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BACKGROUND CONTEXT Spinal arachnoid web (SAW) is a rare condition characterized by focal thickening of the arachnoid membrane causing displacement and compression of the spinal cord with progressive symptoms and neurological deficits. Recent reports and clinical experience suggest that SAW is a distinct entity with specific radiological findings and treatment strategies distinguishable from other arachnopathies and potential differential diagnoses. PURPOSE To better define the diagnostic and clinical features, treatment options and outcomes of surgically treated SAW. STUDY DESIGN Multicentric retrospective cohort study. PATIENT SAMPLE Twelve cases of SAW surgically treated at three different centers. OUTCOME MEASURES Self-reported and neurological outcome measurements (pain, sensory-motor deficits, vegetative dysfunctions) were assessed at follow-up timepoints. METHODS Retrospective review of prospectively collected data on all patients surgically treated for SAW from three participating neurosurgical centers between 2014 and 2020. Clinicopathological data, including neurological presentation, radiological and histological findings and outcome data were analyzed. RESULTS Twelve radiologically and surgically confirmed cases of SAW were analyzed. Mean patient age was 54.7 [±12.7], 67% were male. All SAWs were located in the posterior thoracic dural sac. On magnetic resonance imaging (MRI), the "scalpel sign" - a characteristic focal dorsal indentation of the spinal cord resembling a scalpel blade - was identified in all patients. A focal intramedullary syrinx was present in 83%. Preoperative clinical symptoms included signs of myelopathy, pain, weakness and sensory loss, most commonly affecting the trunk/upper back or lower extremities. Laminectomy or laminoplasty with intradural excision of the SAW was the surgical treatment of choice in all cases. Intraoperative ultrasound was valuable to visualize the cerebrospinal fluid (CSF) flow obstruction, confirm the SAW location before dura incision and to control adequacy of resection. After surgery, sensory loss and weakness in particular showed significant improvement. CONCLUSIONS The present study comprises the largest series of surgically treated SAW, underscoring the unique clinical, radiographic, histopathological, and surgical findings. We want to emphasize SAW being a distinct entity of spinal arachnopathy with a favorable long-term outcome if diagnosed correctly and treated surgically. Intraoperative ultrasound aids visualizing the SAW before dural incision, as well as verifying restored CSF flow after resection.

The study aims to investigate the performance characteristics of the enantiomers of 11C-Me-NB1, a recently reported PET imaging probe that targets the GluN2B subunit of N-methyl-d-aspartate (NMDA) receptors. Methods: Reference compound Me-NB1 (inhibition constant for hGluN1/GluN2B, 5.4 nM) and the phenolic precursor were prepared via multistep synthesis. Following chiral resolution by high-performance liquid chromatography, enantiopure precursor compounds, (R)-NB1 and (S)-NB1, were labeled with 11C and validated in rodents using in vitro/ex vivo autoradiography, PET experiments, and dose-response studies. To illustrate the translational relevance, (R)- 11C-Me-NB1 was validated in autoradiographic studies using postmortem human GluN2B-rich cortical and GluN2B-deficient cerebellar brain slices. To determine target engagement, receptor occupancy was assessed at different plasma concentrations of CP101,606, a GluN2B receptor antagonist. Results: The radiosynthesis of (R)- and (S)- 11C-Me-NB1 was accomplished in 42% ± 9% (decay-corrected) radiochemical yields. Molar activity ranged from 40 to 336 GBq/μmol, and an excellent radiochemical purity of greater than 99% was achieved. Although (R)- 11C-Me-NB1 displayed heterogeneous accumulation with high selectivity for the GluN2B-rich forebrain, (S)- 11C-Me-NB1 revealed a homogeneous distribution across all brain regions in rodent brain autoradiograms and predominantly exhibited σ1-receptor binding. Similar to rodent brain, (R)- 11C-Me-NB1 showed in postmortem human brain tissues higher binding in the cortex than in the cerebellum. Coincubation of the GluN2B-antagonist CERC-301 (1 μM) reduced cortical but not cerebellar binding, demonstrating the specificity of (R)- 11C-Me-NB1 binding to the human GluN2B-containing NMDA receptor. In vivo specificity of (R)- 11C-Me-NB1 in the GluN2B-expressing cortex, striatum, thalamus, and hippocampus was demonstrated by PET imaging in rodents. Applying GluN2B-antagonist eliprodil, an evident dose-response behavior was observed with (R)- 11C-Me-NB1 but not with (S)- 11C-Me-NB1. Our findings further underline the tightrope walk between GluN2B- and σ1-receptor-targeted imaging, illustrated by the entirely different receptor binding behavior of the 2 radioligand enantiomers. Conclusion: (R)- 11C-Me-NB1 is a highly selective and specific PET radioligand for imaging the GluN2B subunit of the NMDA receptor. The entirely different receptor binding behavior of (R)- 11C-Me-NB1 and (S)- 11C-Me-NB1 raises awareness of a delicate balance that is underlying the selective targeting of either GluN2B-carrying NMDA or σ1-receptors.

Mycosis fungoides (MF) is a presentation of primary cutaneous T-cell lymphoma with adverse prognosis for patients with advanced stages of the disease. Refractory disease and advanced-stage disease require systemic therapy. We reported a rare case of an atypical predominantly CD8+ folliculotropic MF, a subtype of MF with poorer prognosis, in a 59-year-old woman. She was initially diagnosed with MF restricted to the skin, of T3N0M0B0/stage IIB according to the current World Health Organization–European Organisation for Research and Treatment of Cancer classification. First-line treatment with local percutaneous radiotherapy in combination with systemic interferon alfa-2a resulted in complete remission. However, 21 months later the disease progressed to T3N0M1B0/stage IVB with development of cerebral manifestation and thus very poor prognosis. Allogeneic stem cell transplantation (SCT) was not a therapeutic option due to the lack of a suitable donor. We initiated methotrexate and cytarabine chemotherapy, followed by high-dose chemotherapy with thiotepa and carmustine with autologous SCT. Despite rapid response and complete remission of the cerebral lesions, disease recurrence of the skin occurred soon after. Readministration of interferon alfa-2a as a maintenance treatment after the salvage autologous SCT resulted in a complete remission during a follow-up period of 32.5 months after autologous SCT. After that, the disease relapsed with simultaneous skin and cerebral lesions. Despite immediate intrathecal and subsequently intravenous administration of high-dose methotrexate and cytarabin, we observed further progressed and the patient deceased 3.5 months after this second fulminant recurrence and in total 36 months after autologous SCT transplantation.

Simple Summary Osteosarcoma, Ewing’s sarcoma, and H3K27M-mutant diffuse midline glioma are rare but aggressive malignancies occurring mainly in children. Due to their rareness and often fatal course, drug development is challenging. Here, we repurposed the existing drugs dinutuximab and eliglustat and investigated their potential to directly target or indirectly modulate the tumor cell-specific ganglioside GD2. Our data suggest that targeting and/or modulating tumor cell-specific GD2 may offer a new therapeutic strategy for the above mentioned tumor entities. Abstract The ganglioside GD2 is an important target in childhood cancer. Nevertheless, the only therapy targeting GD2 that is approved to date is the monoclonal antibody dinutuximab, which is used in the therapy of neuroblastoma. The relevance of GD2 as a target in other tumor entities remains to be elucidated. Here, we analyzed the expression of GD2 in different pediatric tumor entities by flow cytometry and tested two approaches for targeting GD2. H3K27M-mutant diffuse midline glioma (H3K27M-mutant DMG) samples showed the highest expression of GD2 with all cells strongly positive for the antigen. Ewing’s sarcoma (ES) samples also showed high expression, but displayed intra- and intertumor heterogeneity. Osteosarcoma had low to intermediate expression with a high percentage of GD2-negative cells. Dinutuximab beta in combination with irinotecan and temozolomide was used to treat a five-year-old girl with refractory ES. Disease control lasted over 12 months until a single partially GD2-negative intracranial metastasis was detected. In order to target GD2 in H3K27M-mutant DMG, we blocked ganglioside synthesis via eliglustat, since dinutuximab cannot cross the blood–brain barrier. Eliglustat is an inhibitor of glucosylceramide synthase, and it is used for treating children with Gaucher’s disease. Eliglustat completely inhibited the proliferation of primary H3K27M-mutant DMG cells in vitro. In summary, our data provide evidence that dinutuximab might be effective in tumors with high GD2 expression. Moreover, disrupting the ganglioside metabolism in H3K27M-mutant DMG could open up a new therapeutic option for this highly fatal cancer.

Aircraft noise induces vascular and cerebral inflammation and oxidative stress causing hypertension and cardiovascular/cerebral dysfunction. With the present studies, we sought to determine the role of myeloid cells in the vascular vs. cerebral consequences of exposure to aircraft noise. Toxin-mediated ablation of lysozyme M+ (LysM+) myeloid cells was performed in LysMCreiDTR mice carrying a cre-inducible diphtheria toxin receptor. In the last 4d of toxin treatment, the animals were exposed to noise at maximum and mean sound pressure levels of 85 and 72 dB(A), respectively. Flow cytometry analysis revealed accumulation of CD45+, CD11b+, F4/80+, and Ly6G−Ly6C+ cells in the aortas of noise-exposed mice, which was prevented by LysM+ cell ablation in the periphery, whereas brain infiltrates were even exacerbated upon ablation. Aircraft noise-induced increases in blood pressure and endothelial dysfunction of the aorta and retinal/mesenteric arterioles were almost completely normalized by ablation. Correspondingly, reactive oxygen species in the aorta, heart, and retinal/mesenteric vessels were attenuated in ablated noise-exposed mice, while microglial activation and abundance in the brain was greatly increased. Expression of phagocytic NADPH oxidase (NOX-2) and vascular cell adhesion molecule-1 (VCAM-1) mRNA in the aorta was reduced, while NFκB signaling appeared to be activated in the brain upon ablation. In sum, we show dissociation of cerebral and peripheral inflammatory reactions in response to aircraft noise after LysM+ cell ablation, wherein peripheral myeloid inflammatory cells represent a dominant part of the pathomechanism for noise stress-induced cardiovascular effects and their central nervous counterparts, microglia, as key mediators in stress responses.

Coronavirus disease 19 (COVID‐19) is a rapidly evolving pandemic caused by the coronavirus Sars‐CoV‐2. Clinically manifest central nervous system symptoms have been described in COVID‐19 patients and could be the consequence of commonly associated vascular pathology, but the detailed neuropathological sequelae remain largely unknown. A total of six cases, all positive for Sars‐CoV‐2, showed evidence of cerebral petechial hemorrhages and microthrombi at autopsy. Two out of six patients showed an elevated risk for disseminated intravascular coagulopathy according to current criteria and were excluded from further analysis. In the remaining four patients, the hemorrhages were most prominent at the grey and white matter junction of the neocortex, but were also found in the brainstem, deep grey matter structures and cerebellum. Two patients showed vascular intramural inflammatory infiltrates, consistent with Sars‐CoV‐2‐associated endotheliitis, which was associated by elevated levels of the Sars‐CoV‐2 receptor ACE2 in the brain vasculature. Distribution and morphology of patchy brain microbleeds was clearly distinct from hypertension‐related hemorrhage, critical illness‐associated microbleeds and cerebral amyloid angiopathy, which was ruled out by immunohistochemistry. Cerebral microhemorrhages in COVID‐19 patients could be a consequence of Sars‐ CoV‐2‐induced endotheliitis and more general vasculopathic changes and may correlate with an increased risk of vascular encephalopathy., Clinically manifest central nervous system symptoms are common in COVID‐19 patients but their causes are still unknown. We present here four patients who tested positive for Sars‐CoV‐2 with cerebral haemorrhages which were most prominent at the grey and white matter junction of the neocortex and the brainstem. We present evidence of intracerebral endotheliitis in COVID‐19 patients which could predispose to more general vasculopathic changes and may correlate with an increased risk of vascular encephalopathy.

Background Acute respiratory distress syndrome (ARDS) is an important disease with a high incidence among patients admitted to intensive care units. Over the last decades, the survival of critically ill patients has improved; however, cognitive deficits are among the long-term sequelae. We hypothesize that acute lung injury leads to upregulation of cerebral cytokine synthesis. Methods After approval of the institutional and animal care committee, 20 male pigs were randomized to one of three groups: (1) Lung injury by oleic acid injection (OAI), (2) ventilation only (CTR) or (3) untreated. We compared neuronal numbers, proportion of neurons with markers for apoptosis, activation state of Iba-1 stained microglia cells and cerebral mRNA levels of different cytokines between the groups 18 hours after onset of lung injury. Results We found an increase in hippocampal TNFalpha (p p p p p Conclusion Hippocampal cytokine transcription increases within 18 hours after the induction of acute lung injury with histological evidence of neuronal damage. It remains to be elucidated if increased cytokine mRNA synthesis plays a role in the cognitive decline observed in survivors of ARDS.

Antiphospholipid antibodies (aPL), assumed to cause antiphospholipid syndrome (APS), are notorious for their heterogeneity in targeting phospholipids and phospholipid-binding proteins. The persistent presence of Lupus anticoagulant and/or aPL against cardiolipin and/or β2-glycoprotein I have been shown to be independent risk factors for vascular thrombosis and pregnancy morbidity in APS. aPL production is thought to be triggered by–among other factors–viral infections, though infection-associated aPL have mostly been considered non-pathogenic. Recently, the potential pathogenicity of infection-associated aPL has gained momentum since an increasing number of patients infected with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has been described with coagulation abnormalities and hyperinflammation, together with the presence of aPL. Here, we present data from a multicentric, mixed-severity study including three cohorts of individuals who contracted SARS-CoV-2 as well as non-infected blood donors. We simultaneously measured 10 different criteria and non-criteria aPL (IgM and IgG) by using a line immunoassay. Further, IgG antibody response against three SARS-CoV-2 proteins was investigated using tripartite automated blood immunoassay technology. Our analyses revealed that selected non-criteria aPL were enriched concomitant to or after an infection with SARS-CoV-2. Linear mixed-effects models suggest an association of aPL with prothrombin (PT). The strength of the antibody response against SARS-CoV-2 was further influenced by SARS-CoV-2 disease severity and sex of the individuals. In conclusion, our study is the first to report an association between disease severity, anti-SARS-CoV-2 immunoreactivity, and aPL against PT in patients with SARS-CoV-2., Author summary An infection with SARS-CoV-2 affects patients differently. While some individuals do not develop any symptoms at all, others become seriously ill, displaying signs of hypercoagulation with involvement of different organ systems. The immune response triggered upon infection may comprise both protective as well as detrimental elements. Among the latter, antibodies targeting a wide range of self-proteins have been evidenced. Our research has focused on autoantibodies targeting phospholipids and phospholipid-binding proteins, held responsible for an increased tendency to thrombosis in an autoimmune disease called antiphospholipid syndrome. Using cohorts from different centres, including patients of mixed disease severities, we found that IgM antibodies targeting prothrombin and β2-glycoprotein I are enriched upon infection. Using a linear mixed-effects model, we further established that anti-prothrombin IgM autoantibodies emerge in proportion to the strength of the antibody response elicited against SARS-CoV-2 proteins, with disease severity and sex as additional contributors. Further research is warranted to investigate the relation between infection with SARS-CoV-2, hypercoagulation, and the presence of autoantibodies directed against prothrombin.

H3K27M-mutant diffuse midline glioma (H3K27M-mutant DMG) is a rare malignant brain tumour entity in children and adults with a median overall survival of around 12 months. Genomic and proteomic analysis may help to identify new target structures, however not all relevant targets are covered by these analyses. Glycosphingolipids and particularly gangliosides play a major role in brain development and have been involved in the pathology of brain tumours. The conversion of ceramide to glucosylceramide via glucosylceramide synthase (GCS) is one of the first steps in the synthesis of glycosphingolipids. Therefore, targeting GCS will inhibit their synthesis. Here we analysed the glycosphingolipids composition and tested GCS inhibitors in an in vitro model of H3K27M-mutant DMG. Methods: H3K27M-mutant DMG primary cells were established from needle biopsies of two paediatric patients and characterised by immunohistochemistry. Glycosphingolipids were analysed by thin layer chromatography, liquid chromatography-coupled tandem mass spectrometry and flow cytometry. The effect of the GCS inhibitor eliglustat on the cell proliferation was examined. Results. The primary cells maintained the features of the tumour of origin, including the H3K27M mutation. Neutral glycosphingolipids with 1 to 4 monosaccharides and the ganglioside GD2 were expressed at high concentration. Eliglustat completely abrogated the proliferation of the H3K27M-mutant DMG primary cells. Conclusions. The glycosphingolipids oncometabolism represents a novel target in H3K27M-mutant DMG. The GCS inhibitors eliglusat and miglustat are already used to treat paediatric patients with the lysosomal storage disorders Niemann Pick’s and Gaucher′s disease and miglustat can cross the blood-brain barrier. Thus, our finding may accelerate the access of H3K27M-mutant DMG patients to novel innovative clinical studies based on the inhibition of the glycosphingolipids metabolism.

Mycosis fungoides (MF) is a primary cutaneous T-cell lymphoma with unfavourable prognosis for patients with advanced stages of the disease. Refractory disease and advanced-stage disease require systemic therapy. We report on a rare case of an atypical predominantly CD8 + folliculotropic MF, a subtype of MF with poorer prognosis, in a 59-year-old woman. She was initially diagnosed with MF restricted to the skin, of T3N0M0B0/stage IIB according to the current World Health Organization–European Organisation for Research and Treatment of Cancer classification. First-line treatment with local percutaneous radiotherapy in combination with systemic interferon alfa-2a resulted in complete remission. However, 21 months later the disease progressed to T3N0M1B0/stage IVB with development of cerebral manifestation and thus very poor prognosis. Allogeneic stem cell transplantation (SCT) was not a therapeutic option due to the lack of a suitable donor. We initiated methotrexate and cytarabine chemotherapy, followed by high-dose chemotherapy with thiotepa and carmustine with autologous SCT. Despite rapid response and complete remission of the cerebral lesions, disease recurrence of the skin occurred soon after. Interestingly, readministration of interferon alfa-2a as a maintenance treatment after the salvage autologous SCT resulted in a durable complete remission during the follow-up period of currently 17 months after autologous SCT.

PURPOSE Using G-CSF deficient mice we recently demonstrated neuroprotective properties of endogenous G-CSF after ischemic stroke. The present follow-up study was designed to check, whether specific alterations in ligand binding densities of excitatory glutamate or inhibitory GABAA receptors may participate in this effect. METHODS Three groups of female mice were subjected to 45 minutes of MCAO: wildtype, G-CSF deficient and G-CSF deficient mice substituted with G-CSF. Infarct volumes were determined after 24 hours and quantitative in vitro receptor autoradiography was performed using [3H]MK-801, [3H]AMPA and [3H]muscimol for labeling of NMDA, AMPA and GABAA receptors, respectively. Ligand binding densities were analyzed in regions in the ischemic core, peri-infarct areas and corresponding contralateral regions. RESULTS Infarct volumes did not significantly differ between the experimental groups. Ligand binding densities of NMDA and GABAA receptors were widely in the same range. However, AMPA receptor binding densities in G-CSF deficient mice were substantially enhanced compared to wildtype mice. G-CSF substitution in mice lacking G-CSF largely reversed this effect. CONCLUSIONS Although infarct volumes did not differ 24 hours after ischemia the increase of AMPA receptor binding densities in G-CSF deficient mice may explain the bigger infarcts previously observed at later time-points with the same stroke model.

Arterial hypertension is the most important risk factor for the development of cardiovascular disease. Recently, aircraft noise has been shown to be associated with elevated blood pressure, endothelial dysfunction, and oxidative stress. Here, we investigated the potential exacerbated cardiovascular effects of aircraft noise in combination with experimental arterial hypertension. C57BL/6J mice were infused with 0.5 mg/kg/d of angiotensin II for 7 days, exposed to aircraft noise for 7 days at a maximum sound pressure level of 85 dB(A) and a mean sound pressure level of 72 dB(A), or subjected to both stressors. Noise and angiotensin II increased blood pressure, endothelial dysfunction, oxidative stress and inflammation in aortic, cardiac and/or cerebral tissues in single exposure models. In mice subjected to both stressors, most of these risk factors showed potentiated adverse changes. We also found that mice exposed to both noise and ATII had increased phagocytic NADPH oxidase (NOX-2)-mediated superoxide formation, immune cell infiltration (monocytes, neutrophils and T cells) in the aortic wall, astrocyte activation in the brain, enhanced cytokine signaling, and subsequent vascular and cerebral oxidative stress. Exaggerated renal stress response was also observed. In summary, our results show an enhanced adverse cardiovascular effect between environmental noise exposure and arterial hypertension, which is mainly triggered by vascular inflammation and oxidative stress. Mechanistically, noise potentiates neuroinflammation and cerebral oxidative stress, which may be a potential link between both risk factors. The results indicate that a combination of classical (arterial hypertension) and novel (noise exposure) risk factors may be deleterious for cardiovascular health., Graphical abstract Image 1, Highlights • Noise exposure causes non-auditory cardiovascular/cerebral adverse health effects by oxidative stress and inflammation. • Aircraft noise causes exacerbated adverse effects on blood pressure and endothelial dysfunction in hypertensive mice. • Aircraft noise and hypertension potentiate inflammation, ROS formation and oxidative damage in the brain, vessels and heart. • Aircraft noise and hypertension seem to have enhanced adverse effects on stress responses in different organs.

We report two cases of olfactory neuropathy diagnosed at autopsy in patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. One patient experienced anosmia. Information about anosmia was not available in the other patient. Patient 1, a man aged 70 years, and patient 2, a man aged 79 years, both tested positive for SARS-CoV-2. Patient 1 was a renal transplant recipient with coronary artery disease and arterial hypertension. He developed progressive respiratory failure due to COVID-19 pneumonia and required mechanical ventilation. He was treated with hydroxychloroquine (total 1600 mg). Patient 2 was previously diagnosed with severe pulmonary hypertension and was admitted with fever, cough, and increasing dyspnoea as well as loss of taste and smell. He was also treated with hydroxychloroquine (total 1600 mg); however, he declined invasive treatment. Patient 1 died 8 days after hospital admission; patient 2 died 6 days after hospital admission.

Aims Aircraft noise causes endothelial dysfunction, oxidative stress, and inflammation. Transportation noise increases the incidence of coronary artery disease, hypertension, and stroke. The underlying mechanisms are not well understood. Herein, we investigated effects of phagocyte-type NADPH oxidase (Nox2) knockout and different noise protocols (around-the-clock, sleep/awake phase noise) on vascular and cerebral complications in mice. Methods and results C57BL/6j and Nox2 −/− (gp91phox −/−) mice were exposed to aircraft noise (maximum sound level of 85 dB(A), average sound pressure level of 72 dB(A)) around-the-clock or during sleep/awake phases for 1, 2, and 4 days. Adverse effects of around-the-clock noise on the vasculature and brain were mostly prevented by Nox2 deficiency. Around-the-clock aircraft noise of the mice caused the most pronounced vascular effects and dysregulation of Foxo3/circadian clock as revealed by next generation sequencing (NGS), suggesting impaired sleep quality in exposed mice. Accordingly, sleep but not awake phase noise caused increased blood pressure, endothelial dysfunction, increased markers of vascular/systemic oxidative stress, and inflammation. Noise also caused cerebral oxidative stress and inflammation, endothelial and neuronal nitric oxide synthase (e/nNOS) uncoupling, nNOS mRNA and protein down-regulation, and Nox2 activation. NGS revealed similarities in adverse gene regulation between around-the-clock and sleep phase noise. In patients with established coronary artery disease, night-time aircraft noise increased oxidative stress, and inflammation biomarkers in serum. Conclusion Aircraft noise increases vascular and cerebral oxidative stress via Nox2. Sleep deprivation and/or fragmentation caused by noise triggers vascular dysfunction. Thus, preventive measures that reduce night-time aircraft noise are warranted.

The study aims to investigate the performance characteristics of the enantiomers of

Summary Multiple sclerosis is an autoimmune disease that is caused by the interplay of genetic, particularly the HLA-DR15 haplotype, and environmental risk factors. How these etiologic factors contribute to generating an autoreactive CD4+ T cell repertoire is not clear. Here, we demonstrate that self-reactivity, defined as “autoproliferation” of peripheral Th1 cells, is elevated in patients carrying the HLA-DR15 haplotype. Autoproliferation is mediated by memory B cells in a HLA-DR-dependent manner. Depletion of B cells in vitro and therapeutically in vivo by anti-CD20 effectively reduces T cell autoproliferation. T cell receptor deep sequencing showed that in vitro autoproliferating T cells are enriched for brain-homing T cells. Using an unbiased epitope discovery approach, we identified RASGRP2 as target autoantigen that is expressed in the brain and B cells. These findings will be instrumental to address important questions regarding pathogenic B-T cell interactions in multiple sclerosis and possibly also to develop novel therapies., Graphical Abstract, Highlights • Autoproliferation of CD4+ T cells and B cells is involved in multiple sclerosis • The main genetic factor of MS, HLA-DR15, plays a central role in autoproliferation • Memory B cells drive autoproliferation of Th1 brain-homing CD4+ T cells • Autoproliferating T cells recognize antigens expressed in B cells and brain lesions, Memory B cells drive proliferation of self-reactive brain-homing CD4+ T cells, which recognize autoantigens expressed in B cells and in brain lesions with target potential in multiple sclerosis.

INTRODUCTION:The acute respiratory distress syndrome is not only associated with a high mortality, but also goes along with cognitive impairment in survivors. The cause for this cognitive impairment is still not clear. One possible mechanism could be cerebral inflammation as result of a "lung-brain-crosstalk". Even mechanical ventilation itself can induce cerebral inflammation. We hypothesized, that an acute lung injury aggravates the cerebral inflammation induced by mechanical ventilation itself and leads to neuronal damage. METHODS:After approval of the institutional and state animal care committee 20 pigs were randomized to one of three groups: lung injury by central venous injection of oleic acid (n = 8), lung injury by bronchoalveolar lavage in combination with one hour of injurious ventilation (n = 8) or control (n = 6). Brain tissue of four native animals from a different study served as native group. For six hours all animals were ventilated with a tidal volume of 7 ml kg-1 and a scheme for positive end-expiratory pressure and inspired oxygen fraction, which was adapted from the ARDS network tables. Afterwards the animals were killed and the brains were harvested for histological (number of neurons and microglia) and molecular biologic (TNFalpha, IL-1beta, and IL-6) examinations. RESULTS:There was no difference in the number of neurons or microglia cells between the groups. TNFalpha was significantly higher in all groups compared to native (p < 0.05), IL-6 was only increased in the lavage group compared to native (p < 0.05), IL-1beta showed no difference between the groups. DISCUSSION:With our data we can confirm earlier results, that mechanical ventilation itself seems to trigger cerebral inflammation. This is not aggravated by acute lung injury, at least not within the first 6 hours after onset. Nevertheless, it seems too early to dismiss the idea of lung-injury induced cerebral inflammation, as 6 hours might be just not enough time to see any profound effect.

The antiphospholipid syndrome (APS) is an autoimmune disease characterized by the presence of antiphospholipid antibodies, which may trigger vascular thrombosis with consecutive infarcts. However, cognitive dysfunctions representing one of the most commonest neuropsychiatric symptoms are frequently present despite the absence of any ischemic brain lesions. Data on the structural and functional basis of the neuropsychiatric symptoms are sparse. To examine the effect of APS on hippocampal neurogenesis and on white matter, we induced experimental APS (eAPS) in adult female Balb/C mice by immunization with β2-glycoprotein 1. To investigate cell proliferation in the dentate gyrus granular cell layer (DG GCL), eAPS and control mice (n = 5, each) were injected with 5-bromo-2′-deoxyuridine (BrdU) once a day for 10 subsequent days. Sixteen weeks after immunization, eAPS resulted in a significant reduction of BrdU-positive cells in the DG GCL compared to control animals. However, double staining with doublecortin and NeuN revealed a largely preserved neurogenesis. Ultrastructural analysis of corpus callosum (CC) axons in eAPS (n = 6) and control mice (n = 7) revealed no significant changes in CC axon diameter or g-ratio. In conclusion, decreased cellular proliferation in the hippocampus of eAPS mice indicates a limited regenerative potential and may represent one neuropathological substrate of cognitive changes in APS while evidence for alterations of white matter integrity is lacking.

Neuronal growth regulator 1 (NEGR1), a member of the immunoglobulin superfamily cell adhesion molecule subgroup IgLON, has been implicated in neuronal growth and connectivity. In addition, genetic variants in or near the NEGR1 locus have been associated with obesity and more recently with learning difficulties, intellectual disability and psychiatric disorders. However, experimental evidence is lacking to support a possible link between NEGR1, neuronal growth and behavioral abnormalities. Initial expression analysis of NEGR1 mRNA in C57Bl/6 wildtype (WT) mice by in situ hybridization demonstrated marked expression in the entorhinal cortex (EC) and dentate granule cells. In co-cultures of cortical neurons and NSC-34 cells overexpressing NEGR1, neurite growth of cortical neurons was enhanced and distal axons occupied an increased area of cells overexpressing NEGR1. Conversely, in organotypic slice co-cultures, Negr1-knockout (KO) hippocampus was less permissive for axons grown from EC of β-actin-enhanced green fluorescent protein (EGFP) mice compared to WT hippocampus. Neuroanatomical analysis revealed abnormalities of EC axons in the hippocampal dentate gyrus (DG) of Negr1-KO mice including increased numbers of axonal projections to the hilus. Neurotransmitter receptor ligand binding densities, a proxy of functional neurotransmitter receptor abundance, did not show differences in the DG of Negr1-KO mice but altered ligand binding densities to NMDA receptor and muscarinic acetylcholine receptors M1 and M2 were found in CA1 and CA3. Activity behavior, anxiety-like behavior and sensorimotor gating were not different between genotypes. However, Negr1-KO mice exhibited impaired social behavior compared to WT littermates. Moreover, Negr1-KO mice showed reversal learning deficits in the Morris water maze and increased susceptibility to pentylenetetrazol (PTZ)-induced seizures. Thus, our results from neuronal growth assays, neuroanatomical analyses and behavioral assessments provide first evidence that deficiency of the psychiatric disease-associated Negr1 gene may affect neuronal growth and behavior. These findings might be relevant to further evaluate the role of NEGR1 in cognitive and psychiatric disorders.

Development of vasogenic brain edema is a key event contributing to mortality after subarachnoid hemorrhage (SAH). The precise underlying mechanisms at the neurovascular level that lead to disruption of the blood-brain barrier (BBB) are still unknown. Activation of myosin light chain kinases (MLCK) may result in change of endothelial cell shape and opening of the intercellular gap with subsequent vascular leakage. Male C57Bl6 mice were subjected to endovascular perforation. Brain water content was determined by wet-dry ratio and BBB integrity by Evans-Blue extravasation. The specific MLCK inhibitor ML-7 was administered to the mice to determine the role of the contractile apparatus of the neurovascular unit in determining brain water content, BBB integrity, neurofunctional outcome, brain damage, and survival at 7 days after SAH. Inhibition of MLCK significantly reduced BBB permeability (Evans Blue extravasation − 28%) and significantly decreased edema formation in comparison with controls (− 2%). MLCK-treated mice showed reduced intracranial pressure (− 53%), improved neurological outcome at 24 h and 48 h after SAH, and reduced 7-day mortality. Tight junction proteins claudin-5 and zonula occludens-1 levels were not influenced by ML-7 at 24 h after insult. The effect of ML-7 on pMLC was confirmed in brain endothelial cell culture (bEnd.3 cells) subjected to 4-h oxygen-glucose deprivation. The present study indicates that MLCK contributes to blood-brain barrier dysfunction after SAH by a mechanism that does not involve modulation of tight junction protein levels, but via activation of the contractile apparatus of the endothelial cell skeleton. This underlying mechanism may be a promising target for the treatment of SAH. Electronic supplementary material The online version of this article (10.1007/s12975-018-0677-0) contains supplementary material, which is available to authorized users.

Experimental antiphospholipid syndrome (eAPS) in Balb/c mice causes neuropsychiatric abnormalities including hyperactivity, increased explorative behavior and cognitive deficits. Recently, we have demonstrated that these behavioral changes were linked to an upregulation of serotonergic 5-HT1A receptor binding densities in cortical and hippocampal regions while excitatory and inhibitory neurotransmitter receptors remain largely unchanged. To examine whether the observed behavioral features depend on a critical antibody concentration, mice with only moderately enhanced antiphospholipid antibodies (aPL), about 50–80% of high levels, were analyzed and compared to controls. The staircase test was used to test animals for hyperactivity and explorative behavior. The brains were analyzed for tissue integrity and inflammation. Ligand binding densities of NMDA, AMPA, GABAA, 5-HT1A, M1 and M2 muscarinic acetylcholine receptors, respectively, were analyzed by in vitro receptor autoradiography and compared to brains of mice from our previous study with high levels of aPL. Mice with only moderately enhanced aPL did not develop significant behavioral changes. Brain parenchyma remained intact and neither inflammation nor glial activation was detectable. However, there was a significant decrease of NMDA receptor binding densities in the motor cortex as well as an increase in M1 binding densities in cortical and hippocampal regions, whereas the other receptors analyzed were not altered. Lack of neuropsychiatric symptoms may be due to modulations of receptors resulting in normal behavior. In conclusion, our results support the hypothesis that high levels of aPL are required for the manifestation of neuropsychiatric involvement while at lower antibody levels compensatory mechanisms may preserve normal behavior.

The granulocyte colony-stimulating factor (G-CSF), being a member of the hematopoietic growth factor family, is also critically involved in controlling proliferation and differentiation of neural stem cells. Treatment with G-CSF has been shown to result in substantial neuroprotective and neuroregenerative effects in various experimental models of acute and chronic diseases of the central nervous system. Although G-CSF has been tested in a clinical study for treatment of acute ischemic stroke, there is only fragmentary data on the distribution of this cytokine and its receptor in the human brain. Therefore, the present study was focused on the immunohistochemical analysis of the protein expression of G-CSF and its receptor (G-CSF R) in the adult human brain. Since G-CSF has been shown not only to exert neuroprotective effects in animal models of Alzheimer's disease (AD) but also to be a candidate for clinical treatment, we have also placed an emphasis on the regulation of these molecules in this neurodegenerative disease. One major finding is that both G-CSF and G-CSF R were ubiquitously but not uniformly expressed in neurons throughout the CNS. Protein expression of G-CSF and G-CSF R was not restricted to neurons but was also detectable in astrocytes, ependymal cells, and choroid plexus cells. However, the distribution of G-CSF and G-CSF R did not substantially differ between AD brains and control, even in the hippocampus, where early neurodegenerative changes typically occur.

Objective: Limited data are available on the influence of sedation for critical care therapy with the widely used anesthetic propofol on recovery from acute traumatic brain injury. To establish the influence of propofol on endogenous neurogenesis and functional recovery after traumatic brain injury, rats were sedated with propofol either during or 2 hours after experimental traumatic brain injury. Design: Randomized controlled animal study. Setting: University research laboratory. Subjects: One hundred sixteen male Sprague Dawley rats. Interventions: Mechanical brain lesion by controlled cortical impact. Measurements and Main Results: This study investigated the dose-dependent influence of propofol (36 or 72 mg/kg/hr) either during controlled cortical impact induction or in a delayed application protocol 2 hours after experimental traumatic brain injury. Infusion of propofol resulted in 1) aggravation of neurologic dysfunction, 2) increased 28-day mortality rate, and 3) impaired posttraumatic neurogenesis (5-bromo-2-deoxyuridine + NeuN-positive cells). Application of propofol during trauma induction afforded a significant stronger effect in the high-dose group compared with low-dose propofol. In the posttrauma protocol, animals were sedated with sevoflurane during the controlled cortical impact injury, and propofol was given after an awake phase. In these animals, propofol increased mortality rate and impaired neurologic function and neurogenesis compared with animals without delayed propofol anesthesia. Conclusions: The results show that propofol may prevent or limit reparative processes in the early-phase postinjury. The results therefore indicate that anesthetics may be potentially harmful not only in very young mammalians but also in adult animals following acute cerebral injuries. The results provide first evidence for an altered sensitivity for anesthesia-related negative effects on neurogenesis, functional outcome, and survival in adult rats with brain lesions.

Multiple sclerosis is a demyelinating autoimmune disease of the CNS. Its animal model experimental autoimmune encephalomyelitis is commonly induced by active immunization with myelin antigens. To investigate human immune responses against myelin antigens in vivo we established a new subclinical experimental autoimmune encephalomyelitis model in humanized mice. NOD/Scidγc⁻/⁻ animals were transferred with peripheral blood mononuclear cells from healthy human donors and immunized with myelin antigens in complete Freund's adjuvant and antigen-pulsed autologous dendritic cells. Human T cells recovered from these animals reacted specifically to the soluble domain of myelin oligodendrocyte glycoprotein and secreted proinflammatory cytokines. Furthermore, immunized animals developed subclinical CNS inflammation with infiltrating CD4⁺ and CD8⁺ T cells and production of encephalitogenic cytokines. Thus, this model of myelin-induced CNS inflammation by human T cells may allow testing of new human-specific therapeuticals for multiple sclerosis.

The antiphospholipid syndrome (APS) is an autoimmune disease where the presence of high titers of circulating autoantibodies causes thrombosis with consecutive infarcts. In experimental APS (eAPS), a mouse model of APS, behavioral abnormalities develop in the absence of vessel occlusion or infarcts. Using brain hemispheres of control and eAPS mice with documented neurological and cognitive deficits, we checked for lymphocytic infiltration, activation of glia and macrophages, as well as alterations of ligand binding densities of various neurotransmitter receptors to unravel the molecular basis of this abnormal behavior. Lymphocytic infiltrates were immunohistochemically characterized using antibodies against CD3, CD4, CD8 and forkhead box P3 (Foxp3), respectively. GFAP, Iba1 and CD68-immunohistochemistry was performed, to check for activation of astrocytes, microglia and macrophages. Ligand binding densities of NMDA, AMPA, GABAA and 5-HT1A receptors were analyzed by in vitro receptor autoradiography. No significant inflammatory reaction occurred in eAPS mice. There was neither activation of astrocytes or microglia nor accumulation of macrophages. Binding values of excitatory and inhibitory neurotransmitter receptors were largely unchanged. However, ligand binding densities of the modulatory serotonergic 5-HT1A receptors in the hippocampus and in the primary somatosensory cortex of eAPS mice were significantly upregulated which is suggested to induce the behavioral abnormalities observed.

Background and Purpose— The neuroprotective potential of citicoline in acute ischemic stroke has been shown in many experimental studies and, although the exact mechanisms are still unknown, a clinical Phase III trial is currently underway. Our present study was designed to check whether citicoline also enhances neuroregeneration after experimental stroke. Methods— Forty Wistar rats were subjected to photothrombotic stroke and treated either with daily injections of citicoline (100 mg/kg) or vehicle for 10 consecutive days starting 24 hours after ischemia induction. Sensorimotor tests were performed after an adequate training period at Days 1, 10, 21, and 28 after stroke. Then brains were removed and analyzed for infarct size, glial scar formation, neurogenesis, and ligand binding densities of excitatory and inhibitory neurotransmitter receptors. Results— Animals treated with citicoline showed a significantly better neurological outcome at Days 10, 21, and 28 after ischemia, which could not be attributed to differences in infarct volumes or glial scar formation. However, neurogenesis in the dentate gyrus, subventricular zone, and peri-infarct area was significantly increased by citicoline. Furthermore, enhanced neurological outcome after citicoline treatment was associated with a shift toward excitation in the perilesional cortex. Conclusions— Our present data demonstrate that, apart from the well-known neuroprotective effects in acute ischemic stroke, citicoline also possesses a substantial neuroregenerative potential. Thanks to its multimodal effects, easy applicability, and history as a well-tolerated drug, promising possibilities of neurological treatment including chronic stroke open up.

Using a transgenic mouse model of ischemic stroke we checked for a possible interaction of antiphospholipid antibodies (aPL) which often cause thromboses as well as central nervous system (CNS) involvement under non-thrombotic conditions and the TWEAK/Fn14 pathway known to be adversely involved in inflammatory and ischemic brain disease. After 7 days, infarct volumes were reduced in Fn14 deficient mice and were further decreased by aPL treatment. This was associated with strongest increase of the endogenous neuroprotective G-CSF/G-CSF receptor system. This unexpected beneficial action of aPL is an example for a non-thrombogenic action and the double-edged nature of aPL.

It has been shown that stimulation of endothelial cells and monocytes by antiphospholipid antibodies leads to a prothrombotic state involving upregulation of tissue factor (TF). We examined the in vitro effects of IgG fractions from patients with antiphospholipid syndrome (APS) and of a β-2-glycoprotein 1-independent human monoclonal antiphospholipid antibody (HL-5B) on human umbilical vein endothelial cells (HUVEC) in comparison to untreated cell controls and to exposure to monoclonal IgG control antibody. We also examined the effect of recombinant monocyte chemoattractant protein-1 (MCP-1) on peripheral blood monocytes. Stimulation of endothelial cells with APS IgG fractions or HL-5B resulted in time-dependent upregulation of MCP-1 mRNA and protein expression. Stimulation with HL-5B also led to time-dependent upregulation of interleukin (IL)-8 and intracellular adhesion molecule-1 (ICAM-1) mRNA and IL-8 protein expressions. Stimulation of monocytes with recombinant MCP-1 resulted in an upregulation of TF mRNA and TF protein. In conclusion these results might represent a mechanism for antiphospholipid antibody-mediated thrombosis in APS patients.

Recently, we could demonstrate in rats that a short transient oligemic period of only 20-minute duration, induced by systemic hypotension, resulted in a transient decline of spatial memory capacities without any histological damage over a subsequent period of 6 months. In our present study, we checked for more subtle alterations within the highly vulnerable hippocampal CA1 subfield using quantification of neuronal cell density and semi-quantitative analysis of the ischemia-sensitive protein MAP2. Since hippocampal excitatory and inhibitory neurotransmitter receptors are crucially involved in spatial memory processes, quantitative in vitro receptor autoradiography was performed using [(3)H]MK-801, [(3)H]AMPA, and [(3)H]muscimol for labeling of NMDA, AMPA, and GABA(A) receptors, respectively. Ligand binding values were analyzed in the ischemia-sensitive hippocampal formation and in the parietal cortex. Transient oligemia did not cause any reduction of the neuronal cell density in the vulnerable CA1 subfield nor did it cause any significant changes of MAP2 protein expression in the dendritic layers of CA1. After oligemia, hippocampal binding densities of NMDA, AMPA, and GABA(A) receptors remained unchanged in all subfields investigated. Similarly, there was no difference in cortical ligand binding values of the excitatory NMDA and AMPA receptors comparing oligemic to sham-operated control rats. In the parietal cortex, however, transient oligemia caused a significant reduction of [(3)H]muscimol binding values compared to controls. These findings demonstrate long-term changes in receptor binding densities even after short oligemic periods possibly reflecting part of the molecular basis leading to impaired cognitive abilities.

Changes in DNA methylation patterns during embryo development and differentiation processes are linked to the transcriptional plasticity of our genome. However, little is known about the evolutionary conservation of DNA methylation patterns and the evolutionary impact of epigenetic differences between closely related species. Here we compared the methylation patterns of CpG islands (CGIs) in the promoter regions of seven genes in humans and chimpanzees. We identified a block of CpGs in the cell cycle-related kinase (CCRK) gene that is more methylated in the adult human cortex than in the chimpanzee cortex and, in addition, it exhibits considerable intraspecific variation both in humans and chimpanzees. The species-specifically methylated region (SMR) lies between the almost completely methylated 5' region and the completely demethylated 3' region of the presumed CCRK CGI promoter. It is part of an Alu-Sg1 repeat that has been integrated into the promoter region in a common ancestor of humans and New World monkeys. This SMR is relatively hypomethylated in the rhesus monkey cortex and more or less completely methylated in the baboon cortex, indicating extraordinary methylation dynamics during primate evolution. The mRNA expression level of CCRK has also changed during the course of primate evolution. CCRK is expressed at much higher levels in human and baboon cortices, which display an average SMR methylation of 70% and 100%, respectively, than in chimpanzee and rhesus macaque cortices with an average SMR methylation of 35% and 40%, respectively. The observed evolutionary dynamics suggests a possibility that CCRK has been important for evolution of the primate brain.

The antiphospholipid syndrome (APS) is an autoimmune disease characterized by high titres of auto-antibodies (aPL) leading to thrombosis and consequent infarcts. However, many affected patients develop neurological symptoms in the absence of stroke. Similarly, in a mouse model of this disease (eAPS), animals consistently develop behavioural abnormalities despite lack of ischemic brain injury. Therefore, the present study was designed to identify structural alterations of hippocampal neurones underlying the neurological symptoms in eAPS.Adult female Balb/C mice were subjected to either induction of eAPS by immunization with β2-Glycoprotein 1 or to a control group. After sixteen weeks animals underwent behavioural and cognitive testing using Staircase test (experiment 1 and 2) and Y-maze alternation test (experiment 1) and were tested for serum aPL levels (both experiments). Animals of experiment 1 (n = 7/group) were used for hippocampal neurone analysis using Golgi-Cox staining. Animals of experiment 2 (n = 7/group) were used to analyse molecular markers of total dendritic integrity (MAP2), presynaptic plasticity (synaptobrevin 2/VAMP2) and dendritic spines (synaptopodin) using immunohistochemistry.eAPS mice developed increased aPL titres and presented with abnormal behaviour and impaired short term memory. Further, they revealed a reduction of dendritic complexity of hippocampal CA1 neurones as reflected by decreased dendritic length, arborization and spine density, respectively. Additional decrease of the spine-associated protein expression of Synaptopodin points to dendritic spines as major targets in the pathological process.Reduction of hippocampal dendritic complexity may represent the structural basis for the behavioural and cognitive abnormalities of eAPS mice.