TY  - THES
A1  - Langseder, Theresa Christina
T1  - Charakterisierung intestinaler Barriereveränderungen bei Ratten nach Roux-en-Y Magenbypass
T1  - Characterization of intestinal barrier changes in rats after Roux-en-Y gastric bypass
N2  - Die bariatrische Chirurgie ist momentan die einzige Therapieoption der morbiden Adipositas mit der eine langfristige Gewichtsreduktion erreicht werden kann. Unter den Operationsmethoden gilt der RYGB als eine der wirksamsten Behandlungen bezogen auf den Gewichtsverlust und die Verbesserung von Begleiterkrankungen wie dem Diabetes mellitus Typ 2. Darüber hinaus belegt eine wachsende Zahl an Veröffentlichungen, dass der RYGB den Zustand chronischer Entzündung, wie er typischerweise mit Adipositas einhergeht, verringern kann. Diese sogenannte Endotoxämie geht unter anderem mit einer gestörten Integrität der intestinalen Epithelbarriere einher. Ziel der vorliegenden Arbeit war es eine Analyse der Veränderungen von für die Darmbarriere wichtigen Junktionsproteinen vorzunehmen, um eine Grundlage für künftige mechanistische Untersuchungen zu schaffen. Dafür wurden die Veränderungen von Barriereproteinen in Vollwandresektaten des Duodenums, des Jejunums, des Ileums sowie des Kolons von Ratten, die einen RYGB erhalten hatten, mittels Western Blot Untersuchungen quantifiziert. Als Kontrollgruppe dienten schein-operierte Ratten. Es kam zu tiefgreifenden Veränderungen der analysierten Barriereproteine in den Vollwandresektaten. Interessanterweise unterschieden sich die Verteilungsmuster der Veränderungen der Barriereproteinte deutlich zwischen den einzelnen Darmregionen. Um herauszufinden, ob diese Veränderungen durch regionale Veränderungen der Mikroumgebung nach RYGB- Operation induziert wurden, wurden im reduktionistischen Zellkultursystem Stuhl- Transferexperimente durchgeführt. Caco2-Zellkulturen dienten hierbei als Modell für die intestinale epitheliale Barriere. Es wurden funktionelle Messungen und quantitative Analysen der Veränderungen der Barriereproteine der Zellkultur durchgeführt. Die Funktionsmessungen zeigten, dass der Inhalt des Duodenums, des Jejunums sowie des Kolons deutliche barrierestabilisierende Effekte auf die Caco2-Zellmonolayer hatte. Zudem zeigten sich tiefgreifende Veränderungen der untersuchten Barriereproteine. Zusammenfassend wurde in der vorliegenden Arbeit erstmals eine regionenspezfische Regulation der intestinalen Barriereproteine in Korrelation mit funktionellen Messungen nach RYGB nachgewiesen.
N2  - Bariatric surgery is currently the only treatment option for morbid obesity that can achieve long-term weight loss. Among surgical methods, RYGB is considered one of the most effective treatments in terms of weight loss and improvement of associated diseases such as type 2 diabetes mellitus. In addition, a growing number of publications demonstrate that RYGB can reduce the state of chronic inflammation typically associated with obesity. This so-called endotoxemia is associated with impaired integrity of the intestinal epithelial barrier. The aim of the present work was to perform an analysis of changes in junctional proteins which are important for the intestinal barrier in order to provide a basis for future mechanistic studies. For this purpose, the changes of barrier proteins in whole-wall resections of the duodenum, jejunum, ileum, and colon of rats that had received an RYGB were quantified by Western blot studies. Sham-operated rats served as the control group. Profound changes in the analyzed barrier proteins occurred in the whole-wall resectates. Interestingly, the distribution patterns of barrier protein changes differed markedly between intestinal regions. To determine whether these changes were induced by regional changes in the microenvironment after RYGB- surgery, stool transfer experiments were performed in the reductionist cell culture system. Caco2 cell cultures served here as a model for the intestinal epithelial barrier. Functional measurements and quantitative analyses of the changes in the cell culture barrier proteins were performed. The functional measurements showed that the contents of the duodenum, jejunum, as well as the colon had significant barrier-stabilizing effects on the Caco2 cell monolayers. In addition, profound changes in the barrier proteins examined were evident. In summary, the present work was the first to demonstrate region-specific regulation of intestinal barrier proteins in correlation with functional measurements by RYGB.
KW  - Operation
KW  - Pathogenese
KW  - RYGB
KW  - terminal bar
KW  - Schlussleistenkomplex
KW  - intestinal epithelial barrier
KW  - bariatric surgery
KW  - Endotoxämie
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-305756
ER  - 
TY  - THES
A1  - Fink, Nicolas Robin
T1  - Hält doppelt besser? Retrospektiver Vergleich zweier operativer Therapiestrategien kindlicher Unterarmfrakturen
T1  - Is two better than one? Retrospective comparison of two surgical treatment strategies of pediatric forearm fractures
N2  - Die hier vorliegende Untersuchung beschäftigt sich mit dem Vergleich zweier minimalinvasiver operativer Therapiestrategien der distalen Unterarmfraktur als häufigster Fraktur im Kindesalter. 
Für die vorliegende Studie erfolgte eine umfassende retrospektive Auswertung von 122 Fällen distaler kindlicher Unterarmfrakturen aus einem Zeitraum von elf Jahren, die in der kinderchirurgischen Abteilung des Universitätsklinikums Würzburg osteosynthetisch versorgt wurden. Ziel der Untersuchung war die Betrachtung der Epidemiologie des Verletzungsbildes und des Therapieerfolges in Abhängigkeit von der gewählten Osteosynthesetechnik. Die Kinder wurden dabei entweder allein durch eine Kirschner-Draht-Osteosynthese des Radius oder durch eine zusätzliche Fixierung der Ulna mittels elastisch stabiler intramedullärer Nagelung versorgt.
Durch beide Operationsstrategien konnte für die meisten Patientinnen und Patienten ein gutes Therapieergebnis erreicht werden. Hinsichtlich der Operations- und Hospitalisierungsdauer zeigte sich ein Vorteil für Kinder, die osteosynthetisch lediglich durch Kirschner-Drähte versorgt wurden. In anderen Studien beobachtete Komplikationen in Form sekundärer Dislokationen der Fraktur auch nach Osteosynthese oder Infektionen im Bereich der Drahtenden konnten im hier untersuchten Kollektiv seltener festgestellt werden.
Die vorliegende Untersuchung zeigt, dass, sofern die Indikation zur operativen Versorgung besteht, die Fixierung des Radius allein mittels Kirschner-Drähten eine adäquate Therapie distaler Frakturen von Ulna und Radius im Kindesalter darstellt. Von einer kombinierten Osteosynthese mittels Kirschner-Drähten und ESIN könnten besonders Patientinnen und Patienten profitieren, bei denen initial große Dislokationen der Fraktur, Begleitverletzungen des Arms oder eine Lokalisation im Bereich des diametaphysären Übergangs bestehen. Um diese Beobachtungen auch in größeren Kollektiven und prospektiv sowie randomisiert zu untersuchen, sind weitere Studien wünschenswert.
N2  - The present study deals with the comparison of two minimally invasive surgical treatment strategies of the distal forearm fracture as the most frequent fracture in childhood. 
The study shows a comprehensive retrospective evaluation of 122 cases of distal pediatric forearm fractures from a period of eleven years, which were treated osteosynthetically in the pediatric surgery department of the University Hospital of Würzburg. The aim of the study was to examine the epidemiology of the injury pattern and the therapeutic success in relation to the selected osteosynthesis technique. The children were treated either by Kirschner wire osteosynthesis of the radius alone or by additional fixation of the ulna using elastic stable intramedullary nailing.
Both surgical strategies resulted in a good therapeutic outcome for most patients. With regard to the duration of surgery and hospitalization, there was an advantage for children who were treated osteosynthetically with Kirschner wires only. Complications observed in other studies in the form of secondary dislocation of the fracture even after osteosynthesis or infections in the area of the wire ends were found less frequently in the present collective.
The present study shows that, if surgical treatment is indicated, fixation of the radius using Kirschner wires alone is an adequate therapy for distal fractures of the ulna and radius in childhood. Patients who initially have large dislocations of the fracture, concomitant injuries of the arm, or a localization in the area of the diametaphyseal transition could particularly benefit from a combined osteosynthesis using Kirschner wires and ESIN. Further studies are desirable to investigate these observations also in larger collectives, prospectively and randomized.
KW  - Unterarmbruch
KW  - Unterarmfraktur
KW  - ESIN
KW  - Kirschner-Draht
KW  - K-wire
KW  - ESIN
KW  - Forearm fracture
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-302604
ER  - 
TY  - THES
A1  - Nagel, Kathrin
T1  - Definition und Diagnostik des postoperativen Hypoparathyreoidismus nach Thyreoidektomie - ein systematischer Review und Metaanalyse
T1  - Definition and diagnosis of postsurgical hypoparathyroidism after thyroid surgery: systematic review and meta-analysis
N2  - Der postoperative Hypoparathyreoidismus (PH) stellt eine der häufigsten Komplikationen nach Schilddrüsenoperationen dar. Ziel dieses systematischen Reviews und Metaanalyse ist die Erarbeitung einer einheitlichen Definition sowie die Ermittlung des bestmöglichen Ansatzes für eine frühzeitige Detektion des PH. 

Nach Durchführung einer systematischen Literaturrecherche gemäß der PICo-Systematik unter Verwendung der Datenbanken Embase, Pubmed und der Cochrane Library, erfolgte die themenbezogene Aufarbeitung der eingeschlossenen Studien, sowie eine Bias-Bewertung und Metaanalyse geeigneter Arbeiten. 

Von 13.704 Artikeln konnten 188 in die weitere Analyse eingeschlossen werden. In diesen fanden sich sehr heterogene Definitionen des PH. Sowohl in der systematischen Analyse als auch in der Metaanalyse zeigte sich eine genauere Vorhersagekraft des PH durch eine postoperative im Vergleich zu einer intraoperativen PTH-Messung. Keiner der analysierten Zeiträume innerhalb des ersten postoperativen Tages (POD1) zeigte eine signifikante Überlegenheit in der Vorhersage eines PH. Die PTH- Schwellenwerte 10 bzw. 15 pg/ml können einen PH zuverlässig detektieren. Als Entscheidungsgrundlage zwischen den beiden Werten kann die untere Normwertgrenze des angewendeten Testverfahrens herangezogen werden. Bei präoperativer PTH-Abnahme nach Anästhesieeinleitung ist ein relativer PTH-Abfall von prä- nach postoperativ von 73 ± 11% prädiktiv für die Entwicklung eines PH. Die Bestimmung des Calciumspiegels an POD1 ist obligat und optimiert insbesondere die Erkennung einer biochemischen Hypokalzämie. 

Ein nicht nachweisbarer oder inadäquat niedriger postoperativer PTH-Spiegel im Zusammenhang mit einer biochemischen oder symptomatischen Hypokalzämie kann als einheitliche Definition des postoperativen Hypoparathyreoidismus vorgeschlagen werden. Die Messung des Parathormons sollte zwischen einer und sechs Stunden postoperativ, spätestens aber innerhalb von 24 Stunden erfolgen. Sowohl der Schwellenwert ≤ 15 pg/ml als auch ein relativer PTH-Abfall von prä- nach postoperativ sind zuverlässig in der Detektion gefährdeter Patienten.
N2  - Background: Postsurgical hypoparathyroidism (PH) is the most frequent complication after
thyroid surgery. The aim of this systematic review and meta-analysis is to summarize a
unifying definition of PH and to elucidate the best possible approach for early detection of
PH.

Methods: A systematic review of the literature according to the PICO framework using
Embase, PUBMED and the Cochrane library was carried out on 1 December 2021 followed
by analysis for risk of bias, data extraction and meta-analysis. All studies addressing the
definition of postoperative hypoparathyroidism and/or diagnostic approaches for early
detection and diagnosis were included. Case reports, commentaries, non-English articles,
book chapters and pilot studies and reviews were excluded.

Results: From 13 704 articles, 188 articles were eligible for inclusion and further analysis.
These articles provided heterogeneous definitions of PH. Meta-analysis revealed that
postoperative measurements of parathormone (PTH) levels have a higher sensitivity and
specificity than intraoperative PTH measurements to predict PH after thyroid surgery. None
of the timeframes analysed after surgery within the first postoperative day (POD1) was
superior to predict the onset of PH. PTH levels of less than 15 pg/ml and less than 10 pg/ml
are both reliable threshold levels to predict the postoperative onset of PH. A relative
reduction of mean (s.d.) PTH levels from pre- to postoperative values of 73 (+/- 11) per cent
may also be predictive for the development of PH. The estimation of calcium levels on POD1
are recommended.

Conclusion: PH is best defined as an undetectable or inappropriately low postoperative
PTH level in the context of hypocalcaemia with or without hypocalcaemic symptoms. PTH
levels should be measured after surgery within 24 h. Both threshold levels below 10 and 15
pg/ml or relative loss of PTH before/after thyroid surgery are reliable to predict the onset of
PH.
KW  - Hypoparathyreoidismus
KW  - Thyreoidektomie
KW  - postoperative Komplikationen
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-300083
ER  - 
TY  - THES
A1  - Kloos, Kerstin
T1  - Über die Effekte von Hyperthermie und Zytostatika auf die Tumorzellproliferation, Apoptose und Expression von Heat Shock Proteinen im Kolonkarzinom
T1  - Effects of hyperthermia and cytostatic drugs on tumor cell proliferation, apoptosis and expression of heat shock proteins in colon carcinoma
N2  - Die Kombination aus zytoreduktiver Chirurgie und einer anschließenden hyperthermen intraperitonealen Chemoperfusion (HIPEC) stellt sich als vielversprechende Therapiestrategie bei ausgesuchten Patienten mit Peritonealkarzinose, z. B. des kolorektalen Karzinoms, dar. Die intraperitoneale Chemoperfusion kombiniert eine lokale Hochdosis-Chemotherapie mit einer Hyperthermie. Hitzeschockproteinen (HSP) kommt dabei eine bedeutende Rolle zu, da sie infolge von zellulären Stressfaktoren wie Hitze oder Zytostatika-bedingter Chemotoxizität induziert werden. HSPs setzen Reparatur- und Zellschutzmechanismen in Gang und vermindern so in einzelnen überlebenden Tumorzellen möglicherweise den gewünschten Therapieerfolg der HIPEC. Ziel der Arbeit war es, mithilfe eines bereits etablierten in vitro HIPEC-Modells die Auswirkungen der äußeren Stressoren Hyperthermie und Zytostatika auf die Expression von Hitzeschockproteinen (HSP27, HSP70 und HSP90) in drei humanen Kolonkarzinomzelllinien zu untersuchen. Dazu wurden die Zelllinien HT29, SW480 und SW620 jeweils mit und ohne Zytostatika (Mitomycin C, MMC und Oxaliplatin, OXA) für eine Stunde drei verschiedenen Temperaturstufen von 37°C als Normothermie, 41°C und 43°C als Hyperthermie ausgesetzt und nach einer Regenerationszeit von 30 min, 24 h, 48 h und 72 h mit Hilfe von RT-qPCR-Analysen und Western Blots untersucht. Zudem wurden nach gleichem Ablauf Effekte der HIPEC auf die Tumorzellproliferation und Apoptose mittels Proliferationsmarkern Ki-67, PCNA und MTS-Tests sowie dem antiapoptotischen Protein Bcl-xL in in vitro Tumorzellansätzen sowie in ex vivo Patientenproben vor und nach HIPEC analysiert. Sowohl die einstündige Chemotherapie mit Mitomycin C oder Oxaliplatin unter hyperthermen Bedingungen als auch die isolierte Hyperthermiebehandlung führte im Vergleich zu normothermen Kontrollbedingungen bei 37°C zu einer signifikanten Überexpression der untersuchten HSPs in RTq-PCR-Analysenaller drei Kolonkarzinomzelllinien. Interessanterweise wurden vermehrte HSP Genexpressionsmuster noch drei Tage nach Behandlung beobachtet. Eine verstärkte Proteinexpression zeigte sich bestätigend insbesondere für HSP27 und HSP70 unter zytostatischer Behandlung mit MMC oder OXA und führte zu einer bis zu 3-fachen Expressionssteigerung wenn die Zellen hyperthermen Bedingungen ausgesetzt waren. Tumorzellen, die zuvor der hyperthermen Chemotherapie unterzogen wurden, zeigten interessanterweise zudem proliferative anstelle von anti-proliferativen Effekten. In durchgeführten MTS-Tests führte sowohl die Hyperthermie allein als auch die zusätzliche Zytostatikagabe zu einer deutlich erhöhten Zellviabilität im Vergleich zu normothermer Chemotherapie im Modellansatz. Übereinstimmend mit den Ergebnissen der MTS-Tests konnte eine Induktion der Proliferationsmarker PCNA und Ki-67 durch Hyperthermie und Chemotherapie auf Gen- und Proteinebene beobachtet werden. Im Falle von PCNA ließ sich eine verstärkte Proteinexpression in ex vivo Proben von Patienten nach klinisch durchgeführter HIPEC bestätigen. Zusätzliche Untersuchungen des anti-apoptotisch wirkenden Regulatorproteins Bcl-xL in in vitro Tumorzellansätzen sowie in ex vivo Proben von Patienten nach hyperthermer Chemotherapie, zeigten zudem eine deutlich gesteigerte Proteinexpression unter alleiniger Hyperthermie sowie insbesondere in Kombination mit Zytostatika. Durch die Induktion von HSP27, HSP70 und HSP90 infolge von hyperthermem und zytotoxischem Stress werden in überlebenden Zellen nach hyperthermer Chemotherapie, unerwünschte antiapopotische sowie proliferative Effekte im Sinne von Reparatur- und Zellschutzmechanismen induziert und nehmen negativen Einfluss auf den Therapieerfolg der HIPEC. Schlussfolgernd wäre der Einsatz von HSP-Inhibitoren um die beschriebenen, unerwünschten Zellmechanismen zu verhindern, zu überprüfen. Diese bieten eine interessante Möglichkeit die Effizienz der im klinischen Einsatz gängigen Zytostatika zu steigern und somit einen positiven Einfluss auf den Erfolg der Therapie und die Überlebenszeit von Patienten mit Peritonealkarzinose zu nehmen. Weiterführende Studien der eigenen Arbeitsgruppe mit kombinierten HSP70/HSP90-Inhibitoren zeigten bereits eine signifikant reduzierte Zellviabilität in Kolonkarzinomzellen, die zuvor der hyperthermen Chemotherapie unterzogen wurden.
N2  - The combination of cytoreductive surgery followed by hyperthermic intraperitoneal chemoperfusion (HIPEC) emerges as a promising therapeutic strategy in selected patients with peritoneal carcinomatosis, such as colorectal carcinoma. Intraperitoneal chemoperfusion combines local high-dose chemotherapy with hyperthermia. Heat shock proteins (HSPs) play an important role in this process, as they are induced as a result of cellular stress factors such as heat or cytostatic drug-induced chemotoxicity. HSPs induce repair and cell protection mechanisms and thus possibly reduce the desired therapeutic success of HIPEC in individual surviving tumor cells. The aim of this work was to investigate the effects of the external stressors hyperthermia and cytostatic drugs on the expression of heat shock proteins (HSP27, HSP70 and HSP90) in three human colon carcinoma cell lines using an already established in vitro HIPEC model. For this purpose, cell lines HT29, SW480, and SW620 were each exposed to three different temperature levels of 37°C as normothermia, 41°C, and 43°C as hyperthermia for one hour with and without cytostatic drugs (mitomycin C, MMC, and oxaliplatin, OXA). After a regeneration period of 30 min, 24 h, 48 h, and 72 h they were examined by RT-qPCR analysis and Western blots. In addition, following the same procedure, effects of HIPEC on tumor cell proliferation and apoptosis were analyzed using proliferation markers Ki-67, PCNA and MTS assays, and the anti-apoptotic protein Bcl-xL in in vitro tumor cell mounts as well as in ex vivo patient samples before and after HIPEC. Both, one-hour chemotherapy with mitomycin C or oxaliplatin under hyperthermic conditions and isolated hyperthermia treatment resulted in significant overexpression of the HSPs in RTq-PCR analyses of all three colon carcinoma cell lines compared with normothermic control conditions at 37°C. Interestingly, increased HSP gene expression patterns were still observed three days after treatment. Increased protein expression was confirmatory especially for HSP27 and HSP70 under cytostatic treatment with MMC or OXA and resulted in up to a 3-fold increase in expression when cells were exposed to hyperthermic conditions. Tumor cells previously subjected to hyperthermic chemotherapy also interestingly showed proliferative instead of anti-proliferative effects. In MTS assays performed, both hyperthermia alone and additional cytostatic administration resulted in significantly increased cell viability compared to normothermic chemotherapy in the model approach. Consistent with the results of the MTS assays, induction of the proliferation markers PCNA and Ki-67 by hyperthermia and chemotherapy was observed at the gene and protein levels. In the case of PCNA, increased protein expression could be confirmed in ex vivo samples from patients after clinically performed HIPEC. Additional investigations of the anti-apoptotic regulator protein Bcl-xL in in vitro tumor cell preparations as well as in ex vivo samples from patients after hyperthermic chemotherapy, also showed a significantly increased protein expression under hyperthermia alone as well as especially in combination with cytostatic drugs. The induction of HSP27, HSP70 and HSP90 as a result of hyperthermic and cytotoxic stress induces undesired anti-apopotic and proliferative effects in surviving cells after hyperthermic chemotherapy in terms of repair and cell protection mechanisms and has a negative impact on the therapeutic success of HIPEC. In conclusion, the use of HSP inhibitors to prevent the described undesired cellular mechanisms should be investigated. These offer an interesting opportunity to increase the efficiency of cytostatic drugs commonly used in clinical practice and thus have a positive influence on the success of therapy and survival time of patients with peritoneal carcinomatosis. Further studies of the own research group with combined HSP70/HSP90 inhibitors already showed a significantly reduced cell viability in colon carcinoma cells previously subjected to hyperthermic chemotherapy.
KW  - Dickdarmkrebs
KW  - Colonkrebs
KW  - Peritonealkarzinose
KW  - HIPEC
KW  - Kolonkarzinom
KW  - Hitzeschock-Proteine
KW  - Hypertherme Chemotherapie
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-327101
ER  - 
TY  - JOUR
A1  - Glaser, Kirsten
A1  - Kern, David
A1  - Speer, Christian P.
A1  - Schlegel, Nicolas
A1  - Schwab, Michael
A1  - Thome, Ulrich H.
A1  - Härtel, Christoph
A1  - Wright, Clyde J.
T1  - Imbalanced inflammatory responses in preterm and term cord blood monocytes and expansion of the CD14\(^+\)CD16\(^+\) subset upon toll-like receptor stimulation
JF  - International Journal of Molecular Sciences
N2  - Developmentally regulated features of innate immunity are thought to place preterm and term infants at risk of infection and inflammation-related morbidity. Underlying mechanisms are incompletely understood. Differences in monocyte function including toll-like receptor (TLR) expression and signaling have been discussed. Some studies point to generally impaired TLR signaling, others to differences in individual pathways. In the present study, we assessed mRNA and protein expression of pro- and anti-inflammatory cytokines in preterm and term cord blood (CB) monocytes compared with adult controls stimulated ex vivo with Pam3CSK4, zymosan, polyinosinic:polycytidylic acid, lipopolysaccharide, flagellin, and CpG oligonucleotide, which activate the TLR1/2, TLR2/6, TLR3, TLR4, TLR5, and TLR9 pathways, respectively. In parallel, frequencies of monocyte subsets, stimulus-driven TLR expression, and phosphorylation of TLR-associated signaling molecules were analyzed. Independent of stimulus, pro-inflammatory responses of term CB monocytes equaled adult controls. The same held true for preterm CB monocytes—except for lower IL-1β levels. In contrast, CB monocytes released lower amounts of anti-inflammatory IL-10 and IL-1ra, resulting in higher ratios of pro-inflammatory to anti-inflammatory cytokines. Phosphorylation of p65, p38, and ERK1/2 correlated with adult controls. However, stimulated CB samples stood out with higher frequencies of intermediate monocytes (CD14\(^+\)CD16\(^+\)). Both pro-inflammatory net effect and expansion of the intermediate subset were most pronounced upon stimulation with Pam3CSK4 (TLR1/2), zymosan (TR2/6), and lipopolysaccharide (TLR4). Our data demonstrate robust pro-inflammatory and yet attenuated anti-inflammatory responses in preterm and term CB monocytes, along with imbalanced cytokine ratios. Intermediate monocytes, a subset ascribed pro-inflammatory features, might participate in this inflammatory state.
KW  - neonatal immunology
KW  - inflammation
KW  - preterm infants
KW  - monocytes
KW  - cord blood
KW  - monocyte subsets
KW  - cytokines
KW  - Toll-like receptor signaling
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-311056
SN  - 1422-0067
VL  - 24
IS  - 5
ER  - 
TY  - THES
A1  - Knop, Juna-Lisa
T1  - Untersuchungen zur Bedeutung von Spaltprodukten des vaskulär endothelialen (VE-) Cadherin als Auslöser für die Schrankenstörung des Gefäßendothels
T1  - Characterisation of the endothelial barrier-disruptive effects of soluble vascular endothelial (sVE-) cadherin
N2  - Ein Schlüsselereignis, welches dem prognosebestimmenden Organversagen bei systemi-schen Entzündungsprozessen und Sepsis vorangeht, ist die Entwicklung einer mikrovas-kulären endothelialen Schrankenstörung. Das vaskuläre endotheliale (VE-) Cadherin als mechanischer Stabilisator der Endothelbarriere spielt dabei eine wichtige Rolle. In der Inflammation werden Spaltprodukte von VE-Cadherin (sVE-Cadherin) gebildet. Ge-genstand der vorliegenden Arbeit war die Untersuchung der Hypothese ob diese Spalt-produkte selbst an der Störung der endothelialen Barrierefunktion beteiligt sind. 
Es wurde hierfür humanes sVE-Cadherin bestehend aus den extrazellulären Domänen EC1-5 (sVE-CadherinEC1-5) generiert. In Messungen des transendothelialen elektrischen Widerstands (TER), mit Immunfluoreszenzfärbungen und Western Blot Analysen wird gezeigt, dass sVE-Cadherin dosisabhängig die Barriere Integrität in primären humanen dermalen Endothelzellen stört. Dies führt zu einer Reduktion von VE-Cadherin und den assoziierten Proteinen α-, γ- und δ-Catenin und ZO-1, die nach der Applikation von sVE-Cadherin an den Zellgrenzen reduziert sind. Die Interaktion zwischen VE-PTP und VE-Cadherin wird durch sVE-CadherinEC1-5 reduziert. Durch pharmakologische Hem-mung der Phosphataseaktivität von VE-PTP mittels AKB9778 wird der durch sVE-CadherinEC1-5-induzierte Verlust der Endothelbarriere aufgehoben. Dagegen zeigt die direkte Aktivierung von Tie-2 mittels Angiopoetin-1 keinen protektiven Effekt auf die durch sVE-CadherinEC1-5 gestörte Endothelbarriere. Weitere Analysen zeigen eine erhöh-te Expression von GEF-H1 durch sVE-CadherinEC1-5. Diese ist ebenfalls durch AKB9778 hemmbar. 
Zusätzlich zu diesen Untersuchungen wurden die Konstrukte EC1-4 und EC3-5 in ver-schiedene Vektoren kloniert, um zu bestimmen, ob die extrazelluläre Domäne 5 von VE-Cadherin die dominante Rolle bei den sVE-Cadherin-vermittelten Effekten spielt. 
Zusammenfassend zeigen diese Untersuchungen zum ersten Mal, dass sVE-CadherinEC1-5 unabhängig von proinflammatorischen Auslösern über die Aktivierung des VE-PTP/RhoA-Signalweges den Zusammenbruch der Endothelbarriere mitversursacht. Dies stellt einen neuen pathophysiologischer Mechanismus dar, der zum Gesamtverständnis der entzündungsinduzierten Barriereveränderungen des Endothels beiträgt.
N2  - A key prognostic event preceding organ failure in sepsis and systemic inflammatory pro-cesses is dysfunction of the microvascular endothelial barrier. The transmembrane pro-tein vascular endothelial (VE-) cadherin is an important prerequisite to stabilize endothe-lial barrier. VE-cadherin is cleaved under inflammatory conditions which results in the release of soluble VE-cadherin (sVE-cadherin). The main hypothesis of this thesis is to investigate whether sVE-cadherin itself directly disrupts the endothelial barrier in the absence of proinflammatory stimuli.
Human sVE-cadherin consisting of extracellular domains EC1-5 (sVE-cadherinEC1-5) was generated and applied onto primary human dermal endothelial cells (HDMECs) for structural and functional analysis. Measurements of transendothelial electrical resistance (TER) and 4 kDa FITC-dectran flux revealed that sVE-cadherinEC1-5 dose-dependently disrupts endothelial barrier integrity. This was confirmed by immunostaining and im-munoblotting analysis which showed that sVE-cadherinEC1-5 treatment reduced overall levels of VE-cadherin and the associated proteins α-, γ- and δ-catenin and ZO-1 as well as their distribution at the cell border of HDMECs. sVE-cadherinEC1-5 treatment reduced the interaction between the phosphatase VE-PTP and VE-cadherin. Accordingly, phar-macological inhibition of VE-PTP using AKB9778 reversed sVE-cadherinEC1-5-induced endothelial barrier loss. Further analysis showed that the increased expression of GEF-H1 by sVE-cadherinEC1-5 is also attenuated by AKB9778. In addition to these studies, the constructs EC1-4 and EC3-5 were cloned into different vectors to determine wheth-er the extracellular domain 5 of VE-cadherin plays the dominant role in sVE-cadherin-mediated effects.
In summary, these studies show for the first time that sVE-cadherinEC1-5 actively con-tributes to breakdown of the endothelial barrier independently of proinflammatory stim-uli via activation of the VE-PTP/RhoA signaling pathway. This represents a new patho-physiological mechanism that adds to the understanding of inflammation-induced endo-thelial barrier changes.
KW  - Endothel
KW  - Sepsis
KW  - Cadherine
KW  - Proteintyrosinphosphatase
KW  - Rho-Kinasen
KW  - VE-Cadherin
KW  - VE-PTP
KW  - RhoA
KW  - ve-cadherin
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-344687
ER  - 
TY  - JOUR
A1  - Schmitz, Sophia M.
A1  - Storms, Sebastian
A1  - Koch, Alexander
A1  - Stier, Christine
A1  - Kroh, Andreas
A1  - Rheinwalt, Karl P.
A1  - Schipper, Sandra
A1  - Hamesch, Karim
A1  - Ulmer, Tom F.
A1  - Neumann, Ulf P.
A1  - Alizai, Patrick H.
T1  - Insulin resistance is the main characteristic of metabolically unhealthy obesity (MUO) associated with NASH in patients undergoing bariatric surgery
JF  - Biomedicines
N2  - (1) Background: Metabolically healthy obesity (MHO) is a concept that applies to obese patients without any elements of metabolic syndrome (metS). In turn, metabolically unhealthy obesity (MUO) defines the presence of elements of metS in obese patients. The components of MUO can be divided into subgroups regarding the elements of inflammation, lipid and glucose metabolism and cardiovascular disease. MUO patients appear to be at greater risk of developing non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) compared to MHO patients. The aim of this study was to evaluate the influence of different MUO components on NAFLD and NASH in patients with morbid obesity undergoing bariatric surgery. (2) Methods: 141 patients undergoing bariatric surgery from September 2015 and October 2021 at RWTH Aachen university hospital (Germany) were included. Patients were evaluated pre-operatively for characteristics of metS and MUO (HbA1c, HOMA, CRP, BMI, fasting glucose, LDL, TG, HDL and the presence of arterial hypertension). Intraoperatively, a liver biopsy was taken from the left liver lobe and evaluated for the presence of NAFLD or NASH. In ordinal regression analyses, different factors were evaluated for their influence on NAFLD and NASH. (3) Results: Mean BMI of the patients was 52.3 kg/m\(^2\) (36–74.8, SD 8.4). Together, the parameters HbA1c, HOMA, CRP, BMI, fasting glucose, LDL, TG, HDL and the presence of arterial hypertension accounted for a significant amount of variance in the outcome, with a likelihood ratio of χ\(^2\) (9) = 41.547, p < 0.001, for predicting the presence of NASH. Only HOMA was an independent predictor of NASH (B = 0.102, SE = 0.0373, p = 0.007). Evaluation of steatosis showed a similar trend (likelihood ratio χ\(^2\) (9) = 40.272, p < 0.001). Independent predictors of steatosis were HbA1c (B = 0.833, SE = 0.343, p = 0.015) and HOMA (B = 0.136, SE = 0.039, p < 0.001). (4) Conclusions: The above-mentioned model, including components of MUO, was significant for diagnosing NASH in patients with morbid obesity undergoing bariatric surgery. Out of the different subitems, HOMA independently predicted the presence of NASH and steatosis, while HbA1c independently predicted steatosis and fibrosis. Taken together, the parameter of glucose metabolism appears to be more accurate for the prediction of NASH than the parameters of lipid metabolism, inflammation or the presence of cardiovascular disease.
KW  - NAFLD
KW  - metabolically unhealthy obesity
KW  - obesity surgery
KW  - insulin resistance
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-319213
SN  - 2227-9059
VL  - 11
IS  - 6
ER  - 
TY  - THES
A1  - Kannapin, Felix
T1  - Untersuchungen zur Bedeutung des neurotrophen Faktors GDNF für die Interaktion zwischen enterischen Gliazellen und Enterozyten für die Regulation der Darmbarriere
T1  - Studies on the importance of the neurotrophic factor GDNF for the interaction between enteric glial cells and enterocytes for the regulation of the intestinal barrier
N2  - In der vorliegenden Dissertation wurde das Zusammenspiel von enterischen Gliazellen (EGC) und Darmepithelzellen (Caco-2) thematisiert, wobei der Fokus auf der Bedeu-tung des neurotrophen Faktors GDNF für die Interaktion zwischen den beiden genann-ten Zelltypen lag. Weiterhin wurde evaluiert, ob die Tyrosinkinase RET auch in Darme-pithelzellen für die GDNF-Signaltransduktion unter Ruhebedingungen und bei Entzün-dungen verantwortlich ist. 
Als Grundlage diente ein Ko-Kultur-Modell mit Caco-2 und EGC. Durch Permeabili-täts- und Widerstandsmessungen wurden die Auswirkungen von GDNF auf Zell-Monolayer ermittelt. Effekte auf die Barrieredifferenzierung wurden anhand subkon-fluenter Zell-Monolayer charakterisiert, wohingegen die Auswirkungen auf Entzün-dungsstimuli an konfluenten Zellen untersucht wurden. Veränderungen von Junktions-proteinen wurden mit Immunfluoreszenzfärbungen und Western-Blot-Analysen aufge-zeigt. Abschließend erfolgte eine Analyse humaner Gewebeproben von Patienten mit und ohne chronisch-entzündlichen Darmerkrankungen (CED) in Bezug auf deren GDNF-Expression.
Die verwendeten intestinalen Epithelzellen exprimieren die GDNF-Rezeptoren GFRα1, GFRα2, GFRα3 und RET. Nach Etablierung des Kultursystems zeigten Permeabilitäts-messungen, Messungen des Epithelwiderstandes sowie Immunfluoreszenz-Färbungen, dass die Differenzierung der Darmepithelzellen in der Ko-Kultur mit EGC durch GDNF vermittelt wird. Zudem war eine GDNF-abhängige, barrierestabilisierende Wirkung in einem Inflammationsmodell zu beobachten. Weiterhin wurde nachgewiesen, dass GDNF-Effekte auf Enterozyten auch im Darmepithel über die RET-Tyrosinkinase mit nachfolgender Hemmung des p38-MAPK-Signalwegs bedingt werden. Eine Stimulation der EGC mit Zytokinen bestätigte eine Hochregulation der GDNF-Expression und Sek-retion. In humanen Proben war intestinales GDNF bei schwerer Entzündung reduziert.
Zusammenfassend wurde erstmalig der Nachweis erbracht, dass von EGC sezerniertes GDNF die Differenzierung der Barriere in Darmepithelzellen induziert und diese gegen einen Zytokin-vermittelten Zusammenbruch schützt. Dies wird über eine RET-abhängige Regulation der p38-MAPK vermittelt. Die Reduktion der GDNF-Konzentration in transmuralen Gewebeproben von Patienten mit CED trägt möglicher-weise zur Pathogenese der CED bei.
N2  - The present thesis adresses the interaction of enteric glial cells (EGC) and intestinal epithelial cells (Caco-2), focusing on the importance of the neurotrophic factor GDNF for the interaction between the two cell types. Furthermore, it was evaluated whether the tyrosine kinase RET is also responsible for GDNF signal transduction in intestinal epithelial cells under resting conditions and during inflammation. A co-culture model with Caco-2 and EGC served as the base for further investigations. Permeability and resistance measurements were used to determine the effects of GDNF on cell monolayers. Effects on barrier differentiation were characterized using subconfluent cell monolayers, whereas effects on inflammatory stimuli were investigated in confluent cells. Changes in junctional proteins were revealed by immunofluorescence staining and Western blot analysis. Finally, human tissue samples from patients with and without chronic inflammatory bowel disease (IBD) were analyzed with regard to their GDNF expression. The intestinal epithelial cells used, express the GDNF receptors GFRα1, GFRα2, GFRα3 and RET. After establishment of the culture system, permeability measurements, epithelial resistance measurements and immunofluorescence staining showed that the differentiation of intestinal epithelial cells in co-culture with EGC is mediated by GDNF. Additionally, a GDNF-dependent, barrier-stabilizing effect was observed in an inflammation model. Furthermore, it was shown that GDNF effects on enterocytes are also caused in the intestinal epithelium via RET tyrosine kinase with subsequent inhibition of the p38 MAPK signaling pathway. Stimulation of EGC with cytokines confirmed an upregulation of GDNF expression and secretion. In human samples, intestinal GDNF was reduced in severe inflammation. In summary, it was demonstrated for the first time that GDNF secreted by EGC induces barrier differentiation in intestinal epithelial cells and protects them against cytokine-mediated breakdown. This is mediated via RET-dependent regulation of p38 MAPK. The reduction of GDNF levels in transmural tissue samples from patients with IBD may contribute to the pathogenesis of IBD.
KW  - Crohn-Krankheit
KW  - GDNF
KW  - Neurotrophe Faktoren
KW  - CED
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-344719
ER  - 
TY  - JOUR
A1  - Silwedel, Christine
A1  - Hütten, Matthias C.
A1  - Speer, Christian P.
A1  - Härtel, Christoph
A1  - Haarmann, Axel
A1  - Henrich, Birgit
A1  - Tijssen, Maud P. M.
A1  - Alnakhli, Abdullah Ahmed
A1  - Spiller, Owen B.
A1  - Schlegel, Nicolas
A1  - Seidenspinner, Silvia
A1  - Kramer, Boris W.
A1  - Glaser, Kirsten
T1  - Ureaplasma-driven neonatal neuroinflammation: novel insights from an ovine model
JF  - Cellular and Molecular Neurobiology
N2  - Ureaplasma species (spp.) are considered commensals of the adult genitourinary tract, but have been associated with chorioamnionitis, preterm birth, and invasive infections in neonates, including meningitis. Data on mechanisms involved in Ureaplasma-driven neuroinflammation are scarce. The present study addressed brain inflammatory responses in preterm lambs exposed to Ureaplasma parvum (UP) in utero. 7 days after intra-amniotic injection of UP (n = 10) or saline (n = 11), lambs were surgically delivered at gestational day 128–129. Expression of inflammatory markers was assessed in different brain regions using qRT-PCR and in cerebrospinal fluid (CSF) by multiplex immunoassay. CSF was analyzed for UP presence using ureB-based real-time PCR, and MRI scans documented cerebral white matter area and cortical folding. Cerebral tissue levels of atypical chemokine receptor (ACKR) 3, caspases 1-like, 2, 7, and C–X–C chemokine receptor (CXCR) 4 mRNA, as well as CSF interleukin-8 protein concentrations were significantly increased in UP-exposed lambs. UP presence in CSF was confirmed in one animal. Cortical folding and white matter area did not differ among groups. The present study confirms a role of caspases and the transmembrane receptors ACKR3 and CXCR4 in Ureaplasma-driven neuroinflammation. Enhanced caspase 1-like, 2, and 7 expression may reflect cell death. Increased ACKR3 and CXCR4 expression has been associated with inflammatory central nervous system (CNS) diseases and impaired blood–brain barrier function. According to these data and previous in vitro findings from our group, we speculate that Ureaplasma-induced caspase and receptor responses affect CNS barrier properties and thus facilitate neuroinflammation.
KW  - Ureaplasma parvum
KW  - CNS integrity
KW  - neonatal meningitis
KW  - preterm birth
KW  - immaturity
KW  - animal model
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-324285
VL  - 43
IS  - 2
ER  - 
TY  - JOUR
A1  - Gruschwitz, Philipp
A1  - Hartung, Viktor
A1  - Kleefeldt, Florian
A1  - Ergün, Süleyman
A1  - Lichthardt, Sven
A1  - Huflage, Henner
A1  - Hendel, Robin
A1  - Kunz, Andreas Steven
A1  - Pannenbecker, Pauline
A1  - Kuhl, Philipp Josef
A1  - Augustin, Anne Marie
A1  - Bley, Thorsten Alexander
A1  - Petritsch, Bernhard
A1  - Grunz, Jan-Peter
T1  - Standardized assessment of vascular reconstruction kernels in photon-counting CT angiographies of the leg using a continuous extracorporeal perfusion model
JF  - Scientific Reports
N2  - This study evaluated the influence of different vascular reconstruction kernels on the image quality of CT angiographies of the lower extremity runoff using a 1st-generation photon-counting-detector CT (PCD-CT) compared with dose-matched examinations on a 3rd-generation energy-integrating-detector CT (EID-CT). Inducing continuous extracorporeal perfusion in a human cadaveric model, we performed CT angiographies of eight upper leg arterial runoffs with radiation dose-equivalent 120 kVp acquisition protocols (CTDIvol 5 mGy). Reconstructions were executed with different vascular kernels, matching the individual modulation transfer functions between scanners. Signal-to-noise-ratios (SNR) and contrast-to-noise-ratios (CNR) were computed to assess objective image quality. Six radiologists evaluated image quality subjectively using a forced-choice pairwise comparison tool. Interrater agreement was determined by calculating Kendall’s concordance coefficient (W). The intraluminal attenuation of PCD-CT images was significantly higher than of EID-CT (414.7 ± 27.3 HU vs. 329.3 ± 24.5 HU; p < 0.001). Using comparable kernels, image noise with PCD-CT was significantly lower than with EID-CT (p ≤ 0.044). Correspondingly, SNR and CNR were approximately twofold higher for PCD-CT (p < 0.001). Increasing the spatial frequency for PCD-CT reconstructions by one level resulted in similar metrics compared to EID-CT (CNRfat; EID-CT Bv49: 21.7 ± 3.7 versus PCD-CT Bv60: 21.4 ± 3.5). Overall image quality of PCD-CTA achieved ratings superior to EID-CTA irrespective of the used reconstruction kernels (best: PCD-CT Bv60; worst: EID-CT Bv40; p < 0.001). Interrater agreement was good (W = 0.78). Concluding, PCD-CT offers superior intraluminal attenuation, SNR, and CNR compared to EID-CT in angiographies of the upper leg arterial runoff. Combined with improved subjective image quality, PCD-CT facilitates the use of sharper convolution kernels and ultimately bears the potential of improved vascular structure assessability.
KW  - experimental models of disease
KW  - preclinical research
KW  - translational research
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-357912
VL  - 13
ER  - 
TY  - JOUR
A1  - Döhler, Ida
A1  - Röder, Daniel
A1  - Schlesinger, Tobias
A1  - Nassen, Christian Alexander
A1  - Germer, Christoph-Thomas
A1  - Wiegering, Armin
A1  - Lock, Johan Friso
T1  - Risk-adjusted perioperative bridging anticoagulation reduces bleeding complications without increasing thromboembolic events in general and visceral surgery
JF  - BMC Anesthesiology
N2  - Background
Perioperative bridging of oral anticoagulation increases the risk of bleeding complications after elective general and visceral surgery. The aim of this study was to explore, whether an individual risk-adjusted bridging regimen can reduce bleeding events, while still protecting against thromboembolic events.

Methods
We performed a quality improvement study comparing bridging parameters and postoperative outcomes before (period 1) and after implementation (period 2) of a new risk-adjusted bridging regimen. The primary endpoint of the study was overall incidence of postoperative bleeding complications during 30 days postoperatively. Secondary endpoints were major postoperative bleeding, minor bleeding, thromboembolic events, postoperative red blood cell transfusion, perioperative length-of-stay (LOS) and in-hospital mortality.

Results
A total of 263 patients during period 1 and 271 patients during period 2 were compared. The included elective operations covered the entire field of general and visceral surgery. The overall incidence of bleeding complications declined from 22.1% during period 1 to 10.3% in period 2 (p < 0.001). This reduction affected both major as well as minor bleeding events (8.4% vs. 4.1%; p = 0.039; 13.7% vs. 6.3%; p = 0.004). The incidence of thromboembolic events remained low (0.8% vs. 1.1%). No changes in mortality or length-of-stay were observed.

Conclusion
It is important to balance the individual thromboembolic and bleeding risks in perioperative bridging management. The risk adjusted bridging regimen reduces bleeding events in general and visceral surgery while the risk of thromboembolism remains comparably low.
KW  - low-molecular heparin
KW  - atrial fibrillation
KW  - postoperative bleeding
KW  - thromboembolism
KW  - anticoagulation
KW  - bridging
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-357305
VL  - 23
ER  - 
TY  - JOUR
A1  - Kollmann, Catherine
A1  - Buerkert, Hannah
A1  - Meir, Michael
A1  - Richter, Konstantin
A1  - Kretzschmar, Kai
A1  - Flemming, Sven
A1  - Kelm, Matthias
A1  - Germer, Christoph-Thomas
A1  - Otto, Christoph
A1  - Burkard, Natalie
A1  - Schlegel, Nicolas
T1  - Human organoids are superior to cell culture models for intestinal barrier research
JF  - Frontiers in Cell and Developmental Biology
N2  - Loss of intestinal epithelial barrier function is a hallmark in digestive tract inflammation. The detailed mechanisms remain unclear due to the lack of suitable cell-based models in barrier research. Here we performed a detailed functional characterization of human intestinal organoid cultures under different conditions with the aim to suggest an optimized ex-vivo model to further analyse inflammation-induced intestinal epithelial barrier dysfunction. Differentiated Caco2 cells as a traditional model for intestinal epithelial barrier research displayed mature barrier functions which were reduced after challenge with cytomix (TNFα, IFN-γ, IL-1ß) to mimic inflammatory conditions. Human intestinal organoids grown in culture medium were highly proliferative, displayed high levels of LGR5 with overall low rates of intercellular adhesion and immature barrier function resembling conditions usually found in intestinal crypts. WNT-depletion resulted in the differentiation of intestinal organoids with reduced LGR5 levels and upregulation of markers representing the presence of all cell types present along the crypt-villus axis. This was paralleled by barrier maturation with junctional proteins regularly distributed at the cell borders. Application of cytomix in immature human intestinal organoid cultures resulted in reduced barrier function that was accompanied with cell fragmentation, cell death and overall loss of junctional proteins, demonstrating a high susceptibility of the organoid culture to inflammatory stimuli. In differentiated organoid cultures, cytomix induced a hierarchical sequence of changes beginning with loss of cell adhesion, redistribution of junctional proteins from the cell border, protein degradation which was accompanied by loss of epithelial barrier function. Cell viability was observed to decrease with time but was preserved when initial barrier changes were evident. In summary, differentiated intestinal organoid cultures represent an optimized human ex-vivo model which allows a comprehensive reflection to the situation observed in patients with intestinal inflammation. Our data suggest a hierarchical sequence of inflammation-induced intestinal barrier dysfunction starting with loss of intercellular adhesion, followed by redistribution and loss of junctional proteins resulting in reduced barrier function with consecutive epithelial death.
KW  - intestinal epithelial barrier
KW  - Caco2 cells
KW  - intestinal organoids
KW  - enteroids
KW  - gut barrier
KW  - inflammatory cell model
KW  - inflammation
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-357317
SN  - 2296-634X
VL  - 11
ER  - 
TY  - JOUR
A1  - Gruschwitz, Philipp
A1  - Hartung, Viktor
A1  - Kleefeldt, Florian
A1  - Peter, Dominik
A1  - Lichthardt, Sven
A1  - Huflage, Henner
A1  - Grunz, Jan-Peter
A1  - Augustin, Anne Marie
A1  - Ergün, Süleyman
A1  - Bley, Thorsten Alexander
A1  - Petritsch, Bernhard
T1  - Continuous extracorporeal femoral perfusion model for intravascular ultrasound, computed tomography and digital subtraction angiography
JF  - PLoS One
N2  - Objectives
We developed a novel human cadaveric perfusion model with continuous extracorporeal femoral perfusion suitable for performing intra-individual comparison studies, training of interventional procedures and preclinical testing of endovascular devices. Objective of this study was to introduce the techniques and evaluate the feasibility for realistic computed tomography angiography (CTA), digital subtraction angiography (DSA) including vascular interventions, and intravascular ultrasound (IVUS).

Methods
The establishment of the extracorporeal perfusion was attempted using one formalin-fixed and five fresh-frozen human cadavers. In all specimens, the common femoral and popliteal arteries were prepared, introducer sheaths inserted, and perfusion established by a peristaltic pump. Subsequently, we performed CTA and bilateral DSA in five cadavers and IVUS on both legs of four donors. Examination time without unintentional interruption was measured both with and without non-contrast planning CT. Percutaneous transluminal angioplasty and stenting was performed by two interventional radiologists on nine extremities (five donors) using a broad spectrum of different intravascular devices.

Results
The perfusion of the upper leg arteries was successfully established in all fresh-frozen but not in the formalin-fixed cadaver. The experimental setup generated a stable circulation in each procedure (ten upper legs) for a period of more than six hours. Images acquired with CT, DSA and IVUS offered a realistic impression and enabled the sufficient visualization of all examined vessel segments. Arterial cannulating, percutaneous transluminal angioplasty as well as stent deployment were feasible in a way that is comparable to a vascular intervention in vivo. The perfusion model allowed for introduction and testing of previously not used devices.

Conclusions
The continuous femoral perfusion model can be established with moderate effort, works stable, and is utilizable for medical imaging of the peripheral arterial system using CTA, DSA and IVUS. Therefore, it appears suitable for research studies, developing skills in interventional procedures and testing of new or unfamiliar vascular devices.
KW  - continuous extracorporeal femoral perfusion model
KW  - novel human cadaveric perfusion model
KW  - computed tomography angiography (CTA)
KW  - digital subtraction angiography (DSA)
KW  - intravascular ultrasound (IVUS)
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-350136
SN  - 1932-6203
VL  - 18
IS  - 5
ER  - 
TY  - JOUR
A1  - Madrahimov, Nodir
A1  - Mutsenko, Vitalii
A1  - Natanov, Ruslan
A1  - Radaković, Dejan
A1  - Klapproth, André
A1  - Hassan, Mohamed
A1  - Rosenfeldt, Mathias
A1  - Kleefeldt, Florian
A1  - Aleksic, Ivan
A1  - Ergün, Süleyman
A1  - Otto, Christoph
A1  - Leyh, Rainer G.
A1  - Bening, Constanze
T1  - Multiorgan recovery in a cadaver body using mild hypothermic ECMO treatment in a murine model
JF  - Intensive Care Medicine Experimental
N2  - Background
Transplant candidates on the waiting list are increasingly challenged by the lack of organs. Most of the organs can only be kept viable within very limited timeframes (e.g., mere 4–6 h for heart and lungs exposed to refrigeration temperatures ex vivo). Donation after circulatory death (DCD) using extracorporeal membrane oxygenation (ECMO) can significantly enlarge the donor pool, organ yield per donor, and shelf life. Nevertheless, clinical attempts to recover organs for transplantation after uncontrolled DCD are extremely complex and hardly reproducible. Therefore, as a preliminary strategy to fulfill this task, experimental protocols using feasible animal models are highly warranted. The primary aim of the study was to develop a model of ECMO-based cadaver organ recovery in mice. Our model mimics uncontrolled organ donation after an “out-of-hospital” sudden unexpected death with subsequent “in-hospital” cadaver management post-mortem. The secondary aim was to assess blood gas parameters, cardiac activity as well as overall organ state. The study protocol included post-mortem heparin–streptokinase administration 10 min after confirmed death induced by cervical dislocation under full anesthesia. After cannulation, veno-arterial ECMO (V–A ECMO) was started 1 h after death and continued for 2 h under mild hypothermic conditions followed by organ harvest. Pressure- and flow-controlled oxygenated blood-based reperfusion of a cadaver body was accompanied by blood gas analysis (BGA), electrocardiography, and histological evaluation of ischemia–reperfusion injury. For the first time, we designed and implemented, a not yet reported, miniaturized murine hemodialysis circuit for the treatment of severe hyperkalemia and metabolic acidosis post-mortem.

Results
BGA parameters confirmed profound ischemia typical for cadavers and incompatible with normal physiology, including extremely low blood pH, profound negative base excess, and enormously high levels of lactate. Two hours after ECMO implantation, blood pH values of a cadaver body restored from < 6.5 to 7.3 ± 0.05, pCO2 was lowered from > 130 to 41.7 ± 10.5 mmHg, sO2, base excess, and HCO3 were all elevated from below detection thresholds to 99.5 ± 0.6%, − 4 ± 6.2 and 22.0 ± 6.0 mmol/L, respectively (Student T test, p < 0.05). A substantial decrease in hyperlactatemia (from > 20 to 10.5 ± 1.7 mmol/L) and hyperkalemia (from > 9 to 6.9 ± 1.0 mmol/L) was observed when hemodialysis was implemented. On balance, the first signs of regained heart activity appeared on average 10 min after ECMO initiation without cardioplegia or any inotropic and vasopressor support. This was followed by restoration of myocardial contractility with a heart rate of up to 200 beats per minute (bpm) as detected by an electrocardiogram (ECG). Histological examinations revealed no evidence of heart injury 3 h post-mortem, whereas shock-specific morphological changes relevant to acute death and consequent cardiac/circulatory arrest were observed in the lungs, liver, and kidney of both control and ECMO-treated cadaver mice.

Conclusions
Thus, our model represents a promising approach to facilitate studying perspectives of cadaveric multiorgan recovery for transplantation. Moreover, it opens new possibilities for cadaver organ treatment to extend and potentiate donation and, hence, contribute to solving the organ shortage dilemma.
KW  - extracorporeal membrane oxygenation
KW  - cadaver multiorgan preservation
KW  - mild hypothermia
KW  - post-mortem heart recovery
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-357381
VL  - 11
ER  - 
TY  - JOUR
A1  - Gruschwitz, Philipp
A1  - Hartung, Viktor
A1  - Ergün, Süleyman
A1  - Peter, Dominik
A1  - Lichthardt, Sven
A1  - Huflage, Henner
A1  - Hendel, Robin
A1  - Pannenbecker, Pauline
A1  - Augustin, Anne Marie
A1  - Kunz, Andreas Steven
A1  - Feldle, Philipp
A1  - Bley, Thorsten Alexander
A1  - Grunz, Jan-Peter
T1  - Comparison of ultrahigh and standard resolution photon-counting CT angiography of the femoral arteries in a continuously perfused in vitro model
JF  - European Radiology Experimental
N2  - Background
With the emergence of photon-counting CT, ultrahigh-resolution (UHR) imaging can be performed without dose penalty. This study aims to directly compare the image quality of UHR and standard resolution (SR) scan mode in femoral artery angiographies.

Methods
After establishing continuous extracorporeal perfusion in four fresh-frozen cadaveric specimens, photon-counting CT angiographies were performed with a radiation dose of 5 mGy and tube voltage of 120 kV in both SR and UHR mode. Images were reconstructed with dedicated convolution kernels (soft: Body-vascular (Bv)48; sharp: Bv60; ultrasharp: Bv76). Six radiologists evaluated the image quality by means of a pairwise forced-choice comparison tool. Kendall’s concordance coefficient (W) was calculated to quantify interrater agreement. Image quality was further assessed by measuring intraluminal attenuation and image noise as well as by calculating signal-to-noise ratio (SNR) and contrast-to-noise ratios (CNR).

Results
UHR yielded lower noise than SR for identical reconstructions with kernels ≥ Bv60 (p < 0.001). UHR scans exhibited lower intraluminal attenuation compared to SR (Bv60: 406.4 ± 25.1 versus 418.1 ± 30.1 HU; p < 0.001). Irrespective of scan mode, SNR and CNR decreased while noise increased with sharper kernels but UHR scans were objectively superior to SR nonetheless (Bv60: SNR 25.9 ± 6.4 versus 20.9 ± 5.3; CNR 22.7 ± 5.8 versus 18.4 ± 4.8; p < 0.001). Notably, UHR scans were preferred in subjective assessment when images were reconstructed with the ultrasharp Bv76 kernel, whereas SR was rated superior for Bv60. Interrater agreement was high (W = 0.935).

Conclusions
Combinations of UHR scan mode and ultrasharp convolution kernel are able to exploit the full image quality potential in photon-counting CT angiography of the femoral arteries.

Relevance statement
The UHR scan mode offers improved image quality and may increase diagnostic accuracy in CT angiography of the peripheral arterial runoff when optimized reconstruction parameters are chosen.

Key points
• UHR photon-counting CT improves image quality in combination with ultrasharp convolution kernels.

• UHR datasets display lower image noise compared with identically reconstructed standard resolution scans.

• Scans in UHR mode show decreased intraluminal attenuation compared with standard resolution imaging.
KW  - CT angiography
KW  - femoral arteries
KW  - photon-counting computed tomography (CT)
KW  - small pixel effect
KW  - ultrahigh resolution
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-357905
VL  - 7
ER  - 
TY  - JOUR
A1  - Zaitseva, Olena
A1  - Hoffmann, Annett
A1  - Löst, Margaretha
A1  - Anany, Mohamed A.
A1  - Zhang, Tengyu
A1  - Kucka, Kirstin
A1  - Wiegering, Armin
A1  - Otto, Christoph
A1  - Wajant, Harald
T1  - Antibody-based soluble and membrane-bound TWEAK mimicking agonists with FcγR-independent activity
JF  - Frontiers in Immunology
N2  - Fibroblast growth factor (FGF)-inducible 14 (Fn14) activates the classical and alternative NFκB (nuclear factor ‘kappa-light-chain-enhancer’ of activated B-cells) signaling pathway but also enhances tumor necrosis factor (TNF)-induced cell death. Fn14 expression is upregulated in non-hematopoietic cells during tissue injury and is also often highly expressed in solid cancers. In view of the latter, there were and are considerable preclinical efforts to target Fn14 for tumor therapy, either by exploiting Fn14 as a target for antibodies with cytotoxic activity (e.g. antibody-dependent cellular cytotoxicity (ADCC)-inducing IgG variants, antibody drug conjugates) or by blocking antibodies with the aim to interfere with protumoral Fn14 activities. Noteworthy, there are yet no attempts to target Fn14 with agonistic Fc effector function silenced antibodies to unleash the proinflammatory and cell death-enhancing activities of this receptor for tumor therapy. This is certainly not at least due to the fact that anti-Fn14 antibodies only act as effective agonists when they are presented bound to Fcγ receptors (FcγR). Thus, there are so far no antibodies that robustly and selectively engage Fn14 signaling without triggering unwanted FcγR-mediated activities. In this study, we investigated a panel of variants of the anti-Fn14 antibody 18D1 of different valencies and domain architectures with respect to their inherent FcγR-independent ability to trigger Fn14-associated signaling pathways. In contrast to conventional 18D1, the majority of 18D1 antibody variants with four or more Fn14 binding sites displayed a strong ability to trigger the alternative NFκB pathway and to enhance TNF-induced cell death and therefore resemble in their activity soluble (TNF)-like weak inducer of apoptosis (TWEAK), one form of the natural occurring ligand of Fn14. Noteworthy, activation of the classical NFκB pathway, which naturally is predominately triggered by membrane-bound TWEAK but not soluble TWEAK, was preferentially observed with a subset of constructs containing Fn14 binding sites at opposing sites of the IgG scaffold, e.g. IgG1-scFv fusion proteins. A superior ability of IgG1-scFv fusion proteins to trigger classical NFκB signaling was also observed with the anti-Fn14 antibody PDL192 suggesting that we identified generic structures for Fn14 antibody variants mimicking soluble and membrane-bound TWEAK.
KW  - agonistic antibodies
KW  - cell death
KW  - FcγR
KW  - Fn14
KW  - NFκB
KW  - TNF receptor superfamily
KW  - TWEAK
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-323116
VL  - 14
ER  -