Stress and telomere shortening: Insights from cellular mechanisms

Aging and Lifestyle Modifications for Preventing Aging-Related Diseases

The pathogenesis of various chronic diseases is closely associated with aging. Aging of the cardiovascular system promotes the development of severe cardiovascular diseases with high mortality, including atherosclerosis, coronary heart disease, and myocardial infarction. Similarly, aging of the nervous system promotes the development of neurodegenerative diseases, such as Alzheimer's disease, which seriously impairs cognitive function. Aging of the musculoskeletal system is characterized by decreased function and mobility. The molecular basis of organ aging is cellular senescence, which involves multiple cellular and molecular mechanisms, such as impaired autophagy, metabolic imbalance, oxidative stress, and persistent inflammation. Given the ongoing demographic shift toward an aging society, strategies to delay or reduce the effects of aging have gained significance. Lifestyle modifications, such as exercise and calorie restriction, are now recognized for their anti-aging effects, their capacity to reduce modification, their potential to prolong lifespan, and their capacity to lower the risk of cardiovascular disease. This review elucidates the molecular mechanisms and application significance of various anti-aging approaches at the molecular level, based on research progress in aging. It aims to provide a reference for the prevention and treatment of age-related diseases in progressively aging societies.

Aging and autophagic phenotypic changes in bone marrow mesenchymal stem cells in glucocorticoid-induced osteonecrosis

BACKGROUND

Glucocorticoid (GC) overuse is the main cause of osteonecrosis of the femoral head (ONFH). The dysfunction of bone marrow mesenchymal stem cells (BMSCs) plays an important role in ONFH pathogenesis. Physiological concentrations of GCs can induce the osteogenic differentiation of BMSCs; however, intervention with high concentrations of GC may lead to changes in aging and autophagy in certain cell types.

METHODS

We generated an ONFH mouse model by injecting C57BL/6 J mice with MPS. BMSCs were harvested from the femora and tibiae of mice and were analyzed for osteogenesis, adipogenesis, senescence, and cell proliferation. In vitro, BMSCs were treated with different concentrations of GC for 48 h, followed by functional analyses to identify differentially expressed genes (DEGs) associated with ONFH. Additionally, various bioinformatics analyses were performed to identify differentially expressed genes in ONFH.

RESULTS

BMSCs from ONFH mice showed signs of aging, as indicated by increased SA-β-gal positive cells (4.4-fold) and upregulated p53 (2.6-fold) and p21 (2.0-fold) protein expression. It is also accompanied by changes in osteogenic/lipogenic differentiation ability. Bioinformatics analysis further verified these findings. High-dose GC stimulation significantly induced cellular senescence of BMSCs, as indicated by an increase in SA-β-gal positive cells (6.2-fold) and a decrease in autophagy levels. GC stimulation changes the differentiation fate of BMSCs.

CONCLUSIONS

Our results indicated that GC-induced ONFH was associated with changes in aging and autophagy in BMSCs. GC not only directly affected the osteogenic differentiation of BMSCs but also indirectly affected their differentiation fate through aging and autophagy changes.

Exploring the relationship between religiosity and telomere length in older individuals

OBJECTIVES

Although telomere length is an established marker of biological aging, the impact of religious beliefs on telomere length remains uncertain.

METHODS

This cross-sectional study investigated the relationship between religiosity and telomere length among senior Brazilians, aged 60 and older. The study examined the association between organizational, non-organizational, and intrinsic religiosity with telomere length, adjusting for sociodemographic, mental, physical health, and medication. Hierarchical linear regression models were used.

RESULTS

821 participants (62.2 % female, mean age 68.9 years, SD = 6.48) were studied. Female gender and younger age were linked to longer telomeres, but no significant associations were found between religious beliefs and telomere length in adjusted or unadjusted models.

CONCLUSIONS

This study found no evidence of an association between religiosity and telomere length among older Brazilian adults. While prior research highlights religiosity's positive health effects, its direct influence on telomere length remains unclear, warranting further exploration.

Protection of the genome and the central exome by peripheral non-coding DNA against DNA damage in health, ageing and age-related diseases

DNA in eukaryotic genomes is under constant assault from both exogenous and endogenous sources, leading to DNA damage, which is considered a major molecular driver of ageing. Fortunately, the genome and the central exome are safeguarded against these attacks by abundant peripheral non-coding DNA. Non-coding DNA codes for small non-coding RNAs that inactivate foreign nucleic acids in the cytoplasm and physically blocks these attacks in the nucleus. Damage to non-coding DNA produced during such blockage is removed in the form of extrachromosomal circular DNA (eccDNA) through nucleic pore complexes. Consequently, non-coding DNA serves as a line of defence for the exome against DNA damage. The total amount of non-coding DNA/heterochromatin declines with age, resulting in a decrease in both physical blockage and eccDNA exclusion, and thus an increase in the accumulation of DNA damage in the nucleus during ageing and in age-related diseases. Here, we summarize recent evidence supporting a protective role of non-coding DNA in healthy and pathological states and argue that DNA damage is the proximate cause of ageing and age-related genetic diseases. Strategies aimed at strengthening the protective role of non-coding DNA/heterochromatin could potentially offer better systematic protection for the dynamic genome and the exome against diverse assaults, reduce the burden of DNA damage to the exome, and thus slow ageing, counteract age-related genetic diseases and promote a healthier life for individuals.

Association Between Maternal Prepregnancy and Pregnancy Body Mass Index and Children's Telomere Length: A Systematic Review and Meta-analysis

CONTEXT

Telomeres maintain chromosome stability and mark cellular aging, and their shortening with age compromises genomic stability.

OBJECTIVE

The purpose of this study was to conduct a meta-analysis of existing evidence to evaluate the relationship between the maternal pregnancy body mass index (BMI) and children's telomere length (TL).

DATA SOURCE

Web of Science, Scopus, and PubMed databases were systematically searched from their inception to August 27, 2023, for pertinent observational studies.

DATA EXTRACTION

The random-effects meta-analysis was conducted on eligible studies that investigated the linear relationship between exposure and the outcomes of interest, utilizing the reported β-coefficient. Cochran's Q test and I2 statistics were used to assess heterogeneity.

DATA ANALYSIS

A significant association was observed between maternal pregnancy BMI and children's TL (32 studies, pooled effect size [ES]: -0.04; 95% CI: -0.06 to -0.01; I2 = 47.51%, P < .001) and maternal prepregnancy BMI and children's TL at birth (16 studies; pooled ES: -0.05; 95% CI: -0.08 to -0.02; I2 = 53.49%, P < .001).

CONCLUSION

The findings indicate an inverse association between maternal prepregnancy BMI and TL in infants, which is evident within the normal to obese BMI range. This underscores the significance of maternal weight status before pregnancy as a determinant of offspring TL.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42023466425.

Premature aging and metabolic diseases: the impact of telomere attrition

Driven by genetic and environmental factors, aging is a physiological process responsible for age-related degenerative changes in the body, cognitive decline, and impaired overall wellbeing. Notably, premature aging as well as the emergence of progeroid syndromes have posed concerns regarding chronic health conditions and comorbidities in the aging population. Accelerated telomere attrition is also implicated in metabolic dysfunction and the development of metabolic disorders. Impaired metabolic homeostasis arises secondary to age-related increases in the synthesis of free radicals, decreased oxidative capacity, impaired antioxidant defense, and disrupted energy metabolism. In particular, several cellular and molecular mechanisms of aging have been identified to decipher the influence of premature aging on metabolic diseases. These include defective DNA repair, telomere attrition, epigenetic alterations, and dysregulation of nutrient-sensing pathways. The role of telomere attrition premature aging in the pathogenesis of metabolic diseases has been largely attributed to pro-inflammatory states that promote telomere shortening, genetic mutations in the telomerase reverse transcriptase, epigenetic alteration, oxidative stress, and mitochondrial dysfunctions. Nonetheless, the therapeutic interventions focus on restoring the length of telomeres and may include treatment approaches to restore telomerase enzyme activity, promote alternative lengthening of telomeres, counter oxidative stress, and decrease the concentration of pro-inflammatory cytokines. Given the significance and robust potential of delaying telomere attrition in age-related metabolic diseases, this review aimed to explore the molecular and cellular mechanisms of aging underlying premature telomere attrition and metabolic diseases, assimilating evidence from both human and animal studies.

The relationship between telomere length and aging-related diseases

The intensifying global phenomenon of an aging population has spurred a heightened emphasis on studies on aging and disorders associated with aging. Cellular senescence and aging are known to be caused by telomere shortening. Telomere length (TL) has emerged as a biomarker under intense scrutiny, and its widespread use in investigations of diseases tied to advancing age. This review summarizes the current knowledge of the association between telomeres and aging-related diseases, explores the important contribution of dysfunctional telomeres to the development and progression of these diseases, and aims to provide valuable insights for the development of novel therapeutic strategies.

Stress and telomere length in leukocytes: Investigating the role of GABRA6 gene polymorphism and cortisol

Telomere length (TL) is considered a biomarker of aging, and short TL in leukocytes is related to age and stress-related health problems. Cumulative lifetime stress exposure has also been associated with shorter TL and age-related health problems, but the mechanisms are not well understood. We tested in 108 individuals whether shorter TL in leukocytes is observed in individuals with the GABRA6 TT genotype, which has been associated with dysregulation of hypothalamic-pituitary-adrenal axis activity (the main biological stress system) compared to the CC genotype. We also investigated if individuals carrying the TT genotype show higher stress-induced and diurnal cortisol secretion and if cortisol explains the interindividual variability in TL. The analysis pipeline of this study was pre-registered, and the results showed that GABRA6 TT carriers had shorter TL in CD8+CD28+ cells (Bonferroni corrected). In contrast to previous studies, no differences between groups in cortisol secretion were observed, and TL and cortisol did not show significant associations. This study shows, for the first time, shorter TL in CD8+CD28+ cells in TT carriers for GABRA6 compared to CC carriers, suggesting accelerated cellular aging. Although this difference could be linked to an increased susceptibility to stress in the TT carriers, this could not be attributed to the direct influence of cortisol, suggesting the involvement of other mechanisms.

Pleiotrophin Prevents H2O2-Induced Senescence of Dental Pulp Stem Cells

BACKGROUND

Dental pulp stem cells (DPSCs) are widely used in research on dental tissue regeneration and systemic disease treatment. However, the oxidative microenvironment often causes cellular senescence, leading to decreased function. Our previous study demonstrated that pleiotrophin (PTN), a secreted extracellular matrix-associated protein, could rescue the proliferative capacity and osteogenic differentiation of replicative senescent DPSCs.

OBJECTIVE

This study aimed to explore the influence and mechanism of PTN on dental pulp stem cells under H2O2-induced oxidative microenvironment.

MATERIALS AND METHODS

DPSCs isolated from human third molars were treated with 100 μm H2O2 for 4 h, mimicking the oxidative microenvironment. To investigate the influence of PTN on DPSC under H2O2-induced oxidative microenvironment, 50 pg/mL PTN was added in the culture medium for 48 h. RT-qPCR, western blotting, SA-β-gal staining, intracellular ROS production and immunofluorescence staining assays were used to analyse the cellular senescence, osteogenic differentiation capacity, oxidative stress conditions and possible mechanism.

RESULTS

H2O2 treatment increased the ratio of SA-β-gal-positive DPSCs and upregulated the senescence-related gene expression, including P53, P21 and P16. PTN pretreatment downregulated the ratio of SA-β-gal-positive DPSCs and the expression of these genes. Besides, PTN pretreatment partially reversed the H2O2-induced decreased osteogenic differentiation potential of DPSCs, total antioxidant capacity and Nrf2 and HO-1 mRNA expression in DPSCs. Western blotting and immunofluorescent staining results indicated that PTN pretreatment enhanced the Nrf2 nuclear translocation under oxidative stress conditions and observable higher fluorescence signals in the nucleus denoted PTN and Nrf2 colocalisation. Western blotting results showed that PTN reversed the decreased expression of p-AKT in the H2O2-induced oxidative environment. However, the PI3K inhibitor LY294002 blocked the upregulated levels of total Nrf2. Immunofluorescence staining displayed that LY294002 also inhibited the nuclear translocation of Nrf2 which was enhanced under PTN pretreatment.

CONCLUSIONS

This study demonstrated that PTN could prevent senescent damage induced by H2O2 on DPSCs, mainly by combining with Nrf2 and enhancing its nuclear translocation.

From bench to bedside: The critical need for standardized senescence detection

Cellular senescence, identified as a state of permanent cell cycle arrest, has become central to understanding aging and disease. Initially seen as a cellular aging mechanism, it is now recognized for its roles in development, tissu repair and tumour suppression. However, the accumulation of senescent cells with age contributes to chronic diseases such as diabetes, atherosclerosis and neurodegeneration. Recent efforts have focused on "senotherapeutics", including senolytics, which aim to eliminate senescent cells to mitigate age-related decline. Despite significant advances, senescence research faces critical challenges because of inconsistent detection methods. Common markers, such as p16INK4a and senescence-associated β-galactosidase, vary across tissues and contexts, complicating cross-study comparisons and clinical applications. A standardized multifaceted approach to senescence detection is essential, and should incorporate complementary methods, clear thresholds for senescence classification and considerations for cell type-specific variations. Such standardization would enhance reproducibility, streamline research and facilitate clinical translation, advancing therapeutic applications in aging and disease management.

Architecturally Mediated Allostasis and Neurosustainability: A Proposed Theoretical Framework for the Impact of the Built Environment on Neurocognitive Health

The global rise in mental health-related disorders represents a significant health and wellbeing challenge, imposing a substantial social and economic burden on individuals, communities, and healthcare systems. According to the World Health Organization, one in four people globally will be affected by mental or neurological disorders at some point in their lives, highlighting a significant global health concern that warrants carefully considered and innovative responses. While mental health challenges arise from complex, multifaceted factors, emerging research indicates that the built environment-the architecture of our homes, workplaces, and public spaces-may exert a critical but underappreciated influence on mental health outcomes. This paper outlines a novel theoretical framework for how visual stressors in the built environment might trigger neurophysiological stress responses via the HPA and SAM axes, potentially contributing over time to allostatic load. In this paper, it is proposed that chronic physiological strain can alter neuroplastic processes and neurogenesis in key brain regions-such as the hippocampus, prefrontal cortex (PFC), anterior cingulate cortex (ACC), and amygdala-thereby affecting cognitive health, emotional regulation, and overall mental wellbeing. Drawing on the principle of neurosustainability, this paper suggests that long-term exposure to stress-inducing environments may create feedback loops, particularly involving the amygdala, that have downstream effects on other brain areas and may be linked to adverse mental health outcomes such as depression. By presenting this framework, this paper aims to inspire further inquiry and applied experimental research into the intersection of neurophysiology, mental health, and the built environment, with a particular emphasis on rigorous testing and validation of the proposed mechanisms, that may then be translated into practical architectural design strategies for supporting health and wellbeing. In doing so, it is hoped that this work may contribute to a more holistic approach to improving mental health that integrates the creation of nurturing, resilient spaces into the broader public health agenda.

Exploring DNA methylation, telomere length, mitochondrial DNA, and immune function in patients with Long-COVID

BACKGROUND

Long-COVID is defined as the persistency or development of new symptoms 3 months after the initial SARS-CoV-2 infection, with these symptoms lasting for at least 2 months with no other explanation. Common persistent symptoms are fatigue, sleep disturbances, post-exertional malaise (PEM), pain, and cognitive problems. Long-COVID is estimated to be present in about 65 million people. We aimed to explore clinical and biological factors that might contribute to Long-COVID.

METHODS

Prospective longitudinal cohort study including patients infected with SARS-CoV-2 between March 2020 and March 2022. Patients were assessed between 4 and 12 months after infection at the COVID follow-up clinic at UZ Leuven. We performed a comprehensive clinical assessment (including questionnaires and the 6-min walking test) and biological measures (global DNA methylation, telomere length, mitochondrial DNA copy number, inflammatory cytokines, and serological markers such as C-reactive protein, D-dimer, troponin T).

RESULTS

Of the 358 participants, 328 were hospitalised, of which 130 had severe symptoms requiring intensive care admission; 30 patients were ambulatory referrals. Based on their clinical presentation, we could identify 6 main clusters. One-hundred and twenty-seven patients (35.4%) belonged to at least one cluster. The bigger cluster included PEM, fatigue, sleep disturbances, and pain (n = 57). Troponin T and telomere shortening were the two main markers predicting Long-COVID and PEM-fatigue symptoms.

CONCLUSIONS

Long-COVID is not just one entity. Different clinical presentations can be identified. Cardiac involvement (as measured by troponin T levels) and telomere shortening might be a relevant risk factor for developing PEM-fatigue symptoms and deserve further exploring.

The telomere connection between aging and cancer: The burden of replication stress and dysfunction

Aging is a complex process that affects individuals at the molecular, cellular, tissue, and systemic levels, arising from the cumulative effects of damage and reduced repair mechanisms. This process leads to the onset of age-related diseases, including cancer, which exhibits increased incidence with age. Telomeres, the protective caps at chromosome ends, play a crucial role in genome stability and are closely connected with aging and age-related disorders. Both excessively short and long telomere lengths may contribute to cancer development when their balance is disrupted. Fragile telomeres, characterized by abnormalities and replication stress, may provide novel insights into the connection between aging and cancer. The accumulation of fragile telomeres, possibly due to intense replicative stress, may represent a key factor. Given the dynamic nature of telomeres, large longitudinal studies are essential for understanding their role in aging and cancer susceptibility, which is crucial for developing effective strategies to promote healthy aging and mitigate cancer risk.

Involvement of TGF-β, mTOR, and inflammatory mediators in aging alterations during myxomatous mitral valve disease in a canine model

Inflammaging, a state of chronic low-grade inflammation associated with aging, has been linked to the development and progression of various disorders. Cellular senescence, a state of irreversible growth arrest, is another characteristic of aging that contributes to the pathogenesis of cardiovascular pathology. Senescent cells accumulate in tissues over time and secrete many inflammatory mediators, further exacerbating the inflammatory environment. This senescence-associated secretory phenotype can promote tissue dysfunction and remodeling, ultimately leading to the development of age-related cardiovascular pathologies, such as mitral valve myxomatous degeneration. The species-specific form of canine myxomatous mitral valve disease (MMVD) provides a unique opportunity to investigate the early causes of induction of ECM remodeling in mitral valve leaflets in the human form of MMVD. Studies have shown that in both humans and dogs, the microenvironment of the altered leaflets is inflammatory. More recently, the focus has been on the mechanisms leading to the transformation of resting VICs (qVICs) to myofibroblast-like VICs (aVICs). Cells affected by stress fall into a state of cell cycle arrest and become senescent cells. aVICs, under the influence of TGF-β signaling pathways and the mTOR complex, enhance ECM alteration and accumulation of systemic inflammation. This review aims to create a fresh new view of the complex interaction between aging, inflammation, immunosenescence, and MMVD in a canine model, as the domestic dog is a promising model of human aging and age-related diseases.

Exploring the Link Between Telomeres and Mitochondria: Mechanisms and Implications in Different Cell Types

Telomeres protect chromosome ends from damage, but they shorten with each cell division due to the limitations of DNA replication and are further affected by oxidative stress. This shortening is a key feature of aging, and telomerase, an enzyme that extends telomeres, helps mitigate this process. Aging is also associated with mitochondrial dysfunction, leading to increased reactive oxygen species (ROS) that exacerbate cellular damage and promote apoptosis. Elevated ROS levels can damage telomeres by oxidizing guanine and disrupting their regulation. Conversely, telomere damage impacts mitochondrial function, and activation of telomerase has been shown to reverse this decline. A critical link between telomere shortening and mitochondrial dysfunction is the DNA damage response, which activates the tumor suppressor protein p53, resulting in reduced mitochondrial biogenesis and metabolic disruptions. This highlights the bidirectional relationship between telomere maintenance and mitochondrial function. This review explores the complex interactions between telomeres and mitochondria across various cell types, from fibroblasts to sperm cells, shedding light on the interconnected mechanisms underlying aging and cellular function.

Impact of maternal and offspring smoking and breastfeeding on oesophageal cancer in adult offspring

Numerous risk factors for oesophageal cancer are linked to lifestyle habits, but the role of early-life factors in its incidence and mortality is unclear. Using UK Biobank data, we explore the association among breastfeeding, maternal smoking, smoking in offspring, and oesophageal cancer risk in adult offspring via multivariable Cox regression. Here, we show that being breastfed, compared with not being breastfed, is associated with a lower risk of oesophageal cancer incidence (HR: 0.83, 95% CI: 0.70-0.98) and mortality (HR: 0.74, 95% CI: 0.61-0.89) in adult offspring. Additionally, it is associated with a reduced impact of smoking in offspring on oesophageal cancer incidence (HR: 0.79, 95% CI: 0.64-0.96) and mortality (HR: 0.73, 95% CI: 0.59-0.91). We subsequently construct a polygenic risk score for oesophageal cancer to explore the influence of genetic factors. Our findings emphasize the importance of breastfeeding, and smoking cessation to prevent oesophageal cancer.

Biological aging traits mediate the association between cardiovascular health levels and all-cause and cardiovascular mortality among adults in the U.S. without cardiovascular disease

The American Heart Association's (AHA) Life's Essential 8 (LE8) metrics provide a framework for assessing cardiovascular health (CVH). This study evaluates the relationship between CVH levels from LE8 and mortality risk, considering biological aging's role. Using data from the NHANES non-CVD adult population, CVH scores were categorized as low (< 50), moderate (50-79), and high (≥ 80) per AHA guidelines. Cox regression model assessed the impact of CVH levels on all-cause and cardiovascular mortality, while examining four aging indicators as mediators. RCS explored the relationships between CVH scores and mortality risk. The model's performance was evaluated using nine machine learning algorithms, with SHAP analysis on the best model to determine CVH score components' importance. Cox regression showed that all-cause mortality rates decreased by 35% for moderate and 54% for high CVH groups compared to low CVH. The high CVH group had a 59% lower cardiovascular mortality rate. Each unit increase in CVH score reduced all-cause and cardiovascular mortality to 0.98 times. RCS analysis revealed a nonlinear trend between CVH scores and mortality risk. Biological aging indicators significantly mediated the CVH-mortality relationship, with PhenoAge (21.57%) and KDM-Age (20.33%) showing the largest effects. The XGBoost model outperformed others, with SHAP analysis ranking CVH components: physical activity, nicotine, blood pressure, BMI, lipids, healthy eating index, blood glucose, and sleep. Higher CVH levels correlate with reduced all-cause and cardiovascular mortality risk, with biological aging mediating these effects. Adhering to AHA's LE8 metrics is recommended to enhance life expectancy in the non-CVD population.

Sex differential effects of early maternal separation on PTSD susceptibility in adult rats accompanied by telomere shortening in the hippocampus

Early life stress (ELS) is thought to be a leading cause of mental disorders in adulthood, including PTSD. Recent studies have found that such stress has a gender and resilient specific effect on adult PTSD. This study aimed to assess emotion, and cognitive behavior, and to examine the sex differences and resilience of ELS on adult PTSD. At the same time, the expression of hippocampal telomere length and telomere repeat binding factors (TRF1 and TRF2) were detected to explore the mechanism of telomere length change. Rat offspring were separated from their dams (3 h/day or 6 h/day from PND2 ∼ PND14). Then, pups were treated with a single prolonged stress (SPS) procedure when they reached adulthood (PND80). Rats exposed early to MS and SPS showed anxiety-like and depression-like behaviors as well as impaired learning and memory. The rats exposed to MS3h showed reduced anxiety-like and depression-like behavior upon re-experiencing "secondary stress" compared to the SPS and MS6h groups. Behavioral results showed no significant gender difference. However, gender and SPS factors significantly affected telomere length and TRF1 and TRF2 gene expression in hippocampus. The SPS effect and MS*SPS interaction significantly impacted TRF1 and TRF2 protein expression. In conclusion, this study shows that MS has different effects on anxiety, depression, and cognitive memory deficits in rats experiencing "secondary stress" in adulthood and is accompanied by telomere shortening in the hippocampus. This reveals the potential impact of early MS on PTSD and provides a new perspective for further research in the field of psychological stress.

Great Tit (Parus major) Nestlings Have Longer Telomeres in Old-Growth Forests Than in Young Forests

Modification and deterioration of old-growth forests by industrial forestry have seriously threatened species diversity worldwide. The loss of natural habitats increases the concentration of circulating glucocorticoids and incurs chronic stress in animals, influencing the immune system, growth, survival, and lifespan of animals inhabiting such areas. In this study, we tested whether great tit (Parus major) nestlings grown in old-growth unmanaged coniferous forests have longer telomeres than great tit nestlings developing in young managed coniferous forests. This study showed that the patches of young managed coniferous forests had lower larval biomass than old-growth forests. Since insect larvae are the preferred food for great tit nestlings, the shortage of food may divert energy resources away from growth, which can show up as physiological stress, often raising the heterophil/lymphocyte (H/L) ratio. The H/L ratio revealed a significant difference in stress levels, being the highest in great tit nestlings developing in young-managed pine forests. We also found that the development of great tit nestlings in young managed forests had significantly shorter telomeres than in old-growth forests. Although nestling survival did not differ between the habitats, nestlings growing up in old-growth forests had greater telomere lengths, which can positively affect their lifespan. Our results suggest that the forest habitats affected by industrial forestry may represent ecological traps, as the development of young birds in deteriorated environments can affect the age structure of populations.

Impact of Chronic Moderate Psychological Stress on Skin Aging: Exploratory Clinical Study and Cellular Functioning

INTRODUCTION

Skin is continuously exposed to environmental external and internal factors, including psychological stress (PS). PS has been reported to trigger different dermatoses such as psoriasis, atopic dermatitis, vitiligo, alopecia areata, and acne through the release of cortisol and epinephrine.

OBJECTIVE

To clinically explore PS-induced measurable skin aging signs in subjects with moderate versus mild chronic PS, and to investigate the effect of chronic PS on DNA damage at cellular level.

METHODS

In vitro stress tests with cortisol and epinephrine, and with cortisol only on extracellular matrix (ECM) synthesis, as well as on normal human skin fibroblast and keratinocyte functioning, including skin barrier and wound healing were performed.

RESULTS

Moderately stressed subjects in the context of the clinical study had a significantly decreased antioxidant potential and impacted skin barrier integrity, as well as significantly increased signs of microrelief alterations (skin texture and fine lines) reaching an increased severity of about 32.9%. At a cellular level, DNA integrity, ECM synthesis, wound healing, and skin barrier parameters were impacted by increased stress hormone levels.

CONCLUSION

The clinical exploratory studies presented herewith, as well as the study of cell functioning under stress, have provided evidence that chronic PS significantly affects skin homeostasis and triggers skin aging.

Effect of an 18-Month Meditation Training on Telomeres in Older Adults: A Secondary Analysis of the Age-Well Randomized Controlled Trial

Background

Shorter telomeres are associated with increased risk of cognitive decline and age-related diseases. Developing interventions to promote healthy aging by preserving telomere integrity is of paramount importance. Here, we investigated the effect of an 18-month meditation intervention on telomere length (TL) measures in older people without cognitive impairment.

Methods

A total of 137 adults age ≥65 years were randomized to one of the 3 groups (meditation training, non-native language training, or passive control). We evaluated the 50th and 20th percentile TL and the percentage of critically short telomeres (<3 kbp) in peripheral blood mononuclear cells.

Results

Mixed model analysis showed a time effect indicating a general decrease on the 50th percentile TL (F = 80.72, p adjusted < .001), without a significant group effect or time × group interaction. No significant effect was detected in the 20th percentile TL or the percentage of critically short telomeres. Secondary analysis showed that only in the meditation training group 1) the 50th percentile TL positively correlated with class attendance time (r = 0.45, p adjusted < .011), 2) the 50th and 20th percentile TL positively correlated with responsiveness to the intervention, evaluated through a composite score (r = 0.46, p adjusted < .010 and r = 0.41, p adjusted = .029, respectively), and 3) lower scores on a measure of the personality trait "openness to experience" correlated with a lower percentage of critically short telomeres after the intervention (r = 0.44, p adjusted = .015).

Conclusions

In older adults, we found no evidence for a main effect of an 18-month meditation training program on TL compared with the control groups. Our findings highlight the importance of considering the impact of moderating factors when measuring the effectiveness of meditation-based trainings.

A machine learning approach identifies cellular senescence on transcriptome data of human cells in vitro

Although cellular senescence has been recognized as a hallmark of aging, it is challenging to detect senescence cells (SnCs) due to their high level of heterogeneity at the molecular level. Machine learning (ML) is likely an ideal approach to address this challenge because of its ability to recognize complex patterns that cannot be characterized by one or a few features, from high-dimensional data. To test this, we evaluated the performance of four ML algorithms including support vector machines (SVM), random forest (RF), decision tree (DT), and Soft Independent Modelling of Class Analogy (SIMCA), in distinguishing SnCs from controls based on bulk RNA sequencing data. The dataset includes 162 in vitro samples, covering three human cell types: fibroblasts, melanocytes, and keratinocytes, and three senescence inducers: irradiation, bleomycin treatment, and replication. Under tenfold and leave-one-out cross-validation, as well as independent dataset validation, all methods provided ~ 80% or higher accuracy, with SVM reaching over 99%. Similar accuracy was achieved using expert-curated gene lists, e.g., SenMayo and CellAge, instead of our algorithm-prioritized gene list using minimum redundancy-maximum relevance (mRMR). However, only a few genes overlapped between the gene sets, suggesting a wide impact of senescence on the transcriptome. Overall, our study demonstrated a proof-of-concept for identifying senescence using ML.

The relationship between mitochondrial health, telomerase activity and longitudinal telomere attrition, considering the role of chronic stress

Telomere attrition is a hallmark of biological aging, contributing to cellular replicative senescence. However, few studies have examined the determinants of telomere attrition in vivo in humans. Mitochondrial Health Index (MHI), a composite marker integrating mitochondrial energy-transformation capacity and content, may be one important mediator of telomere attrition, as it could impact telomerase activity, a direct regulator of telomere maintenance. In this observational longitudinal study, we examined in peripheral blood mononuclear cells (PBMCs), whether MHI predicted changes in telomerase activity over a 9-month period, thus impacting telomere maintenance over this same period of time. We secondarily examined the role of chronic stress, by comparing these relationships in mothers of children with an autism spectrum disorder (caregivers) vs. mothers of a neurotypical child (controls). Here we show that both chronic stress exposure and lower MHI independently predicted decreases in telomerase activity over the subsequent 9 months. Finally, changes in telomere length were directly related with changes in telomerase activity, and indirectly with MHI and chronic stress, as revealed by a path analysis. These results highlight the potential role of chronic stress and MHI as drivers of telomere attrition in human PBMCs, through an impairment of both energy-transformation capacity and telomerase production.

3D culture inhibits replicative senescence of SCAPs via UQCRC2-mediated mitochondrial oxidative phosphorylation

Stem cells derived from the apical papilla (SCAPs) play a crucial role in tooth root development and dental pulp regeneration. They are important seed cells for bone/tooth tissue engineering. However, replicative senescence remains an unavoidable issue as in vitro amplification increases. This study investigated the effect of a three-dimensional (3D) culture environment constructed with methylcellulose on SCAPs senescence. It was observed that 3D culture conditions can delay cellular senescence, potentially due to changes in mitochondrial function and oxidative phosphorylation. Transcriptome high-throughput sequencing technology revealed that the different mitochondrial states may be related to UQCRC2. Knocking down UQCRC2 expression in the 3D culture group resulted in increased production of mitochondrial reactive oxygen species, decreased mitochondrial membrane potential, and a decline in the oxygen consumption rate for oxidative phosphorylation, accelerating cell senescence. The results of this study indicated that 3D culture can mitigate SCAPs aging by maintaining UQCRC2-mediated mitochondrial homeostasis. These findings provide a new solution for the senescence of SCAPs during in vitro amplification and can promote the applications of SCAPs-based clinical translation.

Genetic determinants of telomere length and risk of aneurysmal subarachnoid hemorrhage: a bidirectional two-sample mendelian randomization study

BACKGROUND

Our objective is to investigate the potential causal relationship between telomere length (TL) and aneurysmal subarachnoid hemorrhage (aSAH) and intracranial aneurysms (IAs) by conducting a bidirectional two-sample Mendelian Randomization (MR) study.

METHODS

We utilized publicly available summary data from genome-wide association studies (GWAS) for comprehensive analysis. Telomere length-associated data were sourced from the Epidemiology Unit (IEU) GWAS database (n = 472,174), while data pertaining to intracranial aneurysms were derived from a GWAS meta-analysis conducted by Bakker et al. encompassing aneurysmal subtypes including aSAH (n = 77,074), IAs (n = 79,429), and unruptured intracranial aneurysms (uIA) (n = 74,004), all sampled from European populations. The primary method for MR analysis employed was the Inverse Variance Weighted (IVW) method. Additionally, we conducted various sensitivity analyses to assess the heterogeneity and pleiotropy of study findings. Reverse MR analysis was employed to explore potential reverse causality.

RESULTS

In the forward MR analysis, the IVW method indicated a negative association between TL and aSAH (OR = 0.636, 95% CI: 0.459-0.883, p = 0.006) as well as IAs (OR = 0.670, 95% CI: 0.499-0.900, p = 0.0079). There was no evidence of heterogeneity or horizontal pleiotropy in the forward MR analysis. Reverse MR analysis did not reveal any causal relationship between aSAH, IAs, uIA and TL.

CONCLUSIONS

In European populations, there exists a causal relationship between longer TL and reduced risks of aSAH and IAs Further research is warranted to elucidate the underlying mechanisms and the potential of TL as an intervention target for lowering the incidence of aSAH and IAs.

The role of circulating polyunsaturated fatty acids in mediating the effect of BMI on leukocyte telomere length: analysis using Mendelian randomization

BACKGROUND

polyunsaturated fatty acids (PUFAs) are a category of fatty acids that contain omega-3 and omega-6 fatty acids, which constitute a substantial portion of the Western diet and are vital for maintaining human wellness. The extent to which circulating PUFAs influence the effects of BMI on leukocyte telomere length (LTL) is unknown. Additionally, the impact of circulating PUFA on LTL remains controversial in observational studies.

METHODS

Using publicly accessible datasets, a genome-wide association study (GWAS) was carried out to determine genetic association estimates for BMI, circulating PUFAs, and LTL. The circulating PUFAs considered were omega-3 PUFAs (i.e., docosahexaenoic acid (DHA) and total omega-3 PUFAs) and omega-6 PUFAs (i.e., linoleic acid (LA) and total omega-6 PUFAs). Two-sample Mendelian randomization (MR) was used to investigate the causal relationships between BMI and PUFA with LTL. Additionally, we examined whether certain PUFA mediate the impact of BMI on LTL.

RESULTS

None of the evidence supported a causal effect of genetically predicted DHA and total omega-3 PUFA on LTL (DHA: β = 0.001, 95% CI: -0.023 to 0.026, p = 0.926; total omega-3 PUFA: β = 0.008, 95% CI: -0.013 to 0.029, p = 0.466). After conducting sensitivity analyses to account for various models of horizontal pleiotropy, the causal association between higher levels of LA and longer LTL persisted (β = 0.034, 95% CI 0.016 to 0.052, p < 0.001). Adjusting for LA in genetics reduced the effect of BMI on LTL from β = -0.039 (95% CI: -0.058 to -0.020, p < 0.001) to -0.034 (95% CI: -0.054 to -0.014, p < 0.001).

CONCLUSIONS

This MR study indicates that an increase in genetically predicted circulating LA levels is associated with longer LTL. Additionally, it appears that circulating LA levels play a role in mediating some of the impact that BMI has on LTL.

High school diploma is associated with longer postpartum leukocyte telomere length in a cohort of primarily Latina women

OBJECTIVE

This study investigates correlates of maternal leukocyte telomere length (LTL) in the immediate postpartum period using a cross-sectional study design from an existing prospective longitudinal birth cohort of primarily Latina women. The study focuses on the role of maternal health and dietary habits in pregnancy and maternal education level and LTL at delivery.

STUDY DESIGN

Latina mothers were recruited during the immediate postpartum period prior to 24 h at two San Francisco hospitals and dried blood spots were collected for LTL analysis via quantitative polymerase chain reaction (qPCR). We used multivariable linear regression models to determine independent predictors of maternal LTL during the postpartum period.

RESULTS

In multivariable regression models, increasing maternal age was associated with shorter LTL during the immediate postpartum period (Coeff - 0.015; p < 0.01) whereas having a high school diploma was associated with longer LTL versus not having graduated from high school (Coeff 0.12; p < 0.01).

CONCLUSION

Maternal education level as a potential marker of exposure to life stressors and socioeconomic status was associated with maternal LTL after adjusting for age and other potential confounders in women of reproductive age.

Sex-specific modulating role of social support in the associations between oxidative stress, inflammation, and telomere length in older adults

Telomere length, a biomarker of human aging, is related to adverse health outcomes. Growing evidence indicates that oxidative stress and inflammation contributes to telomere shortening, whereas social support may protect from telomere shortening. Despite sex differences in telomere length and social support, little is known about whether there are sex differences in the relationship between oxidative stress/inflammation and telomere length, and sex-specific moderating roles of social support in older adults. Using data from the National Health and Nutrition Examination Survey (NHANES) 1999-2002, this study assessed whether the associations between oxidative stress/inflammation and telomere length vary with sex and explored social support as a moderator in these associations among 2289 older adults. Oxidative stress was measured based on serum Gamma-glutamyl transferase (GGT), and inflammation was measured based on C-reactive protein (CRP). After adjusting for the covariates, GGT was significantly associated with telomere length in females only (β =  - 0.037, 95% CI =  - 0.070, - 0.005), while CRP was associated with telomere length in males only (β =  - 0.019, 95% CI =  - 0.035, - 0.002). Moreover, high social support mitigated the negative association between GGT and telomere length, which was more evident in females. Furthermore, social support moderated the association between CRP and telomere length in males aged 70 and above. Our findings indicated that biological mechanisms related to telomere length may vary with sex, while social support plays a sex-specific moderating role.

Autophagy in the Cellular Consequences of Tobacco Smoking: Insights into Senescence

Smoking is a significant contributing factor to the development of many complex diseases. One of the most important stimuli for aging in the human body is constant exposure to environmental factors such as cigarette smoke. Free radicals in cigarette smoke cause reactive oxygen species production at the cellular level and induce inflammatory responses. The respiratory system of smokers exhibits age-related characteristics, such as enhanced oxidative stress, accumulated damaged proteins, and increased inflammation. Autophagy is triggered by tobacco smoke as a protective mechanism to prevent and reduce molecular stress. However, smoking can interfere with the normal functioning of autophagy in various ways. Smoking-induced impairment of autophagy leads to irreversible cellular damage accumulation, causing cells to undergo cellular aging or senescence. Senescent cells lose their ability to divide and display a distinct secretory phenotype called the senescence-associated secretory phenotype (SASP) and produce numerous growth factors, immune modulators, and inflammatory cytokines. This review discusses the effects of tobacco smoke exposure on autophagy alteration, cellular aging, and senescence induction in exposed animal models, as well as in exposed epithelial and immune cells in the body.

Psychological stressors involved in the pathogenesis of premature ovarian insufficiency and potential intervention measures

Premature ovarian insufficiency (POI) is a common gynecological endocrine disease, which seriously affects women's physical and mental health and fertility, and its incidence is increasing year by year. With the development of social economy and technology, psychological stressors such as anxiety and depression caused by social, life and environmental factors may be one of the risk factors for POI. We used PubMed to search peer-reviewed original English manuscripts published over the last 10 years to identify established and experimental studies on the relationship between various types of stress and decreased ovarian function. Oxidative stress, follicular atresia, and excessive activation of oocytes, caused by Stress-associated factors may be the main causes of ovarian function damage. This article reviews the relationship between psychological stressors and hypoovarian function and the possible early intervention measures in order to provide new ideas for future clinical treatment and intervention.

When do the pathological signs become evident? Study of human mesenchymal stem cells in MDPL syndrome

Aging syndromes are rare genetic disorders sharing the features of accelerated senescence. Among these, Mandibular hypoplasia, Deafness and Progeroid features with concomitant Lipodystrophy (MDPL; OMIM #615381) is a rare autosomal dominant disease due to a de novo in-frame deletion in POLD1 gene, encoding the catalytic subunit of DNA polymerase delta. Here, we investigated how MSCs may contribute to the phenotypes and progression of premature aging syndromes such as MDPL. In human induced pluripotent stem cells (hiPSCs)-derived MSCs of three MDPL patients we detected several hallmarks of senescence, including (i) abnormal nuclear morphology, (ii) micronuclei presence, (iii) slow cell proliferation and cell cycle progression, (iv) reduced telomere length, and (v) increased levels of mitochondrial reactive oxygen species (ROS). We newly demonstrated that the pathological hallmarks of senescence manifest at an early stage of human development and represent a warning sign for the progression of the disease. Dissecting the mechanisms underlying stem cell dysfunction during aging can thereby contribute to the development of timely pharmacological therapies for ameliorating the pathological phenotype.

Relationship between serum carotenoids and telomere length in overweight or obese individuals

Background

Previous researches have demonstrated an association between carotenoids and elongated telomeres. Nonetheless, there is scant scientific evidence examining this relationship in individuals who are overweight or obese, a demographic more predisposed to accelerated aging. This study aims to elucidate the correlation between serum carotenoid concentrations and telomere length within this population group.

Methods

Data were sourced from the 2001-2002 National Health and Nutrition Examination Survey, encompassing 2,353 overweight or obese participants. The levels of α-carotene, β-carotene (both trans and cis isomers), β-cryptoxanthin, lutein/zeaxanthin, and trans-lycopene were quantified via high-performance liquid chromatography. Telomere length was assessed using quantitative polymerase chain reaction.

Results

Following adjustment for potential confounders, telomere length exhibited an increase of 1.83 base pairs (bp) per unit elevation in β-carotene levels (β = 1.83; 95% CI: 0.48, 3.18). Within the fully adjusted model, telomere length incremented by 1.7 bp per unit increase in serum β-carotene among overweight individuals (β = 1.7; 95% CI: 0.1, 3.3), and by 2.6 bp per unit increase among obese individuals (β = 2.6; 95% CI: 0.1, 5.0). Furthermore, restricted cubic spline analysis revealed a linear relationship between β-carotene levels and telomere length, whereas a non-linear association was observed between β-cryptoxanthin levels and telomere length.

Conclusion

This investigation indicates that higher serum β-carotene concentrations are linked with extended telomere length in overweight and obese populations in the United States. These findings warrant further validation through prospective studies.

Causal relationship between leukocyte telomere length and two cardiomyopathies based on a bidirectional Mendelian randomization approach

This study aims to employ the Mendelian randomization (MR) approach to investigate the relationship between leukocyte telomere length (TL) and 2 prevalent forms of cardiomyopathies. Using R software (4.3.1) for MR study, independent genetic variants associated with leukocyte TL were extracted from the Integrative Epidemiology Unit database, while cardiomyopathies data were pooled from FinnGen and European Bioinformatics Institute databases. Analytical methodologies included inverse-variance weighting, MR-Egger regression, and weighted median methods. Further analyses involved MR-Egger intercept and MR-PRESSO for handling horizontal pleiotropy and Cochran Q test for study heterogeneity. Our forward Mendelian randomization study indicates a positive correlation between longer leukocyte TL and the risk of 2 forms of cardiomyopathies: the longer the leukocyte telomere, the higher is the risk of cardiomyopathies. Specifically, for hypertrophic obstructive cardiomyopathy the OR is 2.23 (95% CI: 1.19-4.14, P = .01), for hypertrophic cardiomyopathy the OR is 1.80 (95% CI: 1.14-2.85, P = .01), and for dilated cardiomyopathy the OR is 1.32 (95% CI: 1.01-1.71, P = .04). In contrast, our reverse Mendelian randomization showed that cardiomyopathies were not directly associated with TL, and the inverse-variance-weighted test was not statistically significant for any of the 3 (P > .05). The reliability tests for the forward Mendelian randomization, including both MR-Egger intercept and MR-PRESSO tests, show no evidence of horizontal pleiotropy, and Cochran Q test indicates no heterogeneity. The "leave-one-out" sensitivity analysis revealed no outlier genes. The reliability tests for the reverse Mendelian randomization, including both MR-Egger intercept and MR-PRESSO tests, also indicate no genetic pleiotropy. Despite the heterogeneity shown in our study between hypertrophic cardiomyopathy and leukocyte TL, the sensitivity analysis did not identify any anomalies. Our Mendelian randomization study suggests that longer leukocyte TL is associated with an increased risk of hypertrophic obstructive cardiomyopathy, hypertrophic cardiomyopathy, and dilated cardiomyopathy. However, the onset of these 2 kinds of disease does not directly lead to changes in leukocyte TL.

Yoga as an intervention for stress: a meta-analysis

The escalating stress epidemic in modern society has raised concerns about its impact on physical and mental health, prompting the need for effective interventions. Yoga, a multifaceted mind-body practice, has gained recognition for its potential in mitigating perceived stress. Our meta-analysis aimed to estimate yoga's impact on lowering perceived stress as measured by the Perceived Stress Scale. We identified 36 studies meeting inclusion criteria and found a statistically significant moderate effect of yoga on reducing perceived stress (g = 0.48, 95% CI = 0.29-0.66). Our analysis uncovered substantial heterogeneity (Q = 117.33, p < .001), with 74.90% of the variation in effect sizes attributed to study characteristics. In planned moderator analyses, we hypothesised that yoga with breathwork, relaxation, high stress symptoms, greater number of hours practiced, and studies conducted in India would yield larger effects. Stress severity was shown to be statistically significant. However, the remaining hypotheses were not supported. Additionally, we examined five exploratory moderator variables, which did not yield significant results. Further research is needed to elucidate the source of heterogeneity across studies and reveal recommendations for specific populations.

The Val66Met variant of brain-derived neurotrophic factor is linked to reduced telomere length in a military population: a pilot study

In military populations, gene-environment interactions can influence performance and health outcomes. Brain-derived neurotrophic factor (BDNF) is a central nervous system protein that is important for neuronal function and synaptic plasticity. A BDNF single nucleotide polymorphism, rs6265, leads to an amino acid substitution of valine (Val) with methionine (Met) at codon 66 (Val66Met), which may influence an individual's response to occupational stress, and predispose military members to psychological disorders. Telomere length (TL), a novel measure of biological aging, can be used as a biomarker of stress. Accordingly, telomere shortening may be a surrogate indicator of physiological weathering due to chronic disease and stressful life events. To increase our understanding about the potential effect of the Val66Met mutation on the human stress response, we evaluated the relationships between Val66Met, TL, and mental health symptoms in a military population. In this pilot study (N = 164), we observed an association between Val66Met and reduced TL (p = 0.048). There was no relationship between Val66Met and mental health symptoms. These results support the investigation of gene-environment interactions, and their potential influence on TL due to occupational stress such as military service.

Aberrant telomeric structures and serum markers of telomere dysfunction in healthy aging: a preliminary study

Telomeres undergo a progressive shortening process as individuals age, and it has been proposed that severely shortened and dysfunctional telomeres play a role in the aging process and the onset of age-related diseases in human beings. An emerging body of evidence indicates that the shortening of telomeres in cultured human cells is also influenced by other replication defects occurring within telomeric repeats. These abnormalities can be detected on metaphase chromosomes. Recent studies have also identified a set of serological markers for telomere dysfunction and DNA damage (elongation factor 1α [EF-1α], stathmin, and N-acetyl-glucosaminidase). With this study, the correlation between telomere abnormalities (by FISH) and these biomarkers as measured in blood serum (by ELISA) from a cohort of 22 healthy subjects at different ages (range 26-101 years) was analyzed. A strong positive correlation between aging and the presence of aberrant telomere structures, sister telomere loss (STL), and sister telomere chromatid fusions (STCF) was detected. When serum markers of telomere dysfunction were correlated with telomere abnormalities, we found that stathmin correlated with total aberrant telomeres structures (r = 0.431, p = 0.0453) and STCF (r = 0.533, p = 0.0107). These findings suggest that serum stathmin can be considered an easy-to-get marker of telomere dysfunction and may serve as valuable indicators of aging.

Lutein protects senescent ciliary muscle against oxidative stress through the Keap1/Nrf2/ARE pathway

BACKGROUND

Aging-induced decline in ciliary muscle function is an important factor in visual accommodative deficits in elderly adults. With this study, we provide an innovative investigation of the interaction between ciliary muscle aging and oxidative stress.

METHODS

Tricolor guinea pigs were used for the experiments in vivo and primary guinea pig ciliary smooth muscle cells were used for the experiments in vitro.

RESULTS

We enriched for genes associated with muscle-aging-lutein relationship using bioinformatics, including Nuclear factor-erythroid 2-related factor-2 (Nrf2), Glutathione Peroxidase (GPx) gene family, Superoxide Dismutase (SOD) gene family, NAD(P)H: Quinone Oxidoreductase 1 (NQO1) and Heme Oxygenase-1 (HO-1). After gavage to aged guinea pigs, lutein reduced Reactive Oxygen Species (ROS) and P21 levels in senescent ciliary muscle; lutein decreased refractive error and restored accommodation of the eye. In addition, lutein increased GPx, SOD, and Catalase (CAT) levels in serum; lutein increased GPx and CAT levels in ciliary bodies. Lutein regulated the expression of proteins such as Nrf2, Kelch-like ECH-associated protein 1 (Keap1), and downstream proteins in senescent ciliary bodies. Similarly, guinea pig ciliary muscle cell senescence was associated with oxidative stress. In vitro, 100 μM lutein reversed the damage caused by 800 μM H2O2; it reduced Senescence-Associated β-galactosidase (SA-β-Gal) and ROS activites, cell apoptosis and cell migration. Also, lutein increased the expression of smooth muscle contractile proteins. Lutein also increased the expression of Nrf2, GPx2, NQO1 and HO-1, decreased the expression of Keap1. A reduction in Nrf2 activity led to a reduction in the ability of lutein to activate antioxidant enzymes in the cells, thus reducing its inhibitory effect on cell senescence.

CONCLUSION

lutein improved resistance to oxidative stress in senescent ciliary muscle in vivo and in vitro by regulating the Keap1/Nrf2/Antioxidant Response Element pathway. We have innovatively demonstrated the molecular pharmacological mechanism by which lutein reverse age-related ciliary muscle systolic and diastolic deficits.

Proanthocyanidins protects 3-NPA-induced ovarian function decline by activating SESTRIN2-NRF2-mediated oxidative stress in mice

Abnormal apoptosis of ovarian cells caused by oxidative stress is an important cause of premature ovarian failure (POF). Previous studies revealed that proanthocyanidins (PCs) are powerful natural antioxidants that can safely prevent oxidative damage in humans. However, the protective effect and mechanism of PCs on ovarian function during the course of POF remain unknown. In this study, female mice were injected with 3-nitropropionic acid (3-NPA) to establish an ovarian oxidative stress model; at the same time, the mice were treated with PC via gavage. Thereafter, the expression of various apoptosis genes, hormones, and related molecules was assessed. Compared with those in the control group, the ovarian index, follicle count at all levels, expression of MVH, PCNA and BCL2, and estradiol (E2) and progesterone (P) levels were significantly lower in the POF group, but significant recovery was observed in terms of MVH and PCNA expression and E2 and P levels in the POF + PCs group. The apoptosis marker genes BAX and ROS were significantly increased in the POF group but were notably restored in the POF + PCs group. In addition, the expression of Sestrin2, an antiapoptotic protein, was significantly increased in the PCs treatment group, as were the upstream and downstream regulatory factors NRF2 and SOD2, and the indices of the Sestrin2 overexpression group were similar to those of the PCs treatment group. In summary, these findings suggest that PCs have potential as innovative therapeutic agents for preventing and treating POF by activating the protective SESTRIN2-NRF2 pathway against oxidative stress.

Work-Related Stress and Coping: A Comparative Analysis of On-Site and Office-Based Workers in UK Building Construction

BACKGROUND

There are increasing mental health concerns in the construction industry workforce, with stress being a primary concern. This qualitative study investigates stress experiences and the management of stress in office-based and on-site workers in the UK building construction sector. This study can provide key insights for construction, but also potentially other industries which struggle with high stress levels among their employees.

METHODS

A total of 40 semi-structured interviews (20 on-site/20 office-based) were conducted at large-scale building construction projects in the southeast UK. Framework method analysis was used to derive an understanding of stress in the workplace and coping strategies.

RESULTS

The study identified two major themes: the negative influence of work stress on personal and professional wellbeing, and the management of stress through proactive and reactive coping strategies. Results indicated that on-site workers frequently cited high workloads, tight deadlines, and safety concerns, whereas office-based workers tended to highlight job complexity and organisational pressures. Both population sub-groups reported stress affecting their work performance, with site-workers having the added concern of physical health and safety. Coping strategies among workers tended to rely on support networks, outside-the-workplace hobbies, and boundary-setting, among others.

CONCLUSIONS

Stress remains a significant problem in the workplace and affects wellbeing; however, there are ways to mitigate the stress. Our findings could provide a foundation for intervention development.

Integrated miRNA-mRNA analysis uncovers immediate-early response to salinity stress in gill-derived cell line of Gymnocypris przewalskii

Salinity adaptation is an important issue in aquaculture. Understanding the immediate-early response to salinity stress helps in comprehending this process. In vitro experiments using cell lines can explain cell-independent reactions without the involvement of hormones in vivo. In this study, salinity stress experiments were conducted using cell line derived from the gills of Gymnocypris przewalskii (GPG cell line) to isolate immediate-early response-related genes and miRNAs using transcriptomics, followed by bioinformatics analysis. The results showed that intracellular free Ca2+ appeared to be a key factor in cell sensing and initiating downstream cell signaling in response to external salinity. Additionally, cell apoptosis was the most common feature of salinity stress, with multiple signaling pathways involved in salinity-induced cell apoptosis. Furthermore, MiRNAs played a crucial role in the rapid response to salinity stress by selectively inhibiting the expression of specific genes. Additionally, for the first time in the G. przewalskii genome, Tf2 and TY3 families of transposons were found to have responsive roles to the external salinity stress. This study contributes to a better understanding of osmotic sensing in G. przewalskii and provides theoretical assistance for improving salinity adaptation in aquaculture fish species.

Low-power red laser and blue LED modulate telomere maintenance and length in human breast cancer cells

Cancer cells have the ability to undergo an unlimited number of cell divisions, which gives them immortality. Thus, the cancer cell can extend the length of its telomeres, allowing these cells to divide unlimitedly and avoid entering the state of senescence or cellular apoptosis. One of the main effects of photobiomodulation (PBM) is the increase in the production of adenosine triphosphate (ATP) and free radicals, mainly reactive oxygen species (ROS). Existent data indicates that high levels of ROS can cause shortening and dysfunctional telomeres. Therefore, a better understanding of the effects induced by PBM on cancer cell telomere maintenance is needed. This work aimed to evaluate the effects of low-power red laser (658 nm) and blue LED (470 nm) on the TRF1 and TRF2 mRNA levels and telomere length in human breast cancer cells. MCF-7 and MDA-MB-231 cells were irradiated with a low-power red laser (69 J cm-2, 0.77 W/cm-2) and blue LED (482 J cm-2, 5.35 W/cm-2), alone or in combination, and the relative mRNA levels of the genes and telomere length were assessed by quantitative reverse transcription polymerase chain reaction. The results suggested that exposure to certain red laser and blue LED fluences decreased the TRF1 and TRF2 mRNA levels in both human breast cancer cells. Telomere length was increased in MCF-7 cells after exposure to red laser and blue LED. However, telomere length in MDA-MB-231 was shortened after exposure to red laser and blue LED at fluences evaluated. Our research suggests that photobiomodulation induced by red laser and low-power blue LED could alter telomere maintenance and length.

The researcher's guide to selecting biomarkers in mental health studies

Clinical mental health researchers may understandably struggle with how to incorporate biological assessments in clinical research. The options are numerous and are described in a vast and complex body of literature. Here we provide guidelines to assist mental health researchers seeking to include biological measures in their studies. Apart from a focus on behavioral outcomes as measured via interviews or questionnaires, we advocate for a focus on biological pathways in clinical trials and epidemiological studies that may help clarify pathophysiology and mechanisms of action, delineate biological subgroups of participants, mediate treatment effects, and inform personalized treatment strategies. With this paper we aim to bridge the gap between clinical and biological mental health research by (1) discussing the clinical relevance, measurement reliability, and feasibility of relevant peripheral biomarkers; (2) addressing five types of biological tissues, namely blood, saliva, urine, stool and hair; and (3) providing information on how to control sources of measurement variability.

Telomere biology and its maintenance in schizophrenia spectrum disorders: Exploring links to cognition

OBJECTIVE

Contemporary research suggests reduced telomere length in schizophrenia spectrum disorders (SZ) compared to age-adjusted non-affected individuals. However, the role of telomere maintenance and telomere repair in SZ is poorly understood as well as the involvement of telomere biology in cognitive abnormalities in SZ.

METHODS

The study consisted of 758 participants (SZ [n = 357] and healthy controls, HC [n = 401]) collected as part of the Norwegian TOP study. Participants were assessed with standardized neuropsychological tests measuring five cognitive domains. Leucocyte telomere length (TL) was measured via blood and determined by quantitative real-time Polymerase Chain Reaction (qPCR) providing a telomere to single copy ratio (T/S ratio), used to estimate the mean telomere length. Telomerase activity was assessed by the expression levels of the Telomerase Reverse Transcriptase (TERT) and Telomerase RNA Component (TERC) genes. To assess telomere maintenance and telomere repair we calculated the telomerase expression to TL ratio (TERT/TL and TERC/TL respectively).

RESULTS

Patients had reduced TERT (F = 5.03, p = 0.03), but not TERC expression (F = 1.04, p = 0.31), and higher TERT/TL (F = 6.68, p = 0.01) and TERC/TL (F = 6.71, p = 0.01), adjusted for age, sex, and ethnicity. No statistically significant association was observed between any of the telomere biology markers and the cognitive domains (p > 0.05).

CONCLUSION

Our study shows changes in TERT expression and telomere maintenance and telomere repair in SZ compared HC. However, the role of telomere biology in the mechanism underlying cognitive impairment in psychosis seems limited.

Effects of persistent organic pollutants on telomere dynamics are sex and age-specific in a wild long-lived bird

Chemical pollution is a major man-made environmental threat to ecosystems and natural animal populations. Of concern are persistent organic pollutants (POPs), which can persist in the environment for many years. While bioaccumulating throughout the lives of wild animals, POPs can affect their health, reproduction, and survival. However, measuring long-term effects of POPs in wild populations is challenging, and therefore appropriate biomarkers are required in wildlife ecotoxicology. One potential target is telomere length, since telomere preservation has been associated to survival and longevity, and stressors as chemical pollution can disrupt its maintenance. Here, we investigated the effects of different classes of POPs on relative telomere length (RTL) and its rate of change (TROC) in wild long-lived Alpine swifts (Tachymarptis melba). As both RTL and TROC are often reported to differ between sexes and with chronological age, we tested for sex- and age-specific (pre-senescent vs. senescent, ≥ 9 age of years, individuals) effects of POPs. Our results showed that senescent females presented longer RTL and elongated telomeres over time compared to pre-senescent females and males. These sex- and age-related differences in RTL and TROC were influenced by POPs, but differently depending on whether they were organochlorine pesticides (OCPs) or industrial polychlorinated biphenyls (PCBs). OCPs (particularly drins) were negatively associated with RTL, with the strongest negative effects being found in senescent females. Conversely, PCBs led to slower rates of telomere shortening, especially in females. Our study indicates diametrically opposed effects of OCPs on RTL and PCBs on TROC, and these effects were more pronounced in females and senescent individuals. The mechanisms behind these effects (e.g., increased oxidative stress by OCPs; upregulation of telomerase activity by PCBs) remain unknown. Our results highlight the importance in wildlife ecotoxicology to account for sex- and age-related effects when investigating the health effects of pollutants on biomarkers such as telomeres.

Exposure to four typical heavy metals induced telomere shortening of peripheral blood mononuclear cells in relevant with declined urinary aMT6s in rats

Environmental heavy metals pollution have seriously threatened the health of human beings. An increasing number of researches have demonstrated that environmental heavy metals can influence the telomere length of Peripheral Blood Mononuclear Cells (PBMCs), which implicate biological aging as well as predicts diseases. Our previous study has shown that methylmercury (MeHg)-induced telomere shortening in rat brain tissue was associated with urinary melatonin metabolite 6-sulfatoxymelatonin (aMT6s) levels. Here, we aimed to further elucidate the impact of 4 typical heavy metals (As, Hg, Cd and Pb) on telomere length of PBMCs and their association with urinary aMT6s in rats. In this study, eighty-eight male Sprague-Dawley rats were randomized grouped into eleven groups. Among them, forty 3-month-old (young) and forty 12-month-old (middle-aged) rats were divided into young or middle-aged control groups as well as typical heavy metals exposed groups, respectively. Eight 24-month-old rats (old) was divided into aging control group. The results showed that MeHg exposure in young rats while sodium arsenite (iAs), MeHg, cadmium chloride (CdCl2), lead acetate (PbAc) exposure in middle-aged rats for 3 months significantly reduced the levels of and urinary aMT6s, as well as telomere length of PBMCs. In addition, they also induced abnormalities in serum oxidative stress (SOD, MDA and GPx) and inflammatory (IL-1β, IL-6 and TNF-α) indicators. Notably, there was a significant positive correlation between declined level of urinary aMT6s and the shortening of telomere length in PBMCs in rats exposed to 4 typical heavy metals. These results suggested that 4 typical heavy metals exposure could accelerate the reduction of telomere length of PBMCs partially by inducing oxidative stress and inflammatory in rats, while ageing may be an important synergistic factor. Urinary aMT6s detection may be a alternative method to reflect telomere toxic effects induced by heavy metal exposure.

Searching for Beauty and Health: Aging in Women, Nutrition, and the Secret in Telomeres

Women typically outlive men, yet they often experience greater frailty and a higher incidence of chronic diseases as they age. By exploring the biological foundations of aging, with a particular focus on telomere dynamics, this manuscript aims to describe how dietary and lifestyle choices can significantly influence the aging process. The review comprehensively examines current research, underscoring the power of nutrition to counteract age-related changes, support healthy aging, and maintain vitality and beauty in women. The exploration of telomeres-the protective caps at the ends of chromosomes-reveals how they serve as markers of cellular aging and are potential targets for interventions aimed at enhancing women's longevity and quality of life. This study also emphasizes the importance of sex-specific approaches and precision medicine in understanding the unique health challenges women face as they age. By proposing targeted strategies, the review seeks to address these challenges, offering insights into preventive measures that can foster resilience, promote well-being, and extend healthy life expectancy in women. Ultimately, this work provides a sophisticated understanding of the aging process in women, highlighting the pivotal role of tailored interventions in preserving both health and beauty.

Oxidative Stress and Age-Related Tumors

Oxidative stress is the result of the imbalance between reactive oxygen and nitrogen species (RONS), which are produced by several endogenous and exogenous processes, and antioxidant defenses consisting of exogenous and endogenous molecules that protect biological systems from free radical toxicity. Oxidative stress is a major factor in the aging process, contributing to the accumulation of cellular damage over time. Oxidative damage to cellular biomolecules, leads to DNA alterations, lipid peroxidation, protein oxidation, and mitochondrial dysfunction resulting in cellular senescence, immune system and tissue dysfunctions, and increased susceptibility to age-related pathologies, such as inflammatory disorders, cardiovascular and neurodegenerative diseases, diabetes, and cancer. Oxidative stress-driven DNA damage and mutations, or methylation and histone modification, which alter gene expression, are key determinants of tumor initiation, angiogenesis, metastasis, and therapy resistance. Accumulation of genetic and epigenetic damage, to which oxidative stress contributes, eventually leads to unrestrained cell proliferation, the inhibition of cell differentiation, and the evasion of cell death, providing favorable conditions for tumorigenesis. Colorectal, breast, lung, prostate, and skin cancers are the most frequent aging-associated malignancies, and oxidative stress is implicated in their pathogenesis and biological behavior. Our aim is to shed light on the molecular and cellular mechanisms that link oxidative stress, aging, and cancers, highlighting the impact of both RONS and antioxidants, provided by diet and exercise, on cellular senescence, immunity, and development of an antitumor response. The dual role of ROS as physiological regulators of cell signaling responsible for cell damage and diseases, as well as its use for anti-tumor therapeutic purposes, will also be discussed. Managing oxidative stress is crucial for promoting healthy aging and reducing the risk of age-related tumors.

The association of psychological and trauma-related factors with biological and facial aging acceleration: evidence from the UK Biobank

BACKGROUND

Psychological and trauma-related factors are associated with many diseases and mortality. However, a comprehensive assessment of the association between psycho-trauma exposures and aging acceleration is currently lacking.

METHODS

Using data from 332,359 UK Biobank participants, we calculated biological aging acceleration, indexed by the presence of leukocyte telomere length (LTL) deviation (i.e., the difference between genetically determined and observed LTL > 0). The acceleration of facial aging (i.e., looking older than the chronological age) was assessed using a self-report question. Then, we estimated the associations of each psycho-trauma factor with biological and facial aging acceleration, using logistic regression models adjusted for multiple important covariates. Furthermore, restricted to 99,180 participants with complete psychological and trauma-related data, we identified clusters of individuals with distinct psycho-trauma patterns using the latent class analysis method and assessed their associations with aging acceleration using similar models.

RESULTS

We observed most of the studied psycho-trauma factors were associated with biological and facial aging acceleration. Compared to the "Absence of trauma and psychopathology" cluster, the "adverse childhood experiences (ACEs) with psychopathology" cluster showed strong associations with those aging measurements (odds ratio [OR] = 1.13 [1.05 - 1.23] for biological and 1.52 [1.18 - 1.95] for facial aging acceleration), while no such association was observed for the "ACEs without psychopathology" cluster (1.04 [0.99 - 1.09] and 1.02 [0.84 - 1.24].

CONCLUSIONS

Our study demonstrated significant associations of psycho-trauma factors with both biological and facial aging acceleration. The differential aging consequences observed among ACEs exposed individuals with and without psychopathology prompt interventions aimed to improve individuals' psychological resilience to prevent aging acceleration.

Telomere stabilization by metformin mitigates the progression of atherosclerosis via the AMPK-dependent p-PGC-1α pathway

Telomere dysfunction is a well-known molecular trigger of senescence and has been associated with various age-related diseases, including atherosclerosis. However, the mechanisms involved have not yet been elucidated, and the extent to which telomeres contribute to atherosclerosis is unknown. Therefore, we investigated the mechanism of metformin-induced telomere stabilization and the ability of metformin to inhibit vascular smooth muscle cell (VSMC) senescence caused by advanced atherosclerosis. The present study revealed that metformin inhibited the phenotypes of atherosclerosis and senescence in VSMCs. Metformin increased the phosphorylation of AMPK-dependent PGC-1α and thus increased telomerase activity and the protein level of TERT in OA-treated VSMCs. Mechanistically, the phosphorylation of AMPK and PGC-1α by metformin not only enhanced telomere function but also increased the protein level of TERT, whereas TERT knockdown accelerated the development of atherosclerosis and senescent phenotypes in OA-treated VSMCs regardless of metformin treatment. Furthermore, the in vivo results showed that metformin attenuated the formation of atherosclerotic plaque markers in the aortas of HFD-fed ApoE KO mice. Although metformin did not reduce plaque size, it inhibited the phosphorylation of the AMPK/PGC-1α/TERT signaling cascade, which is associated with the maintenance and progression of plaque formation, in HFD-fed ApoE KO mice. Accordingly, metformin inhibited atherosclerosis-associated phenotypes in vitro and in vivo. These observations show that the enhancement of telomere function by metformin is involved in specific signaling pathways during the progression of atherosclerosis. These findings suggest that telomere stabilization by metformin via the AMPK/p-PGC-1α pathway might provide a strategy for developing therapeutics against vascular diseases such as atherosclerosis.