Analysis of the microglia transcriptome across the human lifespan using single cell RNA sequencing.

BACKGROUND: Microglia are tissue resident macrophages with a wide range of critically important functions in central nervous system development and homeostasis. METHOD: In this study, we aimed to characterize the transcriptional landscape of ex vivo human microglia across different developmental ages using cells derived from pre-natal, pediatric, adolescent, and adult brain samples. We further confirmed our transcriptional observations using ELISA and RNAscope. RESULTS: We showed that pre-natal microglia have a distinct transcriptional and regulatory signature relative to their post-natal counterparts that includes an upregulation of phagocytic pathways. We confirmed upregulation of CD36, a positive regulator of phagocytosis, in pre-natal samples compared to adult samples in situ. Moreover, we showed adult microglia have more pro-inflammatory signature compared to microglia from other developmental ages. We indicated that adult microglia are more immune responsive by secreting increased levels of pro-inflammatory cytokines in response to LPS treatment compared to the pre-natal microglia. We further validated in situ up-regulation of IL18 and CXCR4 in human adult brain section compared to the pre-natal brain section. Finally, trajectory analysis indicated that the transcriptional signatures adopted by microglia throughout development are in response to a changing brain microenvironment and do not reflect predetermined developmental states. CONCLUSION: In all, this study provides unique insight into the development of human microglia and a useful reference for understanding microglial contribution to developmental and age-related human disease.

Spinal cord extracts of amyotrophic lateral sclerosis spread TDP-43 pathology in cerebral organoids.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder caused by progressive loss of motor neurons and there is currently no effective therapy. Cytoplasmic mislocalization and aggregation of TAR DNA-binding protein 43 kDa (TDP-43) within the CNS is a pathological hallmark in sporadic ALS and prion-like propagation of pathogenic TDP-43 is thought to be implicated in disease progression. However, cell-to-cell transmission of pathogenic TDP-43 in the human CNS has not been confirmed experimentally. Here we used induced pluripotent stem cells (iPSCs)-derived cerebral organoids as recipient CNS tissue model that are anatomically relevant human brain. We injected postmortem spinal cord protein extracts individually from three non-ALS or five sporadic ALS patients containing pathogenic TDP-43 into the cerebral organoids to validate the templated propagation and spreading of TDP-43 pathology in human CNS tissue. We first demonstrated that the administration of spinal cord extracts from an ALS patient induced the formation of TDP-43 pathology that progressively spread in a time-dependent manner in cerebral organoids, suggesting that pathogenic TDP-43 from ALS functioned as seeds and propagated cell-to-cell to form de novo TDP-43 pathology. We also reported that the administration of ALS patient-derived protein extracts caused astrocyte proliferation to form astrogliosis in cerebral organoids, reproducing the pathological feature seen in ALS. Moreover, we showed pathogenic TDP-43 induced cellular apoptosis and that TDP-43 pathology correlated with genomic damage due to DNA double-strand breaks. Thus, our results provide evidence that patient-derived pathogenic TDP-43 can mimic the prion-like propagation of TDP-43 pathology in human CNS tissue. Our findings indicate that our assays with human cerebral organoids that replicate ALS pathophysiology have a promising strategy for creating readouts that could be used in future drug discovery efforts against ALS.

Myositis with prominent B cell aggregates may meet classification criteria for sporadic inclusion body myositis.

The objective of this study was to report the clinical, serological and pathological features of patients with autoimmune myositis other than dermatomyositis, who displayed both muscle weakness on physical examination and prominent B cell aggregates on muscle pathology, defined as ≥ 30 CD20+ cells/aggregate. Specifically, the presence of a brachio-cervical inflammatory myopathies or a sporadic inclusion body myositis (sIBM) phenotype was recorded. Over a three-year period, eight patients were identified from two university neuropathology referral centers. Seven of 8 (88%) patients had an associated connective tissue disease (CTD): rheumatoid arthritis (n=3), systemic sclerosis (n=2), Sjögren's syndrome (n=1) and systemic lupus erythematosus (n=1), while one patient died on initial presentation without a complete serological and cancer investigation. A brachio-cervical phenotype, i.e. neck weakness, proximal weakness more than distal and shoulder abduction weakness greater than hip flexors, was seen in two patients (25%), while one patient had both proximal and diaphragmatic weakness. In contrast, an IBM-like clinical phenotype was seen in the last five patients (63%), who either had finger flexor weakness and/or quadriceps weakness ≤ 4 on the manual muscle testing MRC-5 scale. Although these 5 patients met at least one set of classification criteria for sIBM, an integrated clinico-sero-pathological approach argued against a diagnosis of sIBM. In summary, in a weak patient with myositis plus an associated CTD and lymphoid aggregates at muscle pathology, B cell predominant aggregates may represent a morphological biomarker against a diagnosis of sIBM.

Deep Intronic FGF14 GAA Repeat Expansion in Late-Onset Cerebellar Ataxia.

BACKGROUND: The late-onset cerebellar ataxias (LOCAs) have largely resisted molecular diagnosis. METHODS: We sequenced the genomes of six persons with autosomal dominant LOCA who were members of three French Canadian families and identified a candidate pathogenic repeat expansion. We then tested for association between the repeat expansion and disease in two independent case-control series - one French Canadian (66 patients and 209 controls) and the other German (228 patients and 199 controls). We also genotyped the repeat in 20 Australian and 31 Indian index patients. We assayed gene and protein expression in two postmortem cerebellum specimens and two induced pluripotent stem-cell (iPSC)-derived motor-neuron cell lines. RESULTS: In the six French Canadian patients, we identified a GAA repeat expansion deep in the first intron of FGF14, which encodes fibroblast growth factor 14. Cosegregation of the repeat expansion with disease in the families supported a pathogenic threshold of at least 250 GAA repeats ([GAA]≥250). There was significant association between FGF14 (GAA)≥250 expansions and LOCA in the French Canadian series (odds ratio, 105.60; 95% confidence interval [CI], 31.09 to 334.20; P<0.001) and in the German series (odds ratio, 8.76; 95% CI, 3.45 to 20.84; P<0.001). The repeat expansion was present in 61%, 18%, 15%, and 10% of French Canadian, German, Australian, and Indian index patients, respectively. In total, we identified 128 patients with LOCA who carried an FGF14 (GAA)≥250 expansion. Postmortem cerebellum specimens and iPSC-derived motor neurons from patients showed reduced expression of FGF14 RNA and protein. CONCLUSIONS: A dominantly inherited deep intronic GAA repeat expansion in FGF14 was found to be associated with LOCA. (Funded by Fondation Groupe Monaco and others.).

Autopsy Human Brain Dissection Protocol for Common Age-Related Neurodegenerative Disorders.

Age-related neurodegenerative disorders are common causes of dementia-associated morbidity and mortality in populations throughout the world. Standardized, protocol-based methods for the examination and diagnosis of these disorders allow direct comparison between human cohorts and play a key role in understanding how these disorders impact our population. Further understanding of these protocols and harmonization with animal and in vitro investigative techniques is imperative to demonstrate relevance to human disease. The following is a concise protocol for the examination of human whole brain autopsy samples, with and without spinal cord, for the examination of neurodegenerative disorders. The following protocol is designed to provide samples appropriate for most neurodegenerative diseases. The collection of both fresh-frozen and formalin-fixed tissues is described.This guide presumes general knowledge of neuroanatomy of the human central nervous system. Tissue processing, detailed histological techniques and complete diagnostic examination of the brain is beyond the scope of this chapter; however, a limited evaluation appropriate for the evaluation of neurodegenerative disease is described here. Diagnostic protocols for the most common causes of dementia-associated, age-related neurodegenerative disorders are also summarized.

Risk of Mild Cognitive Impairment or Probable Dementia in New Users of Angiotensin II Receptor Blockers and Angiotensin-Converting Enzyme Inhibitors: A Secondary Analysis of Data From the Systolic Blood Pressure Intervention Trial (SPRINT).

Importance: The cardiovascular and renal outcomes of angiotensin-II receptor blocker (ARB) and angiotensin-converting enzyme inhibitor (ACEI) treatment are well-known; however, few studies have evaluated initiation of these agents and cognitive impairment. Objective: To emulate a target trial to evaluate the cognitive outcomes of initiating an ARB- vs ACEI-based antihypertensive regimen in individuals at risk for mild cognitive impairment (MCI) and probable dementia (PD). Design, Setting, and Participants: Active comparator, new-user observational cohort study design using data from the Systolic Blood Pressure Intervention Trial (SPRINT), conducted November 2010 through July 2018. Marginal cause-specific hazard ratios (HRs) and treatment-specific cumulative incidence functions were estimated with inverse probability (IP) weighting to account for confounding. Participants were using neither an ARB nor ACEI at baseline. Data analysis was conducted from April 7, 2021, to April 26, 2022. Exposures: New users of ARB vs ACEI during the first 12 months of trial follow-up. Main Outcomes and Measures: Composite of adjudicated amnestic MCI or PD. Results: Of 9361 participants, 727 and 1313 new users of an ARB or ACEI, respectively, with well-balanced baseline characteristics between medication exposure groups after inverse probability weighting (mean [SD] age, 67 [9.5] years; 1291 ]63%] male; 240 [33%] Black; 89 [12%] Hispanic; 383 [53%] White; and 15 [2%] other race or ethnicity. In the primary analysis, during a median follow-up of 4.9 years, the inverse probability-weighted rate of amnestic MCI or PD was 4.3 vs 4.6 per 100 person-years among participants initiating ARB vs ACEI (HR, 0.93; 95% CI, 0.76-1.13). In subgroup analyses, new users of an ARB vs ACEI had a lower rate of amnestic MCI or PD among those in the standard systolic blood pressure treatment arm (HR, 0.61; 95% CI, 0.41-0.91) but not in the intensive arm (HR, 1.17; 95% CI, 0.90-1.52) (P = .007 for interaction). Conclusions and Relevance: In this observational cohort study of US adults at high cardiovascular disease risk, there was no difference in the rate of amnestic MCI or PD among new users of an ARB compared with ACEI, although 95% CIs were wide.

Regional and age-related diversity of human mature oligodendrocytes.

Morphological and emerging molecular studies have provided evidence for heterogeneity within the oligodendrocyte population. To address the regional and age-related heterogeneity of human mature oligodendrocytes (MOLs) we applied single-cell RNA sequencing to cells isolated from cortical/subcortical, subventricular zone brain tissue samples, and thoracolumbar spinal cord samples. Unsupervised clustering of cells identified transcriptionally distinct MOL subpopulations across regions. Spinal cord MOLs, but not microglia, exhibited cell-type-specific upregulation of immune-related markers compared to the other adult regions. SVZ MOLs showed an upregulation of select number of development-linked transcription factors compared to other regions; however, pseudotime trajectory analyses did not identify a global developmental difference. Age-related analysis of cortical/subcortical samples indicated that pediatric MOLs, especially from under age 5, retain higher expression of genes linked to development and to immune activity with pseudotime analysis favoring a distinct developmental stage. Our regional and age-related studies indicate heterogeneity of MOL populations in the human CNS that may reflect developmental and environmental influences.

Association of Antihypertensives That Stimulate vs Inhibit Types 2 and 4 Angiotensin II Receptors With Cognitive Impairment.

Importance: Use of antihypertensive medications that stimulate type 2 and 4 angiotensin II receptors, compared with those that do not stimulate these receptors, has been associated with a lower risk of dementia. However, this association with cognitive outcomes in hypertension trials, with blood pressure levels in the range of current guidelines, has not been evaluated. Objective: To examine the association between use of exclusively antihypertensive medication regimens that stimulate vs inhibit type 2 and 4 angiotensin II receptors on mild cognitive impairment (MCI) or dementia. Design, Setting, and Participants: This cohort study is a secondary analysis (April 2011 to July 2018) of participants in the randomized Systolic Blood Pressure Intervention Trial (SPRINT), which recruited individuals 50 years or older with hypertension and increased cardiovascular risk but without a history of diabetes, stroke, or dementia. Data analysis was conducted from March 16 to July 6, 2021. Exposures: Prevalent use of angiotensin II receptor type 2 and 4-stimulating or -inhibiting antihypertensive medication regimens at the 6-month study visit. Main Outcomes and Measures: The primary outcome was a composite of adjudicated amnestic MCI or probable dementia. Results: Of the 8685 SPRINT participants who were prevalent users of antihypertensive medication regimens at the 6-month study visit (mean [SD] age, 67.7 [11.2] years; 5586 [64.3%] male; and 935 [10.8%] Hispanic, 2605 [30.0%] non-Hispanic Black, 4983 [57.4%] non-Hispanic White, and 162 [1.9%] who responded as other race or ethnicity), 2644 (30.4%) were users of exclusively stimulating, 1536 (17.7%) inhibiting, and 4505 (51.9%) mixed antihypertensive medication regimens. During a median of 4.8 years of follow-up (95% CI, 4.7-4.8 years), there were 45 vs 59 cases per 1000 person-years of amnestic MCI or probable dementia among prevalent users of regimens that contained exclusively stimulating vs inhibiting antihypertensive medications (hazard ratio [HR], 0.76; 95% CI, 0.66-0.87). When comparing stimulating-only vs inhibiting-only users, amnestic MCI occurred at rates of 40 vs 54 cases per 1000 person-years (HR, 0.74; 95% CI, 0.64-0.87) and probable dementia at rates of 8 vs 10 cases per 1000 person-years (HR, 0.80; 95% CI, 0.57-1.14). Negative control outcome analyses suggested the presence of residual confounding. Conclusions and Relevance: In this secondary analysis of SPRINT, prevalent users of regimens that contain exclusively antihypertensive medications that stimulate vs inhibit type 2 and 4 angiotensin II receptors had lower rates of incident cognitive impairment. Residual confounding cannot be ruled out. If these results are replicated in randomized clinical trials, certain antihypertensive medications could be prioritized to prevent cognitive decline.

MicroRNA-210 regulates the metabolic and inflammatory status of primary human astrocytes.

BACKGROUND: Astrocytes are the most numerous glial cell type with important roles in maintaining homeostasis and responding to diseases in the brain. Astrocyte function is subject to modulation by microRNAs (miRs), which are short nucleotide strands that regulate protein expression in a post-transcriptional manner. Understanding the miR expression profile of astrocytes in disease settings provides insight into the cellular stresses present in the microenvironment and may uncover pathways of therapeutic interest. METHODS: Laser-capture microdissection was used to isolate human astrocytes surrounding stroke lesions and those from neurological control tissue. Astrocytic miR expression profiles were examined using quantitative reverse transcription polymerase chain reaction (RT-qPCR). Primary human fetal astrocytes were cultured under in vitro stress conditions and transfection of a miR mimic was used to better understand how altered levels of miR-210 affect astrocyte function. The astrocytic response to stress was studied using qPCR, enzyme-linked immunosorbent assays (ELISAs), measurement of released lactate, and Seahorse. RESULTS: Here, we measured miR expression levels in astrocytes around human ischemic stroke lesions and observed differential expression of miR-210 in chronic stroke astrocytes compared to astrocytes from neurological control tissue. We also identified increased expression of miR-210 in mouse white matter tissue around middle cerebral artery occlusion (MCAO) brain lesions. We aimed to understand the role of miR-210 in primary human fetal astrocytes by developing an in vitro assay of hypoxic, metabolic, and inflammatory stresses. A combination of hypoxic and inflammatory stresses was observed to upregulate miR-210 expression. Transfection with miR-210-mimic (210M) increased glycolysis, enhanced lactate export, and promoted an anti-inflammatory transcriptional and translational signature in astrocytes. Additionally, 210M transfection resulted in decreased expression of complement 3 (C3) and semaphorin 5b (Sema5b). CONCLUSIONS: We conclude that miR-210 expression in human astrocytes is modulated in response to ischemic stroke disease and under in vitro stress conditions, supporting a role for miR-210 in the astrocytic response to disease conditions. Further, the anti-inflammatory and pro-glycolytic impact of miR-210 on astrocytes makes it a potential candidate for further research as a neuroprotective agent.

18F-MK-6240 tau-PET in genetic frontotemporal dementia.

Tau is one of several proteins associated with frontotemporal dementia. While knowing which protein is causing a patient's disease is crucial, no biomarker currently exists for identifying tau in vivo in frontotemporal dementia. The objective of this study was to investigate the potential for the promising 18F-MK-6240 PET tracer to bind to tau in vivo in genetic frontotemporal dementia. We enrolled subjects with genetic frontotemporal dementia, who constitute an ideal population for testing because their pathology is already known based on their mutation. Ten participants (three with symptomatic P301L and R406W MAPT mutations expected to show tau binding, three with presymptomatic MAPT mutations and four with non-tau mutations who acted as disease controls) underwent clinical characterization, tau-PET scanning with 18F-MK-6240, amyloid-PET imaging with 18F-NAV-4694 to rule out confounding Alzheimer's pathology, and high-resolution structural MRI. Tau-PET scans of all three symptomatic MAPT carriers demonstrated at least mild 18F-MK-6240 binding in expected regions, with particularly strong binding in a subject with an R406W MAPT mutation (known to be associated with Alzheimer's like neurofibrillary tangles). Two asymptomatic MAPT carriers estimated to be 5 years from disease onset both showed modest 18F-MK-6240 binding, while one ∼30 years from disease onset did not exhibit any binding. Additionally, four individuals with symptomatic frontotemporal dementia caused by a non-tau mutation were scanned (two C9orf72; one GRN; one VCP): 18F-MK-6240 scans were negative for three subjects, while one advanced C9orf72 case showed minimal regionally non-specific binding. All 10 amyloid-PET scans were negative. Furthermore, a general linear model contrasting genetic frontotemporal dementia subjects to a set of 83 age-matched controls showed significant binding only in the MAPT carriers in selected frontal, temporal and subcortical regions. In summary, our findings demonstrate mild but significant binding of MK-6240 in amyloid-negative P301L and R406W MAPT mutation subjects, with higher standardized uptake value ratio in the R406W mutation associated with the presence of NFTs, and little non-specific binding. These results highlight that a positive 18F-MK-6240 tau-PET does not necessarily imply a diagnosis of Alzheimer's disease and point towards a potential use for 18F-MK-6240 as a biomarker in certain tauopathies beyond Alzheimer's, although further patient recruitment and autopsy studies will be necessary to determine clinical applicability.

Human Oligodendrocyte Myelination Potential; Relation to Age and Differentiation.

OBJECTIVE: Myelin regeneration in the human central nervous system relies on progenitor cells within the tissue parenchyma, with possible contribution from previously myelinating oligodendrocytes (OLs). In multiple sclerosis, a demyelinating disorder, variables affecting remyelination efficiency include age, severity of initial injury, and progenitor cell properties. Our aim was to investigate the effects of age and differentiation on the myelination potential of human OL lineage cells. METHODS: We derived viable primary OL lineage cells from surgical resections of pediatric and adult brain tissue. Ensheathment capacity using nanofiber assays and transcriptomic profiles from RNA sequencing were compared between A2B5+ antibody-selected progenitors and mature OLs (non-selected cells). RESULTS: We demonstrate that pediatric progenitor and mature cells ensheathed nanofibers more robustly than did adult progenitor and mature cells, respectively. Within both age groups, the percentage of fibers ensheathed and ensheathment length per fiber were greater for A2B5+ progenitors. Gene expression of OL progenitor markers PDGFRA and PTPRZ1 were higher in A2B5+ versus A2B5- cells and in pediatric A2B5+ versus adult A2B5+ cells. The p38 MAP kinases and actin cytoskeleton-associated pathways were upregulated in pediatric cells; both have been shown to regulate OL process outgrowth. Significant upregulation of "cell senescence" genes was detected in pediatric samples; this could reflect their role in development and the increased susceptibility of pediatric OLs to activating cell death responses to stress. INTERPRETATION: Our findings identify specific biological pathways relevant to myelination that are differentially enriched in human pediatric and adult OL lineage cells and suggest potential targets for remyelination enhancing therapies. ANN NEUROL 2022;91:178-191.

Theoretical impact of the AT(N) framework on dementia using a community autopsy sample.

The AT(N) research framework categorizes eight biomarker profiles using amyloid (A), tauopathy (T), and neurodegeneration (N), regardless of dementia status. We evaluated associations with dementia risk in a community-based cohort by approximating AT(N) profiles using autopsy-based neuropathology correlates, and considered cost implications for clinical trials for secondary prevention of dementia based on AT(N) profiles. We used Consortium to Establish a Registry for Alzheimer's Disease (moderate/frequent) to approximate A+, Braak stage (IV-VI) for T+, and temporal pole lateral ventricular dilation for (N)+. Outcomes included dementia prevalence at death and incidence in the last 5 years of life. A+T+(N)+ was the most common profile (31%). Dementia prevalence ranged from 14% (A-T-[N]-) to 79% (A+T+[N]+). Between 8% (A+T-[N]-) and 68% (A+T+[N]-) of decedents developed incident dementia in the last 5 years of life. Clinical trials would incur substantial expense to characterize AT(N). Many people with biomarker-defined preclinical Alzheimer's disease will never develop clinical dementia during life, highlighting resilience to clinical expression of AD neuropathologic changes and the need for improved tools for prediction beyond current AT(N) biomarkers.

International Consortium on the Genetics of Electroconvulsive Therapy and Severe Depressive Disorders (Gen-ECT-ic).

Recent genome-wide association studies have demonstrated that the genetic burden associated with depression correlates with depression severity. Therefore, conducting genetic studies of patients at the most severe end of the depressive disorder spectrum, those with treatment-resistant depression and who are prescribed electroconvulsive therapy (ECT), could lead to a better understanding of the genetic underpinnings of depression. Despite ECT being one of the most effective forms of treatment for severe depressive disorders, it is usually placed at the end of treatment algorithms of current guidelines. This is perhaps because ECT has controlled risk and logistical demands including use of general anaesthesia and muscle relaxants and side-effects such as short-term memory impairment. Better understanding of the genetics and biology of ECT response and of cognitive side-effects could lead to more personalized treatment decisions. To enhance the understanding of the genomics of severe depression and ECT response, researchers and ECT providers from around the world and from various depression or ECT networks, but not limited to, such as the Psychiatric Genomics Consortium, the Clinical Alliance and Research in ECT, and the National Network of Depression Centers have formed the Genetics of ECT International Consortium (Gen-ECT-ic). Gen-ECT-ic will organize the largest clinical and genetic collection to date to study the genomics of severe depressive disorders and response to ECT, aiming for 30,000 patients worldwide using a GWAS approach. At this stage it will be the largest genomic study on treatment response in depression. Retrospective data abstraction and prospective data collection will be facilitated by a uniform data collection approach that is flexible and will incorporate data from many clinical practices. Gen-ECT-ic invites all ECT providers and researchers to join its efforts.

Association Between Sepsis and Microvascular Brain Injury.

OBJECTIVES: Many survivors of sepsis suffer long-term cognitive impairment, but the mechanisms of this association remain unknown. The objective of this study was to determine whether sepsis is associated with cerebral microinfarcts on brain autopsy. DESIGN: Retrospective cohort study. SETTING AND SUBJECTS: Five-hundred twenty-nine participants of the Adult Changes in Thought, a population-based prospective cohort study of older adults carried out in Kaiser Permanente Washington greater than or equal to 65 years old without dementia at study entry and who underwent brain autopsy. MEASUREMENTS AND MAIN RESULTS: Late-life sepsis hospitalization was identified using administrative data. We identified 89 individuals with greater than or equal to 1 sepsis hospitalization during study participation, 80 of whom survived hospitalization and died a median of 169 days after discharge. Thirty percent of participants with one or more sepsis hospitalization had greater than two microinfarcts, compared with 19% participants without (χ p = 0.02); 20% of those with sepsis hospitalization had greater than two microinfarcts in the cerebral cortex, compared with 10% of those without (χ p = 0.01). The adjusted relative risk of greater than two microinfarcts was 1.61 (95% CI, 1.01-2.57; p = 0.04); the relative risk for having greater than two microinfarcts in the cerebral cortex was 2.12 (95% CI, 1.12-4.02; p = 0.02). There was no difference in Braak stage for neurofibrillary tangles or consortium to establish a registry for Alzheimer's disease score for neuritic plaques between, but Lewy bodies were less significantly common in those with sepsis. CONCLUSIONS: Sepsis was specifically associated with moderate to severe vascular brain injury as assessed by microvascular infarcts. This association was stronger for microinfarcts within the cerebral cortex, with those who experienced severe sepsis hospitalization being more than twice as likely to have evidence of moderate to severe cerebral cortical injury in adjusted analyses. Further study to identify mechanisms for the association of sepsis and microinfarcts is needed.

The contribution of the rs55705857 G allele to familial cancer risk as estimated in the Utah population database.

BACKGROUND: IDH1/2 mutated glioma has been associated with a germline risk variant, the rs55705857 G allele. The Utah Population Database (UPDB), a computerized genealogy of people in Utah, is a unique resource to evaluate cancer risk in related individuals. METHODS: One hundred and two individuals with IDH1/2 mutant or 1p/19q co-deleted glioma were genotyped and linked to the UPDB. DNA came from blood (21), tumor tissue (43), or both (38). We determined congruence between somatic and germline samples and estimated the relative risk for developing cancer to first and second-degree relatives of G and A allele carriers at rs55705857. RESULTS: Somatic (glioma) DNA had 85.7% sensitivity (CI 57.2-98.2%) and 95.8% specificity (CI 78.9-99.89%) for germline rs55705857 G allele. Forty-one patients were linked to pedigrees in the UPDB with at least three generations of data. First-degree relatives of rs55705857 G allele carriers were at significantly increased risk for developing cancer (RR = 1.72, p = 0.045, CI 1.02-2.94), and specifically for oligodendroglioma (RR = 57.61, p = 0.017, CI 2.96-320.98) or prostate cancer (RR = 4.10, p = 0.008, CI 1.62-9.58); relatives of individuals without the G allele were not at increased risk. Second-degree relatives of G allele carriers also had significantly increased risk for developing cancer (RR = 1.50, p = 0.007, CI 1.15-2.01). CONCLUSIONS: Tumor DNA may approximate genotype at the rs55705857 locus. We confirmed this locus confers an increased risk of all cancers and especially of oligodendroglioma. No increased cancer or brain tumor risk is seen in family members of individuals without the high-risk G allele.

CNS inflammation and neurodegeneration: sequelae of peripheral inoculation with spinal cord tissue in rat.

OBJECTIVE: Recent research demonstrates that victims of spinal cord injury (SCI) are at increased risk for dementia and that encephalitis can occur as a consequence of isolated SCI. We theorize that autoimmunity to the central nervous system (CNS) could explain these phenomena and undertook this study to determine whether peripheral inoculation with spinal cord homogenate on 1 or 2 occasions is associated with CNS-directed autoimmunity and neurodegeneration in a rat model. METHODS: Rats were subcutaneously inoculated with saline or 75 mg of allogeneic spinal cord tissue on 1 or 2 occasions. Animals underwent Morris Water Maze testing, and serial serum samples were collected. Animals were sacrificed 8 weeks following the first inoculation. Autoantibody titers to myelin antigens MAG and GM1 were measured in serum. Immunohistochemistry was used to identify autoantibodies targeting NeuN-labeled neurons and CC1-labeled oligodendrocytes. Quantitative real-time polymerase chain reaction (qPCR) and western blotting were performed for pro-inflammatory cytokines TNF-α, IL-1ß, and IL-6 and the cell death marker caspase 3 as well as the neurodegenerative proteins tau and ß-amyloid in both brain and spinal cord. Fluoro-Jade B was used to stain degenerating neurons, facilitating counting. RESULTS: Animals inoculated with spinal cord homogenate exhibited increased titers of autoantibodies to MAG and GM1 and autoantibodies binding to neurons and oligodendrocytes. Double-inoculated animals demonstrated a significant increase in the expression of pro-inflammatory cytokines in the brain (TNF-α, p = 0.016; IL-6, p = 0.009) as well as the spinal cord (TNF-α, p = 0.024; IL-6, p = 0.002). The number of degenerating neurons was significantly increased in the brain and spinal cord of inoculated animals (p < 0.0001 and p = 0.028, respectively). Elevated expression of tau and ß-amyloid was seen in brain of double-inoculated animals (p = 0.003 and p = 0.009, respectively). Inflammatory marker expression in the brain was positively correlated with anti-myelin autoimmune antibody titers and with tau expression in the brain. Inoculated animals showed impaired memory function in Morris Water Maze testing (p = 0.043). CONCLUSIONS: The results of these experiments demonstrate that peripheral exposure to spinal cord antigens is associated with CNS-directed autoimmunity and inflammation in the brain and spinal cord as well as degeneration of CNS cells, memory impairment, and production of neurodegenerative proteins particularly when this exposure is repeated. These data support CNS autoimmunity as a candidate mechanism for the dementia that can follow SCI and perhaps other posttraumatic dementias such as chronic traumatic encephalopathy.

Preoperative and intraoperative perfusion magnetic resonance imaging in a RELA fusion-positive anaplastic ependymoma: A case report.

BACKGROUND: Ependymomas are rare neuroepithelial tumors thought to arise from radial glial precursor cells lining the walls of the ventricles and central canal of the brain and spinal cord, respectively. Histopathological classification, according to World Health Organization criteria, has only recently defined the RELA-fusion positive ependymoma. These tumors may account for 70% of supratentorial ependymomas in children and represent an aggressive entity distinct from other ependymomas. CASE DESCRIPTION: Here we present the case of a patient with RELA-fusion positive ependymoma of the frontal lobe in whom we used preoperative and intraoperative magnetic resonance (MR) perfusion imaging. In this first demonstrated intraoperative evaluation of MR perfusion in ependymoma, increased peripheral perfusion of the lesion in a ring-like manner with a discrete cutoff around the surgical margin correlated with intraoperative findings of a clear border between the tumor and brain, as well as pathological findings of increased MIB index and hypercellularity-specifically within solid tumor components. An abnormal perfusion pattern also suggested an aggressive lesion, which was later confirmed on pathological analysis. In addition, intraoperative MR perfusion improved detection of tumor tissue in combination with traditional T1-weighted contrast-enhanced methods, which increased extent of resection. CONCLUSIONS: MR perfusion imaging may be a useful method for delineating tumor aggressiveness and borders, which can be prognostic.

Mutant IDH1 Promotes Glioma Formation In Vivo.

Isocitrate dehydrogenase 1 (IDH1) is the most commonly mutated gene in grade II-III glioma and secondary glioblastoma (GBM). A causal role for IDH1R132H in gliomagenesis has been proposed, but functional validation in vivo has not been demonstrated. In this study, we assessed the role of IDH1R132H in glioma development in the context of clinically relevant cooperating genetic alterations in vitro and in vivo. Immortal astrocytes expressing IDH1R132H exhibited elevated (R)-2-hydroxyglutarate levels, reduced NADPH, increased proliferation, and anchorage-independent growth. Although not sufficient on its own, IDH1R132H cooperated with PDGFA and loss of Cdkn2a, Atrx, and Pten to promote glioma development in vivo. These tumors resembled proneural human mutant IDH1 GBM genetically, histologically, and functionally. Our findings support the hypothesis that IDH1R132H promotes glioma development. This model enhances our understanding of the biology of IDH1R132H-driven gliomas and facilitates testing of therapeutic strategies designed to combat this deadly disease.

Lipopolysaccharide endotoxemia induces amyloid-ß and p-tau formation in the rat brain.

Amyloid beta (Aß) plaques are not specific to Alzheimer's disease and occur with aging and neurodegenerative disorders. Soluble brain Aß may be neuroprotective and increases in response to neuroinflammation. Sepsis is associated with neurocognitive compromise. The objective was to determine, in a rat endotoxemia model of sepsis, whether neuroinflammation and soluble Aß production are associated with Aß plaque and hyperphosphorylated tau deposition in the brain. Male Sprague Dawley rats received a single intraperitoneal injection of 10 mg/kg of lipopolysaccharide endotoxin (LPS). Brain and blood levels of IL-1ß, IL-6, and TNFα and cortical microglial density were measured in LPS-injected and control animals. Soluble brain Aß and p-tau were compared and Aß plaques were quantified and characterized. Brain uptake of [18F]flutemetamol was measured by phosphor imaging. LPS endotoxemia resulted in elevations of cytokines in blood and brain. Microglial density was increased in LPS-treated rats relative to controls. LPS resulted in increased soluble Aß and in p-tau levels in whole brain. Progressive increases in morphologically-diffuse Aß plaques occurred throughout the interval of observation (to 7-9 days post LPS). LPS endotoxemia resulted in increased [18F]flutemetamol in the cortex and increased cortex: white matter ratios of activity. In conclusion, LPS endotoxemia causes neuroinflammation, increased soluble Aß and Aß diffuse plaques in the brain. Aß PET tracers may inform this neuropathology. Increased p-tau in the brain of LPS treated animals suggests that downstream consequences of Aß plaque formation may occur. Further mechanistic and neurocognitive studies to understand the causes and consequences of LPS-induced neuropathology are warranted.

Associations between Use of Specific Analgesics and Concentrations of Amyloid-ß 42 or Phospho-Tau in Regions of Human Cerebral Cortex.

Analgesics are commonly used by older adults, raising the question of whether their use might contribute to dementia risk and neuropathologic changes of Alzheimer's disease (AD). The Adult Changes in Thought (ACT) study is a population-based study of brain aging and incident dementia among people 65 years or older who are community dwelling and not demented at entry. Amyloid-ß (Aß)42 and phospho-tau were quantified using Histelide in regions of cerebral cortex from 420 brain autopsies. Total standard daily doses of prescription opioid and non-aspirin nonsteroidal anti-inflammatory drug (NSAID) exposure during a defined 10-year exposure window were identified using automated pharmacy dispensing data and used to classify people as having no/low, intermediate, or high exposure. People with high NSAID exposure had significantly greater Aß42 concentration in middle frontal gyrus and superior and middle temporal gyri, but not inferior parietal lobule; no Aß42 regional concentration was associated with prescription opioid usage. People with high opioid usage had significantly greater concentration of phospho-tau in middle frontal gyrus than people with little-to-no opioid usage. Consistent with our previous studies, findings suggest that high levels of NSAID use in older individuals may promote Aß42 accumulation in cerebral cortex.