Sepsis remains a leading cause of mortality among older hospitalized adults. Readily available biomarkers may improve early risk stratification in this vulnerable population. We evaluated the prognostic value of the neutrophil-to-lymphocyte ratio (NLR), C-reactive protein-to-albumin ratio (CAR), and estimated glomerular filtration rate (eGFR), and developed a composite score (NCe) integrating these parameters. This retrospective cohort study included 846 patients aged ≥75 years hospitalized with sepsis or septic shock within the Report-AGE project. NLR, CAR, and eGFR were assessed at admission. Multivariable Cox proportional hazards models were adjusted for age, sex, transaminases, RDW-CV, Charlson Comorbidity Index, polypharmacy, and functional impairment. Overall, 258 patients (30.5%) died during hospitalization. Non-survivors had higher NLR and CAR values and lower eGFR than survivors. The highest NLR tertile was independently associated with mortality, whereas CAR showed a weaker association. The NCe score demonstrated a graded increase in mortality risk across categories, with Kaplan-Meier analyses showing progressively lower survival as the score increased. In conclusion, routine inflammatory and renal biomarkers are associated with mortality in older adults with sepsis. Their integration into the NCe score may provide a simple and widely accessible approach to mortality risk stratification in older adults with sepsis, warranting further prospective validation.

Liver dysfunction rates increase markedly with ageing causing the plasma concentrations of toxic endogenous metabolites to rise. We demonstrated that brief exposure of HepG2 cells in vitro to a liver-derived toxic metabolite cocktail triggers a distinct state of cellular senescence termed senescence induced by liver toxins (SILT). SILT combines classical features of senescence (loss of proliferative capacity, proinflammatory changes, senescence associated β- galactosidase reactivity and cyclin dependent kinase inhibitor upregulation) with a broader loss of essential hepatocyte functions. Immortalised cell lines are valuable models for primary hepatic function but also show important physiological differences. We have extended our analysis to primary hepatocytes and have found that both human and porcine liver cells undergo SILT in vitro when exposed to the concentrations of endogenous toxins typical of liver disease. As in HepG2 cells, SILT in primary hepatocytes was accompanied by loss of albumin production (as measured by ELISA) and urea synthesis (measured biochemically) but was reversible by 5µM resveratrol in a species- and function-dependent manner. Deeper transcriptomic profiling of SILT revealed the activation of stress and inflammatory pathways combined and repression of hepatocyte metabolic programmes. Gene Set Enrichment Analysis demonstrates that the SILT is present in vivo in multiple reference transcriptomic datasets derived from diseased, but not healthy liver. This is consistent with the presence of a population of SILT hepatocytes among the senescent cells found in the ageing organ in vivo. Thus, SILT may contribute to the ultimate failure of liver function which may potentially be delayed by resveratrol treatment.

Recently, the consumption of various forms of the nutritive amino acid lysine (e.g., nutraceuticals and dietary supplements) has increased, particularly among the elderly, as it cannot be synthesized by the human body and plays a crucial role in several cellular physiological processes, including intestinal calcium and iron absorption, proteinogenesis, and fatty acid metabolism. However, the biochemical and immunological events that occur within the eukaryotic host-microbe-phage-nutrition interaction, especially when high amounts of lysine are consumed in nutraceutical or dietary supplement form by the elderly due to age-related requirements, as well as the impact on gut bacteria-derived metabolites, have not yet been fully studied. We hypothesized that (1) within an infectious-inflamed digestive milieu, the metabolism of excess extracellular lysine differs between young and senescent digestive cells, and (2) phages within the milieu exhibit alterations in host-microbe cometabolite signal profiles. To address this, we examined how gut microbes and phages, key regulators of eukaryotic host physiology, influence the immunometabolism of excess lysine. By combining two models of young and senescent digestive cells, the pathogenic P. aeruginosa PAO1, the Pseudomonas phage KPP22, and the anti-inflammatory bacterium Intestinimonas butyriciproducens, and simulating the pathogenesis of the interactive process of excessive lysine ingestion, we developed a five-way screening approach to explore key cell readouts, including viability, integrity, and function of the epithelial barrier, as well as cellular immunometabolic responses to exogenous lysine supplementation in cultures under infectious inflammation. Our findings are consistent with the possibility that host-microbe-microbe interactions involving lysine utilization and cross-feeding may influence the effects of lysine supplementation. These effects, whether beneficial or detrimental, can depend on the bacterial community, including the presence of pathogenic or potentially beneficial bacteria, interactions with intestinal phages, and the physiological conditions and metabolic requirements of the host and individual microbial taxa.

Taste dysfunction is commonly associated with aging and accompanied by morphological and molecular alterations in the tongue epithelium. To investigate the mechanisms underlying this phenomenon, we utilized Klotho-deficient (Kl -/-) mice, a model of accelerated aging. The tongue epithelium of Kl -/- mice showed altered muscle organization and increased clear spaces within the muscle compartment. The minor salivary glands displayed acinar cell atrophy. Notably, compared with WT, Kl -/- mice presented a reduced taste bud diameter and decreased expression of key taste receptors, as well as type II taste cells. Importantly, immunohistochemical and western blot analyses revealed decreased expression of SOX2 in taste buds and tongue epithelium. Overexpression of SOX2 significantly upregulated PLCB2, which plays roles in taste bud cell differentiation and function. Conversely, siRNA-mediated knockdown of SOX2 resulted in reduced expression of taste-related genes (Keratin 8, PLCB2, Taste receptors) and decreased expression of NTF3 and BDNF, neurotrophic factors involved in sensory-neural maintenance. Furthermore, SOX2 directly regulated the promoter activity of NTF3, suggesting that SOX2 contributes to taste bud maintenance through transcriptional regulation of NTF3. Together, these findings suggest that altered SOX2 expression is associated with changes in taste-associated proteins and neurotrophic-factors expression in the aging Kl -/- tongue.

Aging is associated with impaired lung repair and increased susceptibility to injury, yet the mechanisms underlying age-associated dysfunction of alveolar type II (AT2) cells remain poorly understood. Although cellular senescence is a hallmark of aging, emerging evidence suggests that aging is also characterized by progressive loss of cellular resilience, rendering epithelial cells increasingly vulnerable to stress. Here, we show that AT2 cells in aged lungs remain predominantly non-senescent under basal conditions but exhibit increased susceptibility to stress-induced senescence. This stress-vulnerable state is accompanied by impaired mitochondrial homeostasis, excessive mitochondrial reactive oxygen species accumulation, and mitochondrial dysfunction. We identify the RNA-binding protein cytoplasmic polyadenylation element-binding protein 4 (CPEB4) as a critical regulator of mitochondrial adaptation in AT2 cells. CPEB4 deficiency does not induce overt senescence under basal conditions but markedly exacerbates stress-induced senescence both in vitro and in vivo. Mechanistically, CPEB4 sustains expression of tumor protein p53-inducible nuclear protein 2 (TP53INP2) through post-transcriptional regulation, thereby preserving mitochondrial homeostasis during stress. Restoration of TP53INP2 partially rescues mitochondrial dysfunction and attenuates senescence-associated phenotypes in CPEB4-deficient cells. Collectively, our findings identify a CPEB4-TP53INP2 axis that preserves mitochondrial adaptability and limits stress-induced senescence, providing mechanistic insight into how aging progressively compromises epithelial stress resilience.

Progressive mitochondrial dysfunction coupled with calcium dyshomeostasis is a hallmark of aging and neurodegenerative conditions, yet the molecular links to cognitive decline remain unclear. Moreover, although sex differences in susceptibility to neurodegeneration are well recognized, their molecular basis remains poorly defined. In our previously engineered mouse model, systemic depletion of Tusc2 (Fus1), a mitochondrial calcium-regulatory protein, accelerates aging and recapitulates key features of human aging, including sex-specific cognitive decline. Here, we identify Tusc2 as a key modulator of hippocampal (HP) resilience to aging. To define the impact of Tusc2 loss on molecular determinants of cognition, we profiled HP transcriptomes in both sexes and proteomes in males at 4 months of age, when sex-specific differences in cognitive behavior first emerge. Male knockout HP exhibited broad mitochondrial dysfunction, including suppression of oxidative phosphorylation (OxPhos) proteins, activation of the ATF4 branch of the integrated stress response (ISR), and coordinated downregulation of translational, proteasomal, and synaptic pathways. These molecular alterations were accompanied by increased protein aggregate size, consistent with impaired proteostatic capacity, and reduced PSD-95 neuropil intensity, indicative of compromised synaptic integrity in the HP. In contrast, female knockout HP exhibited comparatively modest transcriptional alterations and preferential activation of adaptive ATF6-associated unfolded protein response (UPR) pathways, consistent with a protective response that may be influenced by estrogen signaling, sex chromosome complement, epigenetic regulation, and other sex-dependent mechanisms. Comparative analysis with aging human HP datasets revealed significant and broad overlaps, suggesting that TUSC2deficiency recapitulates key molecular features of human brain aging. Together, these findings identify TUSC2 as a principal regulator of mitochondrial calcium homeostasis that contributes to maintenance of proteostatic and synaptic integrity of the HP during aging, and reveal marked sex differences in mitochondrial stress resilience. These results establish Tusc2 deficiency as a mechanistically defined model for investigating early, potentially reversible stages of mitochondrial and proteostatic decline in brain aging.

Hutchinson-Gilford progeria syndrome (HGPS) is a fatal laminopathy caused by an LMNA mutation that generates progerin, a permanently farnesylated, truncated form of prelamin A. Although progerin's structural effects are well established, prior reviews have largely cataloged its downstream consequences, genome instability, proteostasis failure, inflammation, stem-cell dysfunction and matrix remodeling, as parallel, largely independent processes. Here, two decades of mechanistic evidence are reorganized into a single evidence-ranked hierarchy spanning four interconnected levels of homeostasis, nuclear, cellular, tissue and organismal, that explicitly separates established mechanisms from inferred cross-scale links. Progerin perturbs post-mitotic nuclear reassembly, but several defining abnormalities emerge or intensify during interphase and across successive cell generations, indicating progressive maintenance failure rather than a purely static structural model. Nuclear dysfunction is associated with impaired proteostasis, stress adaptation and lineage competence; these cellular defects can be amplified by extracellular-matrix remodeling, chronic inflammation, and reduced regenerative capacity. Evidence is strongest for nuclear and cellular mechanisms, whereas a continuous nucleus-to-organism sequence remains an integrative, testable model. When fragmented mechanisms are ordered across biological scales, this framework helps explain disease latency, tissue selectivity, partial reversibility, and the rationale for combination therapy. Lonafarnib, proteostasis-directed interventions, JAK-STAT inhibition and genome-, RNA-, and progerin-directed strategies are therefore considered complementary approaches acting at distinct levels of the hierarchy. HGPS is not a replica of physiological aging, but a genetically defined system that reveals how persistent nuclear stress can progressively erode conserved adaptive networks.

The functional integrity of the medial prefrontal cortex (mPFC) depends on the accurate integration of synaptic inputs via the dynamic interplay between pyramidal cells (PCs) and GABAergic interneurons. In this comparative study, we report how aging alters the electrophysiological profiles of layer 5 PCs and local interneurons in the rat mPFC. Relative to 2-month-old rats, 24 ± 2-month-old acute brain slices containing the prelimbic area of mPFC exhibited changes in the passive and active membrane properties governing neuronal excitability. Whole-cell patch-clamp recordings showed reduced firing frequency in PCs and increased firing frequency in interneurons. Analysis of ionic conductances revealed decreased voltage-gated sodium current amplitude in PCs, whereas interneurons exhibited decreased potassium current amplitudes. Extracellular recordings further identified network-level impairments with aging, including reduced population spike amplitude and diminished gain, indicating decreased synaptic recruitment. Short-term plasticity was selectively affected: at 10 and 30 Hz, aging increased the decay time constant and attenuated synaptic depression by preserving higher response amplitudes, while responses to 50 Hz stimulation remained unchanged. By recording both neuronal types within the same experimental and anatomical framework, this study enabled a unified interpretation of how cell-type-specific aging adaptations emerge within a shared microenvironment. Overall, aging differentially disrupts excitability and ionic mechanisms in pyramidal and interneuron populations, leading to impaired synaptic integration and altered short-term plasticity in mPFC microcircuits. Collectively, these findings suggest that disrupted synaptic integration and intrinsic neuronal function in the aged neocortex may contribute to age-related cognitive decline.

Reproductive history has implications for long-term health, with menopausal timing and parity associated with chronic disease risk. DNA methylation (DNAm) clocks are biomarkers of aging and estimate epigenetic age acceleration (EAA) in reproductive tissues and systemically. DNAm clocks provide mechanistic insight into how reproductive history relates to aging. This study aimed to identify associations between reproductive history and DNAm clocks. Twenty-nine studies comprising 550,550 participants (median mean age=35.4 (IQR: 30.3-62.7) years, 100% female) assessing associations between reproductive history and EAA were included. Across studies, preterm birth and earlier age at menopause was consistently associated with higher EAA, yet age at menarche, pregnancy complications, and adverse birth outcomes showed mixed findings. Meta-analysis of cross-sectional studies showed each one-year earlier age at menopause was significantly associated with higher EAA, strongest in GrimAge (n = 5920, β=-0.08 years, 95% CI: -0.11, -0.05). No relationship was found between age at menarche and EAA in any DNAm clocks. Meta-analysis of parity showed associations with EAA using PhenoAge (n = 4508, β=0.13 years per delivery, 95% CI: 0.04, 0.21). These findings highlight that aspects of reproductive history are cross-sectionally associated with higher EAA, particularly measured with 2nd generation DNAm clocks (PhenoAge, GrimAge).

Aging is characterized by a progressive decline in cellular homeostasis that ultimately compromises tissue integrity, regenerative capacity, and organismal function. Among the molecular processes increasingly recognized as central regulators of aging, intracellular Ca[2+] signaling has emerged as a major determinant of metabolic adaptation, stress responses, inflammation, and cell fate. Ca[2+] controls essential biological functions in virtually every tissue. Importantly, the remarkable versatility of Ca[2+] signaling depends on the precise spatial and temporal coordination of channels, pumps, exchangers, buffering proteins, and organelle contact sites that together generate highly organized intracellular Ca[2+] microdomains. During aging, the quality of this signaling progressively deteriorates. Altered activity of plasma membrane channels, defective endoplasmic reticulum (ER) Ca[2+] handling, impaired mitochondrial buffering, oxidative stress, and chronic inflammation collectively destabilize intracellular Ca[2+] homeostasis. These alterations converge on mitochondrial dysfunction, one of the central hallmarks of aging, leading to bioenergetic decline, excessive reactive oxygen species production, cellular senescence, and impaired tissue adaptation. In the nervous system, disrupted Ca[2+] signaling contributes to synaptic dysfunction, neuroinflammation, and neuronal vulnerability associated with cognitive decline and neurodegenerative disease. In skeletal muscle, defective Ca[2+] handling impairs excitation-contraction coupling, mitochondrial metabolism, and regenerative capacity, thereby promoting sarcopenia and motor decline. In this review, we discuss how aging remodels the cellular Ca[2+] signaling toolkit across neuronal and muscular systems, with particular emphasis on mitochondrial dysfunction, senescence and inter-organelle communication. Finally, we examine therapeutic strategies aimed at restoring Ca[2+] signaling fidelity as potential interventions to preserve tissue function and extend healthspan.

Fasting is an effective physiological intervention eliciting global and cellular adaptations that can improve healthspan and lifespan. In addition to its metabolic effects, fasting is a state of modulation of aging-associated processes/adaptive cellular responses that drives an intense epigenomic and transcriptional remodeling response which preserves functional capacity during aging. Nutrient deprivation elicits the activation of evolutionarily conserved nutrient-sensing pathways including AMPK and sirtuins, which can modulate chromatin accessibility and transcriptomic programs. These changes impact critical epigenetic processes like histone modifications, DNA methylation, and non-coding RNAs which underline adaptive transcriptional programs that drive cellular maintenance, autophagy, and stem cell function. Recent studies also suggest that fasting-mediated epigenomic flexibility may help reduce age-related epigenetic drift, dampen chronic inflammation, and cellular adaptation/maintenance of cellular function across various tissues. Notably, these processes may link fasting to both lifespan and age-related disease resistance, including metabolic disorders, neurodegeneration, and cancer. This review aims to synthesize current knowledge on how fasting modulates epigenomic landscapes/influences epigenomic regulation and transcriptome to impact aging and healthspan. We highlight key molecular pathways, cell-type specific effects, and emerging translational opportunities, while also discussing challenges, limitations, and open questions that need to be addressed to leverage fasting-inspired approaches for healthspan to promote healthy aging.

Premature ovarian failure (POF) is closely linked to ovarian granulosa cell (OGC) senescence and cell cycle arrest. This study explored the role of the miR-322/Klotho axis in OGC aging. Using a cyclophosphamide-induced mouse model and cultured OGCs, we found Klotho significantly downregulated in POF, inversely correlating with elevated miR-322 and senescence markers p16, p21, and p53. Luciferase assays confirmed Klotho as a direct miR-322 target. miR-322 overexpression induced G0/G1 and G2/M phase arrest and OGC senescence by silencing Klotho, while miR-322 inhibition partially rescued the POF phenotype. miR-322 knock-in mice exhibited reduced ovarian weight, increased follicular atresia, and altered E2/FSH levels, mimicking clinical POF. Mechanistically, the miR-322/Klotho axis modulated cell cycle regulators, upregulating CHK1 and downregulating CDC25A, CDK2, and Cyclin A/E. Thus, miR-322 promotes OGC senescence and POF by targeting Klotho to activate cell cycle inhibition pathways, identifying this axis as a critical epigenetic regulator of ovarian aging and a potential therapeutic target.