TY - JOUR A1 - Hinderer, Svenja A1 - Shen, Nian A1 - Ringuette, Léa-Jeanne A1 - Hansmann, Jan A1 - Reinhardt, Dieter P A1 - Brucker, Sara Y A1 - Davis, Elaine C A1 - Schenke-Layland, Katja T1 - In vitro elastogenesis: instructing human vascular smooth muscle cells to generate an elastic fiber-containing extracellular matrix scaffold JF - Biomedical Materials N2 - Elastic fibers are essential for the proper function of organs including cardiovascular tissues such as heart valves and blood vessels. Although (tropo)elastin production in a tissue-engineered construct has previously been described, the assembly to functional elastic fibers in vitro using human cells has been highly challenging. In the present study, we seeded primary isolated human vascular smooth muscle cells (VSMCs) onto 3D electrospun scaffolds and exposed them to defined laminar shear stress using a customized bioreactor system. Increased elastin expression followed by elastin deposition onto the electrospun scaffolds, as well as on newly formed fibers, was observed after six days. Most interestingly, we identified the successful deposition of elastogenesis-associated proteins, including fibrillin-1 and -2, fibulin-4 and -5, fibronectin, elastin microfibril interface located protein 1 (EMILIN-1) and lysyl oxidase (LOX) within our engineered constructs. Ultrastructural analyses revealed a developing extracellular matrix (ECM) similar to native human fetal tissue, which is composed of collagens, microfibrils and elastin. To conclude, the combination of a novel dynamic flow bioreactor and an electrospun hybrid polymer scaffold allowed the production and assembly of an elastic fiber-containing ECM. KW - elastin KW - elastic fibers KW - electrospinning KW - tissue engineering KW - regenerative medicine KW - heart valve KW - cardiovascular Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-254074 VL - 10 IS - 3 ER - TY - JOUR A1 - Wittmann, Katharina A1 - Sieber, Cornel A1 - von Stengel, Simon A1 - Kohl, Matthias A1 - Freiberger, Ellen A1 - Jakob, Franz A1 - Lell, Michael A1 - Engelke, Klaus A1 - Kemmler, Wolfgang T1 - Impact of whole body electromyostimulation on cardiometabolic risk factors in older women with sarcopenic obesity: the randomized controlled FORMOsA-sarcopenic obesity study JF - Clinical Interventions in Aging N2 - Background: Sarcopenic obesity (SO) is characterized by a combination of low muscle and high fat mass with an additive negative effect of both conditions on cardiometabolic risk. The aim of the study was to determine the effect of whole-body electromyostimulation (WB-EMS) on the metabolic syndrome (MetS) in community-dwelling women aged ≥70 years with SO. Methods: The study was conducted in an ambulatory university setting. Seventy-five community-dwelling women aged ≥70 years with SO living in Northern Bavaria, Germany, were randomly allocated to either 6 months of WB-EMS application with (WB-EMS&P) or without (WB-EMS) dietary supplementation (150 kcal/day, 56% protein) or a non-training control group (CG). WB-EMS included one session of 20 min (85 Hz, 350 µs, 4 s of strain–4 s of rest) per week with moderate-to-high intensity. The primary study endpoint was the MetS Z-score with the components waist circumference (WC), mean arterial pressure (MAP), triglycerides, fasting plasma glucose, and high-density lipoprotein cholesterol (HDL-C); secondary study endpoints were changes in these determining variables. Results: MetS Z-score decreased in both groups; however, changes compared with the CG were significant (P=0.001) in the WB-EMS&P group only. On analyzing the components of the MetS, significant positive effects for both WB-EMS groups (P≤0.038) were identified for MAP, while the WB-EMS group significantly differed for WC (P=0.036), and the WB-EMS&P group significantly differed for HDL-C (P=0.006) from the CG. No significant differences were observed between the WB-EMS groups. Conclusion: The study clearly confirms the favorable effect of WB-EMS application on the MetS in community-dwelling women aged ≥70 years with SO. However, protein-enriched supplements did not increase effects of WB-EMS alone. In summary, we considered this novel technology an effective and safe method to prevent cardiometabolic risk factors and diseases in older women unable or unwilling to exercise conventionally. KW - sarcopenia KW - obesity KW - whole-body electromyostimulation KW - cardiovascular KW - metabolic risk KW - metabolic syndrome KW - community-dwelling KW - older people Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-164930 VL - 11 ER - TY - THES A1 - Panjwani, Priyadarshini T1 - Induction, Imaging, Histo-morphological and Molecular Characterization of Myocarditis in the Rat to Explore Novel Diagnostic Strategies for the Detection of Myocardial Inflammation T1 - Induktion, Bildgebung und, Histo-morphologische sowie Molekulare Charakterisierung der Myokarditis im Rattenmodell zur Entwicklung neuer diagnostischer Strategien zum Nachweis von Herzmuskelentzündungen N2 - Fulminant myocarditis is rare but a potentially life-threatening disease. Acute or mild myocarditis following acute ischemia is generally associated with a profound activation of the host’s immune system. On one hand this is mandatory to protect the host’s heart by fighting the invading agents (i.e., bacteria, viruses or other microbial agents) and/or to induce healing and repair processes in the damaged myocardium. On other hand, uncontrolled activation of the immune system may result in the generation of auto-reactive (not always beneficial) immune cells. Myocarditis or inflammatory cardiomyopathy is characterized by focal or diffuse infiltrates, myocyte necrosis and/or apoptosis and subsequent fibrotic replacement of the heart muscle. In humans, about 30% of the myocarditis-patients develop dilated cardiomyopathy. As the clinical picture of myocarditis is multifaceted, it is difficult to diagnose the disease. Therefore, the main goal of the present work was to test and further develop novel non-invasive methods for the detection of myocardial inflammation by employing both contrast enhanced MRI techniques as well as novel nuclear tracers that are suitable for in vivo PET/ SPECT imaging. As a part of this thesis, a pre-clinical animal model was successfully established by immunizing female Lewis rats with whole-porcine cardiac myosin (CM). Induction of Experimental Autoimmune Myocarditis (EAM) is considered successful when anti-myosin antibody titers are increased more than 100-fold over control animals and pericardial effusion develops. In addition, cardiac tissues from EAM-rats versus controls were analyzed for the expression of various pro-inflammatory and fibrosis markers. To further exploit non-invasive MRI techniques for the detection of myocarditis, our EAM-rats were injected either with (1) ultra-small Paramagnetic iron oxide particles (USPIO’s; Feraheme®), allowing for in vivo imaging , (2) micron sized paramagnetic iron oxide particles (MPIO) for ex vivo inflammatory cell-tracking by cMRI, or (3) with different radioactive nuclear tracers (67gallium citrate, 68gallium-labeled somatostatin analogue, and 68gallium-labeled cyclic RGD-peptide) which in the present work have been employed for autoradiographic imaging, but in principle are also suitable for in vivo nuclear imaging (PET/SPECT). In order to compare imaging results with histology, consecutive heart sections were stained with hematoxylin & eosin (HE, for cell infiltrates) and Masson Goldner trichrome (MGT, for fibrosis); in addition, immuno-stainings were performed with anti-CD68 (macrophages), anti-SSRT2A (somatostatin receptor type 2A), anti-CD61 (β3-integrins) and anti-CD31 (platelet endothelial cell adhesion molecule 1). Sera from immunized rats strongly reacted with cardiac myosin. In immunized rats, echocardiography and subsequent MRI revealed huge amounts of pericardial effusion (days 18-21). Analysis of the kinetics of myocardial infiltrates revealed maximal macrophage invasion between days 14 and 28. Disappearance of macrophages resulted in replacement-fibrosis in formerly cell-infiltrated myocardial areas. This finding was confirmed by the time-dependent differential expression of corresponding cytokines in the myocardium. Immunized animals reacted either with an early or a late pattern of post-inflammation fibrosis. Areas with massive cellular infiltrates were easily detectible in autoradiograms showing a high focal uptake of 67gallium-citrate and 68gallium labeled somatostatin analogues (68Ga DOTA-TATE). Myocardium with a loss of cardiomyocytes presented a high uptake of 68gallium labeled cyclic RGD-peptide (68Ga NOTA-RGD). MRI cell tracking experiments with Feraheme® as the contrast-agent were inconclusive; however, strikingly better results were obtained when MPIOs were used as a contrast-agent: histological findings correlated well with in vivo and ex vivo MPIO-enhanced MRI images. Imaging of myocardial inflammatory processes including the kinetics of macrophage invasion after microbial or ischemic damage is still a major challenge in, both animal models and in human patients. By applying a broad panel of biochemical, histological, molecular and imaging methods, we show here that different patterns of reactivity may occur upon induction of myocarditis using one and the same rat strain. In particular, immunized Lewis rats may react either with an early or a late pattern of macrophage invasion and subsequent post-inflammation fibrosis. Imaging results achieved in the acute inflammatory phase of the myocarditis with MPIOs, 67gallium citrate and 68gallium linked to somatostatin will stimulate further development of contrast agents and radioactive-nuclear tracers for the non-invasive detection of acute myocarditis and in the near future perhaps even in human patients. N2 - Eine fulminant verlaufende Myokarditis ist eine seltene aber potentiell lebensbedrohliche Erkrankung. Akute oder chronische Myokarditis gehen generell mit einer starken Aktivierung des Immunsystems der Betroffenen einher. Zum einen ist dies notwendig, um das Herz durch Bekämpfung der Eindringlinge (z.B. Bakterien, Viren oder andere mikrobielle Erreger) zu schützen und/oder Heilungs- und Reparaturprozesse im geschädigten Myokard einzuleiten. Zum anderen kann eine unkontrollierte Aktivierung des Immunsystems aber auch zur Entstehung von (nicht immer vorteilhaften) auto-reaktiven Immunzellen führen. Eine Myokarditis oder entzündliche Kardiomyopathie ist charakterisiert durch fokale oder diffuse Infiltrate, Nekrose und/oder Apoptose der Myozyten und einen fortschreitenden fibrotischen Ersatz des Herzmuskelgewebes. Beim Menschen entwickeln etwa 30% der Myokarditis-Patienten eine dilatative Kardiomyopathie. Da das klinische Bild der Myokarditis sehr vielfältig sein kann, ist die Diagnosestellung dieser Erkrankung schwierig. Deshalb war es das Kernziel dieser Arbeit, nicht-invasive Methoden zum Nachweis myokardialer Entzündungen zu testen, und dabei neue Bildgebungsverfahren unter Einsatz von neuen MRT-Kontrastmitteln sowie neuen nuklearen Tracern, die auch für PET/SPECT geeignet wären, zu entwickeln. Diese Verfahren wurden von uns zunächst an einem human-analogen Ratten-Modell evaluiert, mit dem Ziel später evtl. auch einmal beim Menschen eingesetzt werden zu können. Für unser präklinisches Tiermodell wurden weibliche Lewis-Ratten mit kardialem Myosin aus Schweinen immunisiert. Die erfolgreiche Induktion einer „Experimentellen Autoimmunen Myokarditis (EAM)“ wurde durch einen signifikanten Anstieg der Anti-Myosin Antikörpertiter in immunisierten Tieren und die Ausbildung eines Perikardergusses (Echokardiographie) bestätigt. Zusätzlich wurde aus apikalem kardialem Gewebe RNA isoliert und die Expression verschiedener pro-inflammatorischer und pro-fibrotischer molekularer Marker untersucht. Um die Bildgebung mittels kontrast-verstärktem cMRT zu optimieren, wurden den Tieren entweder kleine Eisenoxid-Nanopartikel (Ultra small paramagnetic iron oxide particles, USPIO; Feraheme®), oder sog. ,,Micronsized paramagnetic iron oxide particles (MPIO)‘‘ für das Tracking inflammatorischer Zellen injiziert. Im daraufolgenden Schritt wurden radioaktive nukleare Tracer (67Gallium-Citrat, 68Gallium-markierte Somatostatin-Analoga und 68Gallium-markierte zyklische RGD-Peptide) injiziert, um dann Autoradiogramme von Herzschnitten zu gewinnen. KW - Ratte KW - inflammation KW - Myokarditis KW - Kernspintomografie KW - myocarditis KW - MRI KW - cardiovascular KW - Entzündung Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-122469 ER - TY - THES A1 - Hofmann, Michael T1 - Troponin-I-Freisetzung bei kardiochirurgischen Bypassoperationen mit und ohne Herz-Lungen-Maschine T1 - Troponin-I-Release at cardiovascular bypassoperations with and without heart-lung-machine N2 - In dieser Studie wurden der Troponin-I-Verlauf, sowie die Serumwerte von Myoglobin, CK und CK-MB prä- und postoperativ nach einem Bypasseingriff am Herzen untersucht. Die Patienten wurden entweder mit Hilfe der Herz-Lungen-Maschine oder im sogenannten Off-Pump-Verfahren operiert. Bei den Patienten der Off-Pump-Gruppe wurde ebenfalls eine Koronarbypassoperation durchgeführt, jedoch am schlagenden Herzen ohne den Einsatz einer Herz-Lungen-Maschine. Die Ergebnisse dieser Studie zeigten, dass es deutliche Unterschiede in den postoperativen Troponin-I-Verläufen zwischen Koronarbypassoperationen mit Herz-Lungen-Maschine und Bypassoperationen am schlagenden Herzen ohne Herz-Lungen-Maschine (Off-Pump-Methode) gibt. Der Troponin-I-Verlauf zeigte in der HLM-Gruppe einen deutlich höheren Troponin-I-Anstieg im gesamten untersuchten postoperativen Verlauf im Vergleich zu den Konzentrationsverläufen des Troponin-I in der Off-Pump-Gruppe. Die weiteren untersuchten Parameter CK, CK-MB und Myoglobin zeigten diese deutlichen Unterschiede in den Konzentrationsverläufen zwischen den beiden Gruppen, wahrscheinlich aufgrund des Gewebeschadens durch die Operation z.B. durch Muskelverletzung, Mediastinaleröffnung, Perikarderöffnung, nicht. In Bezug auf den prozentualen CK-MB-Anteil der beiden Gruppen lag sogar ein annähernd deckungsgleicher Verlauf vor. N2 - Troponin-I-Release at cardiovascular bypassoperations with and without heart-lung-machine KW - Troponin I KW - kardiochirurgisch KW - Bypassoperation KW - Herz-Lungen-Maschine KW - Off-Pump KW - troponin-I KW - bypassoperation KW - heart-lung-machine KW - off-pump KW - cardiovascular Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-16843 ER - TY - THES A1 - Rabie, Tamer T1 - Cellular regulation of platelet glycoprotein VI : in vivo and in vitro studies in mice T1 - Zelluläre Regulation von Plättchen Glykoprotein VI : in vivo und in vitro Studien in der Maus N2 - Platelet interaction with the subendothelium is essential to limit blood loss after tissue injury. However, upon rupture of atherosclerotic plaques, this interaction may result in blood vessel occlusion leading to life threatening diseases such as myocardial infarction or stroke. Among the subendothelial matrix proteins, collagen is considered to be the most thrombogenic component as it directly activates platelets. Platelets interact with collagen, either indirectly through glycoprotein (GP) Ib-V-IX receptor complex, or directly through the major collagen receptor on the platelet surface, GPVI. The work presented here focused on studying the cellular regulation of GPVI. In addition, a possible role for GPVI in thrombus formation induced by atherosclerotic plaque material was investigated and it was found that GPVI plays an important role in this process. Using a recently published mitochondrial injury model, it was found that GPVI contains a cleavage site for a platelet-expressed metalloproteinase. Further studies showed that platelet activation by CRP, or thrombin induced down-regulation of GPIb, but not GPVI. In parallel, cellular regulation of GPV was studied and it was found that GPV is cleaved in vitro by the metalloproteinase ADAM17. In previous studies it was shown that injection of mice with the anti-GPVI mAb, JAQ1, induces GPVI down-regulation, which is associated with a strong, but transient, thrombocytopenia. Using new anti-GPVI mAbs, which bind different epitopes on the receptor, it is shown in this study that GPVI down-regulation occurs in an epitope-independent manner. Further experiments showed that antibody treatment induces a transient, but significant increase in bleeding time. Using different genetically modified mice, it is shown that, upon antibody injection, GPVI is both, shed from the platelet surface and internalized into the platelet. Signaling through the immunoreceptor tyrosine-based activation motif (ITAM) of the FcR chain is essential for both processes, while LAT and PLC2 are essential for the shedding process only. Antibody-induced increase in bleeding time and thrombocytopenia were absent in LAT deficient mice, showing that it is possible to uncouple the associated side effects from the down-regulation process. As antibody-induced GPVI internalization still occurs in LAT and PLC2 deficient mice, this suggests a novel signaling pathway downstream of GPVI that has not been described so far. N2 - Plättchen Interaktion mit dem Subendothel ist für die Blutstillung essentiell. Dies kann jedoch nach dem Aufbrechen atherosklerotischer Plaques zu lebensbedrohlicher Erkrankungen wie Infarkt oder Schlaganfall führen. Kollagen, welches die Plättchen dirket aktiviert, ist der thrombogenste Bestandteil der Extrazellularmatrix (EZM). Die Bindung zwischen Plättchen und Kollagen wird sowohl indirekt durch den Glykoprotein (GP) Ib-V-IX Rezeptorkomplex, als auch direkt durch den Kollagenrezeptor GPVI, auf der Plättchenoberfläche vermittelt. In der vorliegenden Arbeit wurde die zelluläre Regulation von GPVI untersucht. Des Weiteren wurde die Rolle von GPVI in durch atheroklerotisches Plaquematerial induzierter Thrombusbildung studiert. Hierbei wurde festgestellt, dass GPVI eine wichtige Funktion in diesem Prozess spielt. Mittels eines jüngst publizierten mitochondrialen Verletzungsmodels, konnte gezeigt werden, dass GPVI eine Erkennungsstelle für eine in den Plättchen exprimierte Metalloproteinase besitzt. Mehrere Versuche haben gezeigt, dass Plättchenaktivierung durch CRP, und Thrombin zur Runterregulierung von GPIb aber nicht von GPVI führt. Parallellaufende Untersuchungen zeigten, dass GPV durch die Metalloproteinase ADAM17 in vitro abgespalten wird. Vorherige Studien ergaben, dass die in vivo Behandlung von Mäusen mit dem anti-GPVI Antikörper, JAQ1, zur Runterregulierung des Rezeptors führt. Dieses ist mit einer starken, transienten Thrombozytopenie assoziiert. Mittels neu generierte anti-GPVI Antikörper (JAQ2, 3), die unterschiedliche Bindungsstellen auf GPVI erkennen, konnte demonstriert werden, dass die Antikörper vermittele GPVI Runterregulierung Epitop unabhängig ist. Weitere Untersuchungen ergaben, dass Anitkörperinjektion eine transiente Erhöhung der Blutungszeit verursacht. Mittels genetisch modifizierter Mäuse konnte dargestellt werden, dass die Antikörpergabe GPVI sowohl von der Plättchenoberfläche abgespalten, als auch internalisiert wird. Während die Signaltransduktion durch das ITAM Motif der FcR Kette essentiell für beide Prozesse ist, sind LAT und PLC2 nur für das Abspalten wichtig. Antikörper induzierte Erhöhung der Blutungszeit und Thrombozytopenie sind abwesend in LAT-defizienten Mäuse, was zeigt, dass möglicherweise die GPVI Runterregulierung von den assoziierten Nebenwirkungen zu trennen ist. Da die GPVI Runterregulierung in LAT und –PLC2 defizienten Mäusen weiterhin stattfindet, zeigt dies einen neuen GPVI Signalweg, der bisher noch nicht beschrieben wurde. KW - Maus KW - Thrombozyt KW - Glykoproteine KW - Regulation KW - Biologie KW - Plättchen KW - Maus KW - Thrombose KW - Kardiovaskulär KW - maus KW - platelets KW - thrombosis KW - cardiovascular Y1 - 2005 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-14267 ER -