104 research outputs found

    Pro: Can neuropathology really confirm the exact diagnosis?

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    Recent advances in the clinical diagnostic instruments for diagnosing Alzheimer's disease (AD) and in neuroimaging may cast doubt in the minds of some practitioners about the continued need for neuropathology to provide the ultimate diagnosis. Certainly the majority of cases of AD can be clinically correctly diagnosed by experienced clinicians but many cases are given this label by less experienced practitioners. Even after the most thorough work-up, a few cases of confidently diagnosed AD turn out to be something else when microscopy of the brain is undertaken. Even for neuropathologists, however, it can be difficult to correctly assign cognitive decline to the various pathological processes that can be found together in an older brain. We need further clinicopathogical study to enlighten us about, for example, the contribution of commonly found cerebrovascular disease to dementia. Human studies are also needed to explore the changes in pathology that new treatments for AD may produce

    Complement and humoral adaptive immunity in the human choroid plexus: roles for stromal concretions, basement membranes, and epithelium

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    The choroid plexus (CP) provides a barrier to entry of toxic molecules from the blood into the brain and transports vital molecules into the cerebrospinal fluid. While a great deal is known about CP physiology, relatively little is known about its immunology. Here, we show immunohistochemical data that help define the role of the CP in innate and adaptive humoral immunity. The results show that complement, in the form of C1q, C3d, C9, or C9neo, is preferentially deposited in stromal concretions. In contrast, immunoglobulin (Ig) G (IgG) and IgA are more often found in CP epithelial cells, and IgM is found in either locale. C4d, IgD, and IgE are rarely, if ever, seen in the CP. In multiple sclerosis CP, basement membrane C9 or stromal IgA patterns were common but were not specific for the disease. These findings indicate that the CP may orchestrate the clearance of complement, particularly by deposition in its concretions, IgA and IgG preferentially via its epithelium, and IgM by either mechanism

    IL-21 and IL-21 Receptor Expression in Lymphocytes and Neurons in Multiple Sclerosis Brain

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    IL-17–producing CD4+ T cells (Th-17) contribute to the pathogenesis of experimental autoimmune encephalomyelitis and are associated with active disease in multiple sclerosis (MS). In addition to IL-17, Th-17 cells can also express IL-21, IL-22, and IL-6 under Th-17–polarizing conditions (IL-6 and transforming growth factor-β). In this study we investigated IL-21 and IL-21 receptor (IL-21R) expression in MS lesions by in situ hybridization and immunohistochemistry. We detected strongly IL-21+ infiltrating cells predominantly in acute but also in chronic active white matter MS lesions in which IL-21 expression was restricted to CD4+ cells. In contrast, IL-21R was much more broadly distributed on CD4+, CD19+, and CD8+ lymphocytes but not major histocompatibility complex class-II+ macrophages/microglia. Interestingly, in cortical areas we detected both IL-21 and IL-21R expression by neurons. These findings suggest role(s) for IL-21 in both the acute and chronic stages of MS via direct effects on T and B lymphocytes and, demonstrated for the first time, also on neurons

    Evidence for a novel neuronal mechanism driving Alzheimer's disease, upstream of amyloid

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    This perspective offers an alternative to the amyloid hypothesis in the etiology of Alzheimer's disease (AD). We review evidence for a novel signaling mechanism based on a little‐known peptide, T14. T14 could drive neurodegeneration as an aberrantly activated process of plasticity selective to interconnecting subcortical nuclei, the isodendritic core, where cell loss starts at the pre‐symptomatic stages of the disease. Each of these cell groups has the capacity to form T14, which can stimulate production of p‐Tau and β‐amyloid, suggestive of an upstream driver of neurodegeneration. Moreover, results in an animal AD model show that antagonism of T14 with a cyclated variant, NBP14, prevents formation of β‐amyloid, and restores cognitive function to that of wild‐type counterparts. Any diagnostic and/or therapeutic strategy based on T14‐NBP14 awaits validation in clinical trials. However, an understanding of this novel signaling system could bring much‐needed fresh insights into the progression of cell loss underlying AD. Highlights: The possible primary mechanism of neurodegeneration upstream of amyloid. Primary involvement of selectively vulnerable subcortical nuclei, isodendritic core. Bioactive peptide T14 trophic in development but toxic in context of mature brain. Potential for early‐stage biomarker to detect Alzheimer's disease. Effective therapeutic halting neurodegeneration, validated already in 5XFAD mice

    Cases, Regulations, and Statutes

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    With the exception of ApoE4, genome-wide association studies have failed to identify strong genetic risk factors for late-onset Alzheimer's disease, despite strong evidence of heritability, suggesting that many low penetrance genes may be involved. Additionally, the nature of the identified genetic risk factors and their relation to disease pathology is also largely obscure. Previous studies have found that a cancer-associated variant of the cell cycle inhibitor gene p21cip1 is associated with increased risk of Alzheimer's disease. The aim of this study was to confirm this association and to elucidate the effects of the variant on protein function and Alzheimer-type pathology. We examined the association of the p21cip1 variant with Alzheimer's disease and Parkinson's disease with dementia. The genotyping studies were performed on 719 participants of the Oxford Project to Investigate Memory and Ageing, 225 participants of a Parkinson's disease DNA bank, and 477 participants of the Human Random Control collection available from the European Collection of Cell Cultures. The post mortem studies were carried out on 190 participants. In the in-vitro study, human embryonic kidney cells were transfected with either the common or rare p21cip1 variant; and cytometry was used to assess cell cycle kinetics, p21cip1 protein expression and sub-cellular localisation. The variant was associated with an increased risk of Alzheimer's disease, and Parkinson's disease with dementia, relative to age matched controls. Furthermore, the variant was associated with an earlier age of onset of Alzheimer's disease, and a more severe phenotype, with a primary influence on the accumulation of tangle pathology. In the in-vitro study, we found that the SNPs reduced the cell cycle inhibitory and anti-apoptotic activity of p21cip1. The results suggest that the cancer-associated variant of p21cip1 may contribute to the loss of cell cycle control in neurons that may lead to Alzheimer-type neurodegeneration

    Concurrent multiple sclerosis and amyotrophic lateral sclerosis: where inflammation and neurodegeneration meet?

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    The concurrence of multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS) is exceedingly rare and the pathological features have not been examined extensively. Here we describe the key pathological features of a 40 year old man with pathologically confirmed concurrent MS and ALS

    A role for vessel‐associated extracellular matrix proteins in multiple sclerosis pathology

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    Multiple sclerosis (MS) is unsurpassed for its clinical and pathological hetherogeneity, but the biological determinants of this variability are unknown. HLA‐DRB1*15, the main genetic risk factor for MS, influences the severity and distribution of MS pathology. This study set out to unravel the molecular determinants of the heterogeneity of MS pathology in relation to HLA‐DRB1*15 status. Shotgun proteomics from a discovery cohort of MS spinal cord samples segregated by HLA‐DRB*15 status revealed overexpression of the extracellular matrix (ECM) proteins, biglycan, decorin, and prolargin in HLA‐DRB*15‐positive cases, adding to established literature on a role of ECM proteins in MS pathology that has heretofore lacked systematic pathological validation. These findings informed a neuropathological characterisation of these proteins in a large autopsy cohort of 41 MS cases (18 HLA‐DRB1*15‐positive and 23 HLA‐DRB1*15‐negative), and seven non‐neurological controls on motor cortical, cervical and lumbar spinal cord tissue. Biglycan and decorin demonstrate a striking perivascular expression pattern in controls that is reduced in MS (−36.5%, p = 0.036 and − 24.7%, p = 0.039; respectively) in lesional and non‐lesional areas. A concomitant increase in diffuse parenchymal accumulation of biglycan and decorin is seen in MS (p = 0.015 and p = 0.001, respectively), particularly in HLA‐DRB1*15‐positive cases (p = 0.007 and p = 0.046, respectively). Prolargin shows a faint parenchymal pattern in controls that is markedly increased in MS cases where a perivascular deposition pattern is observed (motor cortex +97.5%, p = 0.001; cervical cord +49.1%, p = 0.016). Our findings point to ECM proteins and the vascular interface playing a central role in MS pathology within and outside the plaque area. As ECM proteins are known potent pro‐inflammatory molecules, their parenchymal accumulation may contribute to disease severity. This study brings to light novel factors that may contribute to the heterogeneity of the topographical variation of MS pathology

    Alpha-synuclein RT-QuIC in the CSF of patients with alpha-synucleinopathies

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    We have developed a novel real-time quaking-induced conversion RT-QuICbased assay to detect alpha-synuclein aggregation in brain and cerebrospinal fluid from dementia with Lewy bodies and Parkinson’s disease patients. This assay can detect alpha-synuclein aggregation in Dementia with Lewy bodies and Parkinson’s disease cerebrospinal fluid with sensitivities of 92% and 95%, respectively, and with an overall specificity of 100% when compared to Alzheimer and control cerebrospinal fluid. Patients with neuropathologically confirmed tauopathies (progressive supranuclear palsy; corticobasal degeneration) gave negative results. These results suggest that RT-QuiC analysis of cerebrospinal fluid is potentially useful for the early clinical assessment of patients with alpha-synucleinopathies

    Age-dependent expression of VEGFR2 in deep brain arteries in small vessel disease, CADASIL, and healthy brains

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    Vascular myocytes are central to brain aging. Small vessel disease (SVD; arteriolosclerosis) is a widespread cause of lacunar stroke and vascular dementia, and is characterised by fibrosis and depletion of vascular myocytes in small penetrating arteries. Vascular endothelial growth factor (VEGF) is associated with brain aging, and VEGFR2 is a potent determinant of cell fate. Here, we tested whether VEGFR2 in vascular myocytes is associated with older age and SVD in human brain. VEGFR2 immunolabelling in deep grey matter was assessed in older people with or without moderate-severe SVD, or in younger people without brain pathology or with a monogenic form of SVD (CADASIL). All cases were without Alzheimer’s disease pathology. Myocyte VEGFR2 was associated with increasing age (p=0.0026) but not with SVD pathology or with sclerotic index or blood vessel density. We conclude that VEGFR2 is consistently expressed in small artery myocytes of older people, and may mediate effects of VEGF on brain vascular aging

    Immunohistochemical study of N-epsilon-carboxymethyl lysine (CML) in human brain: relation to vascular dementia

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    <p>Abstract</p> <p>Background</p> <p>Advanced glycation end-products (AGEs) and their receptor (RAGE) occur in dementia of the Alzheimer's type and diabetic microvascular disease. Accumulation of AGEs relates to risk factors for vascular dementia with ageing, including hypertension and diabetes. Cognitive dysfunction in vascular dementia may relate to microvascular disease resembling that in diabetes. We tested if, among people with cerebrovascular disease, (1) those with dementia have higher levels of neuronal and vascular AGEs and (2) if cognitive dysfunction depends on neuronal and/or vascular AGE levels.</p> <p>Methods</p> <p>Brain Sections from 25 cases of the OPTIMA (Oxford Project to Investigate Memory and Ageing) cohort, with varying degrees of cerebrovascular pathology and cognitive dysfunction (but only minimal Alzheimer type pathology) were immunostained for N<sup><it>ε</it></sup>-(carboxymethyl)-lysine (CML), the most abundant AGE. The level of staining in vessels and neurons in the cortex, white matter and basal ganglia was compared to neuropsychological and other clinical measures.</p> <p>Results</p> <p>The probability of cortical neurons staining positive for CML was higher in cases with worse cognition (p = 0.01) or a history of hypertension (p = 0.028). Additionally, vascular CML staining related to cognitive impairment (p = 0.02) and a history of diabetes (p = 0.007). Neuronal CML staining in the basal ganglia related to a history of hypertension (p = 0.002).</p> <p>Conclusion</p> <p>CML staining in cortical neurons and cerebral vessels is related to the severity of cognitive impairment in people with cerebrovascular disease and only minimal Alzheimer pathology. These findings support the possibility that cerebral accumulation of AGEs may contribute to dementia in people with cerebrovascular disease.</p
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