Aging

Sepsis can lead to acute respiratory distress syndrome (ARDS) and is associated with a high mortality rate. This study investigated cellular senescence-related genes in sepsis and sepsis-induced ARDS to identify novel biomarkers. Using bioinformatics analyses including WGCNA and machine learning on public datasets, six hub genes (NFIL3, GARS, PIGM, DHRS4L2, CLIP4, LY86) were identified. These genes showed strong diagnostic value and were associated with immune cell infiltration and key pathways. Validation in lipopolysaccharide (LPS)-stimulated neutrophils showed significant upregulation of NFIL3. The findings highlight the role of cellular senescence in pathogenesis and identify promising therapeutic targets for sepsis-induced ARDS.

BackgroundEpigenetic clocks based on DNA methylation (DNAm) are widely used indicators of biological aging; however, most established models have been developed using EPIC arrays and non-Japanese populations. The Methylation Screening Array (MSA), a cost-efficient platform with reduced CpG content, has not been evaluated for its capacity to support biological age estimation and biomarker prediction in Japanese cohorts. MethodsDNAm profiles and clinical laboratory measurements were obtained from 166 Japanese participants for model development; an independent cohort of 48 individuals processed at a separate institute was used for validation. A linear regression model was trained using the Elastic Net method to predict phenotypic age from MSA-derived methylation data, and a two-stage modeling (residual learning) framework integrating EPIC-based clock predictions with MSA-specific residual predictions was evaluated. Additional models were constructed to examine the predictability of 59 clinical biomarkers and their log-transformed variants, including sex-stratified analyses. ResultsThe MSA-based model accurately predicted phenotypic age in the validation dataset; prediction performance improved when the EPIC-based estimates were incorporated through the residual learning framework. Several clinical biomarkers, particularly those related to leukocyte composition and sex hormone regulation, were also predicted from the MSA data, although some markers were strongly affected by sex. Some of the nine constituent phenotypic age biomarkers were not individually predicted. ConclusionsMSA methylation profiles contain sufficient biological information for reliable prediction of epigenetic aging markers in Japanese individuals. These findings demonstrate the feasibility of applying cost-efficient MSA-based DNAm profiling for biological age prediction and provide a methodological foundation for expanding epigenetic biomarker applications in Japan.

BackgroundAging is accompanied by widespread transcriptional remodeling across tissues, yet how aging impacts different categories of tissue-resident macrophages is not well understood. Macrophages are highly specialized innate immune cells shaped by their local microenvironments, suggesting that aging may elicit both shared and niche-specific transcriptional responses. Here, we performed a meta-analysis of publicly available bulk and single cell RNA-sequencing datasets to characterize age-associated transcriptional changes in murine macrophages across tissues and sexes. We curated and uniformly processed 33 macrophage transcriptomic datasets, derived from 10 distinct tissue niches, in male and female C57BL/6 mice using age as the covariate of interest. ResultsThe similarity of differentially expressed aging genes was compared across niches and pathway-level analyses uncovered conserved age-associated functional annotation signatures across macrophage populations, including increased antigen presentation, extracellular matrix remodeling, antioxidant responses, and negative regulation of ferroptosis, alongside decreased Wnt, GTPase, and cell-cycle-related signaling. Transcription factor activity inference analysis identified consistent age-associated activation of stress- and inflammation-related regulators such as AP-1 (Jun), Sp1, and Egr1 across niches. Meta-analysis further defined a core set of 35 genes consistently altered with age across mouse macrophage populations, highlighting coordinated dysregulation of small GTPase signaling as a shared feature of murine macrophage aging. ConclusionsThese findings demonstrate that macrophage aging is shaped by both tissue niche and sex and provides a framework for understanding the transcriptomic signatures of macrophage aging across tissues.

Many overgrowth syndromes are associated with increased risk of tumorigenesis and malignancies. Our group recently identified a frameshift variant in histone reader SPIN4 located on the X chromosome to be a new genetic cause for human overgrowth. In the current study, we investigated the prevalence of malignancies, along with body weight, body length, body composition and bone mineral density, in Spin4 knockout mice at 18 months of age. We found that male mice lacking Spin4 have increased number of tumors and increased body length, while body weight, body composition and bone mineral density were comparable with wild-type mice. We also analyzed publicly available expression data in various types of human cancers and looked for increased or decreased expression of genes that are implicated in overgrowth syndromes and act through epigenetic mechanisms. We found that the expression of SPIN4, EZH2, and DNMT3A to be elevated in many human cancers compared to the corresponding non-malignant tissue samples. Taken together, our current findings confirm that loss of SPIN4 causes overgrowth in mice (in terms of body length) and is associated with increased prevalence in neoplasia; but does not appear to affect adiposity or bone density.

Nucleos(t)ide reverse transcriptase inhibitors (NRTIs) used for HIV treatment and pre-exposure prophylaxis have been proposed as gerotherapeutics based on their capacity to suppress age-associated retrotransposon activity. However, evidence in humans is currently lacking. Here we evaluated DNA methylation-based measures of biological aging in healthy people without HIV (aged 18-50) using samples from two separate randomized, directly observed dosing pharmacokinetic studies of FDA-approved NRTI regimens containing emtricitabine-tenofovir-alafenamide (FTC/TAF;200 mg/25 mg) or FTC-tenofovir-disoproxil fumarate (FTC/TDF; 200 mg/300 mg) for 12 weeks. In the FTC/TAF study (N=36), epigenetic aging measures based on DNA methylation (DNAm) profiling decreased over follow-up, including DunedinPACE (-0.061, p=0.019) and PhenoAge (-6.33, p=0.008), with concordant reductions (p<0.05) across additional systems-specific epigenetic clocks including those estimating brain aging. DNAm-based proxies of inflammatory biomarkers also declined, with significant reductions in epigenetic IL-6 (-0.058, p=0.029) and a trend toward reduced C-reactive protein (-0.231, p=0.059). In contrast, the FTC/TDF study (N=43) showed no significant changes across epigenetic clocks and proxies. These findings are consistent with TAFs more favorable cellular pharmacology compared with TDF and support gerotherapeutic effects of FTC/TAF. Prospective placebo-controlled studies are warranted that integrate clinical pharmacology, direct transposable element readouts, and prespecified geroscience and DNA methylation-based aging endpoints.

Zinc is essential for life, and its regulation is tightly controlled by numerous transporters. As we age, our micronutrient levels, intake, and absorption change. Additionally, senescent cells increase with age and can contribute to the progression of age-related diseases. The study of Zn homeostasis in senescent intestinal cells is a relatively unexplored area that we aimed to investigate. Using two models to induce senescence in intestinal epithelial cells--etoposide treatment and {gamma}-irradiation--we observed that Zn levels increased in the cells, likely due to the upregulation of Zn transporters ZIP4 and ZnT7. This upregulated Zn seems to accumulate in the Golgi apparatus, and when Zn accumulation is blocked through chelation, a rescue effect occurs, marked by a decrease in senescence markers. This research emphasizes the role of Zn in senescent cells and its possible involvement in the development of senescence and the disrupted Zn homeostasis seen with 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.

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.

Background: Ageing is a systems level biological process underlying the onset and progression of multiple chronic disorders. Rather than arising from a single pathway, age related decline reflects interacting disturbances in metabolic regulation, inflammation, nutrient sensing, cellular stress responses, and tissue repair. Although GLP1 receptor agonists, sodium glucose cotransporter2 inhibitors, metformin, and rapamycin are usually evaluated against disease-specific endpoints. Objective: To develop an SBML compliant quantitative systems pharmacology model in which ageing is the primary pharmacological endpoint and to evaluate which combination therapy provides the greatest benefit for both metabolic and ageing related outcomes. Methods: We developed model comprising four layers: a metabolic/pharmacodynamic layer describing weight loss, HbA1c reduction, and nausea with tolerance; a drug layer capturing class-specific effects of GLP1 agonists, sodium glucose cotransporter2 inhibitors, metformin, and rapamycin; an ageing layer representing damage accumulation, repair capacity, frailty, and biological age gap; and a biomarker layer generating trajectories and estimated glucose disposal rate. Calibration was staged across semaglutide clinical endpoints. Bayesian hierarchical meta analysis, global sensitivity analysis, and practical identifiability analysis were used to assess robustness and interpretability. Results: The model reproduced semaglutide efficacy and tolerability dynamics and supported distinct drug-class profiles across metabolic and ageing axes. Rapamycin showed minimal glycaemic effect but emerged as a dominant driver of repair related ageing outcomes. Combination simulations predicted two distinct optima: one favouring metabolic improvement and one favouring ageing related benefit. Conclusion: The model supports the view that metabolic and ageing optimization are mechanistically distinct objectives and that weight loss and glycaemic improvement alone may be insufficient surrogates for health span benefit.

Progenitor cells in aged tissues undergo changes in their microenvironment that may impact their functionality during regeneration. Despite recent advances in understanding the role of adult lung progenitors, the impact of aging on these cells remains unclear. To analyze aging modifications, we used aged wild-type mice of 18-24 months old, and Zmpste24-/- deficient mice, which exhibit an accelerated aging phenotype. A three-dimensional organoid culture system was employed to assess the lung regeneration capacity. Additionally, mouse epithelial cells and fibroblasts were isolated and characterized with senescence and autophagy markers. Our findings revealed that lung epithelial cells from aged mice and Zmpste24-/- mice hold their regeneration capacity, maintaining their phenotype and a healthy cellular state through an increase in autophagy, particularly when co-cultured with healthy fibroblasts. Conversely, cultured fibroblasts from Zmpste24-/- mice show nuclear defects and acquire a senescent phenotype, characterized by mTORC1 activation and reduced autophagy, which in turn impairs organoid formation. Moreover, these progenitor cells become increasingly susceptible to mechanical stress with aging due to reduced nuclear lamins and the Zmpste24 defect. This vulnerability is illustrated by FACS sorting, which can further compromise their regenerative potential. Our results indicate that, in aging, progenitor cells and their fibroblast niche integrate microenvironmental signals that shape cell-cell interactions essential for lung regeneration.

Lung cancer is the leading cause of cancer-related mortality worldwide, predominantly affects older individuals, with non-small cell lung cancer (NSCLC) comprising 85% of cases. Despite advancements in diagnosis and treatment, prognosis for elderly patients remains poor. This study investigates the role of microRNAs (miRNAs) involved in lung cancer, focusing on individuals aged 60 and above. RNA sequencing data from The Cancer Genome Atlas (TCGA) was used to conduct differential expression analysis of miRNA profiles from elderly and senile patient groups. Results showed that out of 1,881 miRNA profiles, 801 were found to be differentially expressed. Filtering for significance identified that 25 miRNAs, with hsa-mir-1911 upregulated and 24, including hsa-mir-196a and hsa-mir-323b found to be downregulated. Studies showed that these miRNAs play roles in apoptosis, senescence, and inflammation. Another Experimental approach in this study, used Machine learning analysis which highlighted key miRNAs, including hsa-mir-181b, hsa-mir-542, hsa-mir-450b, hsa-mir-584, and hsa-mir-21 as crucial in lung cancer biology. Moreover, Functional enrichment analysis revealed their involvement in gene silencing, translational repression, and RNA-induced silencing complex (RISC) regulation. This research identifies the association of miRNAs and aging in lung cancer and finds potential biomarkers that can be helpful in early diagnosis and targets for personalized therapies.

Protein misfolding plays a critical role in aging and disease, yet the involvement of specific proteins in metabolic dysfunction is still poorly understood. Here, we report studies on the development of a Real-time Quaking-Induced Conversion (RT-QuIC) assay to detect misfolded insulin, a peptide hormone required for blood glucose regulation. Although RT-QuIC assays were originally designed to amplify misfolded prion proteins implicated in neurodegeneration, we adapted the method to monitor conformational changes in insulin. We first validated the RT-QuIC insulin assay using recombinant insulin and insulin aggregates recovered from clinical infusion devices. Protein characterization by gel electrophoresis, circular dichroism, and particle size analysis suggests differences in insulin recovered from the infusion device. We then applied the RT-QuIC assay to tissue samples from a mouse model of metabolic disease. This work provides proof-of-concept of a novel assay for studying the role of insulin aggregation in disease progression and aging. The RT-QuIC assay for insulin may also provide new avenues to explore early detection, mechanistic insights, and therapeutic targets of metabolic disorders linked to aging and disease.

Adult survivors of pediatric cancers are at elevated risk for neurocognitive late effects, but how these effects relate to metabolic perturbations in the brain remains unclear. To address this knowledge gap, the present study explored associations between neurometabolite levels and neurocognitive function in adult survivors of Hodgkin lymphoma (HL) and acute lymphocytic leukemia (ALL). Data were collected from a single-center observational study conducted at St. Jude Childrens Research Hospital (SJCRH) between October 2022 and November 2024. Adult survivors of HL (N=11 [5 females]; [&ge;]5 years post-diagnosis; mean [SD] current age 34 [9.5] years) and ALL (N=24 [16 females]; [&ge;]5 years post-diagnosis; current age 40 [12.6] years) and community controls (N=35 [17 females]; current age 40 [11] years) completed standardized neurocognitive tests of memory, attention, executive function, and processing speed. Participants also underwent proton magnetic resonance spectroscopy (1H MRS) to quantify neurometabolite levels in the left dorsolateral prefrontal cortex (dlPFC), left hippocampus, and left cerebellum. Analyses used regression models to examine differences in the slope of the relationship between neurometabolite and neurocognitive function or between neurometabolite and age. When comparing HL survivors vs controls, significant interactions were identified for group x age on the ratio of myo-inositol to N-Acetyl aspartic acid (mI/NAA; p=0.007) and group x Gamma-Aminobutyric Acid (GABA) on processing speed (p=0.04) in the left dlPFC. When comparing ALL survivors vs controls, significant interactions were identified for group x myo-inositol on verbal fluency in the left hippocampus (p=0.01) and group x GABA on cognitive flexibility in the left cerebellum (p=0.01). These preliminary findings suggest that neuroinflammation may be a mechanistic underpinning of age-associated neurocognitive impairment in pediatric cancer survivors.

Sirtuin 6 (SIRT6) is an important regulator of DNA repair, metabolism, chromatin maintenance and longevity. SIRT6 Serine 10 phosphorylation controls SIRT6 recruitment to the sites of DNA damage. To explore the effect of SIRT6 Serine 10 phosphorylation on lifespan, we generated two SIRT6 mutant mouse strains: phospho-null S10A and phosphomimetic S10E. The S10E mutant mice demonstrated enhanced DNA repair capacity, elevated LINE1 expression and reduced lifespan in male mice compared to the wild-type and S10A mice. This result suggests that SIRT6 S10E mutation enhances DNA repair capacity at the expense of reduced LINE1 silencing leading to shorter lifespan. While both SIRT6 functions in DNA repair and chromatin maintenance are important for longevity, our results suggest that when the balance between these functions is shifted, diminished of LINE1 control has a stronger impact on lifespan than enhanced DNA repair.

{Delta}133p53 is a naturally occurring isoform of the human p53 protein that inhibits p53-mediated cellular senescence. We recently reported that transgenic expression of this senescence-inhibitory p53 isoform counteracts aging-associated pathological changes and extends lifespan in progeria model mice (heterozygous LmnaG609G/+). The anti-aging effect of {Delta}133p53 was attributed in part to reduced levels of the proinflammatory cytokine IL-6. To comprehensively profile {Delta}133p53-induced changes in cytokines and chemokines, we in this study performed a Luminex-based multiplex quantitative assay of mouse sera collected from transgenic {Delta}133p53-expressing LmnaG609G/+ mice and non-expressing controls. This assay not only confirmed the {Delta}133p53-mediated repression of IL-6 but also showed that {Delta}133p53 reduced the levels of CXCL1 (also known as KC), IL-1, and CXCL10 (also known as IP-10). Among these factors, we further characterized CXCL10, which has not previously been associated with progeria in mice or humans. Consistent with reduced serum CXCL10 levels, both young (15-week-old) and old (10-month-old) {Delta}133p53-expressing LmnaG609G/+ mice showed reduced Cxcl10 expression, compared with age-matched non-expressing controls, in the liver, spleen, and brain, major organs known to produce CXCL10. In naturally aged wild-type mice (2-year-old), Cxcl10 expression was also significantly repressed by transgenic {Delta}133p53 in the spleen and brain. Analysis of gene expression datasets from human tissues demonstrated an inverse association between CXCL10 and {Delta}133p53 levels, suggesting physiological relevance to human aging. This study defines CXCL10 as a proinflammatory chemokine elevated in both accelerated and natural aging and as a potential target of the anti-inflammatory activity of {Delta}133p53.

Due to aging, the efficiency of kidney function begins to decrease. Dysfunction in mitochondria and their cristae is a hallmark of aging. Therefore, age-related decline in kidney function could be attributed to changes in mitochondrial ultrastructure, increased reactive oxygen species, and alterations in metabolism and lipid composition. We sought to understand how mitochondrial ultrastructure is altered over time in tubular kidney cells. A serial block facing-scanning electron microscope and manual segmentation using the Amira software were employed to visualize murine kidney samples during the aging process at 3 months (young) and 2 years (old). We found that 2-year mitochondria are more fragmented with many uniquely shaped mitochondria observed across aging, concomitant with shifts in ROS, metabolomics, and lipid homeostasis. Furthermore, we demonstrate that the mitochondrial contact site and cristae organizing system (MICOS) complex is impaired in the kidney during aging. Disruption of the MICOS complex resulted in altered mitochondrial metabolic function and increased ROS levels. We found significant, detrimental structural changes in the mitochondria of aged kidney tubules, suggesting a potential mechanism underlying the increased frequency of kidney disease with aging. We hypothesize that disruption of the MICOS complex exacerbates mitochondrial dysfunction, creating a vicious cycle of mitochondrial degradation and oxidative stress, which impacts kidney health. Impact and ImplicationsDue to aging, the efficiency of kidney function begins to decrease, and the risk of kidney diseases may increase; however, the specific regulators of mitochondrial age-related changes are poorly understood. This study demonstrates that the MICOS complex may be a target for mitigating age-related mitochondrial changes. The MICOS complex is associated with oxidative stress and calcium dysregulation, which also arise in many kidney pathologies. HighlightsO_LIAging alters the MICOS mRNA levels and disease markers. C_LIO_LIAging reduces cristae architecture, mitochondrial volume and complexity in murine kidney ultrastructure C_LIO_LIReducing MIC60 and CHCHD6 lowers Ca2+ uptake and retention and induces oxidative stress in HEK cells. C_LIO_LIMetabolomic Profiling revealed that NAD+ and amino acid metabolism were altered in aged kidneys. C_LIO_LIMICOS deficiency alters the reduced basal, ATP-linked, maximal capacity and spare capacity. C_LIO_LIDecreased modeled expression of CHCHD6 in individuals of European genetic ancestry is linked to chronic kidney disease, whereas decreased modeled expression of OPA1 in individuals of African genetic ancestry is associated with chronic kidney disease. C_LI Graphical AbstractKidney aging causes a decline in the MICOS complex, concomitant with metabolic, lipidomic, and mitochondrial structural alterations. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=142 SRC="FIGDIR/small/598108v3_ufig1.gif" ALT="Figure 1"> View larger version (53K): org.highwire.dtl.DTLVardef@80123aorg.highwire.dtl.DTLVardef@2c9f1eorg.highwire.dtl.DTLVardef@1827e26org.highwire.dtl.DTLVardef@280f4f_HPS_FORMAT_FIGEXP M_FIG C_FIG

DNA methylation is an established biomarker of human ageing, and analysing CpGs grouped by transcript as functional units may reveal new insights into the processes of ageing. In this study, we analyzed the GSE87571 dataset (714 samples from 14-94 years) to assess the relationship between transcript-level methylation profiles and chronological age in human blood. This approach led to the creation of Epitage, a curated set of 48 transcripts from 13 genes identified through machine learning as having methylation profiles that strongly correlate with age (R2 [&ge;] 0.8). This analysis highlighted transcripts from the genes KCNS1, SPTBN4, and VTRNA1-2, which have been only rarely mentioned as age-related methylation markers in humans, suggesting them as underexplored candidates for future investigation. In addition, the list includes genes already implicated in aging or related pathways, such as ELOVL2, FHL2, KLF14, TRIM59, MIR29B2CHG, CALB1, OBSCN, PRRT1, OTUD7A, and SYNGR3. To validate models efficiently while ensuring reproducibility, we developed ugPlot, an open-source R package with a graphical user interface (GUI) that automates routine steps for training and testing hundreds of machine-learning models. The tool also streamlines dataset import and manipulation, reducing human error and generating publication-ready plots. Epitage thus provides a focused and accessible starting point for experimental and translational studies into the roles of DNA methylation and transcript regulation in human ageing.

BackgroundGeroprotective interventions, including the mTOR inhibitor rapamycin, slow aging in preclinical models. Translation to humans remains challenging because clinical trials require endpoints detectable within feasible timeframes. Multi-modal in vivo imaging could address this limitation by enabling simultaneous assessment of age-related pathology across multiple organ systems, but its feasibility in clinical trials is uncertain. ObjectiveTo evaluate the feasibility of deploying a multi-modal, multi-organ imaging battery in a geroprotective intervention trial of rapamycin and to collect exploratory efficacy data across multiple domains of age-related pathology. MethodsIn a single-center, open-label, single-arm pilot trial, 14 participants with early-stage Alzheimers disease (MCI or mild dementia; Montreal Cognitive Assessment [&ge;]18; amyloid-positive) received oral rapamycin 7 mg once weekly for 26 weeks. Participants underwent baseline and end-of-treatment imaging including retinal optical coherence tomography (OCT); [18F]FDG positron emission tomography/computed tomography (PET/CT) of the head, thorax, and lower spine; dentomaxillofacial MRI; and cardiac MRI with stress perfusion and arterial pulse wave velocity. Feasibility outcomes included completion rates and technical or logistical barriers. Exploratory pre-post changes were assessed using paired t-tests. ResultsOf the 14 enrolled participants, 13 completed follow-up imaging. Among these, completion was 100% for OCT, [18F]FDG PET/CT, and dentomaxillofacial MRI. Cardiac MRI and pulse wave velocity were completed in 69% (9/13), primarily limited by scanner access during a healthcare worker strike. No imaging-related adverse events occurred. Exploratory analyses showed nominally significant pre-post increases in cardiac output (p=0.017), late diastolic (A-wave) kinetic energy (average: p=0.044; peak: p=0.024), left retinal ganglion cell layer thickness (p=0.044), and optic nerve head [18F]FDG uptake (p=0.040). Bone mineral density showed no significant pre-post changes, while muscle cross-sectional area decreased numerically but not significantly (p=0.058). In exposure-response analyses, higher rapamycin blood concentration was significantly correlated with greater skeletal muscle density (r=0.64, p=0.035) and, albeit not significantly, smaller loss of cross-sectional area (r=-0.53, p=0.097). ConclusionsA multi-modal imaging battery spanning several organ systems was successfully integrated into a clinical trial, with high completion rates for most modalities. Logistical constraints were the primary barriers affecting cardiac measures. These findings inform the design of future randomized trials of geroprotective interventions, where such imaging batteries may help detect changes in age-related pathology over relatively short timeframes.

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.

Frailty is a prevalent geriatric syndrome, and the shortage of objective biomarkers restricts its early diagnosis and intervention. This study aimed to identify robust molecular signatures and diagnostic markers for frailty using bioinformatics analyses of multiple independent datasets. Two transcriptome datasets (GSE144304, n=80; GSE287726, n=70) were obtained from the GEO database. We performed differential gene expression analysis, GO, KEGG and GSEA enrichment, and machine learning (70% training / 30% validation) to screen and validate core biomarkers. Numerous shared differentially expressed genes were identified. Vitamin D metabolism, ABC transporter, and inflammatory/immune pathways were consistently enriched and confirmed by GSEA. Machine learning models based on these signatures showed favorable diagnostic performance. Our study demonstrates that vitamin D metabolic disorders and chronic inflammation are core molecular features of frailty. The identified biomarkers provide new strategies for basic research, early clinical diagnosis, and therapeutic target development for frailty.