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PubMed2026

GT-Mamba: a Topology-Aware Graph-State space model for robust and interpretable epigenetic age prediction.

MOTIVATION: Current epigenetic clocks face a trade-off between predictive accuracy and biological interpretability, often relying on dataset-specific correction to generalize across cohorts. We propose GT-Mamba, a novel architecture that integrates a Structure-Aware Graph Transformer with the Mamba state space model. This design captures CpG topological correlations and genome-wide long-range dependencies. RESULTS: GT-Mamba demonstrates strong out-of-the-box robustness across heterogeneous independent validation cohorts, achieving a weighted average MAE of 4.43 years. Notably, it effectively generalizes to EPIC 850k arrays despite partial feature missingness, and maintains consistent performance across homologous age distribution shifts (MAE 2.94 years in a young cohort). Ablation studies confirm that graph topology contributes to improved robustness against noise. Mechanistic analysis suggests that the model captures methylation patterns associated with both developmental and functional processes. AVAILABILITY: Source code and pre-trained models are freely available at https://github.com/NENUBioCompute/GT-Mamba and archived on Zenodo (DOI: 10.5281/zenodo.19703155).

Epigenesis, Genetic↗
PubMedDate not supplied

Ultradian cardiac rhthms in surgical intensive care unit patients.

Several reports have suggested that heart rate may be regulated by an ultradian biological rhythm with a period of about 90--100 min. Blood pressure and heart rate were collected from 10 Surgical Intensive Care patients at 5-min intervals and analyzed by computer. No 90-min rhthms were found, indicating this rhythm has no significant influence on heart rate or blood pressure in postsurgical patients.

Adult↗
PubMed2026

Characterization of DNA methylation in PBMCs and donor-matched iPSCs shows age-related methylation is reset during stem cell reprogramming.

DNA methylation is an important epigenetic mechanism that helps define and maintain cellular functions. It is influenced by many factors, including environmental exposures, genotype, cell type, sex, and aging. Since age is the primary risk factor for developing neurodegenerative diseases, it is important to determine if age-related DNA methylation is retained when cells are reprogrammed to an induced Pluripotent Stem Cell (iPSC) state. Here, we selected peripheral blood mononuclear cells (PBMCs; n = 99) from a cohort of diverse and healthy individuals enrolled in the Genetic and Epigenetic Signatures of Translational Aging Laboratory Testing (GESTALT) study to reprogram to iPSCs. After reprogramming, the resulting iPSCs were evaluated for DNA methylation signatures to determine if they reflect the confounding factors of aging and environmental effects. Data from genome-wide DNA methylation arrays in both cell types showed that age-related methylation measured by epigenetic clocks is largely reset to an early methylation age after reprogramming of PBMCs to iPSCs. We further examined the epigenetic age of each cell type using an Epigenome-wide Association Study (EWAS) and identified a set of methylation Quantitative Trait Loci in each cell type. Our results show that age-related DNA methylation is largely reset in iPSCs, and each cell type has a unique set of methylation sites that are modified by population-level genetic variation.

DNA Methylation↗
PubMed1979

Progress in cytogerontology.

The finite in vitro lifetime of cultured normal cells is interpreted to be aging at the cellular level. In addition to the inverse relationship between donor age and population doubling potential (PDP), a number of biochemical and physiological increments and decrements occur prior to the cessation of cell division. The reconstruction of replicating normal human cells from the nuclei of "young" cells and the cytoplasm of "old" cells (and the reverse) suggests that the nucleus governs PDP. Several morphological changes were found to occur in late phase III cells held for up to one year in culture. Autoradiography studies show that (1) a cell population may be composed of several subpopulations, each of which is at a different stage in its life history and (2) lipid synthesis is affected much less as cells age than is DNA, RNA and protein synthesis. Changes occurring in the genetic program of individual cells seem to be the most tenable hypothesis to explain fundamental causes of aging.

Aging↗
PubMed2026

Sex-specific differences in liver DNA methylation patterns and epigenetic aging in mice.

Biological sex has been shown to influence aging outcomes, contributing to distinct trajectories in disease susceptibility and lifespan. DNA methylation patterns provide a quantitative measure of biological aging. This study investigated whether aged male and female mice display distinct liver DNA methylation patterns and differences in epigenetic aging. Liver samples were collected from 17 aged c57BL/6 mice (6 males, 11 females). Genomic DNA was extracted and bisulfite-converted before targeted enrichment of 2,045 murine age-associated CpG loci. Biological age (DNAge) was estimated using a previously developed DNA methylation-based predictor generated through elastic net regression. The difference (ΔDNAge) between DNAge and chronological age was computed. Sex-specific differences were assessed by comparing site-specific methylation ratios, ΔDNAge values, and through principal component analysis (PCA) and multiple linear regression. Twelve CpG sites across six genes (Fam84b, Zswim6, Hsf4, Mn1, Qprt, and Rapgefl1) showed significant sex-associated differences in methylation. Fam84b demonstrated the largest and most consistent sex-associated effect, with all three associated CpG sites showing higher methylation in males (regression coefficients: -0.204, -0.281, and -0.294). Zswim6 exhibited consistent lower methylation ratios in females, whereas the other genes showed higher methylation in females. There were no sex differences in biological age or ΔDNAge (P = 0.596). Although the epigenetic clock did not reveal differences between sexes in aging, aged mice did exhibit sex-specific liver methylation patterns different from those reported in younger mice, suggesting that sex-dependent epigenetic changes may emerge later in life and may reflect sexual dimorphism in liver function with age.NEW & NOTEWORTHY Males and females are known to age differently and develop certain diseases at different rates. Here, we examined the livers of aged male and female mice to see if they show different DNA methylation patterns. We found that aged male and female mice had distinct DNA methylation patterns at specific genes. Interestingly, most of these methylation differences were not present in younger mice, suggesting that sex differences in the genome may change with age.

Animals↗
PubMed2025

Genome-wide methylation biomarkers and biological aging in patients with bipolar disorder characterized for lithium response.

BACKGROUND: Epigenetic mechanisms might play a role in modulating susceptibility to bipolar disorder (BD) and response to lithium, the mainstay treatment for BD. Additionally, individuals with BD experience accelerated biological aging. METHODS: We compared blood DNA methylation profiles measured with EPIC v.2.0 arrays between patients with BD (33 lithium responders and 31 nonresponders) and nonpsychiatric controls (n = 32), as well as based on long-term lithium response. In addition, we compared cellular aging between these groups using epigenetic age, pace of aging, and, for the first time, transcriptional age acceleration based on bulk RNA sequencing in 93 patients and 56 controls. RESULTS: We identified 191 differentially methylated positions (DMPs) and 8 differentially methylated regions between patients with BD and controls, located in genes enriched for "Postsynaptic Density" (odds ratio = 6.81, p = 0.001). No DMP was significantly associated with lithium response after multiple testing correction. Patients showed a significantly higher biological age acceleration than controls based on two epigenetic clocks (GrimAge, Mann-Whitney U = 551, p = 0.0009; GrimAge2: U = 477, p = 9.0E-05) and pace of aging (DunedinPACE, t = 3.01, p = 0.003), but not on transcriptional age. While we observed no significant difference in epigenetic aging based on lithium response, lithium responders showed lower epigenetic acceleration using all clocks, with a trend observed using the PhenoAge clock (t = 1.97, p = 0.053). CONCLUSIONS: Our findings point to methylation patterns characterizing BD and support the hypothesis of accelerated cellular aging in BD.

Humans↗
PubMed1976

Characteristics of a neural clock regulating perception and psychomotor performance in man.

A biological clock regulating some psychomotor aspects of perception has been adduced from the results of the repetitive administration of a maximal speed tapping test of 15 sec per hand per min for a total of 20 min. 412 longitudinal timed tests from 8 healthy control subjects, 4 physically healthy and 6 brain damaged psychiatric patients formed the basis for the investigation of the properties of this clock. It was found that this perceptual clock is endogenous, self-sustaining and innate. Its free-running oscillations are independent of psychic state, emotions and affect. They are, however, dependent upon the subject's neural integrity and their phase may be influenced by an orientating reflex. Timing is precise but the preceding phase may influence a succeeding one. Despite the muscular activity of the task the clock is relatively independent of body temperature. It is also immune to most psychoactive drugs.

Adult↗
PubMed2026

Age at menopause and subjective cognitive symptoms predict digital cognitive outcomes at the gynecological Well-Woman visit.

INTRODUCTION: Women are at increased risk for Alzheimer's Disease (AD). Growing evidence suggests that the menopausal transition may represent a vulnerable window for development of AD-related pathology. Yet, women are diagnosed with AD later than men. Conducting routine cognitive screenings and integrating information about both cognitive symptoms and age at menopause may help address sex-based disparities in detection and prevention. This study investigated whether subjective cognitive symptoms, in combination with age at menopause, were associated with performance on a digital cognitive task in postmenopausal women. METHODS: 183 postmenopausal women (mean age&#x2009;=&#x2009;63.8, range&#x2009;=&#x2009;45-85) were recruited after their Well-Woman visit. Participants completed the Screener for Cognitive Problems in Everyday Life (SCoPE) to assess subjective cognitive symptoms, followed by a sensitive measure of objective cognition: the Linus Health Digital Clock and Recall (DCR&#x2122;). Information was also collected on age at menopause. We examined associations of subjective cognitive symptoms and age at menopause with digital cognitive performance, adjusting for age, education and depression. Model fit was evaluated using adjusted R2, AIC, and BIC. RESULTS: 48.1% of women reported one or more cognitive symptoms on the SCoPE. On objective testing, 73.2% scored in the normal range, 20.8% in the borderline range, and 6.0% in the impaired range. SCoPE total score was negatively associated with objective cognitive performance in adjusted models (B&#x2009;=&#x2009;-.12, p&#x2009;=&#x2009;.03). Age at menopause showed a significant quadratic association with cognitive performance (B&#x2009;=&#x2009;-0.006, p<.001). SCoPE total was not associated with DCR subtests, while age at menopause predicted both Delayed Recall and Clock Drawing. CONCLUSION: Subjective cognitive symptoms and age at menopause were associated with lower performance on a sensitive, objective cognitive test. Findings support routine cognitive screening and suggest that subjective cognitive symptoms as well as age at menopause are associated with cognitive function.

Humans↗
PubMed2026

Differences between mitotically old and young endometrial tumors.

Human tumors likely differ in their mitotic ages, reflecting how many divisions elapse between the final tumor progenitor cell and surgical removal. We used a rapidly fluctuating CpG (fCpG) methylation clock to infer relative endometrial adenocarcinomas (EAC) mitotic ages. Experimentally, young tumors initiated from single cells show low-diversity, high-variance fCpG distributions with trimodal peaks near 0%, 50%, and 100%, reflecting inherited progenitor methylation states. fCpG methylation becomes polymorphic with divisions, and older tumors exhibit higher diversity, lower variance, and unimodal distributions centered around 50%. Mitotic ages varied across EAC samples. Synchronous hyperplasia and invasive regions generally shared similar ages, and primary-metastatic EAC pairs showed both synchronous and stepwise progression. The Cancer Genome Atlas (TCGA) EACs also showed variable mitotic ages: younger tumors were enriched for proliferation pathways, whereas older tumors showed more immune infiltration, immune-pathway activation, and evidence of T-cell exhaustion. These results show that human tumors can be ranked by mitotic age and suggest that the growth of older cancers is restrained by immune surveillance. &#xa9; 2026 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Humans↗
PubMed2026

Methylation profiling of normal tissue adjacent to breast tumors reveals two distinct groups with divergent tumor microenvironment features.

We previously identified diverse genetic evolutionary patterns in whole-genome sequencing of paired normal tissue adjacent to tumor (NAT) and tumor tissues from Hong Kong breast cancer (HKBC) patients. Here, we investigated whether DNA methylation (DNAm) contributes to NAT heterogeneity and shapes the tumor microenvironment (TME). Genome-wide DNAm profiling was performed on paired NAT and tumor tissues from 188 HKBC patients using the Infinium 850&#x2009;K array. RNA-seq data were available for 76 NATs and 177 tumors. Cellular composition was inferred using MethylCIBERSORT, CIBERSORTx, and EpiDISH, and histopathologic features were assessed on 115 H&E-stained sections. Unsupervised clustering identified two distinct NAT subtypes with divergent TME characteristics. Cluster 1 (N&#x2009;=&#x2009;139) showed higher epithelial and fibroblast content and enrichment of estrogen response pathways. Cluster 2 (N&#x2009;=&#x2009;49) exhibited an immune-metabolic phenotype characterized by increased fat and immune cells, stromal disruption, inflammatory pathway activation, and greater macrophage infiltration. Cluster 2 patients also demonstrated significantly younger epigenetic age estimated using multiple epigenetic clocks. These DNAm-defined NAT subtypes and associated TME features were validated in 97 NAT samples from TCGA breast cancer patients. Overall, our findings identify DNAm-driven NAT heterogeneity with distinct TME landscapes, providing new insights into field cancerization and tumor evolution in breast cancer.

Journal Article↗
PubMed1979

Prolactin. I. Mechanisms of control, peripheral actions and modification by drugs.

The role of neurotransmitters in the release of prolactin (PRL) is reviewed. Special attention is paid to dopamine (DA) as the possible prolactin-inhibiting factor (PIF). Among other agents, estrogens alone can act directly on the pituitary galactotropes without involving hypothalamic factors. Peripherally, in addition to its stimulatory action on mammary tissue, PRL exerts a permissive role on ovarian steroidogenesis. A possible physiological action of this hormone on the regulation of adrenal function remains uncertain. The secretory rhythms of PRL are described and the mechanisms involved are discussed. A number of drugs can modify the secreting pattern of PRL mainly by acting on the dopaminergic control mechanisms. The usefulness of such agents in the clinical evaluation of galactotrope cell function is reviewed.

Adolescent↗
PubMed1978

Evidence for existence of a yearly clock in surgically and self-blinded chipmunks.

By use of simplified technique and constant environmental conditions, I have demonstrated the existence in the chipmunk of a yearly clock. In a blinded chipmunk the clock manifested itself by remarkably consistent changes in running activity, food and water intake, and body weight over 6 1/2 yr. Studies on freshly trapped chipmunks kept in the same laboratory environment but with alternating light and darkness (12 hr each), showed that, when their eyes were covered for much of the light period, they reduced their exposure to light to preserve the activity of the yearly clock. Laboratory-adapted chipmunks that do not shield their eyes from light do not show the clock. The yearly clock has all the characteristics of the 24-hr clock, including sharply defined active and inactive phases, and must likewise play an important part in the animal's survival. Light would appear to be the chief or only cue for the clock. The period lengths did not change with age during the 6 1/2 yr.

Animals↗
PubMed2026

Assessing the influence of different alignment tools on the accuracy of a forensic epigenetic clock.

MOTIVATION: DNA methylation (DNAm) has long been a commonly investigated biomarker in biomedical research. The current gold standard for DNAm detection is bisulfite sequencing which requires dedicated alignment tools that can handle reduced sequence complexity. One commonly used application of DNAm are epigenetic clock measurements. These clocks have been adapted by many fields for their specific needs, including forensic genetics. Here, epigenetic clocks were designed to help estimate the chronological age of a biological stain donor for investigative purposes. RESULTS: In this study, data generated with a well-established forensic epigenetic clock is aligned with four different bisulfite-specific alignment tools: "Bwa-meth," "Abismal," "Bismark," and "BS-Seeker2." For each tool, we tested up to six different settings, altering parameters such as the maximum number of mismatches or the score function setting. The goal was to investigate whether the final predicted ages differed considerably between the tested alignment tools and settings. Quality controls such as read depth, precision, recall, F1 score, and alignment run time were also assessed. To allow other researchers to easily perform such methylation comparison analyses on their own data, a Shiny app called "MethylAge Explorer" was developed within this study. None of the tested settings for the three alignment tools "Abismal," "Bismark," and "BS-Seeker2" outperformed the originally used alignment tool "Bwa-meth" in terms of age prediction accuracy. However, differences in final age predictions were observed between the different alignment tools. Therefore, it is necessary to be aware of which alignment tool to use for particular epigenetic clocks. AVAILABILITY AND IMPLEMENTATION: The data underlying this article and the code for the shiny app are available on GitHub (https://github.com/charlsut/methylage_explorer).

DNA Methylation↗