Basic Science and Pathogenesis.

Background: In cerebral amyloid angiopathy, amyloid beta accumulates within the walls of blood vessels and contributes to impaired vascular integrity and function. In this work, we observe that tau protein similarly builds up along blood vessels in Alzheimer's disease brain.

Method: We obtained frozen inferior temporal cortex from the Massachusetts Alzheimer's Disease Research Center from n = 7 neuropathological confirmed Alzheimer's disease donors and n = 6 normal aging controls.

Basic Science and Pathogenesis.

Background: Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by the deposition of amyloid-beta and hyperphosphorylated tau (P-tau) proteins in the brain. P-tau accumulates in neurons and is strongly associated with AD severity and affected brain regions. However, only a subset of neurons in AD exhibit tau pathology.

Basic Science and Pathogenesis.

Background: Currently, it is unclear to what extent late-onset Alzheimer's disease (AD) risk variants contribute to early-onset AD (EOAD). One method to clarify the contribution of late-onset AD genetic risk to EOAD is to investigate the association of AD polygenic risk scores (PRS) with EOAD. We hypothesize that in the Longitudinal Early-Onset Alzheimer's Disease Study (LEADS), EOAD participants will have greater PRS than early-onset amyloid-negative cognitively-impaired participants (EOnonAD) and controls, and investigate the association of AD PRS with age of disease onset (AoO) and cognitive performance.

Clinical Manifestations.

Background: This study responds to the urgent need for automated and reliable methods to detect cognitive impairments on a large scale. It leverages natural language processing (NLP) techniques to predict dementia and mild cognitive impairment (MCI) using clinical notes from electronic health records (EHR).

Method: Our study used an EHR dataset from Massachusetts General Brigham, which included clinical notes from a 2-year period (2017-2018) covering 12 types of patient encounters.

Clinical Manifestations.

Background: Widespread cognitive impairments have previously been documented in Early-Onset Alzheimer's Disease (EOAD) relative to cognitively normal (CN) same-aged peers or those with cognitive impairment without amyloid pathology (Early-Onset non-Alzheimer's Disease; EOnonAD; Hammers et al., 2023). Prior preliminary work has similarly observed worse cognitive performance being associated with earlier ages in EOAD participants enrolled in the Longitudinal Early-Onset Alzheimer's Disease Study (LEADS; Apostolova et al.

Clinical Manifestations.

Background: Early-Onset Alzheimer's Disease (EOAD) is a rare condition that affects only 5% of patients with Alzheimer's Disease (AD). At present, only basic information is known about the impact of AD risk variants on EOAD, and the effects of more subtle genetic contributions to cognitive decline have yet to be investigated. Genetic variants for brain derived neurotrophic factor (BDNF) and catechol-O-methyltransferase (COMT) have both been implicated in cognitive change (Fiocco et al.

Clinical Manifestations.

Background: "SuperAgers" (SA) are older adults who perform significantly better than their peers and comparable to young adults on objective memory measures. Longitudinal studies show that many do not maintain their SA status over time. The fluctuation in SA stability may reflect changes in executive functioning, hypothesized to contribute to variance of episodic memory scores in SA.

Greater baseline cortical atrophy in the dorsal attention network predicts faster clinical decline in Posterior Cortical Atrophy.

Background: Posterior Cortical Atrophy (PCA) is a clinical syndrome characterized by progressive visuospatial and visuoperceptual impairment. As the neurodegenerative disease progresses, patients lose independent functioning due to the worsening of initial symptoms and development of symptoms in other cognitive domains. The timeline of clinical progression is variable across patients, and the field currently lacks robust methods for prognostication.

Location and function of TDP-43 in platelets, alterations in neurodegenerative diseases and arising considerations for current plasma biobank protocols.

The TAR DNA Binding Protein 43 (TDP-43) has been implicated in the pathogenesis of human neurodegenerative diseases and exhibits hallmark neuropathology in amyotrophic lateral sclerosis (ALS). Here, we explore its tractability as a plasma biomarker of disease and describe its localization and possible functions in the cytosol of platelets. Novel TDP-43 immunoassays were developed on three different technical platforms and qualified for specificity, signal-to-noise ratio, detection range, variation, spike recovery and dilution linearity in human plasma samples.

Language abnormalities in Alzheimer's disease indicate reduced informativeness.

Objective: This study aims to elucidate the cognitive underpinnings of language abnormalities in Alzheimer's Disease (AD) using a computational cross-linguistic approach and ultimately enhance the understanding and diagnostic accuracy of the disease.

Methods: Computational analyses were conducted on language samples of 156 English and 50 Persian speakers, comprising both AD patients and healthy controls, to extract language indicators of AD. Furthermore, we introduced a machine learning-based metric, Language Informativeness Index (LII), to quantify empty speech.

Artificial intelligence classifies primary progressive aphasia from connected speech.

Neurodegenerative dementia syndromes, such as primary progressive aphasias (PPA), have traditionally been diagnosed based, in part, on verbal and non-verbal cognitive profiles. Debate continues about whether PPA is best divided into three variants and regarding the most distinctive linguistic features for classifying PPA variants. In this cross-sectional study, we initially harnessed the capabilities of artificial intelligence and natural language processing to perform unsupervised classification of short, connected speech samples from 78 pateints with PPA.

Multifaceted roles of APOE in Alzheimer disease.

For the past three decades, apolipoprotein E (APOE) has been known as the single greatest genetic modulator of sporadic Alzheimer disease (AD) risk, influencing both the average age of onset and the lifetime risk of developing AD. The APOEε4 allele significantly increases AD risk, whereas the ε2 allele is protective relative to the most common ε3 allele. However, large differences in effect size exist across ethnoracial groups that are likely to depend on both global genetic ancestry and local genetic ancestry, as well as gene-environment interactions.

β-Amyloid species production and tau phosphorylation in iPSC-neurons with reference to neuropathologically characterized matched donor brains.

A basic assumption underlying induced pluripotent stem cell (iPSC) models of neurodegeneration is that disease-relevant pathologies present in brain tissue are also represented in donor-matched cells differentiated from iPSCs. However, few studies have tested this hypothesis in matched iPSCs and neuropathologically characterized donated brain tissues. To address this, we assessed iPSC-neuron production of β-amyloid (Aβ) Aβ40, Aβ42, and Aβ43 in 24 iPSC lines matched to donor brains with primary neuropathologic diagnoses of sporadic AD (sAD), familial AD (fAD), control, and other neurodegenerative disorders.

Characterization of monoamine oxidase-B (MAO-B) as a biomarker of reactive astrogliosis in Alzheimer's disease and related dementias.

Reactive astrogliosis accompanies the two neuropathological hallmarks of Alzheimer's disease (AD)-Aβ plaques and neurofibrillary tangles-and parallels neurodegeneration in AD and AD-related dementias (ADRD). Thus, there is growing interest in developing imaging and fluid biomarkers of reactive astrogliosis for AD/ADRD diagnosis and prognostication. Monoamine oxidase-B (MAO-B) is emerging as a target for PET imaging radiotracers of reactive astrogliosis.

Landscape of brain myeloid cell transcriptome along the spatiotemporal progression of Alzheimer's disease reveals distinct sequential responses to Aβ and tau.

Human microglia are critically involved in Alzheimer's disease (AD) progression, as shown by genetic and molecular studies. However, their role in tau pathology progression in human brain has not been well described. Here, we characterized 32 human donors along progression of AD pathology, both in time-from early to late pathology-and in space-from entorhinal cortex (EC), inferior temporal gyrus (ITG), prefrontal cortex (PFC) to visual cortex (V2 and V1)-with biochemistry, immunohistochemistry, and single nuclei-RNA-sequencing, profiling a total of 337,512 brain myeloid cells, including microglia.

Update on modifiable risk factors for Alzheimer's disease and related dementias.

Purpose Of Review: All human beings undergo a lifelong cumulative exposure to potentially preventable adverse factors such as toxins, infections, traumatisms, and cardiovascular risk factors, collectively termed exposome. The interplay between the individual's genetics and exposome is thought to have a large impact in health outcomes such as cancer and cardiovascular disease. Likewise, a growing body of evidence is supporting the idea that preventable factors explain a sizable proportion of Alzheimer's disease and related dementia (ADRD) cases.

Using Generative Artificial Intelligence to Classify Primary Progressive Aphasia from Connected Speech.

Neurodegenerative dementia syndromes, such as Primary Progressive Aphasias (PPA), have traditionally been diagnosed based in part on verbal and nonverbal cognitive profiles. Debate continues about whether PPA is best subdivided into three variants and also regarding the most distinctive linguistic features for classifying PPA variants. In this study, we harnessed the capabilities of artificial intelligence (AI) and natural language processing (NLP) to first perform unsupervised classification of concise, connected speech samples from 78 PPA patients.

Targeting amyotrophic lateral sclerosis by neutralizing seeding-competent TDP-43 in CSF.

In amyotrophic lateral sclerosis, a disease driven by abnormal transactive response DNA-binding protein of 43 kDa aggregation, CSF may contain pathological species of transactive response DNA-binding protein of 43 kDa contributing to the propagation of pathology and neuronal toxicity. These species, released in part by degenerating neurons, would act as a template for the aggregation of physiological protein contributing to the spread of pathology in the brain and spinal cord. In this study, a robust seed amplification assay was established to assess the presence of seeding-competent transactive response DNA-binding protein of 43 kDa species in CSF of apparently sporadic amyotrophic lateral sclerosis patients.

Association of Plasma Phosphorylated Tau With the Response to Neflamapimod Treatment in Patients With Dementia With Lewy Bodies.

Background And Objectives: In a proportion of patients, dementia with Lewy bodies (DLB) is associated with Alzheimer disease (AD) copathology, which is linked to accelerated cognitive decline and more extensive cortical atrophy. The objective was to evaluate the relationship between a biomarker of AD copathology, plasma tau phosphorylated at residue 181 (ptau181), and the treatment effects of the p38α kinase inhibitor neflamapimod, which targets the cholinergic degenerative process in DLB.

Methods: The AscenD-LB study was a phase 2a, randomized (1:1), 16-week, placebo-controlled clinical trial of neflamapimod in DLB, the main results of which have been published.

Potential impact of the COVID-19 pandemic on everyday preferences for persons with cognitive impairment.

The COVID-19 pandemic and subsequent social distancing guidelines and restrictions brought on changes in the everyday experiences of older adults. It is not clear, however, to what extent the pandemic has impacted the importance of everyday preferences for persons with cognitive impairment (CI) or the proxy ratings of those preferences. The sample of this study included 27 dyads of persons with CI and their care partners.