Citations

Abstract Background Respiration has traditionally been considered a source of artifact in functional MRI (fMRI) due to chest motion. However, the respiratory cycle also induces changes in local oxygen concentration, resulting in fluctuations in the fMRI signal. These breathing‐triggered signals (BTS) may reflect underlying oxygen metabolism. This preliminary study developed a method to extract BTS from resting‐state BOLD fMRI and examined differences between healthy and mild cognitive impairment (MCI) groups. Method MRI scans were conducted under IRB approval on a compact 3T MRI system. Participants included two groups of 18 healthy volunteers (42.6±16.0 years) and 12 MCI patients (70.9±7.3 years). Each MRI scan included T 1 ‐weighted anatomy imaging and multi‐echo resting‐state fMRI acquisitions. The preprocessing pipeline was implemented by AFNI and FreeSurfer. Figure 1 illustrates the workflow for extracting and averaging fMRI data based on respiratory or cardiac cycle windows. As depicted in Figure 2(c,d), the mean fMRI signals corresponding to the breathing or cardiac cycles were modeled using a low‐order Fourier series to assess their amplitudes. A linear mixed‐effects model was employed to examine the effects of group and breathing cycle period, using MATLAB's ‘fitlme’ function with the formula: BTS ∼ Period + Group. Result As shown in Figure 2(e,f), breathing‐triggered BOLD signals were prominent, while cardiac‐driven BOLD signals were rarely observed. Figure 2(g) shows that global BTSs in the healthy group exhibited a linear relationship with the breathing cycle period, persisting even after artifact correction (RETROICOR for respiration and cardiac cycles and RVT). Figure 3 highlights significant regional differences between groups, particularly in the hippocampus and thalamus ( p < 0.05, uncorrected), where BTS amplitudes were greater in the MCI group. Potentially, the detected BTS could provide some insights into the coupling between respiration and cerebral oxygen metabolism and potentially serve as an imaging biomarker to assess brain health. However, due to the limited number of samples, these findings should be interpreted with caution, and further analysis is needed. Conclusion This preliminary study suggests that breathing‐triggered signals in resting‐state BOLD fMRI have the potential to serve as a noninvasive biomarker for early detection and monitoring of neurodegenerative conditions such as MCI.

Abstract Background Sensitive, accessible biomarkers of the pathologies underlying Alzheimer's disease and related dementias (ADRD) are critical for accurate diagnosis, deeper understanding of disease mechanisms, and development of new therapies with validated target engagement. The retina is connected to the brain via the optic nerve, which may facilitate the transmission and spread of amyloid beta (Aβ) and tau species. In postmortem studies, retinal Aβ deposits have been associated with neuritic Aβ‐plaque and neurofibrillary tangle burden, particularly in the entorhinal and temporal cortices. The goal of the current study was to evaluate associations between retinal perivascular amyloid and cognition, as well as to explore effect modification by hippocampal volumetry. Method Participants, aged ≥40 years, underwent retinal imaging, brain MRI, FDG‐PET, and a comprehensive neuropsychological assessment. Retinal amyloid imaging was conducted following curcumin ingestion and pupil dilation using a confocal scanning laser ophthalmoscope. Perivascular Aβ plaque counts were quantified in the superotemporal peripheral region following manual identification and tracking of retinal arteries and veins. Associations between retinal perivascular Aβ plaque counts with cognitive domains were evaluated using linear regression models adjusted for age, sex, and estimated premorbid functioning. Where significant associations were detected ( p ‐value<0.05), effect modification by hippocampal volumetry was examined with additional adjustment for intracranial volume. Result The sample included 26 participants (mean age 65±7 years, 50% female). Higher amyloid plaque counts in the perivascular secondary small and tertiary branches and in the periarteriolar tertiary branch were associated with poorer verbal and visual memory (Table 1). Significant interactions were observed between amyloid plaque count in the perivascular secondary small branch (β(95% Confidence Interval) = 0.397(0.037‐0.756), p = 0.033) and periarteriolar tertiary branch (β(95% Confidence Interval) = 0.756(0.165–1.346), p = 0.017) with hippocampal volumetry for visual memory. Conclusion Our pilot study provides preliminary evidence that perivascular Aβ accumulation in smaller vessels of the superotemporal retina may be a marker of memory impairment that may interact synergistically with hippocampal atrophy. Longitudinal studies consisting of multimodal ophthalmic assessments, brain imaging, ADRD biofluid markers, and cognitive testing will be necessary to capture the temporal sequence of retinal pathological changes and their associations with those in the brain.

ABSTRACT Aims To investigate whether the association between the nitrite‐generating capacity of the subgingival microbiome and early cardiometabolic risk biomarkers varies by dietary nitrate intake. Materials and Methods Cross‐sectional data from 668 participants (mean age 31 ± 9 years, 73% women) were analysed. Dietary nitrate intake was calculated from food frequency questionnaires. Subgingival 16S rRNA sequencing (Illumina, MiSeq) and PICRUSt2 estimated microbial genes. The Microbiome‐Induced Nitric Oxide Enrichment Score (MINES) was calculated as a ratio of microbial gene abundances representing enhanced net capacity for NO generation. Adjusted multivariable linear models regressed cardiometabolic risk biomarkers (HbA1c, glucose, insulin, insulin resistance (HOMA‐IR), blood pressure) on nitrate intake and MINES together with a MINES × nitrate intake interaction term. Results Mean nitrate intake was 190 ± 171 mg/day. Significant interactions of MINES and nitrate intake were observed for insulin and HOMA‐IR ( p < 0.05). Among participants with a low MINES, higher nitrate intake was associated with lower HOMA‐IR (1.2 [1.1–1.4] vs. 1.5 [1.3–1.6]; p = 0.002), but levels were similar in those with high MINES ( p = 0.84). Conclusions A biomarker of higher microbial NO‐generating capacity in subgingival plaque is associated with lower insulin and insulin resistance among individuals with lower dietary nitrate intake. Future trials evaluating the cardiometabolic benefits of nitrate‐rich diets should incorporate measures of the entire oral microbiome.

Abstract Background Prospective investigations on blood biomarkers for Alzheimer's disease and related‐dementias (ADRDs) and cognitive impairment provide important insights into their clinical utility in early disease diagnosis and risk stratification, but have been primarily limited to AD pathologies (e.g. amyloid‐beta and hyperphosphorylated‐tau aggregation). Studies of biomarkers reflecting other pathogenic processes that contribute to ADRDs, especially in community‐based cohorts, are lacking. We examined associations of blood biomarkers reflecting glial and neuronal dysfunction and neuroinflammation, including soluble cluster of differentiation‐14 (sCD14), chitinase‐3‐like protein‐1 (YKL‐40), glial‐fibrillary acidic protein (GFAP), neurofilament‐light chain (NfL), total‐Tau, and Ubiquitin C‐terminal hydrolase L1 (UCH‐L1) with cognitive decline and incident dementia in ARIC study participants. Methods Blood biomarkers were measured in 1,864 ARIC Visit 3 (1993‐1995) participants using the Meso Scale Discovery assay (YKL‐40), the Quanterix Simoa Neurology 4‐Plex assay (total‐Tau, NfL, GFAP, UCH‐L1), and a commercial ELISA assay (sCD14, R&D Systems); global cognition z‐scores were derived from three cognitive tests (measuring memory, language, and executive function) administered up to six times over 25 years, and incident dementia cases were ascertained via in‐person cognitive assessments (expert‐adjudicated), informant‐based interviews, and hospitalization and death records through 2018. We used shared parameter models to simultaneously fit linear mixed‐effect models and proportional hazard models to estimate 25‐year cognitive decline and dementia rates separately for each biomarker (log‐base2‐transformed), adjusting for covariates (Table). Results Among 1,864 participants (mean±SD age:63±4.5 years, 60% female, 49% self‐reported Black), 27% developed dementia. Higher levels of each biomarker were associated with faster cognitive decline. All but UCH‐L1 were associated with elevated dementia risk (Table). For example, one standard deviation (SD) higher log‐base2 YKL‐40 was associated with ‐0.10 SD steeper 25‐year cognitive decline (95%CI:‐0.15,‐0.04) and 59% higher dementia hazard (hazard ratio (HR):1.59 (95%CI:1.20,2.10); likewise, sCD14 was associated with an additional cognitive decline of ‐0.06 (95%CI:‐0.11,‐0.01) and 38% higher dementia hazard (HR:1.38 (95%CI:1.08,1.76)). Conclusions Blood biomarkers reflecting neuropathological processes, including microglial activation, astrocytic reactivity, and neuronal degeneration, were associated with faster cognitive decline and increased dementia risk, suggesting that they may aid in risk stratification and intervention strategies for ADRDs. Future analyses will examine whether these associations differ by race and APOE‐ε4 s tatus.

Abstract Background Primary progressive apraxia of speech (PPAOS) is a frontotemporal lobar degeneration spectrum disorder characterized by progressive speech motor planning/programming decline. Patients often develop neurological symptoms, frequently evolving into progressive supranuclear palsy (PSP)/corticobasal syndrome (CBS) overlap syndromes. Requests for information about disease progression and causes of death are common amongst our clinical and research encounters; however, empiric evidence to guide these discussions is lacking. Understanding causes of death may enhance counseling and support targeted interventions to delay fatal outcomes. This study aimed to describe causes of death in PPAOS. Methods Data from 29 deceased PPAOS patients (16 males) seen in research studies (July 2010–May 2023) were reviewed. Causes of death were established from medical charts and family reports. Fifteen had prosodic and 12 had phonetic‐predominant PPAOS; two had no clear predominance. Median age at onset was 67.08 years, disease duration 9.78 years, and age at death 76.25 years. 28 patients were white and one was Asian Indian. Results Overall, fifteen (52%) patients died from overall deterioration (cachexia/dehydration), nine (31%) from aspiration pneumonia, and the remainder from falls (10%), asphyxiation (3%), or medical aid in dying (3%). There was no clear association with AOS subtype and cause of death. Conclusions Most deaths in PPAOS resulted from systemic failure or dysphagia‐related complications. Half of the patients died without a clear precipitating event, described by family members as “shutting down,” similar to other prior studies that have shown central nervous system deterioration associated with dementia as cause of death. Aspiration pneumonia caused 34% of deaths, highlighting the need for early swallowing management, including assessments, dietary adjustments, and caregiver education. Falls underscore the importance of addressing balance and motor impairments through proactive prevention strategies. Other factors, such as access to healthcare and medical and psychiatric comorbidities were not analyzed but may influence outcomes. Future research should validate these findings in larger, diverse cohorts and compare outcomes to motor‐onset presentations of PSP and CBS. A comprehensive, multidisciplinary approach addressing motor speech impairments, dysphagia, and fall risks is essential to improve care and potentially extend survival for patients with PPAOS.

Abstract Background Trials in Lewy body dementia (LBD) rely on scales and measurements created for Alzheimer’s disease and Parkinson’s disease. Industry and regulatory authority stakeholders and LBD triallists have recognised the absence of an LBD‐specific scale as critical unmet need in the drug development pipeline. Heterogeneity in LBD trials design, particularly concerning outcome measures, precludes effective evidence synthesis and data harmonisation. We describe the development of the Lewy Body Dementia‐Domain Rating Scale (LBD‐DRS) and a proposed roadmap for adoption and validation. Method Led by a core working group and steering committee, a three‐round Delphi survey process was used to establish consensus around the conceptual framework and preliminary content of the LBD‐DRS among invited LBD researchers and clinicians. “Consensus” was established when ≥75% of respondents concurred on any survey statement or questions. Result Consensus around the need for an LBD‐specific scale, specifically for use in early LBD, was established. After feedback was received for two early versions of LBD, a third version of LBD‐DRS has been further developed. This third version, and the results of the second Delphi survey round will be presented. A pragmatic approach, favouring an inclusive scoring approach for symptoms has been adopted, recognising that further iterations will be required once field data becomes available. Conclusion After consensus on the conceptual framework and preliminary content is established, the authors will consult with a broader range of stakeholders, including people living with LBD and their care partners, will be required to further develop LBD‐DRS. Engagement with regulatory bodies and the pharmaceutical industry will guide further development before validation studies are pursued.

Abstract Background Alzheimer’s disease (AD) is a multifactorial disease often with mixed pathologies. As such, drugs targeting multiple pathological processes simultaneously could have synergistic therapeutic effects. The histone acetylation homeostasis is greatly impaired in AD, and histone deacetylase (HDAC) inhibitors have been known to alleviate AD‐relevant pathologies in various animal models. In addition, Wnt/β‐catenin signaling is compromised in AD, and restoring Wnt/β‐catenin signaling is an attractive therapeutic strategy for AD treatment. CI‐994 is a class I HDAC inhibitor containing N‐(2‐aminophenyl)‐benzamide. Our recent studies indicate that CI‐994 is also an activator of Wnt/β‐catenin signaling by stabilizing Wnt co‐receptor LRP6. Method We use CI‐994 as a scaffold to develop novel potent dual modulators for class I HDAC inhibition and Wnt/β‐catenin signaling activation, and then determine the therapeutic potential of the lead compound W2A‐28 in AD patient‐specific iPSC‐derived cerebral organoids. Result W2A‐28 inhibits class I HDAC1, 2 and 3 activities with IC 50 values of 512 nM, 675 nM and 217 nM, respectively, with no inhibitory activities on other HDACs and Sirtuin family members. Furthermore, W2A‐28 greatly increases Wnt reporter activity with an EC 50 value of 1.61 µM in Wnt‐3A‐expressing HEK293 cells. As expected, activation of Wnt/β‐catenin signaling by W2A‐28 is associated with elevated Wnt co‐receptor LRP6 protein level by reducing LRP6 degradation. Importantly, W2A‐28 displays excellent aqueous solubility and microsomal stability. Further, W2A‐28 shows high permeability with no active efflux in MDR1‐MDCKII permeability assays and is not a P‐gp substrate. Finally, W2A‐28 significantly reduces Aβ40 and Aβ42 levels and suppresses tau phosphorylation in AD patient‐specific iPSC‐derived cerebral organoids carrying APOE4. Conclusion Our studies suggest that W2A‐28 is a potential drug candidate for the treatment of AD.

Abstract Background Dementia with Lewy bodies (DLB) is a prevalent form of dementia associated with neuronal alpha‐synuclein aggregates (Lewy bodies). Symptoms include cognitive impairment, fluctuations, neuropsychiatric features including psychosis, sleep disorders, and dysautonomia. DLB is the most expensive form of dementia, and there are currently no treatments approved by the US FDA. Given the advent of sensitive and specific in vivo biomarkers for synuclein aggregation, drug developers are increasingly interested in DLB. FDA instituted Patient‐Focused Drug Development (PFDD) meetings in 2012 with the purpose of ensuring that patients’ experiences, perspectives, needs, and preferences are captured and meaningfully incorporated into drug development and evaluation. Method In October 2024, the Lewy Body Dementia Association (LBDA) and the Alzheimer’s Association (ALZ) co‐hosted an externally‐led PFDD (EL‐PFDD) meeting on DLB. Thirty days before the event, LBDA solicited public comment on the lived experience of DLB, the current state of treatment, and what people with DLB value in potential future therapies. During the live meeting, people with DLB, care partners and family members described their experiences and responded to live polling questions. Result The EL‐PFDD was attended by 347 people with DLB and care partners, drug developers (both industry and academic), FDA staff, and NIH staff. Preliminary analysis of the discussion content and survey responses shows several themes emerging from the meeting. The most bothersome and impactful symptoms varied over the course of the disease, but included cognitive impairment and fluctuations, neuropsychiatric symptoms, and sleepiness. Concerns for the future included progressive decline in cognition, changes in behavior/mood, and cost of care. Limitations to current treatments included lack of FDA‐approved medications, and side effects and lack of efficacy associated with “off label” medications. Priorities for future treatments included symptomatic treatments that do not worsen other DLB symptoms, slowing disease progression, accessibility/insurance coverage, and avoiding side effects. Conclusion The EL‐PFDD on DLB provided valuable information for drug developers and regulators to understand the lived experience of people with DLB and care partners. The results will be documented in a “Voice of the Patient” report that will be hosted at www.lbda.org/el‐pfdd .

Abstract Background Even among cognitively unimpaired (CU) older adults, specific patterns of neuropsychological performance impart differential risk for progression to Alzheimer's disease and related dementias (ADRD). Early identification in the prodromal phase may inform early intervention efforts. We used a data‐driven approach to classify neuropsychological phenotypes within CU older adults from the Atherosclerosis Risk in Communities (ARIC) study and tested for differences in ADRD and cerebrovascular outcomes. Method Participants included 4737 CU (via a previously published algorithm plus consensus diagnosis protocol) older adults (mean age=75.1 years, 60.8% female, 23.1% Black) with neuropsychological data from Visit 5 (2011‐2013) of the ARIC study. Latent profile analysis was leveraged to identify unique cognitive phenotypes using 10 demographically adjusted (age, sex/gender, education, race‐center, WRAT Reading) neuropsychological z‐scores. Cognitive phenotypes were then compared on demographics, depressive symptoms, and vascular risk factors (VRFs). In a subset with available neuroimaging and biofluid data ( n range=1102‐1678), white matter hyperintensity (WMH) and bilateral hippocampal (HV) volumes normalized for intracranial volume and plasma biomarkers (i.e., Aβ42/40, ptau181, NfL, and GFAP) were examined by phenotype. Phenotype comparisons adjusted for demographic variables, VRFs, and an indicator of kidney function (i.e., eGFR‐creatinine) for plasma biomarkers. We applied Tukey adjustment for pairwise comparisons. Result A 6‐class solution of cognitive phenotypes emerged as the best fitting model: Average Overall (28%), Low Overall/Very Low Memory (7%), Average Overall/Super Memory (11%), Subtle Low Overall/Low Executive (22%), Subtle Low Executive/High Memory (13%), and Average Overall/Low Memory (19%; Figure 1). Phenotypes differed on education, race, and word reading, despite prior adjustments for these variables when creating the neuropsychological z‐scores (Table 1). Additionally, phenotypes differed on depressive symptoms, VRFs, WMH, HV, Aβ42/40, and ptau181 (all p s < .05). The Subtle Low Overall/Low Executive group had the highest WMH volumes, the Subtle Low Executive/High Memory group had the lowest Aβ42/40, and the Low Overall/Very Low Memory group had the lowest HV and highest levels of plasma ptau181 (Table 2). Conclusion Cognitive heterogeneity is observed even among CU older adults, with lower executive performance associated with cerebrovascular changes and lower memory associated with certain AD‐related changes, possibly indicating risk for cognitive progression through distinct pathways.

Abstract Coarsening Visium HD resolution from 8 to 64 µ m can flip cell-type co-localization from negative to positive ( r = −0.12 → +0.80 ), yet many widely used compositional deconvolution workflows require coarsening or subsampling at million-bin scale. Here we introduce FlashDeconv, which combines leverage-score importance sampling with sparse spatial regularization to achieve competitive benchmark accuracy while processing 1.6 million bins in 153 seconds on commodity hardware. Systematic multi-resolution analysis of Visium HD mouse intestine reveals a tissue-specific resolution horizon (8–16 µ m)—the scale at which this sign inversion occurs—validated by Xenium ground truth. Below this horizon, FlashDeconv provides, to our knowledge, the first sequencing-based quantification of Tuft cell chemosensory niches (15.3-fold stem cell enrichment). In a 1.6-million-bin human colorectal cancer cohort, FlashDeconv uncovers neutrophil inflammatory microdomains co-localized with immunoregulatory dendritic cells (mRegDC) at the tumor–stroma interface—spatial niches largely missed by discrete-label summaries, with RCTD doublet mode labeling only 2.3% of hotspot bins as neutrophil singlets.