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Lewy- and Alzheimer-type pathologies in Parkinson's disease dementia: which is more important?

ABSTRACT: The relative importance of Lewy- and Alzheimer-type pathologies to dementia in Parkinson's disease remains unclear. We have examined the combined associations of ?-synuclein, tau and amyloid-? accumulation in 56 pathologically confirmed Parkinson's disease cases, 29 of whom had developed dementia. Cortical and subcortical amyloid-? scores were obtained, while tau and ?-synuclein pathologies were rated according to the respective Braak stages. Additionally, cortical Lewy body and Lewy neurite scores were determined and Lewy body densities were generated using morphometry. Non-parametric statistics, together with regression models, receiver-operating characteristic curves and survival analyses were applied. Cortical and striatal amyloid-? scores, Braak tau stages, cortical Lewy body, Lewy neurite scores and Lewy body densities, but not Braak ?-synuclein stages, were all significantly greater in the Parkinson's disease-dementia group (P<0.05), with all the pathologies showing a significant positive correlation to each other (P<0.05). A combination of pathologies [area under the receiver-operating characteristic curve=0.95 (0.88-1.00); P<0.0001] was a better predictor of dementia than the severity of any single pathology. Additionally, cortical amyloid-? scores (r=-0.62; P=0.043) and Braak tau stages (r=-0.52; P=0.028), but not Lewy body scores (r=-0.25; P=0.41) or Braak ?-synuclein stages (r=-0.44; P=0.13), significantly correlated with mini-mental state examination scores in the subset of cases with this information available within the last year of life (n=15). High cortical amyloid-? score (P=0.017) along with an older age at onset (P=0.001) were associated with a shorter time-to-dementia period. A combination of Lewy- and Alzheimer-type pathologies is a robust pathological correlate of dementia in Parkinson's disease, with quantitative and semi-quantitative assessment of Lewy pathology being more informative than Braak ?-synuclein stages. Cortical amyloid-? and age at disease onset seem to determine the rate to dementia.

SUBMITTER: Compta Y

PROVIDER: S-EPMC4194668 | biostudies-literature | 2011 May

REPOSITORIES: biostudies-literature

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Lewy- and Alzheimer-type pathologies in Parkinson's disease dementia: which is more important?

Compta Yaroslau Y Parkkinen Laura L O'Sullivan Sean S SS Vandrovcova Jana J Holton Janice L JL Collins Catherine C Lashley Tammaryn T Kallis Constantinos C Williams David R DR de Silva Rohan R Lees Andrew J AJ Revesz Tamas T

Brain : a journal of neurology 20110501 Pt 5

The relative importance of Lewy- and Alzheimer-type pathologies to dementia in Parkinson's disease remains unclear. We have examined the combined associations of α-synuclein, tau and amyloid-β accumulation in 56 pathologically confirmed Parkinson's disease cases, 29 of whom had developed dementia. Cortical and subcortical amyloid-β scores were obtained, while tau and α-synuclein pathologies were rated according to the respective Braak stages. Additionally, cortical Lewy body and Lewy neurite sco ...[more]

PMID: 21596773

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Project description:The clinical delineation of dementia with Lewy bodies (DLB) from Alzheimer disease (AD) remains unclear.To compare neuropsychological profiles in DLB and AD among Caribbean Hispanic family members and participants in a population-based epidemiologic sample using extended neuropsychological test batteries and to explore whether these differences were related to heritable factors.Cross-sectional study.Clinics in northern Manhattan (New York City), the Dominican Republic, and Puerto Rico.We compared measures of memory, orientation, language, and executive and visuospatial functioning between patients with DLB vs AD in 2 Caribbean Hispanic cohorts, including a family sample (89 patients with DLB and 118 patients with AD) and an epidemiologic sample (70 patients with DLB and 157 patients with AD). Patients with DLB in the family sample were further categorized as patients having at least 2 family members with DLB or as patients having 1 family member with DLB.To determine whether observed differences in cognitive profiles were driven by heritable factors, we repeated analyses in the epidemiologic sample after excluding familial cases. We applied general linear models adjusted for age, sex, educational level, disease duration, and apolipoprotein E epsilon4 (OMIM 104310) genotype.Patients with DLB in both samples were more severely impaired in orientation, visuoconstruction, and nonverbal reasoning after controlling for potential confounders. Patients having at least 2 family members with DLB had the most severe impairment in memory, followed by patients having 1 family member with DLB, and then by patients with AD. After excluding familial AD and DLB cases in the epidemiologic sample, the differences between the groups persisted but were attenuated.Compared with patients having AD, patients having DLB are more severely impaired in various cognitive domains, particularly orientation and visuospatial functioning. The difference seems stronger in familial DLB than in sporadic DLB. Whether this divergence in cognitive functions is caused by gene-gene or gene-environmental interactions remains unclear.

Project description:As the differential diagnosis of dementias based on established clinical criteria is often difficult, biomarkers for applicable diagnostic testing are currently under intensive investigation. Amyloid plaques deposited in the brain of patients suffering from Alzheimer's disease, dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD) mainly consist of carboxy-terminally elongated forms of amyloid-beta (Abeta) peptides, such as Abeta1-42. Absolute Abeta1-42 levels in CSF have shown diagnostic value for the diagnosis of Alzheimer's disease, but the discrimination among Alzheimer's disease, DLB and PDD was poor. A recently established quantitative urea-based Abeta-sodium-dodecylsulphate-polyacrylamide-gel-electrophoresis with Western immunoblot (Abeta-SDS-PAGE/immunoblot) revealed a highly conserved Abeta peptide pattern of the carboxy-terminally truncated Abeta peptides 1-37, 1-38, 1-39 in addition to 1-40 and 1-42 in human CSF. We used the Abeta-SDS-PAGE/immunoblot to investigate the CSF of 23 patients with Alzheimer's disease, 21 with DLB, 21 with PDD and 23 non-demented disease controls (NDC) for disease-specific alterations of the Abeta peptide patterns in its absolute and relative quantities. The diagnostic groups were matched for age and severity of dementia. The present study is the first attempt to evaluate the meaning of Abeta peptide patterns in CSF for differential diagnosis of the three neurodegenerative diseases--Alzheimer's disease, DLB and PDD. The Abeta peptide patterns displayed disease-specific variations and the ratio of the differentially altered Abeta1-42 to the Abeta1-37 levels subsequently discriminated all diagnostic groups from each other at a highly significant level, except DLB from PDD. Additionally, a novel peptide with Abeta-like immunoreactivity was observed constantly in the CSF of all 88 investigated patients. The pronounced percentage increase of this peptide in DLB allowed a highly significant discrimination from PDD. Using a cut-off point of 0.954%, this marker yielded a diagnostic sensitivity and specificity of 81 and 71%, respectively. From several lines of indication, we consider this peptide to represent an oxidized alpha-helical form of Abeta1-40 (Abeta1-40*). The increased abundance of Abeta1-40* probably reflects a disease-specific alteration of the Abeta1-40 metabolism in DLB. We conclude that Abeta peptide patterns reflect disease-specific pathophysiological pathways of different dementia syndromes as distinct neurochemical phenotypes. Although Abeta peptide patterns failed to fulfil the requirements for a sole biomarker, their combined evaluation with other biomarkers is promising in neurochemical dementia diagnosis. It is noteworthy that DLB and PDD exhibit distinct clinical temporal courses, despite their similar neuropathological appearance. Their distinct molecular phenotypes support the view of different pathophysiological pathways for each of these neurodegenerative diseases.

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Lewy- and Alzheimer-type pathologies in Parkinson's disease dementia: which is more important?

Publications

Lewy- and Alzheimer-type pathologies in Parkinson's disease dementia: which is more important?

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