Effects of GABA receptor antagonization on oligodendroglial development and myelination of the neonatal rat cortex

Die (intensiv)medizinischen Behandlungsmöglichkeiten von Früh- und Neugeborenen haben sich in den letzten Dekaden drastisch verbessert. Kommt ein Säugling frühzeitig auf die Welt, ist jedoch seine Gehirnentwicklung nicht vollends abgeschlossen und zudem postnatal externen Einflüssen ausgesetzt. Spezifisch gehen damit Myelinisierungsdefizite, Schädigungen von γ-Aminobuttersäure-(GABAergen) Interneuronen und Veränderungen in der oligodendrogliären Entwicklung einher. Inwieweit diese Prozesse sich gegenseitig bedingen, bleibt weitestgehend ungeklärt. Vorherige Daten zeigten auf, dass Myelin-bildende oligodendrogliäre Zellen GABA-Rezeptoren exprimieren. Ein Einfluss von GABA über diese Rezeptoren auf Oligodendroglia und die Myelinisierung scheint somit denkbar. Ziel der vorliegenden Arbeit war es daher, die Myelinproduktion und die GABA-induzierte Reifung, Proliferation und Apoptose von Oligodendroglia im Gehirn der neonatalen Ratte nach pharmakologischer Blockade der GABAA und GABAB-Rezeptoren zu untersuchen. Vom postnatalen Tag (P) 6 bis P11 wurde der reverse GABAA-Rezeptor-Agonist DMCM oder der GABAB-Rezeptor-Antagonist CGP täglich intraperitoneal injiziert. Die Analysen folgten zu P11 und P15. Western Blots und Immunhistochemie dienten zur Messung der MBP Expression. Weiterhin bestimmten wir mittels immunhistochemischer Färbung zur Evaluation der oligodendrogliären Reifung die Rate der CC1+OLIG2+ und CNP+OLIG2+ Zellen sowie zur Auswertung der Proliferation die Rate der PCNA+OLIG2+ Oligodendroglia. Oligodendrogliäre Vorläuferzellen wurden mit PDGFRα-Antikörpern gefärbt. Ebenso wurde eine Analyse der oligodendrogliären Apoptose (CASP3+OLIG2+) und aller apoptotischen Zellen (CASP3+DAPI+) vorgenommen. Zusätzlich erfolgte die Bestimmung der Pdgfrα Genexpression mittels qPCR und der CNP Proteinexpression via Western Blot. Die MBP-Expression wies eine signifikante Reduktion, insbesondere nach CGP-Behandlung, zum Zeitpunkt P15 auf. Ebenso ergab sich in jener Tiergruppe eine temporäre Absenkung von reifen CNP+ Oligodendrozyten sowie der CNP Proteinexpression im Alter P11. Zu P15 war ein Anstieg der Proliferation von Oligodendroglia (PCNA+OLIG2+), und spezifisch der oligodendrogliären Vorläuferzellen (PDGFRα+OLIG2+), nach GABAB-Rezeptor-Antagonisierung erkennbar. Die Pdgfrα Genexpressionen zeigte sich nach Behandlung unverändert. Gleiches gilt für den apoptotischen Zelltod sowie für Proliferations- und Reifungsuntersuchungen nach GABAA-Rezeptor-Blockade. Unsere in vivo Studie an neugeborenen Ratten deutet darauf hin, dass besonders die GABAB-Rezeptor-Aktivität eine modulierende Funktion in der Oligodendroglia-Entwicklung sowie in der adäquaten Myelinisierung innehält. Daraus schlussfolgernd, spielen GABAB-Rezeptoren eine zentrale Rolle im Verständnis von auf Myelindefiziten basierenden Pathologien und könnten künftig einen vielversprechenden Ansatzpunkt in der Regulierung der Gehirnentwicklung Frühgeborener über die Myelinbildung bieten.Through (intensive) medical care, treatment possibilities of premature and newborn children have improved drastically during the last decades. However, when a child is born preterm, its brain development is not fully completed yet and is furthermore exposed to postnatal external influences. The specific consequences range from myelination deficits up to impairments of γ-aminobutyric acid-(GABAergic) interneurons and changes in oligodendroglial development. To what extent these processes are mutually dependent, is largely unknown. Prior data has shown that myelin forming oligodendroglial cells express GABA receptors. An impact of GABA via these receptors on oligodendroglia and myelination appears conceivable. In this study, we aimed to examine the myelin production as well as the GABA-induced maturation, proliferation, and apoptosis of oligodendroglia in the brain of neonatal rats after pharmacologically blocking GABAA and GABAB receptors. From postnatal day 6 (P6) to P11, the reverse GABAA receptor agonist (DMCM) or the GABAB receptor antagonist CGP were injected intraperitoneally on a daily basis. This was followed by analysis at P11 and P15. Western blots and immunohistochemistry were performed to determine the expression of MBP. Furthermore, via immunohistochemical stainings, we assessed the rates of CC1+OLIG2+ and CNP+OLIG2+ cells to evaluate maturation and analyzed the rate of PCNA+OLIG2+ oligodendrocytes for proliferation. Oligodendrocyte precursor cells were stained with antibodies to PDGFRα+. An analysis of the oligodendroglial apoptosis (CASP3+OLIG2+) and of apoptotic cells in total (CASP3+DAPI+) was performed. Additionally, we assessed the Pdgfrα gene expression through qPCR and the protein expression of CNP via Western blot. MBP expression showed a significant reduction, especially after treatment with CGP, at P15. Also, the number of mature CNP+ oligodendrocytes and the CNP protein expression and decreased temporarily at P11 in the same animal group. At P15, the proliferation of oligodendroglia (PCNA+OLIG2+), and especially of oligodendrocyte precursor cells (PDGFRα+OLIG2+), increased after antagonization of GABAB receptors. Pdgfrα gene expression remained unaffected after treatment. The same accounts for apoptotic cell death and all examinations of proliferation and maturation after GABAA receptor blockade. Our in vivo study in neonatal rats indicates that especially GABAB receptor activity fulfills a modulating role concerning oligodendroglial development and adequate myelination. As a conclusion, GABAB receptors play a key role in the understanding of pathologies caused by myelin deficits and could offer a promising approach in the regulation of the brain development among preterm children via their myelin synthesis

Work-life balance in physicians working in two emergency departments of a university hospital: Results of a qualitative focus group study

By applying an explorative approach, we aimed to identify a wide set of challenges and opportunities for the compatibility of the work and life domains in emergency department (ED) physicians as well as their suggestions for practical approaches to improve work-life balance. Four focus groups with 14 physicians of differing hierarchical position and family status were carried out at two EDs of one major university hospital. Data analysis was based on qualitative content analysis. Discussed themes within main categories included ED work conditions, aspects of residency training, physician's mentality and behaviors as well as context factors of university medicine. Working in an ED is associated with a comparatively high work-life-interference, mostly due to the unpredictable nature of ED work. Based on our context-specific findings, further research might address factors influencing work-life balance in ED physicians with a mixed-methods approach for identification of relevant associations and intervention approaches in this field

Postnatal myelination of the immature rat cingulum is regulated by GABAB receptor activity

Myelination of axons in the neonatal brain is a highly complex process primarily achieved by oligodendroglial cells (OLs). OLs express receptors for gamma-aminobutyric acid (GABA) which is released from cortical interneurons on a basal level, while glial cells can be a source of GABA, too. We investigated GABA-induced oligodendroglial maturation, proliferation, apoptosis, and myelin production after pharmacological inhibition of GABA(A) and GABA(B) in the neonatal rat brain. Daily injections of the reverse GABA(A) receptor agonist (DMCM) and the GABA(B) receptor antagonist (CGP35348) were performed from postnatal day 6 (P6) to P11. MBP expression was examined by Western blots and immunohistochemistry. Furthermore, we determined the number of CC1(+)OLIG2(+) and CNP(+)OLIG2(+) cells to assess maturation, the number of PCNA(+)OLIG2(+) oligodendrocytes to assess proliferation, the number of oligodendrocyte precursor cells (PDGFR alpha(+)OLIG2(+)), and apoptosis of OLs (CASP3A(+)OLIG2(+)) as well as apoptotic cells in total (CASP3A(+)DAPI(+)) at P11 and P15. In addition, we analyzed the expression Pdgfr alpha and CNP. MBP expression was significantly reduced after CGP treatment at P15. In the same animal group, CNP expression and CNP(+)OLIG2(+) cells decreased temporarily at P11. At P15, the proliferation of PCNA(+)OLIG2(+) cells and the number of PDGFR alpha(+)OLIG2(+) cells increased after GABA(B) receptor antagonization whereas no significant differences were visible in the Pdgfr alpha gene expression. No changes in apoptotic cell death were observed. CGP treatment induced a transient maturational delay at P11 and deficits in myelin expression at P15 with increased oligodendroglial proliferation. Our in vivo study indicates GABA(B) receptor activity as a potential modulator of oligodendroglial development

The syncope core management process in the emergency department:a consensus statement of the EUSEM syncope group

The European Society of Cardiology issued updated syncope guidelines in 2018 which included recommendations for managing syncope in the emergency department (ED) setting. However, these guidelines lack detailed process-oriented instructions regarding the fact that ED syncope patients initially present with a transient loss of consciousness (TLOC), which can have a broad spectrum of causes. This study aims to establish a European consensus on the general process of the workup and care for patients with suspected syncope and provides rules for sufficient and systematic management of the broad group of syncope (initially presenting as TLOC) patients in the ED. A variety of European diagnostic and therapeutic standards for syncope patients were reviewed and summarized in three rounds of a modified Delphi process by the European Society for Emergency Medicine syncope group. Based on a consensus statement, a detailed process pathway is created. The primary outcome of this work is the presentation of a universal process pathway for the structured management of syncope patients in European EDs. The here presented extended event process chain (eEPC) summarizes and homogenizes the process management of European ED syncope patients. Additionally, an exemplary translation of the eEPC into a practice-based flowchart algorithm, which can be used as an example for practical use in the ED, is provided in this work. Syncope patients, initially presenting with TLOC, are common and pose challenges in the ED. Despite variations in process management across Europe, the development of a universally applicable syncope eEPC in the ED was successfully achieved. Key features of the consensus and eEPC include ruling out life-threatening causes, distinguishing syncope from nonsyncopal TLOCs, employing syncope risk stratification categories and based on this, making informed decisions regarding admission or discharge.</p

Universitäre Notaufnahmen in der Coronapandemie – Ergebnisse des ReCovERRegisters / University emergency departments in the corona pandemic—Results from the ReCovER registry

Background: The current COVID-19 pandemic, despite the availability of rapid tests and the start of the vaccination campaign, continues to pose major challenges to emergency departments (ED). Structured collection of demographic, clinical, as well as treatment-related data provides the basis for establishing evidence-based processes and treatment concepts. Aim of the work: To present the systematic collection of clinical parameters in patients with suspected COVID-19 in the Registry for COVID-19 in the Emergency Room (ReCovER) and descriptive presentation of the first 1000 patients. Materials and methods: Data from patients with suspected COVID-19, regardless of evidence of SARS-CoV‑2 infection, are continuously entered into a web-based, anonymized registry in ED at six university hospitals. Results: Between 19 May 2020 and 13 January 2021, 1000 patients were entered into the registry, of whom 594 patients (59.4%) were in the SARS-CoV‑2 positive group (PG) and 406 patients (40.6%) were in the negative group (NG). Patients of the PG had significantly fewer pre-existing conditions and a significantly longer latency between symptom onset and presentation to the ED (median 5 vs. 3 days), were more likely to suffer from cough, myalgia, fatigue, and loss of smell/taste and had significantly higher oxygen requirements than NG patients. The rate of severe disease progression was significantly higher in the PG, and persistent symptoms were more common after discharge (11.1 vs. 4.6%). Conclusions: The multicenter collection of comprehensive clinical data on COVID-19 suspected cases in the ED allows analysis of aspects specific to the situation in Germany in particular. This is essential for a targeted review and adaptation of internationally published strategies

University emergency departments in the corona pandemic-Results from the ReCovER registry

Background The current COVID-19 pandemic, despite the availability of rapid tests and the start of the vaccination campaign, continues to pose major challenges to emergency departments (ED). Structured collection of demographic, clinical, as well as treatment-related data provides the basis for establishing evidence-based processes and treatment concepts. Aim of the work To present the systematic collection of clinical parameters in patients with suspected COVID-19 in the Registry for COVID-19 in the Emergency Room (ReCovER) and descriptive presentation of the first 1000 patients. Materials and methods Data from patients with suspected COVID-19, regardless of evidence of SARS-CoV-2 infection, are continuously entered into a web-based, anonymized registry in ED at six university hospitals. Results Between 19 May 2020 and 13 January 2021, 1000 patients were entered into the registry, of whom 594 patients (59.4%) were in the SARS-CoV-2 positive group (PG) and 406 patients (40.6%) were in the negative group (NG). Patients of the PG had significantly fewer pre-existing conditions and a significantly longer latency between symptom onset and presentation to the ED (median 5 vs. 3 days), were more likely to suffer from cough, myalgia, fatigue, and loss of smell/taste and had significantly higher oxygen requirements than NG patients. The rate of severe disease progression was significantly higher in the PG, and persistent symptoms were more common after discharge (11.1 vs. 4.6%). Conclusions The multicenter collection of comprehensive clinical data on COVID-19 suspected cases in the ED allows analysis of aspects specific to the situation in Germany in particular. This is essential for a targeted review and adaptation of internationally published strategies