Publications by authors named "Jochen Herms"

147 Publications

Correction to: Mutations within FGFR1 are associated with superior outcome in a series of 83 diffuse midline gliomas with H3F3A K27M mutations.

Acta Neuropathol 2021 Feb 9. Epub 2021 Feb 9.

Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.

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http://dx.doi.org/10.1007/s00401-021-02273-8DOI Listing
February 2021

Mutations within FGFR1 are associated with superior outcome in a series of 83 diffuse midline gliomas with H3F3A K27M mutations.

Acta Neuropathol 2021 02 12;141(2):323-325. Epub 2021 Jan 12.

Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.

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http://dx.doi.org/10.1007/s00401-020-02259-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7847449PMC
February 2021

Microglial activation in the right amygdala-entorhinal-hippocampal complex is associated with preserved spatial learning in App mice.

Neuroimage 2020 Dec 29;230:117707. Epub 2020 Dec 29.

Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany; Munich Cluster for Systems Neurology (SyNergy), Munich, Germany. Electronic address:

Background: In Alzheimer`s disease (AD), regional heterogeneity of β-amyloid burden and microglial activation of individual patients is a well-known phenomenon. Recently, we described a high incidence of inter-individual regional heterogeneity in terms of asymmetry of plaque burden and microglial activation in β-amyloid mouse models of AD as assessed by positron-emission-tomography (PET). We now investigate the regional associations between amyloid plaque burden, microglial activation, and impaired spatial learning performance in transgenic mice in vivo.

Methods: In 30 App mice (15 female, 15 male) we acquired cross-sectional 18 kDa translocator protein (TSPO-PET, F-GE-180) and β-amyloid-PET (F-florbetaben) scans at ten months of age. Control data were obtained from age- and sex-matched C57BI/6 wild-type mice. We assessed spatial learning (i.e. Morris water maze) within two weeks of PET scanning and correlated the principal component of spatial learning performance scores with voxel-wise β-amyloid and TSPO tracer uptake maps in App mice, controlled for age and sex. In order to assess the effects of hemispheric asymmetry, we also analyzed correlations of spatial learning performance with tracer uptake in bilateral regions of interest for frontal cortex, entorhinal/piriform cortex, amygdala, and hippocampus, using a regression model. We tested the correlation between regional asymmetry of PET biomarkers with individual spatial learning performance.

Results: Voxel-wise analyses in App mice revealed that higher TSPO-PET signal in the amygdala, entorhinal and piriform cortices, the hippocampus and the hypothalamus correlated with spatial learning performance. Region-based analysis showed significant correlations between TSPO expression in the right entorhinal/piriform cortex and the right amygdala and spatial learning performance, whereas there were no such correlations in the left hemisphere. Right lateralized TSPO expression in the amygdala predicted better performance in the Morris water maze (β = -0.470, p = 0.013), irrespective of the global microglial activation and amyloid level. Region-based results for amyloid-PET showed no significant associations with spatial learning.

Conclusion: Elevated microglial activation in the right amygdala-entorhinal-hippocampal complex of App mice is associated with better spatial learning. Our findings support a protective role of microglia on cognitive function when they highly express TSPO in specific brain regions involved in spatial memory.
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http://dx.doi.org/10.1016/j.neuroimage.2020.117707DOI Listing
December 2020

Glial activation is moderated by sex in response to amyloidosis but not to tau pathology in mouse models of neurodegenerative diseases.

J Neuroinflammation 2020 Dec 14;17(1):374. Epub 2020 Dec 14.

Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Marchioninstraße 15, 81377, Munich, Germany.

Background: In vivo assessment of neuroinflammation by 18-kDa translocator protein positron-emission-tomography (TSPO-PET) ligands receives growing interest in preclinical and clinical research of neurodegenerative disorders. Higher TSPO-PET binding as a surrogate for microglial activation in females has been reported for cognitively normal humans, but such effects have not yet been evaluated in rodent models of neurodegeneration and their controls. Thus, we aimed to investigate the impact of sex on microglial activation in amyloid and tau mouse models and wild-type controls.

Methods: TSPO-PET (F-GE-180) data of C57Bl/6 (wild-type), App (β-amyloid model), and P301S (tau model) mice was assessed longitudinally between 2 and 12 months of age. The App group also underwent longitudinal β-amyloid-PET imaging (Aβ-PET; F-florbetaben). PET results were confirmed and validated by immunohistochemical investigation of microglial (Iba-1, CD68), astrocytic (GFAP), and tau (AT8) markers. Findings in cerebral cortex were compared by sex using linear mixed models for PET data and analysis of variance for immunohistochemistry.

Results: Wild-type mice showed an increased TSPO-PET signal over time (female +23%, male +4%), with a significant sex × age interaction (T = - 4.171, p < 0.001). The Aβ model App mice also showed a significant sex × age interaction (T = - 2.953, p = 0.0048), where cortical TSPO-PET values increased by 31% in female App mice, versus only 6% in the male mice group from 2.5 to 10 months of age. Immunohistochemistry for the microglial markers Iba-1 and CD68 confirmed the TSPO-PET findings in male and female mice aged 10 months. Aβ-PET in the same App mice indicated no significant sex × age interaction (T = 0.425, p = 0.673). The P301S tau model showed strong cortical increases of TSPO-PET from 2 to 8.5 months of age (female + 32%, male + 36%), without any significant sex × age interaction (T = - 0.671, p = 0.504), and no sex differences in Iba-1, CD68, or AT8 immunohistochemistry.

Conclusion: Female mice indicate sex-dependent microglia activation in aging and in response to amyloidosis but not in response to tau pathology. This calls for consideration of sex difference in TSPO-PET studies of microglial activation in mouse models of neurodegeneration and by extension in human studies.
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http://dx.doi.org/10.1186/s12974-020-02046-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7737385PMC
December 2020

Improved risk stratification in younger wild-type glioblastoma patients by combining a 4-miRNA signature with promoter methylation status.

Neurooncol Adv 2020 Jan-Dec;2(1):vdaa137. Epub 2020 Oct 15.

Department of Radiation Oncology, University Hospital, LMU Munich, Munich, Germany.

Background: The potential benefit of risk stratification using a 4-miRNA signature in combination with promoter methylation in wild-type glioblastoma patients was assessed.

Methods: Primary tumors from 102 patients with comparable treatment from the LMU Munich ( = 37), the University Hospital Düsseldorf ( = 33), and The Cancer Genome Atlas ( = 32) were included. Risk groups were built using expressions of hsa-let-7a-5p, hsa-let-7b-5p, hsa-miR-615-5p, and hsa-miR-125a-5p to assess prognostic performance in overall survival (OS). promoter methylation and age were considered as cofactors. Integrated miRNA, DNA methylome, and transcriptome analysis were used to explore the functional impact of signature miRNAs.

Results: The 4-miRNA signature defined high-risk ( = 46, median OS: 15.8 months) and low-risk patients ( = 56, median OS: 20.7 months; univariable Cox proportional hazard analysis: hazard ratio [HR]: 1.8, 95% confidence interval [CI]: 1.14-2.83, = .01). The multivariable Cox proportional hazard model including the 4-miRNA signature ( = .161), promoter methylation ( < .001), and age ( = .034) significantly predicted OS (Log-rank < .0001). Likewise to clinical routine, analysis was performed for younger (≤60 years, = 50, median OS: 20.2 months) and older patients (>60 years, = 52, median OS: 15.8) separately. In younger patients, the 4-miRNA signature had prognostic value (HR: 1.92, 95% CI: 0.93-3.93, = .076). Particularly, younger, methylated, 4-miRNA signature low-risk patients ( = 18, median OS: 37.4 months) showed significantly improved survival, compared to other younger patients ( = 32, OS 18.5 months; HR: 0.33, 95% CI: 0.15-0.71, = .003). Integrated data analysis revealed 4-miRNA signature-associated genes and pathways.

Conclusion: The prognostic 4-miRNA signature in combination with promoter methylation improved risk stratification with the potential for therapeutic substratification, especially of younger patients.
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http://dx.doi.org/10.1093/noajnl/vdaa137DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7712804PMC
October 2020

In Vivo Assessment of Neuroinflammation in 4-Repeat Tauopathies.

Mov Disord 2020 Nov 27. Epub 2020 Nov 27.

Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich, Germany.

Background: Neuroinflammation has received growing interest as a therapeutic target in neurodegenerative disorders, including 4-repeat tauopathies.

Objectives: The aim of this cross-sectional study was to investigate 18 kDa translocator protein positron emission tomography (PET) as a biomarker for microglial activation in the 4-repeat tauopathies corticobasal degeneration and progressive supranuclear palsy.

Methods: Specific binding of the 18 kDa translocator protein tracer F-GE-180 was determined by serial PET during pharmacological depletion of microglia in a 4-repeat tau mouse model. The 18 kDa translocator protein PET was performed in 30 patients with corticobasal syndrome (68 ± 9 years, 16 women) and 14 patients with progressive supranuclear palsy (69 ± 9 years, 8 women), and 13 control subjects (70 ± 7 years, 7 women). Group comparisons and associations with parameters of disease progression were assessed by region-based and voxel-wise analyses.

Results: Tracer binding was significantly reduced after pharmacological depletion of microglia in 4-repeat tau mice. Elevated 18 kDa translocator protein labeling was observed in the subcortical brain areas of patients with corticobasal syndrome and progressive supranuclear palsy when compared with controls and was most pronounced in the globus pallidus internus, whereas only patients with corticobasal syndrome showed additionally elevated tracer binding in motor and supplemental motor areas. The 18 kDa translocator protein labeling was not correlated with parameters of disease progression in corticobasal syndrome and progressive supranuclear palsy but allowed sensitive detection in patients with 4-repeat tauopathies by a multiregion classifier.

Conclusions: Our data indicate that F-GE-180 PET detects microglial activation in the brain of patients with 4-repeat tauopathy, fitting to predilection sites of the phenotype. The 18 kDa translocator protein PET has a potential for monitoring neuroinflammation in 4-repeat tauopathies. © 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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http://dx.doi.org/10.1002/mds.28395DOI Listing
November 2020

Extent and prognostic value of MGMT promotor methylation in glioma WHO grade II.

Sci Rep 2020 11 12;10(1):19758. Epub 2020 Nov 12.

Division of Neuro-Oncology, Department of Neurosurgery, Ludwig Maximilians University School of Medicine, Marchioninistrasse 15, 81377, Munich, Germany.

MGMT promotor methylation is associated with favourable outcome in high-grade glioma. In glioma WHO grade II, it is unclear whether the extent of MGMT promotor methylation and its prognostic role is independent from other molecular markers. We performed a retrospective analysis of 155 patients with glioma WHO grade II. First, all 155 patients were assigned to three molecular groups according to the 2016 WHO classification system: (1) oligodendroglioma, IDH-mutant and 1p19q co-deleted (n = 81); (2) astrocytoma, IDH-mutant and 1p19q non-codeleted (n = 54); (3) astrocytoma, IDH-wildtype (n = 20). MGMT promotor methylation was quantified using Sanger sequencing of the CpG sites 74-98 within the MGMT promotor region. Highest numbers of methylated CpG sites were found for oligodendroglioma, IDH-mutant and 1p19q co-deleted. When 1p19q co-deletion was absent, numbers of methylated CpG sites were higher in the presence of IDH-mutation. Accordingly, lowest numbers were seen in the IDH-wildtype subpopulation. In the entire cohort, larger numbers of methylated CpG sites were associated with favourable outcome. When analysed separately for the three WHO subgroups, a similar association was only retained in astrocytoma, IDH-wildtype. Collectively, extent of MGMT promotor methylation was strongly associated with other molecular markers and added prognostic information in astrocytoma, IDH-wildtype. Evaluation in prospective cohorts is warranted.
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http://dx.doi.org/10.1038/s41598-020-76312-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7661705PMC
November 2020

Assessment of 18F-PI-2620 as a Biomarker in Progressive Supranuclear Palsy.

JAMA Neurol 2020 Nov;77(11):1408-1419

Department of Nuclear Medicine, University of Leipzig, Leipzig, Germany.

Importance: Progressive supranuclear palsy (PSP) is a 4-repeat tauopathy. Region-specific tau aggregates establish the neuropathologic diagnosis of definite PSP post mortem. Future interventional trials against tau in PSP would strongly benefit from biomarkers that support diagnosis.

Objective: To investigate the potential of the novel tau radiotracer 18F-PI-2620 as a biomarker in patients with clinically diagnosed PSP.

Design, Setting, And Participants: In this cross-sectional study, participants underwent dynamic 18F-PI-2620 positron emission tomography (PET) from 0 to 60 minutes after injection at 5 different centers (3 in Germany, 1 in the US, and 1 in Australia). Patients with PSP (including those with Richardson syndrome [RS]) according to Movement Disorder Society PSP criteria were examined together with healthy controls and controls with disease. Four additionally referred individuals with PSP-RS and 2 with PSP-non-RS were excluded from final data analysis owing to incomplete dynamic PET scans. Data were collected from December 2016 to October 2019 and were analyzed from December 2018 to December 2019.

Main Outcomes And Measures: Postmortem autoradiography was performed in independent PSP-RS and healthy control samples. By in vivo PET imaging, 18F-PI-2620 distribution volume ratios were obtained in globus pallidus internus and externus, putamen, subthalamic nucleus, substantia nigra, dorsal midbrain, dentate nucleus, dorsolateral, and medial prefrontal cortex. PET data were compared between patients with PSP and control groups and were corrected for center, age, and sex.

Results: Of 60 patients with PSP, 40 (66.7%) had RS (22 men [55.0%]; mean [SD] age, 71 [6] years; mean [SD] PSP rating scale score, 38 [15]; score range, 13-71) and 20 (33.3%) had PSP-non-RS (11 men [55.0%]; mean [SD] age, 71 [9] years; mean [SD] PSP rating scale score, 24 [11]; score range, 11-41). Ten healthy controls (2 men; mean [SD] age, 67 [7] years) and 20 controls with disease (of 10 [50.0%] with Parkinson disease and multiple system atrophy, 7 were men; mean [SD] age, 61 [8] years; of 10 [50.0%] with Alzheimer disease, 5 were men; mean [SD] age, 69 [10] years). Postmortem autoradiography showed blockable 18F-PI-2620 binding in patients with PSP and no binding in healthy controls. The in vivo findings from the first large-scale observational study in PSP with 18F-PI-2620 indicated significant elevation of tracer binding in PSP target regions with strongest differences in PSP vs control groups in the globus pallidus internus (mean [SD] distribution volume ratios: PSP-RS, 1.21 [0.10]; PSP-non-RS, 1.12 [0.11]; healthy controls, 1.00 [0.08]; Parkinson disease/multiple system atrophy, 1.03 [0.05]; Alzheimer disease, 1.08 [0.06]). Sensitivity and specificity for detection of PSP-RS vs any control group were 85% and 77%, respectively, when using classification by at least 1 positive target region.

Conclusions And Relevance: This multicenter evaluation indicates a value of 18F-PI-2620 to differentiate suspected patients with PSP, potentially facilitating more reliable diagnosis of PSP.
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http://dx.doi.org/10.1001/jamaneurol.2020.2526DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7341407PMC
November 2020

Contribution of the astrocytic tau pathology to synapse loss in progressive supranuclear palsy and corticobasal degeneration.

Brain Pathol 2020 Oct 22:e12914. Epub 2020 Oct 22.

German Center for Neurodegenerative Diseases (DZNE) e.V., Site Munich, Munich, Germany.

Primary 4-repeat tauopathies with frontotemporal lobar degeneration (FTLD) like Progressive Supranuclear Palsy (PSP) or Corticobasal Degeneration (CBD) show diverse cellular pathology in various brain regions. Besides shared characteristics of neuronal and oligodendroglial cytoplasmic inclusions of accumulated hyperphosphorylated tau protein (pTau), astrocytes in PSP and CBD contain pathognomonic pTau aggregates - hence, lending the designation tufted astrocytes (TA) or astrocytic plaques (AP), respectively. pTau toxicity is most commonly assigned to neurons, whereas the implications of astrocytic pTau for maintaining neurotransmission within the tripartite synapse of human brains is not well understood. We performed immunofluorescent synapse labeling and automated puncta quantification in the medial frontal gyrus (MFG) and striatal regions from PSP and CBD postmortem samples to capture morphometric synaptic alterations. This approach indicated general synaptic losses of both, excitatory and inhibitory bipartite synapses in the frontal cortex of PSP cases, whereas in CBD lower synapse densities were only related to astrocytic plaques. In contrast to tufted astrocytes in PSP, affected astrocytes in CBD could not preserve synaptic integrity within their spatial domains, when compared to non-affected internal astrocytes or astrocytes in healthy controls. These findings suggest a pTau pathology-associated role of astrocytes in maintaining connections within neuronal circuits, considered as the microscopic substrate of cognitive dysfunction in CBD. By contrasting astrocytic-synaptic associations in both diseases, we hereby highlight astrocytic pTau as an important subject of prospective research and as a potential cellular target for therapeutic approaches in the primary tauopathies PSP and CBD.
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http://dx.doi.org/10.1111/bpa.12914DOI Listing
October 2020

Dual PET Imaging of an H3K27M-Mutant Glioma With 18F-GE-180 and 18F-FET PET.

Clin Nucl Med 2020 Dec;45(12):992-993

Neuropathology.

A 25-year-old man presented with headache and intracranial pressure symptoms. On MRI, an intracranial lesion was detected in the right thalamus with exophytic growth into the third ventricle and inhomogeneous contrast enhancement without necrosis. Dual amino acid (F-FET) and TSPO (F-GE-180) PET imaging showed high tumor-to-background ratios in both scans and a short time-to-peak in F-FET uptake dynamics. Biopsy revealed a diffuse midline glioma, H3K27M-mutant (WHO grade IV), a novel entity in the 2016 WHO classification with poor clinical outcome. Our case shows that the highly aggressive features of this tumor entity can be visualized in vivo by both PET modalities.
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http://dx.doi.org/10.1097/RLU.0000000000003331DOI Listing
December 2020

Higher CSF sTREM2 and microglia activation are associated with slower rates of beta-amyloid accumulation.

EMBO Mol Med 2020 09 10;12(9):e12308. Epub 2020 Aug 10.

Institute for Stroke and Dementia Research (ISD), University Hospital, Ludwig Maximilian University (LMU), Munich, Germany.

Microglia activation is the brain's major immune response to amyloid plaques in Alzheimer's disease (AD). Both cerebrospinal fluid (CSF) levels of soluble TREM2 (sTREM2), a biomarker of microglia activation, and microglia PET are increased in AD; however, whether an increase in these biomarkers is associated with reduced amyloid-beta (Aβ) accumulation remains unclear. To address this question, we pursued a two-pronged translational approach. Firstly, in non-demented and demented individuals, we tested CSF sTREM2 at baseline to predict (i) amyloid PET changes over ∼2 years and (ii) tau PET cross-sectionally assessed in a subset of patients. We found higher CSF sTREM2 associated with attenuated amyloid PET increase and lower tau PET. Secondly, in the App mouse model of amyloidosis, we studied baseline F-GE180 microglia PET and longitudinal amyloid PET to test the microglia vs. Aβ association, without any confounding co-pathologies often present in AD patients. Higher microglia PET at age 5 months was associated with a slower amyloid PET increase between ages 5-to-10 months. In conclusion, higher microglia activation as determined by CSF sTREM2 or microglia PET shows protective effects on subsequent amyloid accumulation.
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http://dx.doi.org/10.15252/emmm.202012308DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7507349PMC
September 2020

Longitudinal TSPO expression in tau transgenic P301S mice predicts increased tau accumulation and deteriorated spatial learning.

J Neuroinflammation 2020 Jul 13;17(1):208. Epub 2020 Jul 13.

Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, 81377, Munich, Germany.

Background: P301S tau transgenic mice show age-dependent accumulation of neurofibrillary tangles in the brainstem, hippocampus, and neocortex, leading to neuronal loss and cognitive deterioration. However, there is hitherto only sparse documentation of the role of neuroinflammation in tau mouse models. Thus, we analyzed longitudinal microglial activation by small animal 18 kDa translocator protein positron-emission-tomography (TSPO μPET) imaging in vivo, in conjunction with terminal assessment of tau pathology, spatial learning, and cerebral glucose metabolism.

Methods: Transgenic P301S (n = 33) and wild-type (n = 18) female mice were imaged by F-GE-180 TSPO μPET at the ages of 1.9, 3.9, and 6.4 months. We conducted behavioral testing in the Morris water maze, F-fluordesoxyglucose (F-FDG) μPET, and AT8 tau immunohistochemistry at 6.3-6.7 months. Terminal microglial immunohistochemistry served for validation of TSPO μPET results in vivo, applying target regions in the brainstem, cortex, cerebellum, and hippocampus. We compared the results with our historical data in amyloid-β mouse models.

Results: TSPO expression in all target regions of P301S mice increased exponentially from 1.9 to 6.4 months, leading to significant differences in the contrasts with wild-type mice at 6.4 months (+ 11-23%, all p < 0.001), but the apparent microgliosis proceeded more slowly than in our experience in amyloid-β mouse models. Spatial learning and glucose metabolism of AT8-positive P301S mice were significantly impaired at 6.3-6.5 months compared to the wild-type group. Longitudinal increases in TSPO expression predicted greater tau accumulation and lesser spatial learning performance at 6.3-6.7 months.

Conclusions: Monitoring of TSPO expression as a surrogate of microglial activation in P301S tau transgenic mice by μPET indicates a delayed time course when compared to amyloid-β mouse models. Detrimental associations of microglial activation with outcome parameters are opposite to earlier data in amyloid-β mouse models. The contribution of microglial response to pathology accompanying amyloid-β and tau over-expression merits further investigation.
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http://dx.doi.org/10.1186/s12974-020-01883-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7358201PMC
July 2020

Fibrillar Aβ triggers microglial proteome alterations and dysfunction in Alzheimer mouse models.

Elife 2020 06 8;9. Epub 2020 Jun 8.

German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.

Microglial dysfunction is a key pathological feature of Alzheimer's disease (AD), but little is known about proteome-wide changes in microglia during the course of AD and their functional consequences. Here, we performed an in-depth and time-resolved proteomic characterization of microglia in two mouse models of amyloid β (Aβ) pathology, the overexpression APPPS1 and the knock-in APP-NL-G-F (APP-KI) model. We identified a large panel of Microglial Aβ Response Proteins (MARPs) that reflect heterogeneity of microglial alterations during early, middle and advanced stages of Aβ deposition and occur earlier in the APPPS1 mice. Strikingly, the kinetic differences in proteomic profiles correlated with the presence of fibrillar Aβ, rather than dystrophic neurites, suggesting that fibrillar Aβ may trigger the AD-associated microglial phenotype and the observed functional decline. The identified microglial proteomic fingerprints of AD provide a valuable resource for functional studies of novel molecular targets and potential biomarkers for monitoring AD progression or therapeutic efficacy.
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http://dx.doi.org/10.7554/eLife.54083DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7279888PMC
June 2020

Asymmetry of Fibrillar Plaque Burden in Amyloid Mouse Models.

J Nucl Med 2020 12 15;61(12):1825-1831. Epub 2020 May 15.

Department of Nuclear Medicine, University Hospital of Munich, Ludwig Maximilian University Munich, Munich, Germany

Asymmetries of amyloid-β (Aβ) burden are well known in Alzheimer disease (AD) but did not receive attention in Aβ mouse models of Alzheimer disease. Therefore, we investigated Aβ asymmetries in Aβ mouse models examined by Aβ small-animal PET and tested if such asymmetries have an association with microglial activation. We analyzed 523 cross-sectional Aβ PET scans of 5 different Aβ mouse models (APP/PS1, PS2APP, APP-SL70, , and APPswe) together with 136 18-kDa translocator protein (TSPO) PET scans for microglial activation. The asymmetry index (AI) was calculated between tracer uptake in both hemispheres. AIs of Aβ PET were analyzed in correlation with TSPO PET AIs. Extrapolated required sample sizes were compared between analyses of single and combined hemispheres. Relevant asymmetries of Aβ deposition were identified in at least 30% of all investigated mice. There was a significant correlation between AIs of Aβ PET and TSPO PET in 4 investigated Aβ mouse models (APP/PS1: = 0.593, = 0.001; PS2APP: = 0.485, = 0.019; APP-SL70: = 0.410, = 0.037; : = 0.385, = 0.002). Asymmetry was associated with higher variance of tracer uptake in single hemispheres, leading to higher required sample sizes. Asymmetry of fibrillar plaque neuropathology occurs frequently in Aβ mouse models and acts as a potential confounder in experimental designs. Concomitant asymmetry of microglial activation indicates a neuroinflammatory component to hemispheric predominance of fibrillary amyloidosis.
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http://dx.doi.org/10.2967/jnumed.120.242750DOI Listing
December 2020

An 8-Year-Old Girl with Posterior Fossa Mass.

Brain Pathol 2020 05;30(3):713-714

Department of Pediatric Hematology and Oncology, University Medical Center Hamburg Eppendorf, Germany.

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http://dx.doi.org/10.1111/bpa.12833DOI Listing
May 2020

Early-phase [F]PI-2620 tau-PET imaging as a surrogate marker of neuronal injury.

Eur J Nucl Med Mol Imaging 2020 11 21;47(12):2911-2922. Epub 2020 Apr 21.

Department of Nuclear Medicine, University Hospital of Munich LMU Munich, Marchioninstraße 15, 81377, Munich, Germany.

Purpose: Second-generation tau radiotracers for use with positron emission tomography (PET) have been developed for visualization of tau deposits in vivo. For several β-amyloid and first-generation tau-PET radiotracers, it has been shown that early-phase images can be used as a surrogate of neuronal injury. Therefore, we investigated the performance of early acquisitions of the novel tau-PET radiotracer [F]PI-2620 as a potential substitute for [F]fluorodeoxyglucose ([F]FDG).

Methods: Twenty-six subjects were referred with suspected tauopathies or overlapping parkinsonian syndromes (Alzheimer's disease, progressive supranuclear palsy, corticobasal syndrome, multi-system atrophy, Parkinson's disease, multi-system atrophy, Parkinson's disease, frontotemporal dementia) and received a dynamic [F]PI-2620 tau-PET (0-60 min p.i.) and static [F]FDG-PET (30-50 min p.i.). Regional standardized uptake value ratios of early-phase images (single frame SUVr) and the blood flow estimate (R) of [F]PI-2620-PET were correlated with corresponding quantification of [F]FDG-PET (global mean/cerebellar normalization). Reduced tracer uptake in cortical target regions was also interpreted visually using 3-dimensional stereotactic surface projections by three more and three less experienced readers. Spearman rank correlation coefficients were calculated between early-phase [F]PI-2620 tau-PET and [F]FDG-PET images for all cortical regions and frequencies of disagreement between images were compared for both more and less experienced readers.

Results: Highest agreement with [F]FDG-PET quantification was reached for [F]PI-2620-PET acquisition from 0.5 to 2.5 min p.i. for global mean (lowest R = 0.69) and cerebellar scaling (lowest R = 0.63). Correlation coefficients (summed 0.5-2.5 min SUVr & R) displayed strong agreement in all cortical target regions for global mean (R 0.76, R = 0.77) and cerebellar normalization (R 0.68, R = 0.68). Visual interpretation revealed high regional correlations between early-phase tau-PET and [F]FDG-PET. There were no relevant differences between more and less experienced readers.

Conclusion: Early-phase imaging of [F]PI-2620 can serve as a surrogate biomarker for neuronal injury. Dynamic imaging or a dual time-point protocol for tau-PET imaging could supersede additional [F]FDG-PET imaging by indexing both the distribution of tau and the extent of neuronal injury.
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http://dx.doi.org/10.1007/s00259-020-04788-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7567714PMC
November 2020

Zoonotic spillover infections with Borna disease virus 1 leading to fatal human encephalitis, 1999-2019: an epidemiological investigation.

Lancet Infect Dis 2020 04 7;20(4):467-477. Epub 2020 Jan 7.

Institute of Clinical Microbiology and Hygiene, Regensburg University Hospital, Regensburg, Germany.

Background: In 2018-19, Borna disease virus 1 (BoDV-1), the causative agent of Borna disease in horses, sheep, and other domestic mammals, was reported in five human patients with severe to fatal encephalitis in Germany. However, information on case frequencies, clinical courses, and detailed epidemiological analyses are still lacking. We report the occurrence of BoDV-1-associated encephalitis in cases submitted to the Institute of Clinical Microbiology and Hygiene, Regensburg University Hospital, Regensburg, Germany, and provide a detailed description of newly identified cases of BoDV-1-induced encephalitis.

Methods: All brain tissues from 56 encephalitis cases from Bavaria, Germany, of putative viral origin (1999-2019), which had been submitted for virological testing upon request of the attending clinician and stored for stepwise diagnostic procedure, were systematically screened for BoDV-1 RNA. Two additional BoDV-1-positive cases were contributed by other diagnostic centres. Positive results were confirmed by deep sequencing, antigen detection, and determination of BoDV-1-reactive antibodies in serum and cerebrospinal fluid. Clinical and epidemiological data from infected patients were collected and analysed.

Findings: BoDV-1 RNA and bornavirus-reactive antibodies were detected in eight newly analysed encephalitis cases and the first human BoDV-1 isolate was obtained from an unequivocally confirmed human BoDV-1 infection from the endemic area. Six of the eight BoDV-1-positive patients had no record of immunosuppression before the onset of fatal disease, whereas two were immunocompromised after solid organ transplantation. Typical initial symptoms were headache, fever, and confusion, followed by various neurological signs, deep coma, and severe brainstem involvement. Seven of nine patients with fatal encephalitis of unclear cause were BoDV-1 positive within one diagnostic centre. BoDV-1 sequence information and epidemiological analyses indicated independent spillover transmissions most likely from the local wild animal reservoir.

Interpretation: BoDV-1 infection has to be considered as a potentially lethal zoonosis in endemic regions with reported spillover infections in horses and sheep. BoDV-1 infection can result in fatal encephalitis in immunocompromised and apparently healthy people. Consequently, all severe encephalitis cases of unclear cause should be tested for bornaviruses especially in endemic regions.

Funding: German Federal Ministry of Education and Research.
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http://dx.doi.org/10.1016/S1473-3099(19)30546-8DOI Listing
April 2020

Loss of fragile X mental retardation protein precedes Lewy pathology in Parkinson's disease.

Acta Neuropathol 2020 02 25;139(2):319-345. Epub 2019 Nov 25.

Department of Translational Neurodegeneration, German Centre for Neurodegenerative Diseases (DZNE), Munich, Germany.

Parkinson's disease (PD) is the most common neurodegenerative movement disorder and is characterized by the progressive loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNc) and the gradual appearance of α-synuclein (α-syn)-containing neuronal protein aggregates. Although the exact mechanism of α-syn-mediated cell death remains elusive, recent research suggests that α-syn-induced alterations in neuronal excitability contribute to cell death in PD. Because the fragile X mental retardation protein (FMRP) controls the expression and function of numerous neuronal genes related to neuronal excitability and synaptic function, we here investigated the role of FMRP in α-syn-associated pathological changes in cell culture and mouse models of PD as well as in post-mortem human brain tissue from PD patients. We found FMRP to be decreased in cultured DA neurons and in the mouse brain in response to α-syn overexpression. FMRP was, furthermore, lost in the SNc of PD patients and in patients with early stages of incidental Lewy body disease (iLBD). Unlike fragile X syndrome (FXS), FMR1 expression in response to α-syn was regulated by a mechanism involving Protein Kinase C (PKC) and cAMP response element-binding protein (CREB). Reminiscent of FXS neurons, α-syn-overexpressing cells exhibited an increase in membrane N-type calcium channels, increased phosphorylation of ERK1/2, eIF4E and S6, increased overall protein synthesis, and increased expression of Matrix Metalloproteinase 9 (MMP9). FMRP affected neuronal function in a PD animal model, because FMRP-KO mice were resistant to the effect of α-syn on striatal dopamine release. In summary, our results thus reveal a new role of FMRP in PD and support the examination of FMRP-regulated genes in PD disease progression.
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http://dx.doi.org/10.1007/s00401-019-02099-5DOI Listing
February 2020

Tau deletion reduces plaque-associated BACE1 accumulation and decelerates plaque formation in a mouse model of Alzheimer's disease.

EMBO J 2019 12 7;38(23):e102345. Epub 2019 Nov 7.

German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.

In Alzheimer's disease, BACE1 protease initiates the amyloidogenic processing of amyloid precursor protein (APP) that eventually results in synthesis of β-amyloid (Aβ) peptide. Aβ deposition in turn causes accumulation of BACE1 in plaque-associated dystrophic neurites, thereby potentiating progressive Aβ deposition once initiated. Since systemic pharmacological BACE inhibition causes adverse effects in humans, it is important to identify strategies that specifically normalize overt BACE1 activity around plaques. The microtubule-associated protein tau regulates axonal transport of proteins, and tau deletion rescues Aβ-induced transport deficits in vitro. In the current study, long-term in vivo two-photon microscopy and immunohistochemistry were performed in tau-deficient APPPS1 mice. Tau deletion reduced plaque-associated axonal pathology and BACE1 accumulation without affecting physiological BACE1 expression distant from plaques. Thereby, tau deletion effectively decelerated formation of new plaques and reduced plaque compactness. The data revealed that tau reinforces Aβ deposition, presumably by contributing to accumulation of BACE1 in plaque-associated dystrophies. Targeting tau-dependent mechanisms could become a suitable strategy to specifically reduce overt BACE1 activity around plaques, thereby avoiding adverse effects of systemic BACE inhibition.
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http://dx.doi.org/10.15252/embj.2019102345DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6885735PMC
December 2019

Identification of Distant Metastases From Recurrent Gliosarcoma Using Whole-Body 18F-FDG PET/CT.

Clin Nucl Med 2019 Nov;44(11):923-924

From the Department of Nuclear Medicine, University Hospital, LMU Munich, Munich.

A 51-year-old man presented with recurrent gliosarcoma and increasing cough over the last months. On F-FDG PET/CT, solid lung masses with high F-FDG uptake were present. A biopsy taken from a lung lesion indicated distant metastases from gliosarcoma. Gliosarcoma, a rare malignant central nervous system tumor, presents with extracranial metastases in only less than 10%. As highlighted by this case, F-FDG PET/CT can be used for whole-body staging in patients with metastatic brain tumor. Vice versa, highly F-FDG-avid lung lesions in patients with brain tumors should lead to distant metastases as differential diagnosis despite their rare occurrence.
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http://dx.doi.org/10.1097/RLU.0000000000002790DOI Listing
November 2019

Early defects in translation elongation factor 1α levels at excitatory synapses in α-synucleinopathy.

Acta Neuropathol 2019 12 26;138(6):971-986. Epub 2019 Aug 26.

Center for Neuropathology and Prion Research, Ludwig-Maximilians University, Munich, Germany.

Cognitive decline and dementia in neurodegenerative diseases are associated with synapse dysfunction and loss, which may precede neuron loss by several years. While misfolded and aggregated α-synuclein is recognized in the disease progression of synucleinopathies, the nature of glutamatergic synapse dysfunction and loss remains incompletely understood. Using fluorescence-activated synaptosome sorting (FASS), we enriched excitatory glutamatergic synaptosomes from mice overexpressing human alpha-synuclein (h-αS) and wild-type littermates to unprecedented purity. Subsequent label-free proteomic quantification revealed a set of proteins differentially expressed upon human alpha-synuclein overexpression. These include overrepresented proteins involved in the synaptic vesicle cycle, ER-Golgi trafficking, metabolism and cytoskeleton. Unexpectedly, we found and validated a steep reduction of eukaryotic translation elongation factor 1 alpha (eEF1A1) levels in excitatory synapses at early stages of h-αS mouse model pathology. While eEF1A1 reduction correlated with the loss of postsynapses, its immunoreactivity was found on both sides of excitatory synapses. Moreover, we observed a reduction in eEF1A1 immunoreactivity in the cingulate gyrus neuropil of patients with Lewy body disease along with a reduction in PSD95 levels. Altogether, our results suggest a link between structural impairments underlying cognitive decline in neurodegenerative disorders and local synaptic defects. eEF1A1 may therefore represent a limiting factor to synapse maintenance.
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http://dx.doi.org/10.1007/s00401-019-02063-3DOI Listing
December 2019

Non-invasive prediction of IDH-wildtype genotype in gliomas using dynamic F-FET PET.

Eur J Nucl Med Mol Imaging 2019 Nov 13;46(12):2581-2589. Epub 2019 Aug 13.

Department of Nuclear Medicine, University Hospital, Ludwig Maximilians-University Munich, Munich, Germany.

Purpose: According to the updated WHO classification of gliomas with its emphasis on molecular parameters, tumours with an IDH-wildtype status have a dismal prognosis. To ensure timely adjustment of treatment, demand for non-invasive prediction methods is high. F-FET PET has been shown to be an important diagnostic tool for glioma management. The aim of this study was to assess the value of dynamic F-FET PET for the non-invasive prediction of the IDH-mutation status.

Methods: Newly diagnosed WHO grade II-IV glioma patients with MRI and dynamic F-FET PET were included. The F-FET PET parameters mean and maximal tumour-to-background ratio (TBR, TBR) and minimal time-to-peak (TTP) were evaluated. The diagnostic power for the prediction of the IDH genotype (positive/negative predictive value) was tested in the overall study group and in the subgroup of non-contrast enhancing gliomas.

Results: Three hundred forty-one patients were evaluated. Molecular analyses revealed 178 IDH-mutant and 163 IDH-wildtype tumours. Overall, 270/341 gliomas were classified as F-FET-positive (TBR > 1.6), 90.2% of the IDH-wildtype and 69.1% of IDH-mutant gliomas. Median TBR was significantly higher in IDH-wildtype compared with IDH-mutant gliomas (2.9 vs. 2.3, p < 0.001); however, ROC-analyses revealed no reliable cutoff due to a high overlap (range 1.0-7.1 vs. 1.1-7.9). Dynamic analysis revealed a significantly shorter TTP in IDH-wildtype gliomas; using TTP ≤ 12.5 min as indicator for IDH-wildtype gliomas, a positive predictive value of 87% was reached (negative predictive value 72%, AUC = 0.796, p ≤ 0.001). A total of 161/341 gliomas did not show contrast enhancement on MRI; even within this subgroup, TTP ≤ 12.5 min remained a good predictor of IDH-wildtype glioma (positive predictive value 83%, negative predictive value 90%; AUC = 0.868, p < 0.001).

Conclusion: A short TTP in dynamic F-FET PET serves as good predictor of highly aggressive IDH-wildtype status in gliomas. In particular, a high diagnostic power was observed in the subgroup of non-contrast enhancing gliomas, which helps to identify patients with worse prognosis.
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http://dx.doi.org/10.1007/s00259-019-04477-3DOI Listing
November 2019

Late-stage Anle138b treatment ameliorates tau pathology and metabolic decline in a mouse model of human Alzheimer's disease tau.

Alzheimers Res Ther 2019 08 1;11(1):67. Epub 2019 Aug 1.

Department of Nuclear Medicine, University Hospital, LMU Munich, Marchioninistr.15, 81377, Munich, Germany.

Background: Augmenting the brain clearance of toxic oligomers with small molecule modulators constitutes a promising therapeutic concept against tau deposition. However, there has been no test of this concept in animal models of Alzheimer's disease (AD) with initiation at a late disease stage. Thus, we aimed to investigate the effects of interventional late-stage Anle138b treatment, which previously indicated great potential to inhibit oligomer accumulation by binding of pathological aggregates, on the metabolic decline in transgenic mice with established tauopathy in a longitudinal F-fluorodeoxyglucose positron emission tomography (FDG-PET) study.

Methods: Twelve transgenic mice expressing all six human tau isoforms (hTau) and ten controls were imaged by FDG-PET at baseline (14.5 months), followed by randomization into Anle138b treatment and vehicle groups for 3 months. FDG-PET was repeated after treatment for 3 months, and brains were analyzed by tau immunohistochemistry. Longitudinal changes of glucose metabolism were compared between study groups, and the end point tau load was correlated with individual FDG-PET findings.

Results: Tau pathology was significantly ameliorated by late-stage Anle138b treatment when compared to vehicle (frontal cortex - 53%, p < 0.001; hippocampus - 59%, p < 0.005). FDG-PET revealed a reversal of metabolic decline during Anle138b treatment, whereas the vehicle group showed ongoing deterioration. End point glucose metabolism in the brain of hTau mice had a strong correlation with tau deposition measured by immunohistochemistry (R = 0.92, p < 0.001).

Conclusion: Late-stage oligomer modulation effectively ameliorated tau pathology in hTau mice and rescued metabolic function. Molecular imaging by FDG-PET can serve for monitoring effects of Anle138b treatment.
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http://dx.doi.org/10.1186/s13195-019-0522-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6670231PMC
August 2019

The neuropathology of fatal encephalomyelitis in human Borna virus infection.

Acta Neuropathol 2019 10 26;138(4):653-665. Epub 2019 Jul 26.

Department of Neuropathology, School of Medicine, Institute of Pathology, Technical University Munich, Trogerstraße 18, 81675, Munich, Germany.

After many years of controversy, there is now recent and solid evidence that classical Borna disease virus 1 (BoDV-1) can infect humans. On the basis of six brain autopsies, we provide the first systematic overview on BoDV-1 tissue distribution and the lesion pattern in fatal BoDV-1-induced encephalitis. All brains revealed a non-purulent, lymphocytic sclerosing panencephalomyelitis with detection of BoDV-1-typical eosinophilic, spherical intranuclear Joest-Degen inclusion bodies. While the composition of histopathological changes was constant, the inflammatory distribution pattern varied interindividually, affecting predominantly the basal nuclei in two patients, hippocampus in one patient, whereas two patients showed a more diffuse distribution. By immunohistochemistry and RNA in situ hybridization, BoDV-1 was detected in all examined brain tissue samples. Furthermore, infection of the peripheral nervous system was observed. This study aims at raising awareness to human bornavirus encephalitis as differential diagnosis in lymphocytic sclerosing panencephalomyelitis. A higher attention to human BoDV-1 infection by health professionals may likely increase the detection of more cases and foster a clearer picture of the disease.
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http://dx.doi.org/10.1007/s00401-019-02047-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6778062PMC
October 2019

Longitudinal PET Monitoring of Amyloidosis and Microglial Activation in a Second-Generation Amyloid-β Mouse Model.

J Nucl Med 2019 12 13;60(12):1787-1793. Epub 2019 Jul 13.

Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich Germany

Nonphysiologic overexpression of amyloid-β (Aβ) precursor protein in common transgenic Aβ mouse models of Alzheimer disease likely hampers their translational potential. The novel mouse incorporates a mutated knock-in, potentially presenting an improved model of Alzheimer disease for Aβ-targeting treatment trials. We aimed to establish serial small-animal PET of amyloidosis and neuroinflammation in mice as a tool for therapy monitoring. mice (20 homozygous and 21 heterogeneous) and 12 age-matched wild-type mice were investigated longitudinally from 2.5 to 10 mo of age with F-florbetaben Aβ PET and F-GE-180 18-kDa translocator protein (TSPO) PET. Voxelwise analysis of SUV ratio images was performed using statistical parametric mapping. All mice underwent a Morris water maze test of spatial learning after their final scan. Quantification of fibrillar Aβ and activated microglia by immunohistochemistry and biochemistry served for validation of the PET results. The periaqueductal gray emerged as a suitable pseudo reference tissue for both tracers. Homozygous mice had a rising SUV ratio in cortex and hippocampus for Aβ (+9.1%, +3.8%) and TSPO (+19.8%, +14.2%) PET from 2.5 to 10 mo of age (all < 0.05), whereas heterozygous mice did not show significant changes with age. Significant voxelwise clusters of Aβ deposition and microglial activation in homozygous mice appeared at 5 mo of age. Immunohistochemical and biochemical findings correlated strongly with the PET data. Water maze escape latency was significantly elevated in homozygous mice compared with wild-type at 10 mo of age and was associated with high TSPO binding. Longitudinal PET in knock-in mice enables monitoring of amyloidogenesis and neuroinflammation in homozygous mice but is insensitive to minor changes in heterozygous animals. The combination of PET with behavioral tasks in treatment trials is poised to provide important insights in preclinical drug development.
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http://dx.doi.org/10.2967/jnumed.119.227322DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6894380PMC
December 2019

Bevacizumab reduces toxicity of reirradiation in recurrent high-grade glioma.

Radiother Oncol 2019 09 25;138:99-105. Epub 2019 Jun 25.

Department of Radiation Oncology, University Hospital, LMU Munich, Germany; German Cancer Consortium (DKTK), Munich, Germany. Electronic address:

Purpose: The role of bevacizumab (BEV) in the setting of reirradiation (reRT) of malignant glioma recurrences is poorly defined. At our institution, reRT plus BEV was routinely used until its disapproval for glioma treatment by the European Medical Agency. Accordingly, reRT was applied without the addition of BEV since 2017. Here we present for the first time outcome and toxicity profiles of reRT plus BEV and reRT alone for malignant glioma recurrences.

Patients And Methods: All adult patients consecutively undergoing reRT of a recurrent malignant glioma (37 anaplastic astrocytoma, WHO III; 124 glioblastoma, WHO IV) between 2007 and 2017 were included. In one group of patients, BEV (10 mg/kg bodyweight) was applied concomitantly on days 1 and 15 of reRT. Radiation toxicity referred to clinically significant toxicities of proven symptomatic radionecrosis (RN) and symptomatic oedema (SE) requiring steroid treatment for more than six weeks after reRT. Post-recurrence survival (PRS) and freedom from RN/SE were estimated with the Kaplan-Meier method. Prognostic factors were obtained from proportional hazards models.

Results: BEV plus reRT was applied in 124 and reRT alone in 37 patients. Both groups were comparable in terms of their patient-, tumour-, and RT/reRT-related variables. PRS was independent from the applied reRT protocols. RN/SE was less frequently seen after reRT plus BEV absolutely (27/124 (21.8%) vs. 14/37 (37.8%) patients; p = 0.025) and over time (1-year RN/SE rate: 23.9% vs. 54.1%; p = 0.013). The unadjusted and adjusted hazard ratio for RN/SE was doubled in case of reRT alone. Absence of BEV remained the only risk factor for RN/SE in multivariate models (p = 0.026).

Conclusion: Concomitant BEV effectively reduces treatment toxicity of reRT and should be reconsidered in future reRT protocols.
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http://dx.doi.org/10.1016/j.radonc.2019.06.009DOI Listing
September 2019

Unbalanced calcium channel activity underlies selective vulnerability of nigrostriatal dopaminergic terminals in Parkinsonian mice.

Sci Rep 2019 03 19;9(1):4857. Epub 2019 Mar 19.

Transgenic Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA.

Dopamine (DA) release in striatum is functionally segregated across a dorsolateral/ventromedial axis. Interestingly, nigrostriatal DA signaling disruption in Parkinson's disease (PD) preferentially affects the dorsolateral striatum. The relationship between afferent presynaptic calcium transients (PreCaTs) in DA terminals and DA release in dorsolateral (Caudato-Putamen, DLS) and ventromedial (Nucleus Accumbens Shell, VS) striatal subregions was examined by ex vivo real-time dual-recording in conditional transgenic mice expressing the calcium indicator protein GCaMP3. In DLS, minimal increases in cytosolic calcium trigger steep DA release while PreCaTs and DA release in VS both were proportional to the number of pulses in burst stimulation. Co-expressing α-synuclein with the Parkinson's disease (PD)-associated A53T mutation and GCaMP3 in midbrain DA neurons revealed augmented cytosolic steady state and activity-dependent intra-terminal calcium levels preferentially in DLS, as well as hyperactivation and enhanced expression of N-type calcium channels. Thus, unbalanced calcium channel activity is a presynaptic mechanism to consider in the multifaceted pathogenic pathways of progressive neurodegeneration.
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http://dx.doi.org/10.1038/s41598-019-41091-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6425036PMC
March 2019

In vivo imaging reveals reduced activity of neuronal circuits in a mouse tauopathy model.

Brain 2019 04;142(4):1051-1062

Department for Translational Brain Research, German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.

Pathological alterations of tau protein play a significant role in the emergence and progression of neurodegenerative disorders. Tauopathies are characterized by detachment of the tau protein from neuronal microtubules, and its subsequent aberrant hyperphosphorylation, aggregation and cellular distribution. The exact nature of tau protein species causing neuronal malfunction and degeneration is still unknown. In the present study, we used mice transgenic for human tau with the frontotemporal dementia with parkinsonism-associated P301S mutation. These mice are prone to develop fibrillar tau inclusions, especially in the spinal cord and brainstem. At the same time, cortical neurons are not as strongly affected by fibrillar tau forms, but rather by soluble tau forms. We took advantage of the possibility to induce formation of neurofibrillary tangles in a subset of these cortical neurons by local injection of preformed synthetic tau fibrils. By using chronic in vivo two-photon calcium imaging in awake mice, we were able for the first time to follow the activity of individual tangle-bearing neurons and compare it to the activity of tangle-free neurons over the disease course. Our results revealed strong reduction of calcium transient frequency in layer 2/3 cortical neurons of P301S mice, independent of neurofibrillary tangle presence. These results clearly point to the impairing role of soluble, mutated tau protein species present in the majority of the neurons investigated in this study.
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http://dx.doi.org/10.1093/brain/awz035DOI Listing
April 2019

Translational control in brain pathologies: biological significance and therapeutic opportunities.

Acta Neuropathol 2019 04 9;137(4):535-555. Epub 2019 Feb 9.

Department of Molecular Oncology, British Columbia Cancer Research Centre, Vancouver, BC, V5Z 1L3, Canada.

Messenger RNA (mRNA) translation is the terminal step in protein synthesis, providing a crucial regulatory checkpoint for this process. Translational control allows specific cell types to respond to rapid changes in the microenvironment or to serve specific functions. For example, neurons use mRNA transport to achieve local protein synthesis at significant distances from the nucleus, the site of RNA transcription. Altered expression or functions of the various components of the translational machinery have been linked to several pathologies in the central nervous system. In this review, we provide a brief overview of the basic principles of mRNA translation, and discuss alterations of this process relevant to CNS disease conditions, with a focus on brain tumors and chronic neurological conditions. Finally, synthesizing this knowledge, we discuss the opportunities to exploit the biology of altered mRNA translation for novel therapies in brain disorders, as well as how studying these alterations can shed new light on disease mechanisms.
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http://dx.doi.org/10.1007/s00401-019-01971-8DOI Listing
April 2019

Genome-wide analyses as part of the international FTLD-TDP whole-genome sequencing consortium reveals novel disease risk factors and increases support for immune dysfunction in FTLD.

Authors:
Cyril Pottier Yingxue Ren Ralph B Perkerson Matt Baker Gregory D Jenkins Marka van Blitterswijk Mariely DeJesus-Hernandez Jeroen G J van Rooij Melissa E Murray Elizabeth Christopher Shannon K McDonnell Zachary Fogarty Anthony Batzler Shulan Tian Cristina T Vicente Billie Matchett Anna M Karydas Ging-Yuek Robin Hsiung Harro Seelaar Merel O Mol Elizabeth C Finger Caroline Graff Linn Öijerstedt Manuela Neumann Peter Heutink Matthis Synofzik Carlo Wilke Johannes Prudlo Patrizia Rizzu Javier Simon-Sanchez Dieter Edbauer Sigrun Roeber Janine Diehl-Schmid Bret M Evers Andrew King M Marsel Mesulam Sandra Weintraub Changiz Geula Kevin F Bieniek Leonard Petrucelli Geoffrey L Ahern Eric M Reiman Bryan K Woodruff Richard J Caselli Edward D Huey Martin R Farlow Jordan Grafman Simon Mead Lea T Grinberg Salvatore Spina Murray Grossman David J Irwin Edward B Lee EunRan Suh Julie Snowden David Mann Nilufer Ertekin-Taner Ryan J Uitti Zbigniew K Wszolek Keith A Josephs Joseph E Parisi David S Knopman Ronald C Petersen John R Hodges Olivier Piguet Ethan G Geier Jennifer S Yokoyama Robert A Rissman Ekaterina Rogaeva Julia Keith Lorne Zinman Maria Carmela Tartaglia Nigel J Cairns Carlos Cruchaga Bernardino Ghetti Julia Kofler Oscar L Lopez Thomas G Beach Thomas Arzberger Jochen Herms Lawrence S Honig Jean Paul Vonsattel Glenda M Halliday John B Kwok Charles L White Marla Gearing Jonathan Glass Sara Rollinson Stuart Pickering-Brown Jonathan D Rohrer John Q Trojanowski Vivianna Van Deerlin Eileen H Bigio Claire Troakes Safa Al-Sarraj Yan Asmann Bruce L Miller Neill R Graff-Radford Bradley F Boeve William W Seeley Ian R A Mackenzie John C van Swieten Dennis W Dickson Joanna M Biernacka Rosa Rademakers

Acta Neuropathol 2019 06 9;137(6):879-899. Epub 2019 Feb 9.

Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL, 32224, USA.

Frontotemporal lobar degeneration with neuronal inclusions of the TAR DNA-binding protein 43 (FTLD-TDP) represents the most common pathological subtype of FTLD. We established the international FTLD-TDP whole-genome sequencing consortium to thoroughly characterize the known genetic causes of FTLD-TDP and identify novel genetic risk factors. Through the study of 1131 unrelated Caucasian patients, we estimated that C9orf72 repeat expansions and GRN loss-of-function mutations account for 25.5% and 13.9% of FTLD-TDP patients, respectively. Mutations in TBK1 (1.5%) and other known FTLD genes (1.4%) were rare, and the disease in 57.7% of FTLD-TDP patients was unexplained by the known FTLD genes. To unravel the contribution of common genetic factors to the FTLD-TDP etiology in these patients, we conducted a two-stage association study comprising the analysis of whole-genome sequencing data from 517 FTLD-TDP patients and 838 controls, followed by targeted genotyping of the most associated genomic loci in 119 additional FTLD-TDP patients and 1653 controls. We identified three genome-wide significant FTLD-TDP risk loci: one new locus at chromosome 7q36 within the DPP6 gene led by rs118113626 (p value = 4.82e - 08, OR = 2.12), and two known loci: UNC13A, led by rs1297319 (p value = 1.27e - 08, OR = 1.50) and HLA-DQA2 led by rs17219281 (p value = 3.22e - 08, OR = 1.98). While HLA represents a locus previously implicated in clinical FTLD and related neurodegenerative disorders, the association signal in our study is independent from previously reported associations. Through inspection of our whole-genome sequence data for genes with an excess of rare loss-of-function variants in FTLD-TDP patients (n ≥ 3) as compared to controls (n = 0), we further discovered a possible role for genes functioning within the TBK1-related immune pathway (e.g., DHX58, TRIM21, IRF7) in the genetic etiology of FTLD-TDP. Together, our study based on the largest cohort of unrelated FTLD-TDP patients assembled to date provides a comprehensive view of the genetic landscape of FTLD-TDP, nominates novel FTLD-TDP risk loci, and strongly implicates the immune pathway in FTLD-TDP pathogenesis.
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http://dx.doi.org/10.1007/s00401-019-01962-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6533145PMC
June 2019