Karsten Schulze

Differential Expression of Matrix Metalloproteases in Human Fibroblasts with Different Origins

Fibroblasts are widely distributed cells and are responsible for the deposition of extracellular matrix (ECM) components but also secrete ECM-degrading matrix metalloproteases. A finely balanced equilibrium between deposition and degradation of ECM is essential for structural integrity of tissues. In the past, fibroblasts have typically been understood as a uniform cell population with comparable functions regardless of their origin. Here, we determined growth curves of fibroblasts derived from heart, skin, and lung and clearly show the lowest proliferation rate for cardiac fibroblasts. Furthermore, we examined basal expression levels of collagen and different MMPs in these three types of fibroblasts and compared these concerning their site of origin. Interestingly, we found major differences in basal mRNA expression especially for MMP1 and MMP3. Moreover, we treated fibroblasts with TNF-α and observed different alterations under these proinflammatory conditions. In conclusion, fibroblasts show different properties in proliferation and MMP expression regarding their originated tissue.

Increased Left Ventricular Stiffness Impairs Exercise Capacity in Patients with Heart Failure Symptoms Despite Normal Left Ventricular Ejection Fraction

Aims. Several mechanisms can be involved in the development of exercise intolerance in patients with heart failure despite normal left ventricular ejection fraction (HFNEF) and may include impairment of left ventricular (LV) stiffness. We therefore investigated the influence of LV stiffness, determined by pressure-volume loop analysis obtained by conductance catheterization, on exercise capacity in HFNEF. Methods and Results. 27 HFNEF patients who showed LV diastolic dysfunction in pressure-volume (PV) loop analysis performed symptom-limited cardiopulmonary exercise testing (CPET) and were compared with 12 patients who did not show diastolic dysfunction in PV loop analysis. HFNEF patients revealed a lower peak performance (P = .046), breathing reserve (P = .006), and ventilation equivalent for carbon dioxide production at rest (P = .002). LV stiffness correlated with peak oxygen uptake (r = −0.636, P < .001), peak oxygen uptake at ventilatory threshold (r = −0.500, P = .009), and ventilation equivalent for carbon dioxide production at ventilatory threshold (r = 0.529, P = .005). Conclusions. CPET parameters such as peak oxygen uptake, peak oxygen uptake at ventilatory threshold, and ventilation equivalent for carbon dioxide production at ventilatory threshold correlate with LV stiffness. Increased LV stiffness impairs exercise capacity in HFNEF.

CT Bronchoscopic Simulation for Guiding Transbronchial Needle Aspiration of Extramural Mediastinal and Hilar Lesions: Initial Clinical Results

PURPOSE To compare the yield of transbronchial needle aspiration (TBNA) with conventional orientation by using axial computed tomographic (CT) sections and that of TBNA with CT bronchoscopic simulation guidance for diagnosis of bronchoscopically occult extramural mediastinal and hilar lesions and the hit rates of both methods with regard to lesion number, size, and location in an intraindividual setting. MATERIALS AND METHODS During this institutional review board-approved study, 28 patients with 50 bronchoscopically invisible lesions (mean short-axis diameter, 14 mm +/- 5 [standard deviation]; range, 6-38 mm) of the mediastinum and hilum gave informed consent and underwent TBNA. For CT bronchoscopic simulation, the target was displayed at virtual bronchoscopy to localize the best needle insertion point for TBNA. Each lesion was initially punctured with knowledge of axial CT sections only, followed by a second pass after reviewing CT bronchoscopic simulation. A hit was defined when specific material (eg, lymphatic or malignant cells) was obtained. Both methods were compared with respect to lesion size and location of successful punctures. RESULTS With orientation by using CT bronchoscopic simulation, 29 of 50 lesions were successfully punctured, whereas only 15 lesions were hit with orientation by using axial CT sections (P < .05). Hit rate of CT bronchoscopic simulation was superior to conventional orientation independent of lesion size and location. CONCLUSION Orientation by using CT bronchoscopic simulation helps improve guidance for TBNA of bronchoscopically invisible lesions of the mediastinum and the hilum, increases the hit rate, and may be a helpful tool for less experienced bronchoscopists. SUPPLEMENTAL MATERIAL http://radiology.rsnajnls.org/cgi/content/full/250/3/923/DC1.

Enteroviral and immune mediated myocarditis in SCID mice.

Severe combined immune deficiency (SCID) mice have been used as an animal model to study both the direct cytopathic effect of enteroviruses on the heart in the absence of an effective immune system and to investigate the role of immune mediated processes in the pathogenesis of human myocarditis.The infection of SCID mice with coxsackievirus B3 resulted in severe myocarditis with very high titers of the virus in the myocardium and severe necrosis of myocytes. This direct cytopathic effect caused an impairment of the myocardial function and resulted in a high mortality rate of the infected animals.For the study of the immune mechanisms in human myocarditis, peripheral blood leukocytes of patients with myocarditis, having an impaired left ventricular function without viral persistence in the myocardium, were transferred into SCID mice. As controls peripherals blood leukocytes of normal donors were used. At 60 days after transfer, human immunoglobulines could be demonstrated in the peripheral blood of the SCID mice, however, human autoantibodies against the adenine nucleotide translocator, a myocardial autoantigen, were only present in the animals receiving peripheral blood leukocytes from patients with myocarditis. Cellular infiltrates of human leukocytes in the myocardium and an impaired left ventricular function were also only observed in animals reconstituted with peripheral blood leukocytes from patients. These effects were T cell dependent as shown by differential transfer.These results are of interest for the treatment of human myocarditis, suggesting the avoidance of an immunosuppressive therapy in acute or chronic myocarditis with viral persistence to prevent a direct cytophatic effect in the absence of an effective immune system. However, in the setting of a chronic, (auto-)immunological myocarditis with the proven absence of entero- or adneoviral sequences an immunomodulatory therapy seems to be effective and safe.ZusammenfassungDie Bedeutung einer enteroviralen Infektion sowie einer resultierenden Immunreaktion ist immer noch Gegenstand der Forschung in der Pathogenese der humanen Myokarditis. Mäuse mit einer kombinierten Immundefizienz (“severe combined immundeficiency”, SCID-Mäuse), die keinen eigenen funktionstüchtigen peripheren B- und T-Lymphozyten besitzen, wurden im Tiermodell verwendet, um den direkten zytopathischen Effekt von Enteroviren auf Herzmuskelzellen in der Abwesenheit eines effektiven Immunsystems zu untersuchen. Außerdem kann dieses Tiermodell verwendet werden, um die Rolle von immunologischen und autoimmunologischen Prozessen in der Pathogenese der humanen Myokarditis zu analysieren.Die Infektion von SCID-Mäusen mit Coxsackie-B3-Viren führt zu einer ausgeprägten Myokarditis bei sehr hohen Virustitern im Myokardgewebe und schweren Myokardzellnekrosen. Dieser direkte zytopathische Effekt verursacht eine Einschränkung der myokardialen Pumpfunktion und führte zu einer hohen Mortalitätsrate in den infizierten Tieren, während immunkompetente Mäuse praktisch keine Mortalität aufweisen.Zur Untersuchung der Immunmechanismen bei der humanen Myokarditis wurden periphere Blutleukozyten von Patienten mit Myokarditis, die eine eingeschränkte linksventrikuläre Funktion, jedoch keine Viruspersistenz im Myokard aufwiesen, auf SCID-Mäuse übertragen. Als Kontrollen dienten die peripheren Blutleukozyten von gesunden Personen. 60 Tage nach dem Transfer fanden sich humane Immungloboline im peripheren Blut der SCID-Mäuse. Humane Autoantikörper gegen den Adenin-Nukleotid-Translokator, ein myokardiales Autoantigen, fanden sich hingegen nur bei den Tieren, die periphere Blutleukozyten von Patienten mit Myokarditis erhalten hatten. Zelluläre Infiltrate von humanen Leukozyten im Myokard und eine Einschränkung der linksventrikulären Funktion (verminderte Druckanstiegsgeschwindigkeit) lagen ebenso nur bei den SCID-Mäusen vor, die periphere Blutleukozyten von Patienten mit Myokarditis erhalten hatten. Die Tiere wiesen jedoch keinen Anhalt für eine Graft-versus-Host-Reaktion auf, wie die Untersuchung von verschiedenen anderen Geweben ergab. Der Transfer der humanen Myokarditis in SCID-Mäusen ist ein T-Zell-abhängiger Prozess, wie ein entsprechender differenzieller Transfer von nur CD4-positiven oder CD4-depletierten peripheren Blutleukozyten zeigte.Diese Untersuchungen dürften für die Therapie der humanen Myokarditis von Bedeutung sein. Diese Experimente legen nahe, dass im Rahmen der Myokarditis des Menschen vor allem im Stadium der akuten Erkrankung auf eine immunsuppressive Therapie verzichtet werden sollte, um eine Schwächung des Immunsystems und damit eine erhöhte Virämie und somit auch eine Verstärkung des direkten zytopathischen Effektes auf die Herzmuskelzellen zu verhindern. Aber auch im chronischen Stadium der Erkrankung sollte eine Viruspersistenz durch Entnahme von Myokardbiopsien mit entsprechender molekularbiologischer Analyse (Polymerasekettenreaktion und/oder In-situ-Hybridisierung für Entero- bzw. Adenoviren) untersucht werden, bevor eine immunsuppressive Therapie erwogen wird. In diesem Stadium der Erkrankung sollte bei nachgewiesener Viruspersistenz vielmehr möglicherweise eine Therapie mit subkutanen Gaben von Interferon initiiert werden, wie Untersuchungen unserer eigenen Arbeitsgruppe zwischenzeitlich nahelegen.Zum anderen sprechen die Befunde dieses Tiermodells auch dafür, dass es sich bei der Myokarditis des Menschen im chronischen Stadium der Erkrankung bei Ausschluss einer Viruspersistenz um einen chronischen autoimmunologischen Prozess handelt, der einer immunmodulatorischen Therapie zugeführt werden sollte. Nur durch eine differenzierte histologische, immunhistologische und molekularbiologische Diagnostik ist es jedoch möglich, eine Differenzierung des akuten virologischen Stadiums der Erkrankung von einem chronischen, immunologisch bedingten Stadium vorzunehmen und dementsprechend eine sinnvolle kausale Therapie durchzuführen.

Virtual bronchoscopy guidance system for transbronchial needle aspiration

A system for planning transbronchial needle aspiration (TBNA) based on high-resolution chest CT is presented, comprising 2D axial, coronal or sagittal views and a 3D perspective intra-luminal view of the airways. The biopsy site can be defined interactively on the 2D views, and is displayed as 3D object across the translucent bronchial wall. Reference points can be placed on anatomical landmarks like the carina, which allows measuring 3D distances to viewpoints or to other landmarks. Orientation of the targets can be estimated based on a consistent orientation of the virtual endoscopic view. The system can be used as a pre-interventional planning tool, or simultaneously during the biopsy, in order to select the optimal needle insertion points. The system does not provide registration between the virtual and the real images, and does not require special hardware for tracking or any modifications of the bronchoscope. A phantom study comprising three bronchoscopists with different levels of experience showed a significant increase in yield compared to the traditional procedure based on axial CT images alone.

Computed tomography-bronchoscopic simulation for guiding transbronchial fine needle aspiration of extramural targets: a phantom study.

Objectives:Extramural paratracheal/-bronchial tumors of the mediastinum and the hilum that cannot be seen in bronchoscopy constitute a particular challenge for transbronchial fine needle aspiration cytology. A software prototype was developed as a guidance tool to visualize extramural targets on computed tomography (CT)-bronchoscopy. A phantom study was conducted to evaluate this guidance tool. Material and Methods:For CT-bronchoscopic simulation extramural targets are visualized behind the semitransparent wall in the endoluminal view. An airway phantom with 16 targets was examined by 3 bronchoscopists. In a first pass the targets were bronchoscopically punctured in the conventional way only with knowledge of axial CT-sections. In a second pass guidance by CT-bronchoscopic simulation was used. A postinterventional CT scan of the phantom was conducted to analyze the spatial relationship between the marked puncture sites and the targets. The punctures were classified in hits and failed punctures due to deviation in distance and angle. Results:The total hit rate of the 3 operators was significantly higher with CT-bronchoscopic simulation (32 of 48) than with the conventional method (14 of 48; P < 0.01). Concerning the failed punctures the deviation in distance and angle was significantly smaller with CT-bronchoscopic simulation (P < 0.01, P < 0.05, respectively). Conclusion:CT-bronchoscopic simulation significantly increased hit rate of bronchoscopic punctures of extramural lesions compared with conventional orientation using axial CT-sections in this phantom study. These results suggest that CT-bronchoscopic simulation might be a valuable tool for increasing yield and accuracy of bronchoscopic transbronchial fine needle aspiration in patients with mediastinal and hilar masses that are invisible for conventional bronchoscopy.