npj Aging

Drugs that slow the rate of organismal aging (geroprotectors) have the potential to improve human healthspan by preventing the development of multiple chronic diseases. The nematode C. elegans is a proven system for identifying anti-aging drugs, but methods for candidate nomination that scale to high throughput remain limited and have not been widely adopted. To accelerate the discovery process, we have developed an open-source AI-enabled screening platform that provides a rapid, automated, posture-based score of C. elegans survival. We used this workflow to screen a library of 2,782 FDA-approved drugs and identified 31 compounds that reproducibly increase heat stress resistance, a known predictor of longevity. Follow-up studies confirmed that many of these compounds confer lifespan extension in worms, and several compounds also have anti-senescent activity in human cells. This simplified and adaptable AI-enabled workflow therefore has the potential to accelerate the discovery of translatable drugs that slow aging.

Background: Cardiometabolic multimorbidity (CMM), which refers to having two or more cardiometabolic conditions like type 2 diabetes, stroke, and coronary heart disease, is becoming an increasing global health challenge. Although metabolic dysfunction and biological aging may jointly contribute to CMM development, most previous studies have examined these dimensions separately. Whether their combined assessment improves risk stratification and prediction across the cardiometabolic disease continuum remains unclear. Methods: This prospective cohort study involved 8,767 participants aged 45 and older who did not have CMM at the start, as part of the China Health and Retirement Longitudinal Study (CHARLS). Baseline evaluations included the triglyceride-glucose (TyG) index and two biological age algorithms, Light BA and KDM BA. The residual from regressing biological age on chronological age was used to derive BAA. Continuous TyG BA composite indices were constructed as the products of TyG and biological age. Cumulative exposure and two wave trajectory analyses used repeated measurements from 2011 and 2015. Multistate models examined associations across the cardiometabolic disease continuum. Cox proportional hazards models, along with restricted cubic splines and time dependent discrimination analyses, were utilized to examine associations, dose response relationships, and incremental predictive performance. Results: During a median follow-up span of 108 months, 873 participants were newly diagnosed with CMM. TyG and biological age were independently associated with CMM, with mutually adjusted hazard ratios of 1.23 to 1.27 and 1.39 to 1.44 per standard deviation increase, respectively. Individuals with elevated TyG and rapid biological aging faced the greatest CMM risk, showing hazard ratios of 2.37 for Light BA and 2.26 for KDM BA, despite the absence of a significant multiplicative interaction. Continuous TyG BA composites were associated with 49% to 62% higher CMM risk per standard-deviation increase, with more than threefold higher risk in the highest versus lowest quartile and nonlinear dose response relationships. Significantly increased CMM risk was linked to higher cumulative exposure and elevated two wave trajectory levels, with hazard ratios ranging from 3.93 to 5.17 when comparing the highest and lowest exposure groups. Multistate analyses demonstrated consistent associations of the composites with transitions across the cardiometabolic disease continuum and with mortality. Adding TyG BA composites to the prespecified clinical model increased the Cindex by 0.015 to 0.024 and improved net clinical benefit, but did not improve discrimination beyond models containing TyG and biological age as separate covariates. Associations were stronger in younger and non frail participants in exploratory subgroup analyses. Conclusions: Metabolic dysfunction and biological aging represent complementary dimensions of CMM susceptibility and progression. TyG BA composites provide a parsimonious summary of combined metabolic-aging burden and improve risk discrimination beyond conventional clinical factors, but should not be interpreted as superior to models retaining TyG and biological age separately. These findings support the potential utility of a metabolic aging framework for risk stratification and warrant external validation, particularly for its application in earlier stages of cardiometabolic disease development. Keywords: cardiometabolic multimorbidity; TyG index; biological age; metabolic aging composite; risk stratification; prospective cohort study

The term Precision Aging describes an approach that focuses on multi-domain profiles of risks impacting individual trajectories of age-related cognitive functioning. The goal of the present study was to identify profiles of risk within a sample of 555 adults, ages 50 to 79, without diagnosis of dementia. Using cluster analyses, we considered 38 risk factors associated with five categories of risk known to negatively impact cognitive aging - cardiovascular insufficiency, glucose dysregulation, inflammation, immune dysfunction, and neuropathology. Results yielded five profiles, including a group with low risk in all five risk categories, and four groups with prominent risks in specific domains. Importantly, all four high risk groups performed more poorly relative to the low risk group on multiple memory measures from a well-established neuropsychological test, the Auditory Verbal Learning Test. The results highlight the importance of considering multiple domains of risk within the same cohort to predict age-related cognitive functioning.

Background. Randomized controlled trials (RCTs) remain the reference standard for establishing clinical efficacy for candidate drugs, but their restrictive eligibility criteria limit generalizability, and for dietary supplements the body of well-powered RCTs is small relative to the number of proposed health claims. Self-reported real-world data (RWD) by patients in social media are increasingly recognized as a complementary evidence source, yet their value in the nutraceutical domain is largely uncharacterized. Objective. To test whether benefits that users positively report for natural ingredients on Reddit are statistically associated with benefits demonstrated for those ingredients in the clinical-trial literature, and to characterize what a community corpus can reveal about application areas and side effects. Methods. We assembled a cross-sectional corpus of 216,350 distinct comments from 86 supplement-related subreddits (January 2022 - April 2026), covering 329 canonical ingredients and a shared, MeSH/MedDRA-aligned vocabulary of 581 benefit terms. Comment-level directionality (benefit/no-effect/irrelevant) was assigned by a natural-language-inference model. The independence of clinical efficacy and Reddit endorsement was tested with 2x2 chi-squared and Fisher exact tests across a sweep of endorsement thresholds, plus per-ingredient tests with Bonferroni correction. Results. Of 31,359 unique (ingredient, benefit) pairs, 2,508 were efficacy-demonstrated under the primary definition. The two signals were statistically associated. The association strengthened monotonically with endorsement volume, reaching OR 3.06 at [≥]20 comments and 7.14 at [≥]100. Among heavily-endorsed benefits ([≥]100 comments) 38% were RCT-demonstrated, versus ~9% overall. Community attention concentrated on sleep, skin and anxiety, whereas the trial literature concentrated on cardiovascular, pain, metabolic and mood indications. The most discussed and clinically validated nutraceutical-health claim pairs include melatonin-sleep cycle and quality, ginger with gastrointestinal relief and zinc with skin conditions. The concordance analysis revealed that 81% (573/711) of clinically proved nutraceutical-health claim pairs were in agreement with the reported experience of the Reddit community. Conclusions. Community endorsement and clinical efficacy are independent at the single-comment noise floor but positively concordant once a benefit is endorsed by multiple users, with concordance rising with consensus. Reddit-derived RWD is a useful hypothesis-generating prior for nutraceutical efficacy and a complementary, though not confirmatory, signal for prioritizing ingredients and indications for formal clinical study taking into consideration personalized characteristics.

Aging is a multidimensional process, yet most aging models reduce it to a single score to estimate biological aging and predict health outcomes, disease risk, or mortality. Here, we introduce PUMA (Phenotypic Unsupervised Model of Aging), a framework that characterizes aging through multiple phenotypic dimensions. Applying PUMA to more than 1,000 traits spanning behavioral, psychological, social, physical, environmental, and biomedical domains in over 150,000 individuals from the Lifelines cohort, we identified seven distinct phenotypic aging dimensions. These dimensions were significantly associated with the future incidence of major age-related diseases--including cancer, diabetes, COPD, heart failure, stroke, and Parkinsons disease-- demonstrating the potential of PUMA to stratify individuals by disease risk and identify phenotypic domains for targeted intervention. Notably, dimensions reflecting psychosocial factors, particularly cumulative life stress, predicted disease risk as strongly as, or more strongly than, traditional biomedical risk factors, highlighting the importance of psychological and social influences in aging and disease risk. The observation that phenotypic aging dimensions are differentially associated with the future risk of age-related diseases supports a multidimensional model of aging, indicating that aging is not a single uniform process. Because PUMA relies on accessible phenotypic data, it provides an interpretable framework for disease risk stratification and targeted preventive strategies.

Background: India has a rising incidence of chronic non-communicable diseases, making it a major healthcare burden today. Growing evidence suggests that chronic low-grade inflammation links ageing with cardiometabolic disorders, captured by the emerging concept of inflammaging. However, most evidence on biological ageing comes from Western populations, with no similar models developed for the Indian population. Given the country's distinctive genetic makeup, unique exposome, and heterogeneous NCD presentation, Western models may not capture inflammaging and its effects in the Indian population. Methods: We analysed baseline data from 4,240 adults in the Phenome India CSIR Health Cohort Knowledgebase (PI CheCK), a nationwide multi-centre cohort. Participants were stratified into eight cardiometabolic phenotype groups by BMI (Asian cut off), blood pressure and HbA1c status. We trained a Super Learner ensemble to predict chronological age in the lean normotensive-normoglycaemic reference group (n=615) using 44 plasma cytokines, sex, haemoglobin, and bioimpedance-derived visceral fat area, per cent body fat, and total body water. Performance was assessed by repeated five-fold cross-validation and in a held-out healthy test set. Calibrated biological age acceleration was then estimated in the remaining 3,625 participants. Results: Median age was 51.0 years (IQR 41.0 to 62.0) and 49.4% were female. The Super Learner outperformed elastic net and XGBoost comparators. Permutation importance identified visceral fat area, per cent body fat, CTACK, SDF1a, haemoglobin and sex as leading contributors, with body composition measures accounting for the largest share, indicating an immune-metabolic rather than cytokine-only signal. Biological age acceleration was concentrated in overweight/obese phenotypes. Lean phenotypes showed acceleration close to the reference (0.32 0.50 years). Conclusions: Cytokine and body composition measures capture a quantifiable immunometabolic ageing signal in a South Asian cohort, with acceleration driven predominantly by adiposity. External validation and longitudinal follow up are required.

Hutchinson-Gilford progeria syndrome (HGPS) is an ultra-rare premature aging disorder caused by progerin, a truncated lamin A variant generated by a silent de novo mutation activating a cryptic splice site in LMNA. The resulting morphological, epigenetic, genomic, and proteostasic defects closely recapitulate some hallmarks of cellular aging. Here, we identify the Parkinsons disease-associated kinase LRRK2 as a critical regulator of HGPS pathology and physiological aging. Rab29-mediated LRRK2 hyperactivation exacerbates progerin-induced cellular aging, whereas LRRK2 knockdown or overexpression of its opposing phosphatase, PPM1H, ameliorates progerin-induced defects. Progerin-expressing cells exhibit altered intracellular trafficking, which is regulated by LRRK2 and links diverse aging hallmarks. Consistent with these findings, reducing LRRK2 levels mitigates cellular aging phenotypes in physiologically aged cells, and loss of the C. elegans ortholog lrk-1 preserves aging-associated loss of motility and extends organismal lifespan. Together, our findings establish LRRK2 as a central node in cellular aging and position it as a potential therapeutic target for aging-related defects in both HGPS and physiological aging.

Background: Polypharmacy is an escalating global health challenge, yet longitudinal evidence regarding its impact on mortality in Latin American aging populations remains limited. This study evaluated the association between medication burden and all cause mortality among community dwelling older adults in a rapidly aging region of Colombia. Methods: A longitudinal analysis was conducted using a sub-cohort of 4,110 participants (aged 60 years or more) from the SABE Colombia survey (Antioquia, Caldas, Risaralda, and Quindio). Vital status was adjudicated via the National Health System Resources Administrator (ADRES) database over a mean follow-up of 79 months. Polypharmacy was defined as the concurrent use of 5 9 medications and excessive polypharmacy as 10 or more. Extended Cox proportional hazards models were employed to estimate hazard ratios (HR), adjusting for sociodemographic factors, multimorbidity, and functional dependency. Results: At baseline, 20.2% of participants presented polypharmacy and 2.1% excessive polypharmacy. A total of 1,092 deaths (26.6%) were recorded during follow-up. After multivariable adjustment, both moderate polypharmacy (HR 1.17; 95% CI 1.02 - 1.31; p=0.029) and excessive polypharmacy (HR 1.82; 95% CI 1.34 - 2.47; p<0.001) were identified as independent predictors of mortality. Notably, the risk was markedly higher at the 10 or more medication threshold, suggesting a non-linear relationship between pharmacological burden and survival. Conclusions: Polypharmacy is a significant and independent predictor of mortality in Colombian older adults, with the risk nearly doubling in cases of excessive medication use. These findings underscore the urgent need for structured medication review and deprescribing interventions tailored to resource-constrained healthcare systems to mitigate the risks associated with high pharmacological accumulation. Keywords: Polypharmacy, Aged, Mortality, Longitudinal, Colombia.

Background: Accelerated biological aging can be assessed with DNA methylation (DNAm)- based epigenetic clocks. Research suggests that greater DNAm is associated with faster cognitive decline and risk of Alzheimer disease (AD) and other dementias. However, most studies have relied on single-time-point measurements of clocks, rather than evaluating dynamic changes over time. We examined the association between 15-year epigenetic aging trajectories and brain health outcomes in midlife. Methods: We analyzed 2,833 middle-aged adults (mean baseline age 40 years, 59% female and 44% Black) with [&ge;]3 DunedinPACE (a recently developed epigenetic clock) measurements, collected over 15 years. Using mixed-effects modeling, we derived individual-specific slopes of epigenetic aging trajectories and categorized participants as Fast Agers (slopes > 1 SD above the mean), Slow Agers (slopes < 1 SD below the mean), or Typical Agers (within &plusmn1 SD of the mean). We examined associations between trajectory group and cognition on five cognitive domains as well as on plasma AD biomarkers (NfL, p-tau217, A{beta}42/A{beta}40), all assessed 15-20 years post-baseline. Models were adjusted for demographics, education, physical activity and APOE*{varepsilon}4 carrier status (with additional adjustments for eGFRcr for biomarker outcomes). Results: Epigenetic aging trajectories were associated with multiple domains of cognition and AD biomarkers (Figure 1). Compared to Typical Agers, Fast Agers showed worse processing speed, memory, executive function, and global cognition (all p<0.05), with no difference in verbal fluency. Slow Agers had better performance on memory and global cognition (both p < 0.05). Fast Agers also exhibited significantly lower A{beta}42/A{beta}40 levels (p = 0.011) compared to Typical agers; no significant associations with p-tau217 or NfL were observed in either group. Conclusion: Middle-aged adults with faster 15-year epigenetic aging trajectories demonstrated worse cognitive performance, whereas those with slower biological aging trajectories exhibited cognitive resilience and more favorable AD biomarker profiles. By examining long-term trajectories rather than single timepoints, these findings identify individuals at differential risk for brain health outcomes.

MicroRNAs (miRNAs) are small non-coding RNAs that play critical roles in regulating cellular senescence and aging. Our recent studies identified a conserved C. elegans miRNA cluster (miR-229/64/65/66) that is required for normal adult lifespan, with overexpression significantly extending longevity. Notably, cel-miR-229 is evolutionarily conserved in humans, with hsa-miR-425 sharing an identical seed sequence. Here, we investigated the role of miR-425 in mammalian cellular senescence. We found that miR-425 expression is markedly reduced in pharmacologically induced senescence in human lung cancer cells. Restoration of miR-425 expression attenuates senescence and suppresses the expression of senescence-associated secretory phenotype (SASP) cytokines following senescence induction. We further observed that miR-425 levels decline during replicative senescence, whereas stable overexpression in WI-38 fibroblasts delays senescence accumulation and preserves proliferative capacity. Mechanistically, miR-425 suppresses TGF-{beta} signaling, leading to reduced expression of the cyclin-dependent kinase inhibitor p21/CDKN1A and increased phosphorylation of the retinoblastoma (RB) protein, thereby promoting cell-cycle progression. We further identify PPP2CB, the catalytic subunit of protein phosphatase 2A (PP2A), as a direct target of miR-425. PPP2CB expression is downregulated in miR-425-5p overexpressing cells, even under senescence induction. Knockdown of PPP2CB using siRNA phenocopies the effects of miR-425 overexpression, reducing senescence, enhancing proliferative potential, and increasing RB phosphorylation. Collectively, our findings identify miR-425 as a conserved regulator of cellular senescence that acts through upregulation of RB phosphorylation. These results establish a novel miR-425-PPP2CB-RB regulatory axis controlling proliferation and senescence and suggest miR-425 as a potential therapeutic target for mitigating senescence to promote extended health span.

Background Understanding the mechanisms underlying brain aging and age-related pathological changes is essential for advancing brain health research. Our group previously developed a mechanistic mathematical model of healthy brain, Chamberland et al. (2024) that integrates key biological processes involved in normal aging, from which Alzheimer's disease (AD) related changes may emerge naturally. Objectives To characterize and validate this brain model by evaluating its sensitivity, calibrating its parameters, and assessing generalizability in independent populations. Methods The model represents the evolution of key biological processes associated with brain aging, including amyloid beta (A{beta}), tau pathologies, neuroinflammation, and neuronal death. After identifying the 30 most influential parameters, we calibrated the model using cognitively normal (CN) participants from the AD Neuroimaging Initiative (ADNI) database (n = 211) by minimizing a loss function composed of three outcomes (AB) plaques, tau tangles, and neuronal density). The calibrated model was then applied to the UK Biobank cohort (n = 35,899) of normal controls (aged 44-82 years). The effects of sex and APOE were evaluated using stratified simulations. Results Parameter calibration significantly reduced the prediction errors for A{beta} and tau. Neuronal density predictions showed strong agreement in the UK Biobank cohort. The variance decomposition identified APOE status as a major contributor to variability in A{beta}. Conclusion Our validated brain health model links mechanistic pathways with population data and reproduces neuronal density patterns in an independent cohort. These findings support its use as a framework for studying brain aging and investigating how Alzheimer's disease related pathological changes may emerge with aging.

Cognitively normal older adults are often regarded as a homogeneous population in preventive and disease-modifying clinical trials for dementia. However, longer-term cognitive aging outcomes vary substantially in this population, and this variability remains poorly understood. Here, we leveraged rich multimodal, multi-domain biomarker profiles from a large prospective cohort (N=1,136), and Deep Embedded Clustering, to cluster cognitively normal older adults into biologically distinct subgroups. Input data included cortical thickness derived from MRI, plasma Alzheimer's disease (AD) biomarkers, plasma inflammatory biomarkers, and vascular measures. The deep clustering algorithm identified three biologically distinct subgroups within the sample, stratified along a gradient of neurobiological burden (low, intermediate, and high). Cortical thinning and inflammatory burden were the primary drivers of clustering assignments. The High-Burden subgroup showed significantly worse memory and executive function, elevated cardiometabolic comorbidity, and markedly higher rates of conversion to mild cognitive impairment or dementia within two years. The results were validated in an independent external sample. The study reveals marked variability among individuals who are otherwise all defined as cognitively normal, and provides a data-driven stratification framework for enriching disease-modifying and preventive trials by identifying cognitively normal individuals at high risk for future cognitive decline.

Importance Socioeconomic disadvantage is associated with accelerated brain aging. However, the modifiable factors accounting for this association, and whether they differ across socioeconomic indicators, remains unclear. Objective To determine whether modifiable risk factors account for socioeconomic differences in the brain age gap, and whether the contributions of these risk factors differ between individual-level and area-level socioeconomic indicators. Design, Setting, and Participants This cohort study used data from participants in the UK Biobank, a population-based cohort recruited at ages 40 to 70 years from 2006 to 2010. Participants with T1-weighted and T2-FLAIR brain magnetic resonance imaging at first imaging visit were eligible; 7700 participants used for model development in previous work were excluded, yielding 36 878. Data were analyzed from April to July 2026. Exposures Household income, highest educational attainment, and area-level deprivation (Townsend Deprivation Index). Main Outcomes and Measures Brain Age Gap (predicted minus chronological age, years) from T1-weighted (primary) and T2-FLAIR (secondary) magnetic resonance imaging, derived with a deep learning model. Eleven risk factors and the Life's Essential 8 composite cardiovascular health score were modeled as mediators; indirect effects were estimated in single-mediator and parallel mediation models with 95% confidence intervals from 5000 bootstrap resamples. Results Among 36 878 participants (mean [SD] age, 65.1 [7.7] years; 20 360 [55.2%] female), lower income and greater area deprivation were associated with a larger brain age gap: lowest vs highest income group, 0.35 years (95% CI, 0.22-0.47); most vs least deprived quartile, 0.33 years (95% CI, 0.23-0.43). Education showed weaker associations that differed in direction between imaging contrasts. Life's Essential 8 score mediated 36% of the income (indirect effect, 0.031 [95% CI, 0.025-0.036]) and 17.9% of the area-deprivation (0.024 [95% CI, 0.019-0.029]) associations. In parallel models, where all risk factors were entered simultaneously, smoking was the largest mediator for both income (0.022 [95% CI, 0.016-0.028]) and area-deprivation (0.030 [95% CI, 0.023-0.037]). Higher income was associated with higher alcohol intake, offsetting part of the income association. Conclusions and Relevance Socioeconomic differences in brain age gap were partly accounted for by modifiable cardiovascular and lifestyle risk factors, with smoking being the single largest contributor. These findings identify modifiable cardiovascular risk factors as a substantial component of socioeconomic inequalities in brain aging.

Reduced nicotinamide mononucleotide (NMNH) is a reduced NAD precursor with reported NAD- augmenting activity in preclinical models; however, controlled human data remain limited. This was a randomized, double-blind, placebo-controlled, parallel-group phase I trial evaluating oral NMNH-Ca in healthy adults aged 40-65 years. Eighty participants received placebo or NMNH-Ca 125, 250, or 500 mg once daily for 90 days. The primary objective was safety and tolerability. Whole-blood NAD was assessed as the key pharmacodynamic endpoint, including a 24-hour post-dose substudy, with biomarker-derived blood phenotypic age, treadmill-based six-minute walk distance, body mass index, and SF-36 domains analyzed as exploratory outcomes. NMNH-Ca was well tolerated at all doses, with no serious adverse events, treatment-related adverse events, or discontinuations. In the acute substudy, whole-blood NAD increased after single-dose NMNH-Ca, with peak mean concentrations at 12 hours. Over 90 days, NAD increased in a dose-related pattern; Day 90 mean changes from baseline were 2.33 {+/-} 18.53 M with placebo and 8.22 {+/-} 10.25, 15.85 {+/-} 11.16, and 39.90 {+/-} 14.11 M with NMNH-Ca 125, 250, and 500 mg, respectively. Exploratory analyses showed hypothesis-generating favorable signals in blood phenotypic age, treadmill-based six-minute walk distance, and health-related quality of life, most consistently at 500 mg. Oral NMNH-Ca was safe and pharmacodynamically active over 90 days, supporting larger and longer confirmatory trials with prespecified geroscience endpoints and tissue-relevant NAD metabolomics.

Neurodegenerative diseases, including Alzheimer's disease (AD), are strongly associated with aging. However, the molecular mechanisms underlying pathological brain aging remain incompletely understood. In this study, we used a mouse model of telomere attrition, a major driver of cellular senescence, to perform an unbiased analysis of how telomere-driven senescence affects cellular physiology and contributes to processes relevant to neurodegenerative conditions. After validating the presence of senescence hallmarks in telomerase-deficient brains, we characterized their transcriptomic and proteomic profiles. Mitochondrial function and associated energy metabolism emerged as the major dysregulated pathways, driven predominantly by proteomic rather than transcriptomic changes. Functional biochemical analyses on isolated brain mitochondria demonstrated impaired electron transport chain (ETC) complex activity and reduced energetic status, despite preserved ETC complex integrity and mitochondrial content. Further analyses in senescent primary neurons indicated an accumulation of dysfunctional mitochondria, characterized by increased reactive oxygen species (ROS) production and reduced ATP levels, although basal cellular respiration was maintained. At the tissue level, these alterations were associated with moderate reductions in neuronal density in the subiculum and cortical layer V, indicating region-specific vulnerability rather than widespread neurodegeneration. We propose that a major consequence of telomere dysfunction associated with pathological brain aging is the downregulation of mitochondrial activity, which contributes to the selective vulnerability of specific brain regions. These findings highlight mitochondrial pathways as attractive targets for interventions aimed at preserving brain health during aging.

Fasting-based dietary interventions are conserved regulators of aging that extend lifespan across species, including Caenorhabditis elegans. However, fasting studies in C. elegans are sensitive to experimental variables that can independently influence lifespan and health, including FUdR, antibiotic treatment, germline-less mutants, and the use of UV- or heat-killed bacteria. FUdR can alter lifespan, age-associated pathology, and stress responses, while antibiotics used to prevent bacterial growth during fasting may directly affect worm physiology. To minimize these confounding factors, we developed a simple adult-onset intermittent fasting paradigm that does not require FUdR, antibiotics, or bacterial killing. Wild-type worms were subjected to daily fasting periods of 5 h, 6 h, or 18 h until day 10 of adulthood and compared with continuously fed controls. Daily intermittent fasting robustly extended lifespan by 24-57%, demonstrating that repeated fasting windows during adulthood are sufficient to promote longevity under minimally confounded conditions. These findings establish a straightforward and experimentally tractable intermittent fasting paradigm for C. elegans and underscore the importance of limiting pharmacological and microbial conditions in dietary-intervention experiments.

A central challenge in computational geroscience is to distinguish molecular quantities that predict mortality from those that causally drive it. Epigenetic clocks and aging biomarkers are increasingly used as if they were that mechanism, yet this is rarely tested directly. This distinction also bears on competing theories of aging: damage/reliability (A), hyperfunction/mTOR-IIS (B-1), and information loss (B-2). Although individual aging proteins have been tested piecemeal, no study has asked, in one framework, what fraction of mortality is measurable, whether it is causal, and whether it is reversible. Using only public, de-identified data, we evaluate this three ways. First, a Markov generator-matrix model of hallmark-load dynamics with death as an absorbing state, fitted by Bayesian inference through a joint biomarker-and-mortality likelihood to NHANES with linked mortality (n=23,844) and replicated in the Health and Retirement Study (HRS), decomposes Gompertz acceleration into visible (measured-biomarker-driven) and latent components. Second, a positive-control-calibrated, two-platform cis-pQTL Mendelian-randomization and colocalization design (UKB-PPP, deCODE) against parental-lifespan GWAS tests whether the latent's measurable components are causal. Third, a clock battery (Horvath, chronological; DamAge, causality-enriched damage) tests reversibility in cellular reprogramming. Within the model, ~92% of Gompertz acceleration is assigned to a latent component not captured by measured blood-biomarker axes (NHANES 92.5%, HRS 91.6%); the latent is partly encoded in DNA-methylation signatures but not transcription. The known causal proteins are detected (LPA p=9x10-12; IL6R p=2.8x10-5), yet the latent's components, across inflammatory, renal and growth-signalling (IGFBP3, IGF-1) axes, are null and do not colocalize on either platform. Reprogramming reverses the chronological clock (-11 to -22 yr) but not the causality-enriched damage clock. The model-inferred mortality-driving component is largely latent to accessible biomarkers; its measurable molecular proxies show no supported causal effect where the design detects known causes; and the causality-enriched damage-clock signal is resistant to partial reprogramming.

BACKGROUND: Accumulations of AD and LATE-NC both contribute to changes in hippocampal volume, possibly via distinct and/or overlapping mechanisms. Microglia-driven inflammation is a shared pathway associated with both AD and LATE-NC. However, the extent to which microglia inflammation is associated with hippocampal volume is less understood. OBJECTIVE: Examine the relationship between AD and LATE-NC with hippocampal volume in persons with differing levels of microglia inflammation. METHODS: Cerebral hemispheres from 441 older adults who came to autopsy were studied. All hemispheres underwent ex-vivo MRI and detailed neuropathologic examination for neurodegenerative and cerebrovascular pathologies. Microglia were quantified in the hippocampal CA1/subiculum region using machine learning-based classifiers trained on digitized CR3-43-stained images via the HALO digital pathology platform. First, linear regression models examined the association of microglia with hippocampal volume, adjusting for demographics, postmortem interval (PMI), and common age-related pathologies. Second, linear regression models were employed to examine whether microglia density modified associations of {beta}-amyloid, tangle, or LATE-NC on hippocampal volume. RESULTS: Participants had a mean age of 90 years at death with 75% being women. Intermediate or high likelihood ADNC was present in 64% and LATE-NC (stage 2/3) was present in 52%. In linear regression models, adjusting for demographics and PMI, higher microglia density was associated with a lower hippocampal volume to hemisphere ratio (estimate = -0.021 SE=0.01, p=0.002); however, after adjusting for common age-related pathologies the association was attenuated (p=0.70). {beta}-amyloid, tangles, and LATE-NC remained independently associated with a lower hippocampal volume. The association of LATE-NC with hippocampal volume was stronger in brains with greater microglia burden (estimate for the interaction term = -0.016; SE=0.01, p=0.002). No interactions were seen between {beta}-amyloid or tangles with microglia on hippocampal volume. In stratified analyses, microglial density modified the association between LATE-NC and hippocampal volume, independent of AD neuropathologic status. CONCLUSION: Microglia-driven inflammation strengthens the association of LATE-NC, but not AD pathology, on hippocampal volume loss. These findings emphasize the importance of inflammatory pathways [when interpreting MRI-based neurodegeneration markers] in aging and mixed pathology.

Sleep disturbances are common among older adults and are often closely associated with anxiety symptoms, which together can substantially compromise physical and mental health.A cross-sectional analysis was conducted using data from the 2017/2018 wave of the Chinese Longitudinal Healthy Longevity Survey (CLHLS). The study included 6,106 Chinese older adults (aged [&ge;]65 years) living in empty-nest households. Physical exercise was measured based on self-reported regular engagement in exercise, and social participation was defined as involvement in organized social activities (e.g., community or group-based events). Associations between sleep quality and duration and anxiety were estimated using multivariable logistic regression, and mediation effects of physical exercise and social participation were tested using bootstrap resampling.Among the 6,106 participants, 593 (9.7%) reported anxiety symptoms. Multivariable logistic regression analysis indicated that poor sleep quality was significantly associated with a higher risk of anxiety (OR = 3.23, 95% CI: 2.62-4.01, P < 0.001). Short sleep duration was also an independent risk factor for anxiety (OR = 1.34, 95% CI: 1.04-1.74, P = 0.025), whereas long sleep duration showed no significant association. Subgroup analyses stratified by sex, marital status, and economic status consistently revealed significant associations between sleep (both quality and duration) and anxiety, with no statistically significant interactions observed. Mediation analyses demonstrated that physical exercise significantly mediated the relationships of both sleep quality and long sleep duration with anxiety (all P < 0.01, with bootstrap confidence intervals excluding zero). Similarly, social participation significantly mediated the relationships of both short and long sleep duration with anxiety (all P < 0.01, with bootstrap confidence intervals excluding zero).In Chinese empty-nest older adults, both poor sleep quality and short sleep duration are independent risk factors for anxiety symptoms, with sleep quality exerting a stronger influence. Physical exercise partially mediated the associations between sleep quality and anxiety and between long sleep duration and anxiety, whereas social participation mediated the association between sleep duration (short and long) and anxiety. Improving sleep quality and ensuring adequate sleep duration may help reduce anxiety risk, and interventions promoting physical exercise and social participation could enhance these protective effects.

The female reproductive system is one of the first major organ systems to show signs of age-related decline, and menopause is associated with increased risk of several diseases, including osteoporosis and cardiovascular disease. Menstrual fluid contains a mixture of blood and endometrial tissue and is a noninvasive biological sample type that has immense potential for diagnostics related to female reproductive aging. However, existing epigenetic aging clocks show limited performance in hormone-dependent tissues such as the endometrium. At Xella Health, we collected menstrual fluid (MF) samples, from a diverse patient cohort (n=66) and quantified genome-wide 5mC methylation levels. We then developed a novel, deep learning-based epigenetic aging clock that is optimized for performance in menstrual fluid and endometrial tissue. Our model, the Xella Clock, outperforms other widely used epigenetic aging clocks at predicting chronological age from MF data and on endometrial tissue. The model is a useful tool for advancing the study of female reproductive aging and can be used to examine associations between endometrial age acceleration and clinical factors.