Rapid neuroinflammatory changes in human acute intracerebral hemorrhage

Objective Spontaneous intracerebral hemorrhage (ICH) is the commonest form of hemorrhagic stroke and is associated with a poor prognosis. Neurosurgical removal of intracerebral hematoma has limited benefit and no pharmacotherapies are available. In acute ICH, primary tissue damage is followed by secondary pathology, where the cellular and neuroinflammatory changes are poorly understood. Methods We studied histological changes in postmortem tissue from a cohort of spontaneous supra‐tentorial primary ICH cases (n = 27) with survival of 1–12 days, compared to a matched control group (n = 16) examined in corresponding regions. Hematoxylin–eosin and microglial (Iba1) immunolabelled sections were assessed at 0–2, 3–5, and 7–12 days post‐ICH. Results Peri‐hematoma, the observed ICH‐related changes include edema, tissue neutrophils and macrophages from day 1. Ischemic neurons and swollen endothelial cells were common at day 1 and universal after day 5, as were intramural erythrocytes within small vessel walls. Activated microglia were evident at day 1 post‐ICH. There was a significant increase in Iba1 positive area fraction at 0–2 (threefold), 3–5 (fourfold), and 7–12 days post ICH (ninefold) relative to controls. Giant microglia were detected peri‐hematoma from day 5 and consistently 7–12 days post‐ICH. Interpretation Our data indicate that neuroinflammatory processes commence from day 1 post‐ICH with changing microglial size and morphology following ICH and up to day 12. From day 5 some microglia exhibit a novel multiply nucleated morphology, which may be related to changing phagocytic function. Understanding the time course of neuroinflammatory changes, post‐ICH may reveal novel targets for therapy and brain restoration

Clinical impact of anti-inflammatory microglia and macrophage phenotypes at glioblastoma margins

Glioblastoma is a devastating brain cancer for which effective treatments are required. Tumour-associated microglia and macrophages promote glioblastoma growth in an immune-suppressed microenvironment. Most recurrences occur at the invasive margin of the surrounding brain, yet the relationships between microglia/macrophage phenotypes, T cells and programmed death-ligand 1 (an immune checkpoint) across human glioblastoma regions are understudied. In this study, we performed a quantitative immunohistochemical analysis of 15 markers of microglia/macrophage phenotypes (including anti-inflammatory markers triggering receptor expressed on myeloid cells 2 and CD163, and the low-affinity-activating receptor CD32a), T cells, natural killer cells and programmed death-ligand 1, in 59 human IDH1-wild-type glioblastoma multi-regional samples (n = 177; 1 sample at tumour core, 2 samples at the margins: the infiltrating zone and leading edge). Assessment was made for the prognostic value of markers; the results were validated in an independent cohort. Microglia/macrophage motility and activation (Iba1, CD68), programmed death-ligand 1 and CD4+ T cells were reduced, and homeostatic microglia (P2RY12) were increased in the invasive margins compared with the tumour core. There were significant positive correlations between microglia/macrophage markers CD68 (phagocytic)/triggering receptor expressed on myeloid cells 2 (anti-inflammatory) and CD8+ T cells in the invasive margins but not in the tumour core (P < 0.01). Programmed death-ligand 1 expression was associated with microglia/macrophage markers (including anti-inflammatory) CD68, CD163, CD32a and triggering receptor expressed on myeloid cells 2, only in the leading edge of glioblastomas (P < 0.01). Similarly, there was a positive correlation between programmed death-ligand 1 expression and CD8+ T-cell infiltration in the leading edge (P < 0.001). There was no relationship between CD64 (a receptor for autoreactive T-cell responses) and CD8+/CD4+ T cells, or between the microglia/macrophage antigen presentation marker HLA-DR and microglial motility (Iba1) in the tumour margins. Natural killer cell infiltration (CD335+) correlated with CD8+ T cells and with CD68/CD163/triggering receptor expressed on myeloid cells 2 anti-inflammatory microglia/macrophages at the leading edge. In an independent large glioblastoma cohort with transcriptomic data, positive correlations between anti-inflammatory microglia/macrophage markers (triggering receptor expressed on myeloid cells 2, CD163 and CD32a) and CD4+/CD8+/programmed death-ligand 1 RNA expression were validated (P < 0.001). Finally, multivariate analysis showed that high triggering receptor expressed on myeloid cells 2, programmed death-ligand 1 and CD32a expression at the leading edge were significantly associated with poorer overall patient survival (hazard ratio = 2.05, 3.42 and 2.11, respectively), independent of clinical variables. In conclusion, anti-inflammatory microglia/macrophages, CD8+ T cells and programmed death-ligand 1 are correlated in the invasive margins of glioblastoma, consistent with immune-suppressive interactions. High triggering receptor expressed on myeloid cells 2, programmed death-ligand 1 and CD32a expression at the human glioblastoma leading edge are predictors of poorer overall survival. Given substantial interest in targeting microglia/macrophages, together with immune checkpoint inhibitors in cancer, these data have major clinical implications

TREM2 Expression in the Human Brain: A Marker of Monocyte Recruitment

Abstract Mutation in the triggering receptor expressed on myeloid cells (TREM) 2 gene has been identified as a risk factor for several neurodegenerative diseases including Alzheimer’s disease (AD). Experimental studies using animal models of AD have highlighted a number of functions associated with TREM2 and its expression by microglial cells. It has therefore been assumed that this is also the case in humans. However, there is very limited information concerning the cellular expression of TREM2 in the human brain. As part of investigations of microglia using post-mortem resources provided by the Medical Research Council Cognitive Function and Ageing Studies (MRC-CFAS), we immunostained the cerebral cortex of 299 participants for TREM2 using the Sigma antibody HPA010917 and compared with the macrophage/microglial markers Iba1 and CD68. As expected, Iba1 and CD68 labelled microglia and perivascular macrophages. However, in most cases (284/299), the TREM2 antibody labelled monocytes within vascular lumens, but not microglia or perivascular macrophages. In contrast, in 5 out of 6 cases with acute infarcts, TREM2 immunoreaction identified cells within the brain parenchyma interpreted as recruited monocytes. Six cases with old infarcts contained phagocytic foamy macrophages which were CD68-positive but TREM2 negative. Our observations, using the HPA010917 anti-TREM2 antibody, suggest that TREM2 is not expressed by microglia but instead seems to be a marker of recruited monocytes in the human brain. This finding has implications with regards to the role of TREM2 as a risk factor, emphasizing the importance of systemic immune responses in the development and progression of Alzheimer’s disease.The study was supported in part by: a Special Project grant and a Programme grant from the MRC and the Department of Health; the UK NIHR Biomedical Research Centre for Ageing and Age—related Disease Award to the Newcastle-upon-Tyne Hospitals Foundation Trust; the Cambridge Brain Bank is supported by the NIHR Cambridge Biomedical Research Centre; The Cambridgeshire and Peterborough NIHR CLAHRC; Nottingham University Hospitals NHS Trust; University of Sheffield and the Sheffield Teaching Hospitals NHS Foundation Trust; The Thomas Willis Oxford Brain Collection, supported by the Oxford Biomedical Research Centre; The Walton Centre NHS Foundation Trust, Liverpool

Analysis of Mutations in AARS2 in a Series of CSF1R-Negative Patients With Adult-Onset Leukoencephalopathy With Axonal Spheroids and Pigmented Glia

IMPORTANCE: Adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) is a frequent cause of adult-onset leukodystrophy known to be caused by autosomal dominant mutations in the CSF1R (colony-stimulating factor 1) gene. The discovery that CSF1R mutations cause ALSP led to more accurate prognosis and genetic counseling for these patients in addition to increased interest in microglia as a target in neurodegeneration. However, it has been known since the discovery of the CSF1R gene that there are patients with typical clinical and radiologic evidence of ALSP who do not carry pathogenic CSF1R mutations. These patients include those in whom the pathognomonic features of axonal spheroids and pigmented microglia have been found. Achieving a genetic diagnosis in these patients is important to our understanding of this disorder. OBJECTIVE: To genetically characterize a group of patients with typical features of ALSP who do not carry CSF1R mutations. DESIGN, SETTING, AND PARTICIPANTS: In this case series study, 5 patients from 4 families were identified with clinical, radiologic, or pathologic features of ALSP in whom CSF1R mutations had been excluded previously by sequencing. Data were collected between May 2014 and September 2015 and analyzed between September 2015 and February 2016. MAIN OUTCOMES AND MEASURES: Focused exome sequencing was used to identify candidate variants. Family studies, long-range polymerase chain reaction with cloning, and complementary DNA sequencing were used to confirm pathogenicity. RESULTS: Of these 5 patients, 4 were men (80%); mean age at onset of ALSP was 29 years (range, 15-44 years). Biallelic mutations in the alanyl-transfer (t)RNA synthetase 2 (AARS2) gene were found in all 5 patients. Frameshifting and splice site mutations were common, found in 4 of 5 patients, and sequencing of complementary DNA from affected patients confirmed that the variants were loss of function. All patients presented in adulthood with prominent cognitive, neuropsychiatric, and upper motor neuron signs. Magnetic resonance imaging in all patients demonstrated a symmetric leukoencephalopathy with punctate regions of restricted diffusion, typical of ALSP. In 1 patient, brain biopsy demonstrated axonal spheroids and pigmented microglia, which are the pathognomonic signs of ALSP. CONCLUSIONS AND RELEVANCE: This work indicates that mutations in the tRNA synthetase AARS2 gene cause a recessive form of ALSP. The CSF1R and AARS2 proteins have different cellular functions but overlap in a final common pathway of neurodegeneration. This work points to novel targets for research and will lead to improved diagnostic rates in patients with adult-onset leukoencephalopathy

Traumatic brain injury as a risk factor for Alzheimer disease. Comparison of two retrospective autopsy cohorts with evaluation of ApoE genotype

BACKGROUND AND PURPOSE: The impact of traumatic brain injury (TBI) on the pathogenesis of Alzheimer disease (AD) is still controversial. The aim of our retrospective autopsy study was to assess the impact of TBE and ApoE allele frequency on the development of AD. MATERIAL AND METHODS: We examined 1. the incidence of AD pathology (Braak stageing, CERAD, NIA-Reagan Institute criteria) in 58 consecutive patients (mean age ± SD 77.0 ± 6.8 years) with residual closed TBI lesions, and 2. the frequency of TBI residuals in 57 age-matched autopsy proven AD cases. In both series, ApoE was evaluated from archival paraffin-embedded brain material. RESULTS: 1. TBE series: 12.1 % showed definite and 10.3% probable AD (mean age 77.6 and 75.2 years), only 2/13 with ApoEε3/4. From 45 (77.6%) non-AD cases (mean age 78.2 years), 3 had ApoEε3/4. The prevalence of 22.4% AD in this small autopsy cohort was significantly higher than 3.3% in a recent large clinical series and 14% in the general population over age 70. 2. In the AD cohort with ApoEε4 allele frequency of 30% similar to other AD series, residuals of closed TBI were seen in 4 brains (7%) (mean age ± SD 78.2 ± 6.4), all lacking the ApoEε4 allele. TBI incidence was slightly lower than 8.5% in the clinical MIRAGE study. CONCLUSIONS: The results of this first retrospective autopsy study of TBI, ApoEε allele frequency, and AD confirm clinical studies suggesting severe TBI to be a risk factor for the development AD higher in subjects lacking ApoEε4 alleles. Further studies in larger autopsy series are needed to elucidate the relationship between TBI, genetic predisposition, and AD

TRAIL death receptors DR4 and DR5 mediate cerebral microvascular endothelial cell apoptosis induced by oligomeric Alzheimer's Aβ

Vascular deposition of amyloid-β (Aβ) in sporadic and familial Alzheimer's disease, through poorly understood molecular mechanisms, leads to focal ischemia, alterations in cerebral blood flow, and cerebral micro-/macro-hemorrhages, significantly contributing to cognitive impairment. Here, we show that tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) death receptors DR4 and DR5 specifically mediate oligomeric Aβ induction of extrinsic apoptotic pathways in human microvascular cerebral endothelial cells with activation of both caspase-8 and caspase-9. The caspase-8 inhibitor cellular FLICE-like inhibitory protein (cFLIP) is downregulated, and mitochondrial paths are engaged through BH3-interacting domain death agonist (Bid) cleavage. Upregulation of DR4 and DR5 and colocalization with Aβ at the cell membrane suggests their involvement as initiators of the apoptotic machinery. Direct binding assays using receptor chimeras confirm the specific interaction of oligomeric Aβ with DR4 and DR5 whereas apoptosis protection achieved through RNA silencing of both receptors highlights their active role in downstream apoptotic pathways unveiling new targets for therapeutic intervention

Immunotherapy for Alzheimer's disease and other dementias

Purpose of review: The aim of this article is to review the role of immunotherapy in the removal of proteins which accumulate abnormally in neurodegenerative disorders associated with dementia, in particular amyloid-[beta] accumulation in Alzheimer's disease.Recent findings: In both transgenic mouse models and in two trials of amyloid-[beta] immunotherapy for human Alzheimer's disease, active immunization with amyloid-[beta] 1-42 results in the removal of amyloid-[beta] plaques from the cerebral cortex associated with, in the mouse models, improvement in cognitive function. Cerebral amyloid angiopathy and neurofibrillary tangles persist, however, and there is also concern about T lymphocyte immune reactions in the meninges in the human cases. Active immunization schedules are being developed to minimize T lymphocyte reactions and to maximize antibody production and passive immunization protocols are being devised. Immunotherapy for removal of the proteins which accumulate in other neurodegenerative disorders associated with dementia such as prion proteins and [alpha]-synuclein are in the early stages of development.Summary: Dementias in the elderly are an increasing medical, social and economic problem and current treatments are only effective. In the majority of dementias, proteins accumulate within cells and in the extracellular compartments of the brain. In the most common dementia, Alzheimer's disease, amyloid-[beta] accumulates as plaques in the extracellular space of the grey matter and in artery walls as cerebral amyloid angiopathy and tau protein accumulates as neurofibrillary tangles within neurons

SPINAL-CORD COMPRESSION DUE TO PAGETIC SPINAL STENOSIS WITH INVOLVEMENT OF EXTRADURAL SOFT-TISSUES - A CASE-REPORT

Although Paget's disease of the spine may cause neurological dysfunction by bone hypertrophy or collapse, it is very rare for the disease process to extend into the soft tissues of the spinal canal. We report a case of Paget's disease causing ossification of the ligamentum flavum and extradural fat, thus causing spinal cord compression. Decompressive laminectomy was carried out, resulting in neurological improvement. In such cases surgical decompression should be followed by therapy with calcitonin

Polimorfismo dell'apolipoproteina E nel carcinoma mammario: correlazione con i parametri clinico-patologici e prognosi.

There is preliminary evidence that polymorphism of apolipoprotein E (apoE, protein; APOE, gene), one of the key regulatory proteins in cholesterol metabolism, influences the pathobiology of carcinoma of the colon, prostate and breast and also primary tumours of the brain. This study was designed to determine whether APOE polymorphism is related to variation in the rate of tumour cell proliferation and clinical outcome in carcinoma of the breast. One hundred and eleven infiltrating ductal carcinomas, for which follow up data were available, were included in the study. Estrogen and progesterone receptor status (ER, PR) cell proliferation index (MIB- 1) and APOE genotypes were determined from paraffin-embedded tissue by standard methods. Positive correlations were found between grade and tumour size, grade and presence of metastasis, grade and MIB-1 expression, as well as between ER and PR. Survival correlated inversely with tumour size and the presence of positive lymph nodes. Both steroid receptors correlated inversely with MIB- 1 expression. PR positive status also correlated inversely with high histological grade and presence of lymph node metastases. APOE allele frequencies resembled those of the general population. No significant associations were found between possession of either APOE epsilon2 or epsilon4 alleles and the parameters investigated. Although there is evidence to suggest that APOE epsilon4 may predispose to the development of carcinoma of the breast our data do not support the hypothesis that APOE genotype influences the rate of tumour cell proliferation or the clinical course