Morphological and functional characterisation of a new murine serum-free in vitro model of the blood-brain barrier

Die Blut-Hirn Schranke stellt eine Barriere dar, die den Durchtritt von Substanzen aus dem Blut in das Gehirn kontrolliert. In vitro-Modelle der Blut-Hirn Schranke können dabei helfen, die regulatorischen Vorgänge an dieser Barriere zu verstehen und gegebenenfalls die Behand-lung von Erkrankungen wie dem Kreuzfeld-Jakob-Syndrom, Alzheimer oder Multiple Sclerose zu verbessern. In der vorliegenden Arbeit wird ein serum-freies in vitro-Modell vorgestellt, dass auf murinen Endothelzellen aus den cerebralen Kapillaren basiert. Es konnte gezeigt werden, dass Hydrocortison in physiologischen Konzentrationen die Barriereeigen-schaften dDer Zellen verstärkt und so zu der Integrität der Barriere unter den serumfreien Bedingungen beiträgt. Es lassen sich dabei Veränderungen am Aktinzytoskelett festellen, die mit Änderungen der mechanischen Eigenschaften und des transendothelialen elektrischen Widerstandes (TEER) der Zellen einhergehen. Hydrocortison verstärkt den TEER, wobei sowohl eine Veränderung im Zell-Substrat-Kontakt sowie im Zell-Zellkontakt detektiert werden kann

A β-Lactam Antibiotic Dampens Excitotoxic Inflammatory CNS Damage in a Mouse Model of Multiple Sclerosis

In multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE), impairment of glial “Excitatory Amino Acid Transporters” (EAATs) together with an excess glutamate-release by invading immune cells causes excitotoxic damage of the central nervous system (CNS). In order to identify pathways to dampen excitotoxic inflammatory CNS damage, we assessed the effects of a β-lactam antibiotic, ceftriaxone, reported to enhance expression of glial EAAT2, in “Myelin Oligodendrocyte Glycoprotein” (MOG)-induced EAE. Ceftriaxone profoundly ameliorated the clinical course of murine MOG-induced EAE both under preventive and therapeutic regimens. However, ceftriaxone had impact neither on EAAT2 protein expression levels in several brain areas, nor on the radioactive glutamate uptake capacity in a mixed primary glial cell-culture and the glutamate-induced uptake currents in a mammalian cell line mediated by EAAT2. Moreover, the clinical effect of ceftriaxone was preserved in the presence of the EAAT2-specific transport inhibitor, dihydrokainate, while dihydrokainate alone caused an aggravated EAE course. This demonstrates the need for sufficient glial glutamate uptake upon an excitotoxic autoimmune inflammatory challenge of the CNS and a molecular target of ceftriaxone other than the glutamate transporter. Ceftriaxone treatment indirectly hampered T cell proliferation and proinflammatory INFγ and IL17 secretion through modulation of myelin-antigen presentation by antigen-presenting cells (APCs) e.g. dendritic cells (DCs) and reduced T cell migration into the CNS in vivo. Taken together, we demonstrate, that a β-lactam antibiotic attenuates disease course and severity in a model of autoimmune CNS inflammation. The mechanisms are reduction of T cell activation by modulation of cellular antigen-presentation and impairment of antigen-specific T cell migration into the CNS rather than or modulation of central glutamate homeostasis

Rock and palaeomagnetic evidence for the Plio-Pleistocene palaeoclimatic change recorded in Upper Rhine Graben sediments (Core Ludwigshafen-Parkinsel)

In the area of Ludwigshafen (Germany; Upper Rhine Graben (URG); Fig. 1) we sampled a core (P34) which was recovered during the exploration for groundwater resources. The core comprises 300 m of Quaternary and Tertiary sediments (Fig. 2). Rockmagnetic parameters measured are: NRM (natural remanent magnetization); characteristic remanent magnetization (ChRM, could be isolated using demagnetization experiments (alternating field and thermal) Fig. 3); magnetic susceptibility measured on core and discrete samples compared with interpretation of polarity (Fig. 5); as demonstrated in figure 6, a clear correlation of heavy mineral data (Hagedorn & Boenigk, 2008; doi:10.1016/j.quascirev.2005.01.018) and susceptibility data is apparent; the so-called S-ratio (Fig. 7a) gives us information about the relative amounts of high-coercivity ('hard') to low-coercivity ('soft') remanence and therefore a fair estimate of the importance of antiferromagnetics (goethite, hematite) versus ferrimagnetics (soft magnetite, iron-sulphides); "saturation"IRM curves (Fig. 7b, c) also show a clear subdivision in soft (above 177 m) and hard (below 177 m) remanence carriers; thermal demagnetization of "S"IRM identifies greigite or (Ti) -magnetite (Fig. 8a) for the upper (alpine influenced) part of the drill whereas the lower Pliocene part is dominated by greigite (Fig. 8b); alternating field (AF) demagnetization of samples from the upper part often show acquisition of significant gyroremanent magnetization (Fig. 10a), a typical property of greigite (Snowball, 1997; doi:10.1111/j.1365-246X.1997.tb04498.x); we used a technique after Van Velzen and Zijderfeld (1992; doi:10.1111/j.1365-246X.1992.tb00715.x) detecting greigite instead of pyrrhotite (Fig. 10b); Combination of different parameters in biplots can help to separate various magnetic components (Fig. 11 a+b). We applied this method by combining anhysteretic remanent magnetization (ARM) and IRM measurements in different ways. ARM against IRM (Fig. 11a) demonstrates high concentration differences for samples from the upper part (above 177 m) of the profile and narrow plotting (low concentration variations) for samples of the lower part (below 177 m); A similar plot, the relation of ARM normalized by IRM and ARM, emphasizes this result (Fig. 11b). Again, two different clusters (high coercivity mineral (goethite) in the lower and low coercivity mineral (greigite) in the upper part of the profile) are obvious (with the exception of some samples in a mixed zone)

Preface: The Heidelberg Basin Drilling Project

Seit dem späten Pliozän / frühen Pleistozän stellt der Rhein als einer der größten europäischen Flüsse das einzige Entwässerungssystem dar, welches die Alpen mit der Nordsee verbindet. Auf seinem Verlauf von den Alpen bis hin zum Ärmelkanal passiert er unterschiedliche geomorphologische und geologische Einheiten, von denen der Oberrheingraben die Hauptsedimentfalle bildet. Während die alpinen Vorlandbecken aufgrund der hohen Dynamik des Gesamtsystems nur ein geringes Erhaltungspotenzial hinsichtlich der Sedimentablagerung aufweisen, und das Ablagerungsgebiet unmittelbar an der Nordseeküste mehrfach signifikant durch pleistozäne Meeresspiegelschwankungen beeinflusst wurde, bietet die andauernde Subsidenz des Oberrheingrabens einmalige Bedingungen für die kontinuierliche Akkumulation von Sedimenten.researc

Puromycin-purified rat brain microvascular endothelial cell cultures exhibit improved barrier properties in response to glucocorticoid induction

In vitro blood-brain barrier (BBB) models using primary rat brain microvessel endothelial cells (BMEC) are often hampered by a lack of culture purity and poor barrier properties. To address these problems, the translation inhibitor puromycin was used to purify rat BMEC cultures. BMEC purities of 99.8% were routinely attained using puromycin treatment, and this technique proved to be far superior to other purification methods of similar difficulty. In contrast to cultures without puromycin treatment, purity of puromycin-treated cultures was unaffected by initial seeding density. Next, rat BMEC monolayer transendothelial electrical resistance (TEER) was increased by glucocorticoid treatment with either corticosterone (CORT) or hydrocortisone (HC), and a corresponding decrease in monolayer permeability to small molecules was observed. Importantly, cultures treated with both puromycin and glucocorticoid attained significantly higher TEER values (CORT 168 +/- 13 Omega x cm2; HC 218 +/- 66 Omega x cm2) than those treated by the glucocorticoid alone (CORT 57 +/- 5 Omega x cm2; HC 70 +/- 2 Omega x cm2). Glucocorticoid induction resulted in BMEC morphological changes that accompanied the increases in TEER, and BMEC tight junctions exhibited improved integrity as visualized by the localization of tight junction proteins zonula occluden-1, occludin and claudin-5. The combined use of puromycin and glucocorticoid therefore provides an in vitro system that is well suited for molecular level BBB investigations