Einfluss von Indomethazin auf die adulte hippocampale Neurogenese und viskoelastische Eigenschaften des Gehirns im MPTP-Mausmodell für Dopamindepletion

Die Neurogenese im Gyrus dentatus (DG) des Hippocampus kann durch diverse Faktoren wie eine modulierte Transmitterhomöostase oder Entzündung beeinflusst werden und ist auch in neurodegenerativen Erkrankungen verändert. Mediatoren einer Entzündung sind zum Beispiel Zytokine oder Prostaglandine, wobei letztere durch das Enzym Cyclooxygenase (COX) erzeugt werden. Ob eine COX-Hemmung und dadurch modulierte Entzündungsreaktionen die adulte Neurogenese im DG in neurodegenerativen Erkrankungen beeinflussen, ist bisher unklar. Eine veränderte Neurogenese oder ein neuronaler Zellverlust in neurodegenerativen Erkrankungen könnte außerdem zu einer modifizierten Zusammensetzung des zellulären Netzwerks führen und sich in den viskoelastischen Eigenschaften widerspiegeln, welche durch die Messparameter des neuen bildgebenden Verfahrens Magnetresonanz-Elastographie (MRE) ermittelt werden könnten. Veränderte viskoelastische Parameter des Gehirns wurden bereits in Patienten mit neurodegenerativen Erkrankungen beobachtet, aber bisher gibt es nur wenige Studien zur Untersuchung der zugrundeliegenden zellulären Mechanismen. In der vorliegenden Arbeit wurden die Veränderungen viskoelastischer Eigenschaften mittels MRE und mögliche basierende zelluläre Mechanismen im Hippocampus (Studie 1) und in der SN (Studie 2) im 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridin (MPTP)-Mausmodell für Neurodegeneration mit resultierender Dopamindepletion untersucht. Des Weiteren wurde der Einfluss des nichtselektiven COX-Hemmers Indomethazin auf die adulte hippocampale Neurogenese und deren regulatorische Signalwege sowie die Entzündungsreaktionen im DG und SN eruiert (Studie 3). Die hippocampale Neurogenese und zelluläre Entzündungsreaktion wurden unter Zuhilfenahme immunhistochemischer Färbungen beurteilt. Ferner wurden Veränderungen neurogeneserelevanter Signalwege mit Hilfe der quantitativen Polymerase-Kettenreaktion und in Zytokinkonzentrationen mittels enzymatischen Immunadsorptionsverfahrens bestimmt. Nach MPTP-Behandlung zeigte sich im Hippocampus eine transient höhere Anzahl neuer Vorläuferzellen, welche in einem kurzfristig gesteigerten prozentualen Anteil neuer Neurone resultierte und somit zu einer transient höheren Viskoelastizität führte. In der SN hatte der Verlust dopaminerger Neurone eine Verringerung viskoelastischer Eigenschaften zur Folge. Die Anzahl neuer reifer Neurone im DG war zu einem späteren Zeitpunkt nach MPTP-Gabe vermindert, welches durch Indomethazinbehandlung, unterstützt durch hochregulierte proneurogene Signalwege, verhindert werden konnte. Dies war zudem mit einer verringerten zellulären Entzündungsreaktion assoziiert. Zusammenfassend weisen die Ergebnisse darauf hin, dass Neurone zu den biomechanischen Eigenschaften eines Gewebes beitragen. Daher könnte die MRE durch Erfassung verminderter viskoelastischer Eigenschaften bei neurodegenerativen Erkrankungen ein mögliches klinisch diagnostisches Werkzeug sein. Ferner verhinderte der COX-Hemmer Indomethazin eine geschädigte Neurogenese und Entzündung nach Dopamindepletion. Dies trägt dazu bei nichtselektive COX-Hemmer als mögliche Medikamente zur Verbesserung der Neurogenese in neurodegenerativen Erkrankungen in Betracht zu ziehen.Neurogenesis in the dentate gyrus (DG) of the hippocampus can be influenced by diverse factors, such as altered transmitter homeostasis or inflammation, and is also changed in neurodegenerative diseases. Mediators of inflammation are, for example, cytokines or prostaglandins. Last-mentioned mediators are catalyzed by the enzyme cyclooxygenase (COX). However, it is still not clear if COX inhibition and thus modulated inflammatory reactions influence adult neurogenesis in the DG in neurodegenerative diseases. In neurodegenerative diseases, altered neurogenesis or the loss of neurons could also lead to a changed composition of the cellular network and could be displayed in viscoelastic properties, which could be detected by parameters of the novel imaging technique magnetic resonance elastography (MRE). Altered viscoelastic parameters of the brain have already been observed in patients with neurodegenerative diseases, but to date only a few studies have researched the underlying cellular mechanisms. Here, we investigated the alterations of viscoelastic properties using MRE and possible underlying cellular mechanism in the hippocampus (study 1) and in the SN (study 2) by applying the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of dopamine depletion. Moreover, we evaluated the influence of the nonselective COX inhibitor indomethacin on adult hippocampal neurogenesis and neurogenic signaling pathways as well as inflammation in the DG and SN (study 3). Hippocampal neurogenesis and cellular inflammation were investigated using immunohistochemical stainings. Furthermore, alterations in neurogenesis-relevant signaling pathways were analyzed using quantitative polymerase chain reaction, and concentrations of cytokines were quantified by enzyme-linked immunosorbent assay. In the hippocampus, MPTP treatment caused a transiently increased amount of new progenitor cells resulting in a transiently increased percentage of new neurons leading to a temporarily higher viscoelasticity. In the SN, the loss of dopaminergic neurons led to a decrease of viscoelastic properties. At a later time point after MPTP administration, the number of new mature neurons was decreased in the DG. This could be prevented by indomethacin treatment, which was supported by upregulated proneurogenic signaling pathways, and was associated with a decreased cellular inflammation. In conclusion, the MRE and histological results show that neurons contribute to the biomechanical tissue characteristics. Thus, decreased viscoelastic properties in neurodegenerative diseases observed by MRE may be a potential approach for clinical diagnosis. Furthermore, the COX inhibitor indomethacin prevented impaired adult neurogenesis and inflammation after dopamine depletion. This contributes to the validation of nonselective COX inhibitors as a potential therapeutic drug to restore neurogenesis in neurodegenerative diseases

Total Pelvic Exenteration for Gynecologic Malignancies

Total pelvic exenteration (PE) is a radical operation, involving en bloc resection of pelvic organs, including reproductive structures, bladder, and rectosigmoid. In gynecologic oncology, it is most commonly indicated for the treatment of advanced primary or locally recurrent cancer. Careful patient selection and counseling are of paramount importance when considering someone for PE. Part of the evaluation process includes comprehensive assessment to exclude unresectable or metastatic disease. PE can be curative for carefully selected patients with gynecologic cancers. Major complications can be seen in as many as 50% of patients undergoing PE, underscoring the need to carefully discuss risks and benefits of this procedure with patients considering exenterative surgery

Increased nutrient supply to the Southern Ocean during the Holocene and its implications for the pre-industrial atmospheric CO₂ rise

A rise in the atmospheric CO2 concentration of ~20 parts per million over the course of the Holocene has long been recognized as exceptional among interglacials and is in need of explanation. Previous hypotheses involved natural or anthropogenic changes in terrestrial biomass, carbonate compensation in response to deglacial outgassing of oceanic CO2, and enhanced shallow water carbonate deposition. Here, we compile new and previously published fossil-bound nitrogen isotope records from the Southern Ocean that indicate a rise in surface nitrate concentration through the Holocene. When coupled with increasing or constant export production, these data suggest an acceleration of nitrate supply to the Southern Ocean surface from underlying deep water. This change would have weakened the ocean’s biological pump that stores CO2 in the ocean interior, possibly explaining the Holocene atmospheric CO2 rise. Over the Holocene, the circum-North Atlantic region cooled, and the formation of North Atlantic Deep Water appears to have slowed. Thus, the ‘seesaw’ in deep ocean ventilation between the North Atlantic and the Southern Ocean that has been invoked for millennial-scale events, deglaciations and the last interglacial period may have also operated, albeit in a more gradual form, over the Holocene

Surgical Management of Neuroendocrine Tumours of the Pancreas

International audienceNeuroendocrine tumours of the pancreas (pNET) are rare, accounting for 1-2% of all pancreatic neoplasms. They develop from pancreatic islet cells and cover a wide range of heterogeneous neoplasms. While most pNETs are sporadic, some are associated with genetic syndromes. Furthermore, some pNETs are 'functioning' when there is clinical hypersecretion of metabolically active peptides, whereas others are 'non-functioning'. pNET can be diagnosed at a localised stage or a more advanced stage, including regional or distant metastasis (in 50% of cases) mainly located in the liver. While surgical resection is the cornerstone of the curative treatment of those patients, pNET management requires a multidisciplinary discussion between the oncologist, radiologist, pathologist, and surgeon. However, the scarcity of pNET patients constrains centralised management in high-volume centres to provide the best patient-tailored approach. Nonetheless, no treatment should be initiated without precise diagnosis and staging. In this review, the steps from the essential comprehensive preoperative evaluation of the best surgical approach (open versus laparoscopic, standard versus sparing parenchymal pancreatectomy, lymphadenectomy) according to pNET staging are analysed. Strategies to enhance the short- and long-term benefit/risk ratio in these particular patients are discussed

Xyr1 (Xylanase Regulator 1) Regulates both the Hydrolytic Enzyme System and d-Xylose Metabolism in Hypocrea jecorina

Xyr1 (xylanase regulator 1) of the ascomycete Hypocrea jecorina (anamorph Trichoderma reesei) was recently demonstrated to play an essential role in the transcriptional regulation of the xyn1 (xylanase 1-encoding) gene expression. Consequently, this study reports on the deletion of the xyr1 gene from the H. jecorina genome. Comparative studies of the growth behavior of the different mutant strains (deleted and retransformed xyr1) grown on various carbon sources pointed to the strongly reduced ability of the xyr1 deletion strain to utilize d-xylose and xylan. Transcriptional analysis of the xyl1 (d-xylose reductase 1-encoding) gene as well as measurements of corresponding enzymatic activities gave evidence that Xyr1 takes part in the control of the fungal d-xylose pathway, in particular in the regulation of d-xylose reductase. It could be demonstrated that the uptake of d-xylose into the fungal cell is uninfluenced in the Δxyr1 strain. Furthermore, transcriptional regulation of the major hydrolytic enzyme-encoding genes xyn1 and xyn2 (xylanases 1 and 2), cbh1 and cbh2 (cellobiohydrolases 1 and 2), and egl1 (endoglucanase 1) is strictly dependent on Xyr1. Regulation of the respective genes via Xyr1 is not affected by the substances mediating induction (xylose, xylobiose, and sophorose) and is indispensable for all modes of gene expression (basal, derepressed, and induced). Moreover, Xyr1, it was revealed, activated transcriptional regulation of inducer-providing enzymes such as β-xylosidase BXLI and β-glucosidase BGLI but was not shown to be involved in the regulation of BGLII

Indomethacin promotes survival of new neurons in the adult murine hippocampus accompanied by anti-inflammatory effects following MPTP-induced dopamine depletion

Abstract Background Parkinson’s disease (PD) is characterized by dopaminergic cell loss and inflammation in the substantia nigra (SN) leading to motor deficits but also to hippocampus-associated non-motor symptoms such as spatial learning and memory deficits. The cognitive decline is correlated with impaired adult hippocampal neurogenesis resulting from dopamine deficit and inflammation, represented in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (MPTP) mouse model of PD. In the inflammatory tissue, cyclooxygenase (COX) is upregulated leading to an ongoing inflammatory process such as prostaglandin-mediated increased cytokine levels. Therefore, inhibition of COX by indomethacin may prevent the inflammatory response and the impairment of adult hippocampal neurogenesis. Methods Wildtype C57Bl/6 and transgenic Nestin-GFP mice were treated with MPTP followed by short-term or long-term indomethacin treatment. Then, aspects of inflammation and neurogenesis were evaluated by cell counts using immunofluorescence and immunohistochemical stainings in the SN and dentate gyrus (DG). Furthermore, hippocampal mRNA expression of neurogenesis-related genes of the Notch, Wnt, and sonic hedgehog signaling pathways and neurogenic factors were assessed, and protein levels of serum cytokines were measured. Results Indomethacin restored the reduction of the survival rate of new mature neurons and reduced the amount of amoeboid CD68+ cells in the DG after MPTP treatment. Indomethacin downregulated genes of the Wnt and Notch signaling pathways and increased neuroD6 expression. In the SN, indomethacin reduced the pro-inflammatory cellular response without reversing dopaminergic cell loss. Conclusion Indomethacin has a pro-neurogenic and thereby restorative effect and an anti-inflammatory effect on the cellular level in the DG following MPTP treatment. Therefore, COX inhibitors such as indomethacin may represent a therapeutic option to restore adult neurogenesis in PD

Dopaminergic Neurodegeneration in the Mouse Is Associated with Decrease of Viscoelasticity of Substantia Nigra Tissue.

The biomechanical properties of brain tissue are altered by histopathological changes due to neurodegenerative diseases like Parkinson's disease (PD). Such alterations can be measured by magnetic resonance elastography (MRE) as a non-invasive technique to determine viscoelastic parameters of the brain. Until now, the correlation between histopathological mechanisms and observed alterations in tissue viscoelasticity in neurodegenerative diseases is still not completely understood. Thus, the objective of this study was to evaluate (1) the validity of MRE to detect viscoelastic changes in small and specific brain regions: the substantia nigra (SN), midbrain and hippocampus in a mouse model of PD, and (2) if the induced dopaminergic neurodegeneration and inflammation in the SN is reflected by local changes in viscoelasticity. Therefore, MRE measurements of the SN, midbrain and hippocampus were performed in adult female mice before and at five time points after 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridin hydrochloride (MPTP) treatment specifically lesioning dopaminergic neurons in the SN. At each time point, additional mice were utilized for histological analysis of the SN. After treatment cessation, we observed opposed viscoelastic changes in the midbrain, hippocampus and SN with the midbrain showing a gradual rise and the hippocampus a distinct transient increase of viscous and elastic parameters, while viscosity and-to a lesser extent-elasticity in the SN decreased over time. The decrease in viscosity and elasticity in the SN was paralleled by a reduced number of neurons due to the MPTP-induced neurodegeneration. In conclusion, MRE is highly sensitive to detect local viscoelastic changes in specific and even small brain regions. Moreover, we confirmed that neuronal cells likely constitute the backbone of the adult brain mainly accounting for its viscoelasticity. Therefore, MRE could be established as a new potential instrument for clinical evaluation and diagnostics of neurodegenerative diseases

Fate of selectable marker DNA integrated into the genome of Nicotiana tabacum

To compare the effects of different transformation methods on the integration behavior and structural stability of integrated foreign genes in plant cells, tobacco protoplasts were transformed with Escherichia coli plasmid pLGV2103neo DNA using the Ca phosphate DNA coprecipitation technique. Parallel transformations were done by cocultivation with Agrobacterium tumefaciens harboring the Ti plasmid derivatives pGV3850::2103neo or pGV3850::1103neo. A comparison of the fine structure of the integrated donor DNA obtained by direct gene transfer and by cocultivation indicates that the donor DNA in cells transformed by the former technique undergoes structural changes and concatemerizations, while the DNA integrated by the latter procedure is often unaltered. The cotransformed nopaline synthase gene, which is present in the donor Ti plasmid DNA, was inactivated in two out of nine cases. Once integrated, the arrays of selectable marker DNA appear to be structurally stable under different cell culture and selection conditions, as well as after genetic transmission

Additional file 1: of Indomethacin promotes survival of new neurons in the adult murine hippocampus accompanied by anti-inflammatory effects following MPTP-induced dopamine depletion

Figure S1. Effects of dopamine depletion and indomethacin treatment on the stages of adult hippocampal neurogenesis. Neuronal development originates from a Nestin-positive, triangular-shaped stem cell (type 1). Then, neurogenesis progresses over the stages of the putative progenitor cells (type 2a, type 2b, and type 3) and ends in the NeuN-positive mature granule cell. Neurotoxic treatment leads to a decreased number of newly generated (type 2a cells) and mature neurons, whereas indomethacin treatment afterwards promotes the development towards mature neurons. MPTP: 1-methyl-4-(2′-methylphenyl)-1,2,3,6-tetrahydropyridine hydrochloride; NeuN: neuronal nuclei. (TIF 624 kb

Enhanced Adult Neurogenesis Increases Brain Stiffness: <i>In Vivo</i> Magnetic Resonance Elastography in a Mouse Model of Dopamine Depletion

<div><p>The mechanical network of the brain is a major contributor to neural health and has been recognized by in vivo magnetic resonance elastography (MRE) to be highly responsive to diseases. However, until now only brain softening was observed and no mechanism was known that reverses the common decrement of neural elasticity during aging or disease. We used MRE in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (MPTP) mouse model for dopaminergic neurodegeneration as observed in Parkinson’s disease (PD) to study the mechanical response of the brain on adult hippocampal neurogenesis as a robust correlate of neuronal plasticity in healthy and injured brain. We observed a steep transient rise in elasticity within the hippocampal region of up to over 50% six days after MPTP treatment correlating with increased neuronal density in the dentate gyrus, which could not be detected in healthy controls. Our results provide the first indication that new neurons reactively generated following neurodegeneration substantially contribute to the mechanical scaffold of the brain. Diagnostic neuroimaging may thus target on regions of the brain displaying symptomatically elevated elasticity values for the detection of neuronal plasticity following neurodegeneration.</p></div