Dementia with Lewy bodies

Glucose levels during life and neuropathologic findings at autopsy among people never treated for diabetes

We evaluated associations between glucose and dementia-related neuropathologic findings among people without diabetes treatment history to elucidate mechanisms of glucose's potential effect on dementia. We used glucose and hemoglobin A1c values to characterize glucose exposures over 5 years before death (primary) and age bands from 55-59 through 80-84 (secondary). Autopsy evaluations included Braak stage for neurofibrillary tangles, Consortium to Establish a Registry for Alzheimer's Disease grade for neuritic plaques, macroscopic infarcts including lacunar infarcts, Lewy bodies, cerebral microinfarcts, and hippocampal sclerosis. Of 529 who came to autopsy, we included 430 with no history of diabetes treatment. We found no associations between glucose levels and Braak stage or Consortium to Establish a Registry for Alzheimer's Disease grade. There was a suggestion of a relationship between glucose and hippocampal sclerosis, although this was inconsistent across analyses. There was higher risk of Lewy bodies in substantia nigra and locus ceruleus with higher glucose levels in age band analyses. We did not find interactions between glucose levels, neuropathologic findings, and dementia. The mechanism by which glucose may impact dementia risk is still unknown.

A typology of care-giving across neurodegenerative diseases presenting with dementia

The purpose of this study is to develop and extend our understanding of dementia care-giving by introducing a typology of informal care-giving across four different diseases. Care-giving factors were examined with respect to specific dementia presentation in mild cognitive impairment, Alzheimer's disease, dementia with Lewy bodies and Parkinson's disease-associated dementia. Informal care-giving literature in the four diseases was systematically searched to identify specific disease symptoms and resultant care-giving strains and outcomes. Key concepts were extracted and grouped thematically. The first classification, ‘role-shift’, reflects care-giving where cognitive deterioration results in changing roles, uncertainty and relational deprivation among married partners. The second classification, ‘consumed by care-giving’, refers to those caring for persons with dementia-motor decline that greatly increases worry and isolation. Finally, in the ‘service use’ classification, formal support is needed to help care-givers cope with daily responsibilities and behaviour changes. In each case, the dementia presentation uniquely impacts care-giver strains. A major conclusion is that the same support to all care-givers under the umbrella term ‘dementia’ is unwarranted; the development of targeted support is required.

Adult Changes in Thought study: dementia is an individually varying convergent syndrome with prevalent clinically silent diseases that may be modified by some commonly used therapeutics

The Adult Changes in Thought (ACT) study is a longitudinal population-based prospective cohort study of brain aging and incident dementia in the Seattle metropolitan area. Observational studies using autopsies from ACT indicate that dementia is a convergent syndrome that commonly derives from Alzheimer's disease (AD), microvascular brain injury (mVBI), and Lewy body disease (LBD), and that these diseases have prevalent subclinical forms that also are commonly co-morbid. The existence of subclinical diseases highlights potential opportunities to intervene before the development of clinically apparent impairments. Our observations suggest that some such interventions already may exist to suppress processes of AD (statin therapy) or mVBI (treatment of hypertension). Reduced burden of LBD is associated with cigarette smoking; although smoking is not recommended as an intervention, these exposure data may provide clues to alternative neuroprotective mechanisms. Self reported anti-oxidant supplementation was without apparent effect in this cohort on indices of AD, mVBI, or LBD. Continued observational studies of brain aging will provide further insight into the convergent complexity of the dementia syndrome and its subclinical forms as well as highlight potential interventions that will require validation in clinical trials.

Nonmotor symptoms in Parkinson’s disease: the dark side of the moon

Nonmotor symptoms may appear during the course of Parkinson’s disease, complicating the advanced phase in particular, but are also common in the premotor phase of Parkinson’s disease. The appearance of nonmotor manifestations represents a milestone, determining a worse prognosis and lower quality of life; however, they are often misdiagnosed and untreated. The spectrum of nonmotor symptoms encompasses mood disorders, psychosis, dementia, sleep disorders, impulse-control disorders and autonomic dysfunctions. This article describes these nonmotor symptoms and their management.

Neuropathology in the adult changes in thought study: a review

The neuropathology underlying dementia syndromes in older populations is complex. The contributions of Alzheimer's and Lewy body pathology are well appreciated. Recent studies with brain autopsies have highlighted the high prevalence of vascular disease as an independent, but often co-morbid contributor to dementia. The Adult Changes in Thought Study is a community-based, longitudinal study of brain aging and cognitive decline which has recently confirmed cerebral microinfarcts as a strong correlate of cognitive impairment and dementia. This study examines correlations between clinical characteristics including extensive, longitudinal medication histories, and longitudinal cognitive testing against structural and biochemical features of disease.

Blood pressure and brain injury in older adults: findings from a community-based autopsy study

OBJECTIVES

To examine correlations between blood pressure (BP) and dementia-related pathological brain changes in a community-based autopsy sample.

DESIGN

Prospective cohort study.

SETTING

A large health maintenance organization in Seattle, Washington.

PARTICIPANTS

A cohort of 250 participants aged 65 and older and cognitively normal at time of enrollment in the Adult Changes in Thought (ACT) Study and who underwent autopsy.

MEASUREMENTS

BP and history of antihypertensive treatment were taken at enrollment. A linear regression model was used to examine the relationship between BP (systolic (SBP) and diastolic (DBP)) at enrollment and pathological changes in the cerebrum (cystic macroscopic infarcts, microinfarcts, neuritic plaques, neurofibrillary tangles, and cortical Lewy bodies).

RESULTS

The presence of more than 2 microinfarcts, but not any other pathological change, was independently associated with SBP in younger participants (65-80, n=137) but not in older participants (>80, n=91). The relative risk (RR) for more than two microinfarcts with each 10-mmHg increase in SBP was 1.15 (95% confidence interval (CI)=1.00-1.33) in the younger participants, adjusted for age at entry, sex, and time to death. This RR was particularly strong in younger participants not taking antihypertensive medications (RR=1.48, 95% CI=1.21, 1.81); significant associations were not observed in participants treated for hypertension. Findings for DBP were negative.

CONCLUSION

The association between high SBP and cerebrovascular damage in untreated older adults (65-80) suggests that adequate hypertension treatment may reduce dementia risk by minimizing microvascular injury to cerebrum.

Pathological correlates of dementia in a longitudinal, population-based sample of aging

OBJECTIVE

Previously published community- or population-based studies of brain aging and dementia with autopsy were restricted to a single sex, a single ethnic group, Roman Catholic clergy, or focused pathological assessments. Our goal was to determine the independent pathological correlates associated with dementia in a typical US population.

METHODS

We evaluated autopsy data from the Adult Changes in Thought study, an ongoing longitudinal, population-based study of brain aging and dementia. Analyses were based on data collected from about 3,400 people 65 years or older who were cognitively intact at the time of enrollment in the Group Health Cooperative in King County, Washington. All consecutive autopsies (n = 221; 20% of deaths) from this cohort were evaluated and analyzed by weighted multivariate analysis to account for potential participation bias.

RESULTS

After adjusting for age, sex, education, and APOE, independent correlates of dementia (relative risk, 95% confidence interval; overall p value) included Braak stage (V/VI vs 0/I/II: 5.89, 1.62-17.60; p < 0.05), number of cerebral microinfarcts in standardized sections (>2 vs none: 4.80, 1.91-10.26; p < 0.001), and neocortical Lewy bodies (any vs none: 5.08, 1.37-18.96; p < 0.05). Estimates of adjusted population attributable risk for these three processes were 45% for Braak stage, 33% for microinfarcts, and 10% for neocortical Lewy bodies.

INTERPRETATION

Our results underscore the therapeutic imperative for Alzheimer's and Lewy body diseases, and provide evidence to support the immediate use of strategies that target cerebral microinfarcts as a means to partially prevent or delay the onset of dementia.

Proteomic identification of novel proteins in cortical lewy bodies

Lewy body (LB) inclusions are one of the pathological hallmarks of Parkinson's disease (PD) and dementia with Lewy bodies (DLB). One way to better understand the process leading to LB formation and associated pathogenesis responsible for neurodegeneration in PD and DLB is to examine the content of LB inclusions. Here, we performed a proteomic investigation of cortical LBs, obtained by laser capture microdissection from neurons in the temporal cortex of dementia patients with cortical LB disease. Analysis of over 2500 cortical LBs discovered 296 proteins; of those, 17 had been associated previously with brainstem and/or cortical LBs. We validated several proteins with immunohistochemical staining followed by confocal microscopy. The results demonstrated that heat shock cognate 71 kDa protein (also known as HSC70, HSP73, or HSPA10) was indeed not only colocalized with the majority of LBs in the temporal cortex but also colocalized to LBs in the frontal cortex of patients with diffuse LB disease. Our investigation represents the first extensive proteomic investigation of cortical LBs, and it is expected that characterization of the proteins in the cortical LBs may reveal novel mechanisms by which LB forms and pathways leading to neurodegeneration in DLB and/or advanced PD. Further investigation of these novel candidates is also necessary to ensure that the potential proteins in cortical LBs are not identified incorrectly because of incomplete current human protein database.

Lewy body pathology in familial Alzheimer disease: evidence for disease- and mutation-specific pathologic phenotype

BACKGROUND

The origin and significance of Lewy bodies and neurites (Lewy body pathology [LBP]) in Alzheimer disease (AD) are poorly understood.

OBJECTIVE

To examine LBP in the brainstem, limbic cortex, and neocortex of a large number of familial AD cases with mutations in 2 presenilin (PSEN) genes.

METHODS

Twenty-five familial AD cases with 9 known PSEN 1 mutations and 14 familial AD cases with a single PSEN 2 mutation (N141I) were examined for LBP using alpha-synuclein immunohistochemistry and sampling of multiple brainstem and cortical regions.

RESULTS

The amygdala was the most vulnerable site for LBP. In fact, virtually all (24 [96%] of 25 cases) of the PSEN 1 mutation cases had LBP in the amygdala. The PSEN 1 mutation cases also had more frequent LBP in the amygdala and neocortex than those with the PSEN 2 mutation. However, within families with a single mutation of either PSEN 1 or PSEN 2, there was frequent variability of the LBP.

CONCLUSION

These findings suggest that there are genetic influences on the presence of LBP in familial AD as demonstrated by the differences between PSEN 1 and PSEN 2 mutation cases.

Donepezil: a clinical review of current and emerging indications

This article reviews the piperidine derivative, donepezil hydrochloride (E2020, Aricept), a reversible central acetylcholinesterase inhibitor currently approved for treatment of mild-to-moderate Alzheimer's disease. Donepezil is well absorbed orally, unaffected by food or by time of administration; it reaches therapeutic levels in doses of 5-10 mg/day and peak plasma concentrations are obtained 3-4 h after oral administration. A single bedtime dose is recommended due to the long elimination half-life of the drug (70 h). Donepezil does not cause liver toxicity or significant drug interactions and is relatively well-tolerated. Initial side effects include nausea, vomiting, diarrhoea, insomnia, muscle cramps, fatigue, anorexia and syncope. Caution is advised in patients with bradycardia. Long-term use of donepezil in AD has been found to delay nursing-home placement and to result in caregiver respite. Donepezil also slows deterioration of cognition and global function in patients with moderate-to-severe AD, with improvement of abnormal behaviours. In addition to AD, donepezil demonstrates significant improvement in cognition, global function and activities of daily living in comparison with placebo-treated patients with vascular dementia and has potential therapeutic benefit for other neurological conditions.