Lack of association between an estrogen receptor 1 gene polymorphism and Parkinson's disease with dementia

OBJECTIVE

To test for an association between an estrogen receptor 1 (ESR1) gene polymorphism and Parkinson's disease with dementia (PDD) in Finnish subjects.

SUBJECTS AND METHODS

Forty-one clinically demented and pathologically confirmed PDD patients and 59 cognitively intact aged individuals with normal neuropathology were genotyped for the ESR1 PvuII polymorphism.

RESULTS

We found no significant differences in the genotype or allele frequencies when the PDD patients were compared with the controls. Nor were there any significant differences in these frequencies when the PDD patients with coexisting Alzheimer's disease pathology were compared with the control group.

CONCLUSION

We failed to demonstrate an association between dementia-associated PD and the ESR1 PvuII polymorphism in Finnish subjects.

Course of minimal dementia and predictors of outcome

BACKGROUND

Previous studies have indicated that not all subjects who meet the CAMDEX criteria of 'minimal dementia' progress to dementia. In the present study, predictors of outcome in minimally demented subjects were tested.

METHODS

Forty-five subjects with minimal dementia who were participating in a population-based study were followed-up for on average 2.3 years. Variables tested as predictors of outcome were age, the apolipoprotein E (APOE) genotype, and the baseline scores on the MMSE, CAMCOG memory subscale, and fluency. Depression at baseline was tested as a predictor of reversible minimal dementia.

RESULTS

At follow-up, minimal dementia turned out to be reversible in 11 subjects (24%), and persistent in ten subjects (22%). Twenty-four subjects (53%) had become demented. Predictors of outcome in multivariate analyses were age, score on the CAMCOG memory subscale, and the APOE genotype. Depression was not associated with reversible minimal dementia.

CONCLUSIONS

Subjects who meet the CAMDEX criteria of minimal dementia form a heterogenous group with respect to clinical outcome. Age, the score on the CAMCOG memory subscale, and the APOE genotype can improve predictive accuracy in these subjects.

Polymorphisms in the tau gene in sporadic frontotemporal dementia and other neurodegenerative disorders

The tau gene on chromosome 17 is fundamental in the pathogenesis of a number of neurodegenerative disorders. Mutations in tau are found in familial frontotemporal dementia (FTD) and the A0/A0 genotype associated with progressive supranuclear palsy (PSP). This study investigates the hypothesis that polymorphisms in the tau gene are associated with sporadic FTD. Western Australian populations of patients with sporadic frontotemporal dementia, PSP, Alzheimer's disease (AD), Huntington's disease (HD) and normal controls were studied. A new method was developed using fluorescently labelled probes to determine polymorphisms in the GT repeat region of intron 9. The A0/A0 genotype was found in 95% of PSP patients (n=20), 58.3% of FTD patients (n=48), 60.8% of AD patients (n=52), 75% of HD patients (n=40), and 75% of normal controls (n=40). None of these differences in genotype frequency were found to be significant by the Fisher exact test (P > 0.05). There were no significant differences in the frequencies of A0/A3 and A0/A1 haplotypes. We have not observed a significant increase in the A0/A0 genotype frequency in sporadic frontotemporal dementia suggesting that this polymorphism is unlikely to be related to the development of this condition. Furthermore, we have observed an increase in the A0/A0 genotype in PSP which did not reach statistical significance, suggesting that there may be population differences in the role of genetic factors in conferring risks to neurodegenerative disorders. Our work does not exclude that tau may interact with other genetic factors.

Extract of Yi Zhi Fang improves learning and memory behaviours of mice and its possible mechanisms

The effects of Yi Zhi Fang extract (YZF) on learning and memory performances were investigated in mice using passive avoidance tasks. Oral administration of YZF improved learning and memory disorders induced by chemicals in both normal and senile mice. The acetylcholine (Ach) concentration, the muscarinic Ach receptors (M-R) and the monoamine oxidase B (MAO-B) activities were analysed by a radioimmunoassay, a radioligand receptor binding assay and UV spectrophotometry, respectively, using senile decapitated mice. The oral administration of YZF to the senile mice increased the M-R concentration, while the concentration of Ach and the activity of MAO-B decreased in senile mice brains. From these results it is evident that YZF promotes the function of the central cholinergic system and inhibits the activity of MAO-B in mice brains resulting in an enhancement of learning and memory.

Substantial sulfatide deficiency and ceramide elevation in very early Alzheimer's disease: potential role in disease pathogenesis

In addition to pathology in the gray matter, there are also abnormalities in the white matter in Alzheimer's disease (AD). Sulfatide species are a class of myelin-specific sphingolipids and are involved in certain diseases of the central nervous system. To assess whether sulfatide content in gray and white matter in human subjects is associated with both the presence of Alzheimer's disease (AD) pathology as well as the stage of dementia, we analyzed the sulfatide content of brain tissue lipid extracts by electrospray ionization mass spectrometry from 22 subjects whose cognitive status at time of death varied from no dementia to very severe dementia. All subjects with dementia had AD pathology. The results demonstrate that: (i) sulfatides were depleted up to 93% in gray matter and up to 58% in white matter from all examined brain regions from AD subjects with very mild dementia, whereas all other major classes of lipid (except plasmalogen) in these subjects were not altered in comparison to those from age-matched subjects with no dementia; (ii) there was no apparent deficiency in the biosynthesis of sulfatides in very mild AD subjects as characterized by the examination of galactocerebroside sulfotransferase activities in post-mortem brain tissues; (iii) the content of ceramides (a class of potential degradation products of sulfatides) was elevated more than three-fold in white matter and peaked at the stage of very mild dementia. The findings demonstrate that a marked decrease in sulfatides is associated with AD pathology even in subjects with very mild dementia and that these changes may be linked with early events in the pathological process of AD.

Significance and mechanism of Alzheimer neurofibrillary degeneration and therapeutic targets to inhibit this lesion

Abnormally hyperphosphorylated tau which is the major protein subunit of paired helical filaments (PHF)/neurofibrillary tangles is the pivotal lesion in Alzheimer disease (AD) and related tauopathies. The cosegregation of tau mutations with disease in inherited cases of frontotemporal dementia has confirmed that abnormalities in this protein can be a primary cause of neurodegeneration. Unlike normal tau that promotes assembly and maintains the structure of microtubules, the abnormally hyperphosphorylated protein sequesters normal tau, MAP1 and MAP2 and consequently disassembles microtubules. The abnormal hyperphosphorylation also promotes the self assembly of tau into tangles of PHF. The hyperphosphorylation of tau in AD is probably due to a protein phosphorylation/dephosphorylation imbalance produced by a decrease in the activity of protein phosphatase (PP)-2A and increase in the activities of tau kinases which are directly or indirectly regulated by PP-2A. Two of the most promising pharmacologic therapeutic approaches to AD are (1) the development of drugs that can inhibit the sequestration of normal MAPs by the abnormally hyperphosphorylated tau, and (2) the development of drugs that can reverse the abnormal hyperphosphorylation of tau by correcting the protein phosphorylation/dephosphorylation imbalance.

Early inflammation and dementia: a 25-year follow-up of the Honolulu-Asia Aging Study

Inflammatory responses are associated with cardiovascular disease and may be associated with dementing disease. We evaluated the long-term prospective association between dementia and high-sensitivity C-reactive protein, a nonspecific marker of inflammation. Data are from the cohort of Japanese American men who were seen in the second examination of the Honolulu Heart Program (1968-1970) and subsequently were reexamined 25 years later for dementia in the Honolulu-Asia Aging Study (1991-1996). In a random subsample of 1,050 Honolulu-Asia Aging Study cases and noncases, high-sensitivity C-reactive protein concentrations were measured from serum taken at the second examination; dementia was assessed in a clinical examination that included neuroimaging and neuropsychological testing and was evaluated using international criteria. Compared with men in the lowest quartile (<0.34mg/L) of high-sensitivity C-reactive protein, men in the upper three quartiles had a 3-fold significantly increased risk for all dementias combined, Alzheimer's disease, and vascular dementia. For vascular dementia, the risk increased with increasing quartile. These relations were independent of cardiovascular risk factors and disease. These data support the view that inflammatory markers may reflect not only peripheral disease, but also cerebral disease mechanisms related to dementia, and that these processes are measurable long before clinical symptoms appear.

BRICHOS: a conserved domain in proteins associated with dementia, respiratory distress and cancer

A novel domain (the BRICHOS domain) of approximately 100 amino acids has been identified in several previously unrelated proteins that are linked to major diseases. These include BRI(2), which is related to familial British and Danish dementia (FBD and FDD); Chondromodulin-I (ChM-I), related to chondrosarcoma; CA11, related to stomach cancer; and surfactant protein C (SP-C), related to respiratory distress syndrome (RDS). In several of these, the conserved BRICHOS domain is located in the propeptide region that is removed after proteolytic processing. Experimental data suggest that the role of this domain could be related to the complex post-translational processing of these proteins.

Ubiquitin-positive neuronal and tau 2-positive glial inclusions in frontotemporal dementia of motor neuron type

Attempts at classification of fronto-temporal dementias have not yet been completely successful. We report ten cases of sporadic fronto-temporal dementia (FTD) with ubiquitin-positive neuronal inclusions in cortex or in motor neurons in brain stem or spinal cord, which may contribute to the classification of FTD. Marked variation in clinical presentation as well as in pathological findings was the rule in all cases. Dementia was a prominent feature. Only one case had clinical features suggestive of motor neuron disease. Three of four younger onset cases displayed an especially severe atrophy of the temporal lobes, the basal ganglia and the substantia nigra. This contrasted with the other seven cases in which the fronto-temporal atrophy and changes in basal ganglia and substantia nigra were variable and sometimes mild. In addition to the presence of ubiquitin-reactive, but tau-and silver impregnation-negative neuronal inclusions, all cases demonstrated tau 2-positive glial inclusions, similar to those recently reported in three motor neuron disease cases with dementia. The glial inclusions were not visible with antibody to tau 1. Reaction with antibody to alpha-synuclein was invariably negative. If the combination of ubiquitin-positive neuronal and tau 2-positive glial inclusions is found to be consistently present in FTD of motor neuron type, this feature will provide a firmer basis for this diagnosis than previously available.

Contrasting genotypes of the tau gene in two phenotypically distinct patients with P301L mutation of frontotemporal dementia and parkinsonism linked to chromosome 17

Association between clinical characteristics and types of the tau gene mutation has been observed in frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17). P301L mutation seldom causes parkinsonism as a leading symptom; instead it usually causes personality changes with aggressiveness and disinhibition. We experienced two patients of FTDP-17 from separate families (designated as patient 1 from family 1 and patient 2 from family 2). They had P301L mutation in common. However, their phenotypes were distinct from each other. Aggressive behaviors and disinhibition were the main symptoms in patient 1, whereas parkinsonism was the most prominent feature in patient 2. Their genotypes of the tau gene were different at three sites, i. e. in exon 6, in intron segment before exon 10, and in exon 13, though they do not bring amino acid change. Patient 1 had more prevalent C/C, C/C, and rare T/C respectively. Patient 2 had less prevalent T/T, A/A, and more prevalent T/T respectively. These findings suggest two things. Firstly, they do not share a common founder for P301L mutation. Secondly, either of the two less prevalent genotypes observed in patient 2 may be the factor to modify the phenotype of P301L mutation into those unusual clinical features with prominent parkinsonism. Accumulation of information as to phenotype-genotype association will settle this hypothesis.

Striatal dopamine transporter and extrapyramidal symptoms in frontotemporal dementia

OBJECTIVE

To evaluate dopaminergic function in patients with frontotemporal dementia (FTD).

BACKGROUND

Patients with FTD not only show typical behavioral and cognitive deficits but extrapyramidal symptoms, most commonly rigidity and akinesia. The pathophysiologic basis of these symptoms is unclear.

METHODS

The authors investigated 12 patients (mean age = 67.2 +/- 7.2 years, range = 52 to 76 years) with FTD using a cocaine analogue [11C]CFT as a ligand with PET. The results were compared with those of 15 healthy control subjects (mean age = 49.7 years, range = 23 to 70 years) using analysis of covariance to adjust for difference in age. A dynamic 80-minute study was performed, and (region - cerebellum)/cerebellum ratios were calculated for the caudate nucleus and putamen. The severity of extrapyramidal symptoms was evaluated by the motor part of the Unified Parkinson's Disease Rating Scale (UPDRS).

RESULTS

The mean age-adjusted [11C]CFT uptake value in the putamen in patients with FTD was reduced to 82% of the control value (p = 0.017), with the corresponding figure for caudate [11C]CFT uptake being 86% (p = 0.007). The motor UPDRS scores of patients with FTD showed a negative correlation with [11C]CFT uptake in both the putamen (r = -0.76, p = 0.004) and caudate nucleus (r = -0.70, p = 0.01).

CONCLUSIONS

Nigrostriatal dopaminergic function is impaired in FTD, with the projections to the putamen and caudate nucleus being affected to the same degree. The reduction in the binding of the dopamine transporter ligand [11C]CFT is related to the severity of extrapyramidal symptoms of the patients.

[Use of positron emission tomography in psychiatry]

For the past years, substantial amount of experimental data has been published on the use of positron emission tomography in different psychiatric disorders. The different PET methods, which evaluate the whole-brain or regional metabolism, tissue perfusion or receptor density may help to identify the disorder specific changes in brain function and also better understand the underlying pathophysiology. In the clinical practice, PET plays an important role in the diagnosis and differential diagnosis of dementias and, presumably, in the near future the PET technique will be also extensively used in the clinical examination of other psychiatric disorders.

Alternative transcripts of presenilin-1 associated with frontotemporal dementia

We have analyzed the expression of Alzheimer's disease-associated presenilin 1 (PS1) in various neurodegenerative disorders. Western blotting identified PS1 N- and C-terminal fragments similarly in the cortex of controls, Parkinson, Huntington and schizophrenia subjects. Additional PS1 immunoreactive species of 42 and 46 kDa were present in six out of seven cases of sporadic frontotemporal dementia (FTD) and these were particularly prominent in two cases. RT-PCR analysis using nested primers showed the presence of PS1 gene products with deletions within the exon 4-8 region. Our results suggest that alternative transcription of PS1 may be associated with FTD.

Weight loss and metabolic changes in dementia

Weight loss is common in elderly people with dementia, particularly those with Alzheimer s disease, and feeding difficulties are major issues in their care in the later stages of their disease. This review summarizes data from cross-sectional and longitudinal studies of weight changes with dementia, physiologic aspects of the metabolic and nutritional changes in dementia, and treatment strategies to minimize weight loss.

Tau and alpha-synuclein pathology in amygdala of Parkinsonism-dementia complex patients of Guam

Amyotrophic lateral sclerosis/parkinsonism-dementia complex (ALS/PDC) is a progressive neurodegenerative disorder of Chamorro residents of Guam and the Mariana Islands, characterized by abundant neuron loss and tau neurofibrillary pathology similar to that observed in Alzheimer's disease (AD). A variety of neurodegenerative diseases with tau pathology including ALS/PDC also have alpha-synuclein positive pathology, primarily in the amygdala. We further characterized the tau and alpha-synuclein pathology in the amygdala of a large series of 30 Chamorros using immunohistochemical and biochemical techniques. Tau pathology was readily detected in both affected and unaffected Chamorros. In contrast, alpha-synuclein pathology was detected in 37% of patients with PDC but not detected in Chamorros without PDC or AD. The alpha-synuclein aggregates often co-localized within neurons harboring neurofibrillary tangles suggesting a possible interaction between the two proteins. Tau and alpha-synuclein pathology within the amygdala is biochemically similar to that observed in AD and synucleinopathies, respectively. Thus, the amygdala may be selectively vulnerable to developing both tau and alpha-synuclein pathology or tau pathology may predispose it to synuclein aggregation. Furthermore, in PDC, tau and alpha-synuclein pathology occurs independent of beta-amyloid deposition in amygdala thereby implicating the aggregation of these molecules in the severe neurodegeneration frequently observed in this location.

Effects on splicing and protein function of three mutations in codon N296 of tau in vitro

Three Mutations were recently reported in the same codon (N296) in exon 10 of the tau gene. Two of these mutations, N296N and N296H, lead to a clinical syndrome similar to autosomal dominant fronto-temporal dementia with Parkinsonism linked to chromosome 17. In contrast the third mutation, delN296, gives rise to atypical progressive supranuclear palsy in individuals homozygous for the mutation, but in heterozygous individuals this mutation is incompletely penetrant and associated with a phenotype similar to idiopathic Parkinson's disease. Functional assays were employed to determine the effects of these mutations on alternative splicing of exon 10, on microtubule assembly and self-aggregation of recombinant tau protein. We demonstrate that these mutations exhibit a spectrum of potentially pathogenic changes in tau function, and provide insight into the possible cause of the incompletely penetrant phenotype of the delN296 mutation.

Alternative transcripts of presenilin-1 associated with frontotemporal dementia

We have analyzed the expression of Alzheimer's disease-associated presenilin 1 (PS1) in various neurodegenerative disorders. Western blotting identified PS1 N- and C-terminal fragments similarly in the cortex of controls, Parkinson, Huntington and schizophrenia subjects. Additional PS1 immunoreactive species of 42 and 46 kDa were present in six out of seven cases of sporadic frontotemporal dementia (FTD) and these were particularly prominent in two cases. RT-PCR analysis using nested primers showed the presence of PS1 gene products with deletions within the exon 4-8 region. Our results suggest that alternative transcription of PS1 may be associated with FTD.

Hypersensitive mousetraps, alpha1-antitrypsin deficiency and dementia

Alpha(1)-antitrypsin functions as a "mousetrap" to inhibit its target proteinase, neutrophil elastase. The common severe Z deficiency variant (Glu(342)-->Lys) destabilizes the mousetrap to allow a sequential protein-protein interaction between the reactive-centre loop of one molecule and beta-sheet A of another. These loop-sheet polymers accumulate within hepatocytes to form inclusion bodies that are associated with juvenile cirrhosis and hepatocellular carcinoma. The lack of circulating protein predisposes the Z alpha(1)-antitrypsin homozygote to emphysema. Loop-sheet polymerization is now recognized to underlie deficiency variants of other members of the serine proteinase inhibitor (serpin) superfamily, i.e. antithrombin, C1 esterase inhibitor and alpha(1)-antichymotrypsin, which are associated with thrombosis, angio-oedema and emphysema respectively. Moreover, we have shown recently that the same process in a neuron-specific protein, neuroserpin, underlies a novel inclusion-body dementia, known as familial encephalopathy with neuroserpin inclusion bodies. Our understanding of the structural basis of polymerization has allowed the development of strategies to prevent the aberrant protein-protein interaction in vitro. This must now be achieved in vivo if we are to treat the associated clinical syndromes.

Tau proteins with frontotemporal dementia-17 mutations have both altered expression levels and phosphorylation profiles in differentiated neuroblastoma cells

The inherited form of frontotemporal dementia with Parkinsonism linked to chromosome 17 (FTDP-17) has been attributed to mutations in the tau gene. Pathologically, affected FTDP-17 brains share tau aggregates with other tauopathies, the most common being Alzheimer's disease. FTDP-17 mutations may therefore affect tau function leading to tau aggregation and cell loss. Interaction of tau with microtubules is thought to be regulated by phosphorylation. Investigating FTDP-17 mutations transiently expressed as enhanced green fluorescent protein (EGFP)-tagged proteins for the first time in differentiated neuronal cells, we found that two out of three missense mutations showed surprisingly decreased phosphorylation at the pathologically relevant S202/T205 site, mutant EGFP-tau being completely dephosphorylated in most cells. Moreover, phosphorylation at the S396/S404 site was moderately decreased for all mutant isoforms. Although microtubule integrity was not affected, with all mutants tested we demonstrated an increase in cellular tau protein level, some of which is microtubule-bound. Further enhancing this EGFP-tau accumulation by inhibition of tau degradation resulted in the previously less phosphorylated mutant EGFP-tau becoming highly phosphorylated. We conclude that the missense tau mutations primarily result in an excess of neuronal tau, which may interfere with important cellular functions such as axonal transport.

Familial Danish dementia: a novel form of cerebral amyloidosis associated with deposition of both amyloid-Dan and amyloid-beta

Familial Danish dementia (FDD) is pathologically characterized by widespread cerebral amyloid angiopathy (CAA), parenchymal protein deposits, and neurofibrillary degeneration. FDD is associated with a mutation of the BRI2 gene located on chromosome 13. In FDD there is a decamer duplication, which abolishes the normal stop codon, resulting in an extended precursor protein and the release of an amyloidogenic fragment, ADan. The aim of this study was to describe the major neuropathological changes in FDD and to assess the distribution of ADan lesions, neurofibrillary pathology, glial, and microglial response using conventional techniques, immunohistochemistry, confocal microscopy, and immunoelectron microscopy. We showed that ADan is widely distributed in the central nervous system (CNS) in the leptomeninges, blood vessels, and parenchyma. A predominance of parenchymal pre-amyloid (non-fibrillary) lesions was found. Abeta was also present in a proportion of both vascular and parenchymal lesions. There was severe neurofibrillary pathology, and tau immunoblotting revealed a triplet electrophoretic migration pattern comparable with PHF-tau. FDD is a novel form of CNS amyloidosis with extensive neurofibrillary degeneration occurring with parenchymal, predominantly pre-amyloid rather than amyloid, deposition. These findings support the notion that parenchymal amyloid fibril formation is not a prerequisite for the development of neurofibrillary tangles. The significance of concurrent ADan and Abeta deposition in FDD is under further investigation.

A presenilin 1 mutation associated with familial frontotemporal dementia inhibits gamma-secretase cleavage of APP and notch

A novel presenilin 1 mutation, insR352, associated with a frontal temporal dementia phenotype has been identified (E. A. Rogaeva et al., 2001, Neurology 57, 621-625). This mutation does not increase Abeta42 levels, but instead acts as dominant negative presenilin, decreasing amyloid beta protein (Abeta) production by inhibiting gamma-secretase cleavage of the Abeta precursor. The distinct clinical phenotype associated with this mutation suggests that chronic partial inhibition of gamma-secretase activity may result in neurodegeneration.

[Argyrophilic grain disease (AgD), a frequent and largely underestimated cause of dementia in old patients]

Argyrophilic grain disease (AgD) is a late-onset dementia morphologically characterized by abundant neuropil grains (ArGs). ArGs are mainly found in the CA1 subfield of the cornu ammonis, entorhinal and transentorhinal cortices, the amygdala and the hypothalamic lateral tuberal nuclei. We have recently shown that abnormally phosphosphorylated tau protein is the main protein constituent of ArGs and that tau is hyperphosphorylated in up to 80p.100 of nerve cels in areas rich in ArGs. We could demonstrate that at least a subset of grains are formed within dendrites and dendritic side-branches of neurons containing hyperphosphylated tau. Morphology of dendrites containing grains suggests that a process of progressive dendritic shrinkage is taking place in neurons bearing ArGs. Furthermore it became apparent that the presence of ArGs is not necessarily associated with a cognitive decline. Our studies on AgD cases with and without dementia suggest that AgD is a progressive neurodegenerative disorder with early subclinical lesions in anterior part of the hippocampal formation. At later stages involvement of more caudal parts of the hippocampal formation generally results in a cognitive decline. Thus, one possible explanation for the dementia observed in some subjects with AgD is that there is a more widepread loss of postsynaptic structures, including synaptic contacts, throughout the hippocampus-entorhinal/parahippocampal complex and the amygdaloid nuclei. Most of the reported AgD cases are associated with neurofibrillary lesions (e.g. neurofibrillary tangles) which are also typical of Alzheimer's disease (AD). However, neurofibrillary changes do not exceed early (entorhinal and limbic) Braak stages which generally are not associated with a cognitive decline. Additional neuropathological features of AgD include oligodendroglial tau filamentous inclusions ( coiled bodies ), ballooned neurons and astrocytic tau pathology. The clinical features of AgD are poorly understood. However, preliminary data from retrospective studies suggest that in AgD behavioural disturbances will precede memory failure and memory decline. Furthermore, it has been shown that the ApoEe4 allele does not constitute a risk factor for the development of AgD. In conclusion it seems very likely that AgD is a distinct dementing disorder of old age that has to be distinguished from other tauopathies, e.g. AD, by both morphological and genetic criteria.