Aging is associated with cognitive deterioration accompanied by a reduction in hippocampal neurogenesis. Murine models have been widely used to study aging and age-related cognitive decline, as they recapitulate many of the key features of the degenerative process. Among these, the SAMP8 strain represents a well-established model of accelerated aging, characterized by early-onset and progressive cognitive impairment, Alzheimer's disease-like neuropathology, and an initial increase in hippocampal neurogenesis that ultimately depletes the neural stem cell pool. Notably, most studies using murine models of aging or neurodegeneration have focused on males or mixed-sex cohorts, leaving sex-specific differences in neurogenesis and cognitive decline largely unexplored. Recent evidence indicates that diterpenoid treatment is associated with improved cognitive performance and enhanced neurogenesis in 6-month-old male SAMP8 mice. However, whether females exhibit similar responses remains unknown. In this study, we characterized sex differences in hippocampal neurogenesis in 6-month-old SAMP8 mice and examined potential sex-dependent effects of diterpenoid therapy. Our findings reveal sex-specific differences in physiological and pathological hippocampal neurogenesis and in responsiveness to ER272 treatment. Male SAMR1 mice displayed higher baseline neurogenesis than females, while male and female SAMP8 mice followed distinct neurogenic aging trajectories. ER272 was associated with improved cognitive performance and preservation of multiple neurogenic parameters in males but showed limited effects in females. These results suggest sex-specific mechanisms of brain aging and indicate that mixed-sex analyses may mask biologically relevant differences, highlighting the importance of considering sex in aging studies and therapeutic development.

Early-life nutrition may influence long-term health, but its impact on organ-specific biological aging is unclear. We investigated associations of birthweight and breastfeeding with multi-organ aging and potential mediating pathways in adulthood. Using UK Biobank data, we examined associations of retrospectively reported birthweight (n = 21,446) and breastfeeding history (n = 29,713) with 19 proteomics-derived aging indices, comprising 18 organ-specific indices and one composite index. Multivariable linear regression assessed individual and joint associations, effect modification by sex and socioeconomic factors, and mediation by allostatic load (AL) and C-reactive protein (CRP). Higher birthweight was inversely associated with aging across 11 organ systems (all FDR-adjusted p < 0.05), with strongest associations in the intestine (β = -0.069), esophagus (β = -0.055), and stomach (β = -0.053). Breastfeeding exposure was associated with slower aging of the intestine (β = -0.047) and adrenal gland (β = -0.030), but modestly faster thyroid aging (β = 0.033). The combination of higher birthweight and breastfeeding was associated with favorable aging profiles, particularly in the intestine (β = -0.13), stomach (β = -0.09), and kidney (β = -0.08). Associations were stronger among females and socioeconomically advantaged or healthier-behavior subgroups. AL mediated up to 35.3% of the birthweight-aging association, whereas CRP showed minimal mediation. Higher birthweight and breastfeeding, particularly in combination, produce the most favorable profiles of multi-organ biological aging in adulthood, with AL partially mediating these effects. These findings provide novel evidence that prenatal and postnatal nutrition leave enduring, system-wide imprints on adult aging trajectories.

Vitamin D deficiency has been implicated in biological processes linked to aging and organismal resilience, yet its relationship to long-term systemic aging trajectories remains incompletely characterized. We analyzed longitudinal electronic health record data from two large healthcare systems: Leumit Health Services (LHS), a nationwide Israeli health organization, and TriNetX, a federated US research network. We examined more than 1.67 million serum 25-hydroxyvitamin D [25(OH)D] measurements from over 468,500 adults in LHS (2009-2020). Longitudinal matched analyses compared severe deficiency (< 10 ng/mL) with sufficiency (> 30 ng/mL) in LHS and were externally validated in 223,175 propensity score-matched TriNetX pairs; matched cohorts were approximately 54 years old, 65%-67% female, and followed for up to 10 years. In both populations, severe deficiency was associated with increased risks across multiple aging-related outcomes. All-cause mortality was higher in LHS (adjusted HR 2.57, 95% CI 2.38-2.79) and TriNetX (HR 1.59, 1.55-1.63). To assess modifiability, we modeled vitamin D supplementation longitudinally using pharmacy-dispensed purchases calibrated to predict serum 25(OH)D changes over time. Supplementation was independently associated with dose-dependent reductions across mortality and multiple aging-related outcomes; for > 10 ng/mL-equivalent supplementation, mortality HR was 0.72 (0.68-0.76), while showing no corresponding association for skin malignancy. To strengthen causal interpretation, we additionally implemented inverse-probability-of-treatment-weighted marginal structural Cox models for mortality, which yielded results consistent with conventional adjusted models. Together, these findings support severe vitamin D deficiency as an important and potentially modifiable determinant of systemic aging vulnerability and age-related multimorbidity in human populations.

Epigenetic clocks have emerged as potential biomarkers of aging due to their association with morbidity and mortality. They have recently gained traction as outcome measurements for anti-aging interventions. However, as the number of new epigenetic clocks continues to grow, different clocks may not agree on the effect of an intervention. This raises the question of when researchers can trust epigenetic clock results. In this study, we find that when extending previously published single-clock intervention studies to include additional clock models, no additional clocks reach statistical significance. We then analyze clock behavior across positive control datasets (age-accelerating events) to propose three criteria that increase confidence in a result: (1) reliable PC-based clocks respond, (2) mortality-trained or pace-of-aging clocks respond, and (3) multiple clocks respond in the same direction. To explain why genuine effects would appear across multiple clocks, we perform a simulation study to demonstrate how reliable clocks are more sensitive to true effects, and use longitudinal control datasets to show that reliable clock changes are correlated with each other. We then show examples of interventions that do satisfy these criteria. These findings provide a framework for interpreting epigenetic clock results in anti-aging intervention studies, and suggest that some previously published single-clock findings may warrant reexamination.

Time-restricted feeding (TRF) restricts food intake to daily windows, yet its efficacy against vascular aging and underlying mechanisms remain unclear. Here, we demonstrate that TRF attenuates angiotension II -induced accelerated vascular aging by reshaping gut microbiota, stabilizing microbial diversity, and elevating the Firmicutes/Bacteroidetes ratio. TRF preserved intestinal barrier integrity, upregulated tight junction proteins (Occludin, ZO-1, MUC2), reduced serum lipopolysaccharide, and suppressed systemic inflammation. These benefits translated into alleviated hypertension, aortic stiffness (reflected by pulse wave velocity), and pathological cardiac remodeling. Fecal microbiota transplantation recapitulated these effects, whereas antibiotic-induced microbiota depletion abolished TRF protection; importantly, exogenous acetate supplementation fully restored the phenotypes, establishing acetic acid as the critical downstream mediator. Mechanistically, acetic acid bound to GPR43, inhibited HDAC3, increased H4K8ac acetylation, blocked NLRP3-mediated pyroptosis, and reduced senescence markers (p53, p21, p16) in human umbilical vein endothelial cells, aorta, and heart. 16S rRNA sequencing and short - chain fatty acids metabolomic profiling further identified Limosilactobacillus as the primary acetic acid-producing bacterium enriched by TRF. Together, we uncover a Limosilactobacillus-acetic acid-GPR43/HDAC3/H4K8ac/NLRP3 axis, offering mechanistic insights into TRF as a non-pharmacological strategy against age-related cardiovascular diseases.

Age-associated loss of skeletal muscle mass and function, also known as sarcopenia, is closely linked to mitochondrial dysfunction. In this study, we report that senescent skeletal muscle myoblasts exhibit elevated activity and expression of the enzyme glutaminase (GLS1), which is mediated by p38 MAPK signaling and leads to intracellular urea accumulation that impairs mitochondrial function. Pharmacological inhibition of GLS1 with CB-839 reduced urea levels, restored the expression of electron transport chain (ETC) complexes, and improved mitochondrial function. Consistent with our in vitro findings, CB-839 administration to progeroid mice similarly upregulated ETC complexes and enhanced mitochondrial respiratory capacity in skeletal muscle, leading to improved structural integrity and enhanced muscle strength. Together, these findings suggest that targeting glutamine metabolism via GLS1 inhibition may represent a promising therapeutic strategy to ameliorate age-related skeletal muscle decline by restoring mitochondrial health.

Aging is the predominant risk factor for cardiac dysfunction, driven primarily through a decline in cardiomyocyte and overall myocardial performance. Cellular senescence is becoming increasingly linked to its development, as senescent cardiomyocytes and interstitial cells accumulate with age and exhibit persistent DNA damage, mitochondrial dysfunction, and inflammation that collectively impair ventricular relaxation and contractility. Senolytics, which selectively eliminate senescent cells, effectively clear cardiac senescence and its burden, while aerobic exercise has shown promise as a non-pharmacological intervention capable of modulating senescence. Despite this, neither approach has been evaluated as a long-term preventive strategy or whether combining exercise with senolytics produces an additive effect. We hypothesized that when combined, chronic senolytics and aerobic exercise would produce a synergistic clearance of senescent myocardial cells leading to improved cardiac function. Male and female C57BL/6N mice (12-months-old) were randomly allocated to each group and received their intervention for 9-months: naturally aged (VEH, n = 12), aerobic exercise (EX, n = 11), senolytics Dasatinib + Quercetin (D + Q) (SEN, n = 15) or both combined (SENEX, n = 16). Chronic D + Q, exercise, or both, significantly lowered the proportion of p16+, p21+, and γ-H2AX+ cardiomyocytes and interstitial cells, while improving myocardial performance and diastolic function compared to naturally aged mice. At the whole-heart level, protein expression of p16 and p21 increased with age, but was not altered alongside SASP by any intervention. Collectively, these findings demonstrate that long-term exercise or senolytics limit senescence at the cellular level within the myocardium, and improve ventricular function, positioning exercise or senolytics as promising strategies to mitigate age-related cardiac dysfunction.

Aging is associated with profound alterations in gut microbiota composition and function, including reduced production of short-chain fatty acids (SCFAs), yet it remains unclear whether these age-related microbial changes directly contribute to impaired antiviral defense during influenza A virus (IAV) infection. To address this question, we first characterized age-associated alterations of the gut microbiome and SCFA-related metabolic potential in a murine model of IAV infection. We then used a complementary human senescent lung fibroblast model to determine whether acetate, a major microbiota-derived SCFA, directly modulates antiviral responses in aging-associated lung cells. In old mice, IAV infection was associated with marked microbiota dysbiosis, including reduced abundance of SCFA-producing commensals such as Akkermansia muciniphila and Faecalibaculum rodentium, accompanied by decreased expression of microbial pathways involved in carbohydrate fermentation and acetate production. These findings suggested impaired microbiota-derived metabolic support of antiviral immunity during aging. Based on these observations, mechanistic studies in senescent human lung fibroblasts demonstrated that acetate supplementation significantly reduced viral replication and inflammatory responses. These protective effects were associated with FFAR2/FFAR3 signaling and enhanced histone H3 acetylation, indicating metabolic and epigenetic modulation of the antiviral response. Together, our findings establish a translational link between aging-associated gut microbiota dysfunction and impaired antiviral defense by combining a murine model of aging and influenza infection with mechanistic validation in human senescent lung cells. They identify acetate as a potential mediator of the gut-lung axis and support microbiota-targeted interventions to reduce influenza severity in older individuals.

Senescent cells are a key driver of aging and contribute to many age-related diseases. Senolytics, agents that selectively eliminate senescent cells, offer a promising therapeutic strategy to treat age-related diseases but face significant barriers to clinical translation. Fisetin, a natural flavonoid senolytic, has progressed to clinical trials but is limited by suboptimal efficacy and poor bioavailability. To address these challenges, we developed two novel fisetin-derived flavonoid senolytics, SR29384 and SR31133, using an integrative phenotypic drug discovery approach. These compounds exhibit enhanced senolytic activity, targeting a broad range of senescent cell types, reducing tissue senescence, and improving healthspan-associated parameters in mouse models of aging. Mechanistic investigations combining transcriptomics, machine learning, network pharmacology, and molecular docking revealed that these novel senolytics may target key molecular pathways, including PARP1, CDK2, and possibly BCL-xL to selectively induce apoptosis in senescent cells. These findings provide novel senolytics with high translational potential for clinical applications in promoting healthy aging and treating age-related diseases.

Aging is a major risk factor in the development of type 2 diabetes mellitus (T2DM). With age, pancreatic β-cells undergo functional and cell identity changes that can compromise insulin secretion, thereby contributing to impaired glucose tolerance and T2DM. However, glucose homeostasis also depends on pancreatic α-cells. Excessive plasma glucagon levels, along with impaired regulation of α-cell secretion, are involved in the pathophysiology of T2DM. Despite their importance, the effects of aging on α-cells have been overlooked. In the present study, we analyzed pancreatic α-cells in aged mice with normal insulin sensitivity and in those with peripheral insulin resistance. Regardless of insulin sensitivity, aged mice exhibited hyperglucagonemia and increased glucagon release. Ex vivo, these alterations were associated with increased α-cell mass, higher glucagon content, impaired suppression of glucagon secretion, and endoplasmic reticulum stress. Furthermore, aged mice showed remodeling of islet cellular composition and changes in the spatial organization of α-cells within the islet. Additionally, moderate alterations in α-cell identity were noted. While most of these alterations were already present in aged mice with normal insulin sensitivity, they were generally more pronounced with insulin resistance. Examination of the CORDIOPREV clinical study revealed the presence of hyperglucagonemia in older adults with insulin resistance. Additionally, an increased risk of developing T2DM was also found in older people with higher plasma glucagon levels. The findings described here indicate that aging affects the biology of α-cells and glucagon, positioning them as active players in impaired glucose tolerance and diabetes associated with aging.

Traditionally viewed as a classic sentinel of innate immunity, Toll-like receptor 4 (TLR4) has emerged as a crucial pathological driver within the vascular endothelium, with its identity dictated by cell-type specificity, microenvironmental context, and fluctuating expression levels. This review critically examines the dual functional nature of endothelial TLR4, delineating how it transitions into a primary driver of vascular aging and organ-specific vascular pathologies. The profound spatial, temporal, and cellular heterogeneities of TLR4 signaling expose the fundamental inadequacies of conventional systemic pan-TLR4 blockade, which has repeatedly failed in clinical trials due to severe immunosuppression and metabolic disruptions. To bypass these limitations, we propose a precision senotherapeutic framework utilizing advanced drug delivery systems-such as Vascular cell adhesion molecule-1 (VCAM-1) or E-selectin-targeted nanoparticles and genetically engineered plant-derived exosomes-to compartmentalize TLR4 inhibition within pathologically altered endothelial sub-populations. By shifting the clinical paradigm from indiscriminate receptor suppression to spatiotemporal fine-tuning, this conceptual framework provides a rational blueprint for next-generation anti-aging therapies aimed at restoring vascular homeostasis throughout the aging process.

Transcription factor-based direct conversion of somatic cells represents an interesting avenue for generating induced neural stem cells (iNSCs) from peripheral blood without transit through a pluripotent stage. While this paradigm has been shown to be associated with epigenetic de-aging, the dynamics of this process have remained unclear. Here, we used overexpression of the two reprogramming factors SOX2 and cMYC to generate iNSCs from erythroid progenitors of donors ranging from neonatal to 101 years of age. Using an epigenetic aging clock algorithm, we corroborated our previous finding that iNSCs generated from aged donors show pronounced epigenetic de-aging, preserving around 13% and 5% of the original donor age at low and high passages, respectively. Studying the dynamics of epigenetic de-aging during iNSC conversion across time, we found that this process is largely protracted, continuing for several weeks and even under proliferation-inhibiting conditions. Transcriptomic differences between young and old donor-derived iNSCs dissipate with extended time in conversion, too. Concordant with this observation, established iNSC lines lack age-associated cellular hallmarks, similar to induced pluripotent stem cells and their derivatives. Interestingly, time course analysis of DNA methylation and RNA sequencing data revealed that acquisition of a bona fide NSC signature extends greatly beyond the time point when proliferative PAX6-positive iNSCs emerge. The unexpected slow dynamics of these processes make iNSC conversion an attractive model for dissecting the mechanisms underlying somatic transdifferentiation and epigenetic de-aging.

Aging represents a major contributor to the deterioration of female fertility, with oocyte quality being the central determinant of ovarian aging, a key factor underlying infertility. Although several natural compounds with anti-aging activity have been documented, highly effective strategies to reverse ovarian aging remain elusive. Here, we report that the peptide elamipretide preserves ovarian function and sustains female fertility during maternal aging. We found that elamipretide administration increases litter size in aged mice and ameliorates oocyte quality decline. Metabolomic and transcriptomic profiling revealed substantial restoration of multiple biological processes in aged oocytes after elamipretide injection. Elamipretide improved both nuclear and cytoplasmic maturation of aged oocytes, accompanied by enhanced cytoskeletal dynamics, mitochondrial metabolism, and organelle reorganization. Mechanistically, elamipretide alleviated age-associated oocyte maturation defects through synergistic activation of the vitamin B6-VEGF axis. Furthermore, elamipretide significantly promoted maturation, fertilization, and cleavage of aged human oocytes. Elamipretide treatment also rescued the developmental competence of porcine oocytes under oxidative damage. Collectively, this study identifies a novel peptide therapeutic candidate for aging-related infertility, showing that elamipretide restores the quality of aged oocytes for fertility by coordinately boosting nuclear and cytoplasmic maturation via activation of the VEGF signaling pathway.

Ageing biomarkers quantify molecular, physiological or functional features that vary between individuals as they age and may improve prediction of health outcomes beyond chronological age. Recently, plasma proteomics have been used to estimate the biological ages of 11 human organs. Although accelerated organ ageing is associated with higher mortality risk, systematic benchmarking against established ageing biomarkers is lacking. Here, we pursued two complementary aims. First, we benchmarked proteomic organ clocks against multimodal ageing biomarkers for associations with 16-year all-cause mortality in the Lothian Birth Cohort 1936 (LBC1936) using Cox regression (861 participants; 444 deaths). Biomarkers included the epigenetic clock GrimAge2, telomere length, physical function (grip strength, walk time and respiratory function), neuroimaging and cognitive measures. Among proteomic clocks, accelerated liver (HRperSD [95% CI] = 1.43 [1.30-1.58]), immune (1.42 [1.29-1.57]) and heart (1.38 [1.25-1.53]) ageing were most strongly associated with increased mortality risk. However, older epigenetic age, smaller total brain and grey matter volumes, reduced respiratory function and poorer cognition showed stronger associations with mortality (HRperSD = 1.44-1.62). Second, survival analyses of 9703 plasma protein targets identified 368 candidates associated with mortality, with high-risk proteins enriched for immune functions, and low-risk proteins involved in genomic stability and cellular maintenance. GDF15 (HRperSD [95% CI] = 1.56 [1.42-1.72]), WFDC2 (1.47 [1.33-1.62]) and TIMP1 (1.45 [1.29-1.62]) were the leading proteomic candidates associated with mortality. This study provides a systematic, cross-modal benchmarking of proteomic organ clocks against established ageing biomarkers and identifies proteins and biological functions associated with mortality risk.