Neuropsychiatric Symptoms are Related to Blood-biomarkers in Major Neurocognitive Disorders

BACKGROUND

Neuropsychiatric symptoms (NPS) are highly prevalent among individuals with major neurocognitive disorders (MNCD).

OBJECTIVE

Here, we characterized blood biomarkers (metabolic, inflammatory, neurotrophic profiles and total antioxidant), body composition, physical fitness and quality of life (QoL) in individuals with MNCD according to NPS.

METHODS

The sample comprised 34 older adults (71.4% women; 74.06±6.03 yrs, with MNCD diagnosis) categorized according to 50th percentile [Low (≤12) or High (≥13)] for NPS (Neuropsychiatric Inventory Questionnaire). Sociodemographic, clinical data, body composition, anthropometric, cognitive assessment (ADAS-Cog), physical fitness (Senior Fitness Test), QoL (QoL-Alzheimer's Disease scale) were evaluated, and blood samples were collected for biochemical analysis.

RESULTS

Low compared to high NPS group showed higher levels of IL-6, IGF-1and neurotrophic zscore (composite of IGF-1, VEGF-1, BDNF). Additionally, low compared to high NPS group have higher QoL, aerobic fitness and upper body and lower body strength.

CONCLUSION

The severity of NPS seems to be related to modified neurotrophic and inflammatory outcomes, lower physical fitness, and poor QoL. Strategies to counteract NPS development may preserve the physical and mental health of individuals with MNCD.

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Low-grade inflammation differentiates between symptoms of apathy and depression in community-dwelling older individuals

BACKGROUND

Systemic low-grade inflammation has repeatedly been associated with depression in old age, but the relationship with apathy is less clear. The present study assessed whether C-reactive protein (CRP) is differentially associated with symptoms of apathy and depression.

METHODS

A population-based cohort study was carried-out. At baseline and after two and four years of follow-up, CRP levels were assessed and symptoms of apathy and depression were measured using the 15-item Geriatric Depression Scale. Logistic regression analysis was used to investigate the cross-sectional and longitudinal associations of CRP with symptoms of apathy and depression.

RESULTS

Two thousand forty-seven community-dwelling participants (70-78 years) without a history of cardiovascular disease or stroke were studied. A cross-sectional association was found between CRP and apathy symptoms at three time points (odds ratio (OR) per natural log unit increase in CRP: baseline visit = 1.40, 95% CI = 1.12-1.75; two-year follow-up visit = 1.62, 95% CI = 1.17-2.25; four-year follow-up visit = 1.51, 95% CI = 1.03-2.21). This did not change after adjustment for demographics and depressive symptoms, and was slightly attenuated after adjustment for cardiovascular risk factors. No cross-sectional association was found with depressive symptoms. Baseline CRP did not predict incident apathy or depressive symptoms during four years of follow-up.

CONCLUSIONS

Increased CRP levels are associated with apathy symptoms but not with depressive symptoms. This suggests a differential effect of inflammation on apathy and depression. In older persons, symptoms of apathy may be a behavioral manifestation of concurrent low-grade inflammation.

Serum levels of soluble TNF-α receptors but not BDNF are associated with apathy symptoms in mild Alzheimer's disease and amnestic mild cognitive impairment

Apathy is intimately associated with dementia. Unfortunately, its pathophysiology remains poorly understood. The motivational impairment that characterizes this disorder might share the same inflammatory mechanisms, as suggested by the sickness behavior theory.

OBJECTIVE

The primary aim of this study was to investigate the association between apathy symptoms and serum levels of tumor necrosis factor alpha (TNF-α) and its soluble receptors. Brain-derived neurotrophic factor (BDNF) levels were also analyzed since these have been associated with depression, a condition which shares abulic features with apathy.

METHODS

The sample consisted of 27 subjects with mild Alzheimer's disease or amnestic mild cognitive impairment, who were submitted to specific apathy evaluation using the Apathy Scale (AS) and provided blood samples for biomarker analysis. Participants were categorized into two groups according to median AS scores (17 points).

RESULTS

Subjects with higher apathy symptoms (n=13) displayed higher levels of TNF-α soluble receptors (type 1: p=0.03; type 2: p=0.04). No other difference was found between groups.

CONCLUSION

These findings point to the involvement of inflammatory mediators in the genesis of apathy symptoms, as suggested by the sickness behavior theory.