The association of late-life depressive symptoms with brain amyloid-β deposition: the ARIC-PET study

Background and Purpose- Cardiovascular disease is a known risk factor for cognitive decline, although the mechanisms remain unclear. We hypothesize that Aβ (β-amyloid), a core pathology of Alzheimer's disease, will be associated with subclinical cardiac structure and function echocardiogram indices. Methods- Three hundred six nondemented participants from the ARIC study (Atherosclerosis Risk in Communities Study) underwent florbetapir positron emission tomography and 2D echocardiography (echo). Cross-sectional associations between echo markers of left ventricular structure and function and global cortical Aβ (≥1.2 standardized uptake value ratio were evaluated using multivariable logistic regression with interaction terms when appropriate. Results- Participants ranged in age from 67 to 88 years, were 57% female and 42% black. Per 1 cm increase in end-diastolic left ventricular diameter, the odds of elevated florbetapir standardized uptake value ratio doubled (odds ratio, 2.04 [95% CI, 1.10-3.77]), with similar findings when excluding mild cognitive impairment (odds ratio, 2.61 [95% CI, 1.22-5.59]). Conclusions- We have demonstrated a significant association between a marker of left ventricular structure and elevated florbetapir standardized uptake value ratio, identified using positron emission tomography. Ongoing prospective work will help determine if changes in cardiac structure and function either precede, or occur simultaneously with deposition of amyloid.

Background: Atrial fibrillation (AF) is a risk factor for cognitive decline, perhaps due to silent cerebral infarction, but it is unknown if it also acts on Alzheimer’s Disease (AD)-specific mechanisms, such as deposition of β-amyloid (Aβ). Left atrial changes in structure or function, or atrial cardiopathy, can lead to AF but may cause infarcts independently, and thus might also impact cognition. We hypothesize that Aβ is associated with AF and atrial cardiopathy, independent of AF, when defined similarly to an ongoing clinical trial (ARCADIA). Methods: 321 participants without dementia from the Atherosclerosis Risk in Communities study underwent florbetapir (FBP) PET, electrocardiogram and 2D echocardiography. Atrial cardiopathy was defined as ≥1 of: 1) left atrial volume index (LAVI) >34 ml/m2; 2) P-wave terminal force >5000 uV x ms and 3) serum NT proBNP>250 pg/mL. Cross-sectional associations between global cortical Aβ (>1.2 standardized uptake value ratio (SUVR)) and adjudicated history of atrial fibrillation and atrial cardiopathy, each, were evaluated using multivariable logistic regression. Results: Participants, with mean age 76 y, were 56% female and 42% black. Odds of elevated FBP SUVR was increased for those with atrial cardiopathy (Model 3) and nearly doubled among those with enlarged LAVI that remained significant after sequential adjustment, including AF (Table). There was no significant association between either P-wave terminal force or NT proBNP and elevated FBP SUVR (Table), nor between elevated SUVR and AF. Conclusions: In this cross-sectional analysis of a cohort of healthy, nondemented community-dwelling older individuals, we report a significant association between atrial cardiopathy as well as LAVI and elevated amyloid, by PET, without a similar association in individuals with AF. Potential limitations include reverse causation and survival bias. Ongoing work will help determine if changes in cardiac structure and function precede, or occur simultaneously with amyloid deposition.

In this article, we describe an image analysis strategy with improved power for tracking longitudinal amyloid-β (Aβ) PET changes and evaluating Aβ-modifying treatments. Our aims were to compare the power of template-based cerebellar, pontine, and cerebral white matter reference regions to track 24-mo florbetapir standardized uptake value (SUV) ratio (SUVR) changes; to relate those changes to 24-mo clinical declines; and to evaluate Aβ-modifying treatments in Aβ-positive (Aβ+) and Aβ-negative (Aβ-) patients with probable Alzheimer dementia (pAD), in patients with mild cognitive impairment (MCI), in cognitively normal controls (NCs), and in cognitively normal apolipoprotein E4 (APOE4) carriers and noncarriers. We used baseline and follow-up (∼24 mo) florbetapir PET scans from 332 Aβ+ and Aβ- subjects participating in the multicenter Alzheimer's Disease Neuroimaging Initiative. Each of the proposed analyses included 31 pAD patients, 187 MCI patients, and 114 NCs. Cerebral-to-white matter, cerebellar, and pontine SUVRs were characterized in terms of their longitudinal variability; their power to track longitudinal fibrillar Aβ increases in Aβ+ and Aβ- subgroups and cognitively normal APOE4 carriers and noncarriers; the sample sizes needed to detect attenuated accumulation of or clearance of fibrillar Aβ accumulation in randomized clinical trials; and their ability to relate 24-mo fibrillar Aβ increases to clinical declines. As predicted, cerebral-to-white matter SUVR changes were significantly less variable and had significantly greater power to detect 24-mo fibrillar Aβ increases and evaluate Aβ-modifying treatment effects in Aβ+ pAD, MCI, and NC subjects and cognitively normal APOE4 carriers. They were also distinguished by the ability to detect significant associations between 24-mo Aβ increases and clinical declines. A cerebral white matter reference region may improve the power to track longitudinal fibrillar Aβ increases, to characterize their relationship to longitudinal clinical declines, and to evaluate Aβ-modifying treatments in randomized clinical trials.

BackgroundAtrial fibrillation (AF) is a risk factor for cognitive decline, possibly from silent brain infarction. Left atrial changes in structure or function (atrial cardiopathy) can lead to AF but may impact cognition independently. It is unknown if AF or atrial cardiopathy also acts on Alzheimer disease–specific mechanisms, such as deposition of β‐amyloid.Methods and ResultsA total of 316 dementia‐free participants from the ARIC (Atherosclerosis Risk in Communities) study underwent florbetapir positron emission tomography, electrocardiography, and 2‐dimensional echocardiography. Atrial cardiopathy was defined as ≥1: (1) left atrial volume index >34 mL/m2; (2) P‐wave terminal force >5000 µV×ms; and (3) serum NT‐proBNP (N‐terminal pro‐B‐type natriuretic peptide) >250 pg/mL. Cross‐sectional associations between global cortical β‐amyloid (>1.2 standardized uptake value ratio) and adjudicated history of AF and atrial cardiopathy, each, were evaluated using multivariable logistic regression. Participants (mean age, 76 years) were 56% women and 42% Black individuals. Odds of elevated florbetapir standardized uptake value ratio were significantly increased among those with atrial cardiopathy (odds ratio, 1.81; 95% CI, 1.02–3.22) and doubled for those with enlarged left atrial volume index after adjustment for demographics/risk factors (95% CI, 1.04–4.61). There was no association between P‐wave terminal force or NT‐proBNP and elevated florbetapir standardized uptake value ratio, nor between AF and elevated standardized uptake value ratio.ConclusionsAmong healthy, nondemented community‐dwelling older individuals, we report an association between atrial cardiopathy, left atrial volume index, and elevated brain amyloid, by positron emission tomography, without a similar association in individuals with AF. Potential limitations include reverse causation and survival bias. Ongoing work will help determine if changes in cardiac structure and function precede or occur simultaneously with amyloid deposition.

Orthostatic hypotension (OH) results from a failure of neural and circulatory mechanisms to compensate for the reduction in venous return that normally occurs on assuming the upright posture. OH is defined as a fall in systolic blood pressure of ≥20 mm Hg or diastolic blood pressure of ≥10 mm Hg measured within 3 minutes of standing.1 OH can result from side effects of medications, intravascular volume loss, systemic diseases that involve autonomic nerves (eg, diabetes mellitus or amyloidosis), and, in rare cases, it can be the initial sign of a primary autonomic failure syndrome (multiple system atrophy, pure autonomic failure, and Parkinson’s disease). Severe OH can be a dramatic medical condition, with affected patients unable to stand but for few seconds before disabling symptoms of cerebral hypoperfusion and syncope ensue. Asymptomatic OH is a far more common condition, but one that is often unrecognized. It is a frequent finding in the elderly, with prevalence reported between 6% and 35% or more, depending on the age group and associated comorbidities.2,3 During the past 2 decades, evidence from cross-sectional and longitudinal epidemiological studies has identified OH as an independent risk factor for cardiovascular morbidity and all-cause mortality.4 In prospective studies, the presence of OH at baseline increased the risk of subsequent adverse outcomes, including stroke,5 coronary heart disease,6 and all-cause mortality.2,4,7,8 In this …

BackgroundAmyloid plaque deposition in Alzheimer's Disease is commonly assessed using PET imaging, with the Centiloid scale serving as the standard measure for quantifying global amyloid burden. However, in addition to the Centiloid, tracer uptake in brain subregions could also provide information about the disease and its extent. In this work, we aimed to identify such brain regions whose tracer uptake information could serve as markers for AD diagnosis.MethodThe study uses PET imaging data (tracer: Pittsburgh Compound B) from the OASIS‐3 dataset, consisting of 44 cognitively normal controls and 35 mild‐moderate AD patients. The images were co‐registered to Freesurfer parcellated MRI scans and the standard uptake value ratio (SUVR) was calculated in subregions ROI, and were corrected for partial volume effects. Using Bayesian methods, a minimal but highly predictive subset of features are first identified, from which key variables associated with disease status are extracted using Markov blanket.ResultSUVRs of 23 brain regions (in addition to Centiloid) were identified as minimal feature marker subset, that are highly predictive of AD diagnosis. 6 among these 23 subregions SUVRs are directly linked to disease status in addition to global amyloid deposition measure (Centiloid). The predictive features that are strongly associated with AD include PIB uptake in regions such as Precuneus, Inferior temporal, lateral occipital and posterior cingulate regions of left cortex, supramarginal and temporal regions of right cortex and right choroid plexus.ConclusionIn this work, regional standardized uptake value ratios (SUVR) from PIB‐PET scans are analyzed to examine key brain regions linked to AD diagnosis. Tracer uptake in 13 of these regions and global amyloid deposition are identified to be highly linked to disease status, that could serve as markers and inform about the likelihood of AD in patients. Future studies could explore tracer uptake in these regions in larger cohorts to confirm their utility in AD diagnosis and treatment.Data was provided by OASIS‐3 (LaMontagne et al., 2019) and all analyses were carried out on AD Workbench (2020), Alzheimers Disease Data Initiative (https://www.alzheimersdata.org/). This work was funded by the AD Data Initiative.

Frequent Premature Atrial Contractions Are Associated With Poorer Cognitive Function in the Atherosclerosis Risk in Communities (ARIC) Study

BackgroundPublished data have highlighted associations between Alzheimer’s disease (AD) susceptibility loci and AD‐related brain changes. The amyloid imaging to prevent AD (AMYPAD) consortium is a European collaboration consisting of several parent cohorts, four of which had raw genotype array data available. We sought to integrate and harmonise the genetic data, calculate AD polygenic risk scores (PRS), and investigate their association with global amyloid deposition.MethodRaw genetic data (GRCh37) was available for 753 non‐demented participants, which underwent standard pre‐imputation quality control (QC) using PLINK. Imputation was performed using the Michigan Imputation server and HRC reference panel, and standard post‐imputation QC was done prior to the final merging of cohorts. PRSice was used for PRS calculations with Stage 1 summary statistics from Kunkle et al. (2019) as base file and European individuals from 1000 Genomes as reference for clumping. We calculated several builds of PRS at three p‐value thresholds for SNP inclusion: 5 × 10‐8, 1 × 10‐5, and 0.1. These included PRSall, PRSAPOEonly (Chr19:45‐48.8Mb), APOEε2+ ε4 (the weighted sum of the two major APOE SNPs rs429358 and rs7412), PRSnoAPOE (all SNPs excluding Chr19:45‐48.8Mb), and a composite PRSnoAPOE+APOEε2+ ε4. All were corrected for genetic principal components 1‐5 and standardised against 1000 Genomes. Cross‐sectional global amyloid burden (expressed in Centiloids) was available for everyone. Linear regression models determined if PRS were associated with amyloid deposition (age, sex, and education as covariates). Significance was based on an uncorrected p<0.05 divided by the number of SNP inclusion thresholds (N = 3).ResultParticipants were 66.9±7.6 years, 58.6% female, and 207 (27%) considered amyloid positive (CL>21). In this preliminary analysis, we found that most PRS builds were significantly associated with amyloid at all SNP inclusion thresholds assessed (Table 1, representative plots Fig. 1A,1B), except for PRSnoAPOE (Table 1, representative plot Fig. 1C).ConclusionWe highlight the significant influence of APOE in determining AD genetic predisposition, and that AD PRS are associated with amyloid deposition. Our results show that AMYPAD is a suitable cohort for studying genetic factors driving amyloid deposition before clinical onset, which we aim to extend with the inclusion of more parent cohorts, and regional and longitudinal amyloid data.

The assessment of effects associated with cognitive impairment using electroencephalography (EEG) power mapping allows the visualization of frequency-band specific local changes in oscillatory activity. In contrast, measures of coherence and dynamic source synchronization allow for the study of functional and effective connectivity, respectively. Yet, these measures have rarely been assessed in parallel in the context of mild cognitive impairment (MCI) and furthermore it has not been examined if they are related to risk factors of Alzheimer’s disease (AD) such as amyloid deposition and apolipoprotein ε4 (ApoE) allele occurrence. Here, we investigated functional and directed connectivities with Renormalized Partial Directed Coherence (RPDC) in 17 healthy controls (HC) and 17 participants with MCI. Participants underwent ApoE-genotyping and Pittsburgh compound B positron emission tomography (PiB-PET) to assess amyloid deposition. We observed lower spectral source power in MCI in the alpha and beta bands. Coherence was stronger in HC than MCI across different neuronal sources in the delta, theta, alpha, beta and gamma bands. The directed coherence analysis indicated lower information flow between fronto-temporal (including the hippocampus) sources and unidirectional connectivity in MCI. In MCI, alpha and beta RPDC showed an inverse correlation to age and gender; global amyloid deposition was inversely correlated to alpha coherence, RPDC and beta and gamma coherence. Furthermore, the ApoE status was negatively correlated to alpha coherence and RPDC, beta RPDC and gamma coherence. A classification analysis of cognitive state revealed the highest accuracy using EEG power, coherence and RPDC as input. For this small but statistically robust (Bayesian power analyses) sample, our results suggest that resting EEG related functional and directed connectivities are sensitive to the cognitive state and are linked to ApoE and amyloid burden.

Purpose To evaluate the association between the global fibrillary amyloid-β pathology and the basal forebrain connectivity at rest in cognitively intact older adults at risk for Alzheimer disease. Materials and Methods This retrospective study was approved by the local ethics committee and written informed consent was obtained from all participants. Resting-state functional connectivity (RSFC) of anterior and posterior basal forebrain seeds was investigated, as well as PET-measured global amyloid-β load by using standardized uptake value ratio (SUVR) in 267 older cognitively intact individuals with subjective memory complaints (age range, 70-85 years; overall mean age, 75.8 years; 167 women [mean age, 75.9 years] and 100 men [mean age, 75.8 years]). The participants were from the Investigation of Alzheimer's Predictors in Subjective Memory Complainers (INSIGHT-preAD) cohort (date range, 2013-present). The relationship between SUVR and the basal forebrain RSFC was assessed, followed by the effects of apolipoprotein E (APOE) genotype and sex on the basal forebrain RSFC. Results Higher SUVR values correlated with lower posterior basal forebrain RSFC in the hippocampus and the thalamus (Pearson r =-0.23; P <.001 corrected for familywise error [FWE]). Both sex and APOE genotype impacted the associations between basal forebrain RSFC and the global amyloid deposition (t values >3.59; P <.05 corrected for FWE). Conclusion Data indicate a distinct in vivo association between posterior basal forebrain dynamics and global fibrillary amyloid-β pathology in cognitively intact older adults with subjective memory complaints; both apolipoprotein E and sex moderate such association. © RSNA, 2018 Online supplemental material is available for this article. See also the editorial by Caspers in this issue.

Amyloid deposition is considered the initial pathology in Alzheimer's disease (AD). Personalized management requires investigation of amyloid pathology and the risk factors for both amyloid pathology and cognitive decline in the Chinese population. We aimed to investigate amyloid positivity and deposition in AD patients, as well as factors related to amyloid pathology in Chinese cities. This cross-sectional multicenter study was conducted in Shanghai and Zhengzhou, China. All participants were recruited from urban communities and memory clinics. Amyloid positivity and deposition were analyzed based on amyloid positron emission tomography (PET). We used partial least squares (PLS) models to investigate how related factors contributed to amyloid deposition and cognitive decline. In total, 1026 participants were included: 768 participants from the community-based cohort (COMC) and 258 participants from the clinic-based cohort (CLIC). The overall amyloid-positive rates in individuals with clinically diagnosed AD, mild cognitive impairment (MCI), and normal cognition (NC) were 85.8%, 44.5%, and 26.9%, respectively. The global amyloid deposition standardized uptake value ratios (SUVr) (reference: cerebellar crus) were 1.44 ± 0.24, 1.30 ± 0.22, and 1.24 ± 0.14, respectively. CLIC status, apolipoprotein E (ApoE) ε4, and older age were strongly associated with amyloid pathology by PLS modeling. The overall amyloid-positive rates accompanying AD, MCI, and NC in the Chinese population were similar to those in published cohorts of other populations. ApoE ε4 and CLIC status were risk factors for amyloid pathology across the AD continuum. Education was a risk factor for amyloid pathology in MCI. Female sex and age were risk factors for amyloid pathology in NC. This study provides new details about amyloid pathology in the Chinese population. Factors related to amyloid deposition and cognitive decline can help to assess patients' AD risk. • We studied amyloid pathology and related risk factors in the Chinese population. •·The overall amyloid-positive rates in individuals with clinically diagnosed AD, MCI, and NC were 85.8%, 44.5%, and 26.9%, respectively. • These overall amyloid-positive rates were in close agreement with the corresponding prevalence for other populations.

How beta-amyloid accumulation influences brain atrophy in Alzheimer's disease remains contentious with conflicting findings. We aimed to elucidate the correlations of regional longitudinal atrophy with cross-sectional regional and global amyloid in individuals with mild cognitive impairment and no cognitive impairment. We hypothesized that greater cortical thinning over time correlated with greater amyloid deposition, particularly within Alzheimer's disease characteristic regions in mild cognitive impairment, and weaker or no correlations in those with no cognitive impairment. 45 patients with mild cognitive impairment and 12 controls underwent a cross-sectional [11C]-Pittsburgh Compound B PET and two retrospective longitudinal structural imaging (follow-up: 23.65 ± 2.04 months) to assess global/regional amyloid and regional cortical thickness, respectively. Separate linear mixed models were constructed to evaluate relationships of either global or regional amyloid with regional cortical thinning longitudinally. In patients with mild cognitive impairment, regional amyloid in the right banks of the superior temporal sulcus was associated with longitudinal cortical thinning in the right medial orbitofrontal cortex (P = 0.04 after False Discovery Rate correction). In the mild cognitive impairment group, greater right banks amyloid burden and less cortical thickness in the right medial orbitofrontal cortex showed greater visual and verbal memory decline over time, which was not observed in controls. Global amyloid was not associated with longitudinal cortical thinning in any locations in either group. Our findings indicate an increasing influence of amyloid on neurodegeneration and memory along the preclinical to prodromal spectrum. Future multimodal studies that include additional biomarkers will be well-suited to delineate the interplay between various pathological processes and amyloid and memory decline, as well as clarify their additive or independent effects along the disease deterioration.

BackgroundIn our previous work, we found that amnestic mild cognitive impairment (aMCI) patients with multiple mild behavioral impairment (MBI) domain symptoms (complex group) revealed a higher risk of progression to Alzheimer's disease compared with those with no MBI symptoms (asymptomatic group) or those with only affective dysregulation (affective dysregulation group). Here, we investigated whether the MBI subgroups associated with early amyloid deposition in aMCI individuals.MethodA total 121 older adults with aMCI and 23 cognitively unimpaired (CU) individuals underwent 18F‐florbetaben (FBB) PET scans. MBI was approximated using a transformation algorithm for the neuropsychiatric inventory and participants with aMCI were classified into asymptomatic, affective dysregulation, and complex groups. PET images were corrected partial volume effect (PVE) using modified Müller‐Gärtner method. Regional standardized uptake value ratio (SUVR) maps of FBB PET were calculated by dividing the mean of the cerebellar gray matter value. Voxel‐wise comparisons of FBB SUVR maps between groups were performed using general linear model after controlling for age and sex (p < 0.05, FWE corrected; k=100). Amyloidpositivity was defined as Centiloid > 21 using the PET images without PVE correction.ResultThe 3 MBI groups of aMCI individuals showed higher prevalence of amyloid‐positive and higher values of Centiloid compared to CU individuals, however the global amyloid deposition did not differ between MBI groups in (Table 1). In voxel‐wise group comparisons, the complex group revealed higher FBB SUVRs in the bilateral precuneus, inferior temporal and angular cortices compared to CU individuals (Figure 1). The asymptomatic and affective dysregulation groups did not reveal the significant differences with CU individuals in the same statistical level. There were also no regional differences in FBB SUVRs between MBI groups. Among the amyloid‐positive patients, the complex group revealed relative lower cognitive scores compared to asymptomatic group, but the differences in cognitive function were not found in the amyloid‐negative patients (Figure 2).ConclusionThe multiple co‐occuring MBI domain symptoms in aMCI individuals were associated with higher regional amyloid deposition and severer cognitive impairment, suggesting more advanced disease stage. Therefore, evaluation of MBI could be useful for risk stratification in MCI individuals.

Subjective cognitive decline (SCD), an at-risk condition of Alzheimer's disease (AD), can involve various cognitive domains, such as memory, language, planning, and attention. We aim to explore the difference in amyloid load between the single memory domain SCD (sd-SCD) and the multidomain SCD (md-SCD) and assess the relationship of amyloid pathology with quantitative SCD scores and objective cognition. A total of 63 SCD participants from the SILCODE study underwent the clinical evaluation, neuropsychological assessment, and 18F-florbetapir PET scan. Global amyloid standard uptake value ratio (SUVr) was calculated. Additionally, regional amyloid SUVr was quantified in 12 brain regions of interests. A nonparametric rank ANCOVA was used to compare the global and regional amyloid SUVr between the md-SCD (n = 34) and sd-SCD (n = 29) groups. A multiple linear regression analysis was conducted to test the relationship of amyloid SUVr with quantitative SCD scores and objective cognition. Compared with individuals with sd-SCD, individuals with md-SCD had increased global amyloid SUVr (F = 5.033, p = 0.029) and regional amyloid SUVr in the left middle temporal gyrus (F = 12.309, p = 0.001; Bonferroni corrected), after controlling for the effects of age, sex, and education. When pooling all SCD participants together, the increased global amyloid SUVr was related with higher SCD-plus sum scores and lower Auditory Verbal Learning Test-delayed recall scores. According to our findings, individuals with md-SCD showed higher amyloid accumulation than individuals with sd-SCD, suggesting that md-SCD may experience a more advanced stage of SCD. Additionally, increased global amyloid load was predictive of a poorer episodic memory function in SCD individuals.

Evidence exists that increased levels of physical activity decrease the population burden of cardiovascular disease (CVD). Although risk factors for CVD, including plasma lipids and lipoproteins, have been associated with physical activity, studies including a sizeable number of minority participants are lacking. Our purpose was to interrogate the longitudinal effect of physical activity on plasma lipids and lipoproteins in the African American and white participants of the Atherosclerosis Risk in Communities (ARIC) Study. Nine years of follow-up data on 8,764 individuals aged 45-64 years at baseline were used in linear mixed-effects models to estimate the association between increases in baseline physical activity on mean change in HDL, LDL, total cholesterol, and triglyceride levels. Increases in the level of activity were associated with increases in HDL in all strata and decreases in triglycerides among white participants. Physical activity was associated with LDL in all women, while the association with total cholesterol was limited to African American women. This study is one of the few to investigate the effect of physical activity on lipids and lipoproteins in a race- and sex-specific manner. Overall our results highlight the importance of physical activity on plasma lipid profiles and provide evidence for novel differential associations.