TY  - THES
A1  - Schlegel, Nicolas
T1  - Reaktive Veränderungen von Rückenmark und Nervenwurzeln nach dorsaler Rhizotomie sowie Ausriss und Replantation der Vorderwurzel im Segment C7 mit Applikation neurotropher Faktoren CNTF und BDNF
T1  - Reactive changes of spinal cord and nerve roots after dorsal rhizotomy, avulsion and replantation of C7 ventral roots with application of neurotrophic factors CNTF and BDNF
N2  - Als Therapieversuch bei Plexusläsionen wird die Replantation ausgerissener Vorderwurzelfasern durchgeführt. Voraussetzung für die erfolgreiche Regeneration von Motoneuronaxonen sind 1. Überleben einer ausreichenden Anzahl von Motoneuronen 2. erfolgreiche Wiederherstellung der Kontuität ausgerissener Axone mit dem Rückenmark und 3. funktionelle Hochwertigkeit regenerierter Axone. Neurotrophe Faktoren können Überleben und Regenerationsfähigkeit von Motoneuronen fördern. Gegenstand der vorliegenden Arbeit war die Analyse des Einflusses von CNTF und BDNF auf die Regeneration von Motoneuronaxonen nach Ausriss und Replantation im Segment C7 nach einer Überlebenszeit von 3 Wochen bzw. 6 Monaten. Vervollständigt wurden diese Untersuchungen durch detaillierte morphologische Analysen von Spinalganglien, durchtrennter Hinterwurzel und verletztem Hinterhorn. In verschiedenen Gruppen von adulten Kaninchen wurden CNTF, BDNF, oder beide Faktoren auf die ventrolaterale Replantationsstelle appliziert, Kontrollen wurden ohne Faktor belassen (n>5). Die Überlebenszeit der Versuchstiere lag bei 3 Wochen (n=3 Kontrollen) und 6 Monaten (n=27). Aus dem perfundiertem Gewebe wurden Semidünnschnitte durch Vorderwurzel/Spinalganglien und Kryostatserienschnitte durch das Segment C7 angefertigt. DiI-Fluoreszenztracing, Markscheidenfärbung, eine modifizierte Klüver-Barrera-Färbung der Kryostatschnitte sowie eine Touloidinblaufärbung der Semidünnschnitte ermöglichte die morphologische und morphometrische Analyse des Gewebes. Die Anzahl der überlebenden Motoneurone lag nach sechs Monaten bei allen Versuchsgruppen bei etwa 30%. Fluoreszenz-Tracing und Markscheidenfärbungen von Serienschnitten zeigten, dass Axone sowohl über die ursprünglichen ventralen Austrittstellen als auch über die ventrolaterale Replantationsstelle das Rückenmark verließen und im Bereich des Spinalganglions eine kompakte Vorderwurzel bildeten. Ventral austretende Axone zeigten signifikant größere Durchmesser als lateral austretende. Ausmaß und Art der Regeneration waren interindividuell unterschiedlich, die besten Ergebnisse zeigte die Replantation nah am ursprünglichen Austrittsort der Vorderwurzel. Unterschiede zwischen den Gruppen waren nicht deutlich. In Semidünnschnitten durch die regenerierte Vorderwurzel fanden sich nach drei Wochen kaum intakte, myelinisierte Axone, nach sechs Monaten war die Zahl der Axone auf etwa 45% der Zahl der gesunden Seite angestiegen. Regenerierte Axone waren dünn, typische Motoneuronaxone stellten nur einen kleinen Teil der regenerierten Axone. Gruppenunterschiede fanden sich im Axon-Myelinverhältnis, das bei Kontrollen der replantierten Seiten signifikant erniedrigt war. Diese Erniedrigung war noch vorhanden, jedoch nicht mehr signifikant bei Tieren, die mit CNTF- und BDNF-behandelt wurden. Die replantierten Vorderwurzeln der CNTF+BDNF-Gruppe zeigte überwiegend eine signifikant bessere Myelinisierung als die replantierten Kontrollen. An der früheren Hinterwurzeleintrittszone am Rückenmark wurden in Tieren mit geringem Verletzungsausmaß kleine ZNS-Gewebsprotrusionen beobachtet, in denen sich myelinisierte Axone befanden. Diese Axone zeigten eine Wachstumsrichtung in die Peripherie, was auf eine Sprossung der sensorischen Rückenmarksneurone schließen lässt. Innerhalb des Spinalganglions waren Neuron- und Axondichte auf den verletzten Seiten nicht wesentlich verändert. Eine leichte Abnahme des relativen Anteils großer Neurone und Axone wurde in den verletzten Seiten der Kontrollgruppe beobachtet. Für Axone war diese Abnahme statistisch signifikant. Im Gegensatz dazu war dies in Tieren, die mit neurotrophen Faktoren behandelt wurden, nicht zu beobachten. Bei allen Tieren zeigte sich ein beträchtliches Auswachsen von Hinterwurzelaxonen aus dem Spinalganglion. Diese Axone fanden keine spontane Verbindung mit dem proximalen Rest der Wurzel, sondern waren durch Bindegewebe eingehüllt. Bei etwa der Hälfte der Tiere zeigte sich, dass einer Untergruppe dieser Axone in Richtung des Narbengewebes der replantierten Vorderwurzel gewachsen war und über Defekte in der Bindegewebshülle teilweise sogar in die Vorderwurzel einwuchsen. Ein möglicher Einfluss der applizierten neurotrophen Faktoren auf das quantitative Regenerationsergebnis scheint also in diesem Modell gering zu sein. Auf eine qualitative Verbesserung deutet die Normalisierung des Axon-Myelinverhältnisses großer regenerierter Axone bei Kombinationsbehandlung hin. Die im vorliegenden Modell beträchtliche Regenerationskapazität der Hinterwurzel scheint bisher unterschätzt worden zu sein. Das unerwartete Einwachsen von Hinterwurzelaxonen in die Vorderwurzel könnte mit einer funktionellen Beeinträchtigung der regenerierten Vorderwurzel verbunden sein.
N2  - Treatment of brachial plexus lesions is attempted by surgical replantation of avulsed nerve roots. Prerequisites for successful regeneration of motoneuron axons are 1. survival of a large number of motoneurons, 2. restoration of connectivity between avulsed nerve roots and spinal cord and 3. high quality of regenerated axons. Regeneration and survival of motoneurons can be supported by neurotrophic factors. In the present study, the influence of CNTF and BDNF on regeneration of motoneurons after C7 ventral root avulsion and replantation after 3 weeks and 6 months was analysed. Additionally, detailed morphological analyses of dorsal root ganglia (DRG), severed dorsal roots and injured dorsal horns were performed. In adult rabbits C7 dorsal roots were severed, ventral roots were avulsed and replanted ventrolaterally. CNTF, BDNF, or both was applied to the replantation site, controls were replanted without application of neurotrophic factors (n>5). After 3 weeks (n= 3 controls) and 6 months (n= 27) after avulsion and replantation semi-thin sections of ventral roots and DRGs as well as cryostat serial sections from C7 spinal cord segment were prepared. DiI-fluorescence tracing, myelin-sheath staining, modified Klüver-Barrera staining of cryostat section and touloidinblue staining of semi-thin sections served for morphological and quantitative analyses. Six months after lesion, a survival of 30% of the C7 motoneurons was found without differences between the experimental groups. Retrograde fluorescent tracing and histological analysis documented that many axons had regrown through the original ventral exit zones or had exited the spinal cord at the lateral replantation site. However, many laterally exiting axons had not grown out directly from the ventral horn through the lateral white matter but had elongated vertically before leaving the spinal cord. The mean axonal diameter was significantly higher in regenerated axons that had exited through the original ventral exit zones in comparison with axons which had grown out laterally. Application of BDNF and/or CNTF did not show any effects on the pathways of regeneration into the replanted root. Three weeks after ventral root avulsion and replantation the number of axons was rare. After six months, the number of myelinated axons increased to 45% compared to unlesioned sides. Regenerated axons were mainly of small caliber with few axons showing typical properties of motoneuron axons. In controls myelination was significantly reduced compared to the unlesioned sides. This was not observed after CNTF, BDNF and CNTF+BDNF treatment. In CNTF+BDNF treated animals myelination was significantly increased compared to replanted controls in the majority of cases. At the dorsal root entry zone, small myelinated axons extended into central tissue protrusions, in cases with well-preserved morphology. This suggested sprouting of spinal neuron processes into the central dorsal root remnant. In lesioned DRGs, the density of neurons and myelinated axons was not significantly altered, but a slight decrease in the relative frequency of large neurons and an increase of small myelinated axons was noted (significant for axons). Unexpectedly, differences in the degree of these changes were found between control and neurotrophic factor-treated animals. Central axons of DRG neurons formed dorsal root stumps of considerable length which were attached to fibrous tissue surrounding the replanted ventral root. In cases where gaps were apparent in dorsal root sheaths, a subgroup of dorsal root axons entered this fibrous tissue. Continuity of sensory axons with the spinal cord was never observed. Some axons coursed ventrally in the direction of the spinal nerve. In summary, the number of surviving motoneurons and regenerating axons appeared not to be influenced by a single- dose application of neurotrophic factors in this model. However, improvement of myelination indicated that the quality of regeneration can be increased especially by CNTF+BDNF- treatment. Moreover, the considerable capacity of dorsal root regeneration we observed in this study has possibly been underestimated previously. The unexpected ingrowth of dorsal root axons into the regenerated ventral roots could be harmful for ventral root regeneration.
KW  - Nervenregeneration
KW  - Neurotropher Faktor
KW  - Plexus brachialis
KW  - Armplexusverletzung
KW  - Ciliary neurotrophic factor
KW  - Brain-derived neurotrophic factor
KW  - Nervenwurzelausriss
KW  - Nervenwurzelreplantation
KW  - nerve regneration
KW  - nerve root avulsion
KW  - ventral root replantation
KW  - neurotrophic factors
KW  - rhizotomy
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-25325
ER  - 
TY  - JOUR
A1  - Reschke, Moritz
A1  - Salvador, Ellaine
A1  - Schlegel, Nicolas
A1  - Burek, Malgorzata
A1  - Karnati, Srikanth
A1  - Wunder, Christian
A1  - Förster, Carola Y.
T1  - Isosteviol sodium (STVNA) reduces pro-inflammatory cytokine IL-6 and GM-CSF in an in vitro murine stroke model of the blood–brain barrier (BBB)
JF  - Pharmaceutics
N2  - Early treatment with glucocorticoids could help reduce both cytotoxic and vasogenic edema, leading to improved clinical outcome after stroke. In our previous study, isosteviol sodium (STVNA) demonstrated neuroprotective effects in an in vitro stroke model, which utilizes oxygen-glucose deprivation (OGD). Herein, we tested the hypothesis that STVNA can activate glucocorticoid receptor (GR) transcriptional activity in brain microvascular endothelial cells (BMECs) as previously published for T cells. STVNA exhibited no effects on transcriptional activation of the glucocorticoid receptor, contrary to previous reports in Jurkat cells. However, similar to dexamethasone, STVNA inhibited inflammatory marker IL-6 as well as granulocyte-macrophage colony-stimulating factor (GM-CSF) secretion. Based on these results, STVNA proves to be beneficial as a possible prevention and treatment modality for brain ischemia-reperfusion injury-induced blood–brain barrier (BBB) dysfunction.
KW  - IL-6
KW  - ischemia
KW  - isosteviol sodium (STVNA)
KW  - dexamethasone
KW  - glucocorticoid receptor
KW  - cerebEND
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-286275
SN  - 1999-4923
VL  - 14
IS  - 9
ER  - 
TY  - JOUR
A1  - Wiegering, Armin
A1  - Korb, Doreen
A1  - Thalheimer, Andreas
A1  - Kämmerer, Ulrike
A1  - Allmanritter, Jan
A1  - Matthes, Niels
A1  - Linnebacher, Michael
A1  - Schlegel, Nicolas
A1  - Klein, Ingo
A1  - Ergün, Süleyman
A1  - Germer, Christoph-Thomas
A1  - Otto, Christoph
T1  - E7080 (Lenvatinib), a Multi-Targeted Tyrosine Kinase Inhibitor, Demonstrates Antitumor Activities Against Colorectal Cancer Xenografts
N2  - Clinical prognosis of metastasized colorectal carcinoma (CRC) is still not at desired levels and novel drugs are needed. Here, we focused on the multi-tyrosine kinase inhibitor E7080 (Lenvatinib) and assessed its therapeutic efficacy against human CRC cell lines in vitro and human CRC xenografts in vivo. The effect of E7080 on cell viability was examined on 10 humanCRCcell lines and humanendothelial cells (HUVEC). The inhibitory effect of E7080 on VEGF-induced angiogenesis was studied in an ex vivo mouse aortic ring angiogenesis assay. In addition, the efficacy of E7080 against xenografts derived fromCRC cell lines and CRC patient resection specimenswithmutated KRASwas investigated in vivo. Arelatively low cytotoxic effect of E7080 on CRC cell viabilitywas observed in vitro. Endothelial cells (HUVEC)weremore susceptible to the incubation with E7080. This is in line with the observation that E7080 demonstrated an anti-angiogenic effect in a three-dimensional ex vivo mouse aortic ring angiogenesis assay. E7080 effectively disrupted CRC cell-mediated VEGF-stimulated growth of HUVEC in vitro. Daily in vivo treatment with E7080 (5 mg/kg) significantly delayed the growth of KRAS mutated CRC xenografts with decreased density of tumor-associated vessel formations and without tumor regression. This observation is in line with results that E7080 did not significantly reduce the number of Ki67-positive cells in CRC xenografts. The results suggest antiangiogenic activity of E7080 at a dosage thatwas well tolerated by nudemice. E7080 may provide therapeutic benefits in the treatment of CRC with mutated KRAS.
KW  - Chirurgie
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-111165
ER  - 
TY  - JOUR
A1  - Chen, Wen
A1  - Gaßner, Birgit
A1  - Börner, Sebastian
A1  - Nikolaev, Viacheslav O.
A1  - Schlegel, Nicolas
A1  - Waschke, Jens
A1  - Steinbronn, Nadine
A1  - Strasser, Ruth
A1  - Kuhn, Michaela
T1  - Atrial natriuretic peptide enhances microvascular albumin permeability by the caveolae-mediated transcellular pathway
JF  - Cardiovascular Research
N2  - Aims 
Cardiac atrial natriuretic peptide (ANP) participates in the maintenance of arterial blood pressure and intravascular volume homeostasis. The hypovolaemic effects of ANP result from coordinated actions in the kidney and systemic microcirculation. Hence, ANP, via its guanylyl cyclase-A (GC-A) receptor and intracellular cyclic GMP as second messenger, stimulates endothelial albumin permeability. Ultimately, this leads to a shift of plasma fluid into interstitial pools. Here we studied the role of caveolae-mediated transendothelial albumin transport in the hyperpermeability effects of ANP.
Methods and results 
Intravital microscopy studies of the mouse cremaster microcirculation showed that ANP stimulates the extravasation of fluorescent albumin from post-capillary venules and causes arteriolar vasodilatation. The hyperpermeability effect was prevented in mice with conditional, endothelial deletion of GC-A (EC GC-A KO) or with deleted caveolin-1 (cav-1), the caveolae scaffold protein. In contrast, the vasodilating effect was preserved. Concomitantly, the acute hypovolaemic action of ANP was abolished in EC GC-A KO and Cav-1−/− mice. In cultured microvascular rat fat pad and mouse lung endothelial cells, ANP stimulated uptake and transendothelial transport of fluorescent albumin without altering endothelial electrical resistance. The stimulatory effect on albumin uptake was prevented in GC-A- or cav-1-deficient pulmonary endothelia. Finally, preparation of caveolin-enriched lipid rafts from mouse lung and western blotting showed that GC-A and cGMP-dependent protein kinase I partly co-localize with Cav-1 in caveolae microdomains.
Conclusion 
ANP enhances transendothelial caveolae-mediated albumin transport via its GC-A receptor. This ANP-mediated cross-talk between the heart and the microcirculation is critically involved in the regulation of intravascular volume.
KW  - caveolin-1
KW  - microvessel permeability
KW  - atrial natriuretic peptide
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-126562
N1  - Lizenzhinweis: The online version of this article has been published under an open access model. Users are entitled to use, reproduce, disseminate, or display the open access version of this article for noncommercial purposes provided that the original authorship is properly and fully attributed; the Journal, Learned Society and Oxford University Press are attributed as the original place of publication with correct citation details given; if an article is subsequently reproduced or disseminated not in its entirety but only in part or as a derivative work this must be clearly indicated.
VL  - 93
IS  - 1
ER  -