Rapidly progressive Alzheimer's disease: a multicenter update

The objective was to characterize a rapidly progressive subtype of Alzheimer's disease (rpAD). Multicenter (France, Germany, Japan, Spain) retrospective analyses of neuropathologically confirmed rpAD cases initially classified as prion disease due to their clinical phenotype were performed. Genetic properties, cerebrospinal fluid biomarkers, neuropathology, and clinical features were examined. Eighty-nine patients were included (median survival 10 months). APOE and PRNP codon 129 genotype distribution paralleled a healthy control group. APOE ε4 homozygosity was absent. Cerebrospinal fluid biomarkers were abnormal, but within a range as expected for classic AD, except for proteins 14-3-3, which were detectable in 42%. Thus, evidence of the existence of rpAD is accumulating. The APOE profile is intriguing, suggesting that this very rapid disease form might represent a distinct subtype of Alzheimer's disease.

Tauopathy in human and experimental variant Creutzfeldt-Jakob disease

Cerebral accumulation of hyperphosphorylated tau (phospho-tau) occurs in several neurodegenerative conditions including Alzheimer disease. In prion diseases, phospho-tau deposition has been described in a rare genetic form, Gerstmann-Sträussler-Scheinker disease, but is not considered part of the neuropathological picture of Creutzfeldt-Jakob disease. Aim of this study was to investigate whether changes related to phospho-tau accumulation are present in the brain of patients with variant Creutzfeldt-Jakob disease (vCJD) that shares with Gerstmann-Sträussler-Scheinker disease abundant prion protein (PrP) deposition in amyloid form. The analysis was extended to experimental mouse models of vCJD. We detected a large number of phospho-tau-immunoreactive neuritic profiles, often clustered around PrP amyloid deposits, not only in the cerebral cortex, but also in the cerebellum of all vCJD patients examined, in the absence of Abeta. Although less constantly, phospho-tau was localized in some perikaria and dendrites. The biochemical counterpart was the presence of phospho-tau in the detergent-insoluble fraction of cerebral cortex. Phospho-tau-immunoreactive neuronal profiles were also found in association with PrP deposits in mouse models of vCJD. These findings suggest that the abnormal forms of PrP associated with vCJD trigger a tauopathy, and provide a paradigm for the early stages of tau pathology associated with cerebral amyloidoses, including Alzheimer disease.

Creutzfeldt-Jakob disease with slow progression. A mimickry of progressive supranuclear palsy

Sporadic Creutzfeldt-Jakob disease (sCJD) does not always present with typical clinical signs, such as myoclonus in association with periodic sharp-wave complexes. We present a 67-year old female patient with initial falls and vertical gaze palsy, suggesting the diagnosis of Progressive Supranuclear Palsy (PSP). EEG and MRI were not contributory. Typical clinical and paraclinical CJD signs were only seen after 17 months. The diagnosis was confirmed by autopsy. - CJD can be a neurodegenerative chameleon. The present case adds to the scare literature of slowly evolving CJD mimicking Parkinsonism related to tauopathies.

Frontotemporal dementia, motor neuron disease and tauopathy: clinical and neuropathological study in a family

We report a familial disorder occurring in three patients that presented as frontotemporal dementia (FTD). A neuropathological study was performed in a 58-year-old patient, who developed FTD 2 years prior to the onset of motor neuron disease (MND), and died at age 62. Lesions indicative of associated MND were observed: neuronal loss in the anterior horns of the spinal cord, Bunina bodies, axonal spheroids, degeneration of the pyramidal tracts, and of FTD: decreased neuronal density and laminar microvacuolation of layers II and III in the frontal and temporal cortex. Ubiquitin-only-immunoreactive changes were found in the spinal cord and medulla, but were absent from the temporal and frontal cortex. There were also widespread deposits of various neuronal and glial inclusions containing abnormally phosphorylated tau protein, the Western blotting pattern of which was characterized by two major bands of 64 and 69 kDa. There were no abnormalities of the entire coding sequences of microtubule-associated protein tau (MAPT) and copper-zinc superoxide dismutase (SOD(1)) genes. Our results suggest that FTD associated with MND can be caused by a larger spectrum of neuropathological lesions than commonly accepted.

Compassionate use of quinacrine in Creutzfeldt–Jakob disease fails to show significant effects

Quinacrine has been reported as an antiprion agent and proposed as an immediately applicable treatment for Creutzfeldt–Jakob disease (CJD). The authors report the results of an open compassionate procedure to which 32 CJD patients had access. In some genotypic subgroups, a slight but nonsignificant increase in survival was observed, likely due to biased inclusion of long-term surviving patients. There was no pathologic evidence of a beneficial effect of quinacrine treatment.

Very early onset AD with a de novo mutation in the presenilin 1 gene (Met 233 Leu)

The authors describe a 28-year-old woman with histopathologically confirmed early onset Alzheimer disease characterized by severe frontal lobe involvement associated with a de novo mutation in the presenilin 1 gene (PSEN1).

Multiple sclerosis-associated retrovirus particles cause T lymphocyte-dependent death with brain hemorrhage in humanized SCID mice model

A retroviral element (multiple sclerosis-associated retrovirus, MSRV) defining a family of genetically inherited endogenous retroviruses (human endogenous retrovirus type W, HERV-W) has been characterized in cell cultures from patients with multiple sclerosis. Recently, MSRV retroviral particles or the envelope recombinant protein were shown to display superantigen activity in vitro, but no animal model has yet been set up for studying the pathogenicity of this retrovirus. In the present study, the pathogenicity of different sources of MSRV retroviral particles has been evaluated in a hybrid animal model: severe combined immunodeficiency (SCID) mice grafted with human lymphocytes and injected intraperitoneally with MSRV virion or mock controls. MSRV-injected mice presented with acute neurological symptoms and died within 5 to 10 days post injection. Necropsy revealed disseminated and major brain hemorrhages, whereas control animals did not show abnormalities (P <.001). In ill animals, reverse transcriptase-polymerase chain reaction (RT-PCR) analyses showed circulating MSRV RNA in serum, whereas overexpression of proinflammatory cytokines such as tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma was evidenced in spleen RNA. Neuropathological examination confirmed that hemorrhages occurred prior to death in multifocal areas of brain parenchyma and meninges. Further series addressed the question of immune-mediated pathogenicity, by inoculating virion to SCID mice grafted with total and T lymphocyte-depleted cells in parallel: dramatic and statistically significant reduction in the number of affected mice was observed in T-depleted series (P <.001). This in vivo study suggests that MSRV retroviral particles from MS cultures have potent immunopathogenic properties mediated by T cells compatible with the previously reported superantigen activity in vitro, which appear to be mediated by an overexpression of proinflammatory cytokines.

[Usefulness of molecular genetic analysis of the PRNP gene in patients with cerebellar ataxia: a new case of fatal familial insomnia]

We report the fifth French case of fatal familial insomnia, characterized by a mutation at codon 178 of prion protein gene and by heterozygoty (Met/Val) at codon 129. The clinical picture included cerebellar ataxia, dysautonomia and frontal lobe syndrome. Prion protein gene analysis was performed in order to support a diagnosis of Creutzfeldt-Jakob disease and assert the diagnosis of fatal familial insomnia. Neuropathologic analysis showed unusual changes including severe neuronal loss in the inferior olive and the dentate nucleus, and absence of obvious lesions in the thalamus. Moreover, spongiform changes were moderate in the superior temporal cortex and the occipital cortex. There was no spongiform change in frontal cortex. Abnormal prion protein (PrP(res)) was mainly evidenced in the parietal cortex. Molecular genetic study of the PRNP gene should be performed in patients who present with a cerebellar ataxia of equivocal origin.

MR spectroscopic pulvinar sign in a case of variant Creutzfeldt-Jakob disease

We report MR spectroscopic findings in a patient hospitalized with biopsy-proven variant Creutzfeldt-Jakob (vCJD) disease. N-acetyl aspartate was markedly decreased in the postero-medial part of the thalami (pulvinar) but was not diminished in the parieto-occipital white matter and cortical grey matter. These observations, which are in accordance with the pathological findings in this disease, suggest that MR spectroscopy, a highly sensitive method for the detection of subtle brain metabolic dysfunction, could be of interest for the diagnosis, prognosis and therapeutic follow-up of vCJD.

[Associations of patients and tissue banks]

Research dealing with tissue is more important to day than ever. Techniques of molecular genetics have indeed permitted the identification of a large number of new proteins that have now to be localised in the tissue and in the cell, in health and disease. This step has to be made in order to elaborate the adequate animal models in which new therapeutics can be tested. In France, however, human tissue samples have become difficult to obtain. Many factors contributed to this situation. Autopsies are now exceptionally performed. Doctors feel confident in their diagnosis and express rarely the need to control it. Families are opposed to post mortem more strongly than before, especially when the reasons for performing it can not be explained before the death of the patient. French law now makes the explicit consent of the patient mandatory before any research. This practically limits all post mortem investigations to those that had been planned before death. The possibility of giving tissue post mortem to allow research has to be publicised, particularly by associations of patients. The organisation that should manage to collect and store the samples at a large scale and over the whole country is lacking. Its structure is still discussed: should it be supported by the state itself, by private funding, possibly by the associations of patients themselves? Patients Associations are ready to play a crucial role: they realised that the present system was inefficient, they are presently trying to organise tissue banks; they will finally have to explain to their members why they should care for research, how they could help and how they will have to accept the absence of immediate spectacular results.

[The different varieties of autopsy. Proposal for a renewed medical and scientific autopsy]

Five main varieties of autopsies can be distinguished in France: the forensic pathology autopsy, medical and scientific autopsies, the "gift of corpse to the University", and the sanitary autopsy. The main rules and the shortcomings of French regulations ant its implementation are recalled. The disappearance of medical and scientific autopsies is of concern for three reasons: in some cases, the predictive value of clinical diagnosis is still poor and the proportion of unexpected findings that may have modified the patient therapy (20/25%) has remained unchanged for many years; autopsy is an important piece of the health watch, i.e. of public welfare; the modern post-genomic research needs tissue samples that often cannot be obtained by other means for ethical reasons. Numerous patients associations campaign for making easier the gift of organs for research purpose. The prerequisites for a renewing of autopsy, the modifications of regulations and practices that are required, the procedures to explain its importance in the hospital, among medical doctors and care givers, and in the society are considered.

[Neuropathology of the cerebral vessels of centenarians]

Neuropathological study of brain and brain vessels was performed in two series of 12 and 20 centenarians, focusing on the prevalence of small vessel lesions, infarction, Alzheimer's changes and mental status. These are discussed as a function of vascular risk factors. In the first series (12 cases), there was no correlation between the severity of small vessel lesions: hyalinosis (12/12), mineralisation (10/12), amyloid angiopathy (9/12), vascular risk factors (high blood pressure or diabetes), Alzheimer's lesions. However, there was a tendency for an association between amyloid angiopathy and high density of neurofibrillary tangles. In the second series (20 cases), small infarcts and lacunes were found in 9/20 cases, neurofibrillary tangles and diffuse deposits of A beta peptide were constant, senile plaques were very frequent (19/20). Five patients were demented (one vascular dementia, one Alzheimer dementia, and 3 mixed dementias). These data indicate that: 1) Lesions of the walls of small cerebral vessels do not seem linked to the vascular risk factors observed at the end of the life of centenarians. 2) Cerebral infarcts and lacunes are frequent in these patients, and are responsible, at least in part, for a high proportion of the cognitive dysfunctions. The study of larger series is needed for a better understanding of relationships between vascular and degenerative lesions in the oldest old.

Alpha-synuclein-immunoreactive deposits in human and animal prion diseases

Prion related disorders are associated with the accumulation of a misfolded isoform (PrPsc) of the host-encoded prion protein, PrP. There is strong evidence for the involvement of unidentified co-factors in the PrP to PrPsc conversion process. In this study, we show alpha-synuclein-immunoreactive deposits in the central nervous system of various prion diseases (sporadic, iatrogenic and new variant Creutzfeldt-Jakob diseases, and experimental scrapie of hamsters). alpha-Synuclein accumulated close to PrPsc deposits but we did not observe strict colocalization of prion protein and alpha-synuclein immunoreactivities particularly in PrPsc plaques. alpha-Synuclein is thought to be a key player in some neurodegenerative disorders, is able to interact with amyloid structures and has known chaperone-like activities. Our results, in various prion diseases, suggest a role for alpha-synuclein in regulating PrPsc formation.

Paradoxical phosphorylation of the serine 199 on tau proteins from young individuals

The microtubule-associated tau proteins are abnormally aggregated in many tauopathies. Phosphorylation modulates the functions of tau. The serine 199 residue of tau is abnormally phosphorylated at early and late stages of Alzheimer's disease. The presence of the phosphorylated Ser199 was investigated in autopsy-derived and biopsy-derived brain tissue samples from non-demented individuals. A paradoxical expression was found in the hippocampus of the youngest ones, in granule cells of the dentate gyrus and in pyramidal cells of the Ammon's horn, which are particularly prone to neurodegeneration in several tauopathies. The rate of positive cells decreased with age. These data emphasize the importance of the phosphorylation of the Ser199 residue of tau in ageing and susceptibility to neurodegeneration.

Autometallographic tracing of bismuth in human brain autopsies

For decades, drugs containing bismuth have been used to treat gastrointestinal disorders. Although a variety of adverse effects, including neurological syndromes, have been recorded, the biological/toxicological effects of bismuth ions are far from disclosed. Until recently, only quantitative assessments were possible, but resent research has made histochemical tracing of bismuth possible. The technique involves silver enhancement of bismuth crystallites by autometallography (AMG). In the present study, the localization of bismuth was traced by AMG in sections of paraffin-embedded brain tissue obtained by autopsy from 6 patients suffering from bismuth intoxication in a period ranging from 1975 through 1977. Tissue was analyzed at light and electron microscopical levels, and the presence of bismuth further confirmed by proton-induced x-ray emission (PIXE). Clinical data and bismuth concentrations in blood, cerebellum, and thalamus were measured by atomic absorption spectrophotometry (AAS) and are reported here. Histochemical analyses demonstrate that bismuth accumulated in neurons and glia cells in the brain regions examined (neocortex, cerebellum, thalamus, hippocampus). Cerebellar blood vessels stained most intensely. The PIXE and AAS data correlated with the histochemical staining patterns and intensities. At the ultrastructural level, bismuth was found to accumulate intracellularly in lysosomes and extracellularly in the basement membranes of some vessels.

[Autopsy]

The disappearance of autopsies is of concern in Neurology for three reasons: in some cases, such as degenerative diseases, the predictive value of clinical diagnosis is still poor; autopsy is, for Neurology, an important piece of the public health watch; the modern post-genomic research needs tissue samples that cannot be obtained by other means for ethical reasons. The main rules of autopsy in France, including the pitfalls of legislation, are recalled. The prerequisites for a renewing of autopsy, the modifications that are required, the procedure to explain its importance in the hospital, among neurologists, and in the society are considered.

Adaptation of the bovine spongiform encephalopathy agent to primates and comparison with Creutzfeldt-- Jakob disease: implications for human health

There is substantial scientific evidence to support the notion that bovine spongiform encephalopathy (BSE) has contaminated human beings, causing variant Creutzfeldt-Jakob disease (vCJD). This disease has raised concerns about the possibility of an iatrogenic secondary transmission to humans, because the biological properties of the primate-adapted BSE agent are unknown. We show that (i) BSE can be transmitted from primate to primate by intravenous route in 25 months, and (ii) an iatrogenic transmission of vCJD to humans could be readily recognized pathologically, whether it occurs by the central or peripheral route. Strain typing in mice demonstrates that the BSE agent adapts to macaques in the same way as it does to humans and confirms that the BSE agent is responsible for vCJD not only in the United Kingdom but also in France. The agent responsible for French iatrogenic growth hormone-linked CJD taken as a control is very different from vCJD but is similar to that found in one case of sporadic CJD and one sheep scrapie isolate. These data will be key in identifying the origin of human cases of prion disease, including accidental vCJD transmission, and could provide bases for vCJD risk assessment.

Neuropathological epidemiology of cerebral aging: a study of two genetic polymorphisms

We studied whether ApoE and -219 GT (ApoE promoter) polymorphism modulates neurofibrillary tangle (NFT) and senile plaque (SP) development in aging among 190 non-institutionalized individuals (mean age 79.5 years). Analysis revealed that the mean Braak stage was higher in epsilon4 allele carriers. Once individuals with Braak stage V were excluded (n = 5), relationships between NFT and the two genotypes studied were weak, whereas in epsilon4 allele carriers, the risk of SP was multiplied by 4 to 7 in four areas (CA1, subiculum, isocortex and entorhinal cortex). This association was more pronounced in subjects under 80 years and was also observed when analysis was restricted to Braak stages 0, I and II. Epsilon 2 allele carriers appeared to have fewer lesions but, due to limited numbers, this trend was not significant. In two regions (CA1, subiculum), the number of SP increased significantly for individuals who were homozygous for the T allele of -219 GT. However the association was no longer significant when controlling for ApoE epsilon4. It should be noted that the brain of elderly subjects carrying one epsilon4 allele may not undergo senile changes.

Outcome of patients with HIV-1-related cognitive impairment on highly active antiretroviral therapy

OBJECTIVE

To examine the impact of highly active antiretroviral therapy (HAART) on the outcome of HIV-1-related cognitive impairments using a neuropsychological (NP) battery to assess separately the psychomotor, executive function and memory fields.

DESIGN

A longitudinal study of HIV-1-infected patients based on serial NP tests in a Paris University Hospital.

METHODS

A group of 91 HIV-1-infected patients, of whom 47 were already taking HAART at their first NP examination, were initially categorized as cognitively impaired (n = 53) or non-impaired (n = 38) and underwent one to six serial NP batteries (mean follow-up 12.3+/-8.3 months). Generalized estimating equations (GEE) were used to evaluate performance in a given NP test according to the number of days on HAART.

RESULTS

Despite a 25% mortality rate among patients who had cognitive impairment at their first NP examination, GEE showed a positive relationship between the duration of HAART and cognitive performance. Performance in psychomotor tests (e.g. Purdue Pegboard dominant hand) improved continuously during the study period, while memory test performance (e.g. Grober and Buschke free recall) tended to reach a plateau.

CONCLUSIONS

HAART improves subcortical cognitive functions during the first year of treatment. Distinct neuropathological mechanisms appear to underlie psychomotor and memory dysfunctions in AIDS.

Dementia with Lewy bodies in a neuropathologic series of suspected Creutzfeldt-Jakob disease

Discriminating Creutzfeldt-Jakob disease (CJD) from dementia with Lewy bodies (DLB) may be clinically difficult to achieve. The authors describe 10 patients with DLB initially referred to the French Network of Human Spongiform Encephalopathies as having suspected CJD. In a series of 465 autopsied cases, DLB ranked second among degenerative alternative diagnoses to CJD. The authors analyzed the factors that contributed to misleading the diagnosis, and suggest that the detection of 14-3-3 protein in CSF may be useful to distinguish CJD from DLB.

[The anatomo-pathologic examination of the brain]

Guidelines for the neuropathological examination of the central nervous system (in adults) are proposed. They include the techniques used for the removal of the brain and spinal cord, the dissection of the skull, the removal of the brain, the fixation of the specimens, the sectioning of the brain, the choice of the blocks for histology, the usual staining methods and the main antibodies to be recommended for immunohistochemistry. Diagrams are given on which the lesions may be drawn and the samples, identified.

Age-related changes of neuronal counts in the human pedunculopontine nucleus

Cholinergic neurons in the basal forebrain and the upper brainstem undergo changes during aging and in dementia of the Alzheimer type, Parkinson's disease and progressive supranuclear palsy. Little is known about the effect of age on neurons in the tegmental pedunculopontine nucleus. Cholinergic neurons revealed by choline acetyltransferase immunohistochemistry were quantified in the brains of 20 subjects who died without neurological disorder between 28 and 101 years of age. A U-shaped relationship between cell counts and age was found, namely, a decrease in counts between 28 and 70, a minimum between 80 and 91 years of age, and, in four subjects aged 98-101 years counts comparable to those of subjects having died between 28 and 65 years. The findings suggest that the loss of cholinergic pedunculopontine nucleus neurons is not linear. In centenarians age-related neuronal decrease in pedunculopontine nucleus neurons may be slower or the stock of pedunculopontine nucleus neurons greater than in subjects dying earlier.

The extent of neurofibrillary pathology in perforant pathway neurons is the key determinant of dementia in the very old

Neurofibrillary pathology as found in Alzheimer's disease (AD) is also found in the normal elderly, suggesting that these changes may be part of the aging process. In this study, we assessed the densities and distribution of structures recognized by the monoclonal antibody (mAb) to phosphorylated tau (AT8) in the hippocampal formation and medial temporal isocortex of 19 centenarians. Of these, 4 cases were demented and 15 non-demented. AT8 immunoreactivity correlated with the global deterioration scale (GDS). The density of both intraneuronal neurofibrillary tangles (I-NFTs) and neuritic clusters (NCs) significantly correlated with the GDS in the layer II of the entorhinal cortex (r = 0.66, P = 0.005 and r= 0.611, P = 0.01, respectively). Density of I-NFTs in the subiculum (r = 0.491; P = 0.034) also correlated significantly. No other area was found to be statistically significant. Importantly, no correlation was found when demented and non-demented centenarian cases were analyzed separately, suggesting that the difference marks a fundamental shift between AD and non-demented individuals. This assertion is supported by the significantly higher densities of I-NFTs and NCs in the transentorhinal (P = 0.043 and P = 0.011, respectively) and layer II of the entorhinal cortex (P = 0.02 and P = 0.007, respectively), and I-NFTs in the subiculum (P < 0.001) and CAI (P = 0.011) in the demented group when compared with the non-demented cases. Granular diffuse deposits, an early stage parameter of the neurofibrillary pathology involving accumulation of non-fibrillar abnormally phosphorylated tau protein did not correlate with the GDS or between the two groups studied. This study, combining morphometric and confocal analyses, not only provides further evidence that, in the brains of patients with AD, the perforant pathway is highly sensitive to tau pathology but also that involvement is distinct from the changes of normal aging, even of the oldest old.

PrP immunohistochemistry: different protocols, including a procedure for long formalin fixation, and a proposed schematic classification for deposits in sporadic Creutzfeldt-Jakob disease

The use of immunohistochemistry on formalin-fixed and paraffin-embedded tissue has greatly improved the neuropathological diagnosis of Creutzfeldt-Jakob disease and the other subacute spongiform encephalopathies in human and animals. Two pitfalls of this technique, however, currently exist: low sensitivity after long formalin fixation and difficulties in interpreting some images. Here we review the protocols currently in use for the pretreatment of sections allowing PrP detection by immunohistochemistry. In addition, a technique useful after long formalin fixation is reported: enzymatic digestion with proteinase K (24 degrees C, 1/100 for 8 minutes) was employed in addition to the usual autoclaving (121 degrees C for 10 minutes) followed by formic acid (99% for 5 minutes) and 4M guanidine thiocyanate (4 degrees C for 2 hours). This allowed a substantial increase in the sensitivity of 3F4 immunohistochemistry on paraffin-embedded tissue, especially after prolonged formalin fixation. In addition, we suggest a simple method for classification of PrP immunolabelling in sporadic Creutzfeldt-Jakob disease that would allow easy comparisons.

Trends in mortality from sporadic Creutzfeldt-Jakob disease in France 1992-7

This study examined trends in mortality from sporadic Creutzfeldt-Jakob disease in France for 1992-7 by age, genotype at the codon 129 of the prion protein gene, and geographical area. Case ascertainment was based on notifications by neurologists, neuropathologists, and laboratories; 324 deaths from definite or probable Creutzfeldt-Jakob disease were registered during the study period. The yearly number of deaths increased significantly between 1992 and 1997. The rise was higher for older age groups. It was also higher in those who were homozygous for valine compared with other genotypes. Eighteen departments (geographical administrative areas) out of 95 showed a significant increase in the number of deaths from sporadic Creutzfeldt-Jakob disease. Intensive epidemiological surveillance is a likely explanation for the apparent increase in the number of sporadic cases of Creutzfeldt-Jakob disease over the 1992-7 period, particularly in older age groups and in departments with low mortality rate at the beginning of the study period. Intensive surveillance may also have led to a better identification of atypical valine homozygous cases.

Neuropathologic variants of sporadic Creutzfeldt-Jakob disease and codon 129 of PrP gene

OBJECTIVES

To determine the contribution of methionine/valine (Met/Val) polymorphism at codon 129 of the prion protein (PrP) gene in the neuropathologic pattern and mechanisms of lesion development in sporadic Creutzfeldt-Jakob disease.

BACKGROUND

Creutzfeldt-Jakob disease is a transmissible spongiform encephalopathy characterized by a conformational change of PrP and a variety of PrP deposits in the brain, some of which aggregate into amyloid plaques.

METHODS

The authors semiquantitatively assessed neuropathologic lesions and performed PrP immunolabeling in 70 patients (39 Met/Met, 11 Met/Val, 20 Val/Val) who had died in France between 1994 and 1998.

RESULTS

Met/Met cases (mild lesions mostly involving the occipital areas, low PrP load, few focal PrP nonamyloid deposits, no amyloid plaques) contrasted with Met/Val cases (marked lesions especially in the parahippocampal gyrus, high PrP load, numerous amyloid plaques) and with Val/Val cases (younger patients, longer course of disease: 11.5 +/- 3 months, and distinct neuropathology: severe lesions heavily involving the hippocampal formation and basal ganglia, high PrP load, numerous focal nonamyloid deposits, rare amyloid plaques). The course of Val/Val patients younger than age 55 was particularly long (19.9 +/- 7 months), and the isocortex bore the brunt of the pathology, suggesting a distinct variety.

CONCLUSIONS

Polymorphism at codon 129 modulates the phenotype of sporadic Creutzfeldt-Jakob disease. The Val genotype enhances the production of proteinase-resistant PrP, and the Met/Val genotype facilitates its aggregation into amyloid plaques.

Laminar specific loss of isocortical presenilin 1 immunoreactivity in Alzheimer's disease. Correlations with the amyloid load and the density of tau-positive neurofibrillary tangles

Presenilin 1 has been shown to be mutated in a high proportion of cases of familial Alzheimer's disease. Immunoreactive epitopes of the protein have been found mainly in neurones devoid of neurofibrillary tangles - an observation that has led to the conclusion that presenilin 1 could have a protective role. In this study, the relationship between deposits of Abeta peptide (both the 40 and 42 isoforms), tau positive neurofibrillary tangles and presenilin 1-positive neuronal profiles were analysed in three cases of presenilin 1 mutation, four cases of sporadic Alzheimer's disease and five controls. Immunohistochemistry was performed in a sample from the supramarginal gyrus. The proportion of volume occupied by the Abeta1-40 and Abeta1-42 deposits (amyloid load) was evaluated by a point-counting technique. Tau-positive neurofibrillary tangles, and presenilin 1-positive neuronal profiles were directly counted. The location of the lesions in the thickness of the cortex was recorded. The density of PS1-positive neuronal profiles in Alzheimer's disease cases was lower than in the controls. The deficit was significant only in the upper layers of the cortex. The density of presenilin 1 neuronal profiles was negatively correlated with Abeta1-40 and Abeta1-42 loads, and with the density of tau-positive neurofibrillary tangles. Multivariate analysis showed that the Abeta1-42 load was the best determinant of the decrease in presenilin 1-positive neuronal profiles. Presenilin 1-positive neurones appear to be lost rather than protected in the course of Alzheimer disease.

Diagnosis of Creutzfeldt-Jakob disease: effect of clinical criteria on incidence estimates

OBJECTIVE

To assess the effect of usage of three different versions of Creutzfeldt-Jakob disease (CJD) diagnostic criteria on estimates of CJD incidence.

METHODS

A total of 428 patients referred for suspected sporadic CJD between 1991 and 1997 were classified according to different criteria to be compared after analysis of medical records. Specificity, sensitivity, and positive and negative predictive values were calculated for each set of criteria in the subgroup of patients with a postmortem examination. Positive and negative predictive values of the clinical diagnosis were applied to cases without postmortem examination. Subsequently, the true number of cases of CJD among the referred cases was estimated.

RESULTS

By comparison with the French and European study criteria, the Masters' criteria showed higher sensitivity but lower specificity and positive predictive value. Comparison with an estimate of the true total number of CJD cases showed that Masters' criteria overestimated the incidence by 7%, whereas the French and the European study criteria led to an underestimate of 12%. Detection of the 14-3-3 protein in CSF, considered as an additional diagnostic criterion for clinically probable CJD, resulted in a slight increase in the estimated incidence when the French or European study criteria were applied.

CONCLUSIONS

Different diagnostic criteria could lead to an under- or overestimation of the true incidence of CJD. Therefore, comparisons of CJD incidence in different countries should rely on diagnostic classifications using identical criteria. Taking into account 14-3-3 protein detection as a criterion for probable CJD will result in a small increase in the estimated CJD incidence.

Similar subcortical pattern of cognitive impairment in AIDS patients with and without dementia

The aim of this study was to develop a series of neuropsychological tests that define the cortical and subcortical features of cognitive impairment and the characteristics of memory in demented and mildly cognitively impaired AIDS patients. We attempted to establish a usable method to assess and determine the type and degree of cognitive impairment in individual AIDS patients. We examined 53 patients without central nervous system opportunistic infections. A short battery included two scales of global efficiency (the Mattis dementia rating scale and the Mini Mental State Examination), a psychomotor speed test, an executive control assessment and explicit memory evaluation. Patients were categorized into four groups based on their score on both the Mattis dementia rating scale and the DSM-IV criteria: (1) asymptomatic; (2) having AIDS without cognitive impairment; (3) having AIDS with mild cognitive impairment; and (4) having AIDS dementia. Patients with mildly impaired cognition demonstrated slowed thinking, abnormal initiation and conceptualization, and memory impairment. AIDS dementia patients had slower motor activity and memory recall was more severely affected. The short neuropsychological battery was able to characterize modified cognitive performances in both severely and mildly cognitively impaired AIDS patients. The subcortical pattern of the memory disorder was obvious, regardless of the degree of cognitive impairment.

[Research on multiple sclerosis and tissue banks]

Tissue banks are of major importance in research on human tissues, in particular as regards the furthering of our knowledge on multiple sclerosis (MS). Individuals who wish to make a 'donation of their brain' for autopsy, or pathologists in possession of biopsy specimens that have not been utilized for diagnosis provide the necessary material for investigation by research teams. In addition to their technical aspects, brain tissue banks provide information and aid in promoting research. Their functioning, usually supported by patient associations, has encountered certain difficulties. At present, it is challenged by a decrease in the number of autopsies.

[Alzheimer's disease: lesions and their progression]

Alzheimer disease appears to be a stereotyped mode of reaction of the central nervous system to various types of aggression such as different mutations involving various proteins, trisomy 21 or repeated head trauma as in dementia pugilistica. Rather than a disease, it appears to be a clinicopathological syndrome due to various causes. Lesions may be considered under 3 headings: neurofibrillary pathology, A beta peptide deposits and loss (neuronal and synaptic). Neurofibrillary pathology includes the neurofibrillary tangle, the crown of the senile plaque and the neuropil threads. All those lesions are characterized by the same ultrastructure--i.e. the accumulation of paired helical filaments--and the same immunohistochemistry: they are labelled by antibodies directed against the tau proteins. The amyloid deposits, present in the core of the senile plaque and in the vascular walls, are made of a 40 to 42 amino-acids long peptide, named A beta, derived from the amyloid precursor protein (APP). Antibodies directed against the A beta peptide also label diffuse deposits that are devoid of the tinctorial affinities and of the biochemical properties of amyloid substances. Those diffuse deposits are insufficient to cause dementia since they may be observed in high density in aged people without intellectual deterioration. Neuronal loss occurs after neurofibrillary pathology. The role of the synaptic pathology remains discussed. Besides tau proteins, A beta peptide and APP, several other proteins may play an important role: apolipoprotein E which could act as a chaperone protein, inducing or facilitating the formation of amyloid, presenilins 1 and 2, mutated in some cases of familial Alzheimer disease, alpha-synuclein which is present in the Lewy bodies found in Parkinson disease and in dementia with Lewy bodies. The A beta deposits are diffusely distributed in the cerebral cortex; the neurofibrillary changes have a hierarchical distribution. The progression of the neurofibrillary pathology in the various cortical areas follow a stereotyped sequence that may help to grade the severity of the disease. Progression may take decades. The relations between aging and Alzheimer disease are still poorly understood. Frequency of Alzheimer type lesions in old people could suggest that they are the inevitable burden of age, but this has been discussed.

Preservation of midbrain catecholaminergic neurons in very old human subjects

Parkinson's disease is characterized by a progressive degeneration of dopaminergic neurons in the midbrain, yet the cause of this neuronal loss is still unknown. It has been hypothesized that Parkinson's disease could be the consequence of accelerated ageing. In order to reveal a possible common process during ageing and Parkinson's disease neurodegeneration, catecholaminergic neurons of five anatomical regions of the brainstem (substantia nigra, central grey substance, ventral tegmental area, peri- and retrorubral area, and locus coeruleus) have been quantified using immunohistochemical staining for tyrosine hydroxylase (TH) on regularly spaced sections, between the rostral and caudal poles of the mesencephalon and in the rostral pole of the pons, in post-mortem samples of 21 control subjects who died at ages 44-110 years. No statistically significant loss of TH positive neurons was observed in the older subjects, either in the substantia nigra or in the other midbrain regions that are known to degenerate to a lesser degree in Parkinson's disease. Furthermore, in the later regions no neuronal loss was observed from age 44 to 80 years, indicating that this result is not dependent on the inclusion of 'supernormal' very old people. These results suggest that from age 44 to 110 years, ageing in control adults is not, or is scarcely, accompanied by catecholaminergic cell loss in the midbrain and hence Parkinson's disease is probably not caused by an acceleration of a degenerative process during ageing.

[Miyoshi distal myopathy: specific signs and incidence]

We report 21 French patients (12 males and 9 females), presenting a distal myopathy of Miyoshi type. The main clinical features of these patients were 1) onset in late adolescence or early adulthood (mean age: 20.3 years), 2) early and predominant involvement of the posterior compartment muscles of legs, 3) marked elevation of serum CK (from 10 to 50 times the normal value), 4) dystrophic features with a necrotic regeneration pattern without vacuole in muscle biopsy. All cases were sporadic and a consanguinity of parents was found in five cases. The clinical course was relatively mild: twelve patients could walk without aid; However four patients were severely disabled. Four patients were initially considered as having polymyositis; corticosteroids and immunosuppressive drugs were always inefficient. A genetic linkage to chromosome 2 was ascertained in five cases. In our experience the Miyoshi distal myopathy is the most common form of distal myopathy, particularly in young patients.

Overexpression of BCL-2, BCL-X, and BAX in primary central nervous system lymphomas that occur in immunosuppressed patients

In contrast to primary central nervous system lymphomas (PCNSLs) that occur in immunocompetent patients, most of those that occur in immunosuppressed patients are associated with Epstein-Barr virus (EBV). BCL-2-related proteins either block or promote cell death, forming homo- or heterodimers with each other. LMP-1, EBV latent protein, has been shown to upregulate BCL-2 and BCL-XL. This observation suggests that these proteins may be involved in the transformation process of EBV-infected cells. Twenty-three cases of PCNSLs were studied: 12 of the patients were immunosuppressed, and 11 were immunocompetent. For all cases, we collected clinical information, histologic data, and immunophenotype and tested for the presence of EBV (EBER-1, LMP-1). Apoptosis was assessed by the TdT-mediated dUTP-biotin nick-end labeling method and quantified by image analysis. In three cases, electron microscopy was performed. The BCL-2 family proteins (BCL-2, BCL-X, MCL1, and BAX) and p53 expression were studied by immunohistochemistry on paraffin slides. All cases were classified as diffuse large B-cell lymphomas. PCNSLs in immunosuppressed patients were characterized by EBV association, necrosis, important gliosis, and numerous macrophages. There was no significant difference between the two groups regarding the TdT-mediated dUTP-biotin nick-end labeling staining (P = .08). In contrast, PCNSLs in immunosuppressed patients were shown to express high levels of BCL-2, BCL-X, and BAX in more than 80% of tumor cells in 7, 10, and 11 cases, respectively. In immunocompetent patients, only one case showed a high level of BCL-2 expression in more than 80% of the cells, whereas BCL-X and BAX were overexpressed in two cases. These differences are significant (P < .05). In contrast, there was no significant difference between the two groups in MCL-1 expression. Besides EBV association and necrosis, PCNSLs related to immunosuppression are characterized by an overexpression of BCL-2-related proteins, without dramatically modifying their susceptibility for apoptosis.

Microglia, amyloid and dementia in alzheimer disease. A correlative study

To elucidate the role of microglia in Alzheimer's disease, a clinicopathological study was performed involving 26 cases, the mental status of which had been studied pre mortem by the Blessed test score (BTS). We measured the volume density of CD 68 immunoreactive (IR) microglia, congophilic plaques and Abeta deposits, and the numerical density of neurofibrillary tangles (NFT) in a sample of Area 9 (middle frontal gyrus). Dementia was significantly correlated only with the volume density of Abeta deposits and the numerical density of NFT. The volume densities of microglia and congophilic plaques were strongly correlated. With the intellectual status used as a time scale, IR microglia and amyloid deposits appeared almost simultaneously at an early stage in the pathological cascade and decreased, whereas Abeta and NFT were still accumulating. The intellectual deficit seemed to be more significantly related to the latter two lesions than to the microglia-amyloid complex, that was visible at an earlier stage (around BTS = 15).

MS-8209, an amphotericin B analogue, delays the appearance of spongiosis, astrogliosis and PrPres accumulation in the brain of scrapie-infected hamsters

The histopathological response of scrapie-infected hamsters treated at the late stage of the infection with an "anti-scrapie" drug, a polyene macrolide antibiotic designated MS-8209, was evaluated in the brain. The results showed that (1) MS-8209 prolonged significantly the incubation time of the experimental disease, (2) MS-8209 delayed the appearance of spongiosis and astrogliosis in the brain, (3) immunodetection of abnormal prion protein and glial fibrillary acidic protein was significantly reduced in the central nervous system. In addition, this report indicates that polyene antibiotics markedly delay the development of the classical brain lesions that result from scrapie infection.

[Multiple sclerosis: one or several diseases?]

The various clinical courses of multiple sclerosis (relapsing-remitting, primary progressive, secondary progressive, progressive-relapsing) are likely related to different severity or distribution of the main lesions that constitute the plaques (inflammation, demyelination, axonal injury and loss, necrosis). They might lead to different therapeutic approaches. Some cases of the other clinico-radiological or clinico-pathological variants (pseudo-tumoral, concentric sclerosis of Baló, acute disseminate encephalomyelitis, Devic's neuromyelitis optica) obviously share similar mechanisms with multiple sclerosis. Other cases are, on the contrary, linked to different diseases. Do the variants of multiple sclerosis could be the consequence of different diseases? This is, today, a highly speculative conjecture. The prevalent hypothesis suggests that the clinico-pathological heterogeneity of multiple sclerosis is linked to the variability of the reaction of the nervous tissue to an initial injury. This different vulnerability, that depends on unknown factors, would explain the variants of the disease.

Incubation period of Creutzfeldt-Jakob disease in human growth hormone recipients in France

OBJECTIVE

To estimate the statistical distribution of the incubation period of Creutzfeldt-Jakob disease (CJD) in human growth hormone (hGH) recipients in France.

BACKGROUND

Published papers suggest that the median incubation period of hGH-related CJD is approximately 15 years, but there are as yet no statistical data that support this assertion.

METHODS

Of the 1,361 hGH recipients who were included in this study, 55 had developed CJD at the time of the study. Individual data on hGH treatment history were available. Different mathematical models were used to estimate the statistical distribution of the incubation period. One main feature of the models was to take into account the occurrence of future CJD cases.

RESULTS

Models showed that the mean incubation period was 9 to 10 years, and the 95th percentile of the distribution was 15 to 16 years. Data and models indicated that the incubation period was significantly shorter in homozygotes at codon 129 of the prion protein gene than in heterozygotes.

CONCLUSIONS

The short mean incubation period of CJD in French hGH recipients may be due to high infectivity in hormone lots. Estimates of the 95th percentile indicate that the number of hGH-related CJD cases may continue to increase in the coming years.