Relationship between baseline plasma p-tau181 and longitudinal changes in cognition and structural brain measures in a cohort of cognitively unimpaired older adults.

INTRODUCTION: Preclinical Alzheimer's disease (AD) affects a significant proportion of cognitively unimpaired (CU) older adults. Currently, blood-based biomarkers detect very early changes in the AD continuum with great accuracy. METHODS: We measured baseline plasma phosphorylated tau (p-tau)181 using electrochemiluminescence (ECL)-based assay (MesoScale Discovery) in 533 CU older adults. Follow-up lasted up to 18 months. Cognitive performance assessment included memory and cognitive control. Structural brain measures included cortical thickness, which includes the AD magnetic resonance imaging (AD MRI) signature, and hippocampal volume. RESULTS: In this cohort of CU older adults, baseline plasma p-tau181 levels were not associated with short-term changes in cognition and structural brain measures. Also, baseline plasma p-tau levels did not influence the effects of behavioral interventions (exercise or mindfulness) on cognitive and structural brain changes. DISCUSSION: The short follow-up and healthy status of this CU cohort might have limited the sensitivity of plasma p-tau181 in detecting changes associated with AD pathology.

Plasma Biomarkers of Alzheimer's Disease: A Review of Available Assays, Recent Developments, and Implications for Clinical Practice.

Recently, low-sensitive plasma assays have been replaced by new ultra-sensitive assays such as single molecule enzyme-linked immunosorbent assay (Simoa), the Mesoscale Discovery (MSD) platform, and immunoprecipitation-mass spectrometry (IP-MS) with higher accuracy in the determination of plasma biomarkers of Alzheimer's disease (AD). Despite the significant variability, many studies have established in-house cut-off values for the most promising available biomarkers. We first reviewed the most used laboratory methods and assays to measure plasma AD biomarkers. Next, we review studies focused on the diagnostic performance of these biomarkers to identify AD cases, predict cognitive decline in pre-clinical AD cases, and differentiate AD cases from other dementia. We summarized data from studies published until January 2023. A combination of plasma Aß42/40 ratio, age, and APOE status showed the best accuracy in diagnosing brain amyloidosis with a liquid chromatography-mass spectrometry (LC-MS) assay. Plasma p-tau217 has shown the best accuracy in distinguishing Aß-PET+ from Aß-PET-even in cognitively unimpaired individuals. We also summarized the different cut-off values for each biomarker when available. Recently developed assays for plasma biomarkers have undeniable importance in AD research, with improved analytical and diagnostic performance. Some biomarkers have been extensively used in clinical trials and are now clinically available. Nonetheless, several challenges remain to their widespread use in clinical practice.

Neuropsychiatric symptoms and cerebrovascular risk in non-demented elders: cross-sectional study using the mild behavioural impairment checklist (MBI-C).

BACKGROUND: Neuropsychiatric symptoms (NPS) may represent early clinical manifestations of evolving brain diseases. Studies underpin the occurrence of NPS in the context of mild cognitive impairment (MCI) and prodromal Alzheimer's disease, where symptoms referred to as 'mild behavioural impairment' (MBI) have been shown to predict conversion to dementia and to hasten cognitive/functional decline. However, the association between NPS and cerebrovascular risk factors has been poorly investigated, despite the high prevalence of the latter among individuals with MCI. The aim of the present study was to investigate the association between MBI and cerebrovascular risk in a clinical sample of non-demented elders. METHODS: Sixty-five MCI and 15 cognitively unimpaired older adults were cross-sectionally assessed with the Mild Behavioural Impairment Checklist (MBI-C), using the cut-off score > 6.5 to define positive screening. Participants were submitted to the Hachinski Ischaemic Score (HIS) to account for cerebrovascular symptoms, vascular risk, and related comorbidities. Neuroimaging scans (magnetic resonance imaging and/or 18F-fluorodeoxyglucose-positron emission tomography) and apolipoprotein E genotype were obtained. RESULTS: Positive associations were found between total MBI-C scores and increasing number of comorbidities present (0-2 comorbidities), but not with three comorbidities. Two domains of the MBI-C-impulse dyscontrol and social inappropriateness-followed the same trend of the MBI-C total score, with higher scores with the increasing numbers of comorbidities. No significant associations were found between MBI symptoms and HIS or cerebrovascular burden in neuroimaging assessment. CONCLUSION: We found weak associations between MBI-C total score and the presence of comorbidities with cerebrovascular risk, but not with structural or functional neuroimaging abnormalities or HIS. This finding may represent that the presence of comorbidities adds limited risk to the occurrence of MBI in this sample of non-demented elders.

AD-Related CSF Biomarkers Across Distinct Levels of Cognitive Impairment: Correlations With Global Cognitive State.

AIM: Associations between cerebrospinal fluid (CSF) biomarkers of Alzheimer's disease (AD) with the severity of cognitive impairment are unclear. We examined the correlations between CSF biomarkers and cognitive performance in the AD continuum. METHODS: We studied 143 elderly patients: cognitively unimpaired (n = 51), mild cognitive impairment (MCI) amnestic (n = 55) and nonamnestic (n = 20), and mild AD (n = 17) assessed with the Cambridge Cognitive Test (CAMCOG). We correlated total CAMCOG and its subdomains with CSF Aß42, T-tau, p-tau levels, and Aß42/p-tau. RESULTS: In the total sample, T-tau and Aß42/p-tau correlated with the total CAMCOG (P < .01); all biomarkers correlated with memory (P < .001); T-tau correlated with language (P < .01). CONCLUSION: Memory and T-tau levels may be the most suitable parameters to reflect cognitive/CSF biomarker correlations. At present, such correlations are of little use in routine clinical practice.

Mental Health Status of Psychogeriatric Patients During the 2019 New Coronavirus Disease (COVID-19) Pandemic and Effects on Caregiver Burden.

Introduction: There is a growing awareness about the noxious effects of the 2019 Coronavirus Disease (COVID-19) pandemic on the mental health of the elderly. However, there is limited information from clinically driven research. The objectives of the present study were to examine the magnitude of psychiatric symptoms and to determine their association with caregiver distress, in a cross-section of community-dwelling older adults and a subsample of aging adults with Down syndrome (DS) attending a psychogeriatric service in São Paulo, Brazil. Method: Telephone-based interviews and electronically filled self-assessment questionnaires were used to collect information from patients and caregivers, addressing their impressions and concerns about the pandemic and related effects on the patient's emotional state and behavior. Clinical information was obtained from hospital charts, medical records, and psychometric tests administered through telephone interviews [Hospital Anxiety and Depression Scale (HADS) and Neuropsychiatric Inventory Questionnaire (NPI-Q)]. Results: We included 100 consecutive participants, comprising 71 older adults with psychogeriatric/neurocognitive disorders and 29 aging adults with DS. Higher HADS and NPI-Q scores were significantly associated with caregiver distress (p < 0.05) in both groups. Correlation analyses indicated strong, positive associations between caregiver burden and scores in HADS anxiety (HADS-A) and HADS depression (HADS-D) scales in the subsamples of euploid and DS subjects. Higher NPI-Q scores in the former group were also correlated with caregiver distress, with stronger associations for neuropsychiatric symptoms. Similar findings were observed among DS subjects. ANOVA tests indicated significant associations between NPI-Q scores and caregiver distress among dementia patients, as well as with HADS scores. Similar results were found after multiple linear regressions; as such, among the elderly subsample, higher scores in HADS-A (p = 0.002) and HADS-D (p = 0.001) predict a significant impact on caregiver burden (p < 0.00001, R 2 0.46); taking into consideration caregiver burden as a dependent variable and NPI-Q total score as an independent variable, we obtained significant strong prediction values for either DS (p < 0.00001, R 2 0.95) or elderly adults (p < 0.00001, R 2 0.88). Conclusion: During the COVID-19 pandemic, patients with neurocognitive disorders present with clinically relevant neuropsychiatric symptoms, with significant impact on caregiver distress. Apathy, aberrant motor behavior, sleep disorders, and psychoses were the main psychopathological domains, which had determined caregiver burden worsening.

Cognitive impairment in remitted late-life depression is not associated with Alzheimer's disease-related CSF biomarkers.

BACKGROUND: Cognitive impairment is a common feature of late-life depression (LLD). Early studies using Alzheimer's disease (AD) biomarkers inferred a biological link between AD pathology and LLD, but recent findings have challenged this association. The aim of this investigation was to determine a panel of AD-related cerebrospinal fluid (CSF) biomarkers in a cross-section of elders with mild cognitive impairment (MCI) with and without LLD. METHODS: Subjects comprised 102 older adults: 27 with 'pure' amnestic MCI (aMCI), 53 with major depression and cognitive impairment - encompassing 22 late-onset (LOD) and 31 early-onset depression (EOD), and 22 euthymic elders without cognitive impairment (controls). Participants underwent lumbar puncture for determination of CSF concentrations of Aß1-42, T-tau, and P-tau. Cut-off scores for suspected AD were: Aß1-42 < 416p g/mL, P-tau > 36.1 pg/mL and Aß/P-tau ratio < 9.53 (O. V. Forlenza et al. 2015). Statistical analyses consisted of analyses of variance (ANOVA), analyses of covariance (ANCOVA), Bonferroni post-hoc tests, and Pearson's chi-squared tests. RESULTS: ANCOVA (age and schooling as covariates) displayed statistically significant results with respect to CSF biomarkers' profiles regardless of the socio-demographic divergencies previously identified by one-way ANOVA. Mean Aß1-42 values (pg/mL) were: aMCI, 360.3 (p < 0.001); LOD, 486.6 (p < 0.001); EOD, 494.2 (p < 0.001); controls, 528.3 (p < 0.001); p< 0.05. Mean Aß1-42/P-tau ratio: aMCI, 7.9 (p < 0.001); LOD 14.2 (p < 0.001); EOD, 15.3 (p < 0.001); controls, 17.1 (p < 0.001); p < 0.05. Post-hoc tests indicated that patients with aMCI showed significant differences in biomarker profile compatible with AD signature. LIMITATION: The main limitation is the relatively small sample. CONCLUSION: Our findings suggest that, distinctively from aMCI, cognitive impairment in LLD is not associated with AD's CSF pathological signature.

Passive antiamyloid immunotherapy for Alzheimer's disease.

PURPOSE OF REVIEW: Antiamyloid therapy of Alzheimer's disease tackles the overproduction and clearance of the amyloid-beta peptide (Aß). Immunotherapeutic compounds were tested in large-scale trials. We revisit the recent literature focusing on randomized-controlled trials (RCT) using monoclonal anti-Aß antibodies. RECENT FINDINGS: Forty-three articles on anti-Aß passive immunotherapy for Alzheimer's disease were published between January 2016 and October 2019 regarding 17 RCTs: 13 phase III trials using the monoclonal antibodies bapineuzumab, solanezumab, gantenerumab, crenezumab, and aducanumab; three phase II with crenezumab and aducanumab; and one phase I trial with BAN2401. Studies resulted largely negative considering the effect of the treatment on primary and secondary outcome variables. The incidence of the most important adverse effect, amyloid-related imaging abnormalities (ARIAs) ranged between 0.2 and 22%, in treatment groups. Primary endpoints were not met in eight trials, and five trials were discontinued prior to completion. SUMMARY: Passive immunotherapy RCTs failed to show clinically relevant effects in patients with clinically manifest or prodromal dementia. The high incidence of ARIAs indicates that the risk of adverse events may outweigh the benefits of these interventions. Ongoing studies must determine the benefit of such interventions in preclinical Alzheimer's disease, addressing the effect of antiamyloid immunotherapy in samples of asymptomatic carriers of autosomal-dominant mutations related to early-onset Alzheimer's disease.

Safety Limits of Antidepressant Use Plus Combinations: Focus on Cardiovascular Function.

BACKGROUND: Antidepressants have been widely prescribed for depression, anxiety, sleep disorders, and in the management of behavioural symptoms of adult-old patients. Although generally safe, newer generation antidepressants are not devoid of the risk of inducing clinically relevant adverse events. OBJECTIVES: To investigate the association between newer generation antidepressants and the occurrence of cardiovascular adverse events and electrocardiogram (ECG) abnormalities. METHOD: Studies were included in the review according to the following criteria: a) clinical trials (placebo-controlled or not) or case reports; b) short- or long-term interventions with antidepressants; c) prescription of newer generation antidepressants as first-line treatment; d) samples of adult or adult-old patients. From a total of 301 articles addressing the association between antidepressants and cardiovascular adverse events as primary or secondary outcomes, we selected 30 controlled clinical trials and 10 case reports. RESULTS: In most clinical studies, the effects of antidepressants on cardiac function are usually computed as secondary outcome variables, however with limited information. Conversely, case reports tend to present more comprehensive sets of clinical and laboratorial parameters, but the generalization of such data is limited by the small number of observations. The occurrence of QTc prolongation (with increased risk of torsade de pointes) has been reported. Aging, higher dosages of antidepressants, drug interaction, and pre-existing cardiovascular comorbidities were found as risk factors for the aforementioned cardiovascular and ECG abnormalities. CONCLUSION: Prescribing antidepressants requires caution given their potential impact on cardiac function, and the clinician should carefully monitor cardiovascular and ECG parameters particularly in cases with underlying heart disease.