Neuropathology of the hippocampus in FTLD-Tau with Pick bodies: a study of the BrainNet Europe Consortium.

AIMS: Frontotemporal lobar degeneration with Pick bodies (Pick's disease) is characterized by the presence of tau immunoreactive spherical structures in the cytoplasm of neurones. In view of confusion about the molecular pathology of Pick's disease, we aimed to evaluate the spectrum of tau pathology and concomitant neurodegeneration-associated protein depositions in the characteristically affected hippocampus. METHODS: We evaluated immunoreactivity (IR) for tau (AT8, 3R, 4R), α-synuclein, TDP43, p62, and ubiquitin in the hippocampus, entorhinal and temporal cortex in 66 archival cases diagnosed neuropathologically as Pick's disease. RESULTS: Mean age at death was 68.2 years (range 49-96). Fifty-two (79%) brains showed 3R immunoreactive spherical inclusions in the granule cells of the dentate gyrus. These typical cases presented mainly with the behavioural variant of frontotemporal dementia, followed by progressive aphasia, mixed syndromes or early memory disturbance. α-Synuclein IR was seen only in occasional spherical tau-positive inclusions, TDP-43 IR was absent, and 4R IR was present only as neurofibrillary tangles in pyramidal neurones. Aß IR was observed in 16 cases; however, the overall level of Alzheimer's disease-related alterations was mainly low or intermediate (n = 3). Furthermore, we identified six cases with unclassifiable tauopathy. CONCLUSIONS: (i) Pick's disease may occur also in elderly patients and is characterized by a relatively uniform pathology with 3R tau inclusions particularly in the granule cells of dentate gyrus; (ii) even minor deviation from these morphological criteria suggests a different disorder; and (iii) immunohistological revision of archival cases expands the spectrum of tauopathies that require further classification.

Magnetic resonance imaging of fixed post mortem brains reliably reflects subcortical vascular pathology of frontal, parietal and occipital white matter.

AIMS: Subcortical vascular pathology of the white and deep grey matter (WM and DGM) is associated with cognitive impairment. Routine neuropathological assessment of subcortical vascular pathology is based on semiquantitative scoring of characteristic lesions in a limited number of histological slides from selected WM and DGM areas. Clinically, WM and DGM lesions are visualized as hyper-intensities on magnetic resonance imaging (MRI). The aim of this study was to evaluate the feasibility of MRI on fixed post mortem brain hemispheres to complement routine neuropathological assessment of subcortical vascular pathology. METHODS: We assessed subcortical vascular pathology in 40 post mortem brain hemispheres from demented (n = 26) and nondemented (n = 14) individuals (mean age 83.2 ± 14.8 years; 62.5% female) using (i) routine histological assessment; (ii) extensive histological assessment of the entire hemisphere at 7-mm intervals; and (iii) full T2-weighted MRI performed on fixed post mortem brain hemispheres. RESULTS: In both WM and DGM routine histological scores for subcortical vascular pathology were significantly lower (P < 0.01) than the corresponding scores obtained by extensive histological assessment. In contrast, no significant differences were seen between scores obtained by MRI and extensive histological assessment in frontal, parietal and occipital lobes while MRI scores were significantly lower in the temporal WM and DGM (P < 0.01). CONCLUSIONS: The results of our study indicate that routine histological assessment underrates subcortical vascular pathology and we conclude that MRI could be used in addition to complement neuropathological post mortem assessment of subcortical vascular pathology of the WM.

[HTLV-1-associated myelopathy/tropical spastic paraparesis: a differential diagnosis in multiple sclerosis]. / HTLV-1-assoziierte Myelopathie/tropische spastische Paraparese : Eine Differenzialdiagnose der Multiplen Sklerose.

Human T-cell lymphotropic virus 1 (HTLV-1) associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a neurological disease caused by infection with HTLV-1. The disorder is very rare in Europe but endemic in many parts of the world. The pathogenesis is not clearly characterized but is based on a possibly immune-mediated injury of the cervicothoracic spinal cord. Clinically, HAM/TSP constitutes a slowly progressive spastic paraparesis associated with bladder dysfunction and often mimics the course of autoimmune and neurodegenerative diseases. The diagnosis is based on typical symptoms as well as detection of HTLV-1 specific antibodies and proviral HTLV-1 DNA or HTLV-1 RNA. The therapy is limited to symptomatic treatment. Transmission of HTLV-1 can occur vertically by breast feeding, through sexual contact or via infected blood products. Based on a clinical case report, we present here a current review on the pathophysiology, epidemiology, clinical manifestations, diagnosis and treatment of HAM/TSP.

Cerebral subcortical small vessel disease and its relation to cognition in elderly subjects: a pathological study in the Oxford Project to Investigate Memory and Ageing (OPTIMA) cohort.

BACKGROUND: Subcortical small vessel disease (SVD) is known to contribute to vascular cognitive impairment and vascular dementia, but understanding about the extent of its influence is limited because there is a lack of consensus about how this pathology should be assessed. METHODS: In this study we have made use of a simple, novel, image-matching scoring system to assess the extent of SVD in a group of 70 cases from the prospectively assessed Oxford Project to Investigate Memory and Ageing (OPTIMA) cohort. These cases were found at autopsy to have cerebrovascular disease and no other pathology except Braak stage 4 or less tau pathology, and insufficient amyloid plaque pathology to meet Consortium to Establish a Registry for Alzheimer's Disease (CERAD) criteria for the diagnosis of Alzheimer's disease. Pathology scores for SVD were correlated with cognitive scores [Mini-Mental State Examination (MMSE) and cognitive section of the Cambridge Examination for Mental Disorders in the Elderly (CAMDEX) (CAMCOG)] at the last clinical assessment before death. RESULTS: The severity of SVD pathology was inversely related to cognitive score before death (P < 0.008 for MMSE and P < 0.024 for CAMCOG). Thirty-one per cent and 33% of cases were rated as demented by MMSE or CAMCOG respectively. The degree of dementia was generally mild. Age did not influence severity of SVD. CONCLUSIONS: An image-based scoring system for SVD in a group of 70 elderly subjects enabled the severity of SVD pathology to be assessed with results that showed a significant correlation between SVD pathology severity and cognitive impairment.

Neuropathologic evidence of endothelial changes in cerebral small vessel disease.

OBJECTIVES: Cerebral small vessel disease (SVD) is common in aged brains and causes lacunar stroke, diffuse white matter lesions (leukoaraiosis), and vascular cognitive impairment. The pathogenesis is unknown. Endothelial dysfunction is a possible causal factor, and circulating markers of endothelial activation (intercellular adhesion molecule-1, thrombomodulin) and inflammation (interleukin [IL]-6) are elevated in patients with SVD. In this case-control study, we tested whether brain endothelial ICAM1, thrombomodulin, and IL-6 are altered in SVD. METHODS: We examined small penetrating cerebral arteries of pathologically diagnosed SVD cases, aged controls without SVD, young control cases with no brain pathology, and cases with early-onset hereditary SVD (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy [CADASIL]). All tissues had minimal cerebral amyloid angiopathy or other Alzheimer pathology. RESULTS: Thrombomodulin immunoreactivity was present in all aged SVD, aged control, and CADASIL cases, primarily in small artery endothelium. Thrombomodulin was augmented in aged SVD cases compared with aged controls (p = 0.012) and in vessels with higher sclerotic index (an indicator of SVD severity; p < 0.01). Thrombomodulin was sparse/absent in young controls. Endothelial ICAM1 and IL-6 were rarely seen, and were not related to SVD. CONCLUSIONS: Our data suggest that cerebral endothelial activation in deep penetrating arteries is not associated with SVD. Endothelial thrombomodulin increased with SVD severity, and CADASIL data suggest that this may be a cerebral response to SVD. Elevated thrombomodulin may be a protective agent in SVD. Our data confirm endothelial involvement in SVD.

Focal and diffuse cortical degenerative changes in a marmoset model of multiple sclerosis.

BACKGROUND: Degenerative features, such as neuronal, glial, synaptic and axonal loss, have been identified in neocortical and other grey matter structures in patients with multiple sclerosis, but mechanisms for neurodegeneration are unclear. Cortical demyelinating lesions are a potential cause of this degeneration, but the pathological and clinical significance of these lesions is uncertain as they remain difficult to identify and study in vivo. In this study we aimed to describe and quantify cellular and subcellular pathology in the cortex of myelin oligodendrocyte glycoprotein-induced marmoset experimental autoimmune encephalomyelitis using quantitative immunohistochemical methods. RESULTS: We found evidence of diffuse axonal damage occurring throughout cortical grey matter with evidence for synaptic loss and gliosis and a 13.6% decrease in neuronal size and occurring in deep cortical layers. Evidence of additional axonal damage and a 29.6-36.5% loss of oligodendrocytes was found in demyelinated cortical lesions. Leucocortical lesions also showed neuronal loss of 22.2% and a 15.8% increase in oligodendrocyte size. CONCLUSIONS: The marmoset experimental autoimmune encephalomyelitis model, therefore, shows both focal and generalized neurodegeneration. The generalized changes cannot be directly related to focal lesions, suggesting that they are either a consequence of diffusible inflammatory factors or secondary to remote lesions acting through trans-synaptic or retrograde degeneration.

MS: is it one disease?

Understanding the molecular pathology of multiple sclerosis (MS) is crucial to interpretation of magnetic resonance imaging appearances in the disease and to developing new therapies. The pathology of MS has always been recognized to be heterogeneous, with the basis of this heterogeneity being hitherto largely attributed to differences in the age of lesions. However, one influential group of researchers put forward the suggestion in 2000 that there are four pathological subtypes of MS that are distinct between cases but consistent within cases. Two more recent attempts to replicate this finding have been unsuccessful, as reviewed by Barnett et al. (this issue, pages 57 to 65). This inability to confirm pathological disease subtypes within the MS disease spectrum is in contrast to recent work on neuromyelitis optica--until recently regarded as part of the MS spectrum--in which evidence from a variety of sources has led to the rapid, widespread acceptance that this condition is indeed distinct from MS. It is important to resolve the outstanding controversies in MS immunopathology and one way to do this might be to conduct a consensus study, a method that has proved valuable in bringing better consistency to the reporting of Alzheimers disease pathology.

Symptomatic, radiological and pathological involvement of the hypothalamus in neuromyelitis optica.

This study describes a young girl who presented with involuntary weight loss, spontaneous vomiting and behavioural change. Imaging confirmed hypothalamic and brainstem involvement. Routine investigations (including cerebrospinal fluid analysis and neuromyelitis optica IgG) were unhelpful. Biopsy of the hypothalamic lesion implicated an aggressive inflammatory aetiology. There was a response to conventional immunosuppression, while a further relapse responded to plasma exchange. She died 21 months after presentation. Postmortem examination was highly suggestive of neuromyelitis optica, which was subsequently confirmed following the identification of aquaporin 4 antibodies.

Loss of [3H]4-DAMP binding to muscarinic receptors in the orbitofrontal cortex of Alzheimer's disease patients with psychosis.

RATIONALE: Neuropsychiatric behaviours in Alzheimer's disease (AD) patients have been associated with neocortical alterations of presynaptic cholinergic and muscarinic M2 receptor markers. In contrast, it is unclear whether non-M2 muscarinic receptors have a role to play in AD behavioural symptoms. OBJECTIVES: To correlate the alterations of neocortical postsynaptic muscarinic receptors with clinical features of AD. MATERIALS AND METHODS: [(3)H]4-DAMP were used in binding assays with lysates of Chinese hamster ovary (CHO) cells stably transfected with M1-M5 receptors. [(3)H]4-DAMP was further used to measure muscarinic receptors in the postmortem orbitofrontal cortex of aged controls and AD patients longitudinally assessed for cognitive decline and behavioural symptoms. RESULTS: [(3)H]4-DAMP binds to human postmortem brain homogenates and M1-, M3-, M4- and M5-transfected CHO lysates with subnanomolar affinity. Compared to the controls, the [(3)H]4-DAMP binding density is reduced only in AD patients with significant psychotic symptoms. The association between reduced [(3)H]4-DAMP binding and psychosis is independent of the effects of dementia severity or neurofibrillary tangle burden. CONCLUSIONS: This study suggests that the loss of non-M2 muscarinic receptors in the orbitofrontal cortex may be a neurochemical substrate of psychosis in AD and provides a rationale for further development of muscarinic receptor ligands in AD pharmacotherapy.

LRRK2 is a component of granular alpha-synuclein pathology in the brainstem of Parkinson's disease.

Classical Parkinson's disease (PD) is characterized by the appearance of Lewy bodies (LBs) in affected brain regions, showing mostly compact alpha-synuclein deposition, in contrast with punctate or granular deposition, hypothesized to represent early stages of aggregation. Leucine-rich repeat kinase 2 (LRRK2) is the commonest mutated gene in inherited and idiopathic PD. LRRK2 mutation carriers display a diverse neuropathology, including alpha-synuclein and tau inclusions, suggesting an upstream role for LRRK2 in protein aggregation. We studied LRRK2 expression throughout the normal human brain with three different antibodies. We also examined the pattern of LRRK2 expression in relation to alpha-synuclein aggregation and LB formation in the brainstem of sporadic LB disease. Physiological LRRK2 expression was not restricted to regions preferentially affected in PD and LRRK2 often localized to the nuclear envelope in addition to the known cytoplasmic expression. In PD, we were able to consistently detect LRRK2 in the halo of a minority (approximately 10%) of nigral LBs using three different antibodies. Only one antibody detected LRRK2 in the core of approximately 80% of classic LBs. In the lower brainstem, most notably in the dorsal motor nucleus of the vagus, we found previously unrecognized LRRK2 labelling of complex globular lesions, filled with LB-like matter showing a punctate or granular staining for alpha-synuclein. This was often accompanied by strong LRRK2 expression within dystrophic neurites. Our findings confirm widespread physiological LRRK2 expression in the human brain and suggest an association of LRRK2 with possible early-stage alpha-synuclein pathology in the brainstem of PD.

Imbalance of a serotonergic system in frontotemporal dementia: implication for pharmacotherapy.

RATIONALE: Information is sparse on neurotransmitter deficiencies in frontotemporal dementia (FTD), in particular with reference to distinct histological subgroups and Alzheimer's disease (AD). OBJECTIVES: To evaluate in FTD with the major histologies, and compare with AD and controls, neurotransmission indices, as these may help in developing treatment. MATERIALS AND METHODS: Post-mortem grey matter from Brodmann Area 21, 9 and 7 of 51 brains was assayed for ten neurochemical parameters indexing neurotransmission. Repeated measures analyses of variance were carried out for each parameter comparing groups (FTD vs AD vs control) at each anatomical site. RESULTS: In FTD only the indices of alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid, serotonin (5-HT)(1A) and 5-HT(2A) receptors were significantly reduced from control values. Of the ten parameters only 5-HT(1A) receptors showed significant group x site interaction. This reflected disproportionate reduction in frontal and temporal compared to parietal cortex. In FTD three other receptors (muscarinic, M(1), N-methyl-D: -aspartate, NMDA, and kainate), choline acetyltransferase (ChAT) activity, 5-HT and 5-hydroxyindoleacetic acid content and 5-HT reuptake site values were not significantly reduced from control values. Only 5-HT, 5-HT reuptake site and ChAT values were significantly higher in FTD than AD. NMDA receptor and ChAT values were significantly reduced from control only in AD. CONCLUSIONS: Neurochemical results in FTD indicate degeneration and loss of pyramidal neurones in frontotemporal neocortex, yet 5-HT afferents and 5-HT concentration, which are inhibitory on pyramidal neurones, were relatively preserved. This could lead to an excess of extraneural 5-HT causing underactivity of surviving pyramidal neurones. Pharmacotherapy with a 5-HT(1A) receptor antagonist may be indicated.

Cerebral calpain in fatal falciparum malaria.

Disruption of axonal transport may represent a final common pathway leading to neurological dysfunction in cerebral malaria (CM). Calpains are calcium (Ca2+)-activated cysteine proteases which have been implicated in axonal injury in neurological diseases of various aetiologies. In this study we examined the association between mu- and m-calpain, the specific inhibitor calpastatin, and axonal injury in post mortem brain tissue from patients who died from severe malaria. Calpains were associated with axons labelled for the beta-amyloid precursor protein that detects impaired axonal transport. Elevated levels of calpastatin were rarely observed in injured axons. There were increased numbers of neurones with mu-calpain in the nuclear compartment in severe malaria cases compared with non-neurological controls, and increased numbers of glia with nuclear mu-calpain in CM patients compared with non-CM malaria cases and non-neurological controls. There was marked redistribution of calpastatin in the sequestered Plasmodium falciparum-infected erythrocytes. Responses specific to malaria infection were ascertained following analysis of brain samples from fatal cases with acute axonal injury, HIV encephalitis, and progressive multifocal leucoencephalopathy. Our findings implicate a role for calpains in the modulation of disease progression in CM.

Ageing and the brain.

In this review, the evidence for changes in the human brain with ageing at both the macroscopic and microscopic levels is summarized. Loss of neurons is now recognized to be more modest than initial studies suggested and only affects some neuron populations. Accompanying loss of neurons is some reduction in the size of remaining neurons. This reflects a reduced size of dendritic and axonal arborizations. Some of the likely causes of these changes, including free radical damage resulting from a high rate of oxidative metabolism in neurons, glycation and dysregulation of intracellular calcium homeostasis, are discussed. The roles of genes and environmental factors in causing and responding to ageing changes are explored.

Neocortical neuronal, synaptic, and glial loss in multiple sclerosis.

BACKGROUND: Recent pathologic investigations have shown that neocortical lesions are frequent in multiple sclerosis (MS). Structural MRI has shown that neocortical atrophy occurs early and can be substantial, but the specific substrate for this atrophy has not been defined quantitatively. OBJECTIVE: To investigate cortical thickness as well as neuronal, glial, and synaptic densities in MS. METHODS: We studied brain samples from 22 patients with MS and 17 control subjects. Neocortical lesions and cortical thickness were assessed on sections stained for myelin basic protein. Neuronal, glial, and synaptic densities were measured in type I leukocortical lesions, nonlesional neocortex, and non-MS control cortex. Immunoautoradiography was used to quantify synaptic densities. RESULTS: Neocortical lesions were common in patients with MS. Subpial type III (44%) and leukocortical type I (38%) lesions were more abundant than intracortical type II (18%) lesions. An overall relative neocortical thinning of 10% (p = 0.016) was estimated for the patients. Within the type I lesions, we found evidence for substantial cell (glial, 36%, p = 0.001; neuronal, 10%, p = 0.032) and synaptic (47% decrease in synaptophysin, p = 0.001) loss. Nonlesional neocortex did not show significant relative changes in neuronal, glial, or synaptic density. CONCLUSIONS: Neocortical neuronal and glial degeneration is significant in multiple sclerosis. Synaptic loss was particularly striking in the neocortical lesions, which should make a major independent contribution to the expression of pathology. New therapies should be directed toward limiting this damage.

Vulnerability to Alzheimer's pathology in neocortex: the roles of plasticity and columnar organization.

Two principal findings in the Pearson et al. paper are commented on here. The first is the regional selectivity within the cerebrum of neurofibrillary tangle (NFT) formation in Alzheimer's disease (AD) which targets association cortex and the primary olfactory cortex alone among regions of primary sensory cortex. The second finding is the clustering of NFT in columns of supra- and infra-granular layers of association cortex. We review recent evidence confirming these findings and comment on their possible significance. We consider that the most attractive hypothesis to explain the vulnerability of the olfactory system and association cortex is the persistent neural plasticity of these regions. On this basis there would be no need to postulate a progressive spreading process. The columnar distribution of clustered NFT can be well understood in the context of recent concepts of columnar organization of the cerebral cortex. The original interpretation that this distribution of NFT reflects pathology in neurons subserving cortico-cortical and cortico-subcortical connections seems to us to have stood the test of time.

The contribution of demyelination to axonal loss in multiple sclerosis.

The traditional notion that multiple sclerosis is a primary demyelinating disease has led to a plaque-centred view of both aetiology and the pathogenesis of disease progression. The presence of axonal loss has received increasing recognition. However, the relative roles of demyelination and axonal loss have not been fully clarified in multiple sclerosis nor have their possible interrelationships been elucidated. Post-mortem material from the cerebrum, brainstem and spinal cord of 55 multiple sclerosis patients (29 males) with an age range of 25-83 years (mean = 57.5 years) and length of disease history ranging from 2 to 43 years (mean = 17.1 years) was stained for myelin. Plaque load was calculated by summing the relative proportion of plaque area compared with total white matter area of the corticospinal and sensory tracts at each level. This was related to estimates of axonal density and of total axon number in these tracts in the spinal cord. Our results indicate that plaque load did not correlate with brain weight. Unexpectedly, after adjusting for sex, age and duration of disease, correlations between total plaque load and axonal loss in both the corticospinal tract and sensory tracts were weak or absent at each level investigated. Since there was little correlation between plaque load and axonal loss, the possibility that demyelination is not the primary determinant of spinal cord axonal loss warrants consideration.

Severe cerebral congophilic angiopathy coincident with increased brain aluminium in a resident of Camelford, Cornwall, UK.

In July 1988, 20 tonnes of aluminium sulphate was discharged by the South West Water Authority into the drinking water supplied to a large region of North Cornwall. Up to 20,000 people were exposed to concentrations of aluminium which were 500-3000 times the acceptable limit under European Union legislation (0.200 mg/l). Although this incident is currently the topic of a government inquiry, nothing is known about its longer-term repercussions on human health. The first neuropathological examination of a person who was exposed and died of an unspecified neurological condition was carried out. A rare form of sporadic early-onset beta amyloid angiopathy in cerebral cortical and leptomeningeal vessels, and in leptomeningeal vessels over the cerebellum was identified. In addition, high concentrations of aluminium were found coincident with the severely affected regions of the cortex. Although the presence of aluminium is highly unlikely to be adventitious, determining its role in the observed neuropathology is impossible. A clearer understanding of aluminium's role in this rare form of Alzheimer's related disease should be provided by future research on other people from the exposed population as well as similar neuropathologies in people within or outside this group.

Depression in the elderly: pathological study of raphe and locus ceruleus.

Depressive symptoms in the elderly are common and disabling and constitute a risk factor for the development of Alzheimer's disease (AD). One hypothesis worth exploring is that depression in the elderly is related to development of AD pathology at subcortical sites before such pathology develops in the hippocampus and neocortex. We describe here an autopsy study of the locus ceruleus (LC) and raphe nuclei (RN) in nine subjects with depression and 18 age and sex matched controls that were included in a community-based study of cognitive function and ageing (MRC-CFAS). We found no relationship between depression and (1) mean counts of serotonergic or total RN neuronal profiles (2) noradrenergic or total LC neuronal profiles (3) counts of neurofibrillary tangles in these nuclei, or (4) size of neurones in the RN. Nor were these parameters related to age or sex of the subjects. We conclude that depression in the elderly is unlikely to be related to RN or LC neurone counts or RN cell size or to AD-type pathology in these nuclei. However, because of the small numbers of cases studied and our inability to carry out a full stereological study because of tissue limitations the findings are preliminary.

The dorsal raphe nucleus in schizophrenia: a post mortem study of 5-hydroxytryptamine neurones.

The 5-hydroxytryptamine (5-HT, serotonin) system has been implicated in the pathophysiology and treatment of schizophrenia. In this study, we addressed the hypothesis that a deficit of 5-HT neurones, either inherited or acquired, is central to the developmental pathology of the disorder. We examined putative 5-HT neurones of the dorsal raphe nucleus (DRN) in post mortem, formalin-fixed tissue from 15 schizophrenic patients and 20 control subjects matched for age and gender. No significant difference was detected between these groups in the number or size (cross-sectional area or diameter) of tryptophan-hydroxylase-immunoreactive cell profiles viewed in transverse sections collected from the level of the trochlear decussation to the emergence of the trigeminal nerve. Profile number was not affected by age, gender, side of the brainstem (left or right) or post mortem interval; however, time in formalin correlated negatively with the number of neurones counted. Moreover, a significant negative correlation was detected between time in formalin and the levels of immunoreaction product (optical density), which in turn correlated positively with our profile counts. A positive correlation was found between the age of subjects and our estimates of cell size. Our results do not support the proposal that an abnormality in the number and/or size of DRN 5-HT neurones is central to the aetiopathology of schizophrenia.