Functional genomics and proteomics: application in neurosciences

Early Chronic Stress Induced Changes within the Locus Coeruleus in Sporadic Alzheimer's Disease

Chronic exposure to stress throughout the lifespan has been the focus of many studies on Alzheimer's disease (AD) because of the similarities between the biological mechanisms involved in chronic stress and the pathophysiology of AD. In fact, the earliest abnormality associated with the disease is the presence of phosphorylated tau protein in locus coeruleus neurons, a brain structure highly responsive to stress and perceived threat. Here, we introduce allostatic load as a useful concept for understanding many of the complex, interacting neuropathological changes involved in the AD degenerative process. In response to chronic stress, aberrant tau proteins that begin to accumulate within the locus coeruleus decades prior to symptom onset appear to represent a primary pathological event in the AD cascade, triggering a wide range of interacting brain changes involving neuronal excitotoxicity, endocrine alterations, inflammation, oxidative stress, and amyloid plaque exacerbation. While it is acknowledged that stress will not necessarily be the major precipitating factor in all cases, early tau-induced changes within the locus coeruleus-norepinephrine pathway suggests that a therapeutic window might exist for preventative measures aimed at managing stress and restoring balance within the HPA axis.

Neuroticism alters the transcriptome of the frontal cortex to contribute to the cognitive decline and onset of Alzheimer's disease

Accumulating evidence has suggested that the molecular transcriptional mechanism contributes to Alzheimer's disease (AD) and its endophenotypes of cognitive decline and neuropathological traits, β-amyloid (Aβ) and phosphorylated tangles (TAU). However, it is unknown what is the impact of the AD risk factors, personality characteristics assessed by the NEO Five-Factor Inventory, on the human brain's transcriptome. Using postmortem human brain samples from 466 subjects, we found that neuroticism has a significant overall impact on the brain transcriptome (omnibus P = 0.005) but not the other four personality characteristics. Focused on those cognitive decline related gene co-expressed modules, neuroticism has nominally significant associations (P < 0.05) with four neuronal modules, which are more related to PHFtau than Aβ across all eight brain regions. Furthermore, the effect of neuroticism on cognitive decline and AD might be mediated through the expression of module 7 and TAU pathology (P = 0.008). To conclude, neuroticism has a broad impact on the transcriptome of human brains, and its effect on cognitive decline and AD may be mediated through gene transcription programs related to TAU pathology.

Social Network Position Moderates the Relationship between Late-life Depressive Symptoms and Memory Differently in Men and Women

Late-life depression has been considered to be associated with memory deficits and hippocampal volume reduction. Considering that not all depression patients undergo the same amount of cognitive impairment or regional brain volume loss, moderating factors such as complex mental activity and social activity have been examined to assess whether these factors attenuate the detrimental impact of depressive symptoms on cognitive function and regional brain volume. However, the premise that a cognitively stimulating experience may modify the association between depressive symptoms and memory or hippocampal volume has not been investigated using social network data, which would reflect individuals' concrete characteristic of everyday social activity. In a social network, a brokerage position which connects two otherwise unconnected others demands mental and physical efforts. Using complete social network data in an entire village in South Korea, we examined whether opportunities for brokerage in social networks alter the negative association between depressive symptoms and episodic memory function or hippocampal volume in older adults. Initially, 125 participants were included in the analysis involving episodic memory function. Then, of which 65 participants completed the MRI scan, and were included in the subsequent analysis containing the hippocampal volume. Furthermore, we investigated the gender-specific effect of brokerage based on the previously reported gender difference in the effect of social networks. We found a gender-specific moderating effect of brokerage. For men, a large opportunity for brokerage weakened the negative association between depressive symptoms and memory performance and left hippocampal volume. In contrast, women showed that a large opportunity for brokerage was not beneficial for assuaging the impact of depressive symptoms on memory performance and hippocampal volume. In women, the opportunity for brokerage was positively associated with the detrimental impact of depressive symptoms on memory performance and hippocampal volume. Our findings suggest that occupying a bridging position in a social network may minimize the impact of depressive symptoms on memory function and hippocampal volume among older men, whereas the opposite holds true for older women.

Effect of Antidepressant Medication Use and Social Engagement on the Level of Depressive Symptoms in Community-Dwelling, Older African Americans and Whites With Dementia

Objective: This study examines the effect of antidepressant medication use and social engagement on the level of depressive symptoms at the time of initially meeting criteria for dementia. Method: Measures of social engagement, medication use, and depressive symptoms from 402 participants with incident dementia were utilized for the study. Proportional odds models adjusted for demographics were constructed with depressive symptoms as the outcome and social network size, perceived social isolation, and antidepressant medication use as independent variables. Results: Each additional person in the social network was associated with a lower depressive symptom score, odds ratio (OR) = 0.93, 95% confidence interval (CI) = [0.90, 0.97], p ≤ .01, and each unit increase in perceived social isolation was associated with a higher depressive symptom score (OR = 4.14, 95% CI = [2.94, 5.85], p ≤ .01). No association was found between antidepressant medication use and depressive symptom score. Discussion: Depression management at the time of dementia diagnosis should probably be directed toward increasing social engagement in older adults.

Novel Vilazodone-Tacrine Hybrids as Potential Multitarget-Directed Ligands for the Treatment of Alzheimer's Disease Accompanied with Depression: Design, Synthesis, and Biological Evaluation

Depression is one of the most frequent psychiatric complications of Alzheimer's disease (AD), affecting up to 50% of the patients. A novel series of hybrid molecules were designed and synthesized by combining the pharmacophoric features of vilazodone and tacrine as potential multitarget-directed ligands for the treatment of AD with depression. In vitro biological assays were conducted to evaluate the compounds; among the 30 hybrids, compound 1e showed relatively balanced profiles between acetylcholinesterase inhibition (IC₅₀ = 3.319 ± 0.708 μM), 5-HT_1A agonist (EC₅₀ = 107 ± 37 nM), and 5-HT reuptake inhibition (IC₅₀ = 76.3 ± 33 nM). Compound 1e displayed tolerable hepatotoxicity and moderate hERG inhibition activity, and could penetrate the blood-brain barrier in vivo. Furthermore, an oral intake of 30 mg/kg 1e·HCl could significantly improve the cognitive function of scopolamine-induced amnesia mice and alleviate the depressive symptom in tail suspension test. The effectivity of 1e validates the rationality of our design strategy.

Differential Expression of Serum Proteins in Rats with Allergic Asthma: A Study Based on the Nanoliter Two-Dimensional Liquid Chromatography Technique

Objective. To investigate the pathogenesis of allergic asthma via the nanoliter two-dimensional liquid chromatography (nano-2D-LC) technique. Method. 24 Wistar rats were randomized into 3 groups: the blank-control group (A), the restrained group (B), and the asthma model group (C). The nanoliter two-dimensional liquid chromatography (nano-2D-LC) technique was used to study the differential protein expressions of the serum in asthmatic rats. Results. Compared with the restrained group, the data from the asthma model group displayed a distinctive peak, that is, peak number 13 (94.731 min). The data also displayed three missing peaks in the asthma group, that is, peak number 1 (77.489 min), peak number 2 (78.418 min), and peak number 5 (80.533 min), suggesting that the corresponding peptides might be related to the pathogenesis of asthma. Compared with the blank-control group, the restrained group showed 4 new peaks, that is, peak number 2 (78.418 min), peak number 4 (79.398 min), peak number 5 (80.533 min), and peak number 7 (81.824 min). The restrained group also displayed a missing peak, that is, peak number 3 (78.804 min), indicating that those 5 polypeptides might be related to the binding-induced stress stimuli. Conclusion. The study suggests that the pathogenesis of allergic asthma is closely related to abnormal levels of proteins; however, future animal experiments should identify the specific protein expressions caused by stress factors.

Depressive Symptoms, Cognition, and Everyday Function Among Community-Residing Older Adults

OBJECTIVE

The aim of this study was to understand the relationships among depressive symptoms, cognition, and functional performance in a community-based sample of older adults.

METHOD

Older adults ( N = 885) from the Staying Keen in Later Life study completed tests of executive function, speed of processing, and memory. The Center for Epidemiologic Depression Scale assessed depressive symptoms. The Timed Instrumental Activities of Daily Living Test assessed participants' everyday functional performance.

RESULTS

Depressive symptoms had significant associations with measures of executive function, speed of processing, memory, and everyday functional performance. Cognitive performance completely mediated the association between depressive symptoms and everyday function.

DISCUSSION

Among community-dwelling older adults, depressive symptoms were associated with impaired cognition across multiple domains, which detrimentally affected everyday function. Health care providers should be aware of these associations to monitor and manage changes in depressive symptoms and cognitive performance and thereby potentially mitigate functional decline.

How does cognitive reserve impact on the relationships between mood, rumination, and cognitive function in later life?

OBJECTIVES

Higher levels of cognitive reserve (CR) are associated with better cognitive function in later life. In contrast, depressive symptoms, anxiety, and rumination are associated with diminished cognitive function. There has been limited research to date examining the influence of CR on the relationship between mood and cognitive function, and results are inconsistent. The aim of this study was to investigate the role CR plays in the relationships between mood, rumination, and cognitive function in later life.

METHOD

Two hundred and thirty-six healthy people aged 60+ completed measures of CR, depression, anxiety, rumination, recall, and verbal fluency. Participants were dichotomised at the median into those with lower and higher levels of CR.

RESULTS

CR, mood, and rumination together accounted for between 13% and 15.6% of the variance in scores on the cognitive tasks in the sample as a whole. Mood and rumination explained a significant amount of variance in cognitive test scores in those with lower levels of CR, but not in those with higher levels of CR.

CONCLUSION

The way in which mood and rumination are related to cognitive function differs depending on the individual's level of CR. These results support the view that it is important to continue to build on CR as people move into later life in order to maintain cognitive health.

Effects of exercise and horticultural intervention on the brain and mental health in older adults with depressive symptoms and memory problems: study protocol for a randomized controlled trial [UMIN000018547]

Background

Depressive symptoms and memory problems are significant risk factors for dementia. Exercise can reduce depressive symptoms and improve cognitive function in older people. In addition, the benefits of horticultural activity on physical and mental well-being have been demonstrated in people with dementia. Although evidence of such non-pharmacological interventions is mounting, no studies have examined whether physical exercise and horticultural activity exert a positive impact on brain and mental health (e.g., depressive symptoms) in non-demented older adults at high risk of cognitive impairment and depression. Therefore, we propose a randomized controlled trial to assess the efficacy and efficiency of physical exercise and horticultural activity in improving brain and mental health in community-dwelling older adults with memory problems and depressive symptoms.

Methods/Design

The 20-week randomized controlled trial will include 90 community-dwelling adults aged 65 years or older with memory problems and depressive symptoms. Participants will be randomized to one of three experiments: exercise, horticultural activity, or educational control group, using a 1:1:1 allocation ratio. The combined exercise program and horticultural activity program will consist of 20 weekly 90-minute sessions. Participants in the exercise group will practice aerobic exercise, muscle strength training, postural balance retraining, and dual-task training. The horticultural activity program will include crop-related activities, such as field cultivation, growing, and harvesting. Participants in the educational control group will attend two 90-minute educational classes during the 6-month trial period. Depressive symptoms and memory performance will be measured by the Geriatric Depression Scale-15, and the Logical Memory subtests of the Wechsler Memory Scale-Revised will be used to measure depressive symptoms and memory performance as primary outcomes, at baseline (prior to randomization), immediately following intervention (6 months from baseline), and 6 months after intervention. Hippocampal volume will be measured at baseline and immediately after intervention, using magnetic resonance imaging. Secondary outcomes will comprise cognitive function, including language, attention/executive performance, and processing speed; brain-derived neurotrophic-factor serum levels; and health-related quality of life.

Discussion

This intervention study will determine the clinical importance and efficacy of physical exercise and horticultural activity as non-pharmacological interventions in community-dwelling older adults at high risk of poor brain and mental health.

Trial registration

UMIN000018547; registered 7 August 2015.

Behavioral Competence and Emotional Well-Being of Older Adults with Mild Cognitive Impairment

We examined whether older individuals with mild cognitive impairment (MCI) differed from healthy controls (HC) and persons with dementia (AD) in objective and perceived behavioral competence as well as in emotional well-being. We used a merged sample of 257 older adults aged 59 to 91 years (M = 72.9; SD = 6.4) stemming from Israel and Germany. Objective behavioral competence (assessed based on global positioning system (GPS)-based tracking data and a structured questionnaire) of MCI individuals was mostly similar to the HC group. Regarding perceived behavioral competence and emotional well-being, MCI individuals were more similar to the AD group and below the HC group’s mean levels. Findings suggest that a differentiated view of MCI individual’s competence and emotional well-being is in place.

Personality traits and behavioural and psychological symptoms in patients with mild cognitive impairment

BACKGROUND AND AIMS

Both personality changes and behavioural and psychological symptoms (BPS) may be associated with mild cognitive impairment (MCI) in later life and help identify incipient dementia. We wished to investigate the links between personality and BPS in MCI.

METHOD

We studied premorbid personality traits as estimated 5 years back and their changes in 83 control subjects and 52 MCI patients using the revised NEO Personality Inventory for the Five-Factor Model completed by a proxy. Information on BPS was obtained using the Neuropsychiatric Inventory (NPI). Analyses were controlled for current depression and anxiety.

RESULTS

Premorbid neuroticism and openness to experience were associated with the total NPI score. The changes in neuroticism, extraversion, openness to experiences, and conscientiousness were associated with apathy and affective symptoms.

CONCLUSIONS

Personality changes and BPS occur in MCI. The occurrence of affective BPS and apathy is associated with both premorbid personality traits and their changes.

Cognitive dysfunction with aging and the role of inflammation

As the average lifespan continues to climb because of advances in medical care, there is a greater need to understand the factors that contribute to quality of life in the elderly. The capacity to live independently is highly significant in this regard, but is compromised by cognitive dysfunction. Aging is associated with decreases in cognitive function, including impairments in episodic memory and executive functioning. The prefrontal cortex appears to be particularly vulnerable to the effects of advancing age. Although the mechanism of age-related cognitive decline is not yet known, age-related inflammatory changes are likely to play a role. New insights from preclinical and clinical research may give rise to novel therapeutics which may have efficacy in slowing or preventing cognitive decline with advancing age.

Monitoring CSF proteome alterations in amyotrophic lateral sclerosis: obstacles and perspectives in translating a novel marker panel to the clinic

Background

Amyotrophic lateral sclerosis (ALS) is a fatal disorder of the motor neuron system with poor prognosis and marginal therapeutic options. Current clinical diagnostic criteria are based on electrophysiological examination and exclusion of other ALS-mimicking conditions. Neuroprotective treatments are, however, most promising in early disease stages. Identification of disease-specific CSF biomarkers and associated biochemical pathways is therefore most relevant to monitor disease progression, response to neuroprotective agents and to enable early inclusion of patients into clinical trials.

Methods and Findings

CSF from 35 patients with ALS diagnosed according to the revised El Escorial criteria and 23 age-matched controls was processed using paramagnetic bead chromatography for protein isolation and subsequently analyzed by MALDI-TOF mass spectrometry. CSF protein profiles were integrated into a Random Forest model constructed from 153 mass peaks. After reducing this peak set to the top 25%, a classifier was built which enabled prediction of ALS with high accuracy, sensitivity and specificity. Further analysis of the identified peptides resulted in a panel of five highly sensitive ALS biomarkers. Upregulation of secreted phosphoprotein 1 in ALS-CSF samples was confirmed by univariate analysis of ELISA and mass spectrometry data. Further quantitative validation of the five biomarkers was achieved in an 80-plex Multiple Reaction Monitoring mass spectrometry assay.

Conclusions

ALS classification based on the CSF biomarker panel proposed in this study could become a valuable predictive tool for early clinical risk stratification. Of the numerous CSF proteins identified, many have putative roles in ALS-related metabolic processes, particularly in chromogranin-mediated secretion signaling pathways. While a stand-alone clinical application of this classifier will only be possible after further validation and a multicenter trial, it could be readily used to complement current ALS diagnostics and might also provide new insights into the pathomechanisms of this disease in the future.

Premorbid personality traits and their course in mild cognitive impairment: results from a prospective population-based study in Germany

BACKGROUND

Personality traits contribute to cognitive functioning. We present a study comparing personality traits in normal ageing and mild cognitive impairment (MCI).

METHODS

We conducted a representative longitudinal study including 222 subjects from a cohort born between 1930 and 1932 (n = 500) examined at three examination waves (t1: 1993/1994; t2: 1997/1998; t3: 2005/2007). Personality traits were assessed with the NEO-Five-Factor Inventory questionnaire.

RESULTS

Healthy controls and patients with MCI showed a significant (p < 0.05) decrease concerning their levels of neuroticism and extraversion over time. MCI subjects scored significantly higher on neuroticism at baseline and lower on openness at all examinations compared to healthy controls. Subjects with higher baseline neuroticism showed a 2.24 times higher risk of developing MCI at the third follow-up (odds ratio = 2.24, 95% confidence interval = 1.12-4.45 - scores adjusted for education and sex).

CONCLUSIONS

MCI subjects differ in their premorbid personality traits compared to healthy controls. According to our study, higher neuroticism should be considered a risk factor for the development of MCI.

Multistrategic memory training with the metamemory concept in healthy older adults

OBJECTIVE

According to the increase of older people, the need for effective methods to maintain or improve cognitive functions in the elderly has increased. These cognitive enhancing methods may contribute to the prevention of elderly cognitive decline by aging and dementing illness as well. This study aimed to examine the effectiveness of multistrategic memory training with the metamemory concept on cognitive functions in the normal health elderly in Korea.

METHODS

The program used in this study was developed by psychiatrists and psychologists in accordance with Korean situations. We applied the training program to the community-dwelling elderly with subjective memory complaints. Twenty participants were randomly received the intervention with 20 non-treatment controls. This program consisted of 10 sessions and was administered once a week. We examined the effects of this memory training for verbal memory, visuospatial memory, working memory, and verbal fluency ability by repeated ANOVA.

RESULTS

There were significant improvements in Word List Short-term Delayed Free and Cued Recall, Word list Long-term Delayed Free and Cued Recall and visuospatial recognition memory. Performance improvements in visuospatial span forwards and the Categorical Fluency Test were also significant. These improvements were still significant after adjusting for depression improvement exact categorical fluency.

CONCLUSION

This study shows that multistrategic memory training with the metamemory concept may improve memory ability and other cognitive functions which are not trained and that these improvements may be achieved by pure cognitive training effects.

BDNF-trkB signaling in late life cognitive decline and Alzheimer’s disease

Expression levels of BDNF and trkB, primary components of an important neurotrophin signaling pathway, have been reported to be abnormal in neurodegenerative dementias. Here, we used a novel postmortem brain tissue stimulation paradigm to examine BDNF-induced trkB signaling in participants of the Religious Orders Study, a large longitudinal clinicopathological study of aging and cognition. Thawed slices of anterior cingulate cortex were incubated in BDNF and changes in phosphorylated trkB and downstream signaling molecules ERK2 and Akt were measured, as well as the association of NMDA receptors with trkB. We found that stimulation with BDNF induced much greater activity of the BDNF-trkB signaling pathway in brain tissues of people with cognitive decline and AD, as evidenced by significantly more phosphorylation of trkB (pY-trkB), ERK2 (pY/pT-ERK2), Akt (pS-Akt), and greater BDNF-induced coupling of trKB with NMDAR2A/B. These findings were independent of PHFtau neurofibrillary tangle and amyloid-b plaque densities and other potentially confounding variables. Regression analyses with clinical features further characterized significant relationships between measures of BDNF-trkB activation and domains of cognition and emotional functioning. Increased BDNF-trkB signaling with cognitive decline could reflect a primary derangement of pathway functioning or a compensatory neuroplastic response to counteract neural injury associated with neurodegenerative processes.

Handwriting process variables among elderly people with mild Major Depressive Disorder: a preliminary study

BACKGROUND AND AIMS

Despite evidence of cognitive impairment and difficulties in performing daily activities among elderly people with major depression, studies implementing objective performance-based evaluation of functional deficits in this patient population are scarce. With the aid of a computerized device we examined functional handwriting performance among elderly patients with mild Major Depressive Disorder (MDD) in comparison with controls.

METHODS

Participants were 20 elderly participants with mild MDD and 20 matched controls. Both groups performed four functional writing tasks with a computerized system. Kinematic measures were: in-air time per stroke (temporal), stroke width (spatial), pressure applied (pressure).

RESULTS

A MANOVA yielded statistically significant between-groups differences for the four writing tasks across the temporal, spatial and pressure measures. A univariate ANOVA revealed that the significance was due to differences between mild MDD and controls on the pressure measure in all four tasks. Moderately significant correlations were found in all tasks between in-air time and pressure while writing and the GDS score, and between the in-air time of three tasks (except writing one's name) and the Mini-Mental State Examination (MMSE) score. Handwriting pressure, and temporal and spatial measures of the task of writing one's name allowed us to classify 84.2% of the participants correctly.

CONCLUSIONS

Computerized evaluation of handwriting, a daily task, was found to be sensitive to altered performance among participants with mild MDD, and was correlated with cognitive impairment and depression status. The theoretical importance and practical implications of handwriting process measures are discussed.

Social engagement and cognitive function in old age

We examined the association of diverse measures of social engagement with level of function in multiple cognitive domains in 838 persons without dementia who had a mean age of 80.2 (SD = 7.5). Social network size, frequency of social activity, and level of perceived social support were assessed in linear regression models adjusted for age, sex, education, and other covariates. Social activity and social support were related to better cognitive function, whereas social network size was not strongly related to global cognition. The results confirm that higher level of social engagement in old age is associated with better cognitive function but the association varies across domains of social engagement.

Obesity and central obesity as risk factors for incident dementia and its subtypes: a systematic review and meta-analysis

While dementia affects 6-10% of persons 65 years or older, industrialized countries have witnessed an alarming rise in obesity. However, obesity's influence on dementia remains poorly understood. We conducted a systematic review and meta-analysis. PUBMED search (1995-2007) resulted in 10 relevant prospective cohort studies of older adults (40-80 years at baseline) with end points being dementia and predictors including adiposity measures, such as body mass index (BMI) and waist circumference (WC). There was a significant U-shaped association between BMI and dementia (P = 0.034), with dementia risk increased for obesity and underweight. Pooled odds ratios (OR) and 95% confidence intervals (CI) for underweight, overweight and obesity compared with normal weight in relation to incident dementia were: 1.36 (1.07, 1.73), 0.88 (0.60, 1.27) and 1.42 (0.93, 2.18) respectively. Pooled ORs and 95% CI for obesity and incident Alzheimer's disease (AD) and vascular dementia were 1.80 (1.00, 3.29) vs. 1.73 (0.47, 6.31) and were stronger in studies with long follow-up (>10 years) and young baseline age (<60 years). Weight gain and high WC or skin-fold thickness increased risks of dementia in all included studies. The meta-analysis shows a moderate association between obesity and the risks for dementia and AD. Future studies are needed to understand optimal weight and biological mechanisms.

Application of proteomic technology in eye research: a mini review

Proteomics is a rapidly growing research area for the study of the protein cognate of genomic data. This review gives a brief overview of the modern proteomic technology. In addition to general applications of proteomics, we highlight its contribution to studying the physiology of different ocular tissues. We also summarise the published proteomic literature in the broad context of ophthalmic diseases, such as cataract, age-related maculopathy, diabetic retinopathy, glaucoma and myopia. The proteomic technology is a useful research tool and it will continue to advance our understanding of a variety of molecular processes in ocular tissues and diseases.

Cognitive performance in elderly women: significance of the 19bp insertion/deletion polymorphism in the 5' flank of the dopamine beta-hydroxylase gene, educational level, body fat measures, serum triglyceride, alcohol consumption and age

BACKGROUND

Genetic and environmental factors influence cognitive aging. The gene encoding dopamine beta-hydroxylase (DBH) could be one such factor since this hydroxylase converts dopamine to norepinephrine both of which are involved in cognition regulation.

OBJECTIVE

To assess the effect of the 19bp insertion/deletion polymorphism in the 5' flank of the DBH gene on cognitive performance in elderly women relative to other factors of cognitive aging.

METHODS

We examined a cross-sectional sample of 1371 postmenopausal women. Cognitive abilities were assessed by the 6-item orientation-memory-concentration test. The 19bp insertion/deletion polymorphism of the DBH gene was genotyped and apolipoprotein E (APOE) epsilon4 allele status was determined. In addition blood pressure, body fat mass and blood lipids were measured. Information was also obtained by personal interviews. Data were analyzed by regression analysis.

RESULTS

Cognition was univariately associated with DBH genotype (p = 0.04). A univariate association of borderline significance was observed for APOE epsilon4 allele status (p = 0.07). Exclusion of women with severe cognition impairment did not alter the strength of the association with the DBH gene polymorphism markedly (p = 0.06) but obliterated the weak association between APOE epsilon4 allele status and cognition. The association of the DBH gene polymorphism with cognition persisted after adjustment for other variables (p = 0.03).

CONCLUSIONS

The 19bp insertion/deletion polymorphism of the DBH gene influences cognition in elderly women and might have a stronger effect than APOE epsilon4 allele status on mild cognitive impairment. Both genetic polymorphisms had a significantly smaller impact on cognition than age, education, alcohol consumption and body fat measures.

Association between lifestyle activity and depressed mood among home-dwelling older people: a community-based study in Japan

In the community-based cross-sectional study, we investigated patterns of lifestyle activities among older people and examined the association between specific types of lifestyle activity and depressed mood status. The participants were 656 men and women aged 65 or older in 2004 who lived in a rural town in Japan, neither institutionalized nor hospitalized and who did not have symptoms of dementia. We found that less interaction with neighbors, society and friends was highly associated with depressed mood for men. Additionally, although they were physically active in gardening/farming, it did not necessarily mean that they were mentally healthy if they did not have close ties with friends, family and children/grandchildren. For women, it seemed important to engage in several types of activities relating to society, leisure and children/grandchildren to be in less depressed mood. Even if they were socially inactive, if they had frequent contact with family and children/grandchildren or going out for pleasure they were less likely to be depressed. Distinguishing gender differences in lifestyle activity patterns and the association of activities with depressed mood will help to guide the development of depression intervention programs.

Depressive symptoms and cognitive change in older Mexican Americans

To examine the association between presence of clinically relevant depressive symptoms (Center for Epidemiologic Studies Depression Scale [CES-D] score >or= 16) and subsequent cognitive function (Mini-Mental State Examination [MMSE]) over a 7-year period in older Mexican Americans, a prospective cohort study was performed. Five south-western states contributed data to the Hispanic Established Populations for Epidemiologic Studies of the Elderly. Participants included 2812 noninstitutionalized Mexican Americans aged 65 and older followed from 1993-1994 until 2000-2001. Cognitive change was assessed using the MMSE at baseline and at 2, 5, and 7 years of follow-up. Independent variables were sociodemographics, CES-D >or= 16, medical conditions (hypertension, diabetes, coronary artery disease, and stroke), and activities of daily living (ADL) status. A general linear mixed model was used to estimate cognitive change. There was a cross-sectional association between CES-D >or= 16 and lower MMSE score (estimate = -0.48; standard error [SE] = 0.15; P < .01), independent of age, gender, education, marital status, time of interview, ADL limitations, vision impairment, and medical conditions. In the fully adjusted longitudinal model, subjects with clinically relevant depressive symptoms had a greater decline in MMSE score over 7 years than those without clinically relevant depressive symptoms (estimate = -0.17; SE = 0.05; P < .001), adjusting for sociodemographics, ADL and medical conditions. Each point increase in the CES-D score was associated with a decline of 0.010 point in MMSE score per year (SE = 0.002; P < 0.0001), adjusting for relevant confounders. Presence of clinically relevant depressive symptoms was associated with subsequent decline in cognitive function over 7 years in older Mexican Americans, independent of demographic and health factors.

Understanding proteomics

The purpose of this article is to describe proteomics, to discuss the importance of proteomics, to review different methods for protein measurement, and to illustrate how knowledge of proteomics might improve patient care. Among common laboratory determinations are those involving enzymatic (protein) function. Although the presence or activity of proteins may be seen clinically as incidental, proteins represent the engines through which critical life processes ensue. A selected review of the literature is presented to define and explain proteomics and to review the various techniques to measure proteins. A case-study approach is used to illustrate how proteomics can be utilized for detecting and monitoring disease. The human genome has been completely sequenced and proteomics has emerged as a way to unravel the biochemical and physiological mechanisms of diseases at the functional level. This review includes the recent discoveries regarding proteomics and its importance in the detection and treatment of disease.

Depressive symptoms, major depressive episode and cognition in the elderly: the three-city study

OBJECTIVES

The relationship between depression and dementia in the elderly has been extensively studied but the tools used to define depressed subjects are heterogeneous between studies. The objective of this study was to examine the relationship between depression and cognitive performances by using multiple measures of depressive state.

METHODS

A sample of 7,869 nondemented community-dwelling persons aged >or=65 years participated in the study. Depressive symptoms were evaluated by the Center for Epidemiological Study Depression Scale and the Mini-International Neuropsychiatric Interview was used to assess history of major depressive episodes (MDE). Cognitive function was evaluated by several tests including the Mini-Mental State Examination (MMSE), Trail Making Test, Isaacs Set Test and Benton Visual Retention Test.

RESULTS

When studied in separate models, depressive symptoms were significantly related to lower cognitive performances for all neuropsychological tests after adjusting for potential confounders (p<0.0001), whereas subjects with current MDE had significantly lower performances in MMSE and Isaacs Set Test. When studied concomitantly, only high levels of depressive symptoms were related to lower cognitive performance, whereas existence of MDE (past or current) was no longer associated with cognitive performances.

CONCLUSIONS

These data suggest that once current depressive symptoms are taken into account, major depression (past or current) is not associated with lower cognitive performances in a community-based sample of elderly people aged >or=65 years.

Subjective memory complaints and cognitive impairment in older people

Subjective memory complaints (SMCs) are common in older people and are often thought to indicate cognitive impairment. We reviewed research on the relationship between SMCs and (a) current cognitive function, (b) risk of future cognitive decline, and (c) depression and personality. SMCs were found to be inconsistently related to current cognitive impairment but were more strongly related to risk of future cognitive decline. However, SMCs were consistently related to depression and some personality traits, e.g. neuroticism. In conclusion, the determinants of SMCs are complex. The utility of SMCs in the diagnosis of pre-dementia states (e.g. mild cognitive impairment) is uncertain and requires further evaluation.

Depressive symptoms associated with hereditary Alzheimer's disease: a case description

The authors describe a family group studied by the Centro de Biología Molecular y Biotecnología, and the Clínica de la Memoria, las Demencias y el Envejecimiento (Universidad Tecnológica de Pereira, Colombia), and evaluate the association of depressive symptoms with Alzheimer's disease (AD). This family presented a hereditary pattern for AD characterized by an early onset of dementia symptoms, a long preclinical depressive course, and, once the first symptoms of dementia appeared, a rapid progression to severe cognitive function impairment. The authors found a high prevalence of depressive symptoms in this family and propose that the symptoms could be an important risk factor for developing AD in the presence of other risk factors such as the APOE E4 allele.

Blood-brain barrier genomics and proteomics: elucidating phenotype, identifying disease targets and enabling brain drug delivery

The blood-brain barrier (BBB) regulates the passage of material between the bloodstream and the brain. Recent genomic and proteomic studies of the BBB have identified some of the unique molecular characteristics of this vascular bed, and have reinforced the concept that the BBB is heavily involved in brain function. Genomic and proteomic techniques have also been used to analyze the molecular events underlying diseases that have BBB involvement, such as multiple sclerosis, Alzheimer's disease, stroke and HIV-1 infection. It is expected that a better understanding of the complex mechanisms that link the BBB to neurological disease will ultimately lead to the development of innovative treatments.

Chronic distress, age-related neuropathology, and late-life dementia

OBJECTIVE

The objective of this study was to test whether common age-related neuropathology could account for the relation of chronic distress to dementia.

METHODS

In a selected cohort of more than 1000 older Catholic clergy members undergoing annual clinical evaluations, 326 persons died, of whom 306 (94%) underwent brain autopsy, the results of which were available in 219 (mean age at death = 85.4, standard deviation [SD] = 6.6; mean postmortem interval = 7.6 hours, SD = 6.9). A composite measure of chronic distress was constructed from standard measures of two traits, neuroticism and anxiety proneness, completed at baseline, and of depressive symptoms, completed annually. Dementia was diagnosed according to standard criteria and cognition was assessed with previously established composite measures based on a uniform clinical evaluation that took place a mean of 9.1 months before death (SD = 9.5). On postmortem examination, levels of amyloid-beta and tau-positive neurofibrillary tangles and the presence of Lewy bodies were quantified in six brain regions, and the number and location of chronic cerebral infarctions were noted.

RESULTS

In analyses that controlled for age, sex, education, amyloid, tangles, Lewy bodies, and cerebral infarction, higher level of chronic distress was associated with a higher likelihood of dementia and lower level of cognition proximate to death. Chronic distress was not correlated with any form of neuropathology, including limbic, neocortical, and global indices, and did not modify the association of pathology with cognition.

CONCLUSIONS

Chronic psychological distress is associated with late-life dementia but not with its leading causes, suggesting that novel neurodeteriorative mechanisms may be involved.

Is lower cognitive function in one spouse associated with depressive symptoms in the other spouse?

This study examines whether lower cognitive function in one spouse is associated with depressive symptoms in the other spouse. The subjects were 528 community-dwelling spouse pairs aged 65+ who participated in the Chicago Health and Aging Project (CHAP), an ongoing longitudinal, bi-racial, population-based study of risk factors for incident Alzheimer's disease and other age-related chronic conditions. CHAP participants were assessed at 3-year intervals over a period of nearly ten years. The results show a cross-sectional association of wives' lower cognitive function at baseline with depressive symptoms in husbands; however, husbands' cognitive function was not associated with wives' depressive symptoms. There was no longitudinal association of cognitive function at baseline with increased depressive symptoms over time. Furthermore, change in cognitive function over time had no effect on depressive symptoms in either spouse. The relationship between cognitive function and depressive symptoms in spouse pairs is complex. Our findings suggest that husbands may be particularly psychologically vulnerable to the negative effects of their wives' cognitive impairment. This vulnerability may have a range of long-term health and caregiving implications.

Chronic psychological distress and risk of Alzheimer's disease in old age

Clinical and pathological data from the Rush Memory and Aging Project were used to test the hypothesis that distress proneness is associated with increased risk of Alzheimer's disease (AD). More than 600 older persons without dementia completed a 6-item measure of neuroticism, a stable indicator of proneness to psychological distress. At annual intervals thereafter, they underwent uniform evaluations that included clinical classification of AD and administration of 18 cognitive tests. Those who died underwent brain autopsy from which composite measures of AD pathology were derived. During a mean of about 3 years of follow-up, 55 people were clinically diagnosed with AD. In analyses that controlled for age, sex, and education, persons with a high level of distress proneness (score = 24, 90th percentile) were 2.7 times more likely to develop AD than those not prone to distress (score = 6, 10th percentile). Adjustment for depressive symptomatology or frequency of cognitive, social, and physical activity did not substantially change this effect. Distress proneness was also associated with more rapid cognitive decline. Among 45 participants who died and underwent brain autopsy, distress proneness was unrelated to diverse measures of AD pathology and was inversely related to cognition after controlling for AD pathology. The results support the hypothesis that distress proneness is associated with increased risk of dementia and suggest that neurobiologic mechanisms other than AD pathology may underlie the association.

Liquid chromatography with tandem mass spectrometry-based proteomic discovery in aging and Alzheimer's disease

Systems biology offers enormous potential to understand the complexity of human brain aging and neurodegenerative diseases. Proteomics has an important role in these investigations because of its unique strengths and because of the potential central pathogenic contribution of pathological protein to several of these diseases. Here we have reviewed the methods and presented some examples of liquid chromatography-electrospray ionization-tandem mass spectrometry-based proteomics, with and without quantification using isotope-coded affinity tags, in the investigation of aging and Alzheimer's disease. As protocols and methods for improved quantitative high-throughput proteomics constantly improve, this approach will likely continue to provide deeper insight into human brain aging and neurodegenerative diseases.

Stress-related cognitive interference predicts cognitive function in old age

Both subjective distress and cognitive interference have been proposed as mechanisms underlying the negative effects of stress on cognition. Studies of aging have shown that distress is associated with lower cognitive performance, but none have examined the effects of cognitive interference. One hundred eleven older adults (M-sub(age)=80) completed measures of working memory, processing speed, and episodic memory as well as self-report measures of subjective distress and cognitive interference. Cognitive interference was strongly associated with poorer performance on all 3 cognitive constructs, whereas distress was only modestly associated with lower working memory. The results suggest that cognitive process related to stress is an important predictor of cognitive function in advanced age.

National Institute of Neurological Disorders and Stroke-Canadian Stroke Network vascular cognitive impairment harmonization standards

BACKGROUND AND PURPOSE

One in 3 individuals will experience a stroke, dementia or both. Moreover, twice as many individuals will have cognitive impairment short of dementia as either stroke or dementia. The commonly used stroke scales do not measure cognition, while dementia criteria focus on the late stages of cognitive impairment, and are heavily biased toward the diagnosis of Alzheimer disease. No commonly agreed standards exist for identifying and describing individuals with cognitive impairment, particularly in the early stages, and especially with cognitive impairment related to vascular factors, or vascular cognitive impairment.

METHODS

The National Institute for Neurological Disorders and Stroke (NINDS) and the Canadian Stroke Network (CSN) convened researchers in clinical diagnosis, epidemiology, neuropsychology, brain imaging, neuropathology, experimental models, biomarkers, genetics, and clinical trials to recommend minimum, common, clinical and research standards for the description and study of vascular cognitive impairment.

RESULTS

The results of these discussions are reported herein.

CONCLUSIONS

The development of common standards represents a first step in a process of use, validation and refinement. Using the same standards will help identify individuals in the early stages of cognitive impairment, will make studies comparable, and by integrating knowledge, will accelerate the pace of progress.

Cognitive impairment in elderly women: the relative importance of selected genes, lifestyle factors, and comorbidities

BACKGROUND

A variety of factors contribute to the development of cognitive impairment in elderly people. Previous studies have focused upon a single or a few risk factors. In this study we assessed and compared the significance of a wide variety of potential risk factors for cognitive impairment in postmenopausal women.

METHODS

A total of 208 pairs of elderly women (mean age = 73.2 years) were examined in a cross-sectional case-control study. Each pair consisted of a case (with impaired cognition) and a control subject matched by age and educational status. Cognitive functions were determined using a modified version of the Blessed test. Participants were also subjected to a general clinical examination and they were interviewed to collect information on lifestyle practices and comorbid disorders. Genotypes for the apolipoprotein E (APOE) epsilon4, catechol-O-methyltransferase (COMT) Val/Met, and brain-derived neurotropic growth factor (BDNF) Val/Met polymorphisms were determined. Data were analyzed by conditional logistic regression.

RESULTS

We identified a set of risk factors for age-related cognitive impairment. A statistical model for assessment of the importance of these factors was constructed. The factors in this model were physical exercise (odds ratio [OR] = 0.50, 95% confidence interval [CI] = 0.32-0.78), regular alcohol consumption (OR = 0.49, 95% CI = 0.29-0.83), metabolic syndrome (OR = 2.83, 95% CI = 1.26-6.39), depression (OR = 3.24, 95% CI = 1.28-8.22), and the APOE epsilon4 allele (OR = 1.76, 95% CI = 1.09-2.83). Also COMT genotype was present as a risk factor in the statistical model (p = 0.08).

CONCLUSIONS

Lifestyle risk factors, comorbid disorders, and genetic factors contribute to development of age-related cognitive impairment. The two former groups of risk factors appear to be particular important in this respect.

The NEO-FFI is a reliable measure of premorbid personality in patients with probable Alzheimer's disease

AIM

To assess the inter-informant reliability, intra-informant reliability and internal consistency of the NEO-FFI as a measure of premorbid personality in patients with Alzheimer's Disease (AD).

SUBJECTS

One hundred and five persons with NINCDS-ADRDA probable AD for the assessment of inter-informant reliability and internal consistency, and 30 for the assessment of intra-informant reliability.

METHODS

Premorbid personality was rated retrospectively by close relatives remembering the patient as he/she had been when aged in his/her forties. One hundred and five AD patients were rated by two separate informants. Thirty AD patients were rated by the same informant on separate occasions one year apart.

RESULTS

Inter-informant reliability for the five domain scores of the NEO-FFI was shown to range from fair to good when measured using the single measure Intraclass Correlation Co-efficient (ICC) (0.52-0.64), and to range from good to excellent when measured using the average ICC (0.68-0.78). Intra-informant reliability for four out of the five domains was shown to be excellent when measured using the single ICC (0.81-0.92), and good for the remaining domain (0.72). Intra-informant reliability was found to be excellent for all five domains when measured using the average ICC (0.84-0.96). Internal consistency of the five domains was good.

CONCLUSIONS

The NEO-FFI can be used reliably to measure premorbid personality in patients with probable AD. It may be useful to maximise reliability by using a mean domain score based on questionnaires completed by two or more informants who knew the patient well earlier in life.

The relation of cigarette smoking to incident Alzheimer's disease in a biracial urban community population

The relationship between smoking status and incident Alzheimer's disease (AD) was investigated in a random stratified sample of a biracial community in Chicago. Analyses are based on 1,064 persons (of 1,134 evaluated) who had data on smoking status, disease incidence, and key covariates such as apolipoprotein allele status. During a mean of about 4 years of follow-up, 170 persons met criteria for incident AD. Current smoking was associated with increased risk of incident AD (OR = 3.4, 95% CI = 1.4-8.0) compared to persons who never smoked. There was no apparent increase in risk of AD for former smokers compared to persons who never smoked (OR = 0.9, 95% CI = 0.5-1.7). Apolipoprotein E allele status modified this association in that former smokers with a upsilon4 allele were less likely to develop AD (p = 0.04) than those who never smoked. Former smokers also appeared to have a reduced risk of developing AD as their pack-years of smoking increased (p = 0.02)such that the odds of developing AD increased by 50% for every 10 years of smoking cessation (OR = 1.3, CI = 0.9-1.7). The results suggest that older people who currently smoke are more likely to develop AD compared to those who never smoked; the relation between those who used to smoke but quit and the risk of AD is complex and requires further research.

The dawn of fungal pathogen genomics

Recent advances in sequencing technologies have led to a remarkable increase in the number of sequenced fungal genomes. Several important plant pathogenic fungi are among those that have been sequenced or are being sequenced. Additional fungal pathogens are likely to be sequenced in the near future. Analysis of the available genomes has provided useful information about genes that may be important for plant infection and colonization. Genome features, such as repetitive sequences, telomeres, conserved syntenic blocks, and expansion of pathogenicity-related genes, are discussed in detail with Magnaporthe oryzae (M. grisea) and Fusarium graminearum as examples. Functional and comparative genomic studies in plant pathogenic fungi, although still in the early stages and limited to a few pathogens, have enormous potential to improve our understanding of the molecular mechanisms involved in host-pathogen interactions. Development of advanced genomics tools and infrastructure is critical for efficient utilization of the vast wealth of available genome sequence information and will form a solid foundation for systems biology studies of plant pathogenic fungi.

Neuroticism, extraversion, and mortality in a defined population of older persons

OBJECTIVE

The objective of this study was to test the association of the personality traits of neuroticism and extraversion with risk of death in old age.

METHODS

A census was taken of a geographically defined urban community in Chicago, and those aged 65 years or older were invited to participate in an in-home interview; 6158 (79% of those eligible) did so. The interview included brief measures of neuroticism and extraversion, medical history, and questions about current participation in cognitive, social, and physical activities. Vital status was subsequently monitored. The association of each trait with risk of death was examined in a series of accelerated failure-time models that controlled for age, sex, race, and education.

RESULTS

During a mean of more than 6 years of observation, 2430 persons (39.5%) died. A high level of neuroticism (score = 27; 90th percentile) was associated with a 33% increase in risk of death compared with a low level of neuroticism (score = 9; 10th percentile). A high level of extraversion (score = 33; 90th percentile) was associated with a 21% decrease in risk of death compared with a low level (score = 18; 10th percentile). Adjustment for medical conditions and health-related variables did not substantially affect results, but adjusting for baseline levels of cognitive, social, and physical activity reduced the association of both traits with mortality.

CONCLUSIONS

The results suggest that higher extraversion and lower neuroticism are associated with reduced risk of mortality in old age and that these associations are mediated in part by personality-related patterns of cognitive, social, and physical activity.

Socioeconomic Characteristics of the Community in Childhood and Cognition in Old Age

We examined the relation of early life socioeconomic circumstances to cognition in older residents of a biracial urban community. Participants had brief cognitive testing three times at approximately 3-year intervals. At baseline, information about early life household and county socioeconomic level was collected. In mixed-effects models adjusted for age, sex, race, and education, both early life household and county socioeconomic levels were positively associated with baseline level of cognition but unrelated to cognitive decline. The results suggest that socioeconomic conditions in early life are associated with level of cognitive function in old age but not with rate of cognitive decline.