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.

Unclassifiable tauopathy associated with an A152T variation in MAPT exon 7.

Mutations in the microtubule-associated tau (MAPT) gene are associated clinically with frontotemporal dementia with or without supranuclear palsy, corticobasal syndrome or parkinsonism. Here we present clinical, neuropathological, genetic and biochemical data on a patient with an A152T variation in exon 7 of MAPT. A 63-year-old man presented with memory disturbance and later speech disorder, followed by progressive dementia and terminally myoclonus together with periodic sharp waves in EEG. Duration of illness was 5 years. Similar neuropsychiatric symptoms were reported in the patient's father. Neuropathological evaluation revealed neuronal loss mainly in the frontal and temporal cortices and substantia nigra. Abundant phospho-tau immunoreactive thread-like structures and diffuse staining of neuronal cytoplasm predominated in the frontal and temporal cortex, and hippocampus. There was a lack of astrocytic plaques and tufted astrocytes, and only a moderate number of oligodendroglial coiled bodies were seen. Tau pathology was characterized by the 4R tau isoform; immunoblot revealed bands at 64 and 68 kDa, and ultrastructure of filaments was compatible with twisted ribbons. Pathogenic mutations have not been reported in exon 7. Our observation of an apparently familial disorder with a novel neuropathological phenotype suggests a possible pathogenic role of this MAPT gene variation, which might be different from mutations affecting the microtubule binding.

Multiple intracranial cavernomas with focal amyloid deposition - diagnostic pitfalls.

We report a case of a patient with multiple, intracranial superficial calcified tumorous lesions with focal amyloid deposition. On the basis of the first neuronavigated needle biopsy, the tumors were originally assessed as amyloidomas. Additional data was obtained from a second biopsy and supplementary neuroimaging information and the tumors were diagnosed as of vascular origin, probably cavernomas. The report exemplifies how only one diagnostic tool may sometimes be misleading in establishing a final diagnosis. The additional imaging may thoroughly enhance, supplement and improve the diagnostic process.

Viral meningoencephalitis: a review of diagnostic methods and guidelines for management.

BACKGROUND: Viral encephalitis is a medical emergency. The prognosis depends mainly on the pathogen and host immunologic state. Correct immediate diagnosis and introduction of symptomatic and specific therapy has a dramatic influence upon survival and reduces the extent of permanent brain injury. METHODS: We searched the literature from 1966 to 2009. Recommendations were reached by consensus. Where there was lack of evidence but consensus was clear, we have stated our opinion as good practice points. RECOMMENDATIONS: Diagnosis should be based on medical history and examination followed by CSF analysis for protein and glucose levels, cellular analysis, and identification of the pathogen by polymerase chain reaction amplification (recommendation level A) and serology (level B). Neuroimaging, preferably by MRI, is essential (level B). Lumbar puncture can follow neuroimaging when immediately available, but if this cannot be performed immediately, LP should be delayed only under unusual circumstances. Brain biopsy should be reserved only for unusual and diagnostically difficult cases. Patients must be hospitalized with easy access to intensive care units. Specific, evidence-based, antiviral therapy, acyclovir, is available for herpes encephalitis (level A) and may also be effective for varicella-zoster virus encephalitis. Ganciclovir and foscarnet can be given to treat cytomegalovirus encephalitis, and pleconaril for enterovirus encephalitis (IV class evidence). Corticosteroids as an adjunct treatment for acute viral encephalitis are not generally considered to be effective, and their use is controversial, but this important issue is currently being evaluated in a large clinical trial. Surgical decompression is indicated for impending uncal herniation or increased intracranial pressure refractory to medical management.

Current concepts of neuropathological diagnostics in practice: neurodegenerative diseases.

Definitive diagnosis of neurodegenerative diseases (NDDs) relies on the neuropathological evaluation. NDDs are defined as disorders with progressive loss of neurons showing distinct anatomical distribution, and accordingly different clinical phenotypes. Recent research has identified a spectrum of immunohistochemically detectable proteins deposited in the central nervous system which serve as a basis for protein-based disease classification. Accordingly, diagnostic criteria and disease staging have been updated. Furthermore, it has become evident that there is considerable overlap between deposited proteins and pathologies. This review summarizes recent achievements in neuropathological diagnosis and classification of NDDs and recommends approaches to be used during the diagnostic procedure in practice, thus to serve as guideline for a common level of diagnostic quality.

Ultrastructural study of florid plaques in variant Creutzfeldt-Jakob disease: a comparison with amyloid plaques in kuru, sporadic Creutzfeldt-Jakob disease and Gerstmann-Sträussler-Scheinker disease.

BACKGROUND: Although the histological features of the amyloid plaques in variant Creutzfeldt-Jakob disease (vCJD) are distinct from those in other forms of prion disease [kuru, sporadic Creutzfeldt-Jakob disease (sCJD) and Gerstmann-Sträussler-Scheinker disease (GSS)], their ultrastructural features have only been described in a single case report. AIMS: To study vCJD plaques systematically and compare them with plaques in kuru, sCJD, GSS and Alzheimer disease (AD). METHODS: Amyloid plaques were studied by transmission electron microscopy and image analysis in five cases of vCJD, three cases of GSS, two cases of sCJD, one case of kuru and five cases of AD. Immunohistochemistry was performed on paraffin sections from one case of vCJD, two cases of GSS, one case of kuru and two cases of sCJD. RESULTS: The florid plaques in vCJD were either compact or more diffuse; in both forms, the radiating fibrils were organized into thick 'tongues', in contrast to kuru plaques. Dystrophic neurites (DNs) containing lysosomal electron-dense bodies or vesicles surrounded florid plaques. Microglial cells were found within florid plaques; occasional amyloid fibrils were identified in membrane-bound pockets of microglial cells. In vCJD, there was significant tau immunoreactivity in DNs around florid plaques while, in sCJD, GSS and kuru, minimal tau immunoreactivity was observed around plaques. CONCLUSIONS: The ultrastructure of the florid plaques and DNs in vCJD is more reminiscent of neuritic plaques in AD than kuru or multicentric plaques. These findings may reflect differences both in the strains of the transmissible agents responsible for these disorders and in host factors.

Danon disease: case report and detection of new mutation.

Danon disease is an X-linked disorder resulting from mutations in the lysosome-associated membrane protein-2 (LAMP2) gene. We report a male patient with skeletal myopathy, mental retardation, and massive hypertrophic obstructive cardiomyopathy necessitating heart transplantation. Immunohistochemistry of skeletal muscle and leukocytes, western blot analysis of leukocytes and cardiac muscle, flow cytometry, and DNA sequencing were performed. Muscle biopsy revealed autophagic vacuolar myopathy and lack of immunohistochemically detectable LAMP-2. Diagnosis of Danon disease was confirmed by western blot analysis of myocardial tissue and peripheral blood sample of the patient showing deficiency of LAMP-2 in myocardium and leukocytes. Moreover, absence of LAMP-2 in lymphocytes, monocytes and granulocytes was shown by flow cytometric analysis. Genetic analysis of the LAMP2 gene revealed a novel 1-bp deletion at position 179 (c.179delC) at the 3' end of exon 2, resulting in a frameshift with a premature stop codon.

The role of parvalbumin and calbindin D28k in experimental scrapie.

AIMS: Prion diseases are generally characterized by pronounced neuronal loss. In particular, a subpopulation of inhibitory neurones, characterized by the expression of the calcium-binding protein parvalbumin (PV), is selectively destroyed early in the course of human and experimental prion diseases. By contrast, nerve cells expressing calbindin D28 k (CB), another calcium-binding protein, as well as PV/CB coexpressing Purkinje cells, are well preserved. METHODS: To evaluate, if PV and CB may directly contribute to neuronal vulnerability or resistance against nerve cell death, respectively, we inoculated PV- and CB-deficient mice, and corresponding controls, with 139A scrapie and compared them with regard to incubation times and histological lesion profiles. RESULTS: While survival times were slightly but significantly diminished in CB-/-, but not PV-/- mice, scrapie lesion profiles did not differ between knockout mice and controls. There was a highly significant and selective loss of isolectin B(4)-decorated perineuronal nets (which specifically demarcate the extracellular matrix surrounding the 'PV-expressing' subpopulation of cortical interneurones) in scrapie inoculated PV+/+, as well as PV-/- mice. Purkinje cell numbers were not different in CB+/+ and CB-/- mice. CONCLUSIONS: Our results suggest that PV expression is a surrogate marker for neurones highly vulnerable in prion diseases, but that the death of these neurones is unrelated to PV expression and thus based on a still unknown pathomechanism. Further studies including the inoculation of mice ectopically (over)expressing CB are necessary to determine whether the shortened survival of CB-/- mice is indeed due to a neuroprotective effect of this molecule.

Determinants of diagnostic investigation sensitivities across the clinical spectrum of sporadic Creutzfeldt-Jakob disease.

To validate the provisional findings of a number of smaller studies and explore additional determinants of characteristic diagnostic investigation results across the entire clinical spectrum of sporadic Creutzfeldt-Jakob disease (CJD), an international collaborative study was undertaken comprising 2451 pathologically confirmed (definite) patients. We assessed the influence of age at disease onset, illness duration, prion protein gene (PRNP) codon 129 polymorphism (either methionine or valine) and molecular sub-type on the diagnostic sensitivity of EEG, cerebral MRI and the CSF 14-3-3 immunoassay. For EEG and CSF 14-3-3 protein detection, we also assessed the influence of the time point in a patient's illness at which the investigation was performed on the likelihood of a typical or positive result. Analysis included a large subset of patients (n = 743) in whom molecular sub-typing had been performed using a combination of the PRNP codon 129 polymorphism and the form of protease resistant prion protein [type 1 or 2 according to Parchi et al. (Parchi P, Giese A, Capellari S, Brown P, Schulz-Schaeffer W, Windl O, Zerr I, Budka H, Kopp N, Piccardo P, Poser S, Rojiani A, Streichemberger N, Julien J, Vital C, Ghetti B, Gambetti P, Kretzschmar H. Classification of sporadic Creutzfeldt-Jakob disease based on molecular and phenotypic analysis of 300 subjects. Ann Neurol 1999; 46: 224-233.)] present in the brain. Findings for the whole group paralleled the subset with molecular sub-typing data available, showing that age at disease onset and disease duration were independent determinants of typical changes on EEG, while illness duration significantly influenced positive CSF 14-3-3 protein detection; changes on brain MRI were not influenced by either of these clinical parameters, but overall, imaging data were less complete and consequently conclusions are more tentative. In addition to age at disease onset and illness duration, molecular sub-type was re-affirmed as an important independent determinant of investigation results. In multivariate analyses that included molecular sub-type, time point of the investigation during a patient's illness was found not to influence the occurrence of a typical or positive EEG or CSF 14-3-3 protein result. A typical EEG was most often seen in MM1 patients and was significantly less likely in the MV1, MV2 and VV2 sub-types, whereas VV2 patients had an increased likelihood of a typical brain MRI. Overall, the CSF 14-3-3 immunoassay was the most frequently positive investigation (88.1%) but performed significantly less well in the very uncommon MV2 and MM2 sub-types. Our findings confirm a number of determinants of principal investigation results in sporadic CJD and underscore the importance of recognizing these pre-test limitations before accepting the diagnosis excluded or confirmed. Combinations of investigations offer the best chance of detection, especially for the less common molecular sub-types such as MV2 and MM2.

Histopathological prognostic factors in medulloblastoma: high expression of survivin is related to unfavourable outcome.

Standard postoperative treatment of medulloblastoma consists of craniospinal irradiation and chemotherapy. Currently, only clinical factors are used for therapy stratification. To optimise treatment and patient outcome, biological prognostic markers are needed. In the present study we tested the prognostic influence of four histopathological parameters considered in recent publications as prognostic factors in medulloblastoma. We analysed a series of 82 Austrian medulloblastoma patients who were treated according to the consecutive HIT protocols for medulloblastoma conducted by the German Society of Paediatric Haematology and Oncology. Histological subtype and immunohistochemical expression of erbB-2, TRKC, and survivin were determined on paraffin embedded tumour tissue and correlated with patient outcome. Statistical analysis showed a significant correlation of high expression levels of survivin with decreased survival. None of the other investigated histopathological factors correlated significantly with patient outcome. Our data indicate that high survivin expression is related to unfavourable clinical outcome in medulloblastoma patients.

DEC1 expression in 1p-aberrant oligodendroglial neoplasms.

BACKGROUND: Expression of hypoxia-related tissue factors in 1p-aberrant oligodendroglial neoplasms diminishes patient outcome. Differentiated embryo-chondrocyte expressed gene 1 (DEC1) has been described as novel hypoxia-related tissue factor. In our study, we assessed the expression of DEC1 in 1p aberrant oligodendroglial neoplasms and its association with necrosis and expression of hypoxia-inducible factor 1alpha (HIF-1alpha), carbonic anhydrase-9 (CA9), and vascular endothelial growth factor-mRNA (VEGF). MATERIALS AND METHODS: 44 primary and 16 recurrent oligodendroglial neoplasms with 1p-aberrations were investigated immunohistochemically for the expression of DEC1, HIF-1alpha, and CA9. Expression of VEGF was investigated using in situ hybridization. DEC1 expression was correlated with necrosis and with expression of HIF-1alpha, CA9, and VEGF. RESULTS: DEC1 was expressed in tumor cell nuclei, and occasionally in nuclei of endothelial cells, and glial and neuronal cells of surrounding brain tissue. High expression (>10% of tumor cells immunolabeled) of DEC1 was found in 56 cases, low expression (<10% of tumor cells immunolabeled) was found in 3 cases. In 1 case no expression of DEC1 was evident. DEC1 expression showed no topographical association with necrosis or expression of HIF-1alpha, CA9, or VEGF. CONCLUSION: DEC1 expression is found in the majority of 1p-aberrant oligodendroglial neoplasms and does not correlate with necrosis or expression of HIF-1alpha, CA9, VEGF. Thus, immunohistochemical analysis of DEC1 expression is in our hands not suitable for detection of tissue hypoxia in this type of primary brain tumor.

Predictors of survival in sporadic Creutzfeldt-Jakob disease and other human transmissible spongiform encephalopathies.

A collaborative study of human transmissible spongiform encephalopathies has been carried out from 1993 to 2000 and includes data from 10 national registries, the majority in Western Europe. In this study, we present analyses of predictors of survival in sporadic (n = 2304), iatrogenic (n = 106) and variant Creutzfeldt-Jakob disease (n = 86) and in cases associated with mutations of the prion protein gene (n = 278), including Gerstmann-Sträussler-Scheinker syndrome (n = 24) and fatal familial insomnia (n = 41). Overall survival for each disease type was assessed by the Kaplan-Meier method and the multivariate analyses by the Cox proportional hazards model. In sporadic disease, longer survival was correlated with younger age at onset of illness, female gender, codon 129 heterozygosity, presence of CSF 14-3-3 protein and type 2a prion protein type. The ability to predict survival based on patient covariates is important for diagnosis and counselling, and the characterization of the survival distributions, in the absence of therapy, will be an important starting point for the assessment of potential therapeutic agents in the future.

Herpes simplex virus (HSV) DNA in microglial nodular brainstem encephalitis.

Thirty-four brains with microglial nodular brain stem encephalitis were retrospectively investigated for herpes simplex virus (HSV) and cytomegalovirus (CMV) by in situ hybridization (ISH) with biotinylated cDNA probes, and by immunocytochemistry with polyclonal and monoclonal antibodies on formalin fixed paraffin embedded serial tissue sections. In 16 cases (47%), HSV DNA was found by ISH in the nuclei of neurons in microglial nodules or in the adjacent parenchyma of the brainstem, and more rarely at various cerebellar and telencephalic sites. None of the 34 cases was labeled for CMV DNA and none revealed HSV or CMV antigens. Ten control brains without microglial nodules were not labeled. This study suggests an HSV etiology for many cases with microglial nodular brainstem encephalitis.

Distribution of parvalbumin-immunoreactive neurons in brain correlates with hippocampal and temporal cortical pathology in Creutzfeldt-Jakob disease.

There is a distinctive pattern of hippocampal involvement in Creutzfeldt-Jakob disease (CJD) and evidence for selective vulnerability of GABAergic neurons in experimental and human prion disease. We studied hippocampus and temporal cortex from human CJD and control autopsy brains and surgical cryptogenic temporal lobe epilepsy specimens for distribution and density of parvalbumin (PV) and calbindin-D28K (Cal) -positive neurons that are subpopulations of GABAergic neurons. Pathology was evaluated semiquantitatively in 8 regions in 23 CJD brains for severity of spongiform change, astrogliosis and pathological prion protein deposition. In CJD, pathology was severe in pre-parasubiculum and temporal cortex, and little or absent in CA1-4; PV+ neurons were severely reduced or absent in all cases, whereas Cal+ neurons were largely preserved. In controls, the density of PV+ neurons was highest in pre-parasubiculum and temporal cortex, and lowest in CA1-4. In cTLE, loss of PV+ neurons was seen only in CA1-4. The diffuse and severe loss of PV+ neurons in CJD, and the topographical correlation of tissue lesioning in CJD with density of PV+ neurons in controls suggest selective vulnerability and early loss of this subset of inhibitory neurons in CJD. This might relate to characteristic CJD symptoms such as myoclonus and the distinctive EEG pattern.

Fibroblasts can express glial fibrillary acidic protein (GFAP) in vivo.

Neuropathologists use anti-glial fibrillary acidic protein (GFAP) antibodies as specific markers for glial cells, and neurobiologists use GFAP for targeting transgenes to glial cells. Since GFAP has also been detected in non-glial cells, we systematically analyzed GFAP expression in human and murine non-CNS tissues using a panel of anti-GFAP antibodies. In human tissues we confirm previously observed GFAP expression in Schwann cells, myoepithelial cells, and chondrocytes, and show for the first time GFAP expression in fibroblasts of epiglottic and auricular perichondrium, ligamentum flavum, and cardiac valves. In mice we show GFAP expression in Schwann cells, bone marrow stromal cells, chondrocytes, and in fibroblasts of dura mater, skull and spinal perichondrium, and periosteum, connective stroma of oral cavity, dental pulp, and cardiac valves. Anti-GFAP immunoblotting of human non-CNS tissues reveals protein bands with a molecular mass ranging between approximately 35 and approximately 42 kDa. In GFAP-v-src transgenic mice, whose oncogenic v-src transgene transforms GFAP expressing cells, non-CNS tumors originate from fibroblasts. We conclude that human and murine fibroblasts can express GFAP in vivo. The somatic distribution of GFAP expressing fibroblasts indicates origin from the neural crest. Development of non-CNS tumors from fibroblasts in GFAP-v-src mice functionally confirms GFAP expression in these cells.

An antigenic profile of Lewy bodies: immunocytochemical indication for protein phosphorylation and ubiquitination.

An antigenic profile of subcortical and cortical Lewy bodies was determined in the presence or absence of neurofibrillary tangles in the same brain using antisera and monoclonal antibodies to various cytoskeletal elements as well as to determinants not present in the normal cytoskeleton. The cores of many Lewy bodies were strongly reactive with a monoclonal antibody to paired helical filaments which has been shown to recognize ubiquitin. This antibody also stained Marinesco bodies in the same tissue sections. Two monoclonal antibodies to phosphorylated epitopes of neurofilament proteins (SM I 31, SM I 34) stained the peripheries of about 40% of all discernable Lewy bodies on untreated paraffin sections. Reactivity with a monoclonal antibody to neurofilaments (SM I 33) appeared only after pretreatment of the sections with phosphatase. Lewy bodies did not bind antibodies to tau protein. Our results show that, as previously shown for neurofibrillary tangles, Lewy bodies also contain ubiquitin. The uncovering of neurofilament epitopes by treatment with phosphatase indicates that abnormal phosphorylation of cytoskeletal elements may play a role in the pathogenesis of the Lewy body.

Neuropathology of human immunodeficiency virus infection.

Neuropathology has defined novel HIV-specific diseases at tissue level: HIV encephalitis and HIV leukoencephalopathy. Both occur usually in the later stages of the AIDS infection and consistently demonstrate large amounts of HIV products. In contrast to this HIV-specific neuropathology, HIV-associated neuropathology features unspecific syndromes with disputed relation to HIV infection: myelin pallor, vacuolar myelopathy, vacuolar leukoencephalopathy, lymphocytic meningitis, and diffuse poliodystrophy. All types of neuropathology may contribute to clinical manifestation according to severity, extent, and distribution of lesions, but clinico-pathologic correlation may be poor in the individual case. Neuropathologic and other data suggest two major pathogenetic pathways of HIV-associated CNS damage: First, systemic and local increase of the virus load leads to HIV encephalitis or HIV leukoencephalopathy; this is corroborated by prominent HIV production within such lesions. Second, neuronotoxicity by HIV proteins or factors secreted from infected cells is supported by histological changes of diffuse poliodystrophy and by morphometric loss of frontocortical neurons.

Fatal familial insomnia around the world. Introduction.

Despite decades of research, much intensified in recent years, transmissible spongiform encephalopathies (TSEs) or prion diseases have remained enigmatic in many aspects. Among these, the intricate connection between infectivity and genetics, genotype-phenotype correlation, and pathogenesis of brain damage are major problems in need of clarification. Fatal familial insomnia (FFI) appears as an ideal model situation for answering some of these problems: it has been understood to have a distinctive clinicopathological phenotype based on a specific genotype as well as transmissibility. However, as always with good science, new data prompts more questions than it is able to answer. The following survey of FFI cases in Europe and around the world is no exception from this rule.

Severe, early and selective loss of a subpopulation of GABAergic inhibitory neurons in experimental transmissible spongiform encephalopathies.

Little is known about the pathogenetic basis of characteristic symptoms in transmissible spongiform encephalopathies (TSEs) such as myoclonus and characteristic EEG hyperactivity. We investigated the GABAergic system and its subpopulations in mice inoculated with experimental scrapie (ME7, RML, 22A strains) and Creutzfeldt-Jakob disease (CJD; Fujisaki strain), to study damage to inhibitory neurons. Since recent studies have shown electrophysiological changes in prion protein (PrP) knockout mice, we also studied mice lacking or overexpressing the PrP gene. Antibodies against glutamic acid decarboxylase (GAD), parvalbumin (PV), calbindin (CB), and calretinin (CR) were used to stain GABAergic neurons, and isolectin-B4 to stain perineuronal nets around PV+ neurons. In scrapie infected mice, cortical PV+ neurons were severely reduced while CB+ and CR+ neurons were well preserved. In CJD inoculated mice, loss of PV+ neurons was severe and occurred very early after inoculation. PrP-/- and tg20 mice showed normal appearance of PV, CB, CR, GAD+ neurons and their neuropil, and of isolectin-B4+ perineuronal nets. The early, severe and selective loss of cortical PV+ neurons in experimental scrapie and CJD suggest selective loss of PV+ GABAergic neurons as important event during disease development, possibly as one basis of excitatory symptoms in TSEs.