Development and validation of risk index for cognitive decline using blood-derived markers

Cognitive Status and Nutritional Markers in a Sample of Institutionalized Elderly People

Background

Since many of the risk factors for cognitive decline can be modified by diet, the study of nutrition and its relationships with cognitive status in aging has increased considerably in recent years. However, there are hardly any studies that have assessed cognitive status using a comprehensive set of neuropsychological tests along with measures of functional capacity and mood and that have related it to nutritional status measured from several nutritional parameters that have shown its relationships with cognitive function.

Objective

To test the differences in depressive symptomatology and in several measures of nutritional status between three groups classified according to their cognitive status (CS hereafter).

Method

One hundred thirteen participants from nursing homes in Galicia, Spain, underwent a comprehensive neuropsychological examination, including a general screening test (MMSE) and tests for different cognitive domains along with measures of activities of daily living (ADL) and assessment of depressive symptomatology (GDS-SF). According to established clinical criteria, participants were divided into three CS groups, Cognitively Intact (CI), Mild Cognitive Impairment (MCI), and All-Cause Dementia (ACD). Nutritional status was also examined using blood-derived measures, body mass index (BMI) and a nutritional screening test (MNA-SF). Differences between CS groups in all nutritional variables were studied by one-way ANOVAs with post-hoc Bonferroni correction or Kruskal-Wallis with Games-Howell post-hoc correction when appropriate. Multinomial logistic regression was also applied to test the association between nutritional variables and CS.

Results

Differences between CS groups were statistically significant for depressive symptomatology, vitamin A and D, albumin, selenium (Se), uric acid (UA), and BMI. The results of multinomial logistic regression found positive associations between groups with better CS and higher concentrations of vitamins A and D, transthyretin (TTR), albumin, Se, and UA, while negative associations were found for BMI.

Conclusion

Higher serum levels of vitamin A, vitamin D, TTR, albumin, Se, and UA could act as protective factors against cognitive decline, whereas higher BMI could act as a risk factor.

Distinguishing Alzheimer's Disease Patients and Biochemical Phenotype Analysis Using a Novel Serum Profiling Platform: Potential Involvement of the VWF/ADAMTS13 Axis

It is important to develop minimally invasive biomarker platforms to help in the identification and monitoring of patients with Alzheimer's disease (AD). Assisting in the understanding of biochemical mechanisms as well as identifying potential novel biomarkers and therapeutic targets would be an added benefit of such platforms. This study utilizes a simplified and novel serum profiling platform, using mass spectrometry (MS), to help distinguish AD patient groups (mild and moderate) and controls, as well as to aid in understanding of biochemical phenotypes and possible disease development. A comparison of discriminating sera mass peaks between AD patients and control individuals was performed using leave one [serum sample] out cross validation (LOOCV) combined with a novel peak classification valuation (PCV) procedure. LOOCV/PCV was able to distinguish significant sera mass peak differences between a group of mild AD patients and control individuals with a p value of 10^-13. This value became non-significant (p = 0.09) when the same sera samples were randomly allocated between the two groups and reanalyzed by LOOCV/PCV. This is indicative of physiological group differences in the original true-pathology binary group comparison. Similarities and differences between AD patients and traumatic brain injury (TBI) patients were also discernable using this novel LOOCV/PCV platform. MS/MS peptide analysis was performed on serum mass peaks comparing mild AD patients with control individuals. Bioinformatics analysis suggested that cell pathways/biochemical phenotypes affected in AD include those involving neuronal cell death, vasculature, neurogenesis, and AD/dementia/amyloidosis. Inflammation, autoimmunity, autophagy, and blood-brain barrier pathways also appear to be relevant to AD. An impaired VWF/ADAMTS13 vasculature axis with connections to F8 (factor VIII) and LRP1 and NOTCH1 was indicated and is proposed to be important in AD development.

Adaptation of the Modified Mini-Mental State Examination (3MS) and Determination of Its Normative Values in Turkey

BACKGROUND/AIMS

This study aimed to adapt the Modified Mini-Mental State Examination (3MS) and determine its normative values in Turkey.

METHODS

After translation and cultural adaptation processes, a population-based study was conducted between February and June 2016 in Ankara with individuals over the age of 55 years. Subjects with a previous diagnosis of dementia along with neuropsychiatric disorders that might affect cognition were excluded. Data analyses were performed to assess the association of sociodemographic variables with 3MS scores.

RESULTS

Two versions of the Turkish 3MS (for educated and minimally educated individuals) were developed. A total of 2,235 participants were included in the field study. After exclusion, the data on the final sample of 1,909 individuals were analyzed, where age, gender, and education accounted for variance in 3MS scores. Younger age and higher educational attainment were associated with better 3MS performance.

CONCLUSIONS

A widely applicable dementia screening test was adapted to Turkish and its normative values were determined. The test will make it possible to evaluate the cognitive performance of both educated and minimally educated elderly individuals based on their age, gender, and educational level.

Biological Age, Not Chronological Age, Is Associated with Late-Life Depression

Background

The pathophysiology of late-life depression (LLD) is complex and heterogeneous, with age-related processes implicated in its pathogenesis. This study examined the cross-sectional and longitudinal association between depressive symptoms and a baseline multibiomarker algorithm of biological age (BA) that aggregates indicators of inflammatory, metabolic, cardiovascular, lung, liver, and kidney functioning.

Method

Data were analyzed from 2,776 men and women from the prospective observational Health Aging and Body Composition Study, who had both evaluable chronological age (CA) and BA. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression (CES-D) scale.

Results

A covariate-adjusted regression model showed that BA (B = 0.03, p = .0471) but not CA (B = -0.01, p = .7185) is associated with baseline CES-D scores. The mean baseline BA for individuals with a CES-D ≥ 10 was 1.28 years greater than in those with a CES-D < 10. Comparatively, there is only a 0.05-year difference in mean CA between the two depression groups. A covariate-adjusted longitudinal model found that baseline BA predicts CES-D score at follow-up (B = 0.04, p = .0058), whereas CA does not (B = 0.03, p = .4125). Additionally, an older BA significantly predicted a CES-D ≥ 10 (B = 0.02, p = .032) over a 10-year period.

Conclusions

A multibiomarker index of an older adult's BA outperformed their CA in predicting subsequent increased and clinically significant depressive symptoms. This result supports the evolving view of LLD as a brain disorder resulting from deleterious age-associated changes across numerous physiological systems.

Defining the Optimal Target Population for Trials of Polyunsaturated Fatty Acid Supplementation Using the Erythrocyte Omega-3 Index: A Step Towards Personalized Prevention of Cognitive Decline?

OBJECTIVES

to identify the optimal erythrocyte omega-3 index cut-off for predicting cognitive decline and/or polyunsaturated fatty acid (PUFA) treatment response, in order to better define the target population for future dementia prevention trials.

DESIGN AND SETTING

Secondary exploratory analysis of the randomized controlled MAPT prevention trial.

PARTICIPANTS

724 dementia-free subjects aged 70 or older with subjective memory complaints, limitations in one instrumental activity of daily living, and/or slow gait speed.

INTERVENTION

800mg docosahexaenoic acid (DHA) and 225mg eicosapentaenoic acid (EPA) daily versus placebo.

MEASUREMENTS

Erythrocyte omega-3 index was measured at baseline. Cognition was measured over 3 years with a composite cognitive score (mean of 4 z-scores).

RESULTS

Placebo group subjects in the lowest quartile of baseline erythrocyte omega-3 index (i.e. ≤4.83%) underwent significantly more 3-year cognitive decline than the other quartiles (mean composite score difference 0.14, 95%CI [0.00, 0.28], p=0.048). In a ROC curve analysis, the optimal omega-3 index cut-off for predicting notable cognitive decline was 5.3%. There was a consistent but non-significant difference in 3-year cognitive decline of approximately 0.12 points between PUFA-treated and placebo subjects with "low" baseline omega-3 index when the cut-off was set at ≤5.27%.

CONCLUSIONS

Dementia-free older adults with an omega-3 index below approximately 5% are at increased risk of cognitive decline, and could be a good target population for testing the cognitive effects of PUFA supplementation.

Comparison of Associations of DXA and CT Visceral Adipose Tissue Measures With Insulin Resistance, Lipid Levels, and Inflammatory Markers

Visceral adipose tissue (VAT) measured by computed tomography (CT) is related to insulin resistance, lipids, and serum inflammatory markers. Our objective was to compare the strength of the associations of VAT measured using dual-energy X-ray absorptiometry (DXA-VAT) and CT (CT-VAT) with insulin resistance, serum lipids, and serum markers of inflammation. For 1117 men aged 65 and older enrolled in the Osteoporotic Fractures in Men Study, the cross-sectional associations of DXA-VAT and CT-VAT with homeostasis model assessment of insulin resistance (homa2ir), C-reactive protein, and high-density lipoprotein (HDL) cholesterol were estimated with regression models and compared using a Hausman test. Adjusted for age and body mass index, DXA-VAT was moderately associated with homa2ir (effect size 0.38, 95% confidence interval [CI]: 0.28-0.47) and modestly associated with HDL cholesterol (DXA effect size -0.29, 95% CI: -0.38 to -0.21). These associations were significantly greater than those for CT-VAT with homa2ir (0.30, 95% CI: 0.24-0.37; p value for effect size difference 0.03) and CT-VAT with HDL cholesterol (-0.22, 95% CI: -0.29 to -0.15; p value for difference 0.005). Neither DXA-VAT nor CT-VAT was associated with C-reactive protein after adjustment for age and body mass index (DXA-VAT effect size 0.14, 95% CI: -0.04 to 0.32; CT-VAT effect size 0.08, 95% CI: -0.08 to 0.25; p value for difference 0.35). DXA-VAT has similar or greater associations with insulin resistance and HDL cholesterol as does CT-VAT in older men, confirming the concurrent validity of DXA-VAT. Investigations of how well DXA measurements of VAT predict incident cardiovascular disease events are warranted.

Association of Plasma β-Amyloid with Cognitive Performance and Decline in Chronic Kidney Disease

Decreased β-amyloid (Aβ) clearance from the brain has been suggested to contribute to cerebral Aβ accumulation in Alzheimer's disease. Based on the idea of a dynamic Aβ equilibrium in different body compartments, plasma Aβ levels have been investigated as biomarker candidates for preclinical Alzheimer's pathology, yet with inconsistent results. Since the kidneys are involved in Aβ elimination from the blood, we evaluated how chronic kidney disease (CKD) affects the association between plasma Aβ and cognitive deficits and cognitive decline. In 28 CKD patients, stages 3-5D, and 26 control subjects with comparable vascular risk profile from the New Tools for the Prevention of Cardiovascular Disease in Chronic Kidney Disease (NT^CVD) cohort, plasma total Aβ was determined with a highly sensitive electrochemiluminescence immunoassay. Cognition was evaluated using a comprehensive battery of ten neuropsychological tests at baseline and 2-year follow-up. Subjects with high plasma Aβ level (above median) demonstrated a significantly worse baseline cognitive performance than subjects exhibiting low Aβ level (summary score of global cognitive performance at baseline z = -0.46 ± 0.76 vs z = -0.08 ± 0.57, p = 0.045). Cognitive performance moderately decreased over the 2-year follow-up in subjects with high plasma Aβ level (Δz = -0.13 ± 0.51), but increased in subjects with low plasma Aβ level (Δz = 0.16 ± 0.41, p = 0.023). In linear regression analyses, baseline plasma Aβ was significantly associated with cognitive decline both in unadjusted analyses (β = -0.28, 95% CI = -0.55 to -0.01) and analyses adjusted for age (β = -0.27, 95% CI = -0.54 to -0.01). Our results suggest the utility of plasma Aβ level in predicting cognitive decline in patients suffering from CKD.

Blood-Based Oxidative Stress Markers and Cognitive Performance in Early Old Age: The HAPIEE Study

BACKGROUND/AIMS

Oxidative stress is involved in Alzheimer disease pathology, but its impact on cognitive function in community-dwelling older adults remains unknown. We estimated associations between serum oxidative stress markers and cognitive function in early old age.

METHODS

Subjects aged 45-69 years recruited in urban centers in Central and Eastern Europe had memory, verbal fluency, and processing speed assessed at baseline (2002-2005) and 3 years later. Derivatives of reactive oxygen metabolites (d-ROMs), biological antioxidant potential (BAP), and total thiol levels (TTLs) were measured at baseline in a subsample. Linear regression was used to estimate associations of biomarkers with cognitive test scores cross-sectionally (n = 4,304) and prospectively (n = 2,882).

RESULTS

Increased d-ROM levels were inversely associated with global cognition and verbal fluency cross-sectionally and in prospective analysis; observed effects corresponded to 3-4 years' higher age. TTL was inconsistently associated with memory. BAP was not related to cognitive function.

CONCLUSION

This study found modest evidence for a relationship between serum d-ROMs and cognitive function in a population sample of older adults.

Potential fluid biomarkers for pathological brain changes in Alzheimer's disease: Implication for the screening of cognitive frailty

Cognitive frailty (CF) overlaps with early neuropathological alterations associated with aging-related major neurocognitive disorders, including Alzheimer's disease (AD). Fluid biomarkers for these pathological brain alterations allow for early diagnosis in the preclinical stages of AD, and for objective prognostic assessments in clinical intervention trials. These biomarkers may also be helpful in the screening of CF. The present study reviewed the literature and identified systematic reviews of cohort studies and other authoritative reports. The selection criteria for potentially suitable fluid biomarkers included: i) Frequent use in studies of fluid-derived markers and ii) evidence of novel measurement techniques for fluid-derived markers. The present study focused on studies that assessed these biomarkers in AD, mild cognitive impairment and non-AD demented subjects. At present, widely used fluid biomarkers include cerebrospinal fluid (CSF), total tau, phosphorylated tau and amyloid-β levels. With the development of novel measurement techniques and improvements in understanding regarding the mechanisms underlying aging-related major neurocognitive disorders, numerous novel biomarkers associated with various aspects of AD neuropathology are being explored. These include specific measurements of Aβ oligomer or monomer forms, tau proteins in the peripheral plasma and CSF, and novel markers of synaptic dysfunction, neuronal damage and apoptosis, neuronal activity alteration, neuroinflammation, blood brain barrier dysfunction, oxidative stress, metabolites, mitochondrial function and aberrant lipid metabolism. The proposed panels of fluid biomarkers may be useful in the early diagnosis of AD, prediction of the progression of AD from preclinical stages to the dementia stage, and the differentiation of AD from non-AD dementia. In combination with physical frailty, the present study surmised that these biomarkers may also be used as biomarkers for CF, thus contribute to discovering causes and informing interventions for cognitive impairment in individuals with CF.

The Alzheimer's Prevention Clinic at Weill Cornell Medical College / New York - Presbyterian Hospital: Risk Stratification and Personalized Early Intervention

In July 2013, Weill Cornell Medical College founded the first Alzheimer's Prevention Clinic (APC) in the United States, providing direct clinical care to family members of patients with Alzheimer's disease (AD) as part of the Weill Cornell Memory Disorders Program. At the APC, patients seeking to lower their AD risk undergo a comprehensive assessment, receive a personalized plan based on rapidly evolving scientific evidence, and are followed over time using validated as well as emerging clinical and research technologies. The APC approach applies the principles of pharmacogenomics, nutrigenomics and clinical precision medicine, to tailor individualized therapies for patients. Longitudinal measures currently assessed in the clinic include anthropometrics, cognition, blood biomarkers (i.e., lipid, inflammatory, metabolic, nutritional) and genetics, as well as validated, self-reported measures that enable patients to track several aspects of health-related quality of life. Patients are educated on the fundamental concepts of AD prevention via an interactive online course hosted on Alzheimer's Universe (www.AlzU.org), which also contains several activities including validated computer-based cognitive testing. The primary goal of the APC is to employ preventative measures that lower modifiable AD risk, possibly leading to a delay in onset of future symptoms. Our secondary goal is to establish a cohort of at-risk individuals who will be primed to participate in future AD prevention trials as disease-modifying agents emerge for testing at earlier stages of the AD process. The clinical services are intended to lower concern for future disease by giving patients a greater sense of control over their brain health.