Since Down syndrome (DS) is associated with amyloid β (Aβ) deposition, we characterized imaging measurements of regional fibrillar Aβ burden, cerebral metabolic rate (rCMRgl), gray matter volumes (rGMVs), and age associations in 5 DS with dementia (DS/AD+), 12 DS without dementia (DS/AD-), and 9 normal controls (NCs).There were significant group differences in mean SUVRs for florbetapir with DS/AD+ having the highest, followed by DS/AD-, followed by NC. For FDG-PET, posterior cingulate rCMRgl in DS/AD+ was significantly reduced compared to DS/AD- and NC. For vMRI, hippocampal volumes were significantly reduced for the DS/AD+ compared to DS/AD- and NC. Age-related SUVR increases and rCMRgl reductions were greater in DS participants than in NCs. DS is associated with fibrillar Aβ, rCMRgl, and l rGMV alterations in the dementia stage and prior to the presence of clinical decline. This study provides a foundation for the studies needed to inform treatment and prevention in DS.
Limited information regarding the specificity of mild cognitive impairment (MCI) as it relates to dementia with Lewy bodies (DLB) exists. Here, we summarize the clinical phenotype of MCI in clinically suspect DLB. Ten patients with a primary diagnosis of MCI and secondary diagnoses of DLB were identified. Patients underwent clinical neurological and neuropsychological evaluation that included application of McKeith criteria. We found parkinsonism and gait abnormality in 9 of the 10 patients; fluctuations in 8 of the 10; and hallucinations and dream enactment behavior in 5 of the 10. Of the 10 cases, 4 were classified as nonamnestic MCI and 6 were amnestic MCI. Of the 10 cases, 9 displayed executive and/or visuospatial dysfunction. Of the 10 cases, 6 have progressed to DLB. Progression of MCI to DLB is not dependent on memory impairment. The presence of core clinical features—parkinsonism and cognitive fluctuations—and predominant executive and visuospatial dysfunction ± memory impairment is suggestive of a prodromal DLB presentation.
mild cognitive impairment; dementia with Lewy bodies; unique clinical features; neuropsychological–cognitive profiles
In the present study, cerebrospinal fluid (CSF) profiles were assessed to determine how idiopathic normal pressure hydrocephalus (NPH) and Alzheimer’s disease (AD) differs.
Subjects were drawn from patients who underwent lumbar punctures as part of their diagnostic evaluations in the Banner Sun Health Research Institute Memory Disorders clinic. The clinical sample included 11 iNPH subjects (mean age 81.36±2.58) and 11 AD subjects (mean age 61.46±8.24). Concentrations of amyloid-β (Aβ42), total-tau (t-tau), phospho-tau181 (p-tau) Aβ42, and an Aβ42-Tau Index (ATI) were measured by commercial assay (Athena Diagnostics). and compared to each other. The Mann-Whitney test was used to assess group differences on the raw values for Aβ42, t-tau, p-tau, ATI, age, education, and MMSE.
In a univariate analysis, p-tau was found to be significantly (P = 0.009) lower in patients diagnosed with iNPH than those with AD. Amyloid-β (Aβ42), total-tau (t-tau) did not differ between groups. In multi-variate analysis, the differences in p-tau between groups did not differ.
Although age could represent a significant confound, p-tau is significantly lower in iNPH compared to AD. P-tau would be expected to increase with age but in this sample is lower suggesting the difference might be explained by the underlying condition.
Cerebrospinal fluid; Alzheimer disease; Normal pressure hydrocephalus; Amyloid; Tau proteins; Diagnosis
Hippocampal sclerosis (HS) is a neuropathological finding that frequently occurs with pathologies, such as Alzheimer's disease (AD). Prevalence estimates of HS in autopsy-confirmed dementia samples have varied between 0.4% and 24.5%. However, the prevalence of HS within other pathologic groups has not been well characterized.
Utilizing a sample of 910 prospectively followed and clinicopathologically confirmed dementia cases, we determined the prevalence of HS among the sample and within specific pathologic groups. HS prevalence of the sample was compared to reported HS prevalence rates in other autopsy-confirmed dementia samples.
The age range of the sample was 43 to 106 years, with a mean of 81.49±8.45. Of the 910 cases, 505 were male and 405 were female. For the entire sample, the average educational level was 14.59±2.65years. Of the 910 individuals, 47 (5.16%) cases had HS pathology present at autopsy. Among the 561 AD cases, 26 (4.43%) had HS pathology present. The frontotemporal dementia (FTD)/Pick's group had the highest percentage of cases with HS pathology (23.08%) followed by primary progressive aphasia (PPA) (16.67%) and Parkinson's disease with dementia (PDD) (5.34%). The HS prevalence rate of this study was not significantly different from all but 2 studies.
The prevalence of HS pathology in this sample of autopsy-confirmed dementia cases was similar to other reported HS prevalence rates. This study is the first to report the presence of HS pathology in PDD cases.
hippocampal sclerosis; dementia; neuropathology; TDP-43; Alzheimer's disease; Parkinson's disease
Down syndrome is one of the most common genetic conditions occurring in one in 700 live births. The trisomy of chromosome 21 causes over-expression of APP which in turn is indicated in the increased production of Aβ associated with AD. This makes DS the most common presenile form of AD exceeding PS1 and PS2 FAD. Since a majority of DS individuals develop dementia, it is important to examine whether DS and sporadic AD share common features, for example, to anticipate shared treatments in the future. Here we explore commonalities and differences for secretases and endosomal pathways in DS and AD.
Down syndrome; Trisomy; Over-expression
The objective is to examine the risk of dementia in subjects with essential tremor (ET) involved in the Arizona Study of Aging and Neurodegenerative Disorders. All subjects were free of a neurodegenerative diagnosis at baseline and had annual motor, general neurological, and neuropsychological assessments. Subjects with ET were compared with controls for the risk of dementia. There were 83 subjects with ET and 424 subjects without tremor. Mean age at study entry was 80 ± 5.9 for ET and 76 ± 8.5 for controls. Median tremor duration was 5.2 years at study entry. Followup was a median of 5.4 years (range 0.9 to 12.1). The hazard ratio for the association between ET and dementia was 0.79 (95% CI 0.33 to 1.85). The hazard ratio for the association between tremor onset at age 65 or over, versus onset before age 65, was 2.1 (95% CI 0.24 to 18) and the hazard ratio for the association between tremor duration greater than 5 years, versus less than 5 years, was 0.46 (95% CI 0.08 to 2.6). We conclude that all elderly ET was not associated with an increased risk of dementia but that a subset of subjects with older age onset/shorter duration tremor may be at higher risk.
Down syndrome appears to be associated with a virtually certain risk of fibrillar amyloid-β (Aβ) pathology by the age of 40 and a very high risk of dementia at older ages. The positron emission tomography (PET) ligand florbetapir F18 has been shown to characterize fibrillar Aβ in the living human brain and to provide a close correlation with subsequent Aβ neuropathology in individuals proximate to and after the end of life. The extent to which the most frequently used PET ligands can be used to detect fibrillar Aβ in patients with Down syndrome remains to be determined.
To characterize PET estimates of fibrillar Aβ burden in a Down syndrome patient very close to the end of life and to compare them with neuropathologic assessment made after his death.
With the family’s informed consent, florbetapir PET was used to study a 55-year-old Down syndrome patient with Alzheimer disease near the end of life; his brain was donated for neuropathologic assessment when he died 14 days later. Visual ratings of cerebral florbetapir uptake were performed by trained readers who were masked to the patient’s diagnosis as part of a larger study, and an automated algorithm was used to characterize regional-to-cerebellar standard uptake value ratios in 6 cerebral regions of interest. Neuropathologic assessments were performed masked to the patient’s diagnosis or PET measurements.
Visual ratings and automated analyses of the PET image revealed a heavy fibrillar Aβ burden in cortical, striatal, and thalamic regions, similar to that reported for patients with late-onset Alzheimer disease. This matched neuropathologic findings of frequent neuritic and diffuse plaques, as well as frequent amyloid angiopathy, except for neuropathologically demonstrated frequent cerebellar diffuse plaques and amyloid angiopathy that were not detected by the PET scan.
Florbetapir PET can be used to detect increased cerebral-to-cerebellar fibrillar Aβ burden in a Down syndrome patient with Alzheimer disease, even in the presence of frequent amyloid angiopathy and diffuse plaques in the cerebellum. Additional studies are needed to determine the extent to which PET could be used to detect and to track fibrillar Aβ and to evaluate investigational Aβ-modifying treatments in the presymptomatic and symptomatic stages of Alzheimer disease.
Normal pressure hydrocephalus (NPH) is considered potentially treatable with the placement of a cerebrospinal fluid (CSF) shunt. Yet, the procedure has had variable success, particularly with respect to improving the cognitive impairment in NPH. The presence of neurologic co-morbidities, particularly Alzheimer's Disease (AD), may contribute to shunt responsiveness. Uncovering the extent to which AD and NPH co-occur has implications for diagnosis and treatment of NPH. Autopsy studies of patients with NPH during life would elucidate the frequency of such co-morbidities.
We conducted a search of the Sun Health Research Institute Brain Donation Program database between 1/1/1997 and 4/1/09 to identify all cases with neuropathologic evidence of dementia as well as those cases of clinically diagnosed NPH. We reviewed the medical records and brain findings of each NPH case.
Of the 761 cases autopsied over the study interval, 563 cases were found to have neuropathological evidence meeting criteria for a dementing illness. AD was found exclusively in 313/563 (56%) cases with 94/563 cases having a secondary diagnosis of dementia.
We identified 9/761 cases with a clinical diagnosis of NPH, all nine cases were among the 563 cases with neuropathology of dementing illness at autopsy, representing 1.6% (9/563). Upon review of brain autopsy reports, 8/9 (89%) cases were found to have AD and 1/9 (11%) had progressive supranuclear palsy. Review of the medical records of the nine NPH cases revealed the following clinical co-morbidities: 5/9 with AD; 1/9 with Parkinson's Disease (PD); 1/9 with Mild Cognitive Impairment (MCI); 1/9 with seizure disorder.
Given the findings of our study, we support the AD-NPH theory and posit that AD is a common pathological co-morbidity in the setting of NPH and may preclude cognitive improvement post-shunt placement. This may have influence on selection of cases for shunting in the future.
normal pressure hydrocephalus; Alzheimer's disease; cerebrospinal fluid shunt; autopsy study; dementia
A substantial body of evidence amassed from epidemiologic, correlative and experimental studies strongly associates atherosclerotic vascular disease (AVD) with Alzheimer's disease (AD). Depending on the precise interrelationship between AVD and AD, systematic application of interventions to maintain vascular health and function as a component of standard AD therapy offers the prospect of mitigating what is presently the inexorable course of dementia. To assess this hypothesis it is vital to rigorously establish the measures of AVD that are most strongly associated with an AD diagnosis.
A precise neuropathological diagnosis was established for all subjects using a battery of genetic, clinical, and histological methods. The severity of atherosclerosis in the circle of Willis (CW) was quantified by direct digitized measurement of arterial occlusion in postmortem specimens and compared between AD and non-demented control (NDC) groups by calculating a corresponding index of occlusion.
Atherosclerotic occlusion of the CW arteries was more extensive in the AD group than the NDC group. Statistically significant differences were also observed between control and AD groups with regard to Braak stage, total plaque score, total NFT score, total white matter rarefaction score, brain weight, MMSE scores and apolipoprotein E allelic frequencies.
Our results, combined with a consideration of the multifaceted impacts of impaired cerebral circulation, suggest an immediate need for prospective clinical trials to assess the efficacy of AD prevention using anti-atherosclerotic agents.
Alzheimer's disease; vascular dementia; intracranial atherosclerosis; circle of Willis; brain hypoperfusion
The ability to understand how Parkinson’s disease (PD) neurodegeneration leads to cortical dysfunction will be critical for developing therapeutic advances in PD dementia (PD-D). The overall purpose of this project was to study the small amplitude cortical myoclonus in PD as an in vivo model of focal cortical dysfunction secondary to PD neurodegeneration. The objectives were to test the hypothesis that cortical myoclonus in PD is linked to abnormal levels of α-synuclein in primary motor cortex and to define its relationship to various biochemical, clinical, and pathological measures.
Primary motor cortex was evaluated for 11 PD subjects with (PD+Myoclonus group) and 8 without (PD group) electrophysiologically confirmed cortical myoclonus who had premortem movement and cognitive testing. Similarly assessed 9 controls were used for comparison. Measurements for α-synuclein, Aβ-42 peptide, and other biochemical measures were made in primary motor cortex.
A 36% increase in α-synuclein was found in the motor cortex of PD+Myoclonus cases when compared to PD without myoclonus. This occurred without significant differences in insoluble α-synuclein, phosphorylated to total α-synuclein ratio, or Aβ-42 peptide levels. Higher total motor cortex α-synuclein levels significantly correlated with the presence of cortical myoclonus but did not correlate with multiple clinical or pathological findings.
These results suggest an association between elevated α-synuclein and the dysfunctional physiology arising from the motor cortex in PD+Myoclonus cases. Alzheimer’s disease pathology was not associated with cortical myoclonus in PD. Cortical myoclonus arising from motor cortex is a model to study cortical dysfunction in PD.
To evaluate the safety and tolerability of PF-04494700, an oral Inhibitor of receptor for advanced glycation end products (RAGE), in subjects with mild-to-moderate dementia of the Alzheimer’s type.
Subjects 50 years and older who met NINCDS-ADRDA criteria for AD with an MMSE score between 12–26 (inclusive) were randomized to 10-weeks of double-blind treatment with either a 10 mg “low dose” of PF-04494700 (after a 6-day loading dose of 30 mg/d to); or a 20 mg “high dose” of PF-04494700 (after a loading dose of 60 mg/d); or placebo. Safety measures included adverse events, laboratory tests, vital signs, and 12-lead ECG.
27 subjects received PF-04494700 30/10 mg (female, 63%; mean age, 74.6 years; mean MMSE, 21.1), 28 subjects received PF-04494700 60/20 mg (female, 57%; mean age, 76.6 years; mean MMSE, 21.6), and 12 subjects received placebo (female, 67%; mean age, 74.1 years; mean MMSE, 19.2). A higher proportion of subjects completed 10 weeks of double-blind treatment on both the “low dose” regimen of PF-04494700 (88.9%) and the “high dose” regimen (85.7%) than completed on placebo (66.7%). Discontinuation due to adverse events, and incidence of severe adverse events, respectively, were lower on the “low dose” regimen (7.4%,11.1%) and the “high dose” regimen (3.6%,10.7%) compared to placebo (25.0%,16.7%). There were no clinically meaningful differences in vital signs, laboratory test results, or mean ECG parameters in subjects treated with PF-04494700. PF-04494700 had no consistent effect on plasma levels of Aβ, inflammatory biomarkers, or secondary cognitive outcomes.
Ten weeks of treatment with PF-04494700 was safe and well-tolerated in subjects with mild-to-moderate AD, indicating the feasibility of a larger long-term efficacy trial.
Alzheimer’s disease; randomized clinical trial; RAGE
To describe a case of early-onset Alzheimer's disease (AD) in an apolipoprotein (Apo) ∊2/∊2 homozygote.
Apo ∊2/∊2 is the rarest of the ApoE genotypes, representing only 1.4% of the population. Cognitive decline in ApoE ∊2 homozygotes has rarely been reported. Case Report/Methods: We report a 58-year-old Apo ∊2/∊2 female who meets clinical criteria for probable AD as confirmed by neuropsychological testing, positron emission/computed tomography scan, CSF analysis and genetic screening for known mutations.
The clinical course is typical of AD, with progressive cognitive and functional decline.
Clinically confirmed early-onset AD is atypical in ApoE2 homozygotes but can occur.
Alzheimer's disease; Apolipoprotein E2; Homozygote; Positron emission tomography scan; Neuropsychological assessment; Cerebrospinal fluid analysis
The aim of this pilot study is to determine the feasibility and clinical utility of a brief, informant-based screening questionnaire for Alzheimer’s disease (AD) that can be administered in a primary care setting. The Alzheimer’s Questionnaire (AQ) was administered to the informants of 188 patients in 3 dementia clinics (50 cognitively normal, 69 mild cognitive impairment (MCI), 69 AD). Total score for the AQ is based upon the sum of clinical symptom items in which the informant responds as being present. Clinical symptoms which are known to be highly predictive of the clinical AD diagnosis are given greater weight in the total AQ score. The mean time of administration of the AQ was 2.6 ± 0.6 minutes. Sensitivity and specificity were found to be high for detecting both AD (98.55, 96.00) and MCI (86.96, 94.00) with ROC curves yielding AUC values of 0.99 and 0.95, respectively. This pilot study indicates that the AQ is a brief, sensitive measure for detecting both MCI and AD and could be easily implemented in a primary care setting.
Alzheimer’s disease; instrument; questionnaire; primary care
The objective of this study was to describe a case of Alzheimer’s disease in an ApoE ε2/ε2 homozygote. ApoE ε2/ε2 is the rarest of the apolipoprotein E genotypes, representing only 1.4% of the population. There is only one case reported in the literature of a nonagenarian with minimal cognitive changes whose brain showed AD pathology on postmortem study. Here we report an 87-year-old ApoE ε2/ε2 female who meets clinical criteria for Alzheimer’s disease, with confirmation from neuropsychological testing and PET scan. Clinical course is typical for Alzheimer’s disease with decline on the Mini-Mental Status Examination from a score of 25 to 19 over 3.5 years. The patient is currently treated with donepezil and memantine. In conclusion, a clinically confirmed case of Alzheimer’s disease is rare in Apo E2 homozygotes but can occur.
Alzheimer’s disease; apolipoprotein E2; homozygote; PET scan
Subjects with Parkinson's disease (PD) frequently develop dementia with greater than one-third meeting neuropathologic diagnostic criteria for Alzheimer's disease (AD). The objective is to identify clinical and neuropathological differences between PDD (PD with dementia) subjects, with and without coexistent AD pathology. Neuropathologic examination was available on subjects diagnosed by clinicopathologic criteria with PDD-AD (N = 23) and PDD+AD (N = 28). A small subset of subjects with PDD-AD and PDD+AD had received at least one standardized neuropsychological assessment. PDD+AD subjects were significantly older at age of PD onset and death, progressed to onset of dementia in less time, and had a shorter duration of PD symptoms prior to the onset of dementia. Education, responsiveness of L-Dopa and dopaminergic medications, presence of cognitive fluctuations and hallucinations, mean MMSE, GDS, FAST and UPDRS scores did not differ significantly between the two groups. The PDD+AD group had significantly greater total plaques, neuritic plaques, total tangles, and Braak stages compared to PDD-AD. This study suggests that it is difficult to distinguish PDD+AD and PDD-AD on the basis of movement, clinical, and neuropsychological assessment. PDD-AD and PDD+AD have similar degrees of dementia and approximately half of PDD subjects have enough AD pathology to attain a neuropathological diagnosis of AD. PDD can develop in the absence of significant Alzheimer pathology.
Parkinson' disease with dementia; Alzheimer's Disease; Dementia with Lewy Bodies; assessment of dementia
Argyrophilic grains (AGs) are a pathologic feature found in association with neurodegenerative disease. Some have suggested that these features may occur as a distinctive condition. We reviewed 80 subjects from our tissue bank with pathologically confirmed AGs and identified their clinical features. We compared these subjects' features to the features of subjects with matched clinical diagnoses but without AGs. Subjects with AGs represented 21.7% of the entire autopsy sample from 1999 through 2005 (80/367). Of AD subjects, 43 /233 had AGs (18.4% of AD subjects); 11 /42 PD-D subjects had AGs (26.1% of PDD subjects); 2 / 9 DLB subjects had AGs (22.2% of DLB subjects); 4 /15 MCI subjects had AGs (26.7% of MCI subjects); and 20 /68 cognitively normal subjects had AGs (29.4% of NC). Subjects with AGs tended to be older but only significantly so in AD. Many co-morbid non-neurological health conditions were seen in cases of AGs without any single predilection emerging. AGs occur in approximately 22% of the entire autopsy cohort and likely are associated with advanced age. No distinctive antemortem clinical features were overrepresented in the AG cases. AGs can occur with or without neurodegenerative conditions and can occur in the absence of significant cognitive decline. AGs are not clearly associated with any single co-morbid health condition.
Argyrophilic grains; dementia; neurodegeneration; neuropathology
Olfactory dysfunction in Parkinson's disease (PD) is well-established and may represent one of the earliest signs of the disease.
Objective & methods
The objective of this study was to evaluate the relationship of olfactory dysfunction, using the University of Pennsylvania Smell Identification Test (UPSIT), to clinical and pathological parameters of clinicopathologically diagnosed PD (n = 10), incidental Lewy body disease (ILBD) (n = 13), and identically assessed controls who lacked a neurodegenerative disease (n = 69).
Mean UPSIT scores were significantly lower in PD (16.3, p < 0.001) and ILBD (22.2, p = 0.004) compared to controls (27.7). Using an UPSIT cutoff score of <22 (the 15th percentile) the sensitivity for detecting PD was 9/10 (90%) and ILBD 6/13 (46%), while the specificity was 86% (Controls with score of <22 = 10/69).
= These results add to the growing body of evidence suggesting that olfactory testing could be useful as a screening tool for identifying early, pre-motor PD.
Parkinson's disease; Hyposmia; Incidental Lewy body disease
To determine what differences exist in graph theory network measures derived from electroencephalography (EEG), between Parkinson's disease (PD) patients who are cognitively normal (PD-CN) and matched healthy controls; and between PD-CN and PD dementia (PD-D).
EEG recordings were analyzed via graph theory network analysis to quantify changes in global efficiency and local integration. This included minimal spanning tree analysis. T-tests and correlations were used to assess differences between groups and assess the relationship with cognitive performance.
Network measures showed increased local integration across all frequency bands between Control and PD-CN; in contrast, decreased local integration occurred in PD-D when compared to PD-CN in the alpha1 frequency band. Differences found in PD-MCI mirrored PD-D. Correlations were found between network measures and assessments of global cognitive performance in PD.
Our results reveal distinct patterns of band and network measure type alteration and breakdown for PD, as well as with cognitive decline in PD.
These patterns suggest specific ways that interaction between cortical areas becomes abnormal and contributes to PD symptoms at various stages. Graph theory analysis by EEG suggests that network alteration and breakdown are robust attributes of PD cortical dysfunction pathophysiology.
Parkinson's disease; dementia; biomarker; EEG; network, synucleinopathy; pathology
To identify a panel of peripheral inflammatory/immune mediators that could discriminate Parkinson disease with dementia (PDD) from Parkinson disease (PD) without dementia.
Plasma samples from 52 patients with PD and 22 patients with PDD were prepared from freshly collected blood following an institutional review board–approved protocol. A total of 160 proteins were measured using a multiplex antibody array. Plasma α-synuclein levels were analyzed by an electrochemiluminescence immunoassay. The main objective of the statistical analyses was to identify PDD discriminants using the plasma protein profile alone or in combination with age.
The PD and PDD groups differed significantly in cognitive measurements (Mini-Mental State Examination, Auditory Verbal Learning Test-A7, and Clinical Dementia Rating) and age. The age-adjusted levels of thymus and activation-regulated chemokine (TARC) and platelet-derived growth factor (PDGF)-AA were significantly different between disease groups. The levels of plasma α-synuclein significantly correlated with 26 proteins; among them, PDGF-BB, TARC, PDGF-AA, and epidermal growth factor were the highest. Linear discriminant analysis with leave-one-out cross-validation identified a 14-protein panel with age as discriminants of PDD (96% sensitivity, 89% specificity, area under the curve = 0.9615).
We showed that multiple proteins that are mediators of growth/trophic and immune response-related pathways had discriminatory power for identifying PDD in patients with PD. Validation of this discovery-based study in longitudinal population-based studies is warranted.
Classification of evidence:
This study provides Class III evidence that a 14-protein panel plasma assay combined with age has a sensitivity of 96% and a specificity of 89% for PDD.
The Brain and Body Donation Program (BBDP) at Banner Sun Health Research Institute (http://www.brainandbodydonationprogram.org) started in 1987 with brain-only donations and currently has banked more than 1600 brains. More than 430 whole-body donations have been received since this service was commenced in 2005. The collective academic output of the BBDP is now described as the Arizona Study of Aging and Neurodegenerative Disorders (AZSAND). Most BBDP subjects are enrolled as cognitively normal volunteers residing in the retirement communities of metropolitan Phoenix, Arizona. Specific recruitment efforts are also directed at subjects with Alzheimer’s disease, Parkinson’s disease and cancer. The median age at death is 82. Subjects receive standardized general medical, neurological, neuropsychological and movement disorders assessments during life and more than 90% receive full pathological examinations by medically licensed pathologists after death. The Program has been funded through a combination of internal, federal and state of Arizona grants as well as user fees and pharmaceutical industry collaborations. Subsets of the Program are utilized by the US National Institute on Aging Arizona Alzheimer’s Disease Core Center and the US National Institute of Neurological Disorders and Stroke National Brain and Tissue Resource for Parkinson’s Disease and Related Disorders. Substantial funding has also been received from the Michael J. Fox Foundation for Parkinson’s Research. The Program has made rapid autopsy a priority, with a 3.0-hour median postmortem interval for the entire collection. The median RNA Integrity Number (RIN) for frozen brain and body tissue is 8.9 and 7.4, respectively. More than 2500 tissue requests have been served and currently about 200 are served annually. These requests have been made by more than 400 investigators located in 32 US states and 15 countries. Tissue from the BBDP has contributed to more than 350 publications and more than 200 grant-funded projects.
aging; Alzheimer’s disease; autopsy; biobank; biospecimen; brain bank; cancer; freeze-thaw; Parkinson’s disease; pathology; post-mortem interval; RNA
Visual symptoms are relatively common in Parkinson’s disease (PD) and optical coherence tomography has indicated possible retinal thinning. Accumulation of aggregated α-synuclein is thought to be a central pathogenic event in the PD brain but there have not as yet been reports of retinal synucleinopathy. Retinal wholemounts were prepared from subjects with a primary clinicopathological diagnosis of PD (N = 9), dementia with Lewy bodies (DLB; N = 3), Alzheimer’s disease (N = 3), progressive supranuclear palsy (N = 2) as well as elderly normal control subjects (N = 4). These were immunohistochemically stained with an antibody against α-synuclein phosphorylated at serine 129, which is a specific molecular marker of synucleinopathy. Phosphorylated α-synuclein-immunoreactive (p-syn IR) nerve fibers were present in 7/9 PD subjects and in 1/3 DLB subjects; these were sparsely distributed and superficially located near or at the inner retinal surface. The fibers were either long and straight or branching, often with multiple en-passant varicosities along their length. The straight fibers most often had an orientation that was radial with respect to the optic disk. Together, these features are suggestive of either retinopetal/centrifugal fibers or of ganglion cell axons. In one PD subject there were sparse p-syn IR neuronal cell bodies with dendritic morphology suggestive of G19 retinal ganglion cells or intrinsically photosensitive ganglion cells. There were no stained nerve fibers or other specific staining in any of the non-PD or non-DLB subjects. It is possible that at least some of the observed visual function impairments in PD subjects might be due to α-synucleinopathy.
Lewy body; Pathology; Autopsy; Diagnosis; Melanopsin; Ganglion cell
Mild cognitive impairment (MCI) represents a cognitive state intermediate between normal aging and early Alzheimer Disease (AD). To investigate if the molecular signature of MCI parallels the clinical picture, we use microarrays to extensively profile gene expression in 4 cortical brain regions (entorhinal cortex, hippocampus, superior frontal gyrus, post-central gyrus) using post-mortem tissue from cognitively normal aged controls, MCI, and AD cases. Our data reveal that gene expression patterns in MCI are not an extension of aging, and for the most part, are not intermediate between aged controls and AD. Functional enrichment analysis of significant genes revealed prominent upregulation in MCI brains of genes associated with anabolic and biosynthetic pathways (notably transcription, protein biosynthesis, protein trafficking and turnover) as well as mitochondrial energy generation. In addition, many synaptic genes showed altered expression in MCI, predominantly upregulation, including genes for central components of the vesicle fusion machinery at the synapse, synaptic vesicle trafficking, neurotransmitter receptors, and synaptic structure and stabilization. These data suggest that there is a rebalancing of synaptic transmission in the MCI brain. To investigate if synaptic gene expression levels in MCI were related to cognitive function, Pearson’s correlation coefficient between MMSE and region-specific mRNA expression were computed for MCI cases. A number of synaptic genes showed strong significant correlations (r>0.8, p<0.01) most notably in the EC, with fewer in the HC, and very few in neocortical regions. The synaptic genes with highly significant correlations were predominantly related to synaptic transmission and plasticity, and myelin composition. Unexpectedly, we found that gene expression changes that facilitate synaptic excitability and plasticity were overwhelmingly associated with poorer MMSE, and conversely that gene expression changes that inhibit plasticity were positively associated with MMSE. These data suggest that there is excessive excitability and apparent plasticity in limbic brain regions in MCI, that is associated with impaired synaptic and cognitive function. Such changes would be predicted to contribute to increased excitability, in turn leading to greater metabolic demand and ultimately progressive degeneration and AD, if not controlled.
Microarray; Synapse; Electron transport; Mitochondria; SNARE; Neurotransmitter receptor; Hippocampus; Entorhinal cortex; Superior frontal gyrus; Somatosensory cortex
Previous research has linked complex or formed visual hallucinations (VH) to Lewy-type alpha-synucleinopathy (LTS) in neocortical and limbic areas. As Alzheimer’s disease pathology often co-occurs with LTS, we questioned whether this pathology - amyloid plaques and neurofibrillary tangles - might also be linked to VH.
We performed a semi-quantitative neuropathological study across brainstem, limbic, and cortical structures in subjects with a documented clinical history of VH and a clinicopathological diagnosis of Parkinson’s disease (PD), Alzheimer’s disease (AD), or dementia with Lewy bodies (DLB). 173 subjects – including 50 with VH and 123 without VH – were selected from the Arizona Study of Aging and Neurodegenerative Disorders. Clinical variables examined included the Mini-mental State Exam, Hoehn & Yahr stage, and total dopaminergic medication dose. Neuropathological variables examined included total and regional LTS and plaque and tangle densities.
A significant relationship was found between the density of LTS and the presence of VH in PD, AD, and DLB. Plaque and tangle densities also were associated with VH in PD (p=.003 for plaque and p=.004 for tangles) but not in AD, where densities were high regardless of the presence of hallucinations. Furthermore, with DLB cases excluded, comorbidity of PD and AD was significantly more prevalent among subjects +VH than subjects −VH (p<.001).
These findings suggest that both AD and PD neuropathology contribute to the pathogenesis of VH. Incident VH could be predictive of concomitant AD/PD pathology even when criteria are not met for a second diagnosis.
visual hallucinations; hallucinations; psychosis; Alzheimer’s disease; Parkinson’s disease