[Consensus statement "Dementia 2010" of the Austrian Alzheimer Society]

The Austrian Alzheimer Society developed evidence-based guidelines based on a systematic literature search and criteria-guided assessment with subsequent transparent determination of grades of clinical recommendation. The authors evaluated currently available therapeutic approaches for the most common forms of dementia and focused on diagnosis and pharmacological intervention, taking into consideration the situation in Austria. The purpose of these guidelines is the rational and cost-effective use of diagnostic and therapeutic measures in dementing illnesses. Users are physicians and all other providers of care for patients with dementia in Austria.

Senile dementia with tangles (tangle predominant form of senile dementia)

Senile dementia with tangles is a sporadic subset of very late onset dementia with preponderance in females over age 80 years. Neuropathology shows diffuse cerebral atrophy with neurofibrillary tangles, often ghost tangles, and neuropil threads almost limited to limbic areas (transentorhinal, entorhinal area, hippocampuS--not exclusively sector CA 1--and amygdala) with only rare and mild involvement of the neocortex, basal ganglia and brainstem (except nucleus basalis and locus ceruleus), absence of neuritic plaques and absence or scarcety of amyloid deposits. This pattern of fibrillary pathology corresponds to Braak stages III and IV or the "limbic" type of Alzheimer disease that is considered the main form in the oldest-old but escapes the current criteria for the morphologic diagnosis of Alzheimer disease. It is distinct from other tau- or tangle-pathology related conditions, e.g. progressive supranuclear palsy, autosomal dominant dementia with tangles, and diffuse tangles with calcification. Very low prevalence of ApoE e4 allele (0.03-0.11%) and higher frequency of ApoE e3 and/or e2 suggest a lack of promoting effect of e4 and a possible protecting effect of e2/3 on amyloidogenesis. Senile dementia with tangles is suggested to be a variant of Alzheimer disease occurring in the oldest-old, but its nosological position within aging disorders of the brain is still controversy.

Immunoreactivities of amyloid beta peptide((1-42)) and total tau protein in lumbar cerebrospinal fluid of patients with normal pressure hydrocephalus

Immunoreactivities of amyloid beta peptide((1-42)) (Abeta42-IR) and total tau protein (TTIR) were measured in lumbar cerebrospinal fluid of 48 patients (12 patients in each group) with normal pressure hydrocephalus (NPH), vascular dementia (VD), Alzheimer's disease (AD), Parkinson's disease without dementia (PD) and 24 controls (CON) using sensitive and specific enzyme immunoassays. TTIR in NPH was not significantly changed compared with VD, PD and CON, while NPH-Abeta42-IR was significantly decreased compared with PD and CON. In AD, significant increases of TTIR and significant decreases of Abeta42-IR were found. Using a TTIR by Abeta42 plot, all NPH, PD, and CON samples were within the non-AD plot region. 92% of AD and VD samples were within the AD and non-AD area, respectively. We conclude that combined measurement of Abeta42-IR and TTIR contributes to the differential diagnosis of NPH vs. AD and of AD vs. VD, respectively.

Concurrence of sarcoidosis and aortitis: case report and review of the literature

Takayasu arteritis (TA) is a rare manifestation of systemic large vessel vasculitis which affects predominantly the aorta and its main branches, but often remains unrecognised owing to delayed diagnosis and non-characteristic clinical features. Sarcoidosis, too, is a systemic inflammatory disease which can affect virtually any organ system. Reports about the coincidence of both diseases have appeared. The case presented here is characterised by a significant time lag between detection of TA and appearance of clinical signs of sarcoidosis. The woman, now 39 years old, had erythema nodosum, circumscript alopecia, and recurrent uveitis, which dated back to 1980 and was attributed to sarcoidosis. At least 12 years later aortic valve insufficiency with progressive cardiac failure developed. Histology performed at the time of aortic valve prosthesis in 1997 disclosed a diagnosis of TA, which was confined to the aortic root. Incidentally, sarcoidosis was diagnosed in adjacent lymph nodes. A thorough check up failed to detect further manifestations of TA; thus, possibly, the patients had aortitis similar to, but not identical with, TA. Several related cases previously reported are discussed, suggesting that both diseases may be inherently related as they are characterised by certain non-specific, immunoinflammatory abnormalities. This case report suggests that the prevalence of TA, or related forms of arteritis, may be higher than expected and should be considered, especially in younger patients with non-characteristic cardiovascular symptoms and suspected systemic inflammatory disease. Moreover, the association with sarcoidosis in this and other previously described cases suggests that the two diseases may be related and that TA or TA-like vasculitis may even be a complication of sarcoidosis.

Giant visually-evoked potentials without myoclonus in the Heidenhain type of Creutzfeld-Jakob disease

In a 64-year old woman with progressive visual impairment for 4 weeks, probable Creutzfeld-Jakob disease without myoclonus was diagnosed after rapidly progressive mental deterioration had also developed, and CSF and EEG showed characteristic findings. Pattern-reversal and flash visually-evoked potentials, recorded 5, 6, 7 and 8 weeks after onset, showed a maximum P100 latency of 210 ms, 8 weeks after onset, and a maximum N75/P100 amplitude of 33.1 microV, 5 weeks after onset. While the P100 latency progressively increased, the N75/P100 amplitude continuously decreased after reaching its maximum. In the Heidenhain type of Creutzfeld-Jakob disease giant visually-evoked potentials may be recorded during the early stages of the disease, even in the absence of myoclonus. Visually-evoked potentials may prove useful in diagnosing Creutzfeld-Jakob disease with atypical initial presentation.

Apoptosis of T lymphocytes in acute disseminated encephalomyelitis

Apoptosis has been shown to be an efficient mechanism involved in clearance of T lymphocytes from the brains of animals with acute experimental autoimmune encephalomyelitis (EAE), an animal model for human multiple sclerosis. In this report we describe a case of acute disseminated encephalomyelitis following general measles infection. In this disease, which closely mimics the pathology of acute EAE we found a high percentage (30%) of apoptotic T cells. This indicates that in both rodent and human brain clearance of T cell-mediated inflammation follows similar mechanisms.

Improved discrimination of AD patients using beta-amyloid(1-42) and tau levels in CSF

OBJECTIVE

To evaluate CSF levels of beta-amyloid(1-42) (Abeta42) alone and in combination with CSF tau for distinguishing AD from other conditions.

METHODS

At 10 centers in Europe and the United States, 150 CSF samples from AD patients were analyzed and compared with 100 CSF samples from healthy volunteers or patients with disorders not associated with pathologic conditions of the brain (CON), 84 patients with other neurologic disorders (ND), and 79 patients with non-Alzheimer types of dementia (NAD). Sandwich ELISA techniques were used on site for measuring Abeta42 and tau.

RESULTS

Median levels of Abeta42 in CSF were significantly lower in AD (487 pg/mL) than in CON (849 pg/mL; p = 0.001), ND (643 pg/mL; p = 0.001), and NAD (603 pg/mL; p = 0.001). Discrimination of AD from CON and ND was significantly improved by the combined assessment of Abeta42 and tau. At 85% sensitivity, specificity of the combined test was 86% (95% CI: 81% to 91%) compared with 55% (95% CI: 47% to 62%) for Abeta42 alone and 65% (95% CI: 58% to 72%) for tau. The combined test at 85% sensitivity was 58% (95% CI: 47% to 69%) specific for NAD. The APOE e4 gene load was negatively correlated with Abeta42 levels not only in AD but also in NAD.

CONCLUSIONS

The combined measure of CSF Abeta42 and tau meets the requirements for clinical use in discriminating AD from normal aging and specific neurologic disorders.

[Frontal lobe dementia. Clinical-pathologic case reports]

Frontal lobe dementia (FLD) is characterised clinically by personality changes and a progressive speech disorder finally leading to mutism. In the course of the disease also other neurological syndromes may occur such as parkinsonism, a partial Klüver-Bucy-syndrome or a degeneration of motoneurons (FLD + MND). The latter leads to death within about three years. The clinical diagnosis of FLD is supported by functional (SPECT) and morphological (CT, MRI) investigations. From 1988 to 1997, 9 cases of FLD (6 female, 3 male) were clinically diagnosed at our department of Gerontology, LNK Linz. In two of these cases the clinical diagnosis was confirmed histopathologically. Characteristically, all except one patients showed a presenile beginning of the disease. The clinical course was slowly progressive with a mean duration of about 10 years. Special attention was given to additional signs and symptoms of motor neuron disease, parkinsonism and hyperorality. Six patients suffered from FLD + MND; parkinsonism (rigid-akinetic type) and a partial Klüver-Bucy-syndrome were diagnosed in 5 cases each. In histopathological investigations the incidence of FLD seems to increase. This type of dementia should be considered as an important diagnosis differential of presenile dementia-syndromes.

Neuropathology of Alzheimer's disease: a critical update

The unequivocal diagnosis of Alzheimer's disease (AD) rests on histopathological evidence at brain autopsy or biopsy. The morphology of AD includes cerebral atrophy, deposition of beta A4 amyloid (A beta) (senile plaques and amyloid angiopathy), neuritic changes (neuritic plaques, neurofibrillary tangles (NFT) and neuropil threads) with formation of paired helical filaments (PHF) containing polymerized hyperphosphorylated tau protein triplet, causing disruption of the neuronal cytoskeleton with loss of synapses and neurons, with altered cortico-cortical connectivity, leading to disconnection of the cerebral cortex. Defining criteria for the morphologic diagnosis of AD is difficult due to the phenotypic heterogeneity of the disease, the absence of specific markers, and overlap of AD morphology with that observed in non-demented elderly individuals. This gray zone between normal to pathologic aging and full-fledged AD represents an important diagnostic problem and should be overcome by better standardized criteria that will allow to minimize interrater and interlaboratory variability in the diagnosis of AD. Current criteria for the morphologic diagnosis of AD are based on (semi)quantitative assessment of diffuse and neuritic plaques (NIA), exclusively neuritic plaques (CERAD), plaques and NFT in neocortex and hippocampus (Tierney et al., 1988), and staging of hierarchic spreading of neuritic AD changes (Braak and Braak, 1991); all of them have weaknesses and need to be revalidated. Multivariant analysis of an autopsy series of elderly subjects revealed significant correlations between psychostatus and both the CERAD criteria and Braak staging. Recent recommendations of the NIA-Reagan Institute for the morphologic diagnosis of AD are presented. Although the role of plaques and NFT in the pathogenesis of AD remains undetermined, clinicopathological correlative studies have shown that both lesions, if present in sufficient numbers, particularly in the neocortex, are considered the best morphological signposts for AD. Recent studies on neuron death in AD that, at least in part, appears different from classical apoptosis and may precede the symptomatic stage of AD, have shown varying results indicating only indirect relationship between DNA fragmentation and both A beta deposition and NFTs. Both these AD-typical markers appear to increase the risk of cells to degenerate, but are not the sole responsibles of the degenerative process in AD, the basic mechanisms of which remain to be elucidated.

Biological markers for the diagnosis of Alzheimer's disease

A diagnostic test for Alzheimer's disease (AD) based on biochemical markers in the cerebrospinal fluid can help improve diagnostic accuracy, which currently is approximately 90%, leaving every tenth AD patient undiagnosed or falsely diagnosed as having the disease. From all biochemical abnormalities described in AD patients, those related to the hallmark neuropathologic lesions, deposition of amyloid and formation of paired helical filaments mainly consisting of abnormally phosphorylated tau protein, are the most promising and the best documented, even though other markers bear some potential and remain to be further studied. Determining an increase of tau and a reduction of A beta 42 bears satisfactory, even though not absolute specificity for AD and represents a true aid for clinicians in diagnosing AD during the patients lifetime. It remains open if these markers will be helpful for the most challenging goal, diagnosing AD in the preclinical phase, when, according to morphological data, high amounts of these pathological proteins are already deposited in the brain tissue.

Alzheimer disease: DNA fragmentation indicates increased neuronal vulnerability, but not apoptosis

Although nerve cell loss is prominent in certain brain regions in Alzheimer disease (AD), it is currently unresolved how these cells die. Recent studies unanimously agree that there are more neurons displaying DNA fragmentation in AD compared with normal controls. However, controversy remains as to whether cell death is mediated by apoptosis or necrosis. We addressed this question by comparing AD lesions with those from cases with pontosubicular neuron necrosis (PSNN), a human pathological condition with unequivocal neuronal apoptosis, with regard to cell and nuclear morphology, immunohistochemistry, and in situ tailing. Immunohistochemistry was performed for an array of proteins with presumptive roles in the apoptotic process or the protection thereof, i.e. a recently described apoptosis-specific protein (ASP), the transcription factor c-Jun, Bcl-2, and various stress proteins: alpha B-Crystallin, heat shock protein (HSP) 27, HSP 65, HSP 70, HSP 90, and ubiquitin. Apoptotic neurons in PSNN displayed chromatin condensation, nuclear fragmentation, and cytoplasmic condensation. They were labeled with the in situ tailing technique and stained for the ASP. Despite the large numbers of cells with DNA fragmentation identified in the hippocampus of AD brains, only exceptional cells displayed the morphological characteristics of apoptosis or labeled for the ASP. We suggest that the increased rate of neuronal DNA fragmentation in AD patients indicates a higher susceptibility of the cells to metabolic disturbances compared with normal controls. The large number of cells with DNA fragmentation most likely reflects metabolic disturbances in the premortem period, and cell destruction is mediated through necrosis rather than apoptosis.

Neuropathologic diagnosis of Alzheimer disease: consensus between practicing neuropathologists?

In an attempt to gather information on procedures, criteria, and possible difficulties, we have sent a detailed questionnaire on the postmortem diagnosis of Alzheimer disease (AD) to 169 neuropathologists in the German-speaking countries--Germany, Austria, and Switzerland. Of a total of 104 responses, 65 completed questionnaires were evaluated statistically. Fifty-nine percent of all respondents consider the neuropathologic diagnosis of AD a problem. Although 38% consider themselves able to establish the diagnosis without knowledge of clinical data, 29% do not believe this is possible. Thirty-eight percent opine that the presence of neurofibrillary tangles is not a prerequisite for a positive diagnosis, and 3% believe that examination of the hippocampal formation is unnecessary. For 6% of the respondents, neither a silver stain a silver stain nor thioflavin S is necessary. Ninety-seven percent believe that the availability of explicit diagnostic criteria would be helpful; by contrast, only 43% have exact knowledge of the National Institute of Aging criteria, and only 29% have exact knowledge of the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) criteria. Only every fourth neuropathologist uses these criteria regularly, and the validity of current diagnostic criteria is challenged by a considerable number of respondents. Many pathologists consider the quantification of plaques and tangles problematic, are confused by a lacking correlation of the pathology with the clinical picture, and believe that the gray zone between normal aging and full-fledged AD represents a major diagnostic problem. Our survey shows that there currently is no consensus on diagnostic procedures and criteria used in practice. This stresses the need for precise diagnostic guidelines and continuing information of actively practicing neuropathologists to achieve higher interlaboratory reliability of the diagnosis of AD.

Low prevalence of apolipoprotein E epsilon 4 allele in the neurofibrillary tangle predominant form of senile dementia

Apolipoprotein E (apoE) genotypes were analyzed in a subset of demented very old patients who share a uniform neuropathological picture consisting of various numbers of neurofibrillary tangles (NFT) in allocortical areas of the inferomedial temporal lobe without significant numbers of either diffuse amyloid or neuritic plaques. Among 18 patients with this condition referred to as NFT-predominant senile dementia (average age at death 87 +/- 4.7 years), we found allele frequencies of 0.11 epsilon 2, 0.86 epsilon 3 and 0.03 epsilon 4, which are significantly different from allele frequencies reported in Alzheimer's disease (0.04 epsilon 2, 0.59 epsilon 3 and 0.38 epsilon 4). The low prevalence of the apoE epsilon 4 allele in this subset of patients is striking and suggests that NFT-predominant senile dementia is a dementing neurodegenerative disease in which the deposition of A beta-amyloid did not occur, possibly due to protective effects of epsilon 2 and/or epsilon 3 alleles or lack of a promoting effect of apoE epsilon 4 on amyloidogenesis. We propose that NFT-predominant dementia is a variant of Alzheimer's disease occurring in the very old.

Proposals for re-evaluation of current autopsy criteria for the diagnosis of Alzheimer's disease

Defining criteria for the postmortem diagnosis of Alzheimer's disease (AD) has proven difficult due to the phenotypical heterogeneity of the disease, the absence of a specific disease marker and an overlap of AD neuropathology with that observed in a number of nondemented aged individuals. Even though the role of plaques and tangles in the pathogenesis of AD remains undetermined, a host of clinicopathological correlative studies have shown that both lesions, if present in sufficient numbers-particularly in the neocortex-are still to be considered the best morphological signposts for the disease. All currently used criteria for the neuropathologic diagnosis of AD have some weaknesses and need to be reestablished and revalidated. Multivariant analysis in a personal autopsy series of elderly subjects revealed significant correlations between psychostatus and both the CERAD criteria and Braak staging of neuritic Alzheimer-type lesions, and less concordance with the National Institutes of Aging and Tierney criteria. We propose a set of histopathologic diagnostic criteria for both definite and preclinical AD that rely on various constellations of both different types of plaques, except diffuse amyloid deposits, and neurofibrillary tangles, in allocortical and isocortical areas considering their topographic pattern. This set of criteria encompasses phenotypic variations of the pathology and takes into account the chronic, progressive course of AD. It allows the detection of preclinical disease in subjects in whom dementia is not reported and includes those cases in the morphological gray zone between "normal" aging and full-fledged AD that practicing neuropathologists consider the most problematic. The set of criteria includes guidelines concerning tissue sampling and processing, and standardized staining methods that should allow neurologists to minimize interrater and interlaboratory variability in the assessment of morphologic lesions and the diagnosis of AD.

Mechanisms of cell death in Alzheimer's disease

The etiology of Alzheimer's disease (AD) as well as its exact pathogenesis are unknown. Eventhough the deposition of beta A4 and the formation of neurofibrillary tangles represent impressive morphological hallmarks of the disease, several lines of evidence suggest that both lesions are not sufficient as causes of the neurodegenerative process. On the other hand, in vitro studies have shown that beta A4 is neurotoxic and is able to induce apoptotic cell death in neuronal cell cultures. Cells dying by apoptosis (programmed cell death) can be visualized in the tissue with a molecular biologic technique detecting fragmented nuclear DNA. Using this method, we have detected 50 x more neurons and 25 x more glial cells with nuclear DNA fragmentation in the brains of patients with AD than in non-demented controls. In contrast to previous studies, most of these cells did not reveal the characteristic morphological hallmarks of apoptosis. Most dying cells were not located within amyloid deposits and most dying cells did not bear a tangle. On the other hand, being in physical contact with an amyloid deposit increased the risk of a cell to dye by factor 5.7 and carrying a neurofibrillary tangle imposed a 3 times higher risk compared to unaffected nerve cells. Taken together, these data indicate that nerve cell death in AD occurs via a mechanism of programmed cell death different from classical apoptosis. Eventhough plaques and tangles increase the risk of cells to degenerate, both lesions are not the sole responsibles of the degenerative process, suggesting the existence of other factors that trigger the initiation of the cell death program in AD.

[Histopathologic studies in dementia--comparison with clinical findings]

This paper compares the clinical diagnosis of dementia with the result of the neuropathological brain examination in 23 patients. Aim of this investigation was a verification of the clinical diagnosis. The diagnosis was based on the clinical findings, the Mini Mental State Examination, DSM-III-R classification of dementia, the NINCDS-ADRDA-criteria, results of laboratory tests, EEG, CCT and sonography. A total of 70% of the clinical diagnosis corresponded to the neuropathological results. In 25% of these cases which clinically showed the characteristics of Alzheimer's disease histopathological findings delineated dementia of non-Alzheimer-type. These results underline the importance of additional histopathological investigations in the diagnosis of dementia.

The apolipoprotein E epsilon 4 allele in Parkinson's disease with Alzheimer lesions

The association between the apolipoprotein E (ApoE) epsilon 4 allele and Parkinson's disease (PD) with coexistent dementia has remained controversial. We determined ApoE allele frequencies in 35 subjects with neuropathologically confirmed Lewy body Parkinsonism with and without concomitant Alzheimer lesions, 27 patients with Alzheimer's disease (AD), and 54 controls without neurodegenerative disease. We hypothesized that if AD lesions in PD evolve by the same pathomechanism as in "pure AD," the ApoE epsilon 4 allele frequency in PD with AD lesions (PD+AD) and pure AD should be similar. The frequency of the ApoE epsilon 4 allele differed significantly between PD+AD (13.3%) and AD cases (35.2%), but not between PD+AD and PD without AD pathology (12.5%) or controls (11.1%). We conclude that the ApoE epsilon 4 allele does not function as a risk factor which influences the development of AD lesions in PD. Our data suggest that Parkinson's disease with Alzheimer lesions and Alzheimer's disease with coexistent Parkinsonian features represent two distinct entities at both the clinicopathological and molecular genetic levels.

On the relationship between measles virus and Alzheimer neurofibrillary tangles in subacute sclerosing panencephalitis

We have studied the relationship between measles virus and the accumulation of abnormally phosphorylated tau (PHF-tau) in nine cases of subacute sclerosing panencephalitis (SSPE). By assessing the presence of viral intranuclear inclusions and neurofibrillary tangles (NFT) in each case, we found no correlation between presence and amount of measles virus and the numbers of neurons containing PHF-tau. Immunohistochemical double labeling in a case with long duration of disease and severe histopathologic change revealed no strict colocalization of measles virus antigen and PHF-tau throughout different brain regions. In areas containing both antigens, most neurons carrying measles virus did not have a tangle and vice versa, eventhough some colocalization beyond that expected by chance was observed in specific cortical areas. These results indicate that, although secondary to viral infection, NFT formation in SSPE is not restricted to cells carrying viral antigen. Conversely, measles virus infected cells do not necessarily accumulate PHF-tau. This lack of colocalization at the cellular level, throughout different brain areas and among different cases suggests that the formation of NFT in SSPE is not directly induced by the infectious agent. The formation of NFT in this disease appears to be elicited through a specific type of tissue damage and, thus, to be an epiphenomenon. This pathogenetic detail may be of interest for our understanding of the role of neurofibrillary degeneration in the pathogenesis of other more frequent neurodegenerative diseases with cytoskeletal pathology.

Progressive supranuclear palsy: a clinicopathological study of 21 cases

The symptoms and signs used to diagnose progressive supranuclear palsy (PSP) should be easily identifiable by neuropathologists and neurologists as well as by movement disorder experts. The presence, at the time of death, of symptoms and signs that are used in published clinical criteria for the diagnosis of this disorder was searched for in 21 pathologically confirmed typical PSP cases. The following items, present in at least 80% of pathologically confirmed cases, can be considered as the most accurate clinical data for the diagnosis of PSP: non-familial parkinsonism, not improved by L-dopa therapy, with vertical voluntary gaze palsy; postural instability and falls; pseudobulbar palsy and dementia with frontal lobe-like syndrome; and a progressive course of less than 10 years. The definite diagnosis of PSP must be clinicopathological, and these minimal clinical data may be used for this purpose.

Neurofibrillary tangles in the brain of a 16 month old infant

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Correlations between mental state and quantitative neuropathology in the Vienna Longitudinal Study on Dementia

Quantitative clinicopathological correlation studies are one way to address the question of the relevance of morphological abnormalities in Alzheimer's dementia (AD). This paper summarizes results of the Vienna Longitudinal Study on Dementia obtained during the past few years and presents a critical discussion on the relevance of clinicopathological correlation studies for the pathogenesis of AD. Plotting of psychometric test scores against the numbers of plaques, tangles and neuropil threads in various cortical areas shows that significant correlations are due primarily to very high lesion counts in severely demented patients. These data indicate that neocortical neurofibrillary pathology can be considered an end-stage marker in the pathology of AD. On the other hand, the topographical staging of neuritic Alzheimer changes proposed by Braak and Braak (1991) appears to be a better reflection of the progression of the degenerative process than numerical lesion counts; there is a linear correlation between the Braak stages and Mini-Mental State scores in 122 aged individuals. Significant correlations are further obtained between the severity of dementia and the levels of a number of synaptic proteins including synaptophysin and the chromogranins. Taken together, our data suggest that none of the classical AD lesions, plaques and tangles, play a central role in the pathogenesis of dementia, a fact that is supported by a molecular biological study showing that there is no close relationship between these lesions and the neurons undergoing degeneration in AD. Whereas neuritic pathology is a useful histopathological marker for the diagnosis and staging of AD, the major correlate of cognitive deficits is the loss of corticocortical and subcorticocortical connections reflected by a depletion of synapses. This pathology may be induced by a mismetabolism of the beta-amyloid precursor proteins or their interaction with cytoskeletal proteins related to neuronal degeneration.

Validity and reliability of the preliminary NINDS neuropathologic criteria for progressive supranuclear palsy and related disorders

We investigated the validity and reliability of diagnoses made by eight neuropathologists who used the preliminary NINDS neuropathologic diagnostic criteria for progressive supranuclear palsy (PSP) and related disorders. The specific disorders were typical, atypical, and combined PSP, postencephalitic parkinsonism, corticobasal ganglionic degeneration, and Pick's disease. These disorders were chosen because of the difficulties in their neuropathologic differentiation. We assessed validity by measuring sensitivity and positive predictive value. Reliability was evaluated by measuring pairwise and group agreement. From a total of 62 histologic cases, each neuropathologist independently classified 16 to 19 cases for the pairwise analysis and 5 to 6 cases for the group analysis. The neuropathologists were unaware of the study design, unfamiliar with the assigned cases, and initially had no clinical information about the cases. Our results showed that with routine sampling and staining methods, neuropathologic examination alone was not fully adequate for differentiating the disorders. The main difficulties were discriminating the subtypes of PSP and separating postencephalitic parkinsonism from PSP. Corticobasal ganglionic degeneration and Pick's disease were less difficult to distinguish from PSP. The addition of minimal clinical information contributed to the accuracy of the diagnosis. On the basis of results obtained, we propose clinicopathologic diagnostic criteria to improve on the NINDS criteria.

Tau protein and apolipoprotein E in CSF diagnostics of Alzheimer's disease: impact on non Alzheimer's dementia?

Tau protein and apolipoprotein E are suggested to be biochemically related to neurofibrillary tangles and senile plaques in Alzheimer's disease (AD) brains. They can be detected as immunoreactive material (total tau immunoreactivity [TTIR] and apolipoprotein E-immunoreactivity [ApoEIR]) in the cerebrospinal fluid (CSF). TTIR and ApoE-IR have been measured in ex vivo lumbar and post mortem ventricular CSF in AD, other neurological diseases without cognitive impairment, elderly depressive patients, and young and elderly controls. In lumbar CSF, there was a highly significant increase of TTIR and a minor, insignificant decrease of ApoE-IR in CSF of AD patients. The latter result was also found in ventricular CSF, whereas TTIR showed no significant difference between groups in the rostral CSF compartment. As depressive periods in the elderly may mimick a dementing process, these findings contribute to the differential diagnosis of these disorders by showing a different neurobiochemical CSF profile. Work in progress will include a variety of non-Alzheimer's dementias and possibly will further increase the value of CSF investigation in neurodegenerative disorders.

[Necrotizing herpes simplex encephalitis as the cause of a progressive dementia syndrome]

HISTORY AND FINDINGS

A 65-year-old woman was twice hospitalized because of disorientation and insomnia with depression. In the course of antidepressive treatment the symptoms regressed each time so that the diagnosis was made of pseudo-dementia during depression. About a year after the first admission the symptoms recurred, despite continued antidepressive treatment. Clinical criteria now suggested Alzheimer-type dementia as the diagnosis.

COURSE AND TREATMENT

The symptoms of dementia increased markedly and generalized seizures requiring anticonvulsive drugs occurred after 4 months. Although IgG antibodies against Herpes simplex virus (HSV) were demonstrated in cerebrospinal fluid (CSF), no antiviral treatment was instituted because HSV encephalitis appeared unlikely at this stage. But the patient's mental and physical state further deteriorated in subsequent months. During an attack of pneumonia the patients became somnolent and went into status epilepticus. Repeat virological examination of CSF now revealed IgG and IgM antibodies against HSV, confirming encephalitis. Her condition markedly improved over 12 days on aciclovir, 750 mg 3 times daily intravenously. 6 weeks later the pneumonia recurred, as did the encephalitis, with apnoeic phases and massive left heart failure. The patient died a few days later. Immunohistochemical tests of brain tissue were positive for HSV type II.

CONCLUSIONS

This case report demonstrates that an investigation on dementia must include a complete liquor analysis. If HSV encephalitis is suspected, an antiviral therapy must be administered immediately. Even in adults who seem to have normal immunity HSV type II can cause HSV encephalitis.

Cell death in Alzheimer's disease evaluated by DNA fragmentation in situ

Loss of nerve cells is a hallmark of the pathology of Alzheimer's disease (AD), yet the patterns of cell death are unknown. By analyzing DNA fragmentation in situ we found evidence for cell death not only of nerve cells but also of oligodendrocytes and microglia in AD brains. In average, 30 times more brain cells showed DNA fragmentation in AD as compared to age-matched controls. Nuclear alterations suggestive of apoptosis were rare in degenerating cells. Even though the majority of degenerating cells were not located within amyloid deposits and did not contain neurofibrillary tangles, neurons situated within areas of amyloid deposits or affected by neurofibrillary degeneration revealed a higher risk of DNA fragmentation and death than cells not exposed to these AD changes.

Neurofibrillary tangle predominant form of senile dementia of Alzheimer type: a rare subtype in very old subjects

In a consecutive autopsy series of 580 demented elderly subjects, 256 with the clinical diagnosis of probable/possible Alzheimer's disease (AD), there were 10 cases aged between 80 and 99 years with moderate to severe dementia or confusional state in which neuropathological studies revealed abundant neurofibrillary tangles with predominant involvement of the allocortex (entorhinal region, subiculum, CA 1 sector of hippocampus, amygdala) but no or only very few senile plaques. Small numbers of diffuse deposits of beta A4 amyloid protein were present in the entorhinal cortex of 3 and in the isocortex of 5 brains, while neuritic plaques were totally absent. Only a few cases of this "senile dementia with tangles only" or, more correctly, "neurofibrillary predominant type of AD" corresponding to the limbic stage of neuritic AD pathology have been described in the literature. This rare subtype occurring in very old (over 80 years of age) subjects that does not fall within the currently used neuropathological criteria for diagnosis of AD warrants further clinico-pathological documentation.

Alzheimer paired helical filaments. Restoration of the biological activity by dephosphorylation

In a normal mature neuron, microtubule associated protein tau promotes the assembly of tubulin into microtubules and maintains the structure of microtubules. In Alzheimer disease brain, tau is abnormally hyperphosphorylated and is the major protein subunit of paired helical filaments (PHF). In the present study, the biological activity of tau in PHF and the effect of dephosphorylation on this activity were examined. PHF were isolated from Alzheimer disease brains and tau from the untreated or alkaline phosphatase-treated PHF was extracted by ultrasonication in microtubule assembly buffer. Tubulin was isolated by phosphocellulose chromatography of three cycled microtubules from bovine brain. PHF-tau did not promote assembly of bovine tubulin into microtubules whereas tau from the dephosphorylated PHF produced a robust microtubule assembly. These studies suggest (i) that in Alzheimer disease tau in PHF is functionally inactive because of abnormal phosphorylation and (ii) that the abnormally phosphorylated site(s) in PHF that inactivates PHF-tau is accessible to enzymatic dephosphorylation in vitro.

Neuropathological staging of Alzheimer lesions and intellectual status in Alzheimer's and Parkinson's disease patients

In both Alzheimer's disease (AD) and Parkinson's disease (PD), neurofibrillary tangles (NFT), in contrast to amyloid deposits, show a hierarchical spreading pattern from the allocortex to isocortical association areas with early involvement of the entorhinal region, a major relay station between hippocampus and isocortex. Based on the distribution pattern of NFT in human brain, a neuropathological staging of neuritic AD pathology has been proposed. Comparative studies of this neuropathological staging of neuritic AD changes with psychometrically assessed intellectual status (mini-mental state) in prospective cohorts of 29 aged individuals and 28 PD patients showed a linear correlation of morphological AD staging with the psychostatus in both disorders. The pattern of neuronal degeneration associated with neuritic AD pathology in both AD and PD may be an important basis of cognitive decline in both disorders.

Microglial reaction in Pick's disease

Number and morphology of microglial cells (MC) were compared in 6 cases each of Pick's disease (PD), Alzheimer's disease (AD) and controls using immunohistochemistry with the monoclonal antibody Ki-M1P. The severely involved neocortex of both PD and AD, and in particular the white matter subjacent to spongy PD lesions showed a marked increase of MC density, whereas non-affected PD areas and AD white matter showed no MC changes. The PD hippocampus, particularly the dentate gyrus, showed reduction of MC density and processes. We conclude that (1) MC reaction represents a major element of PD histopathology, and (2) density, morphology and distribution of MC are different in AD and PD.

Interrater reliability in the neuropathologic diagnosis of Alzheimer's disease

Three neuropathologists evaluated brain sections from 43 aged subjects for the presence of Alzheimer's disease. Moderate-to-substantial agreement was obtained. After discussion of disparate diagnoses, agreement was almost perfect for standardized and substantial for personal criteria. We conclude that reproducibility can be improved if diagnoses based on standardized criteria are discussed by at least two neuropathologists.

Synaptic pathology in Alzheimer's disease: immunological data for markers of synaptic and large dense-core vesicles

We have analysed several markers for small synaptic vesicles (synaptin-synaptophysin, p65 and SV2) and large dense-core vesicles (chromogranin A, secretogranin II/chromogranin C) in the brains of patients with Alzheimer's disease, and normal controls by immunoblotting and immunohistochemistry. In comparison to age-matched controls the levels of all three synaptic vesicle markers were decreased in temporal cortex of Alzheimer patients. On the other hand, the levels of chromogranin A were increased, and those of secretogranin II lowered. This resulted in a significant increase of the ratios of chromogranin A to synaptophysin, p65 or SV2 and of that for chromogranin A to secretogranin II. These increases were significantly correlated to clinical severity of dementia and extent of neuropathological changes. By immunohistochemistry a high percentage of senile plaques was found to contain chromogranin A-reactive dystrophic neurites, whereas synaptophysin reactivity within plaques was rare. These results indicate that the number of synaptic vesicles is lowered in Alzheimer's disease, and that one component of large dense-core vesicles, i.e. chromogranin A, is elevated. We, thus, suggest that in Alzheimer's brain distinct changes occur for both types of synaptic organelles.

Abnormal phosphorylation of tau precedes ubiquitination in neurofibrillary pathology of Alzheimer disease

On tissue sections of Alzheimer brain, 4 antibodies to tau immunolabel not only neurofibrillary tangles, neuritic plaques and neuropil threads but also the tangle-free cytoplasm of a subset of hippocampal and cortical neurons we believe to be at a stage of alteration preceding the formation of paired helical filaments (PHF). Pretreatment of tissue sections with alkaline phosphatase leads to an increase in staining intensity and in number of immunoreactive lesions with antibodies directed to an amino terminal and to a mid-region of the tau molecule. The diffuse neuronal staining could not be observed with any of 7 monoclonal antibodies recognizing ubiquitin. We conclude (1) that abnormal phosphorylation of tau occurs prior to its incorporation into PHF and leads to its accumulation in the nerve cell body and (2) that ubiquitin is seen associated only when a neurofibrillary tangle is already formed.

Cytoskeleton pathology in Alzheimer's disease and related disorders

The reported findings suggest that ubiquitination of pathological proteinaceous intracytoplasmic inclusions is not at all specific of AD. On the contrary it appears to be a general biochemical marker for disorders in the degradation of a variety of cytoskeletal and other cytoplasmic proteins. The pattern of affected cytoskeletal components is not specific of AD/SDAT tangles. Tau definitely is present also in PSP tangles and possibly in Pick bodies but not in Lewy bodies. Therefore it has to be considered that the intracytoplasmic accumulation of cytoskeletal protein/ubiquitin complexes in itself is a rather unspecific cellular reaction pattern, possibly a secondary reaction to cell injury of many types, especially, however, of neuronal aging. Nevertheless, the manifestation of NFT in an excessive quantity, intensity, and dynamics with severe concomitant lesions as in AD/SDAT undoubtedly is a true pathological and in this sense a disease-specific change.

Alzheimer neuropathology in non-Down's syndrome mentally retarded adults

We examined the brains of 385 mentally retarded adults aged 23-90 years without Down's syndrome (DS), metabolic disorder, or hydrocephalus to extend our knowledge about the occurrence of Alzheimer-type neuropathology in this population. Relevant measures of neuropathology also were related to selected information available from clinical records. The presence of one or more neurofibrillary tangles (NFT) and/or neuritic plaques (NP) was observed in 63.4% of all cases and varied with age. The prevalence of positive cases was higher when mental retardation was due to head trauma, congenital malformation, or familial factors and when a history of seizures was reported. Comprehensive morphometric analyses of neocortical, hippocampal and parahippocampal areas indicated that recommended age-specific quantitative criteria for the diagnosis of Alzheimer disease [Khachaturian ZS (1985) Arch Neurol 42:1097-1105] were met in 9.5% of cases less than 50 years of age, 54.2% between 50 and 65, 70% between 66 and 75, and 87% of the cases greater than 75 years of age. However, a limited immunohistochemical study revealed that in most cases the NP did not have a neuritic component containing paired helical filaments and in this respect most of the plaques observed in this population may differ from those most strongly associated with Alzheimer disease. In addition, substantial numbers of NFT were seen in frontal cortex, contrasting with results reported in the literature for nonretarded populations. The number of NP per mm2 consistently increased with age for all areas examined, while the relationship between NFT density and age varied across areas, and was clearly not monotonic.(ABSTRACT TRUNCATED AT 250 WORDS)

Cytoskeletal protein pathology and the formation of beta-amyloid fibers in Alzheimer's disease

Discovery of the abnormally phosphorylated tau in paired helical filaments, its accumulation preceding the formation of the tangles and the in vitro microtubule assembly defect suggest that an abnormality in the protein phosphorylation/dephosphorylation system is involved in the pathogenesis of Alzheimer cytoskeletal pathology. The levels of mRNA for the beta-amyloid precursor protein (beta APP) in the brain suggest that only a small deficiency in the processing of the precursor would be sufficient to account for the accumulation of beta-amyloid in Alzheimer brain. Identification of reticuloendothelial system cells responsible for the production/processing of beta-amyloid will help to elucidate the pathogenesis of the brain amyloidosis. The disproportionate accumulation of paired helical filaments and amyloid within the same affected brain and from disease to disease raises the possibility of different etiologies for each of these lesions coexisting in Alzheimer's disease.

Immunoreactivity of neuronal lipofuscin with monoclonal antibodies to the amyloid beta-protein

Monoclonal antibodies generated against a synthetic peptide corresponding to amino acids 1 to 24 of cerebrovascular amyloid beta-protein do not only stain amyloidotic blood vessels and the amyloid deposits of the (senile) neuritic plaques, but also the neuronal pigment lipofuscin. Staining of lipofuscin is observed in both cerebral and cerebellar cortices, subcortical nuclei as well as the brain stem, and is identical in Alzheimer and normal control brain. Western blots of a lipofuscin enriched fraction show an anti-beta-protein reactive polypeptide migrating at approximately 31 kDa position on SDS-polyacrylamide gel electrophoresis. These results suggest that this polypeptide is associated with lipofuscin and is most likely derived from the predicted amyloid precursor protein. This implicates that, unlike in Alzheimer's disease where this protein is also processed extraneuronally in a manner to release an amyloid fiber forming fragment, the end point of its processing in the nerve cell seems to accumulate on a lipopigment characteristic for normal aging.

Accumulation of abnormally phosphorylated tau precedes the formation of neurofibrillary tangles in Alzheimer's disease

The intraneuronal accumulation of paired helical filaments in the form of neurofibrillary tangles is one hallmark of the brain pathology in Alzheimer's disease. At certain predilection sites, a small number of similar lesions are also present in the brains of the majority of aged non-demented individuals. As suggested by several studies before, these abnormal cytoskeletal structures contain determinants of microtubule-associated protein tau and ubiquitin. The present study uses a morphological classification of neurofibrillary tangles into different stages of maturation, as suggested by Alzheimer in 1911, and shows by quantitative immunocytochemistry that early stages of neurofibrillary degeneration contain abnormally phosphorylated tau. Immunoreactivity for the altered tau is seen not only in tangles but also in the cytoplasm of some nerve cells lacking neurofibrillary tangles. Similar numbers of such immunoreactive neurons without tangles are present in age-matched non-demented individuals as in Alzheimer cases, but are absent in young controls. In contrast, incorporation of an epitope, recognized by a monoclonal antibody (3-39) raised to paired helical filaments, which is directed against a determinant residing in the 50-65 amino acid residue region of ubiquitin occurs late in the process of tangle maturation and is most pronounced in extracellular 'ghost tangles'. It is suggested that the accumulation of abnormally phosphorylated tau is one of the earliest cytoskeletal changes in the process of tangle formation. Exposure of certain ubiquitin epitopes in the pathological fibers may reflect an unsuccessful attempt of proteolytic degradation.