Mild respiratory COVID can cause multi-lineage neural cell and myelin dysregulation

COVID survivors frequently experience lingering neurological symptoms that resemble cancer-therapy-related cognitive impairment, a syndrome for which white matter microglial reactivity and consequent neural dysregulation is central. Here, we explored the neurobiological effects of respiratory SARS-CoV-2 infection and found white-matter-selective microglial reactivity in mice and humans. Following mild respiratory COVID in mice, persistently impaired hippocampal neurogenesis, decreased oligodendrocytes, and myelin loss were evident together with elevated CSF cytokines/chemokines including CCL11. Systemic CCL11 administration specifically caused hippocampal microglial reactivity and impaired neurogenesis. Concordantly, humans with lasting cognitive symptoms post-COVID exhibit elevated CCL11 levels. Compared with SARS-CoV-2, mild respiratory influenza in mice caused similar patterns of white-matter-selective microglial reactivity, oligodendrocyte loss, impaired neurogenesis, and elevated CCL11 at early time points, but after influenza, only elevated CCL11 and hippocampal pathology persisted. These findings illustrate similar neuropathophysiology after cancer therapy and respiratory SARS-CoV-2 infection which may contribute to cognitive impairment following even mild COVID.

Disruption of neural progenitors along the ventricular and subventricular zones in periventricular heterotopia

Periventricular heterotopia (PH) is a disorder characterized by neuronal nodules, ectopically positioned along the lateral ventricles of the cerebral cortex. Mutations in either of two human genes, Filamin A (FLNA) or ADP-ribosylation factor guanine exchange factor 2 (ARFGEF2), cause PH (Fox et al. in 'Mutations in filamin 1 prevent migration of cerebral cortical neurons in human periventricular heterotopia'. Neuron, 21, 1315-1325, 1998; Sheen et al. in 'Mutations in ARFGEF2 implicate vesicle trafficking in neural progenitor proliferation and migration in the human cerebral cortex'. Nat. Genet., 36, 69-76, 2004). Recent studies have shown that mutations in mitogen-activated protein kinase kinase kinase-4 (Mekk4), an indirect interactor with FlnA, also lead to periventricular nodule formation in mice (Sarkisian et al. in 'MEKK4 signaling regulates filamin expression and neuronal migration'. Neuron, 52, 789-801, 2006). Here we show that neurons in post-mortem human PH brains migrated appropriately into the cortex, that periventricular nodules were primarily composed of later-born neurons, and that the neuroependyma was disrupted in all PH cases. As studied in the mouse, loss of FlnA or Big2 function in neural precursors impaired neuronal migration from the germinal zone, disrupted cell adhesion and compromised neuroepithelial integrity. Finally, the hydrocephalus with hop gait (hyh) mouse, which harbors a mutation in Napa [encoding N-ethylmaleimide-sensitive factor attachment protein alpha (alpha-SNAP)], also develops a progressive denudation of the neuroepithelium, leading to periventricular nodule formation. Previous studies have shown that Arfgef2 and Napa direct vesicle trafficking and fusion, whereas FlnA associates dynamically with the Golgi membranes during budding and trafficking of transport vesicles. Our current findings suggest that PH formation arises from a final common pathway involving disruption of vesicle trafficking, leading to impaired cell adhesion and loss of neuroependymal integrity.

Genomic and functional profiling of human Down syndrome neural progenitors implicates S100B and aquaporin 4 in cell injury

Down syndrome (DS) is caused by trisomy of chromosome 21 and is characterized by mental retardation, seizures and premature Alzheimer's disease. To examine neuropathological mechanisms giving rise to this disorder, we generated multiple human DS neural progenitor cell (NPC) lines from the 19-21 week frontal cortex and characterized their genomic and functional properties. Microarray profiling of DS progenitors indicated that increased levels of gene expression were not limited to chromosome 21, suggesting that increased expression of genes on chromosome 21 altered transcriptional regulation of a subset of genes throughout the entire genome. Moreover, many transcriptionally dysregulated genes were involved in cell death and oxidative stress. Network analyses suggested that upregulated expression of chromosome 21 genes such as S100B and amyloid precursor protein activated the stress response kinase pathways, and furthermore, could be linked to upregulation of the water channel aquaporin 4 (AQP4). We further demonstrate in DS NPCs that S100B is constitutively overexpressed, that overexpression leads to increased reactive oxygen species (ROS) formation and activation of stress response kinases, and that activation of this pathway results in compensatory AQP4 expression. In addition, AQP4 expression could be induced by direct exposure to ROS, and siRNA inhibition of AQP4 resulted in elevated levels of ROS following S100B exposure. Finally, elevated levels of S100B-induced ROS and loss of AQP4 expression led to increased programmed cell death. These findings suggest that dysregulation of chromosome 21 genes in DS neural progenitors leads to increased ROS and thereby alters transcriptional regulation of cytoprotective, non-chromosome 21 genes in response to ongoing cellular insults.

Telepathology diagnosis by means of digital still images: an international validation study

Telepathology affords the means to provide pathological diagnosis and consultation to remote sites. However, before telepathology can become an acceptable medical tool, it will be vital to determine the diagnostic accuracy of this technology. We report the results of a single-blind study of the accuracy of diagnosis performed using computerized still images obtained from a telepathology workstation used in a French telepathology network. Four pathologists, each working alone, reviewed a total of 200 cases of routine surgical pathology (50 cases each), and performed diagnosis based on both computer CD-ROM still images (CD) and conventional glass slides (GS). Concordance between GS and CD diagnosis, as well as accuracy, were determined. Other factors related to performance were also measured, including diagnostic certainty, reasons for uncertainty, and causes of diagnostic error. Overall, there was good agreement between CS and CD diagnosis. There was 87.5% concordance between CS and CD diagnosis, and comparison to consensus (correct) diagnosis showed accuracy of 95.5% and 88.5% for GS and CD diagnosis, respectively. Marked variability in accuracy of CD diagnosis was observed among the four pathologists, and issues related to image selection and/or quality appeared responsible for 60% of the diagnostic errors. The lack of sufficient images and clinical information were frequently cited as reasons for diagnostic uncertainty, as well as feelings of insufficient expertise. It is likely that the opportunity for interaction with the referring pathologist and the use of subspecialty consultants would likely improve the performance of telepathology.

Mild respiratory SARS-CoV-2 infection can cause multi-lineage cellular dysregulation and myelin loss in the brain

Survivors of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) infection frequently experience lingering neurological symptoms, including impairment in attention, concentration, speed of information processing and memory. This long-COVID cognitive syndrome shares many features with the syndrome of cancer therapy-related cognitive impairment (CRCI). Neuroinflammation, particularly microglial reactivity and consequent dysregulation of hippocampal neurogenesis and oligodendrocyte lineage cells, is central to CRCI. We hypothesized that similar cellular mechanisms may contribute to the persistent neurological symptoms associated with even mild SARS-CoV-2 respiratory infection. Here, we explored neuroinflammation caused by mild respiratory SARS-CoV-2 infection - without neuroinvasion - and effects on hippocampal neurogenesis and the oligodendroglial lineage. Using a mouse model of mild respiratory SARS-CoV-2 infection induced by intranasal SARS-CoV-2 delivery, we found white matter-selective microglial reactivity, a pattern observed in CRCI. Human brain tissue from 9 individuals with COVID-19 or SARS-CoV-2 infection exhibits the same pattern of prominent white matter-selective microglial reactivity. In mice, pro-inflammatory CSF cytokines/chemokines were elevated for at least 7-weeks post-infection; among the chemokines demonstrating persistent elevation is CCL11, which is associated with impairments in neurogenesis and cognitive function. Humans experiencing long-COVID with cognitive symptoms (48 subjects) similarly demonstrate elevated CCL11 levels compared to those with long-COVID who lack cognitive symptoms (15 subjects). Impaired hippocampal neurogenesis, decreased oligodendrocytes and myelin loss in subcortical white matter were evident at 1 week, and persisted until at least 7 weeks, following mild respiratory SARS-CoV-2 infection in mice. Taken together, the findings presented here illustrate striking similarities between neuropathophysiology after cancer therapy and after SARS-CoV-2 infection, and elucidate cellular deficits that may contribute to lasting neurological symptoms following even mild SARS-CoV-2 infection.

Systemic metastasis in glioblastoma may represent the emergence of neoplastic subclones

Glioblastomas only rarely metastasize to sites outside the central nervous system, for reasons that are poorly understood. We report the clinicopathological and molecular genetic findings in 6 patients with metastatic glioblastoma. Four patients were under the age of 32 and all but 1 patient died within 2 yr of diagnosis. The number of metastases ranged from 1 to 3. At the time of death, 3 patients had apparent tumor control at their primary site. We evaluated DNA from both primary and metastatic glioblastomas for genetic alterations commonly found in glioblastomas: TP53 mutations, CDKN2A/p16 deletions, EGFR amplification, and allelic loss of chromosomes 1p, 10q and 19q. Four of 6 cases had TP53 mutations and only single cases had EGFR amplification, CDKN2A/p16 deletions, or allelic loss of 1p, 10q and 19q; 2 cases had no detectable genetic alterations. In 2 cases, the primary and metastatic tumors had identical genotypes. Remarkably, however, 2 cases had different TP53 alterations in the primary and metastatic lesions, or among the metastatic tumors, which suggests that some metastatic deposits may represent emergence of subclones that were not necessarily dominant in the primary tumor. The present observations and a review of the recent literature demonstrate that metastatic glioblastomas tend to occur in younger adults who do not follow long clinical courses, and may be characterized by TP53 mutations and differential clonal selection.

Overlapping expression of ARFGEF2 and Filamin A in the neuroependymal lining of the lateral ventricles: Insights into the cause of periventricular heterotopia

Periventricular heterotopia (PH) is a malformation of cortical development characterized by nodules of neurons, ectopically located along the lateral ventricles of the brain. Mutations in the vesicle transport ADP-ribosylation factor guanine exchange factor 2 gene (ARFGEF2) or the actin-binding Filamin A (FLNA) gene cause PH. Previous studies have shown that FLNA expression is developmentally regulated, with strongest expression observed along the ventricular zone (VZ) and to a lesser degree in postmitotic neurons in the cortex. Here we characterize the expression patterns for ARFGEF2 within the central nervous systems of human and mouse in order to better understand their potential roles in causing PH. ARFGEF2 mRNA was widely expressed in all cortical layers, especially in the neural precursors of the ventricular and subventricular zones (SVZ) during development, with persistent but diminished expression in adulthood. ARFGEF2 encodes for the protein brefeldin-inhibited guanine exchange factor 2 (BIG2). BIG2 protein immunoreactivity was most strongly localized to the neural progenitors along the neuroependymal lining of the VZ during development, with decreased expression in adulthood. Furthermore, overlapping BIG2 and FLNA expression was greatest in these same neuroependymal cells of human embryonic brain and was co-expressed in progenitors by Western blot. Finally, transfection of a dominant-negative construct of ARFGEF2 in SHSY5Y neuroblastoma cells partially blocked FLNA transport from the Golgi apparatus to the cell membrane. These results suggest that mutations in ARFGEF2 may impair targeted transport of FLNA to the cell surface within neural progenitors along the neuroependyma and that disruption of these cells could contribute to PH formation.

Dual-isotope single-photon emission computerized tomography scanning in patients with glioblastoma multiforme: association with patient survival and histopathological characteristics of tumor after high-dose radiotherapy

OBJECT

The study was conducted to determine the association between dual-isotope single-photon emission computerized tomography (SPECT) scanning and histopathological findings of tumor recurrence and survival in patients treated with high-dose radiotherapy for glioblastoma multiforme.

METHODS

Studies in which SPECT with 201Tl and 99mTc-hexamethypropyleneamine oxime (HMPAO) were used were performed 1 day before reoperation in 47 patients with glioblastoma multiforme who had previously been treated by surgery and high-dose radiotherapy. Maximum uptake of 201Tl in the lesion was expressed as a ratio to that in the contralateral scalp, and uptake of 99mTc-HMPAO was expressed as a ratio to that in the cerebellar cortex. Patients were stratified into groups based on the maximum radioisotope uptake values in their tumor beds. The significance of differences in patient gender, histological characteristics of tissue at reoperation, and SPECT uptake group with respect to 1-year survival was elucidated by using the chi-square statistic. Comparisons of patient ages and time to tumor recurrence as functions of 1-year survival were made using the t-test. Survival data at 1 year were presented according to the Kaplan-Meier method, and the significance of potential differences was evaluated using the log-rank method. The effects of different variables (tumor type, time to recurrence, and SPECT grouping) on long-term survival were evaluated using Cox proportional models that controlled for age and gender. All patients in Group I (201Tl ratio < 2 and 99mTc-HMPAO ratio < 0.5) showed radiation changes in their biopsy specimens: they had an 83.3% 1-year survival rate. Group II patients (201Tl ratio < 2 and 99mTc-HMPAO ratio of > or = 0.5 or 201Tl ratio between 2 and 3.5 regardless of 99mTc-HMPAO ratio) had predominantly infiltrating tumor (66.6%); they had a 29.2% 1-year survival rate. Almost all of the patients in Group III (201Tl ratio > 3.5 and 99mTc-HMPAO ratio > or = 0.5) had solid tumor (88.2%) and they had a 6.7% 1-year survival rate. Histological data were associated with 1-year survival (p < 0.01): however, SPECT grouping was more closely associated with 1-year survival (p < 0.001) and was the only variable significantly associated with long-term survival (p < 0.005).

CONCLUSIONS

Dual-isotope SPECT data correlate with histopathological findings made at reoperation and with survival in patients with malignant gliomas after surgical and high-dose radiation therapy.

Integrated genome and transcriptome sequencing identifies a noncoding mutation in the genome replication factor DONSON as the cause of microcephaly-micromelia syndrome

While next-generation sequencing has accelerated the discovery of human disease genes, progress has been largely limited to the “low hanging fruit” of mutations with obvious exonic coding or canonical splice site impact. In contrast, the lack of high-throughput, unbiased approaches for functional assessment of most noncoding variants has bottlenecked gene discovery. We report the integration of transcriptome sequencing (RNA-seq), which surveys all mRNAs to reveal functional impacts of variants at the transcription level, into the gene discovery framework for a unique human disease, microcephaly-micromelia syndrome (MMS). MMS is an autosomal recessive condition described thus far in only a single First Nations population and causes intrauterine growth restriction, severe microcephaly, craniofacial anomalies, skeletal dysplasia, and neonatal lethality. Linkage analysis of affected families, including a very large pedigree, identified a single locus on Chromosome 21 linked to the disease (LOD > 9). Comprehensive genome sequencing did not reveal any pathogenic coding or canonical splicing mutations within the linkage region but identified several nonconserved noncoding variants. RNA-seq analysis detected aberrant splicing in DONSON due to one of these noncoding variants, showing a causative role for DONSON disruption in MMS. We show that DONSON is expressed in progenitor cells of embryonic human brain and other proliferating tissues, is co-expressed with components of the DNA replication machinery, and that Donson is essential for early embryonic development in mice as well, suggesting an essential conserved role for DONSON in the cell cycle. Our results demonstrate the utility of integrating transcriptomics into the study of human genetic disease when DNA sequencing alone is not sufficient to reveal the underlying pathogenic mutation.

Impaired proliferation and migration in human Miller-Dieker neural precursors

OBJECTIVE

Miller-Dieker syndrome (MDS) is a malformation of cortical development that results in lissencephaly (meaning smooth brain). This disorder is caused by heterozygous deletions on chromosome 17p13.3, including the lissencephaly 1 (LIS1) gene. Various mouse models have been used as an experimental paradigm in understanding human lissencephaly, but clear limitations exist in these studies, particularly because mice are naturally lissencephalic. Thus, the objective of this article was to establish human neural precursor cell lines from postmortem MDS tissue and to characterize the pathological cellular processes that contribute to the human lissencephalic phenotype.

METHODS

Human neural precursors were isolated and expanded from the frontal cortices of a 33-week postmortem fetus with MDS and an age-matched control subject. Relative rates of proliferation and cell death were assessed in vitro, whereas the migration of precursors was examined after transplantation in vivo.

RESULTS

Precursors showed haploinsufficiency of the LIS1 gene and a reduction in LIS1 protein. Precursors could also differentiate into both neurons and glia. MDS precursors demonstrated impairments in neuronal migration, diminished rates of cell proliferation, and increased cell death.

INTERPRETATION

These results suggest that, in addition to migration, disruption in cell proliferation could play a more important role in the development of lissencephaly than previously suspected.

Mutations in the substrate binding glycine-rich loop of the mitochondrial processing peptidase-α protein (PMPCA) cause a severe mitochondrial disease

We describe a large Lebanese family with two affected members, a young female proband and her male cousin, who had multisystem involvement including profound global developmental delay, severe hypotonia and weakness, respiratory insufficiency, blindness, and lactic acidemia—findings consistent with an underlying mitochondrial disorder. Whole-exome sequencing was performed on DNA from the proband and both parents. The proband and her cousin carried compound heterozygous mutations in the PMPCA gene that encodes for α-mitochondrial processing peptidase (α-MPP), a protein likely involved in the processing of mitochondrial proteins. The variants were located close to and postulated to affect the substrate binding glycine-rich loop of the α-MPP protein. Functional assays including immunofluorescence and western blot analysis on patient's fibroblasts revealed that these variants reduced α-MPP levels and impaired frataxin production and processing. We further determined that those defects could be rescued through the expression of exogenous wild-type PMPCA cDNA. Our findings link defective α-MPP protein to a severe mitochondrial disease.

Characterization of the expression of HTm4 (MS4A3), a cell cycle regulator, in human peripheral blood cells and normal and malignant tissues

HTm4 (MS4A3) is a member of a family of four-transmembrane proteins designated MS4A. MS4A proteins fulfil diverse functions, acting as cell surface signalling molecules and intracellular adapter proteins. Early reports demonstrated that HTm4 is largely restricted to the haematopoietic lineage, and is involved in cell cycle control, via a regulatory interaction with the kinase-associated phosphatase, cyclin A and cyclin-dependent kinase 2 (CDK2). Here we describe the expression pattern of HTm4 in peripheral blood cells using gene expression microarray technology, and in normal foetal and adult human tissues, as well as adult human cancers, using tissue microarray technology. Using oligonucleotide microarrays to evaluate HTm4 mRNA, all peripheral blood cell types demonstrated very low levels of HTm4 expression; however, HTm4 expression was greatest in basophils compared to eosinophils, which showed lower levels of HTm4 expression. Very weak HTm4 expression is found in monocytes, granulocytes and B cells, but not in T cells, by lineage specific haematopoietic cell flow cytometry analysis. Interestingly, phytohaemagglutinin stimulation increases HTm4 protein expression in peripheral blood CD4-T-lymphocytes over nearly undetectable baseline levels. Western blotting and immunohistochemical studies show strong HTm4 expression in the developing haematopoietic cells of human foetal liver. Immunohistochemical studies on normal tissue microarrays confirmed HTm4 expression in a subset of leucocytes in nodal, splenic tissues and thymic tissue, and weak staining in small numbers of cell types in non-haematopoietic tissues. Human foetal brain specimens from 19 to 31 gestational weeks showed that the strongest-staining cells are ventricular zone cells and the earliest-born, earliest-differentiating ‘pioneer’ neurons in the cortical plate, Cajal-Retzius and, to a lesser extent, subplate-like neurons. Malignant tissue microarray analysis showed HTm4 expression in a wide variety of adenocarcinomas, including breast, prostate and ovarian. These findings warrant the further study of the role of HTm4 in the cell cycle of both haematopoietic and tumour cells.

Detection of astrocytic tau pathology facilitates recognition of chronic traumatic encephalopathy neuropathologic change

Traumatic brain injury (TBI) is associated with the development of a range of neurodegenerative pathologies, including chronic traumatic encephalopathy (CTE). Current consensus diagnostic criteria define the pathognomonic cortical lesion of CTE neuropathologic change (CTE-NC) as a patchy deposition of hyperphosphorylated tau in neurons, with or without glial tau in thorn-shaped astrocytes, typically towards the depths of sulci and clustered around small blood vessels. Nevertheless, although incorporated into consensus diagnostic criteria, the contribution of the individual cellular components to identification of CTE-NC has not been formally evaluated. To address this, from the Glasgow TBI Archive, cortical tissue blocks were selected from consecutive brain donations from contact sports athletes in which there was known to be either CTE-NC (n = 12) or Alzheimer's disease neuropathologic change  (n = 4). From these tissue blocks, adjacent tissue sections were stained for tau antibodies selected to reveal either solely neuronal pathology (3R tau; GT-38) or mixed neuronal and astroglial pathologies (4R tau; PHF-1). These stained sections were then randomised and independently assessed by a panel of expert neuropathologists, blind to patient clinical history and primary antibody applied to each section, who were asked to record whether CTE-NC was present. Results demonstrate that, in sections stained for either 4R tau or PHF-1, consensus recognition of CTE-NC was high. In contrast, recognition of CTE-NC in sections stained for 3R tau or GT-38 was poor; in the former no better than chance. Our observations demonstrate that the presence of both neuronal and astroglial tau pathologies facilitates detection of CTE-NC, with its detection less consistent when neuronal tau pathology alone is visible. The combination of both glial and neuronal pathologies, therefore, may be required for detection of CTE-NC.

Cavernous angioma of the posterior fossa dura mimicking a meningioma: case report and review of literature

A cavernous angioma of the posterior fossa dura was discovered incidentally on neuroimaging studies. The clinical and pathologic features of this lesion are described. Although it has been reported to arise in the posterior fossa and the tentorium cerebelli, we present the first case of such a malformation arising from the dura of the posterior fossa.

Atypical lymphohistiocytic infiltrate (pseudolymphoma) of the oral cavity

In the oral cavity, differentiation between reactive and neoplastic lymphoproliferative lesions can, at times, be very difficult. We report an unusual case in which immunohistochemical findings were necessary to determine that the lesion was reactive despite the original interpretation of malignant lymphoma. The relationship of this lesion to atypical histiocytic granuloma, angiolymphoid hyperplasia with eosinophilia, and traumatic ulcerative granuloma with stromal eosinophilia is discussed and possible pathogenetic mechanisms are proposed. The value of immunohistochemistry in the diagnosis of extranodal lymphoproliferative lesions is emphasized.

Neocortical neuronal arrangement in Miller Dieker syndrome

Miller Dieker syndrome (MDS, type I lissencephaly) is a neuronal migration disorder, which is caused by deletions along the short arm of chromosome 17 (17p13.3). Recent studies would suggest that the cortical lamination in MDS is inverted, based on morphological criteria. The present neuropathological study examines the cerebral cortex from a 33-week old fetus with MDS using both neuronal and laminar-specific markers. These expression studies demonstrate a relatively preserved cortex and cortical lamination, overlying a layer of immature neurons in MDS brain. The findings are consistent with both a migratory and proliferative defect, giving rise to lissencephaly. Moreover, characterization of such rare human malformations of cortical development by immunohistochemical techniques will provide a greater understanding of the underlying mechanisms.

COVID-19-Induced Neurovascular Injury: a Case Series with Emphasis on Pathophysiological Mechanisms

Coronavirus disease 2019 (COVID-19) is associated with a high inflammatory burden that can induce severe respiratory disease among other complications; vascular and neurological damage has emerged as a key threat to COVID-19 patients. Risk of severe infection and mortality increases with age, male sex, and comorbidities including cardiovascular disease, hypertension, obesity, diabetes, and chronic pulmonary disease. We review clinical and neuroradiological findings in five patients with COVID-19 who suffered severe neurological disease and illustrate the pathological findings in a 7-year-old boy with COVID-19-induced encephalopathy whose brain tissue sample showed angiocentric mixed mononuclear inflammatory infiltrate. We summarize the structural and functional properties of the virus including the molecular processes that govern the binding to its membrane receptors and cellular entry. In addition, we review clinical and experimental evidence in patients and animal models that suggests coronaviruses enter into the central nervous system (CNS), either via the olfactory bulb or through hematogenous spread. We discuss suspected pathophysiological mechanisms including direct cellular infection and associated recruitment of immune cells and neurovirulence, at least in part, mediated by cytokine secretion. Moreover, contributing to the vascular and neurological injury, coagulopathic disorders play an important pathogenic role. We survey the molecular events that contribute to the thrombotic microangiopathy. We describe the neurological complications associated with COVID-19 with a focus on the potential mechanisms of neurovascular injury. Our thesis is that following infection, three main pathophysiological processes-inflammation, thrombosis, and vascular injury-are responsible for the neurological damage and diverse pathology seen in COVID-19 patients.

Generation of neural stem cells from discarded human fetal cortical tissue

Neural stem cells (NSCs) reside along the ventricular zone neuroepithelium during the development of the cortical plate. These early progenitors ultimately give rise to intermediate progenitors and later, the various neuronal and glial cell subtypes that form the cerebral cortex. The capacity to generate and expand human NSCs (so called neurospheres) from discarded normal fetal tissue provides a means with which to directly study the functional aspects of normal human NSC development. This approach can also be directed toward the generation of NSCs from known neurological disorders, thereby affording the opportunity to identify disease processes that alter progenitor proliferation, migration and differentiation. We have focused on identifying pathological mechanisms in human Down syndrome NSCs that might contribute to the accelerated Alzheimer's disease phenotype. Neither in vivo nor in vitro mouse models can replicate the identical repertoire of genes located on human chromosome 21. Here we use a simple and reliable method to isolate Down syndrome NSCs from aborted human fetal cortices and grow them in culture. The methodology provides specific aspects of harvesting the tissue, dissection with limited anatomical landmarks, cell sorting, plating and passaging of human NSCs. We also provide some basic protocols for inducing differentiation of human NSCs into more selective cell subtypes.

Meningioangiomatosis associated with meningioma: a case report

BACKGROUND

Meningioangiomatosis is a meningovascular disorder that only rarely occurs in association with a meningioma. Occasionally, as in this case, imaging studies do not readily identify this disorder as a benign process. In addition, this disorder may infiltrate the underlying cerebral cortex, simulating, intraoperatively, a malignant infiltrative process. To allow better recognition of this disorder, we report a case with emphasis on the unique cytologic features of the 2 components (meningioangiomatosis and meningioma) and potential pitfalls in diagnosis.

CASE

A 3-year-old girl was examined in the neurosurgery service for history of refractory seizure. Neuroimaging showed an ill-defined signal abnormality in the left frontal lobe suggestive of a high-grade tumor. Tumor resection was performed, and intraoperative smear preparation showed meningioangiomatosis associated with meningioma.

CONCLUSION

Familiarity with cytologic preparations of this rare variant is very important in providing accurate intraoperative consultation. To our knowledge, this is the first description of the cytologic features on smear preparation of meningioangiomatosis occurring in association with meningioma.

COllaborative Neuropathology NEtwork Characterizing ouTcomes of TBI (CONNECT-TBI)

Efforts to characterize the late effects of traumatic brain injury (TBI) have been in progress for some time. In recent years much of this activity has been directed towards reporting of chronic traumatic encephalopathy (CTE) in former contact sports athletes and others exposed to repetitive head impacts. However, the association between TBI and dementia risk has long been acknowledged outside of contact sports. Further, growing experience suggests a complex of neurodegenerative pathologies in those surviving TBI, which extends beyond CTE. Nevertheless, despite extensive research, we have scant knowledge of the mechanisms underlying TBI-related neurodegeneration (TReND) and its link to dementia. In part, this is due to the limited number of human brain samples linked to robust demographic and clinical information available for research. Here we detail a National Institutes for Neurological Disease and Stroke Center Without Walls project, the COllaborative Neuropathology NEtwork Characterizing ouTcomes of TBI (CONNECT-TBI), designed to address current limitations in tissue and research access and to advance understanding of the neuropathologies of TReND. As an international, multidisciplinary collaboration CONNECT-TBI brings together multiple experts across 13 institutions. In so doing, CONNECT-TBI unites the existing, comprehensive clinical and neuropathological datasets of multiple established research brain archives in TBI, with survivals ranging minutes to many decades and spanning diverse injury exposures. These existing tissue specimens will be supplemented by prospective brain banking and contribute to a centralized route of access to human tissue for research for investigators. Importantly, each new case will be subject to consensus neuropathology review by the CONNECT-TBI Expert Pathology Group. Herein we set out the CONNECT-TBI program structure and aims and, by way of an illustrative case, the approach to consensus evaluation of new case donations.