The MIND diet, brain transcriptomic alterations, and dementia

Identifying novel mechanisms underlying dementia is critical to improving prevention and treatment. As an approach to mechanistic discovery, we investigated whether MIND diet (Mediterranean-DASH Diet Intervention for Neurodegenerative Delay), a consistent risk factor for dementia, is correlated with a specific profile of cortical gene expression, and whether such a transcriptomic profile is associated with dementia, in the Religious Orders Study (ROS) and Rush Memory and Aging Project (MAP). RNA sequencing (RNA-Seq) was conducted in postmortem dorsolateral prefrontal cortex tissue from 1,204 deceased participants; neuropsychological assessments were performed annually prior to death. In a subset of 482 participants, diet was assessed ~6 years before death using a validated food-frequency questionnaire; in these participants, using elastic net regression, we identified a transcriptomic profile, consisting of 50 genes, significantly correlated with MIND diet score (P=0.001). In multivariable analysis of the remaining 722 individuals, higher transcriptomic score of MIND diet was associated with slower annual rate of decline in global cognition (β=0.011 per standard deviation increment in transcriptomic profile score, P=0.003) and lower odds of dementia (odds ratio [OR] =0.76, P=0.0002). Cortical expression of several genes appeared to mediate the association between MIND diet and dementia, including TCIM, whose expression in inhibitory neurons and oligodendrocytes was associated with dementia in a subset of 424 individuals with single-nuclei RNA-seq data. In a secondary Mendelian randomization analysis, genetically predicted transcriptomic profile score was associated with dementia (OR=0.93, P=0.04). Our study suggests that associations between diet and cognitive health may involve brain molecular alterations at the transcriptomic level. Investigating brain molecular alterations related to diet may inform the identification of novel pathways underlying dementia.

Cell-type-specific Alzheimer's disease polygenic risk scores are associated with distinct disease processes in Alzheimer's disease

Alzheimer's disease (AD) heritability is enriched in glial genes, but how and when cell-type-specific genetic risk contributes to AD remains unclear. Here, we derive cell-type-specific AD polygenic risk scores (ADPRS) from two extensively characterized datasets. In an autopsy dataset spanning all stages of AD (n=1,457), astrocytic (Ast) ADPRS was associated with both diffuse and neuritic Aβ plaques, while microglial (Mic) ADPRS was associated with neuritic Aβ plaques, microglial activation, tau, and cognitive decline. Causal modeling analyses further clarified these relationships. In an independent neuroimaging dataset of cognitively unimpaired elderly (n=2,921), Ast-ADPRS were associated with Aβ, and Mic-ADPRS was associated with Aβ and tau, showing a consistent pattern with the autopsy dataset. Oligodendrocytic and excitatory neuronal ADPRSs were associated with tau, but only in the autopsy dataset including symptomatic AD cases. Together, our study provides human genetic evidence implicating multiple glial cell types in AD pathophysiology, starting from the preclinical stage.

Multi-omic characterization of brain changes in the vascular endothelial growth factor family during aging and Alzheimer's disease

The vascular endothelial growth factor (VEGF) signaling family has been implicated in neuroprotection and clinical progression in Alzheimer's disease (AD). Previous work in postmortem human dorsolateral prefrontal cortex demonstrated that higher transcript levels of VEGFB, PGF, FLT1, and FLT4 are associated with AD dementia, worse cognitive outcomes, and higher AD neuropathology. To expand prior work, we leveraged bulk RNA sequencing data, single nucleus RNA (snRNA) sequencing, and both tandem mass tag and selected reaction monitoring mass spectrometry proteomic measures from the post-mortem brain. Outcomes included AD diagnosis, cognition, and AD neuropathology. We replicated previously reported VEGFB and FLT1 results, whereby higher expression was associated with worse outcomes, and snRNA results suggest microglia, oligodendrocytes, and endothelia may play a central role in these associations. Additionally, FLT4 and NRP2 expression were associated with better cognitive outcomes. This study provides a comprehensive molecular picture of the VEGF signaling family in cognitive aging and AD and critical insight towards the biomarker and therapeutic potential of VEGF family members in AD.

Association of Mediterranean-DASH Intervention for Neurodegenerative Delay and Mediterranean Diets With Alzheimer Disease Pathology

BACKGROUND AND OBJECTIVES

Diet may reduce Alzheimer dementia risk and slow cognitive decline, but the understanding of the relevant neuropathologic mechanisms remains limited. The association of dietary patterns with Alzheimer disease (AD) pathology has been suggested using neuroimaging biomarkers. This study examined the association of Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) and Mediterranean dietary patterns with β-amyloid load, phosphorylated tau tangles, and global AD pathology in postmortem brain tissue of older adults.

METHODS

Autopsied participants of the Rush Memory and Aging Project with complete dietary information (collected through a validated food frequency questionnaire) and AD pathology data (β-amyloid load, phosphorylated tau tangles, and global AD pathology [summarized neurofibrillary tangles and neuritic and diffuse plaques]) were included in this study. Linear regression models controlled for age at death, sex, education, APOE-ε4 status, and total calories were used to investigate the dietary patterns (MIND and Mediterranean diets) and dietary components associated with AD pathology. Further effect modification was tested for APOE-ε4 status and sex.

RESULTS

Among our study participants (N = 581, age at death: 91.0 ± 6.3 years; mean age at first dietary assessment: 84.2 ± 5.8 years; 73% female; 6.8 ± 3.9 years of follow-up), dietary patterns were associated with lower global AD pathology (MIND: β = -0.022, p = 0.034, standardized β = -2.0; Mediterranean: β = -0.007, p = 0.039, standardized β = -2.3) and specifically less β-amyloid load (MIND: β = -0.068, p = 0.050, standardized β = -2.0; Mediterranean: β = -0.040, p = 0.004, standardized β = -2.9). The findings persisted when further adjusted for physical activity, smoking, and vascular disease burden. The associations were also retained when participants with mild cognitive impairment or dementia at the baseline dietary assessment were excluded. Those in the highest tertile of green leafy vegetables intake had less global AD pathology when compared with those in the lowest tertile (tertile 3 vs tertile 1: β = -0.115, p = 0.0038).

DISCUSSION

The MIND and Mediterranean diets are associated with less postmortem AD pathology, primarily β-amyloid load. Among dietary components, higher green leafy vegetable intake was associated with less AD pathology.

Estrogen Receptor Genes, Cognitive Decline, and Alzheimer Disease

BACKGROUND AND OBJECTIVES

Lifetime risk of Alzheimer disease (AD) dementia is twofold higher in women compared with men, and low estrogen levels in postmenopause have been suggested as a possible contributor. We examined 3 ER (GPER1, ER2, and ER1) variants in association with AD traits as an indirect method to test the association between estrogen and AD in women. Although the study focus was on women, in a comparison, we separately examined ER molecular variants in men.

METHODS

Participants were followed for an average of 10 years in one of the 2 longitudinal clinical pathologic studies of aging. Global cognition was assessed using a composite score derived from 19 neuropsychological tests' scores. Postmortem pathologic assessment included examination of 3 AD (amyloid-β and tau tangles determined by immunohistochemistry, and a global AD pathology score derived from diffuse and neurotic plaques and neurofibrillary tangle count) and 8 non-AD pathology indices. ER molecular genomic variants included genotyping and examining ER DNA methylation and RNA expression in brain regions including the dorsolateral prefrontal cortex (DLPFC) that are major players in cognition and often have AD pathology.

RESULTS

The mean age of women (N = 1711) at baseline was 78.0 (SD = 7.7) years. In women, GPER1 molecular variants had the most consistent associations with AD traits. GPER1 DNA methylation was associated with cognitive decline, tau tangle density, and global AD pathology score. GPER1 RNA expression in DLPFC was related to cognitive decline and tau tangle density. Other associations included associations of ER2 and ER1 sequence variants and DNA methylation with cognition. RNA expressions in DLPFC of genes involved in signaling mechanisms of activated ERs were also associated with cognitive decline and tau tangle density in women. In men (N = 651, average age at baseline: 77.4 [SD = 7.3]), there were less robust associations between ER molecular genomic variants and AD cognitive and pathologic traits. No consistent association was seen between ER molecular genomic variations and non-AD pathologies in either of the sexes.

DISCUSSION

ER DNA methylation and RNA expression, and to some extent ER polymorphisms, were associated with AD cognitive and pathologic traits in women, and to a lesser extent in men.

Trends in Postmortem Neurodegenerative and Cerebrovascular Neuropathologies Over 25 Years

Importance

With rapid aging of the US population, understanding trends over time in dementia occurrence is essential to public health planning and intervention; this understanding includes trends in neuropathologies underlying clinical dementia.

Objective

To characterize trends in pathways underlying dementia by examining prevalence of postmortem neuropathologies in birth cohorts across 25 years.

Design, Setting, and Participants

Two longitudinal cohorts, the Religious Orders Study and the Rush Memory and Aging Project, with autopsy data from 1997 to 2022 with up to 27 years follow-up were analyzed. Deceased individuals with complete postmortem neuropathology evaluations were included, and 177 individuals with most distant (<1905) or recent (>1930) years of birth were excluded.

Exposures

Four categories of year of birth: 1905-1914, 1915-1919, 1920-1924, and 1925-1930.

Main Outcomes and Measures

Outcomes included pathologic diagnosis of Alzheimer disease (AD), global AD pathology, amyloid load, tau tangles, neocortical Lewy bodies, limbic-predominant age-related TDP-43 encephalopathy neuropathological change, atherosclerosis, arteriolosclerosis, gross chronic infarcts, and chronic microinfarcts. For comparison, pathologies in each birth epoch were age-standardized to age distribution of the cohorts. χ2 Tests were used for categorical outcomes, and analysis of variance was used to compare means across birth epochs.

Results

Overall, 1554 participants were examined (510 [33%] male; median [range] age at death, 90 [66-108] years). Participants were distributed fairly evenly across birth epochs (1905-1914: n = 374; 1915-1919: n = 360; 1920-1924: n = 466; 1925-1930: n = 354). Across year of birth groups, no differences were found in prevalence of pathologic AD diagnosis; age-standardized prevalence fluctuated between 62% and 68% in the birth cohorts (χ2 test: P = .76 across birth epochs). Similarly, no differences were found in mean levels of global AD pathology, although there was greater density specifically of tau tangles in later birth cohorts (eg, age-standardized mean [SD], 1.53 [1.20] years for the 1905-1914 cohort and 1.87 [1.47] years for the 1925-1930 cohort; analysis of variance test: P = .01 across birth cohorts). There were no differences over time in other neurodegenerative pathologies. In contrast, atherosclerosis and arteriosclerosis were dramatically lower over time; for example, age-standardized prevalence of moderate to severe atherosclerosis ranged from 54% among those born from 1905-1914 to 22% for 1925-1930 (χ2 test: P < .001 across birth epochs).

Conclusion and Relevance

In this study, few differences in neurodegenerative pathologies were found, but there may be worse levels of tau tangles across birth cohorts over 25 years. This indicates that any improvements over time in clinical dementia observed by cohorts are likely in part associated with improved resilience to pathology rather than reduced AD pathology. Finally, vessel pathologies were markedly lower over birth cohorts, indicating the assocation with brain health of populationwide improvements in several vascular risk factors.

Neurodegenerative and Cerebrovascular Brain Pathologies Are Differentially Associated With Declining Grip Strength and Gait In Older Adults

BACKGROUND

Understanding the pathological bases underlying the heterogeneity of motor decline in old age may lead to targeted treatments. We examined whether different brain pathologies are related to declining grip strength and gait function.

METHODS

We examined postmortem brains of older adults who underwent annual motor testing. Postmortem exam measured 6 neurodegenerative and 5 cerebrovascular disease (CVD) pathologies. Grip strength was measured twice bilaterally using a hand-held dynamometer, and gait function was a composite measure based on time and steps taken to walk 8 ft and perform a 360° turn twice.

RESULTS

In separate linear mixed-effects models including all autopsied adults (N = 1 217), neurodegenerative pathologies including tau tangles, TDP-43, and nigral neuronal loss were associated with declining grip strength, but not CVD pathologies. In contrast, although both CVD and neurodegenerative pathologies were associated with declining gait function, CVD pathologies accounted for 75% of the variance of declining rate of gait function explained by brain pathologies and neurodegenerative pathologies accounted for 25%. These findings were unchanged in adults (n = 970) without a history of stroke. Restricting analyses to only adults without dementia (n = 661), CVD pathologies continued to account for the majority of the variance of declining gait. However, we failed to detect in this subgroup the variance of declining grip strength explained by neurodegenerative or CVD pathologies.

CONCLUSION

Different pathologies accumulating in aging brains may contribute to the phenotypic heterogeneity of motor decline. Larger studies are needed in older adults without dementia to assess differences in the motor consequences of varied brain pathologies.

Brain β-Amyloid Links the Association of Change in Body Mass Index With Cognitive Decline in Community-Dwelling Older Adults

BACKGROUND

We tested the hypothesis that indices of Alzheimer's disease and related dementia (ADRD) pathologies may explain associations between change in body mass index (BMI) and cognitive decline in old age.

METHOD

We used data from 436 older decedents participating in a prospective longitudinal cohort study who had undergone annual cognitive and BMI assessments and postmortem collection of indices of 12 brain pathologies. We identified ADRD brain pathologies associated with BMI range, a previously published metric of change in BMI. We employed sigmoidal mixed-effect models of cognitive decline to examine the associations of change in BMI and cognitive decline with and without terms for ADRD brain pathologies.

RESULTS

Average age at baseline was 78.6 years, SD = 6.5 years with 64% female. On average, 9 cognitive assessments were obtained with average age at death 88.4 years (SD = 6.2 years). Change in BMI as measured by BMI range was associated with cognitive decline (θ 2 = 0.260). β-Amyloid, hippocampal sclerosis, and substantia nigra neuronal loss were associated with BMI range. β-Amyloid strongly attenuated the association of BMI range with cognitive decline. Hippocampal sclerosis showed only partial attenuation of the association of BMI range and cognitive decline and nigral neuronal loss did not attenuate this association.

CONCLUSION

Changes in BMI and cognitive decline in older adults may be affected by similar mechanisms underlying the accumulation of brain pathologies like β-amyloid in aging brains. Elucidating the molecular mechanisms underlying these associations may provide novel targets for developing interventions that maintain brain health and metabolic homeostasis in old age.

The status of digital pathology and associated infrastructure within Alzheimer's Disease Centers

Digital pathology (DP) has transformative potential, especially for Alzheimer disease and related disorders. However, infrastructure barriers may limit adoption. To provide benchmarks and insights into implementation barriers, a survey was conducted in 2019 within National Institutes of Health's Alzheimer's Disease Centers (ADCs). Questions covered infrastructure, funding sources, and data management related to digital pathology. Of the 35 ADCs to which the survey was sent, 33 responded. Most respondents (81%) stated that their ADC had digital slide scanner access, with the most frequent brand being Aperio/Leica (62.9%). Approximately a third of respondents stated there were fees to utilize the scanner. For DP and machine learning (ML) resources, 41% of respondents stated none was supported by their ADC. For scanner purchasing and operations, 50% of respondents stated they received institutional support. Some were unsure of the file size of scanned digital images (37%) and total amount of storage space files occupied (50%). Most (76%) were aware of other departments at their institution working with ML; a similar (76%) percentage were unaware of multiuniversity or industry partnerships. These results demonstrate many ADCs have access to a digital slide scanner; additional investigations are needed to further understand hurdles to implement DP and ML workflows.

Association of Dietary Intake of Flavonols With Changes in Global Cognition and Several Cognitive Abilities

BACKGROUND AND OBJECTIVES

Previous research has examined the association between cognition and flavonoids: bioactives found in foods, known to possess anti-inflammatory and antioxidant properties. We extend this research by investigating associations of dietary intakes of total flavonols and constituents (kaempferol, quercetin, myricetin, and isorhamnetin) on the change in cognitive performance in global cognition, episodic memory, semantic memory, visuospatial ability, perceptual speed, and working memory.

METHODS

The study was conducted using 961 participants (aged 60-100 years) of the Rush Memory and Aging Project, a prospective cohort of community-dwelling Chicagoans who were followed for an average of 6.9 years. Diet was assessed using a validated semiquantitative food frequency questionnaire. Cognitive performance was assessed annually with a battery of 19 standardized tests. Flavonol intake was analyzed as a continuous variable using linear mixed-effects models. Cognitive domain scores were regressed on baseline calorie-adjusted flavonol variables.

RESULTS

Higher dietary intakes of total flavonols and flavonol constituents were associated with a slower rate of decline in global cognition and multiple cognitive domains. In continuous models adjusted for age, sex, education, APOE ɛ4, late-life cognitive activity, physical activity, and smoking, total flavonol intake was associated with slower decline in global cognition β estimate = 0.004 (95% CI 0.001-0.006), episodic memory β = 0.004 (95% CI 0.002-0.006), semantic memory β = 0.003 (95% CI 0.001-0.007), perceptual speed β = 0.003 (95% CI 0.001-0.004), and working memory β = 0.003 (95% CI 0.001-0.005) and marginally associated with visuospatial ability β = 0.001 (95% CI -0.001 to 0.003). Analyses of individual flavonol constituents demonstrated that intakes of kaempferol and quercetin were associated with slower global cognitive decline (β = 0.01 [95% CI 0.006-0.02] and β = 0.004 [95% CI 0.0005-0.007]), respectively. Myricetin and isorhamnetin were not associated with global cognition.

DISCUSSION

Results suggest that dietary intakes of total flavonols and several flavonol constituents may be associated with slower decline in global cognition and multiple cognitive abilities with older age.

Neuropathology of the Common Forms of Dementia

Dementias encompass a range of debilitating neurologic conditions. Here, we summarize the neuropathology of common forms of dementia, focusing on Alzheimer disease (AD) and related dementias. AD is part of a spectrum of neurodegenerative diseases that consists of various protein inclusions (ie, proteinopathies) but other brain abnormalities are also related to dementia. Beta-amyloid and tau aggregates are hallmarks of AD. Other tissue substrates include Lewy bodies, TDP-43 inclusions, vascular brain lesions, and mixed pathologies. This review highlights the complexity of neurodegenerative and other disease substrates and summarizes topography of these lesions and concepts of mixed brain pathologies, resistance, and resilience.

Brain and spinal cord arteriolosclerosis and its associations with cerebrovascular disease risk factors in community-dwelling older adults

Arteriolosclerosis is common in older brains and related to cognitive and motor impairment. We compared the severity of arteriolosclerosis and its associations with cerebrovascular disease risk factors (CVD-RFs) in multiple locations in the brain and spinal cord. Participants (n = 390) were recruited in the context of a longitudinal community-based clinical-pathological study, the Rush Memory and Aging Project. CVD-RFs were assessed annually for an average of 8.7 (SD = 4.3) years before death. The annual assessments included systolic (SBP) and diastolic (DBP) blood pressure, diabetes mellitus (DM), low- and high-density lipoprotein cholesterol, triglyceride, body mass index, and smoking. Postmortem pathological assessments included assessment of arteriolosclerosis severity using the same rating scale in three brain locations (basal ganglia, frontal, and parietal white matter regions) and four spinal cord levels (cervical, thoracic, lumbar and sacral levels). A single measure was used to summarize the severity of spinal arteriolosclerosis assessments at the four levels due to their high correlations. Average age at death was 91.5 (SD = 6.2) years, and 73% were women. Half showed arteriolosclerosis in frontal white matter and spinal cord followed by parietal white matter (38%) and basal ganglia (27%). The severity of arteriolosclerosis in all three brain locations showed mild-to-moderate correlations. By contrast, spinal arteriolosclerosis was associated with brain arteriolosclerosis only in frontal white matter. Higher DBP was associated with more severe arteriolosclerosis in all three brain locations. DM was associated with more severe arteriolosclerosis only in frontal white matter. Controlling for DBP, higher SBP was inversely associated with arteriolosclerosis in parietal white matter. Blood cholesterol and triglyceride, high body mass index, or smoking were not related to the severity of arteriolosclerosis in any brain region. None of the CVD-RFs were associated with the severity of spinal arteriolosclerosis. These data indicate that severity of arteriolosclerosis and its associations with CVD-RFs may vary in different CNS locations.

LATE-NC staging in routine neuropathologic diagnosis: an update

An international consensus report in 2019 recommended a classification system for limbic-predominant age-related TDP-43 encephalopathy neuropathologic changes (LATE-NC). The suggested neuropathologic staging system and nomenclature have proven useful for autopsy practice and dementia research. However, some issues remain unresolved, such as cases with unusual features that do not fit with current diagnostic categories. The goal of this report is to update the neuropathologic criteria for the diagnosis and staging of LATE-NC, based primarily on published data. We provide practical suggestions about how to integrate available genetic information and comorbid pathologies [e.g., Alzheimer's disease neuropathologic changes (ADNC) and Lewy body disease]. We also describe recent research findings that have enabled more precise guidance on how to differentiate LATE-NC from other subtypes of TDP-43 pathology [e.g., frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS)], and how to render diagnoses in unusual situations in which TDP-43 pathology does not follow the staging scheme proposed in 2019. Specific recommendations are also made on when not to apply this diagnostic term based on current knowledge. Neuroanatomical regions of interest in LATE-NC are described in detail and the implications for TDP-43 immunohistochemical results are specified more precisely. We also highlight questions that remain unresolved and areas needing additional study. In summary, the current work lays out a number of recommendations to improve the precision of LATE-NC staging based on published reports and diagnostic experience.

The Caribbean-Hispanic Alzheimer's disease brain transcriptome reveals ancestry-specific disease mechanisms

Identifying ancestry-specific molecular profiles of late-onset Alzheimer's Disease (LOAD) in brain tissue is crucial to understand novel mechanisms and develop effective interventions in non-European, high-risk populations. We performed gene differential expression (DE) and consensus network-based analyses in RNA-sequencing data of postmortem brain tissue from 39 Caribbean Hispanics (CH). To identify ancestry-concordant and -discordant expression profiles, we compared our results to those from two independent non-Hispanic White (NHW) samples (n = 731). In CH, we identified 2802 significant DE genes, including several LOAD known-loci. DE effects were highly concordant across ethnicities, with 373 genes transcriptome-wide significant in all three cohorts. Cross-ancestry meta-analysis found NPNT to be the top DE gene. We replicated over 82% of meta-analyses genome-wide signals in single-nucleus RNA-seq data (including NPNT and LOAD known-genes SORL1, FBXL7, CLU, ABCA7). Increasing representation in genetic studies will allow for deeper understanding of ancestry-specific mechanisms and improving precision treatment options in understudied groups.

Vesicular Glutamate Transporter Changes in the Cortical Default Mode Network During the Clinical and Pathological Progression of Alzheimer's Disease

BACKGROUND

Altered glutamatergic neurotransmission may contribute to impaired default mode network (DMN) function in Alzheimer's disease (AD). Among the DMN hub regions, frontal cortex (FC) was suggested to undergo a glutamatergic plasticity response in prodromal AD, while the status of glutamatergic synapses in the precuneus (PreC) during clinical-neuropathological AD progression is not known.

OBJECTIVE

To quantify vesicular glutamate transporter VGluT1- and VGluT2-containing synaptic terminals in PreC and FC across clinical stages of AD.

METHODS

Unbiased sampling and quantitative confocal immunofluorescence of cortical VGluT1- and VGluT2-immunoreactive profiles and spinophilin-labeled dendritic spines were performed in cases with no cognitive impairment (NCI), mild cognitive impairment (MCI), mild-moderate AD (mAD), or moderate-severe AD (sAD).

RESULTS

In both regions, loss of VGluT1-positive profile density was seen in sAD compared to NCI, MCI, and mAD. VGluT1-positive profile intensity in PreC did not differ across groups, while in FC it was greater in MCI, mAD, and sAD compared to NCI. VGluT2 measures were stable in PreC while FC had greater VGluT2-positive profile density in MCI compared to sAD, but not NCI or mAD. Spinophilin measures in PreC were lower in mAD and sAD compared to NCI, while in FC they were stable across groups. Lower VGluT1 and spinophilin measures in PreC, but not FC, correlated with greater neuropathology.

CONCLUSION

Frank loss of VGluT1 in advanced AD relative to NCI occurs in both DMN regions. In FC, an upregulation of VGluT1 protein content in remaining glutamatergic terminals may contribute to this region's plasticity response in AD.

Association of Stroke and Cerebrovascular Pathologies With Scam Susceptibility in Older Adults

Importance

Scam susceptibility is associated with adverse financial and health outcomes, including an increased risk of cognitive decline and dementia. Very little is known about the role of cerebrovascular pathologies with scam susceptibility.

Objective

To examine the association of diverse cerebrovascular pathologies (globally and regionally) with scam susceptibility.

Design, setting, and Participants

This clinical-pathological cohort study included participants from 2 ongoing studies of aging that began enrollment in 1994 and 1997. In 2010, participants were enrolled in the decision-making and behavioral economics substudy and were followed up for a mean (SD) of 3.4 (2.6) years prior to death. From 1365 older persons with clinical evaluations, 69 were excluded for having dementia at baseline. From 538 older persons who died, 408 had annual assessments for scam susceptibility, cardiovascular risk burden, and cognitive function and consented to brain donation for detailed neuropathologic examination. Data were analyzed from June 2021 through September 2022.

Exposures

Neuropathologic examination identified the presence of macroscopic and microscopic infarcts, atherosclerosis, arteriolosclerosis, cerebral amyloid angiopathy, and common neurodegenerative pathologies (Alzheimer disease, limbic-predominant age-related transactive response DNA-binding protein 43 encephalopathy, and Lewy bodies).

Results

There was a total of 408 participants. The mean (SD) age at death was 91 (6.1) years, the mean (SD) amount of education was 15.6 (3.1) years, and 297 (73%) were women. Participants included 4 Latino individuals (1%), 7 non-Latino Black individuals (2%), and 397 non-Latino White individuals (97%). The frequency of participants with macroscopic infarcts was 38% (n = 154), microinfarcts was 40% (n = 163), and moderate to severe vessel disease; specifically, atherosclerosis was 20% (n = 83), arteriolosclerosis was 25% (n = 100), and cerebral amyloid angiopathy was 35% (n = 143). In linear regression models adjusted for demographics and neurodegenerative pathologies, macroscopic infarcts were associated with greater scam susceptibility (estimate [SE], 0.18 [0.07]; P = .009). This association persisted after adjusting for cardiovascular risk burden and global cognition. Regionally, infarcts localized to the frontal, temporal, and occipital lobes and thalamus were associated with greater scam susceptibility. Neither arteriosclerosis, atherosclerosis, cerebral amyloid angiopathy, nor microinfarcts were associated with scam susceptibility.

Conclusions and Relevance

Cerebrovascular pathologies, specifically cerebral infarcts, is linked with greater scam susceptibility in older adults, independent of common neurodegenerative diseases such as Alzheimer disease. Future studies examining in vivo magnetic resonance imaging markers of cerebrovascular pathologies with scam susceptibility and related decision-making outcomes will be important.

TDP-43 Pathology in the Setting of Intermediate and High Alzheimer's Disease Neuropathologic Changes: A Preliminary Evaluation Across Ethnoracial Groups

BACKGROUND

Transactive Response DNA Binding Protein 43 kDa (TDP-43) pathology is frequently found in cases with Alzheimer's disease (AD). TDP-43 pathology is associated with hippocampal atrophy and greater AD severity denoted by cognition and clinical representation. Current TDP-43 pathology studies are predominantly based on non-Hispanic White cohorts.

OBJECTIVE

We sought to evaluate the presence of TDP-43 pathology across ethnoracial groups utilizing the National Alzheimer's Coordinating Center; a database containing data from over 29 institutions across the United States. Cases (N = 1135: Hispanics/Latinos = 29, African Americans/Black Americans = 51, Asians/Asian Americans = 10, American Indians/Alaskan Natives = 2, non-Hispanic White = 1043) with intermediate/high AD having data on TDP-43 pathology in the amygdala, hippocampus, entorhinal cortex, and neocortex were included.

METHODS

TDP-43 pathology frequency in each neuroanatomic region among ethnoracial groups were compared using generalized linear mixed effects models with center as a random effect adjusting for age at death, education, and gender.

RESULTS

Although groups were imbalanced, there was no significant difference across ethnoracial groups based on TDP-43 pathology (p = 0.84). With respect to neuroanatomical regions evaluated, there were no significant differences across ethnoracial groups (p-values > 0.06). There were also no significant differences for age at death and gender ratios across ethnoracial groups based on TDP-43 pathology. Although not statistically significant, TDP-43 pathology was present less often in Hispanic/Latinos (34%) when compared to non-Hispanic Whites (46%).

CONCLUSION

While this is a preliminary evaluation, it highlights the need for diverse cohorts and on TDP-43 pathology research across ethnoracial groups. This is the first study to our knowledge having a focus on the neuroanatomical distribution of TDP-43 deposits in Hispanic/Latino decedents with AD.

Multi-Site Cross-Site Inter-Rater and Test-Retest Reliability and Construct Validity of the MarkVCID White Matter Hyperintensity Growth and Regression Protocol

BACKGROUND

White matter hyperintensities (WMH) that occur in the setting of vascular cognitive impairment and dementia (VCID) may be dynamic increasing or decreasing volumes or stable over time. Quantifying such changes may prove useful as a biomarker for clinical trials designed to address vascular cognitive-impairment and dementia and Alzheimer's Disease.

OBJECTIVE

Conducting multi-site cross-site inter-rater and test-retest reliability of the MarkVCID white matter hyperintensity growth and regression protocol.

METHODS

The NINDS-supported MarkVCID Consortium evaluated a neuroimaging biomarker developed to track WMH change. Test-retest and cross-site inter-rater reliability of the protocol were assessed. Cognitive test scores were analyzed in relation to WMH changes to explore its construct validity.

RESULTS

ICC values for test-retest reliability of WMH growth and regression were 0.969 and 0.937 respectively, while for cross-site inter-rater ICC values for WMH growth and regression were 0.995 and 0.990 respectively. Word list long-delay free-recall was negatively associated with WMH growth (p < 0.028) but was not associated with WMH regression.

CONCLUSIONS

The present data demonstrate robust ICC validity of a WMH growth/regression protocol over a one-year period as measured by cross-site inter-rater and test-retest reliability. These data suggest that this approach may serve an important role in clinical trials of disease-modifying agents for VCID that may preferentially affect WMH growth, stability, or regression.

Brain autopsies of critically ill COVID-19 patients demonstrate heterogeneous profile of acute vascular injury, inflammation and age-linked chronic brain diseases

BACKGROUND

This study examined neuropathological findings of patients who died following hospitalization in an intensive care unit with SARS-CoV-2.

METHODS

Data originate from 20 decedents who underwent brain autopsy followed by ex-vivo imaging and dissection. Systematic neuropathologic examinations were performed to assess histopathologic changes including cerebrovascular disease and tissue injury, neurodegenerative diseases, and inflammatory response. Cerebrospinal fluid (CSF) and fixed tissues were evaluated for the presence of viral RNA and protein.

RESULTS

The mean age-at-death was 66.2 years (range: 26-97 years) and 14 were male. The patient's medical history included cardiovascular risk factors or diseases (n = 11, 55%) and dementia (n = 5, 25%). Brain examination revealed a range of acute and chronic pathologies. Acute vascular pathologic changes were common in 16 (80%) subjects and included infarctions (n = 11, 55%) followed by acute hypoxic/ischemic injury (n = 9, 45%) and hemorrhages (n = 7, 35%). These acute pathologic changes were identified in both younger and older groups and those with and without vascular risk factors or diseases. Moderate-to-severe microglial activation were noted in 16 (80%) brains, while moderate-to-severe T lymphocyte accumulation was present in 5 (25%) brains. Encephalitis-like changes included lymphocytic cuffing (n = 6, 30%) and neuronophagia or microglial nodule (most prominent in the brainstem, n = 6, 30%) were also observed. A single brain showed vasculitis-like changes and one other exhibited foci of necrosis with ball-ring hemorrhages reminiscent of acute hemorrhagic leukoencephalopathy changes. Chronic pathologies were identified in only older decedents: 7 brains exhibited neurodegenerative diseases and 8 brains showed vascular disease pathologies. CSF and brain samples did not show evidence of viral RNA or protein.

CONCLUSIONS

Acute tissue injuries and microglial activation were the most common abnormalities in COVID-19 brains. Focal evidence of encephalitis-like changes was noted despite the lack of detectable virus. The majority of older subjects showed age-related brain pathologies even in the absence of known neurologic disease. Findings of this study suggest that acute brain injury superimposed on common pre-existing brain disease may put older subjects at higher risk of post-COVID neurologic sequelae.

Brain vitamin D forms, cognitive decline, and neuropathology in community‐dwelling older adults

INTRODUCTION

Vitamin D purportedly protects against cognitive decline and dementia based on observational data using circulating 25-hydroxyvitamin D (25(OH)D). Little is known about vitamin D in the human brain and the association with dementia or neuropathology.

METHODS

Decedents of the Rush Memory and Aging Project (n = 290) had vitamin D concentrations measured in four brain regions. Associations with cognitive and neuropathological outcomes were estimated using linear and logistic regression.

RESULTS

The main form of vitamin D in all brain regions measured was 25(OH)D₃ . Higher brain 25(OH)D₃ concentrations were associated with a 25% to 33% lower odds of dementia or mild cognitive impairment (MCI) at the last visit before death (all P ≤ .031). However, brain 25(OH)D concentrations were not associated with any post-mortem neuropathology outcome studied.

DISCUSSION

Higher brain 25(OH)D₃ concentrations were associated with better cognitive function prior to death. Additional research is needed to clarify the specific mechanisms underlying this potentially protective relationship.

Arachnoid granulations are lymphatic conduits that communicate with bone marrow and dura-arachnoid stroma

Arachnoid granulations (AG) are poorly investigated. Historical reports suggest that they regulate brain volume by passively transporting cerebrospinal fluid (CSF) into dural venous sinuses. Here, we studied the microstructure of cerebral AG in humans with the aim of understanding their roles in physiology. We discovered marked variations in AG size, lobation, location, content, and degree of surface encapsulation. High-resolution microscopy shows that AG consist of outer capsule and inner stromal core regions. The fine and porous framework suggests uncharacterized functions of AG in mechanical CSF filtration. Moreover, internal cytokine and immune cell enrichment imply unexplored neuroimmune properties of these structures that localize to the brain-meningeal lymphatic interface. Dramatic age-associated changes in AG structure are additionally identified. This study depicts for the first time microscopic networks of internal channels that communicate with perisinus spaces, suggesting that AG subserve important functions as transarachnoidal flow passageways. These data raise new theories regarding glymphatic-lymphatic coupling and mechanisms of CSF antigen clearance, homeostasis, and diseases.

Progranulin mutations in clinical and neuropathological Alzheimer's disease

INTRODUCTION

Progranulin (GRN) mutations occur in frontotemporal lobar degeneration (FTLD) and in Alzheimer's disease (AD), often with TDP-43 pathology.

METHODS

We determined the frequency of rs5848 and rare, pathogenic GRN mutations in two autopsy and one family cohort. We compared Braak stage, β-amyloid load, hyperphosphorylated tau (PHFtau) tangle density and TDP-43 pathology in GRN carriers and non-carriers.

RESULTS

Pathogenic GRN mutations were more frequent in all cohorts compared to the Genome Aggregation Database (gnomAD), but there was no evidence for association with AD. Pathogenic GRN carriers had significantly higher PHFtau tangle density adjusting for age, sex and APOE ε4 genotype. AD patients with rs5848 had higher frequencies of hippocampal sclerosis and TDP-43 deposits. Twenty-two rare, pathogenic GRN variants were observed in the family cohort.

DISCUSSION

GRN mutations in clinical and neuropathological AD increase the burden of tau-related brain pathology but show no specific association with β-amyloid load or AD.

Frequency and Underlying Pathology of Pure Vascular Cognitive Impairment

Importance

It is not clear how common pure vascular cognitive impairment (VCI) is in the absence of Alzheimer disease (AD) and/or other neurodegenerative pathologies.

Objective

To identify participants without AD and other neurodegenerative pathologies and determine the extent to which cerebrovascular disease pathologies were associated with cognitive impairment.

Design, Setting, and Participants

This clinical pathological study included participants from 2 ongoing community-based cohorts that began enrollment in 1994 and 1997. Prior to death, participants were observed for a mean (SD) of 8.4 (5.3) years with annual assessments. From 2096 participants who died, 1799 (85.8%) underwent autopsy and 1767 had complete postmortem pathological examination data at the time of data analyses. To identify participants without neurodegenerative pathologies, we categorized them in 3 subgroups. A vascular subgroup was composed of participants without significant levels of neurodegenerative brain pathologies. A neurodegenerative subgroup was composed of participants without significant levels of cerebrovascular disease pathologies. A mixed subgroup was composed of the rest of the participants. Data were analyzed from May 2021 to July 2022.

Exposures

Brain pathology indices obtained by postmortem pathological assessments.

Main Outcomes and Measures

The primary outcome was cognitive impairment defined by presence of mild cognitive impairment or dementia. The secondary outcome was cognition assessed by 19 neuropsychological tests.

Results

Of 1767 included participants, 1189 (67.3%) were women, and the mean (SD) age at death was 89.4 (6.6) years. In the vascular subgroup (n = 369), cognitive impairment was present in 156 participants (42.3%) and was associated with cerebrovascular disease pathologies (macroinfarcts: odds ratio [OR], 2.05; 95% CI, 1.49-2.82; P < .001; arteriolosclerosis in basal ganglia: OR, 1.35; 95% CI, 1.04-1.76; P = .03) but not AD or other neurodegenerative pathologies, an indication of pure VCI. In mixed-effects models including all the pathologies, only macroinfarcts were associated with a faster cognitive decline rate (estimate, -0.019; SE, 0.005; P < .001) in the vascular subgroup. Further analyses identified macroinfarcts in the frontal white matter to be associated with faster cognitive decline rate when macroinfarcts of cortical and subcortical brain regions were examined in a single model.

Conclusions and Relevance

In this study, pure VCI was not rare. Macroinfarcts, specifically in frontal white matter, were the main cerebrovascular disease pathologies associated with cognitive decline in pure VCI.

Association of AK4 Protein From Stem Cell-Derived Neurons With Cognitive Reserve: An Autopsy Study

BACKGROUND AND OBJECTIVES

Identifying protein targets that provide cognitive reserve is a strategy to prevent and treat Alzheimer disease and Alzheimer disease related dementias (AD/ADRD). Previous studies using bulk human brain tissue reported 12 proteins associated with cognitive reserve. This study examined whether the same proteins from induced neurons (iNs) are associated with cognitive reserve of their human donors.

METHODS

Induced pluripotent stem cell (iPSC) lines were generated from cryopreserved peripheral blood mononuclear cells of older adults who were autopsied as part of the Religious Orders Study or Rush Memory and Aging Project. Neurons were induced from iPSCs using a standard neurogenin2 protocol. Tandem mass tag proteomics analyses were conducted on iNs day 21. Cognitive reserve of their human donors was measured as person-specific slopes of cognitive change not accounted for by common neuropathologies.

RESULTS

The 53 human donors died at a mean age of 91 years, all were non-Latino White, and 36 (67.9%) were female. Eighteen were diagnosed with Alzheimer dementia proximate to death, and 34 had pathologic AD diagnosis at autopsy. Approximately 60% of the donors had above-average cognitive reserve such that their cognition declined slower than an average person with comparable burdens of neuropathologies. Eight of the 12 candidate proteins were quantified in iNs proteomics analyses. Higher adenylate kinase 4 (AK4) expression in iNs was associated with lower cognitive reserve, consistent with the previous report for brain AK4 expression.

DISCUSSION

By replicating cortical protein associations with cognitive reserve in human iNs, these data provide a valuable molecular readout for studying complex clinical phenotypes such as cognitive reserve in a dish.

Co-expression network analysis of frontal cortex during the progression of Alzheimer's disease

Mechanisms of Alzheimer's disease (AD) and its putative prodromal stage, amnestic mild cognitive impairment (aMCI), involve the dysregulation of multiple candidate molecular pathways that drive selective cellular vulnerability in cognitive brain regions. However, the spatiotemporal overlap of markers for pathway dysregulation in different brain regions and cell types presents a challenge for pinpointing causal versus epiphenomenal changes characterizing disease progression. To approach this problem, we performed Weighted Gene Co-expression Network Analysis and STRING interactome analysis of gene expression patterns quantified in frontal cortex samples (Brodmann area 10) from subjects who died with a clinical diagnosis of no cognitive impairment, aMCI, or mild/moderate AD. Frontal cortex was chosen due to the relatively protracted involvement of this region in AD, which might reveal pathways associated with disease onset. A co-expressed network correlating with clinical diagnosis was functionally associated with insulin signaling, with insulin (INS) being the most highly connected gene within the network. Co-expressed networks correlating with neuropathological diagnostic criteria (e.g., NIA-Reagan Likelihood of AD) were associated with platelet-endothelium-leucocyte cell adhesion pathways and hypoxia-oxidative stress. Dysregulation of these functional pathways may represent incipient alterations impacting disease progression and the clinical presentation of aMCI and AD.

Multiple gene variants linked to Alzheimer's-type clinical dementia via GWAS are also associated with non-Alzheimer's neuropathologic entities

The classic pathologic hallmarks of Alzheimer's disease (AD) are amyloid plaques and neurofibrillary tangles (AD neuropathologic changes, or ADNC). However, brains from individuals clinically diagnosed with "AD-type" (amnestic) dementia usually harbor heterogeneous neuropathologies in addition to, or other than, ADNC. We hypothesized that some AD-type dementia associated genetic single nucleotide variants (SNVs) identified from large genomewide association studies (GWAS) were associated with non-ADNC neuropathologies. To test this hypothesis, we analyzed data from multiple studies with available genotype and neuropathologic phenotype information. Clinical AD/dementia risk alleles of interest were derived from the very large GWAS by Bellenguez et al. (2022) who reported 83 clinical AD/dementia-linked SNVs in addition to the APOE risk alleles. To query the pathologic phenotypes associated with variation of those SNVs, National Alzheimer's disease Coordinating Center (NACC) neuropathologic data were linked to AD Sequencing Project (ADSP) and AD Genomics Consortium (ADGC) data. Separate data were obtained from the harmonized Religious Orders Study and the Rush Memory and Aging Project (ROSMAP). A total of 4811 European participants had at least ADNC neuropathology data and also genotype data available; data were meta-analyzed across cohorts. As expected, a subset of dementia-associated SNVs were associated with ADNC risk in Europeans-e.g., BIN1, PICALM, CR1, MME, and COX7C. Other gene variants linked to (clinical) AD dementia were associated with non-ADNC pathologies. For example, the associations of GRN and TMEM106B SNVs with limbic-predominant age-related TDP-43 neuropathologic changes (LATE-NC) were replicated. In addition, SNVs in TNIP1 and WNT3 previously reported as AD-related were instead associated with hippocampal sclerosis pathology. Some genotype/neuropathology association trends were not statistically significant at P < 0.05 after correcting for multiple testing, but were intriguing. For example, variants in SORL1 and TPCN1 showed trends for association with LATE-NC whereas Lewy body pathology trended toward association with USP6NL and BIN1 gene variants. A smaller cohort of non-European subjects (n = 273, approximately one-half of whom were African-Americans) provided the basis for additional exploratory analyses. Overall, these findings were consistent with the hypothesis that some genetic variants linked to AD dementia risk exert their affect by influencing non-ADNC neuropathologies.

RNASE6 is a novel modifier of APOE-ε4 effects on cognition

Apolipoprotein E4 (APOE-ε4), the strongest common genetic risk factor for Alzheimer's disease (AD), contributes to worse cognition in older adults. However, many APOE-ε4 carriers remain cognitively normal throughout life, suggesting that neuroprotective factors may be present in these individuals. In this study, we leverage whole-blood RNA sequencing (RNAseq) from 324 older adults to identify genetic modifiers of APOE-ε4 effects on cognition. Expression of RNASE6 interacted with APOE-ε4 status (p = 4.35 × 10^-8) whereby higher RNASE6 expression was associated with worse memory at baseline among APOE-ε4 carriers. This interaction was replicated using RNAseq data from the prefrontal cortex in an independent dataset (N = 535; p = 0.002), suggesting the peripheral effect of RNASE6 is also present in brain tissue. RNASE6 encodes an antimicrobial peptide involved in innate immune response and has been previously observed in a gene co-expression network module with other AD-related inflammatory genes, including TREM2 and MS4A. Together, these data implicate neuroinflammation in cognitive decline, and suggest that innate immune signaling may be detectable in blood and confer differential susceptibility to AD depending on APOE-ε4.

Limbic-predominant age-related TDP-43 encephalopathy neuropathological change (LATE-NC) is associated with lower R2 relaxation rate: an ex-vivo MRI and pathology investigation

Limbic predominant age-related transactive response DNA binding protein 43 (TDP-43) encephalopathy neuropathological change (LATE-NC) is common in persons older than 80 years of age and is associated with cognitive decline and increased likelihood of dementia. The MRI signature of LATE-NC has not been fully determined. In this study, the association of LATE-NC with the transverse relaxation rate, R2, was investigated in a large number of community-based older adults. Cerebral hemispheres from 738 participants of the Rush Memory and Aging Project, Religious Orders Study, and Minority Aging Research Study, were imaged ex-vivo with multi-echo spin-echo MRI and underwent detailed neuropathologic examination. Voxel-wise analysis revealed a novel spatial pattern of lower R2 for higher LATE-NC stage, controlling for other neuropathologies and demographics. This pattern was consistent with the distribution of LATE-NC in gray matter, and also involved white matter providing temporo-temporal, fronto-temporal, and temporo-basal ganglia connectivity. Furthermore, analysis at different LATE-NC stages showed that R2 imaging may capture the general progression of LATE-NC, but only when TDP-43 inclusions extend beyond the amygdala.

Cerebral amyloid angiopathy interacts with neuritic amyloid plaques to promote tau and cognitive decline

Accumulating data suggest that cerebrovascular disease contributes to Alzheimer's disease pathophysiology and progression toward dementia. Cerebral amyloid angiopathy is a form of cerebrovascular pathology that results from the build-up of β-amyloid in the vessel walls. Cerebral amyloid angiopathy commonly co-occurs with Alzheimer's disease pathology in the ageing brain and increases the risk of Alzheimer's disease dementia. In the present study, we examined whether cerebral amyloid angiopathy influences tau deposition and cognitive decline independently or synergistically with parenchymal β-amyloid burden. Secondly, we examined whether tau burden mediates the association between cerebral amyloid angiopathy and cognitive decline. We included data from autopsied subjects recruited from one of three longitudinal clinical-pathological cohort studies: the Rush Memory and Aging Project, the Religious Orders Study and the Minority Aging Research Study. Participants completed annual clinical and cognitive evaluations and underwent brain autopsy. Cerebral amyloid angiopathy pathology was rated as none, mild, moderate or severe. Bielschowsky silver stain was used to visualize neuritic β-amyloid plaques and neurofibrillary tangles. We used linear regression and linear mixed models to test independent versus interactive associations of cerebral amyloid angiopathy and neuritic plaque burden with tau burden and longitudinal cognitive decline, respectively. We used causal mediation models to examine whether tau mediates the association between cerebral amyloid angiopathy and cognitive decline. The study sample included 1722 autopsied subjects (age at baseline = 80.2 ± 7.1 years; age at death = 89.5 ± 6.7 years; 68% females). Cerebral amyloid angiopathy interacted with neuritic plaques to accelerate tau burden and cognitive decline. Specifically, those with more severe cerebral amyloid angiopathy pathology and higher levels of neuritic plaque burden had greater tau burden and faster cognitive decline. We also found that tau mediated the association between cerebral amyloid angiopathy and cognitive decline among participants with higher neuritic plaque burden. In summary, more severe levels of cerebral amyloid angiopathy and higher parenchymal β-amyloid burden interacted to promote cognitive decline indirectly via tau deposition. These results highlight the dynamic interplay between cerebral amyloid angiopathy and Alzheimer's disease pathology in accelerating progression toward dementia. These findings have implications for Alzheimer's disease clinical trials and therapeutic development.

Genome-wide association study of brain arteriolosclerosis

Brain arteriolosclerosis (B-ASC) is characterized by pathologically altered brain parenchymal arterioles. B-ASC is associated with cognitive impairment and increased likelihood of clinical dementia. To date, no study has been conducted on genome-wide genetic risk of autopsy-proven B-ASC. We performed a genome-wide association study (GWAS) of the B-ASC phenotype using multiple independent aged neuropathologic cohorts. Included in the study were participants with B-ASC autopsy and genotype data available from the NACC, ROSMAP, ADNI, and ACT data sets. Initial Stage 1 GWAS (n = 3382) and Stage 2 mega-analysis (n = 4569) were performed using data from the two largest cohorts (NACC and ROSMAP). Replication of top variants and additional Stage 3 mega-analysis were performed incorporating two smaller cohorts (ADNI and ACT). Lead variants in the top two loci in the Stage 2 mega-analysis (rs7902929, p = 1.8 × 10 - 7 ; rs2603462, p = 4 × 10 - 7 ) were significant in the ADNI cohort (rs7902929, p = 0.012 ; rs2603462, p =0.012 ). The rs2603462 lead variant colocalized with ELOVL4 expression in the cerebellum (posterior probability = 90.1%). Suggestive associations were also found near SORCS1 and SORCS3. We thus identified putative loci associated with B-ASC risk, but additional replication is needed.

The Boston criteria version 2.0 for cerebral amyloid angiopathy: a multicentre, retrospective, MRI-neuropathology diagnostic accuracy study

BACKGROUND

Cerebral amyloid angiopathy (CAA) is an age-related small vessel disease, characterised pathologically by progressive deposition of amyloid β in the cerebrovascular wall. The Boston criteria are used worldwide for the in-vivo diagnosis of CAA but have not been updated since 2010, before the emergence of additional MRI markers. We report an international collaborative study aiming to update and externally validate the Boston diagnostic criteria across the full spectrum of clinical CAA presentations.

METHODS

In this multicentre, hospital-based, retrospective, MRI and neuropathology diagnostic accuracy study, we did a retrospective analysis of clinical, radiological, and histopathological data available to sites participating in the International CAA Association to formulate updated Boston criteria and establish their diagnostic accuracy across different populations and clinical presentations. Ten North American and European academic medical centres identified patients aged 50 years and older with potential CAA-related clinical presentations (ie, spontaneous intracerebral haemorrhage, cognitive impairment, or transient focal neurological episodes), available brain MRI, and histopathological assessment for CAA diagnosis. MRI scans were centrally rated at Massachusetts General Hospital (Boston, MA, USA) for haemorrhagic and non-haemorrhagic CAA markers, and brain tissue samples were rated by neuropathologists at the contributing sites. We derived the Boston criteria version 2.0 (v2.0) by selecting MRI features to optimise diagnostic specificity and sensitivity in a prespecified derivation cohort (Boston cases 1994-2012, n=159), then externally validated the criteria in a prespecified temporal validation cohort (Boston cases 2012-18, n=59) and a geographical validation cohort (non-Boston cases 2004-18; n=123), comparing accuracy of the new criteria to the currently used modified Boston criteria with histopathological assessment of CAA as the diagnostic standard. We also assessed performance of the v2.0 criteria in patients across all cohorts who had the diagnostic gold standard of brain autopsy.

FINDINGS

The study protocol was finalised on Jan 15, 2017, patient identification was completed on Dec 31, 2018, and imaging analyses were completed on Sept 30, 2019. Of 401 potentially eligible patients presenting to Massachusetts General Hospital, 218 were eligible to be included in the analysis; of 160 patient datasets from other centres, 123 were included. Using the derivation cohort, we derived provisional criteria for probable CAA requiring the presence of at least two strictly lobar haemorrhagic lesions (ie, intracerebral haemorrhages, cerebral microbleeds, or foci of cortical superficial siderosis) or at least one strictly lobar haemorrhagic lesion and at least one white matter characteristic (ie, severe visible perivascular spaces in centrum semiovale or white matter hyperintensities in a multispot pattern). The sensitivity and specificity of these criteria were 74·8% (95% CI 65·4-82·7) and 84·6% (71·9-93·1) in the derivation cohort, 92·5% (79·6-98·4) and 89·5% (66·9-98·7) in the temporal validation cohort, 80·2% (70·8-87·6) and 81·5% (61·9-93·7) in the geographical validation cohort, and 74·5% (65·4-82·4) and 95·0% (83·1-99·4) in all patients who had autopsy as the diagnostic standard. The area under the receiver operating characteristic curve (AUC) was 0·797 (0·732-0·861) in the derivation cohort, 0·910 (0·828-0·992) in the temporal validation cohort, 0·808 (0·724-0·893) in the geographical validation cohort, and 0·848 (0·794-0·901) in patients who had autopsy as the diagnostic standard. The v2.0 Boston criteria for probable CAA had superior accuracy to the current Boston criteria (sensitivity 64·5% [54·9-73·4]; specificity 95·0% [83·1-99·4]; AUC 0·798 [0·741-0854]; p=0·0005 for comparison of AUC) across all individuals who had autopsy as the diagnostic standard.

INTERPRETATION

The Boston criteria v2.0 incorporate emerging MRI markers of CAA to enhance sensitivity without compromising their specificity in our cohorts of patients aged 50 years and older presenting with spontaneous intracerebral haemorrhage, cognitive impairment, or transient focal neurological episodes. Future studies will be needed to determine generalisability of the v.2.0 criteria across the full range of patients and clinical presentations.

FUNDING

US National Institutes of Health (R01 AG26484).

Sex differences in the genetic architecture of cognitive resilience to Alzheimer's disease

Approximately 30% of elderly adults are cognitively unimpaired at time of death despite the presence of Alzheimer's disease neuropathology at autopsy. Studying individuals who are resilient to the cognitive consequences of Alzheimer's disease neuropathology may uncover novel therapeutic targets to treat Alzheimer's disease. It is well established that there are sex differences in response to Alzheimer's disease pathology, and growing evidence suggests that genetic factors may contribute to these differences. Taken together, we sought to elucidate sex-specific genetic drivers of resilience. We extended our recent large scale genomic analysis of resilience in which we harmonized cognitive data across four cohorts of cognitive ageing, in vivo amyloid PET across two cohorts, and autopsy measures of amyloid neuritic plaque burden across two cohorts. These data were leveraged to build robust, continuous resilience phenotypes. With these phenotypes, we performed sex-stratified [n (males) = 2093, n (females) = 2931] and sex-interaction [n (both sexes) = 5024] genome-wide association studies (GWAS), gene and pathway-based tests, and genetic correlation analyses to clarify the variants, genes and molecular pathways that relate to resilience in a sex-specific manner. Estimated among cognitively normal individuals of both sexes, resilience was 20-25% heritable, and when estimated in either sex among cognitively normal individuals, resilience was 15-44% heritable. In our GWAS, we identified a female-specific locus on chromosome 10 [rs827389, β (females) = 0.08, P (females) = 5.76 × 10-09, β (males) = -0.01, P(males) = 0.70, β (interaction) = 0.09, P (interaction) = 1.01 × 10-04] in which the minor allele was associated with higher resilience scores among females. This locus is located within chromatin loops that interact with promoters of genes involved in RNA processing, including GATA3. Finally, our genetic correlation analyses revealed shared genetic architecture between resilience phenotypes and other complex traits, including a female-specific association with frontotemporal dementia and male-specific associations with heart rate variability traits. We also observed opposing associations between sexes for multiple sclerosis, such that more resilient females had a lower genetic susceptibility to multiple sclerosis, and more resilient males had a higher genetic susceptibility to multiple sclerosis. Overall, we identified sex differences in the genetic architecture of resilience, identified a female-specific resilience locus and highlighted numerous sex-specific molecular pathways that may underly resilience to Alzheimer's disease pathology. This study illustrates the need to conduct sex-aware genomic analyses to identify novel targets that are unidentified in sex-agnostic models. Our findings support the theory that the most successful treatment for an individual with Alzheimer's disease may be personalized based on their biological sex and genetic context.

The unique effect of TDP-43 on hippocampal subfield morphometry and cognition

•We explored postmortem TDP-43 burden and antemortem hippocampal surface deformation. •TDP-43 was uniquely associated with inward deformation in the hippocampus. •Deformation patterns account for co-existing disease showing TDP-43′s unique effect. •Deformation was significantly correlated with cognition scores.

Adherence to MIND Diet, Genetic Susceptibility, and Incident Dementia in Three US Cohorts

Adherence to Mediterranean-DASH Diet Intervention for Neurodegenerative Delay (MIND) may lower the risk of dementia by impacting immunity and cholesterol, which are pathways also implicated by genome-wide association studies of Alzheimer’s Dementia (AD). We examined whether adherence to the MIND diet could modify the association of genetic risk for AD with incident dementia. We used three ongoing US cohorts: Chicago Health and Aging Project (CHAP, n = 2449), Rush Memory and Aging Project (MAP, n = 725), and Women’s Health Initiative Memory Study (WHIMS, n = 5308). Diagnosis of dementia was based on clinical neurological examination and standardized criteria. Repeated measures of global cognitive function were available in MAP and CHAP. Self-reported adherence to MIND was estimated using food-frequency questionnaires. Global and pathway-specific genetic scores (GS) for AD were derived. Cox proportional hazard, logistic regression, and mixed models were used to examine associations of MIND, GS, and GS-MIND interactions with incident dementia and cognitive decline. Higher adherence to MIND and lower GS were associated with a lower risk of dementia in MAP and WHIMS and a slower rate of cognitive decline in MAP (p < 0.05). MIND or GS were not associated with incident dementia or cognitive decline in CHAP. No gene−diet interaction was replicated across cohorts. Genetic risk and MIND adherence are independently associated with dementia among older US men and women.

Frequency of LATE neuropathologic change across the spectrum of Alzheimer's disease neuropathology: combined data from 13 community-based or population-based autopsy cohorts

Limbic-predominant age-related TDP-43 encephalopathy neuropathologic change (LATE-NC) and Alzheimer's disease neuropathologic change (ADNC) are each associated with substantial cognitive impairment in aging populations. However, the prevalence of LATE-NC across the full range of ADNC remains uncertain. To address this knowledge gap, neuropathologic, genetic, and clinical data were compiled from 13 high-quality community- and population-based longitudinal studies. Participants were recruited from United States (8 cohorts, including one focusing on Japanese-American men), United Kingdom (2 cohorts), Brazil, Austria, and Finland. The total number of participants included was 6196, and the average age of death was 88.1 years. Not all data were available on each individual and there were differences between the cohorts in study designs and the amount of missing data. Among those with known cognitive status before death (n = 5665), 43.0% were cognitively normal, 14.9% had MCI, and 42.4% had dementia-broadly consistent with epidemiologic data in this age group. Approximately 99% of participants (n = 6125) had available CERAD neuritic amyloid plaque score data. In this subsample, 39.4% had autopsy-confirmed LATE-NC of any stage. Among brains with "frequent" neuritic amyloid plaques, 54.9% had comorbid LATE-NC, whereas in brains with no detected neuritic amyloid plaques, 27.0% had LATE-NC. Data on LATE-NC stages were available for 3803 participants, of which 25% had LATE-NC stage > 1 (associated with cognitive impairment). In the subset of individuals with Thal Aβ phase = 0 (lacking detectable Aβ plaques), the brains with LATE-NC had relatively more severe primary age-related tauopathy (PART). A total of 3267 participants had available clinical data relevant to frontotemporal dementia (FTD), and none were given the clinical diagnosis of definite FTD nor the pathological diagnosis of frontotemporal lobar degeneration with TDP-43 inclusions (FTLD-TDP). In the 10 cohorts with detailed neurocognitive assessments proximal to death, cognition tended to be worse with LATE-NC across the full spectrum of ADNC severity. This study provided a credible estimate of the current prevalence of LATE-NC in advanced age. LATE-NC was seen in almost 40% of participants and often, but not always, coexisted with Alzheimer's disease neuropathology.

FMNL2 regulates gliovascular interactions and is associated with vascular risk factors and cerebrovascular pathology in Alzheimer's disease

Alzheimer's disease (AD) has been associated with cardiovascular and cerebrovascular risk factors (CVRFs) during middle age and later and is frequently accompanied by cerebrovascular pathology at death. An interaction between CVRFs and genetic variants might explain the pathogenesis. Genome-wide, gene by CVRF interaction analyses for AD, in 6568 patients and 8101 controls identified FMNL2 (p = 6.6 × 10-7). A significant increase in FMNL2 expression was observed in the brains of patients with brain infarcts and AD pathology and was associated with amyloid and phosphorylated tau deposition. FMNL2 was also prominent in astroglia in AD among those with cerebrovascular pathology. Amyloid toxicity in zebrafish increased fmnl2a expression in astroglia with detachment of astroglial end feet from blood vessels. Knockdown of fmnl2a prevented gliovascular remodeling, reduced microglial activity and enhanced amyloidosis. APP/PS1dE9 AD mice also displayed increased Fmnl2 expression and reduced the gliovascular contacts independent of the gliotic response. Based on this work, we propose that FMNL2 regulates pathology-dependent plasticity of the blood-brain-barrier by controlling gliovascular interactions and stimulating the clearance of extracellular aggregates. Therefore, in AD cerebrovascular risk factors promote cerebrovascular pathology which in turn, interacts with FMNL2 altering the normal astroglial-vascular mechanisms underlying the clearance of amyloid and tau increasing their deposition in brain.

Genetic Evidence Supporting a Causal Role of Depression in Alzheimer's Disease

BACKGROUND

Depression has been associated with a higher risk of Alzheimer's disease (AD) in several prospective studies; however, mechanisms underlying this association remain unclear.

METHODS

We examined genetic correlation between depression and AD using linkage disequilibrium score regression. We then tested for evidence of causality between depression and AD using Mendelian randomization and genome-wide association study results. Subsequently, cis and trans quantitative trait locus analyses for the depression genome-wide association study signals were performed to resolve the genetic signals to specific DNA methylation sites, brain transcripts, and proteins. These transcripts and proteins were then examined for associations with AD and its endophenotypes. Finally, the associations between depression polygenic risk score and AD endophenotypes were examined.

RESULTS

We detected a significant genetic correlation between depression and AD, suggesting that they have a shared genetic basis. Furthermore, we found that depression had a causal role in AD through Mendelian randomization but did not find evidence for a causal role of AD on depression. Moreover, we identified 75 brain transcripts and 28 brain proteins regulated by the depression genome-wide association study signals through quantitative trait locus analyses. Of these, 46 transcripts and seven proteins were associated with rates of cognitive decline over time, AD pathologies, and AD diagnosis in two separate cohorts, thus implicating them in AD. In addition, we found that a higher depression polygenic risk score was associated with a faster decline of episodic memory over time.

CONCLUSIONS

Depression appears to have a causal role in AD, and this causal relationship is likely driven, in part, by the 53 brain transcripts and proteins identified in this study.

Vascular pathology and pathogenesis of cognitive impairment and dementia in older adults

It is well recognized that brains of older people often harbor cerebrovascular disease pathology including vessel disease and vascular-related tissue injuries and that this is associated with vascular cognitive impairment and contributes to dementia. Here we review vascular pathologies, cognitive impairment, and dementia. We highlight the importance of mixed co-morbid AD/non-AD neurodegenerative and vascular pathology that has been collected in multiple clinical pathologic studies, especially in community-based studies. We also provide an update of vascular pathologies from the Rush Memory and Aging Project and Religious Orders Study cohorts with special emphasis on the differences across age in persons with and without dementia. Finally, we discuss neuropathological perspectives on the interpretation of clinical-pathological studies and emerging data in community-based studies.