GeroScience

Antagonistic pleiotropy of the IGF-1 signaling cascade is well recognized, as it promotes growth and development at younger ages and delays aging later in life. The goal of this study is to test in a mouse longevity experiment whether orally delivered small-molecule IGF1R inhibitors have promise as an anti-aging therapy. C57BL/6 mice (25 male and 25 female mice per treatment) were treated with selective IGF1R inhibitors, picropodophyllin (PPP) or 5-[3-(phenylmethoxy)phenyl]-7-[trans-3-(1-pyrrolidinylmethyl)cyclobutyl]-7H-pyrrolo[3-d]pyrimidin-4-amine (NVP-ADW742), via powdered diets starting at 13 months of age, and physiological and behavioral parameters, as well as survival, were assessed. Both compounds protected both sexes from short-term memory decline; reduced systolic blood pressure in males and pulse rate in both sexes; rescued declining glucose tolerance in males; and abolished grey hair development, reduced frailty, and protected against decline in grip strength in female mice. There were no sex differences in survival curves within groups. No significant differences between groups were observed in the Kaplan-Meier analysis. However, the survival curve in the NVP-ADW742 group was "squarer" than in controls, indicating a 93-day longer healthspan (p = 0.02). PPP treatment was associated with toxicity (GI bleeding). Additional analysis of the drug likeness of NVP-ADW742 demonstrated potential cardiotoxicity and brain bioaccumulation. To conclude, small-molecule IGF1R inhibitors hold promise as a therapy that may improve human health span and lifespan; however, both molecules tested in this study have side effects that may outweigh their anti-aging effects. Statements and DeclarationsYB is an employee of ReGENE LLC. GB received compensation from ReGENE LLC as a consultant. CJE received compensation from and is a member of ReGENE LLC. AS received compensation from and is a member of ReGENE LLC. TS declares no conflict of interest.

Quantifying biological aging is crucial for understanding functional decline before the onset of morbidity. While many accelerated aging and frailty measures based on clinical data exist for humans and several for rodent models of aging, there are few options for non-human primates (NHPs). NHP clinical data has several unique features including a lack of clinically delineated normative values for features and variability in data collection over long lifespans. There are also wide discrepancies in the number of available clinical measures and number of animals across data sets. To address these challenges, we developed and validated "Aging Resilience" (AR) metrics using longitudinal, routine clinical data from two distinct non-human primate cohorts: 4,328 baboons and 281 rhesus macaques. We trained five computational models--including Linear Mixed-Effects Models, Random Forest, and Recurrent Neural Networks (RNN)--to predict chronological age, subsequently deriving AR metrics that represent the velocity (Rate of Aging) and cumulative burden (Normalized Cumulative Aging) of physiological deviation. While linear models achieved high precision in predicting chronological age (test R2 up to 0.99), they correlated poorly with actual lifespan. In contrast, AR metrics derived from non-linear models (RNN and Random Forest) displayed strong predictive validity for mortality (Pearsons r > 0.8). These findings highlight a critical paradox: models that best predict chronological age do not necessarily capture the biological resilience determining healthspan. This study establishes a scalable framework for monitoring biological aging in translational models using standard veterinary records.

Biological-age models quantify the physiological aging process by relating biomarker profiles (e.g., blood biochemistry, DNA methylation) to all-cause mortality risk. These models outperform chronological age in predicting disease and mortality, making them useful metrics for preventative health. However, in existing biological-age models, biomarker contributions do not align with the non-linear associations biomarkers exhibit with long-term mortality risk, nor do they account for normative trajectories that occur in healthy aging, limiting their utility in a clinical setting. To address these limitations, we developed a biological-age framework (NiaAge) where biomarker contributions are derived directly from non-linear associations with long-term mortality risk and aligned with normative trajectories observed in healthy aging. As a result, biomarker contributions to NiaAge are consistent with known biomarker risk profiles and normative reference ranges. We trained NiaAge in the 1999-2000 cohort of the US National Health and Nutrition Examination Survey (NHANES; N=2028) on 59 biomarkers spanning multiple physiological domains (e.g., hematology, metabolism, inflammation), then evaluated it in the 2001-2002 cohort (N=2346). NiaAge predicted long-term mortality, physical-health, and cognitive-health significantly better than chronological age. It also outperformed several DNA-methylation age clocks on mortality and physical/cognitive health-span metrics, while performing comparably to leading physiological age clocks. These results position NiaAge as a valuable tool for preventative health.

CD31+ T-cells reportedly possess angiogenic properties. These cells have recently been termed angiogenic T-cells (TANG). Advancing age is associated with altered circulating T-cell phenotypes, including TANG, and reduced angiogenesis. We examined various TANG subsets (CD3+, CD4+, CD8+), and their VEGF-A intracellular content in young (n=16, 18-30 years) and older (n=16, 50-65 years) male adults using flow cytometry. Cardiorespiratory fitness ([V]O2max) was quantified in all participants using a graded cycling ergometry test to volitional exhaustion. Resting blood samples were collected to measure circulating IL-6 and cytomegalovirus serostatus. CD31+ T-cells (TANG) contained more VEGF-A than CD31- T-cells (CD31+: 9374 {+/-} 8587 AU vs CD31-: 8722 {+/-} 8149 AU, p = 0.021) which was also exhibited in CD4+ and CD8+ subsets. Older adults possessed fewer CD4+ TANG cells as a proportion of total CD4+ T-cells than younger adults (young: 35 {+/-} 11%; older: 24 {+/-} 9%, p = 0.004), and CD3+ and CD4+ TANG subsets from older adults exhibited higher VEGF-A levels than younger adults (CD3+CD31+: young: 6081 {+/-} 4001 AU; older: 13426 {+/-} 10945 AU, p = 0.019; CD4+CD31+: young: 6373 {+/-} 3972 AU; older: 15660 {+/-} 12829 AU, p = 0.011). TANG cells were not associated with circulating IL-6, and TANG VEGF-A content was not associated with[V] O2max. Advancing age is associated with a pathological TANG phenotype, which may contribute to age-related inflammation and warrants further investigation as a potential therapeutic target.

Heart rate variability (HRV) is widely used to assess autonomic regulation, but its interpretation in older adults is influenced by age, sex, body composition, and hemodynamic status, particularly in underrepresented populations living in geographically extreme environments. We analyzed 530 community-dwelling older adults from the Magallanes region in southern Chile using an integrated framework that combined HRV indices with demographic, anthropometric, and cardiovascular descriptors. After quality-controlled preprocessing, we characterized the distribution and association structure of autonomic and physiological variables and then performed a large-scale unsupervised clustering benchmark across multiple feature spaces, dimensionality-reduction strategies, and clustering algorithms. Conventional descriptors explained only a limited proportion of HRV variability, whereas integrated multivariate analysis revealed a structured continuum of autonomic heterogeneity. A six-cluster solution provided the best compromise between separation, balance, and physiological interpretability, identifying profiles that differed in HRV magnitude, blood pressure burden, body composition, sex distribution, and age structure. These findings indicate that autonomic regulation in older adults cannot be adequately summarized by isolated descriptors such as age, body mass index, or blood pressure alone. Instead, it is better represented as a multidimensional physiological organization that supports future hypothesis generation for risk stratification and longitudinal monitoring in aging populations.

BackgroundThe risk of chronic diseases and multimorbidity increases with age, yet, individuals of the same age can strongly differ in healthspan, ranging from early manifestation of age-related disease to robust health into very old age. Plasma biomarkers, including metabolites and proteins, can capture intrinsic health status, thereby providing insights into the nature of this variation. These biomarkers have been widely explored to understand chronic and early disease risk but less so for disease resilience in mid- and late-life survival (i.e. after 90 years), or for multigenerational longevity. MethodsWe quantified 326 plasma proteins using data-independent mass spectrometry in two generations of the Leiden Longevity Study cohort: F1 nonagenarian siblings (late-life; age [≥]89; N=852) and F2 offspring and their partners (mid-life; age 30-80; N=2,282). Baseline plasma protein levels were tested for association with mid- and late-life survival, with up to 22 years of follow-up, and cardiometabolic healthspan, with up to 16 years of follow-up. By comparing F2 offspring and partners, we tested for plasma proteins associating with familial longevity. FindingsFour proteins: GSN, F2, CRTAC1, and HP, consistently associated with increased mid- and late-life survival, prolonged cardiometabolic healthspan, and familial longevity; representing overall resilience. Moreover, six proteins: APCS, C7, FCN2, HPR, GSN, and PIGR, associated with mortality independent of MetaboHealth, a well-established metabolomics-based mortality score. InterpretationWe identified GSN, F2, CRTAC1, and HP as promising candidate indicators of healthy aging and resilience, meriting further study. FundingZonMw, LUF, BBMRI-NL, VOILA, Jorg Bernards-Stiftung, Koln Fortune, and CECAD Research in contextO_ST_ABSEvidence before this studyC_ST_ABSAs the population ages, implementing biomarkers that are able to distinguish vulnerable individuals from highly resilient ones may help to alleviate the burden on our healthcare system. Several studies have shown that plasma-derived proteins change with chronological age and can be used to discern those at risk of disease or early mortality. However, most plasma proteome studies to date have focused either on cross-sectional analyses, short follow-up periods, and/or cohorts with a narrow age range, often centered around mid-life. These studies therefore do not capture the biological factors that contribute to survival up to high ages (longevity), disease resilience and sustained health. In addition, it remains unclear whether the proteins and underlying mechanisms associated with increased survival are consistent across mid and late-life. Added value of this studyThis study set out to investigate the potential of plasma proteins as markers for healthy aging and resilience, and examines the extent to which these associations are consistent across generations. Using the family-based Leiden Longevity Study cohort, including long-lived nonagenarian siblings, their middle-aged offspring, and their partners, we leveraged a unique design to study survival, mid-life health, and multigenerational longevity. We show that prospective (longevity) survival is associated with both age-dependent and age-independent protein effects. Most age-independent proteins displaying consistent associations across life stages. In addition, relative protein level differences were detectable on average ten years before the onset of cardiometabolic disease in mid-life, indicating signatures of future resilience or vulnerability. Four proteins (GSN, CRTAC1, F2, and HP) show consistent association with survival-related outcomes and are proposed as candidate markers of healthy aging. We further observe favorable differences in these proteins in families enriched for longevity, which is indicative of lower disease risk. These identified proteins implicate inflammatory and osteoarthritis related processes. Furthermore, we demonstrate that proteins capture survival domains distinct from those reflected by metabolomic measures, demonstrating the complementary value of plasma proteomics. Implications of all the available evidenceThese findings highlight candidate protein biomarkers of healthy aging and resilience, which may provide improved insight into the mechanisms underlying healthy aging. They also facilitate the development of more sensitive indicators of health, whose implementation may enable earlier and more effective interventions in both population health and clinical care.

Aging leads to cognitive decline due to reduced neuronal plasticity and increased brain inflammation. Disruption of perineuronal nets (PNNs) is a recognized strategy to enhance neuroplasticity. Hyaluronan forms the backbone of PNNs, and 4-methylumbelliferone (4-MU), an inhibitor of hyaluronan synthesis, has been proposed to disrupt PNNs and enhance neuroplasticity in young rodents. In addition, 4-MU is also known as an immune response regulator, although its effects within the central nervous system (CNS) have been less characterized. In this study, we investigated the impact of long-term oral 4-MU administration in aged mice (20-22 months old), focusing on PNNs intensity, memory, and neuroinflammation. PNN intensity increased with age, and 4-MU treatment reduced it in 22-month-old mice to levels observed in 10-month-old animals; in the novel object recognition test, treated 22-month-old mice performed comparably to or better than 10-month-old controls. Moreover, markers of aging-associated neuroinflammation--including astrocytic and microglial activation as well as peripheral immune cell infiltration--were normalized to 10-month-old levels or further diminished following 4-MU treatment. Importantly, chronic 4-MU administration was well tolerated in aged mice, with no serious adverse effects observed. Together, these results suggest that 4-MU mitigates PNNs accumulation and neuroinflammaging while enhancing recognition memory, supporting its potential as a safe therapeutic approach for age-related cognitive decline.

Cellular senescence increases in frequency with age and is implicated in age-related pathologies, and identifying circulating biomarkers of senescence holds great diagnostic potential. Circulating senescence signatures are predictive of many age-related traits and diseases, though cell type-specific senescence signatures have not been comprehensively explored. In this study, senescence signatures from the Senescence Catalog (SenCat), including 14 human cell types such as peripheral blood mononuclear cells, renal epithelial cells, vascular smooth muscle cells, among others, are examined for their clinical relevance in circulation in two longitudinal studies: 1,275 participants of the Baltimore Longitudinal Study of Aging (BLSA) and 997 participants of the Invecchiare in Chianti (InCHIANTI) study. Notably, pooled senescence proteins outperformed non-senescence proteins in predicting many clinical parameters such as age and hypertension, and in many instances cell type senescence signatures mapped most strongly to their corresponding health domain. Importantly, the immune cell senescence signature is associated with future onset of several diseases such as diabetes. This study demonstrates that circulating cell type-specific biomarkers of senescence can reveal higher resolution health status than previously attained. HIGHLIGHTSO_LICirculating senescence associated proteins tend to outperform non-senescence proteins as biomarkers of clinical phenotypes in two independent longitudinal studies. C_LIO_LIA core senescence signature developed from 14 human cell types predicted a range of clinical phenotypes during aging. C_LIO_LICell type senescence signatures more strongly associated with their corresponding health domains. C_LIO_LIThe immune cell senescence signature and others were associated with mortality and diabetes onset, highlighting relevance for assessing health trajectories. C_LI

Background: Epigenetic clocks based on DNA methylation (DNAm) have emerged as promising biomarkers of biological aging, yet their associations with cognitive performance remain inconsistent. This study investigates the relationship between epigenetic age acceleration and cognitive performance in older adults using 14 DNAm clocks from five generations of development. Methods: We analyzed data from the Berlin Aging Study II (BASE-II) using genome-wide DNAm profiles and cognitive assessments ascertained at baseline (T0) and two follow-up time points (T1, T2) in up to 1,014 individuals. DNAm-based age and age acceleration estimates were calculated using Biolearn and MethylCIPHER. Analyses focused on cross-sectional and longitudinal associations between DNAm clock estimates and cognitive performance, including sex-specific effects and comparisons with frailty as non-cognitive positive control. Results: Among all tested DNAm clocks, DunedinPACE (a third-generation clock) showed the strongest and most consistent associations with cognitive performance. In addition, the fifth-generation SystemsAge framework also demonstrated robust associations with cross-sectional and longitudinal cognitive outcomes. In contrast, second-generation clocks (GrimAge [v2], PhenoAge) showed occasional nominal associations, while first-generation clocks (Horvath [v1], Hannum) and the causally-informed, fourth-generation clocks (e.g. YingCausAge, YingDamAge) showed no noteworthy signals. Likewise, telomere length estimated from DNAm was not strongly associated with cognitive performance in this dataset. Conclusions: Our findings highlight DunedinPACE as a particularly informative biomarker for various aspects of cognitive aging, while other DNAm aging measures showed no consistent associations. Future work should further refine domain-specific epigenetic biomarkers to improve biological aging assessments and achieve a more reliable early detection of cognitive decline.

The knock-out mutation of the unique M13 family member, the Drosophila melanogaster (fruit fly) Neprilysin-like 15 (Nepl15), resulted in marked reductions of glycogen and glycerolipid storage in adult male flies, but a significant increase of glycogen storage in adult female flies, although the mutant flies consumed the same amount of food as the isogenic w1118 controls. The findings prompted us to characterize sex and age-specific effects of Nepl15 knock-out (Nepl15KO) mutation on lifespan, fertility and fecundity, physiology, cytophysiology, and overall health. The current study shows Nepl15 transcripts are expressed in all embryonic stages of the control flies. The mutant embryos show more glycogen storage, likely due to more maternal glycogen deposition in the eggs. Moreover, there are slight increases in the number of eggs laid, the percentage of pupariation, and the percentage of adult fly eclosion from pupae in the Nepl15KO mutant flies. Interestingly, Nepl15KO female, but not male flies, outlive the respective control flies when cultured on a standard diet. The mutant adult females show significantly less Target of Rapamycin (TOR) and more Sirtuin 6 (Sirt6) expression, changes that may synergistically contribute to their lifespan extension. In contrast, mutant males exhibit significant reductions in both TOR and Sirt6 expression, potentially offsetting their effects on longevity. Cellular health is further improved in mutant females, as evidenced by a marked reduction in reactive oxygen species (ROS), associated with a 1.5-fold increase in the Superoxide dismutase 2 (Sod2) expression at 7 days of age. Both sexes demonstrate improved gut barrier integrity at 40 days, with reduced "Smurf" leakage compared to age-matched controls. Optical cardiography reveals that heart rate in 40-day-old mutants is better preserved, resembling that of 7-day-old flies, whereas control flies show a pronounced age-associated decline. Functionally, Nepl15KO males and females outperform controls in a 6-cm climbing assay at 10, 20, 30, and 40 days of age, with the greatest difference observed at day 40. Following a 45-minute exercise bout at 10 rpm, mutant females continue to outperform controls at both 7 and 40 days, indicating preserved neuromuscular performance. Consistently, ATP levels are significantly elevated in 7- and 40-day-old mutant females, but not in mutant males. Interestingly, only 7-day-old mutant males exhibit increased mitochondrial inner membrane potential, which may enable more rapid ATP turnover when energy demand arises. No detectable differences are observed in thoracic muscle or mitochondrial ultrastructure, nor in overall mitochondrial number. However, no observable changes are noticed in the ultrastructure of the thoracic muscle and mitochondria, and the overall number of mitochondria in the mutant flies. Collectively, our findings demonstrate that Nepl15 loss-of-function confers health benefits at cellular, organ, and organismal levels, with pronounced sex-specific differences. However, the mechanisms by which aging mutant males sustain enhanced functional performance remain elusive.

Frailty is a multi-system syndrome causing increased susceptibility to health insults in older adults. Immune system dysregulation and inflammaging have emerged as mechanisms that may affect multiple organ systems in the frailty syndrome. This present study seeks to define the immune state in community-dwelling adults suffering from frailty. We evaluated a subgroup of 169 individuals enrolled in the Gut-brain Alzheimers disease Inflammation and Neurocognitive Study (GAINS). Participants in the GAINS study were scored for frailty using the Clinical Frail Scale. A panel of 27 inflammatory cytokines was analyzed from the serum of each participant. Frailty was present in 33 (19.5%) of the cohort, and was correlated with age, malnutrition, and cognitive assessments. Statistical analysis adjusting for clinical covariates revealed higher serum levels of IL-2, IL-10, and IL-17 in frail patients. Using machine learning classification, we developed a predictive model of frailty with strong discriminative performance (AUC 0.78). Individual element analysis via Shapley Additive Explanations (SHAP) revealed that inflammatory markers had the greatest influence on the model, and IL-7 was the single most important element in the prediction of frailty. Together, our data demonstrate a novel pattern in which T-cell regulatory inflammatory molecules as mediators of frailty, implicating cellular immunity as a potential mechanism of dysfunctional aging.

BackgroundVitamins are important modulators of intestinal health and may affect the gut-brain axis through microbial metabolites such as short-chain fatty acids (SCFAs). However, the neurocognitive effects of colon-delivered vitamins in older adults remain unexplored - a critical gap given the gut-brain axiss emerging role in cognitive aging. ObjectiveWe investigated the effect of a colon-delivered multivitamin (CDMV) supplement on intestinal health and neurocognitive outcomes in older adults at risk of cognitive decline. MethodsWithin the double-blind randomized placebo-controlled trial COMBI (ClinicalTrials.govID: NCT05675007), we included 75 older adults (60-75 years) at risk of cognitive decline based on lifestyle-related factors. Participants consumed a colon-delivered capsule with vitamins B2, B3, B6, B9, C and D3, or a placebo, daily for six weeks. Pre- and post-intervention, we employed neuroimaging, feces- and blood collection. Primary outcomes were fecal SCFA concentrations, working memory (WM)-related fMRI responses, and WM performance measured with the n-back task. ResultsAfter adjusting for baseline values, we found no significant between-group differences in total fecal SCFA levels (p=0.30) and WM performance (p=0.50). Post-intervention WM-related fMRI responses in the hippocampus (p=0.01; p{superscript 2}=0.09) and dorsolateral prefrontal cortex (dlPFC) (p=0.06; p{superscript 2}=0.04), driven by the right dlPFC (p=0.02), were higher in the CDMV group compared to placebo. Independent of intervention group, post-pre increases in fecal SCFA levels were significantly correlated to increases in dlPFC fMRI responses ({rho}=0.31; p=0.02) and WM performance ({rho}=0.43; p=0.001). ConclusionsOur findings suggest that CDMV supplementation increases WM-related responses of the dlPFC and hippocampus in older adults, but this effect was not accompanied by changes in fecal SCFA levels or WM performance. The positive correlation of within-subject changes in fecal SCFAs with changes in WM dlPFC responses and performance across intervention groups provides human evidence for gut-brain communication in cognitive aging beyond cross-sectional associations.

BackgroundOlder adulthood is often accompanied by declines in auditory processing and cognitive functioning, increasing the risk of reduced autonomy and quality of life. Multidomain lifestyle interventions have shown potential to counteract these changes, and choir-based activities represent a promising approach by simultaneously engaging auditory, cognitive, physical, and social domains. However, evidence regarding their feasibility and neurophysiological impact in community-dwelling older adults, particularly those without formal musical training, remains scarce. MethodsThis 9-month quasi-experimental feasibility study involved 54 community-dwelling older adults (mean age = 72.9 years) with no formal musical background. Participants self-selected into a choir-based intervention group, an active control group engaging in non-musical leisure activities, or a passive control group; however, some participants in the control groups were selected from the waiting list for the choir. Assessments were conducted at baseline and follow-up and included measures of global cognition, cognitive reserve, psychological well-being (Flourishing Scale), multidimensional frailty (Selfy-MPI), music perception, pure-tone audiometry, and auditory evoked potentials recorded using a standardized clinical oddball paradigm. ResultsThe choir-based intervention was feasible in a community setting. At the neurophysiological level, choir participation was associated with a bilateral, significant shortening of the N2-P3 inter-peak latency, indicating faster auditory-cortical processing. Additionally, through explorative analyses multidimensional frailty, as assessed by the Selfy-MPI, showed a significant reduction in individuals engaging in a higher number of activities, irrespective of group allocation. Similarly, psychological well-being revealed a decrease in flourishing scores in the passive control group relative to the choir group. No changes were observed in audiometric thresholds or music perception measures. ConclusionChoir-based multidomain participation is a feasible intervention for community-dwelling older adults without formal musical training and is associated with selective benefits in cognitive reserve, psychological well-being, auditory-cortical processing speed, and multidimensional frailty. These findings provide a foundation for a larger randomized controlled trial aimed at clarifying the cognitive, psychosocial, and neural mechanisms underlying choir-based interventions in ageing. Trial RegistrationThe upcoming trial has been prospectively registered on ClinicalTrials.gov (ID: NCT06767410; registration date: January 9, 2025).

Cellular senescence plays a pivotal role in aging and cancer, two major biomedical and socioeconomic challenges of our time. Therefore, its study has become crucial for the design of interventions based on its manipulation. In this sense, researchers have developed a wide variety of highly sensitive and accurate techniques to detect and quantify cellular senescence. Among them, the most popular is the original Senescence-Associated {beta}-galactosidase (SA-{beta}-gal) colorimetric assay, based on the use of the chromogenic substrate X-gal. This compound is cleaved by {beta}-galactosidase, producing an insoluble, blue precipitate of 5,5-dibromo-4,4-dichloro-indigo (commonly referred to as indigo). While this method remains the gold standard senescence assay, its quantification remains challenging due to the color-based readout. In this work, we describe a method, which we have named FA{beta}-gal (Fluorescence Analysis of {beta}-galactosidase), that exploits the far-red fluorescence of the {beta}-gal product indigo and allows the quantification of SA-{beta}-gal activity under any conventional wide-field fluorescence microscopy using the original X-gal assay. In addition, we developed workflows and software applications that standardize SA-{beta}-gal quantification in a semiautomatic and unbiased manner. We demonstrate that FA{beta}-gal measurements present a strong linear correlation with the percentage of senescent cells and show high sensitivity. Moreover, we show that this method is also applicable to tissue sections, underscoring the versatility of our approach. Therefore, FA{beta}-gal could be easily introduced into the routine of laboratories already using the original colorimetric assay, enhancing the accuracy, sensitivity and reproducibility of senescence detection.

Thermal perception is determined not only by sensitivity but also by precision, yet the latter is often overlooked in thermosensation and pain research. This study examined how ageing and diabetic polyneuropathy (DPN) affect the sensitivity and precision of thermal perception at the volar forearm and whether combining these parameters can aid in distinguishing patients from healthy controls. Using a Bayesian hierarchical modelling approach, we estimated psychometric function thresholds (sensitivity) and slopes (precision) for cold detection, warm detection, cold pain, and heat pain in 86 healthy adults (aged 21-80) and 34 patients with DPN. We assessed age- and neuropathy-related effects on these parameters. We also estimated these parameters separately for each participant and used the resulting estimates in classification analyses, to determine their utility in discriminating patients from controls. Ageing was associated with elevated detection and cold pain thresholds and reduced precision of cold detection. Patients with DPN showed similar patterns: higher detection thresholds and lower cold detection slopes while pain-related parameters were largely unaffected. These findings indicate that ageing and neuropathy produce qualitatively similar changes in thermosensory function, particularly affecting cold detection sensitivity and precision. Classification based on various combinations of thresholds and slopes successfully discriminated patients from controls, with cold detection slopes offering the best performance amongst classification analysis focusing on a single parameter. Combining threshold and slope parameters for a given modality did not significantly improve classification accuracy but combining thresholds and slopes of all modalities led to the best performance, with near perfect classification accuracy (AUROCC: .92, 95% CI [.86.97]). Modelling both thresholds and slopes provides a more comprehensive view of sensory decline and may enhance the detection of early or subtle sensory dysfunction.

BackgroundWhen creating risk prediction models for time-to-event data, methods that incorporate time are typically used. Random survival forests (RSF), an extension of random forests (RF), are one such class of models. We compared RSF to RF in the context of time-to-event outcomes in the ASPirin in Reducing Events in the Elderly (ASPREE) randomized controlled trial. We hypothesize that RSF will have superior discrimination and calibration versus RF. MethodsParticipants from ASPREE residing outside the US or with missing data were excluded. A total of 2,291 participants were assigned 1:1 into training and test sets. RF and RSF models were trained using a total of 115 measures as candidate predictors. The outcome of interest was the earliest of incident dementia, physical disability, or death. ResultsThe primary endpoint occurred in 10.5% of participants. Discrimination was similar between the models: sensitivity ([~]0.75), specificity ([~]0.57), positive predictive value ([~]0.17), time dependent AUC ([~]0.71), and Harrells concordance ([~]0.73). Calibration was likewise similar, Brier score ([~]0.09). DiscussionThe RF and RSF models exhibited comparable discrimination and calibration. We conclude that RSF may not always lead to more accurate predictions of outcomes compared to RF. Further examination in different clinical trial cohorts is needed to better understand the context in which adding time into outcomes risk modeling adds value.

Astrocytes play key roles in maintaining brain homeostasis, metabolism, and neurovascular integrity, yet their diversity and age-related modulation remain insufficiently understood, particularly across primate lineages. While rodent studies have generated extensive knowledge, notable species differences highlight the need for comparative analyses in non-human primates. The gray mouse lemur (Microcebus murinus), a small primate widely used in aging research, offers a valuable but underexplored model for studying astroglial aging. In this study, we characterized astrocyte distribution, morphology, and reactivity in 17 mouse lemurs aged 1.0-11.5 years using GFAP and vimentin immunohistochemistry. We identified marked regional and morphological heterogeneity, with dense astrocytic labeling in white matter, hippocampus, and sparse but diverse cortical populations. Distinct astrocyte subtypes--including fibrous, protoplasmic, projection, pial and subpial interlaminar, radial glia-like cells, tanycytes--were documented. Varicosity-bearing processes were common across multiple astroglial subtypes and may indicate altered physiological states. Quantitative analyses revealed pronounced age-related increases in astrocytic reactivity, particularly in white matter and interlaminar astrocytes. Cortical and hippocampal changes were comparatively modest. These findings indicate region-specific astrocytic vulnerability during aging and support the translational value of the mouse lemur for investigating glial aging in primates. Main PointsO_LIThe mouse lemur is the smallest primate on earth with a key role to understand primate brain characteristics. C_LIO_LIWe characterized seven different astrocyte subtypes: from fibrous to primate-specific astrocyte as interlaminar astrocytes in different brain regions of this primate. C_LIO_LIVaricosities were reported in different astrocyte subtypes found close to brain borders. C_LIO_LIMain age-related changes concerned fibrous astrocytes in the white matter and interlaminar astrocytes at the cortical border. C_LI

BackgroundQuantitative genome-wide association studies (GWAS) primarily rely on additive linear models that compare average phenotypic differences between genotype groups. While effective for detecting common variants of moderate effect in large sample sizes, such approaches inherently reduce high-resolution phenotypic data to summary statistics (group averages), potentially limiting the detection of subtle genotype-phenotype relationships. Genomic Informational Field Theory (GIFT) is a recently developed methodology that preserves the fine-grained informational structure of quantitative traits by analysing ranked phenotypic configurations rather than relying solely on mean differences. MethodsWe applied GIFT to genetic and neuropathological data from the Brains for Dementia Research cohort, a well characterised dataset of 563 individuals, and compared its performance with conventional GWAS. Principal component analysis (PCA) derived matrix was used to derive independent quantitative traits linked to from Alzheimers disease (AD) neuropathology measures (CERAD, Thal, Braak staging), with and without inclusion of age at death. Principal component analyses were performed using GWAS and GIFT frameworks on the same filtered genotype dataset. ResultsBoth GWAS and GIFT identified genome-wide significant associations (pvalue<10-6) within the APOE locus (NECTIN2-TOMM40-APOE-APOC1), demonstrating concordance with established AD genetic variants. However, GIFT detected additional significant 19 SNPs beyond those identified by GWAS. Variants associated with AD pathology implicated genes involved in amyloid processing, neuronal apoptosis, synaptic function, neuroinflammation, and metabolic regulation. Notably, GIFT identified 29 loci associated with age at death-related variation that were not detected by GWAS, highlighting genes linked to lipophagy, mitochondrial quality control, sphingolipid metabolism, frailty, and aging-related processes. ConclusionsGIFT recapitulates canonical GWAS findings while uncovering additional biologically relevant associations. By preserving the fine-grained structure of phenotypic data distributions and detecting non-random genotype segregation across ranked trait values, GIFT enables the identification of associations that remained undetected by traditional average-based GWAS approaches. These results demonstrate that rethinking analytical representation, rather than solely increasing sample size, can expand discovery potential of genetic association studies, offering a transparent and complementary framework for quantitative genomics in deeply phenotyped datasets.

Plasma biomarkers of Alzheimers pathology have been studied in relation to cognitive decline and dementia, but no prior study has examined their associations with longevity or healthspan. In this cohort study of older women (N=2,576), we examined plasma biomarkers measured at baseline when women were cognitively unimpaired. We found that plasma biomarkers were associated with both exceptional longevity and healthspan, defined as survival to age 90 without cognitive impairment. Elevated levels of plasma p-tau217 (OR, 0.58; 95% CI, 0.50-0.68), p-tau181 (OR, 0.81; 95% CI, 0.71 - 0.93), NfL (OR, 0.70; 95% CI, 0.60 - 0.82) and GFAP (OR, 0.78; 95% CI, 0.68 - 0.90) were all associated with reduced odds of healthspan; findings survived adjustment for multiple comparisons. These findings suggest that plasma biomarkers may not only reflect ADRD pathology but also systemic aging processes that underlie lifespan and healthspan, underscoring their potential value as novel biomarkers of aging.

Aging is the gradual accumulation of structural and functional changes in an organism over time, including immune remodeling and a progressive increase in basal inflammation, or inflammaging. The mTOR pathway is a central driver of aging-related diseases, such as cancer, chronic inflammation and neurodegeneration; pharmacological inhibition with rapamycin is associated with reduced aged-related morbidity and increased lifespan across species. Nonetheless, concerns remain about the use of rapamycin, a well-established immunosuppressant in transplant medicine, as an anti-aging intervention. Here, we evaluated the impact of prolonged low-dose dietary rapamycin on the aging immune system. Treatment did not significantly alter innate or adaptive immune cell populations, including brain resident microglia; however, it attenuated the age-associated accumulation of IL-17-producing {gamma}{delta} T cells, particularly in the peritoneal cavity. After a peripheral inflammatory LPS challenge, circulating IL-17 levels were significantly reduced and correlated with an attenuation of microglia inflammatory phenotype. These findings suggest that prolonged low-dose rapamycin exposure exerts minor systemic immune changes, while selectively limiting age-related {gamma}{delta} T cell expansion and neuroinflammation associated with systemic inflammation.