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Cellular senescence contributes to Alzheimer’s disease (AD) pathogenesis. An open-label, proof-of-concept, phase I clinical trial of orally delivered senolytic therapy, dasatinib (D) and quercetin (Q), was conducted in early-stage symptomatic patients with AD to assess central nervous system (CNS) penetrance, safety, feasibility and efficacy. Five participants (mean age = 76 + 5 years; 40% female) completed the 12-week pilot study. D and Q levels in blood increased in all participants (12.7–73.5 ng ml −1 for D and 3.29–26.3 ng ml −1 for Q). In cerebrospinal fluid (CSF), D levels were detected in four participants (80%) ranging from 0.281 to 0.536 ml −1 with a CSF to plasma ratio of 0.422–0.919%; Q was not detected. The treatment was well-tolerated, with no early discontinuation. Secondary cognitive and neuroimaging endpoints did not significantly differ from baseline to post-treatment further supporting a favorable safety profile. CSF levels of interleukin-6 (IL-6) and glial fibrillary acidic protein (GFAP) increased ( t (4) = 3.913, P  = 0.008 and t (4) = 3.354, P  = 0.028, respectively) with trending decreases in senescence-related cytokines and chemokines, and a trend toward higher Aβ42 levels ( t (4) = −2.338, P  = 0.079). In summary, CNS penetrance of D was observed with outcomes supporting safety, tolerability and feasibility in patients with AD. Biomarker data provided mechanistic insights of senolytic effects that need to be confirmed in fully powered, placebo-controlled studies. ClinicalTrials.gov identifier: NCT04063124 . The first feasibility study of orally delivered senolytic therapy in Alzheimer’s disease reports favorable safety data and penetrance of dasatinib into the brain with a modest impact on Alzheimer’s and aging biomarkers.

A bidirectional communication exists between the brain and the gut, in which the gut microbiota influences cognitive function and vice-versa. Gut dysbiosis has been linked to several diseases, including Alzheimer's disease and related dementias (ADRD). However, the relationship between gut dysbiosis and markers of cerebral small vessel disease (cSVD), a major contributor to ADRD, is unknown. In this cross-sectional study, we examined the connection between the gut microbiome, cognitive, and neuroimaging markers of cSVD in the Framingham Heart Study (FHS). Markers of cSVD included white matter hyperintensities (WMH), peak width of skeletonized mean diffusivity (PSMD), and executive function (EF), estimated as the difference between the trail-making tests B and A. We included 972 FHS participants with MRI scans, neurocognitive measures, and stool samples and quantified the gut microbiota composition using 16S rRNA sequencing. We used multivariable association and differential abundance analyses adjusting for age, sex, BMI, and education level to estimate the association between gut microbiota and WMH, PSMD, and EF measures. Our results suggest an increased abundance of Pseudobutyrivibrio and Ruminococcus genera was associated with lower WMH and PSMD ( p values < 0.001), as well as better executive function ( p values < 0.01). In addition, in both differential and multivariable analyses, we found that the gram-negative bacterium Barnesiella intestinihominis was strongly associated with markers indicating a higher cSVD burden. Finally, functional analyses using PICRUSt implicated various KEGG pathways, including microbial quorum sensing, AMP/GMP-activated protein kinase, phenylpyruvate, and β-hydroxybutyrate production previously associated with cognitive performance and dementia. Our study provides important insights into the association between the gut microbiome and cSVD, but further studies are needed to replicate the findings.

Oral and gut microbiomes have been associated with Alzheimer's disease and related dementias (ADRD). Although the role of the gut microbiome and gut dysbiosis in ADRD has been extensively studied, research on the oral microbiome is lacking. Moreover, the synergetic contribution of oral and gut microbiomes to ADRD is unexplored. This study aimed to assess the differential patterns of oral and gut microbiomes and their synergetic effects in patients with mild cognitive impairment (MCI) compared to normal cognition (NC). Gut and saliva microbiome abundance and diversity measurements were obtained using 16S rRNA gene sequencing of stool and saliva samples from 27 participants (12 MCI, 15 NC, %F = 66.7, Age = 70.2 ± 6.4) recruited in San Antonio, Texas, USA (Table 1). The indexes Chao1, ACE, Observe, Shannon, and Simpson were computed to assess the 〈-diversity of samples. However, the ®-diversity was investigated after carrying out the principal coordinates analysis (PCoA) based on Bray-Curtis distances to visualize group separation in compositional data. We used linear discriminant effect size and differential abundant analysis to identify gut and saliva features statistically different between MCI and NC (adjusted p-value < 0.005). No differences in bacteria 〈- and ®-diversity between MCI and NC (Figure 1) were found. However, we found an increased abundance of oral pathogenic genera, including Anaeroglobus, Centipeda, Cardiobacterium, Dialister, Fretibacterium, Leptotrichia, Mycoplasma, Tannerella, and Treponema in patients with MCI (Figure 2). We also found that MCI patients have a decreased abundance of gut genera Butyricicoccus, Defluviitaleaceae, Lachnospira, Paludicola, Shuttleworthia, and Subdoligranulum. These differential abundant gut genera have been shown to harbor anti-inflammatory properties. We did not find evidence of synergetic contributions of oral and gut genera to MCI. Our results suggest that the saliva microbiome, like the gut microbiome, is disrupted as patients progress from NC to MCI. The pathogenic oral microbes we found were previously linked to periodontal and gingivitis pathogens. Further studies with larger sample sizes are needed to validate these findings.

Alterations in both oral and gut microbiomes have been associated with Alzheimer’s disease and related dementia (ADRD). While extensive research has focused on the role of gut dysbiosis in ADRD, the contribution of the oral microbiome remains relatively understudied. This study aims to evaluate distinct patterns and potential synergistic effects of oral and gut microbiomes in a cohort of predominantly Hispanic individuals with cognitive impairment (CI) and without cognitive impairment (NC). We conducted 16S rRNA gene sequencing on stool and saliva samples from 32 participants (17 CI, 15 NC; 62.5% female, mean age = 70.4 ± 6.2 years) recruited in San Antonio, Texas, USA. Differential abundance analysis evaluated taxa with significant differences between both groups. While diversity metrics showed no significant differences between CI and NC groups, differential abundance analysis revealed an increased presence of oral genera such as Dialister, Fretibacterium, and Mycoplasma in CI participants. Conversely, CI individuals exhibited a decreased abundance of gut genera, including Shuttleworthia, Holdemania, and Subdoligranulum, which are known for their anti-inflammatory properties. No evidence was found for synergistic contributions between oral and gut microbiomes in the context of CI. Our findings suggest that like the gut microbiome, the oral microbiome of CI participants undergoes significant modifications. Notably, the identified oral microbes have been previously associated with periodontal diseases and gingivitis. These results underscore the necessity for further investigations with larger sample sizes to validate our findings and elucidate the complex interplay between oral and gut microbiomes in ADRD pathogenesis.

Health tracking technologies hold promise as a tool for early detection of cognitive and functional decline. This pilot study of 5 households [  = 7 residents, mean age: 74 (5), 71% Hispanic, 14% Black] used the Oregon Center for Aging & Technology (ORCATECH) platform to evaluate the technology and acceptance of the technology over a one-year interval in South Texas. Cognitive assessments and other surveys were administered at baseline and end-of-study visits. Participants felt comfortable with the technology in their homes (86% Very Satisfactory or Satisfactory) and did not express privacy concerns (100% Very Satisfactory or Satisfactory). Health, cognition, and activity measures did not significantly change from baseline to end-of-study. Depression scores significantly improved (  = 0.034). The ORCATECH platform was an acceptable method of analyzing health and activity in a small, but diverse older population.

Background Oral and gut microbiomes have been associated with Alzheimer’s disease and related dementias (ADRD). Although the role of the gut microbiome and gut dysbiosis in ADRD has been extensively studied, research on the oral microbiome is lacking. Moreover, the synergetic contribution of oral and gut microbiomes to ADRD is unexplored. This study aimed to assess the differential patterns of oral and gut microbiomes and their synergetic effects in patients with mild cognitive impairment (MCI) compared to normal cognition (NC). Method Gut and saliva microbiome abundance and diversity measurements were obtained using 16S rRNA gene sequencing of stool and saliva samples from 27 participants (12 MCI, 15 NC, %F = 66.7, Age = 70.2 ± 6.4) recruited in San Antonio, Texas, USA (Table 1). The indexes Chao1, ACE, Observe, Shannon, and Simpson were computed to assess the 〈‐diversity of samples. However, the ®‐diversity was investigated after carrying out the principal coordinates analysis (PCoA) based on Bray‐Curtis distances to visualize group separation in compositional data. We used linear discriminant effect size and differential abundant analysis to identify gut and saliva features statistically different between MCI and NC (adjusted p‐value < 0.005). Result No differences in bacteria 〈‐ and ®‐diversity between MCI and NC (Figure 1) were found. However, we found an increased abundance of oral pathogenic genera, including Anaeroglobus, Centipeda, Cardiobacterium, Dialister, Fretibacterium, Leptotrichia, Mycoplasma, Tannerella, and Treponema in patients with MCI (Figure 2). We also found that MCI patients have a decreased abundance of gut genera Butyricicoccus, Defluviitaleaceae, Lachnospira, Paludicola, Shuttleworthia, and Subdoligranulum. These differential abundant gut genera have been shown to harbor anti‐inflammatory properties. We did not find evidence of synergetic contributions of oral and gut genera to MCI. Conclusion Our results suggest that the saliva microbiome, like the gut microbiome, is disrupted as patients progress from NC to MCI. The pathogenic oral microbes we found were previously linked to periodontal and gingivitis pathogens. Further studies with larger sample sizes are needed to validate these findings.

INTRODUCTION We investigated the associations of leptin markers with cognitive function and magnetic resonance imaging (MRI) measures of brain atrophy and vascular injury in healthy middle‐aged adults. METHODS We included 2262 cognitively healthy participants from the Framingham Heart Study with neuropsychological evaluation; of these, 2028 also had available brain MRI. Concentrations of leptin, soluble leptin receptor (sOB‐R), and their ratio (free leptin index [FLI]), indicating leptin bioavailability, were measured using enzyme‐linked immunosorbent assays. Cognitive and MRI measures were derived using standardized protocols. RESULTS Higher sOB‐R was associated with lower fractional anisotropy (FA, β = −0.114 ± 0.02, p < 0.001), and higher free water (FW, β = 0.091 ± 0.022, p < 0.001) and peak‐width skeletonized mean diffusivity (PSMD, β = 0.078 ± 0.021, p < 0.001). Correspondingly, higher FLI was associated with higher FA (β = 0.115 ± 0.027, p < 0.001) and lower FW (β = ‐0.096 ± 0.029, p = 0.001) and PSMD (β = ‐0.085 ± 0.028, p = 0.002). DISCUSSION Higher leptin bioavailability was associated with better white matter (WM) integrity in healthy middle‐aged adults, supporting the putative neuroprotective role of leptin in late‐life dementia risk. Highlights Higher leptin bioavailability was related to better preservation of white matter microstructure. Higher leptin bioavailability during midlife might confer protection against dementia. Potential benefits might be even stronger for individuals with visceral obesity. DTI measures might be sensitive surrogate markers of subclinical neuropathology.

Alzheimer's disease and related dementias (ADRD) have been associated with alterations in both oral and gut microbiomes. While extensive research has focused on the role of gut dysbiosis in ADRD, the contribution of the oral microbiome remains relatively understudied. Furthermore, the potential synergistic interactions between oral and gut microbiomes in ADRD pathology are largely unexplored. This study aims to evaluate distinct patterns and potential synergistic effects of oral and gut microbiomes in a cohort of predominantly Hispanic individuals with cognitive impairment (CI) and without cognitive impairment (NC). We conducted 16S rRNA gene sequencing on stool and saliva samples from 32 participants (17 CI, 15 NC; 62.5% female, mean age = 70.4 ± 6.2 years) recruited in San Antonio, Texas, USA. Correlation analysis through MaAslin2 assessed the relationship between participants' clinical measurements (e.g., fasting glucose and blood cholesterol) and their gut and saliva microbial contents. Differential abundance analysis evaluated taxa with significant differences between CI and NC groups, and alpha and beta diversity metrics assessed within-sample and group compositional differences. Our analyses revealed no significant differences between NC and CI groups in fasting glucose or blood cholesterol levels. However, a clear association was observed between gut microbiome composition and levels of fasting glucose and blood cholesterol. While alpha and beta diversity metrics showed no significant differences between CI and NC groups, differential abundance analysis revealed an increased presence of oral genera such as , , and in CI participants. Conversely, CI individuals exhibited a decreased abundance of gut genera, including , , and , which are known for their anti-inflammatory properties. No evidence was found for synergistic contributions between oral and gut microbiomes in the context of ADRD. Our findings suggest that similar to the gut microbiome, the oral microbiome undergoes significant modifications as individuals transition from NC to CI. Notably, the identified oral microbes have been previously associated with periodontal diseases and gingivitis. These results underscore the necessity for further investigations with larger sample sizes to validate our findings and elucidate the complex interplay between oral and gut microbiomes in ADRD pathogenesis.

Background The Apolipoprotein E (APOE) ε4 variant is the strongest genetic risk factor for Alzheimer’s disease (AD) and has been thoroughly studied in non‐Hispanic whites (NHW). However, its association with AD among Hispanic individuals is unclear, with existing studies yielding mixed results. Genetics do not entirely explain the likelihood of developing AD. For example, several common vascular contributors are more common in Hispanic adults and have been associated with cognitive impairment and dementia. We sought to characterize the associations between Hispanic ethnicity with APOEε4, cognitive diagnosis, and vascular contributors using data from the South Texas AD Research Center (STAC, P30AG066546). Method Our study sample was derived from 215 STAC participants (N = 97 Hispanic, N = 118 NHW). Descriptive statistics of demographics and baseline characteristics were calculated for Hispanic and NHW participants (frequency and percentage for categorical variables, mean and standard deviation for continuous variables, Table 1). Table 2 shows APOE4 genotype distribution by ethnicity. Ethnicity‐specific associations between APOE4 and clinical diagnosis were assessed using multivariable logistic regression models, adjusting for covariates (age, sex, education). Multivariable regression models were used to assess the associations between APOE4 with clinical diagnosis adjusting for covariates (Table 3). Similar approaches were conducted for the combined sample with ethnicity by APOE4 interaction to test the ethnic differences. All analyses were conducted using SAS 9.4. Result We found APOEε4 was associated with AD‐dementia in all participants (OR = 2.81, 95% CI 1.29‐6.14, p = 0.0095). However, we did not find any interaction with ethnicity (in stratified analyses, NHW OR = 2.58, 95% CI 0.97‐6.86, p = 0.06; Hispanic OR = 3.12, 95% CI 0.84‐11.66, p = 0.09). APOEε4 was not significantly associated with MCI, hypertension, hypercholesterolemia, or type II diabetes mellitus, regardless of ethnicity. Conclusion Identifying and targeting population‐specific risk factors is crucial to developing effective prevention and treatment approaches for AD in the disproportionately burdened Hispanic population. Our findings support the established association between APOE ε4 and AD risk in both Hispanic and NHW adults. In our STAC cohort, we found no significant relationship between Hispanic ethnicity and APOE ε4. However, our study is limited by the small sample size, which we plan to expand in the future.

Background The MarkVCID consortium was established to address the paucity of biomarkers for vascular contributions to cognitive impairment and dementia (VCID), a leading cause of dementia. Plasma neurofilament light (NfL), a neuroaxonal injury marker elevated in several neurological and neurodegenerative diseases, was selected as one of the first biomarkers to be examined. We performed comprehensive instrumental and clinical validation of the Quanterix Simoa NfL assay using the first MarkVCID cohort. Method Plasma NfL was measured using HD‐X and HD‐1 Simoa instruments. Samples from the MarkVCID consortium were used to evaluate intra‐ and inter‐plate reliability, test‐retest repeatability, and inter‐site reproducibility. We used linear regression models to assess the association of NfL in MarkVCID with general cognitive function (GCF) as the primary outcome (n=331). In secondary analyses we assessed NfL associations with white matter hyperintensities (WMH). Models were adjusted for potential confounders, including eGFR as renal function influences NfL clearance. We replicated our findings using cohorts from the CHARGE consortium (CARDIA, ARIC, FHS, AGES; n=4,772), the UKY ADRC (n=350), and the UCD ADRC (n=196). Result We found the Quanterix Simoa platform to be reliable with low coefficients of variation (average CV<12%), high inter‐site reproducibility (overall ICC = 0.93) and high repeatability in test‐retest samples drawn within 30 days (ICC=0.968). There was strong consistency across Quanterix instruments (HD‐X and HD‐1; R2≥0.98) and kits (N4PA and single molecule NfL; ICC≥0.81). We observed consistent significant associations between higher NfL concentrations and worse GCF in MarkVCID (β=‐0.23; [95% CI ‐0.41; ‐0.01), CHARGE cohorts (meta‐analysis β=‐0.11; [95% CI ‐0.17; ‐0.06]), the UKY ADRC (β=‐0.16; [95% CI ‐0.27; ‐0.05]) and the UCD ADRC (UCD: β=‐0.28; [95% CI ‐0.48; ‐0.08). Secondary analyses revealed significant associations between elevated NfL concentrations and higher WMH burden in MarkVCID (when controlled for eGFR), CHARGE, and the UCD ADRC. Conclusion We have found that NfL can be reliably measured using the Quanterix platform, making this marker ideal for multi‐site clinical trials. We observed consistent associations for plasma NfL concentrations with cognition and WMH in MarkVCID and across independent samples, providing evidence that it can be a useful biomarker for stratification in VCID trials.