted therapy have emerged in the past decades. Despite that, up to 95\% of anticancer drugs tested in clinical phase I trials do not attain a market authorisation and hence these high attrition rates remain a key challenge for the pharmaceutical industry, making drug development processes enormously costly and inefficient. Therefore, new preclinical in vitro models which can predict drug responses in vivo more precisely are urgently needed. Tissue engineering not only provides the possibility of creating artificial three-dimensional (3D) in vitro tissues, such as functional organs, but also enables the investigation of drug responses in pathological tissue models, that is, in 3D cancer models which are superior to conventional two-dimensional (2D) cell cultures on petri dishes and can overcome the limitations of animal models, thereby reducing the need for preclinical in vivo models. In this thesis, novel 3D CRC models on the basis of a decellularised intestinal matrix were established. In the first part, it could be shown that the cell line SW480 exhibited different characteristics when grown in a 3D environment from those in conventional 2D culture. While the cells showed a mesenchymal phenotype in 2D culture, they displayed a more pronounced epithelial character in the 3D model. By adding stromal cells (fibroblasts), the cancer cells changed their growth pattern and built tumour-like structures together with the fibroblasts, thereby remodelling the natural mucosal structures of the scaffold. Additionally, the established 3D tumour model was used as a test system for treatment with standard chemotherapeutic 5-fluorouracil (5-FU). The second part of the thesis focused on the establishment of a 3D in vitro test system for targeted therapy. The US Food and Drug Administration has already approved of a number of drugs for targeted therapy of specific types of cancer. For instance, the small molecule vemurafenib (PLX4032, Zelboraf™) which demonstrated impressive response rates of 50-80\% in melanoma patients with a mutation of the rapidly accelerated fibrosarcoma oncogene type B (BRAF) kinase which belongs to the mitogen active protein kinase (MAPK) signalling pathway. However, only 5\% of CRC patients harbouring the same BRAF mutation respond to treatment with vemurafenib. An explanation for this unresponsiveness could be a feedback activation of the upstream EGFR, reactivating the MAPK pathway which sustains a proliferative signalling. To test this hypothesis, the two early passage cell lines HROC24 and HROC87, both presenting the mutation BRAF V600E but differing in other mutations, were used and their drug response to vemurafenib and/or gefitinib was assessed in conventional 2D cell culture and compared to the more advanced 3D model. Under 3D culture conditions, both cell lines showed a reduction of the proliferation rate only in the combination therapy approach. Furthermore, no significant differences between the various treatment approaches and the untreated control regarding apoptosis rate and viability for both cell lines could be found in the 3D tumour model which conferred an enhanced chemoresistance to the cancer cells. Because of the observed unresponsiveness to BRAF inhibition by vemurafenib as can be seen in the clinic for patients with BRAF mutations in CRC, the cell line HROC87 was used for further xenografting experiments and analysis of activation changes in the MAPK signalling pathway. It could be shown that the cells presented a reactivation of Akt in the 3D model when treated with both inhibitors, suggesting an escape mechanism for apoptosis which was not present in cells cultured under conventional 2D conditions. Moreover, the cells exhibited an activation of the hepatocyte growth factor receptor (HGFR, c-Met) in 2D and 3D culture, but this was not detectable in the xenograft model. This shows the limitations of in vivo models. The results suggest another feedback activation loop than that to the EGFR which might not primarily be involved in the resistance mechanism. This reflects the before mentioned high attrition rates in the preclinical drug testing.}, subject = {Dickdarmtumor}, language = {en} } @article{BelkaNickelKurth2019, author = {Belka, Janina and Nickel, Joachim and Kurth, Dirk G.}, title = {Growth on metallo-supramolecular coordination polyelectrolyte (MEPE) stimulates osteogenic differentiation of human osteosarcoma cells (MG63) and human bone marrow derived mesenchymal stem cells}, series = {Polymers}, volume = {11}, journal = {Polymers}, number = {7}, issn = {2073-4360}, doi = {10.3390/polym11071090}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-197264}, pages = {1090}, year = {2019}, abstract = {Background: Culturing of cells is typically performed on standard tissue culture plates generating growth conditions, which in general do not reflect the native three-dimensional cellular environment. Recent investigations provide insights in parameters, which strongly affect the general cellular behavior triggering essential processes such as cell differentiation. The physical properties of the used material, such as stiffness, roughness, or topology, as well as the chemical composition of the cell-surface interface are shown to play a key role in the initiation of particular cellular responses. Methods: We extended our previous research, which identified thin films of metallo-supramolecular coordination polyelectrolytes (MEPEs) as substrate to trigger the differentiation of muscular precursor cells. Results: Here, we show that the same MEPEs similarly stimulate the osteogenic differentiation of pre-osteoblasts. Remarkably, MEPE modified surfaces also trigger the differentiation of primary bone derived mesenchymal stem cells (BMSCs) towards the osteogenic lineage. Conclusion: This result leads to the conclusion that these surfaces individually support the specification of cell differentiation toward lineages that correspond to the natural commitment of the particular cell types. We, therefore, propose that Fe-MEPEs may be used as scaffold for the treatment of defects at least in muscular or bone tissue.}, language = {en} } @phdthesis{Berger2023, author = {Berger, Constantin}, title = {Influence of the pancreatic extracellular matrix on pancreatic differentiation of human induced pluripotent stem cells and establishment of 3D organ models}, doi = {10.25972/OPUS-24126}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-241268}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2023}, abstract = {Der Diabetes mellitus bezeichnet eine bislang unheilbare, metabolische Erkrankung, die mit schwerwiegenden Folgeerkrankungen einhergeht. Unter den potentiellen Strategien zur Heilung von Diabetes mellitus stellt die in vitro Generierung adulter β-Zellen des endokrinen Pankreas aus humanen induziert pluripotenten Stammzellen (hiPS) einen vielversprechenden Ansatz dar. Zwar erm{\"o}glichen bisherige Protokolle die Herstellung von Zellen mit einem β-Zell-{\"a}hnlichen Charakter, jedoch zeigen diese eine zun{\"a}chst eingeschr{\"a}nkte Funktion, die sich erst im Verlauf einer vollst{\"a}ndigen, durch Transplantation induzierten, Reifung der Zellen, normalisiert. Vorangegangene Studien zeigen, dass sich die Extrazellularmatrix (EZM) von Geweben positiv auf das {\"U}berleben und die Funktion adulter, isolierter Langerhans-Inseln des Pankreas auswirkt. Vor diesem Hintergrund stellt sich die Frage, ob Einfl{\"u}sse der organspezifischen EZM die finale Reifung in vitro hergestellter β-Zellen herbeif{\"u}hren k{\"o}nnen. Um diese Hypothese zu testen, wurde im Rahmen der vorliegenden Studie die Wirkung der pankreatischen EZM auf die in vitro Differenzierung von hiPS zu endokrinen Zellen des Pankreas untersucht sowie die Eignung der pankreatischen EZM zur Etablierung eines Organmodells des endokrinen Pankreas erprobt. Hierzu wurde zun{\"a}chst eine pankreasspezifische EZM-Tr{\"a}gerstruktur (PanMa) durch Dezellularisierung von Pankreaten des Schweins mittels Natriumdesoxycholat hergestellt. Die generierte PanMa wurde anhand (immun-) histologischer F{\"a}rbungen, Rasterelektronen-mikroskopie, Feststellung des DNA-Gehalts sowie durch Versuche zur Perfusion und Wiederbesiedelung mit Endothelzellen eingehend charakterisiert. Zudem wurde auf Basis der ermittelten Daten ein Bewertungssystem (PancScore) zur standardisierten Herstellung der PanMa entwickelt. Als N{\"a}chstes wurde untersucht, ob die PanMa {\"u}ber gewebespezifische EZM-Merkmale verf{\"u}gt. Zu diesem Zweck wurden biophysikalische und strukturelle Eigenschaften wie Festigkeit, Porosit{\"a}t und Hygroskopie mittels rheologischer Messungen sowie Versuchen zur Teilchendiffusion und zum Wasserbindungsverhalten bestimmt und mit azellul{\"a}ren EZMs des D{\"u}nndarms (SISser) und der Lunge (LungMa) verglichen. Nach der eingehenden Analyse der PanMa wurde deren Effekt auf die Eigenschaften von Stammzellen sowie auf fr{\"u}he Stadien der Stammzellentwicklung untersucht. Hierzu wurde die PanMa als Tr{\"a}gerstruktur w{\"a}hrend der Erhaltung sowie der spontanen Differenzierung von hiPS verwendet und der Einfluss der PanMa anhand von Genexpressionsanalysen und immunhistochemischer F{\"a}rbungen analysiert. In einem n{\"a}chsten Schritt wurde die Wirkung der PanMa auf die Differenzierung von hiPS zu endokrinen Zellen des Pankreas untersucht. Hierf{\"u}r wurde die PanMa zum einen in fl{\"u}ssiger Form als Mediumzusatz sowie als solide Tr{\"a}gerstruktur w{\"a}hrend der Differenzierung von hiPS zu hormonexprimierenden Zellen (Rezania et al. 2012; Rezania et al. 2014) oder maturierenden β-Zellen verwendet (Rezania et al. 2014). Der Effekt der PanMa wurde anhand von Genexpressions-analysen, immunhistochemischer F{\"a}rbungen und Analysen zur Glukose-abh{\"a}ngigen Insulinsekretion untersucht. In einem letzten Teil der Studie wurde die Eignung der PanMa zur verl{\"a}ngerten Kultivierung von hiPS-abgeleiteten endokrinen Zellen des Pankreas im Hinblick auf die Etablierung eines Organmodells des endokrinen Pankreas getestet. Hierzu wurde die PanMa zu einem Hydrogel weiterverarbeitet, welches zur Einkapselung und Kultivierung von hiPS-abgeleiteten hormonexprimierenden Zellen eingesetzt wurde. Um die Auswirkungen der Hydrogel-Kultur nachzuvollziehen, wurden die kultivierten Zellen mittels Genexpression, immun-histochemischer F{\"a}rbungen und Analysen zur Glukose-abh{\"a}ngigen Insulinsekretion untersucht. Mittels Dezellularisierung porziner Pankreaten konnte eine zellfreie, pankreasspezifische EZM-Tr{\"a}gerstruktur mit geringen Restbest{\"a}nden an DNA sowie einer weitgehend erhaltenen Mikro- und Ultrastruktur mit typischen EZM-Komponenten wie Kollagen I, III und IV hergestellt werden. Im Rahmen der Besiedelung arterieller Gef{\"a}ße mit humanen Endothelzellen wurde die Zellkompatibilit{\"a}t der hergestellten PanMa sowie eine weitgehende Unversehrtheit der Gef{\"a}ßstrukturen nachgewiesen. Verglichen zu SISser und LungMa zeichnete sich die PanMa als eine relativ weiche, stark wasserbindende, faserbasierte Struktur aus. Weiterhin konnten Hinweise f{\"u}r einen Effekt der PanMa auf den Stammzellcharakter und die fr{\"u}he Entwicklung von hiPS beobachtet werden. Hierbei f{\"u}hrte die Erhaltung von hiPS auf der PanMa zu einer leicht ver{\"a}nderten Expression von Genen des Kernpluripotenznetzwerks sowie zu einem reduziertem NANOG-Proteinsignal. Einhergehend mit diesen Beobachtungen zeigten hiPS w{\"a}hrend spontaner Differenzierung auf der PanMa eine verst{\"a}rkte endodermale Entwicklung. Im Verlauf der pankreatischen Differenzierung f{\"u}hrte die Kultivierung auf der PanMa zu einer signifikant verringerten Expression von Glukagon und Somatostatin, w{\"a}hrend die Expression von Insulin unver{\"a}ndert blieb, was auf eine Verminderung endokriner α- und δ-Zellen hinweist. Diese Ver{\"a}nderung {\"a}ußerte sich jedoch nicht in einer verbesserten Glukose-abh{\"a}ngigen Insulinsekretion der generierten hormonexprimierenden Zellen. Unter Anwendung der PanMa als Hydrogel konnten hormonexprimierenden Zellen {\"u}ber einen verl{\"a}ngerten Zeitraum kultiviert werden. Nach 21 Tagen in Kultur zeigten die eingekapselten hormonexprimierenden Zellen eine unver{\"a}ndert hohe Viabilit{\"a}t, wiesen allerdings bereits eine erste ver{\"a}nderte Zellanordnung sowie eine leicht verminderte Glukose-abh{\"a}ngige Insulinsekretion auf. Zusammengefasst konnte in dieser Studie ein biologischer Effekt gewebespezifischer EZM-Merkmale auf die Differenzierung von hiPS nachgewiesen werden. Dar{\"u}ber hinaus weisen die Daten auf eine relevante Funktion der EZM im Rahmen der endokrinen Spezifizierung von hiPS w{\"a}hrend der pankreatischen Differenzierung hin. Diese Beobachtungen verdeutlichen die eminente Rolle der EZM in der Herstellung von funktionalen hiPS-abgeleiteten Zellen und pl{\"a}dieren f{\"u}r eine st{\"a}rkere Einbindung organspezifischer EZMs im Bereich des Tissue Engineering und der klinischen Translation in der Regenerativen Medizin.}, subject = {Bauchspeicheldr{\"u}se}, language = {en} } @article{BergerZdzieblo2020, author = {Berger, Constantin and Zdzieblo, Daniela}, title = {Glucose transporters in pancreatic islets}, series = {Pfl{\"u}gers Archiv - European Journal of Physiology}, volume = {472}, journal = {Pfl{\"u}gers Archiv - European Journal of Physiology}, issn = {0031-6768}, doi = {10.1007/s00424-020-02383-4}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-232738}, pages = {1249-1272}, year = {2020}, abstract = {The fine-tuning of glucose uptake mechanisms is rendered by various glucose transporters with distinct transportcharacteristics. In the pancreatic islet, facilitative diffusion glucose transporters (GLUTs), and sodium-glucosecotransporters (SGLTs) contribute to glucose uptake and represent important components in the glucose-stimulatedhormone release from endocrine cells, therefore playing a crucial role in blood glucose homeostasis. This reviewsummarizes the current knowledge aboutcell type-specific expression profiles as well as proven and putative functionsof distinct GLUT and SGLT family members in the human and rodent pancreatic islet and further discusses their possibleinvolvement in onset and progression ofdiabetes mellitus. In context of GLUTs, we focus on GLUT2, characterizing themain glucose transporter in insulin-secretingβ-cells in rodents. In addition, we discuss recent data proposing that otherGLUT family members, namely GLUT1 and GLUT3, render this task in humans. Finally, we summarize latest infor-mation about SGLT1 and SGLT2 as representatives of the SGLT family that have been reported to be expressed predominantly in the α-cell population with a suggested functional role in the regulation of glucagon release}, language = {en} } @phdthesis{Berninger2014, author = {Berninger, Ann-Kathrin}, title = {In-vitro-Untersuchungen zur Biokompatibilit{\"a}t modifizierter Silikonoberfl{\"a}chen}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-113911}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2014}, abstract = {Hintergrund Jede Implantation alloplastischer Materialien f{\"u}hrt durch Aktivierung der k{\"o}rpereigenen Immunabwehr zu einer Fremdk{\"o}rperreaktion. An der Synthese der Extrazellul{\"a}rmatrix und der entstehenden Kollagenkapsel sind insbesondere Makrophagen und Fibroblasten beteiligt. Diese Reaktionen k{\"o}nnen die Material-Funktionsf{\"a}higkeit abschw{\"a}chen, aufheben oder zu deren operativer Entfernung zwingen. Fragestellung und Ziele Spinnenseide ist ein Material mit hoher Biokompatibilit{\"a}t. Nachdem es gelungen ist, Spinnenseide rekombinant herzustellen, soll untersucht werden, wie sich die Vertr{\"a}glichkeit alloplastischer Materialien durch eine Beschichtung mit biotechnologisch hergestellter Spinnenseide beeinflussen l{\"a}sst. Eine weitere M{\"o}glichkeit ist der TGF-β-Synthese-Inhibitor Halofuginon, der ebenfalls hinsichtlich seiner Potenz, die Ausbildung einer Fibrosekapsel zu vermindern, untersucht werden soll. Methodik Anhand von in-vitro-Untersuchungen wurden die bei der Fremdk{\"o}rperreaktion beteiligten Zelltypen auf ihr Proliferationsverhalten und die Expression unterschiedlicher Genprodukte hinsichtlich bestehender Unterschiede zwischen den jeweiligen Oberfl{\"a}chenbeschichtungen untersucht. Es wurden immunhistochemische F{\"a}rbungen zum Nachweis spezifischer Oberfl{\"a}chenantigene, Bestimmungen von ATP- und DNA-Gehalt als Maß f{\"u}r die Zellzahl, sowie molekulargenetische Untersuchungen hinsichtlich der Expression relevanter Markergene (rtPCR) durchgef{\"u}hrt. Ergebnisse Eine Beschichtung mit rekombinanter Spinnseide f{\"u}hrt - im Vergleich zu reinen Silikonimplantaten - zu einer verz{\"o}gerten und reduzierten Immunreaktion. Die EZM-Synthese und die damit verbundene fremdk{\"o}rperassoziierte Fibrose werden vermindert und so die Biokompatibilit{\"a}t alloplastischer Materialien gesteigert.}, subject = {Fibrose}, language = {de} } @phdthesis{Bersi2017, author = {Bersi, Heidi}, title = {Etablierung eines 3D in vitro Blutgef{\"a}ß-/Gewebemodells zur Testung spezifischer Therapeutika zur Leuk{\"a}miebehandlung}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-152506}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2017}, abstract = {In Deutschland erkranken j{\"a}hrlich etwa 500.000 Menschen an Krebs, wovon circa 12.000 die Diagnose „Leuk{\"a}mie" gestellt bekommen [1]. Unter den Leuk{\"a}mien weist die akute myeloische Leuk{\"a}mie (AML) die ung{\"u}nstigste Prognose auf, sodass hier erheblicher Forschungsbedarf besteht. Zus{\"a}tzlich schnitten viele potentielle Therapeutika, die sich in bisherigen pr{\"a}klinischen Testsystemen als vielversprechend erwiesen haben, in klinischen Studien schlecht ab [8]. Ziel dieser Arbeit war daher die Etablierung eines 3D in vitro Blutgef{\"a}ß-/Gewebemodells als verbessertes pr{\"a}klinisches System zur Testung von Therapeutika, die zur erfolgreichen Behandlung von Leuk{\"a}mien beitragen sollen. Das 3D Blutgef{\"a}ßmodell bestand aus humanen prim{\"a}ren Endothelzellen, welche als Monolayer auf der Serosaseite einer dezellularisierten, porzinen, intestinalen Kollagenmatrix (SIS-Ser) wuchsen. Nach 14-t{\"a}giger Zellkultur wurden dem Versuchsansatz entsprechend nichtadh{\"a}rente THP-1 Zellen (AML-M5-Zelllinie) und Tipifarnib oder entsprechende Kontrolll{\"o}sungen beziehungsweise bimolekulare Antik{\"o}rperkonstrukte mit PBMCs als Effektorzellen hinzupipettiert. Nach 5-t{\"a}giger Inkubation mit Tipifarnib beziehungsweise 24-st{\"u}ndiger Behandlung mit Antik{\"o}rperkonstrukten wurde der therapiebedingte Anstieg der Apoptoserate in den malignen THP-1 Zellen mittels durchflusszytometrischer Analyse der Modell{\"u}berst{\"a}nde ermittelt. Zum Ausschluss verbliebener und durchflusszytometrisch zu analysierender Zellen wurde, stellvertretend f{\"u}r alle Suspensionszellen, eine Anti-CD13/DAB-F{\"a}rbung durchgef{\"u}hrt, welche negativ ausfiel. M{\"o}gliche Kollateralsch{\"a}den am Endothel wurden mittels histologischen F{\"a}rbemethoden an Gewebeparaffinschnitten untersucht. In der Durchflusszytometrie zeigte Tipifarnib sowohl im 2D als auch im 3D Modell {\"a}quivalente, dosisabh{\"a}ngige und antileuk{\"a}mische Auswirkungen auf die THP-1 Zellen. Bei Applikation der Antik{\"o}rperkonstrukte ließ lediglich die Kombination beider Hemibodies signifikante Effekte auf die THP-1 Zellen erkennen. Dabei zeigten sich bei konstanten Konzentrationen der Antik{\"o}rperkonstrukte im 3D Modell deutlich h{\"o}here Apoptoseraten (58\%) als im 2D Modell (38\%). Stellt man Vergleiche von Tipifarnib mit den T-Zell-rekrutierenden Antik{\"o}rperkonstrukten an, so ließen sich im 2D Modell {\"a}hnliche Apoptoseraten in den THP-1 Zellen erzielen (jeweils 38\% bei Anwendung von 500 nM Tipifarnib). In den 3D Modellen erzielten jedoch die niedriger konzentrierten Antik{\"o}rperkonstrukte bei k{\"u}rzerer Inkubationsdauer eine noch h{\"o}here spezifische Apoptoserate in den THP-1 Zellen (im Mittel 58\%) als 500 nM Tipifarnib (mittlere Apoptoserate 40\%). Bez{\"u}glich der Nebenwirkungen ließ sich im 3D Modell nach Applikation von Antik{\"o}rperkonstrukten kein wesentlicher Einfluss auf das Endothel erkennen, w{\"a}hrend Tipifarnib/DMSO als auch die mit DMSO versetzten Kontrolll{\"o}sungen zu einer dosisabh{\"a}nigen Destruktion des urspr{\"u}nglichen Endothelzellmonolayers f{\"u}hrten. Damit stellt die hier beschriebene, hoch spezifische, Hemibody-vermittelte Immuntherapie einen vielversprechenden Ansatz f{\"u}r zuk{\"u}nftige onkologische Therapien dar. Mithilfe des etablierten humanen 3D in vitro Modells konnte im Vergleich zur konventionellen Zellkultur eine nat{\"u}rlichere Mikroumgebung f{\"u}r Zellen geschaffen und die Auswirkungen der Testsubstanzen sowohl auf maligne Zellen, als auch auf die Gef{\"a}ßstrukturen untersucht werden.}, subject = {Tissue Engineering}, language = {de} } @article{BianchiSivarajanWallesetal.2021, author = {Bianchi, Maria and Sivarajan, Rinu and Walles, Thorsten and Hackenberg, Stephan and Steinke, Maria}, title = {Susceptibility of primary human airway epithelial cells to Bordetella pertussis adenylate cyclase toxin in two- and three-dimensional culture conditions}, series = {Innate Immunity}, volume = {27}, journal = {Innate Immunity}, number = {1}, issn = {1753-4259}, doi = {10.1177/1753425920979354}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-219849}, pages = {89-98}, year = {2021}, abstract = {The human pathogen Bordetella pertussis targets the respiratory epithelium and causes whooping cough. Its virulence factor adenylate cyclase toxin (CyaA) plays an important role in the course of infection. Previous studies on the impact of CyaA on human epithelial cells have been carried out using cell lines derived from the airways or the intestinal tract. Here, we investigated the interaction of CyaA and its enzymatically inactive but fully pore-forming toxoid CyaA-AC- with primary human airway epithelial cells (hAEC) derived from different anatomical sites (nose and tracheo-bronchial region) in two-dimensional culture conditions. To assess possible differences between the response of primary hAEC and respiratory cell lines directly, we included HBEC3-KT in our studies. In comparative analyses, we studied the impact of both the toxin and the toxoid on cell viability, intracellular cAMP concentration and IL-6 secretion. We found that the selected hAEC, which lack CD11b, were differentially susceptible to both CyaA and CyaA-AC-. HBEC3-KT appeared not to be suitable for subsequent analyses. Since the nasal epithelium first gets in contact with airborne pathogens, we further studied the effect of CyaA and its toxoid on the innate immunity of three-dimensional tissue models of the human nasal mucosa. The present study reveals first insights in toxin-cell interaction using primary hAEC.}, language = {en} } @article{BingShiTanKressCastroetal.2013, author = {Bing-Shi Tan, Ariel and Kress, Sebastian and Castro, Leticia and Sheppard, Allan and Raghunath, Michael}, title = {Cellular re- and de-programming by microenvironmental memory: why short TGF-β1 pulses can have long effects}, series = {Fibrogenesis Tissue Repair}, volume = {6}, journal = {Fibrogenesis Tissue Repair}, number = {12}, doi = {10.1186/1755-1536-6-12}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-131898}, year = {2013}, abstract = {Background Fibrosis poses a substantial setback in regenerative medicine. Histopathologically, fibrosis is an excessive accumulation of collagen affected by myofibroblasts and this can occur in any tissue that is exposed to chronic injury or insult. Transforming growth factor (TGF)-β1, a crucial mediator of fibrosis, drives differentiation of fibroblasts into myofibroblasts. These cells exhibit α-smooth muscle actin (α-SMA) and synthesize high amounts of collagen I, the major extracellular matrix (ECM) component of fibrosis. While hormones stimulate cells in a pulsatile manner, little is known about cellular response kinetics upon growth factor impact. We therefore studied the effects of short TGF-β1 pulses in terms of the induction and maintenance of the myofibroblast phenotype. Results Twenty-four hours after a single 30 min TGF-β1 pulse, transcription of fibrogenic genes was upregulated, but subsided 7 days later. In parallel, collagen I secretion rate and α-SMA presence were elevated for 7 days. A second pulse 24 h later extended the duration of effects to 14 days. We could not establish epigenetic changes on fibrogenic target genes to explain the long-lasting effects. However, ECM deposited under singly pulsed TGF-β1 was able to induce myofibroblast features in previously untreated fibroblasts. Dependent on the age of the ECM (1 day versus 7 days' formation time), this property was diminished. Vice versa, myofibroblasts were cultured on fibroblast ECM and cells observed to express reduced (in comparison with myofibroblasts) levels of collagen I. Conclusions We demonstrated that short TGF-β1 pulses can exert long-lasting effects on fibroblasts by changing their microenvironment, thus leaving an imprint and creating a reciprocal feed-back loop. Therefore, the ECM might act as mid-term memory for pathobiochemical events. We would expect this microenvironmental memory to be dependent on matrix turnover and, as such, to be erasable. Our findings contribute to the current understanding of fibroblast induction and maintenance, and have bearing on the development of antifibrotic drugs.}, language = {en} } @phdthesis{Bittorf2021, author = {Bittorf, Patrick}, title = {Entwicklung, Herstellung und pr{\"a}klinisches Studienprogramm f{\"u}r ein Arzneimittel f{\"u}r neuartige Therapien zur Behandlung der schweren Form der H{\"a}mophilie A}, doi = {10.25972/OPUS-23185}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-231858}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2021}, abstract = {Bevor ein zellbasiertes GTMP erstmalig beim Menschen angewendet werden kann, m{\"u}ssen verschiedene notwendige nicht-klinische Studien durchgef{\"u}hrt werden. Wichtig ist hier u.a. die Untersuchung der Biodistribution im Tiermodel. Diese umfasst die Verteilung, das Engraftment, die Persistenz, die Eliminierung und gegebenenfalls die Expansion der humanen Zellen in verschiedenen Organen, meistens im Mausmodel. Deshalb wurde eine qPCR-basierte Analysenmethode entwickelt, mit der humane genomische DNA innerhalb von muriner genomischer DNA bestimmt werden kann, und entsprechend den regulatorischen Richtlinien der European Medicines Agency und des International Council for Harmonisation validiert. Anschließend wurde diese Methode innerhalb einer pr{\"a}klinischen worst-case Szenario Biodistributionsstudie angewendet. Das Ziel dieser Studie war die Untersuchung des Biodistributionsprofils von genetisch modifizierten Blood Outgrowth Endothelial Cells von H{\"a}mophilie A Patienten 24 Stunden und sieben Tage nach intraven{\"o}ser Applikation einer Dosis von 2x106 Zellen. Die Isolation, genetische Modifikation und die Expansion der Zellen sollte entsprechend den Richtlinien der Guten Herstellungspraxis durchgef{\"u}hrt werden. Hierbei ist die Auswahl und Anwendung geeigneter und essentieller Rohstoffe wichtig. Gleichermaßen ist die Durchf{\"u}hrung einer definierten Qualit{\"a}tskontrollstrategie notwendig und die Patientenzellen sollten nur innerhalb von nicht-klinischen Studien eingesetzt werden, wenn alle Akzeptanzkriterien erf{\"u}llt wurden. Die Validierung der qPCR-Methode zeigte eine hohe Genauigkeit, Pr{\"a}zision und Linearit{\"a}t innerhalb des Konzentrationsintervalls von 1:1x103 bis 1:1x106 humanen zu murinen Genomen. Bei Anwendung dieser Methode f{\"u}r die Biodistributionsstudie konnten nach 24 Stunden humane Genome in vier der acht untersuchten Mausorgane bestimmt werden. Nach sieben Tagen konnten in keinem der acht Organe humane Genome nachgewiesen werden...}, subject = {Arzneimittel}, language = {de} } @article{BittorfBergmannMerlinetal.2020, author = {Bittorf, Patrick and Bergmann, Thorsten and Merlin, Simone and Olgasi, Chistina and Pullig, Oliver and Sanzenbacher, Ralf and Zierau, Martin and Walles, Heike and Follenzi, Antonia and Braspenning, Joris}, title = {Regulatory-Compliant Validation of a Highly Sensitive qPCR for Biodistribution Assessment of Hemophilia A Patient Cells}, series = {Molecular Therapy - Methods \& Clinical Development}, volume = {18}, journal = {Molecular Therapy - Methods \& Clinical Development}, doi = {10.1016/j.omtm.2020.05.029}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-230284}, pages = {176-188}, year = {2020}, abstract = {The investigation of the biodistribution profile of a cell-based medicinal product is a pivotal prerequisite to allow a factual benefit-risk assessment within the non-clinical to clinical translation in product development. Here, a qPCR-based method to determine the amount of human DNA in mouse DNA was validated according to the guidelines of the European Medicines Agency and the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use. Furthermore, a preclinical worst-case scenario study was performed in which this method was applied to investigate the biodistribution of 2 x 10\(^6\) intravenously administered, genetically modified, blood outgrowth endothelial cells from hemophilia A patients after 24 h and 7 days. The validation of the qPCR method demonstrated high accuracy, precision, and linearity for the concentration interval of 1:1 x 10\(^3\) to 1:1 x 10\(^6\) human to mouse DNA. The application of this method in the biodistribution study resulted in the detection of human genomes in four out of the eight investigated organs after 24 h. After 7 days, no human DNA was detected in the eight organs analyzed. This biodistribution study provides mandatory data on the toxicokinetic safety profile of an actual candidate cell-based medicinal product. The extensive evaluation of the required validation parameters confirms the applicability of the qPCR method for non-clinical biodistribution studies.}, language = {en} } @phdthesis{Bleuel2021, author = {Bleuel, Gabriel}, title = {Entwicklung und Validierung eines quantitativen Verfahrens zur Beurteilung der Viabilit{\"a}t von entsprechend der GMP-Richtlinien hergestellter Knorpelimplantate f{\"u}r das Knie}, doi = {10.25972/OPUS-24248}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-242481}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2021}, abstract = {Due to the reversing age pyramid in Germany, more and more people are already suffering from joint cartilage damage. But not only age, but also accidents and sports injuries and being overweight can lead to irreversible cartilage defects. Although there are various treatment options, the previous methods cannot be considered a permanent cure. As part of the international research project BIO-CHIP, a promising treatment method with novel drugs was to be investigated. The patient's own cartilage cells from the nose serve as the starting material for the drug, a manufactured cartilage implant. These are isolated, multiplied and ultimately cultivated on a matrix to form a cartilage implant. In addition to toxicological and biological safety tests, an essential prerequisite for the approval of the implant is the assessment of the viability. This was previously carried out on the basis of histology from the pathology department. The aim of the present work was the development and validation of a standardized and objective viability test for the chondrocytes within the cartilage matrix. For this, the LDH was used as a marker for irreversibly damaged cells. The LDH concentration could be measured with the CyQuant LDH assay by measuring the absorption. It could be proven that LDH has the required stability and detectability in the medium. With the help of the lysis, of cultivated mini-cartilage implants, the maximum achievable LDH concentrations could be determined. A calibration curve was generated using these concentrations. This serves to assess the viability of future measured absorptions of the supernatant medium. The developed method does not require any invasive interventions on the implant and is characterized by its simple implementation, since only the protrusion has to be measured. The validation of the method certified a high level of robustness, linearity, accuracy and precision.}, subject = {Hyaliner Knorpel}, language = {de} } @article{BorovaSchluttNickeletal.2022, author = {Borova, Solomiia and Schlutt, Christine and Nickel, Joachim and Luxenhofer, Robert}, title = {A Transient Initiator for Polypeptoids Postpolymerization α-Functionalization via Activation of a Thioester Group}, series = {Macromolecular Chemistry and Physics}, volume = {223}, journal = {Macromolecular Chemistry and Physics}, number = {3}, doi = {10.1002/macp.202100331}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-257587}, year = {2022}, abstract = {Here, a postpolymerization modification method for an α-terminal functionalized poly-(N-methyl-glycine), also known as polysarcosine, is introduced. 4-(Methylthio)phenyl piperidine-4-carboxylate as an initiator for the ring-opening polymerization of N-methyl-glycine-N-carboxyanhydride followed by oxidation of the thioester group to yield an α-terminal reactive 4-(methylsulfonyl)phenyl piperidine-4-carboxylate polymer is utilized. This represents an activated carboxylic acid terminus, allowing straightforward modification with nucleophiles under mild reaction conditions and provides the possibility to introduce a wide variety of nucleophiles as exemplified using small molecules, fluorescent dyes, and model proteins. The new initiator yielded polymers with well-defined molar mass, low dispersity, and high end-group fidelity, as observed by gel permeation chromatography, nuclear magnetic resonance spectroscopy, and matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy. The introduced method can be of great interest for bioconjugation, but requires optimization, especially for protein conjugation.}, language = {en} }