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Multi-omic underpinnings of heterogeneous aging across multiple organ systems.

Aging is the main determinant of chronic diseases and mortality, yet organ-specific aging trajectories vary, and the molecular basis underlying this heterogeneity remains unclear. To elucidate this, we integrated genomic, epigenomic, transcriptomic, proteomic, and metabolomic data, employing post-genome-wide association study methodologies to systematically investigate the molecular mechanisms of nine organ-specific aging clocks and four blood-based epigenetic clocks. We uncovered genetic correlations and specific phenotypic clusters among these aging-related traits, identified prioritized genetic drug targets for heterogeneous aging, and elucidated downstream proteomic and metabolomic effects mediated by heterogeneous aging. We constructed a cross-layer molecular interaction network of heterogeneous aging across multiple organ systems and characterized detectable biomarkers of this heterogeneity. Integrating these findings, we developed an R/Shiny-based framework that provides a comprehensive multi-omic molecular landscape of heterogeneous aging, thereby advancing the understanding of aging heterogeneity and informing precision medicine strategies to delay organ-specific aging and prevent or treat its associated chronic diseases.

Aging

Mitochondrial Haplotype Shapes the Trajectory of Ovarian Aging in Genetically Heterogeneous Rats.

Ovarian aging leads to permanent reproductive senescence and systemic hormonal changes that predispose women to age-associated comorbidities. Despite these observations, the intrinsic mechanisms driving age-related ovarian decline are poorly defined. Mitochondrial DNA (mtDNA) mutations and instability are strongly associated with aging; however, it remains unknown if naturally occurring mitochondrial genetic variation influences the trajectory of ovarian aging. To address this, we compared two genetically heterogeneous rat cohorts (OKC-HETB and OKC-HETW) that differ in mitochondrial haplotype on a randomized but equivalently distributed nuclear background. The OKC-HETW haplotype was associated with accelerated loss of primordial follicles and pathological remodeling marked by fibrosis, macrophage infiltration, and multinucleated giant cells. These tissue-level pathologies were paralleled by mitochondrial dysfunction, characterized by decreased respiratory complex activity, ATP production, and mtDNA copy number. Mechanistically, we identified a haplotype-specific defect in mitochondrial genome maintenance. Although TFAM expression was normal, and total TFAM protein was elevated, OKC-HETW ovaries showed reduced mitochondrial TFAM abundance, TFAM-mtDNA binding, and TOMM20, suggesting that impaired TOMM20-mediated import is associated with compromised mitochondrial genomic stability. Longitudinal transcriptomic and proteomic analyses further indicate that mitochondrial haplotype influences the rate of ovarian aging, with OKC-HETW ovaries showing accelerated activation of inflammatory and fibrotic pathways alongside suppressed proteostasis and mitochondrial function. These defects corresponded to impairments in ovulation and a trend toward worsening oocyte quality. Collectively, our findings identify mitochondrial haplotype as a heritable modifier of ovarian aging rate that acts in concert with the nuclear genome, and a putative target for preserving ovarian function and female healthspan.

Animals

Age-related changes of thymus--morphological and functional aspects.

The thymus involutes progressively throughout life, beginning at around the sexual maturation. In long-lived BC3F1 hybrid mice, the thymic capacity to induce T cell differentiation begins to decline earlier than the onset of thymic involution, although the magnitude of the decline is different by the subpopulation of T cells. Morphologically, the most active secretory structure seems to be limited exclusively to the neonatal thymus and certain structural changes, reflective of a decline in secretory function, can be detected early in life and they become more pronounced with age. Heterogeneity of thymic epithelial cells is suggested by the facts that age-related and radiation induced decline of immune activities are different in degree by subpopulation of T cells, and the concept is also supported from a morphological viewpoint. It is thus apparent that age-related thymic involution results in decrease of recruitment of fresh capable T cells and increase of old exhausted T cells, eventually bringing about T cell insufficiency in the aged individuals. Such an impaired immune function in the aged mice can be effectively restored by the combined grafting of young bone marrow and newborn thymus, and the thymus is apparently the most limiting factor in the aged. The biological signficance of age-related thymic involution is also discussed.

Aging

Longevity of cardiac and skeletal muscle proteins is dependent on tissue and subcellular compartmentation patterns.

Myocytes are exceptionally long-lived cells that must maintain proteome integrity over decades while adjusting for changes in functional output and metabolic demand. We used in vivo stable isotope labeling combined with mass spectrometry proteomics and correlated multi-isotope imaging mass spectrometry to quantify and visualize protein turnover across cardiac, fast-twitch, and slow-twitch skeletal muscles, creating a resource of hundreds of individual protein turnover rates from each tissue. We found that cardiac muscle has the highest rate of protein turnover, followed by slow-twitch skeletal muscle and then fast-twitch skeletal muscle, and that these different rates of protein turnover are driven by different levels of muscle use, rather than myosin isoform composition. We also identified protein age heterogeneity at the myofiber and sarcomere levels. These findings uncover fundamental principles of muscle protein maintenance and have broad implications for understanding cellular aging, muscle disease, and the design of therapeutic strategies targeting muscle protein turnover.

Animals

Extreme Temperature and Incident Diabetes Risk Among Middle-Aged and Older Adults in China: A National Longitudinal Cohort Study.

BACKGROUND AND AIMS: The metabolic consequences of extreme temperature exposure in nondiabetic populations remain poorly understood. This study aimed to examine associations between heatwave and coldwave exposure and incident diabetes mellitus (DM) and impaired glucose tolerance (IGT) in middle-aged and older Chinese adults. METHODS: A total of 1803 China Health and Retirement Longitudinal Study participants aged &#x2265;45 years with normoglycemia at baseline were followed from Wave 1 (2011) to Wave 3 (2015). Eighteen extreme-temperature indicators were derived from city-level fifth-generation European Centre for Medium-Range Weather Forecasts atmospheric reanalysis data. Outcomes were classified according to American Diabetes Association criteria. Generalized linear mixed-effects models (GLMMs) were pooled across five imputed datasets, with Bonferroni correction for multiple comparisons (&#x3b1; = 0.0028) and sensitivity analysis adjusting for individual follow-up duration. RESULTS: All nine heatwave indicators showed odds ratios (ORs) < 1.0 for DM and IGT. HT9 (&#x2265;97.5th percentile, &#x2265;4 consecutive days) was the sole Bonferroni-significant result: OR = 0.845 (95% confidence interval [CI]: 0.802-0.890). Coldwave indicators showed no consistent associations. Age significantly modified the HT9 effect (P-interaction = 0.004): adults aged 65-84 showed a stronger inverse association (OR = 0.616) than those aged < 65 (OR = 0.921). CONCLUSION: Prolonged heatwave exposure was consistently associated with reduced diabetes risk, with pronounced age heterogeneity. Replication in larger prospective studies is warranted.

Humans

Age-associated epigenomic heterogeneity in papillary tumors of the pineal region: a multicenter YoungNOA investigation.

BACKGROUND: Papillary tumors of the pineal region (PTPR) are rare CNS neoplasms with adult and pediatric presentations, but whether age defines distinct molecular biology is unclear. METHODS: We assembled a multicenter retrospective cohort of 86 histologically confirmed PTPR with genome-wide DNA methylation data, comprising 62 adult and 24 pediatric tumors. Molecular subgroup, array platform, sex, and tumor purity were incorporated into multivariable models. Analyses included DNA methylation class assignment, differential methylation, copy-number variation (CNV), epigenetic mitotic-clock scores, methylation-based tumor microenvironment deconvolution, and descriptive survival evaluation. RESULTS: Adult and pediatric tumors mapped within the established PTPR-A and PTPR-B methylation framework rather than forming age-defined methylation classes. Pediatric tumors were enriched for PTPR-B (22 of 24 tumors [91.7%]) compared with adult tumors (39 of 62 [62.9%]). After adjustment for methylation-based subgroup as well as technical and biological covariates, 2,923 CpG probes were associated with age at a false discovery rate (FDR) threshold below 0.05, and 530 also met the prespecified effect-size threshold. Global methylation summaries were similar between age groups. CNV patterns were dominated by molecular subgroup; adjusted genomic CNV load was not independently associated with pediatric age. In contrast, epiTOC2 intrinsic rate score and the methylation signature represented by the first principal component (PC1) showed age-associated effects independent of molecular subgroup. Methylation-based deconvolution suggested a limited microenvironmental signal, with neutrophil fraction showing the most consistent adjusted association. CONCLUSIONS: Adult and pediatric PTPR share the established PTPR-A/PTPR-B framework. Pediatric tumors, particularly within PTPR-B, showed age-associated DNA methylation differences and higher epigenetic mitotic-clock (epiTOC2) scores in this retrospective cohort. These tissue-level associations do not establish clinical risk or treatment implications and require prospective clinical annotation and orthogonal validation.

Humans

Decoding age-stratified clinical and molecular heterogeneity in male breast cancer through multiomic profiling.

OBJECTIVE: Age-associated molecular heterogeneity is well described in female breast cancer but remains insufficiently characterized in male breast cancer (MBC). We profiled age-stratified clinical and molecular differences between younger (&#x2264;55 years) male breast cancer (YMBC) and older (>55 years) male breast cancer (OMBC). METHODS: We retrospectively analyzed 347 patients with MBC diagnosed at Fudan University Shanghai Cancer Center by integrating clinicopathological data, RNA sequencing, and whole-exome sequencing (WES). Survival, differential expression, and mutational signature analyses were performed. Tumor microenvironment features were inferred using xCell and ESTIMATE, and weighted gene co-expression network analysis (WGCNA) was conducted to identify age-associated co-expression modules. Candidate therapeutics were prioritized using the Genomics of Drug Sensitivity in Cancer (GDSC) resource and evaluated using patient-derived organoids (PDOs). RESULTS: Compared with OMBC, YMBC more frequently had human epidermal growth factor receptor 2 (HER2)-positive status (14.91% vs. 4.02%) and triple-negative tumors (4.92% vs. 1.78%), and had worse 5-year recurrence-free survival (hazard ratio=2.19, P=0.018). Transcriptomic analyses indicated enrichment of neural-related programs and reduced immune-related signaling in YMBC, and xCell/ESTIMATE supported lower immune infiltration. Consistently, WGCNA identified age-associated modules linking neural-related programs with reduced immune infiltration. Immunohistochemistry supported increased perineural invasion and lower CD8+ T cell infiltration in YMBC. GDSC-guided prioritization with PDO testing nominated sepantronium bromide (YM155) as a candidate vulnerability in YMBC. WES showed a higher NBPF10 mutation frequency in YMBC (54.5% vs. 14.3%, P<0.05). CONCLUSIONS: Integrated multi-omics profiling revealed age-stratified clinical and molecular heterogeneity in MBC. YMBC patients demonstrated inferior recurrence-free survival, neural signaling enrichment, an immune-cold microenvironment, and enriched NBPF10 mutations. These findings support age as a meaningful stratification variable in MBC risk assessment and treatment planning, and highlight the need for caution when considering treatment de-escalation in younger patients, while nominating YM155 as a candidate agent for prospective evaluation.

Male breast cancer

Age and early life adversity shape heterogeneity of the epigenome across tissues in macaques.

Age and early life adversity (ELA) are key determinants of health, but whether they affect similar physiological mechanisms across tissues is unknown. We generated DNA methylation (DNAm) profiles across 14 tissues in 237 semi-free-ranging rhesus macaques with naturally occurring ELA. Age-associated DNAm was predominantly tissue dependent, yet tissue-specific epigenetic clocks showed that epigenetic aging was relatively consistent within individuals. ELA effects were adversity dependent, but each ELA exerted coordinated effects across tissues. Although ELA targeted many of the same loci as age, the directions of effects differed, which indicates that ELA does not uniformly increase epigenetic age. Instead, ELA leaves a coordinated, cross-tissue epigenetic signature that is distinct from-yet intertwined with-age-related differences, which advances our understanding of how early environments sculpt the molecular foundations of aging and disease.

Animals

Age-dependent variations of antibody avidity.

Age-dependent variations of antibody avidity were studied in the C3HeB/FeJ mouse. Spleen cells from donors of different ages (10--720 days) were transferred and stimulated with TNP-HRBC in lethally irradiated syngenic recipients. The anti-TNP antibody response of the donor cells was estimated from the number of direct PFC per recipient spleen by the Jerne technique with TNP-SRBC. Avidity of the antibodies secreted by PFC was evaluated from the amount of added TNP-BSA that inhibited 50% of the anti-TNP PFC. Under these experimental conditions allowing the exclusion of any influence of the donor milieu during the immune response, age-dependent variations of the antibody response and avidity could be attributed to changes in the donor spleen cell population. Avidity was found to increase with the response and to vary parabolically with age. After appropriate correction of the number of PFC to make it independent from age, avidity values were fitted by a multiple curvilinear regression in which the independent variables playing a significant role were the corrected number of PFC in its linear term and the age in its linear and quadratic terms. From comparison of the standard coefficients of this regression, the observed variations of avidity could be attributed in part (82%) to the response and in part (18%) to the age. For any value of response, avidity increased 15-fold from day 10 to reach a maximum at day 110 and then declined 5-fold at the age of 720 days. Heterogeneity of avidity also changed parabolically with age as high avidity classes were present in adulthood and absent at 10 and 720 days.

Aging

Immunological studies of aging. II. Loss of IgG and high avidity plaque-forming cells and increased suppressor cell activity in aging mice.

The magnitude and heterogeneity of the immune response to dinitrophenylated bovine gamma globulin was measured in aged and young mice at a cellular level using an inhibition of plaque-forming cell assay. The primary and secondary responses of 24-mo-old mice were markedly depressed in magnitude and restricted in avidity for the DNP determinant when compared to 2-mo-old animals. Bacterial lipopolysaccharide given at the time of immunization increased the restriction in heterogeneity seen in 12- and 24-mo-old mice. Indirect PFCs were more severely depressed than direct PFCs in 24-mo-old mice. Syngeneic, lethally irradiated, 2-mo-old mice reconstituted with aged spleen cells exhibit the depressed and restricted response to DNP-BGG seen in old mice. When 10(8) young thymus cells were given together with old spleen cells the heterogeneity of the response was increased. When 2-mo- and 24-mo-old spleen cells were transferred together into young recipients the magnitude of the response to the young spleen cells markedly reduced. Thus, there appears to be a loss of thymic-helper cells and an increase in suppressor activity in aged animals.

Aging

Restriction of immunoglobulin heterogeneity, autoimmunity and serum protein levels in aged people.

Ninety-one sera of persons above 80 years of age were screened for autoantibody activity against lipoproteins (anti-LDL 7, anti-HDL 6 positive), for rheumatoid factor activity (Latex 14, Waaler-Rose 7 positive) and for antinuclear factors (11 positive). Among the sera with autoantibody activity 29 percent showed deviations of the normal kappa/lambda ratio of immunoglobulins, as opposed to 22 percent of the sera without detected autoantibody activity. In 3 percent of the sera an M component was detected. Determination of the alpha1-acid glycoprotein, alpha1-antitrypsin, haptoglobin, haemopexin, complement component C3c and C4, IgG, IgA and IgM levels showed significant increases in alpha-, and beta-globulins as well as in IgG and IgA in sera of the aged persons as compared to a normal population between 20 and 60 years old. No significant difference was noted between the gamma-globulin concentration in sera of aged persons with or without autoantibody activity. The evaluation of the relationship between serum protein levels and alterations of the kappa/lambda ratio indicated that the alpha- and the beta-globulins were significantly raised in sera with altered kappa/lambda ratios, whereas, with the exception of M component containing sera the gamma-globulin levels seemed not significantly affected by changes in this ratio.

Aged

Mechanisms of Hematopoietic Stem Cell Aging and Emerging Rejuvenation Strategies.

Hematopoietic stem cell (HSCs) aging is a complex biological process driven by both cell-intrinsic alterations and extrinsic cues from the bone marrow niche. Understanding these mechanisms is critical for developing therapies against aging-related hematopoietic disorders. This review synthesizes recent advances in the molecular mechanisms underlying HSCs aging, including microenvironmental aging, genomic instability, epigenetic dysregulation, mitochondrial dysfunction, and aberrant nuclear mechanotransduction. We summarize that the functional decline of HSCs during aging drives a compensatory expansion of the phenotypically defined stem cell pool, leading to an aberrant increase in cell number. We also highlight aging-associated HSCs heterogeneity, including CD150high and P-selectin-positive subsets that enrich for myeloid-biased or functionally compromised HSCs states while emphasizing that surface phenotype alone may not fully indicate functional rejuvenation. Finally, we discuss emerging rejuvenation strategies-including targeting myeloid-biased HSCs, modulating inflammatory pathways, and implementing epigenetic or metabolic interventions-supported by cutting-edge technologies such as single-cell multi-omics, gene editing, and computational modeling. These approaches hold promise for counteracting age-related hematopoietic decline and restoring immune competence.

Humans

The use of multiple thresholds and segregation analysis in analyzing the phenotypic heterogeneity of multifactorial traits.

(1) Three models based on multifactorial inheritance are introduced to account for phenotypic heterogeneities. These models are used to determine whether subforms of a triat are: (a) different degrees of the same process, (b) non-familial environmental variants of the same process, and (c) independently transmitted processes. (2) The parameters of each model consist of two population prevalences and either one, two, or three correlation coefficients which reflect the three hypotheses given above. The models are formulated so that a likelihood ratio test may be performed to discriminate between them. (3) The following types of analyses are described: (a) analysis of prevalence data with separate population prevalence estimates, (b) analysis of prevalence data with the proband a parent with specified spouse, (c) analysis of prevalence data with the proband an offspring with specified parents, and (d) the full segregation distribution of families using Complex Segregation Analysis. (4) When compared with the Analysis of Prevalences, Complex Segregation Analysis has the following advantages: (a) the number of degrees of freedom for parameter estimates is greater and separate estimates of the population prevalences are not necessary, (b) standard errors of the parameters are smaller, and (c) the power to discriminate models is increased. (5) Phenotypic heterogeneities such as age of onset, severity, and sex effect can be more completely understood by the methods of analyses described above. The nosology of familial disorders can also be clarified, and environments relevant to the transmission of the trait can be detected. This approach is particularly suitable for the analysis for behavioural traits since it does not require the assumption that environmental effects common to relatives be ignored. (6) Finally, our experience indicates that incorporating both prevalence and pedigree data into a single analysis decreases the time required to perform the analysis.

Environment

Metabolomic ageing across mental and behavioural disorders.

BACKGROUND: Individuals with mental disorders face excess morbidity and premature mortality. Accelerated ageing has been proposed as a contributing mechanism but population-scale evidence across diverse diagnoses is limited. OBJECTIVE: To examine whether metabolomic ageing differs across mental disorders and whether associations vary by sex, age group and genetic liability. METHODS: Using plasma metabolomic profiles from UK Biobank participants, we applied a metabolomic ageing clock (MileAge) to estimate disorder-specific differences between metabolite-predicted and chronological age. Mental disorders were ascertained from health records and self-reported physician diagnoses. We analysed nine diagnostic groups and 45 individual disorders and assessed sex and age group differences and associations with polygenic scores. FINDINGS: Among 225&#x2009;212 participants (54% female; mean age 56.97), 38&#x2009;524 had a diagnosis preceding baseline. Substance use, psychotic, affective and neurotic disorders were associated with a metabolite-predicted age older than chronological age, largest for psychosis (&#x3b2;=0.556, 95% CI 0.250 to 0.861, p<0.001). Obsessive-compulsive and eating disorders were associated with a metabolite-predicted age younger than chronological age. Several associations were stronger in males and in individuals aged <65 years. Higher genetic liability to depression, autism and attention-deficit/hyperactivity disorder predicted an older metabolomic age (&#x3b2; range=0.020&#x2009;to 0.047), whereas polygenic scores for psychosis and tobacco use disorder predicted a younger metabolomic age (&#x3b2; range=-0.023&#x2009;to -0.040). For obsessive-compulsive disorder and anorexia nervosa, clinical and genetic associations indicated younger metabolomic ageing. CONCLUSIONS: Metabolomic ageing in mental disorders is heterogeneous. While many disorders are associated with an older biological age, some are linked to a younger biological age. Divergence between genetic liability and clinical phenotypes suggests that non-genetic factors shape biological ageing differences. CLINICAL IMPLICATIONS: Biological age should not be assumed to uniformly exceed chronological age across mental disorders. Sex and age-specific approaches could improve understanding of biological ageing processes in psychiatry.

Humans

Hemopoietic stem cell heterogeneity: use of cell cycle-specific drugs to look for age-associated alterations.

Hemopoietic tissue is vulnerable to perturbations, and data show that it is an appropriate tissue in which to look for age-associated alterations. This tissue has a high regenerative capacity, is composed of a heterogeneous population of stem cells that are capable of self renewal or differentiation, or both, and is sustained by a pool of resting cells. The heterogeneity of bone marrow has made characterization of the cellular elements difficult. Techniques commonly used to identify and quantify the various maturation levels of hemopoietic stem cells and the limitations of these techniques are discussed. Most techniques used to assay age-associated changes in bone marrow have not differentiated between specific cellular alterations or shifts in the distribution of the cellular elements. In particular, it has been difficult to determine the stability of the non-dividing stem cell because of the low incidence of this cell (6 per 1000) and the lack of a specific assay for this important cell type. The use of cell cycle-specific drugs has provided quantitative information on specific subpopulations of hemopoietic stem cells and seems to be the most promising approach towards determining qualitative and quantitative differences in the hemopoietic stem cells of young and old individuals.

Aging

The effect of aging on carbohydrate metabolism: a review of the English literature and a practical approach to the diagnosis of diabetes mellitus in the elderly.

There seems little doubt that the disposal of a glucose load is progressively impaired during aging. The mechanism(s) for this alteration remains unclear. Five possibilities have been raised: (1) poor diet, (2) physical inactivity, (3) decreased lean body mass in which to store the carbohydrate load, (4) decreased insulin secretion, and (5) insulin antagonism. Although poor diet and physical inactivity may contribute to some of the abnormal glucose tolerance tests of the older population, these two factors do not provide a full explanation. Diminished lean body mass may play some role but there is almost certainly an additional effect due to aging. A few papers have suggested that glucose-induced insulin secretion may be impaired as the population ages, but the bulk of studies in this area conclude that normal or increased amounts of insulin are released by the pancreatic beta-cell during aging. If abnormalities of insulin secretion exist, either in degree or timing, they are subtle and would not seem sufficient to account for the great number of older subjects who manifest impaired glucose tolerance. The evidence for insulin antagonism seems the strongest but the data are certainly not conclusive. In actuality, the aging effect on carbohydrate metabolism may be heterogeneous in nature. Either some or all of these five factors may contribute to the aging effect to varying degrees in individual subjects. Alternatively, the glucose intolerance of aging may represent a heterogeneous group of disorders. In any event, until better methods to identify possible subgroups of these subjects and/or a marker for diabetes mellitus independent of glucose concentration become available, this problem will remain difficult to resolve. Based on the currently available data, it seems prudent to diagnose diabetes mellitus only if fasting hyperglycemia is present.

Aged