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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). Suspension cul- tures of hiPSCs are characterized by the self-aggregation of single cells into macroscopic cell aggre- gates that increase in size over time. The development of these free-floating aggregates is dependent on the culture vessel and thus represents a novel process parameter that is of particular interest for hiPSC suspension culture scaling. Further, aggregates surpassing a critical size are prone to spon- taneous differentiation or cell viability loss. In this regard, and, for the first time, a hiPSC-specific suspension culture unit was developed that utilizes in situ microscope imaging to monitor and to characterize hiPSC aggregation in one specific CSTR setup to a statistically significant degree while omitting the need for error-prone and time-intensive sampling. For this purpose, a small-scale CSTR system was designed and fabricated by fused deposition modeling (FDM) using an in-house 3D- printer. To provide a suitable cell culture environment for the CSTR system and in situ microscope, a custom-built incubator was constructed to accommodate all culture vessels and process control devices. Prior to manufacture, the CSTR design was characterized in silico for standard engineering parameters such as the specific power input, mixing time, and shear stress using computational fluid dynamics (CFD) simulations. The established computational model was successfully validated by comparing CFD-derived mixing time data to manual measurements. Proof for system functionality was provided in the context of long-term expansion (4 passages) of hiPSCs. Thereby, hiPSC aggregate size development was successfully tracked by in situ imaging of CSTR suspensions and subsequent automated image processing. Further, the suitability of the developed hiPSC culture unit was proven by demonstrating the preservation of CSTR-cultured hiPSC pluripotency on RNA level by qRT-PCR and PluriTest, and on protein level by flow cytometry.
Die Einhaltung eines gesunden Lebensstils, einschließlich der Behandlung modifizierbarer kardiovaskulärer Risikofaktoren, beeinflusst maßgeblich die Entstehung und Progression von Herz-Kreislauf-Erkrankungen (HKE). So reduziert eine ausgewogene Ernährungsweise, ausreichend körperliche Aktivität, Tabakverzicht, das Halten des Normalgewichtes sowie die Behandlung einer Hypertonie, Hyperlipidämie und Diabetes mellitus, die kardiovaskuläre Morbidität und Mortalität.
Die vorliegende Arbeit widmet sich (a) der Prävalenz und leitliniengerechten Kontrolle kardiovaskulärer Risikofaktoren von Teilnehmern aus der Allgemeinbevölkerung der STAAB Kohortenstudie („Häufigkeit und Einflussfaktoren auf frühe Stadien A und B der Herzinsuffizienz in der Bevölkerung“) sowie der Schätzung des 10-Jahres Risikos für tödliche HKE in diesem Kollektiv. Weiterhin wurde (b) der Einfluss von medikamentenbezogenen Überzeugungen auf die Blutdruckkontrolle von Teilnehmern der STAAB Kohortenstudie untersucht. Schließlich wurde (c) der Erhalt von ärztlichen Lebensstilempfehlungen sowie deren Determinanten bei Teilnehmern der STAAB Kohortenstudie sowie der EUROASPIRE IV Studie („European Action on Secondary and Primary Prevention by Intervention to Reduce
Events“) in Deutschland betrachtet.
Die STAAB Kohortenstudie untersucht die frühen asymptomatischen Formen der Herzinsuffizienz-Stadien A und B in einer repräsentativen Stichprobe von 5.000 Personen
ohne symptomatische Herzinsuffizienz im Alter von 30 bis 79 Jahren aus der Allgemeinbevölkerung mit Wohnsitz in der Stadt Würzburg.
Die EUROASPIRE IV Studie untersuchte bei 7.998 Koronarpatienten im Alter von 18 bis 79
Jahren aus insgesamt 24 Europäischen Ländern (536 Patienten aus Deutschland) im Zeitraum 2012 bis 2013 die Risikofaktoren sowie die Umsetzung der leitliniengerechten Versorgung und Prävention von HKE im europäischen Vergleich. Die Datenerhebung beider Studien erfolgte durch ein geschultes Studienpersonal nach standardisierten Vorgaben.
Die Prävalenz und Kontrolle kardiovaskulärer Risikofaktoren nach den aktuellen Vorgaben der „European Society of Cardiology“ (ESC) wurde bei insgesamt 1.379 Teilnehmern, die zwischen Dezember 2013 und April 2015 an der STAAB Kohortenstudie teilgenommen haben, untersucht. Es zeigte sich eine hohe Prävalenz der kardiovaskulären Risikofaktoren Hypertonie (31.8%), Hyperlipidämie (57.6%) und Diabetes mellitus (3.5%). Hierbei erreichten
trotz Pharmakotherapie über die Hälfte der Teilnehmer mit einem Bluthochdruck (52.7%) oder erhöhten LDL-Cholesterinwerten (56.7%) sowie 44.0% der Personen mit einem Diabetes mellitus die empfohlenen Grenzwerte nicht. Weiterhin wurde erstmalig zu Studienbesuch eine Hypertonie (36.0%), Hyperlipidämie (54.2%) oder ein Langzeitzuckerwert (HbA1c) >6.5% (23.3%) detektiert. In der jüngsten Altersgruppe (30-39 Jahre) fand sich der höchste Anteil von unbekanntem Bluthochdruck (76.5%) sowie hohem LDL-Cholesterin (78.0%) und die Altersgruppe 60-69 Jahren wies mit 43.5% die höchste Prävalenz für einen bislang nicht detektierten HbA1c >6.5% auf. Die Akkumulation von drei oder mehr kardiovaskulären Risikofaktoren war mit dem männlichen Geschlecht, einem höheren Alter und einem niedrigeren Bildungsgrad assoziiert. Von 980 mittels SCORE („Systematic Coronary Risk Evaluation“) Risiko-Chart untersuchten Teilnehmern befanden sich jeweils 56.6%, 35.8% und 7.5% in der niedrigen, mittleren und hohen bis sehr hohen SCORE-Risikogruppe für tödliche HKE. Das Hochrisiko-Kollektiv für tödliche HKE war vorwiegend männlich und wies häufiger eine Hypertonie oder ein hohes LDL-Cholesterin auf.
Der Einfluss von Überzeugungen gegenüber antihypertensiver Medikation auf die Blutdruckkontrolle wurde an 293 Teilnehmern, die von Oktober 2014 bis März 2017 an der STAAB Kohortenstudie teilgenommen haben, untersucht. Auf ihre Medikamente gesundheitlich angewiesen zu sein gaben 87% der Teilnehmer an, 78.1% stimmten der Aussage zu, dass ihre Medikamente sie vor einer Verschlechterung ihrer Gesundheit schützen. Es zeigte sich ein inverser Zusammenhang zwischen einem höheren Maß an Bedenken gegenüber der verordneten blutdrucksenkenden Medikation und einer besseren Blutdruckkontrolle bei Frauen. Ein signifikanter Zusammenhang zwischen Bedenken gegenüber einer antihypertensiven Medikation und der Blutdruckkontrolle bei Männern ließ sich hingegen nicht feststellen. Es konnten keine statistisch signifikanten Assoziationen für die Notwendigkeit von Medikation in der vorliegen Untersuchung gezeigt werden.
Die Häufigkeit und Determinanten für die Empfehlung eines ärztlichen Lebensstils wurde bei 665 Teilnehmern der STAAB Kohortenstudie ohne vorbestehende HKE (Primärprävention) und bei 536 Koronarpatienten der EUROASPIRE IV Studie (Sekundärprävention) untersucht.
Mit Ausnahme der Empfehlung zum Rauchverzicht erhielten die Patienten der EUROASPIRE IV Studie häufiger ärztliche Lebensstilempfehlungen verglichen mit Teilnehmern der STAAB Kohortenstudie: (Rauchverzicht: STAAB 44.0%, EUROASPIRE 36.7%; Gewichtsreduktion: STAAB 43.9%, EUROASPIRE 69.2%; körperliche Aktivität steigern: STAAB 52.1%, EUROASPIRE 71.4%; gesundes Ernährungsverhalten: STAAB 43.9%, EUROASPIRE 73.1%). Die Chance für den Erhalt von mindestens 50% aufgrund der individuellen Risikofaktoren adäquaten ärztlichen Lebensstilempfehlungen war bei STAAB Teilnehmern mit offensichtlichen oder beobachtbaren kardiovaskulären Risikofaktoren signifikant erhöht (BMI >25kg/m2, Hypertonie, Hyperlipidämie und Diabetes mellitus).
Hingegen erhielten Patienten mit einer vorbestehenden HKE signifikant häufiger eine ärztliche Lebensstilempfehlung bei einem Diabetes mellitus, wobei die Empfehlungshäufigkeit mit zunehmendem Alter abnahm. Die weitergehende nicht publizierte Analyse des Interaktions
Modells zeigte, dass der Zusammenhang zwischen dem Alter und der Empfehlungshäufigkeit bei Patienten mit bereits bestehender HKE stärker ausgeprägt war, als bei Teilnehmern der STAAB Kohortenstudie ohne koronare HKE. Weiterhin war der Zusammenhang zwischen einer adäquaten Lebensstilempfehlung und Hyperlipidämie bei Teilnehmern ohne koronares Ereignis signifikant stärker ausgeprägt, im Vergleich zu Patienten mit einer bereits bestehender HKE.
Die Ergebnisse zeigten ein erhebliches Potenzial für eine verbesserte Umsetzung leitliniengerechter Behandlung modifizierbarer kardiovaskulärer Risikofaktoren in der Primär- und Sekundärprävention. Vor dem Hintergrund einer hohen Anzahl kardiovaskulärer Risikofaktoren bei jungen Erwachsenen sollte die Bedeutung der Langzeitfolgen im Arzt
Patienten-Gespräch hervorgehoben und bei der Erarbeitung von Präventionsstrategien, insbesondere für junge Altersgruppen, Beachtung finden. Geschlechtsspezifische
Determinanten hinsichtlich der Kontrolle kardiovaskulärer Risikofaktoren sowie Befürchtungen gegenüber der Medikation sollten stärker im Arzt-Patientengespräch berücksichtigt werden.
Zur Stärkung der Compliance des Patienten bei der Umsetzung eines gesunden Lebensstils,
sollte der Arzt hinsichtlich der Bedeutung von Lebensstilintervention, aber auch im Umgang mit schwierigen Situationen, wie die Empfehlung einer Gewichtsreduktion, sensibilisiert und bei der richtigen Handhabung der Leitlinienempfehlung stärker unterstützt werden.
In 2006, 0.18 Mio pediatric nuclear medicine diagnostic exams were performed worldwide. However, for most of the radiopharmaceuticals used data on biokinetics and, as a consequence on dosimetry, are missing or have not been made publicly available. Therefore, most of the dosimetry assessments presented today for diagnostic agents in children and adolescents rely on the biokinetics data of adults. Even for one of the most common nuclear medicine exams for this patient group, renal scintigraphy with 99mTc-MAG3 for assessing renal function measured data on biokinetics is available only from a study performed on four children of different ages. In particular, renal scans are among the most frequent exams performed on infants and toddlers. Due to the young age, this patient group can be classified as a risk group with a higher probability of developing stochastic radiation effects compared to adults. As there are only limited data on biokinetics and dosimetry in this patient group, the aim of this study is to reassess the dosimetry and the associated radiation risk for a larger number of infants undergoing 99mTc-MAG3 renal scans based on a retrospective analysis of existing patient data.
Data were collected retrospectively from 34 patients younger than 20 months with normal (20 patients) and abnormal renal function (14 patients) undergoing 99mTc-MAG3 scans. The patient-specific organ activity was estimated based on a retrospective calibration which was performed based on a set of two 3D-printed infant kidneys (newborns: 8.6 ml; 1-year-old: 23.4 ml) filled with known activities. Both phantoms were scanned at different positions along the anteroposterior axis inside a water phantom, providing depth- and size-dependent attenuation correction factors for planar imaging. Time-activity curves were determined by drawing kidney, bladder, and whole body regions-of-interest for each patient, and subsequently applying the calibration factor for conversion of counts to activity. Patient-specific time-integrated activity coefficients were obtained by integrating the organ-specific time-activity curves. Absorbed and effective dose coefficients for each patient were assessed with OLINDA/EXM for the provided newborn and 1-year-old phantom. Based on absorbed dose values, the radiation risk estimation was performed individually for each of the 34 patients with the National Cancer Institute’s Radiation Risk Assessment Tool.
The patients’ organ-specific mean absorbed dose coefficients for the patients with normal renal function were 0.04±0.03 mGy/MBq for the kidneys and 0.27±0.24 mGy/MBq for the bladder. This resulted in a mean effective dose coefficient of 0.02±0.02 mSv/MBq. Based on the dosimetry results, the evaluation of the excess lifetime risk (ELR) for the development of radiation-induced cancer showed that the group of newborns has an ELR of 16.8 per 100,000 persons, which is higher in comparison with the 1-year-old group with an ELR of 14.7 per 100,000 persons. With regard to the 14 patients with abnormal renal function, the mean values for the organ absorbed dose coefficients for the patients were: 0.40±0.34 mGy/MBq for the kidneys and 0.46±0.37 mGy/MBq for the bladder. The corresponding effective dose coefficients (mSv/MBq) was: 0.05±0.02 mSv/MBq. The mean ELR (per 100,000 persons) for developing cancer from radiation exposure for patients with abnormal renal function was 29.2±18.7 per 100,000 persons.
As a result, the radiation-associated stochastic risk increases with the organ doses, taking age- and gender-specific influences into account. Overall, the lifetime radiation risk associated with the 99mTc-MAG3 scans is very low in comparison to the general population risk for developing cancer.
Furthermore, due to the increasing demand for PET-scans in children and adolescents with 68Ga-labelled peptides, in this work published data sets for those compounds were analyzed to derive recommendations for the administered activities in children and adolescents. The recommendation for the activities to be administered were based on the weight-independent effective dose model, proposed by the EANM Pediatric Dosage Card for application in pediatric nuclear medicine. The aim was to derive recommendations on administered activities for obtaining age-independent effective doses. Consequently, the corresponding weight-dependent effective dose coefficients were rescaled according to the formalism of the EANM dosage card, to determine the radiopharmaceutical class of 68Ga-labeled peptides (“multiples”), and to calculate the baseline activities based on the biokinetics of these compounds and an upper limit of the administered activity of 185 MBq for an adult. Analogous to 18F-fluoride, a minimum activity of 14 MBq is recommended. As a result, for those pediatric nuclear medicine applications involving 68Ga-labeled peptides, new values for the EANM dosage card were proposed and implemented based on the results derived in this work.
Overall, despite the low additional radiation-related cancer risk, all efforts should be undertaken to optimize administered activities in children and adolescents for obtaining sufficient diagnostic information with minimal associated radiation risk.
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.
In mammals, anucleate platelets circulate in the blood flow and are primarily responsible for maintaining functional hemostasis. Platelets are generated in the bone marrow (BM) by megakaryocytes (MKs), which mainly reside directly next to the BM sinusoids to release proplatelets into the blood. MKs originate from hematopoietic stem cells and are thought to migrate from the endosteal to the vascular niche during their maturation, a process, which is, despite being intensively investigated, still not fully understood.
Long-term intravital two photon microscopy (2PM) of MKs and vasculature in murine bone marrow was performed and mean squared displacement analysis of cell migration was performed. The MKs exhibited no migration, but wobbling-like movement on time scales of 3 h. Directed cell migration always results in non-random spatial distribution. Thus, a computational modelling algorithm simulating random MK distribution using real 3D light-sheet fluorescence microscopy data sets was developed. Direct comparison of real and simulated random MK distributions showed, that MKs exhibit a strong bias to vessel-contact. However, this bias is not caused by cell migration, as non-vessel-associated MKs were randomly distributed in the intervascular space. Furthermore, simulation studies revealed that MKs strongly impair migration of other cells in the bone marrow by acting as large-sized obstacles. MKs are thought to migrate from the regions close to the endosteum towards the vasculature during their maturation process. MK distribution as a function of their localization relative to the endosteal regions of the bones was investigated by light sheet fluorescence microscopy (LSFM). The results show no bone-region dependent distribution of MKs. Taken together, the newly established methods and obtained results refute the model of MK migration during their maturation.
Ischemia reperfusion (I/R) injury is a frequent complication of cerebral ischemic stroke, where brain tissue damage occurs despite successful recanalization. Platelets, endothelial cells and immune cells have been demonstrated to affect the progression of I/R injury in experimental mouse models 24 h after recanalization. However, the underlying Pathomechanisms, especially in the first hours after recanalization, are poorly understood.
Here, LSFM, 2PM and complemental advanced image analysis workflows were established for investigation of platelets, the vasculature and neutrophils in ischemic brains. Quantitative analysis of thrombus formation in the ipsilateral and contralateral hemispheres at different time points revealed that platelet aggregate formation is minimal during the first 8 h after recanalization and occurs in both hemispheres. Considering that maximal tissue damage already is present at this time point, it can be concluded that infarct progression and neurological damage do not result from platelet aggregated formation. Furthermore, LSFM allowed to confirm neutrophil infiltration into the infarcted hemisphere and, here, the levels of endothelial cell marker PECAM1 were strongly reduced. However, further investigations must be carried out to clearly identify the role of neutrophils and the endothelial cells in I/R injury.
Introduction: During inflammation, reactive oxygen species (ROS) such as Hydrogen peroxide accumulate at the inflammation site and by oxidizing lipids, they produce metabolites such as 4-hydroxynonenal (4-HNE) and oxidized phospholipids (OxPLs). Transient receptor potential ankyrin 1 (TRPA1) and vanilloid 1 (TRPV1) are ligand gated ion channels that are expressed on nociceptors and their activation elicits pain. Hydrogen peroxide and 4-HNE are endogenous ligands for TRPA1 and their role in inflammatory pain conditions has been shown. OxPLs play a major pro-inflammatory role in many pathologies including atherosclerosis and multiple sclerosis. E06/T15 is a mouse IgM mAb that specifically binds oxidized phosphatidylcholine. D-4F is an apolipoprotein A-I mimetic peptide with a very high affinity for OxPLs and possess anti-inflammatory properties. E06 mAb and D-4F peptide protect against OxPLs-induced damage in atherosclerosis in vivo.
Methods: To investigate the role of ROS and their metabolites in inflammatory pain, I utilized a combination of diverse and complex behavioral pain measurements and binding assays. I examined E06 mAb and D-4F as local treatment options for hypersensitivity evoked by endogenous and exogenous activators of TRPA1 and TRPV1 as well as in inflammatory and OxPL-induced pain models in vivo. 4-HNE, hydrogen peroxide as ROS source and mustard oil (AITC) were used to activate TRPA1, while capsaicin was used to activate TRPV1.
Results: Intraplantar injection of oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine (OxPAPC) into rats’ hind paw elicited thermal and mechanical hypersensitivity. Genetic and pharmacological evidence in vivo confirmed the role of TRPA1 in OxPLs-induced hypersensitivity. OxPLs formation increased in complete Freund’s adjuvant (CFA)-induced inflamed rats’ paw. E06 mAb and D-4F prevented OxPAPC–induced mechanical and thermal hypersensitivity (hyperalgesia) as well as CFA-induced mechanical hypersensitivity. Also, all irritants induced thermal and mechanical hypersensitivity as well as affective-emotional responses and spontaneous nocifensive behaviors. E06 mAb blocked prolonged mechanical hypersensitivity by all but hydrogen peroxide. In parallel, D-4F prevented mechanical hypersensitivity induced by all irritants as well as thermal hypersensitivity induced by capsaicin and 4-HNE. In addition, competitive binding assays showed that all TRPA1/V1 agonists induced prolonged formation of OxPLs in the paw tissue explaining the anti-nociceptive properties of E06 mAb and D-4F. Finally, the potential of gait analysis as a readout for non-provoked pain behavioral measurements were examined.
Conclusion and implications: OxPLs were characterized as novel targets in inflammatory pain. Treatment with the monoclonal antibody E06 or apolipoprotein A-I mimetic peptide D-4F are suggested as potential inflammatory pain medications. OxPLs’ role in neuropathic pain is yet to be investigated.
Breast cancer is the most common cancer among women worldwide and the second most common cause of cancer death in the developed countries. As the current state of the art in first-line drug screenings is highly ineffective, there is an urgent need for novel test systems that allow for reliable predictions of drug sensitivity.
In this study, a tissue engineering approach was used to successfully establish and standardize a 3-dimensional (3D) mamma carcinoma test system that was optimized for the testing of anti-tumour therapies as well as for the investigation of tumour biological issues. This 3D test system is based on the decellularised scaffold of a porcine small intestinal segment and represents the three molecular subsets of oestrogen receptor-positive, HER2/Neu-overexpressing and triple negative breast cancer (TNBC). The characterization of the test system with respect to morphology as well as the expression of markers for epithelial-mesenchymal transition (EMT) and differentiation indicate that the 3D tumour models cultured under static and dynamic conditions reflect tumour relevant features and have a good correlation with in vivo tumour tissue from the corresponding xenograft models. In this respect, the dynamic culture in a flow bioreactor resulted in the generation of tumour models that exhibited best reflection of the morphology of the xenograft material. Furthermore, the proliferation indices of 3D models were significantly reduced compared to 2-dimensional (2D) cell culture and therefore better reflect the in vivo situation. As this more physiological proliferation index prevents an overestimation of the therapeutic effect of cytostatic compounds, this is a crucial advantage of the test system compared to 2D culture. Moreover, it could be shown that the 3D models can recapitulate different tumour stages with respect to tumour cell invasion. The scaffold SISmuc with the preserved basement membrane structure allowed the investigation of invasion over this barrier which tumour cells of epithelial origin have to cross in in vivo conditions during the process of metastasis formation. Additionally, the data obtained from ultrastructural analysis and in situ zymography indicate that the invasion observed is connected to a tumour cell-associated change in the basement membrane in which matrix metalloproteinases (MMPs) are also involved. This features of the model in combination with the mentioned methods of analysis could be used in the future to mechanistically investigate invasive processes and to test anti-metastatic therapy strategies.
The validation of the 3D models as a test system with respect to the predictability of therapeutic effects was achieved by the clinically relevant targeted therapy with the monoclonal antibody trastuzumab which induces therapeutic response only in patients with HER2/Neu-overexpressing mamma carcinomas due to its specificity for HER2. While neither in 2D nor in 3D models of all molecular subsets a clear reduction of cell viability or an increase in apoptosis could be observed, a distinct increase in antibody-dependent cell-mediated cytotoxicity (ADCC) was detected only in the HER2/NEU-overexpressing 3D model with the help of an ADCC reporter gene assay that had been adapted for the application in the 3D model in the here presented work. This correlates with the clinical observations and underlines the relevance of ADCC as a mechanism of action (MOA) of trastuzumab. In order to measure the effects of ADCC on the tumour cells in a direct way without the indirect measurement via a reporter gene, the introduction of an immunological component into the models was required. This was achieved by the integration of peripheral blood mononuclear cells (PBMCs), thereby allowing the measurement of the induction of tumour cell apoptosis in the HER2/Neu-overexpressing model. Hence, in this study an immunocompetent model could be established that holds the potential for further testing of therapies from the emergent field of cancer immunotherapies.
Subsequently, the established test system was used for the investigation of scientific issues from different areas of application. By the comparison of the sensitivity of the 2D and 3D model of TNBC towards the water-insoluble compound curcumin that was applied in a novel nanoformulation or in a DMSO-based formulation, the 3D test system was successfully applied for the evaluation of an innovative formulation strategy for poorly soluble drugs in order to achieve cancer therapy-relevant concentrations. Moreover, due to the lack of targeted therapies for TNBC, the TNBC model was applied for testing novel treatment strategies. On the one hand, therapy with the WEE1 kinase inhibitor MK 1775 was evaluated as a single agent as well as in combination with the chemotherapeutic agent doxorubicin. This therapy approach did not reveal any distinct benefits in the 3D test system in contrast to testing in 2D culture. On the other hand, a novel therapy approach from the field of cellular immunotherapies was successfully applied in the TNBC 3D model. The treatment with T cells that express a chimeric antigen receptor (CAR) against ROR1 revealed in the static as well as in the dynamic model a migration of T cells into the tumour tissue, an enhanced proliferation of T cells as well as an efficient lysis of the tumour cells via apoptosis and therefore a specific anti-cancer effect of CAR-transduced T cells compared to control T cells. These results illustrate that the therapeutic application of CAR T cells is a promising strategy for the treatment of solid tumours like TNBC and that the here presented 3D models are suitable for the evaluation and optimization of cellular immunotherapies.
In the last part of this work, the 3D models were expanded by components of the tumour stroma for future applications. By coculture with fibroblasts, the natural structures of the intestinal scaffold comprising crypts and villi were remodelled and the tumour cells formed tumour-like structures together with the fibroblasts. This tissue model displayed a strong correlation with xenograft models with respect to morphology, marker expression as well as the activation of dermal fibroblasts towards a cancer-associated fibroblast (CAF) phenotype. For the integration of adipocytes which are an essential component of the breast stroma, a coculture with human adipose-derived stromal/stem cells (hASCs) which could be successfully differentiated along the adipose lineage in 3D static as well as dynamic models was established. These models are suitable especially for the mechanistic analysis of the reciprocal interaction between tumour cells and adipocytes due to the complex differentiation process.
Taken together, in this study a human 3D mamma carcinoma test system for application in the preclinical development and testing of anti-tumour therapies as well as in basic research in the field of tumour biology was successfully established. With the help of this modular test system, relevant data can be obtained concerning the efficacy of therapies in tumours of different molecular subsets and different tumour stages as well as for the optimization of novel therapy strategies like immunotherapies. In the future this can contribute to improve the preclinical screening and thereby to reduce the high attrition rates in pharmaceutical industry as well as the amount of animal experiments.
Tumor necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK) is a member of the TNF superfamily (TNFSF) and is as such initially expressed as type II class transmembrane glycoprotein from which a soluble ligand form can be released by proteolytic processing. While the expression of TWEAK has been detected at the mRNA level in various cell lines and cell types, its cell surface expression has so far only been documented for dendritic cells, monocytes and interferon-γ stimulated NK cells. The fibroblast growth factor-inducible-14 (Fn14) is a TRAF2-interacting receptor of the TNF receptor superfamily (TNFRSF) and is the only receptor for TWEAK. The expression of Fn14 is strongly induced in a variety of non-hematopoietic cell types after tissue injury. The TWEAK/Fn14 system induces pleiotropic cellular activities such as induction of proinflammatory genes, stimulation of cellular angiogenesis, proliferation, differentiation, migration and in rare cases induction of apoptosis. On the other side, Toll-like receptor3 (TLR3) is one of DNA- and RNA-sensing pattern recognition receptors (PRRs), plays a crucial role in the first line of defense against virus and invading foreign pathogens and cancer cells. Polyinosinic-polycytidylic acid poly(I:C) is a synthetic analog of dsRNA, binds to TLR3 which acts through the adapter TRIF/TICAM1, leading to cytokine secretion, NF-B activation, IRF3 nuclear translocation, inflammatory response and may also elicit the cell death. TWEAK sensitizes cells for TNFR1-induced apoptosis and necroptosis by limiting the availability of protective TRAF2-cIAP1 and TRAF2-cIAP2 complexes, which interact with the TNFR1-binding proteins TRADD and RIPK1. In accordance with the fact that poly(I:C)-induced signaling also involves these proteins, we found enhanced necroptosis-induction in HaCaT and HeLa-RIPK3 by poly(I:C) in the presence of TWEAK (Figure 24). Analysis of a panel of TRADD, FADD, RIPK1 and caspase-8 knockout cells revealed furthermore similarities and differences in the way how these molecules act in cell death signaling by poly(I:C)/TWEAK and TNF and TRAIL. RIPK1 turned out to be essential for poly(I:C)/TWEAK-induced caspase-8-mediated apoptosis but was dispensable for these responses in TNF and TRAIL signaling. Lack of FADD protein abrogated TRAIL- but not TNF- and poly(I:C)-induced necroptosis. Moreover, we observed that both long and short FLIP rescued HaCaT and HeLa-RIPK3 cells from poly(I:C)-induced apoptosis or necroptosis.
To sum up, our results demonstrate that TWEAK, which is produced by interferon stimulated myeloid cells, controls the induction of apoptosis and necroptosis by the TLR3 ligand poly(I:C) and may thus contribute to cancer or anti-viral immunity treatment.
The etiology of anxiety disorders is multifactorial with contributions from both
genetic and environmental factors. Several susceptibility genes of anxiety disorders or
anxiety-related intermediate phenotypes have been identified, including the
serotonin transporter gene (5-HTT) and the neuropeptide S receptor gene (NPSR1),
which have been shown to modulate responses to distal and acute stress experiences.
For instance, gene-environment interaction (GxE) studies have provided evidence
that both 5-HTT and NPSR1 interact with environmental stress, particularly
traumatic experiences during childhood, in the moderation of anxiety traits, and
both 5-HTT and NPSR1 have been implicated in hypothalamic-pituitary-adrenal
(HPA) axis reactivity – an intermediate phenotype of mental disorders – in response
to acute stress exposure. The first part of this thesis aimed to address the interplay of
variations in both 5-HTT and NPSR1 genes and distal stress experiences, i.e.
childhood trauma, in the moderation of anxiety-related traits, extended by
investigation of the potentially protective effect of positive influences, i.e. elements of
successful coping such as general self-efficacy (GSE), on a GxE risk constellation by
introducing GSE as an indicator of coping ability (“C”) as an additional dimension in
a GxExC approach conferring – or buffering – vulnerability to anxiety. Increased
anxiety was observed in 5-HTTLPR/rs25531 LALA genotype and NSPR1 rs324981 AA
genotype carriers, respectively, with a history of childhood maltreatment but only in
the absence of a person’s ability to cope with adversity, whereas a dose-dependent
effect on anxiety traits as a function of maltreatment experiences irrespective of
coping characteristics was observed in the presence of at least one 5-HTT S/LG or
NSPR1 T allele, respectively. The second part of this thesis addressed the respective
impact of 5-HTT and NPSR1 variants on the neuroendocrine, i.e. salivary cortisol
response to acute psychosocial stress by applying the Maastricht Acute Stress Test
(MAST). A direct effect of NPSR1 – but not 5-HTT – on the modulation of acute
stress reactivity could be discerned, with carriers of the more active NPSR1 T allele
Summary
III
displaying significantly higher overall salivary cortisol levels in response to the MAST
compared to AA genotype carriers.
In summary, study 1 observed a moderating effect of GSE in interaction with
childhood maltreatment and 5-HTT and NPSR1, respectively, in an extended GxExC
model of anxiety risk, which may serve to inform targeted preventive interventions
mitigating GxE risk constellations and to improve therapeutic interventions by
strengthening coping ability as a protective mechanism to promote resilient
functioning. In study 2, a modulation of HPA axis function, considered to be an
endophenotype of stress-related mental disorders, by NPSR1 gene variation could be
discerned, suggesting neuroendocrine stress reactivity as an important potential
intermediate phenotype of anxiety given findings linking NPSR1 to dimensional and
categorical anxiety. Results from both studies may converge within the framework of
a multi-level model of anxiety risk, integrating neurobiological, neuroendocrine,
environmental, and psychological factors that act together in a highly complex
manner towards increasing or decreasing anxiety risk.
G protein-coupled receptor research looks out for new technologies to elucidate the complex
processes of receptor activation, function and downstream signaling with spatiotemporal
resolution, preferably in living cells and organisms. A thriving approach consists in making use
of the unsurpassed properties of light, including its high precision in space and time, noninvasiveness
and high degree of orthogonality regarding biological processes. This is realized
by the incorporation of molecular photoswitches, which are able to effectively respond to light,
such as azobenzene, into the structure of a ligand of a given receptor. The muscarinic
acetylcholine receptors belong to class A GPCRs and have received special attention in this
regard due to their role as a prototypic pharmacological system and their therapeutic potential.
They mediate the excitatory and inhibitory effects of the neurotransmitter acetylcholine and
thus regulate diverse important biological processes, especially many neurological functions in
our brain.
In this work, the application of photopharmacological tool compounds to muscarinic receptors
is presented, consisting of pharmacophores extended with azobenzene as light-responsive
motif. Making use of the dualsteric concept, such photochromic ligands can be designed to bind
concomitantly to the orthosteric and allosteric binding site of the receptor, which is
demonstrated for BQCAAI (M1) and PAI (M2) and may lead to subtype- and functionalselective
photoswitchable ligands, suitable for further ex vivo and in vivo studies.
Moreover, photoswitchable ligands based on the synthetic agonist iperoxo were investigated
extensively with regard to their photochemical behavior and pharmacological profile, outlining
the advantages and challenges of using red-shifted molecular photoswitches, such as tetraortho-
fluoro azobenzene. For the first time on a GPCR it was examined, which impact the
different substitution pattern has on both the binding and the activity on the M1 receptor. Results
show that substituted azobenzenes in photopharmacological compounds (F4-photoiperoxo and
F4-iper-azo-iper) not just represent analogs with other photophysical properties but can exhibit
a considerably different biological profile that has to be investigated carefully.
The achievements gained in this study can give important new insights into the binding mode
and time course of activation processes, enabling precise spatial and temporal resolution of the
complex signaling pathway of muscarinic receptors. Due to their role as exemplary model
system, these findings may be useful for the investigation into other therapeutically relevant
GPCRs.