Stress and telomere shortening: Insights from cellular mechanisms

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.

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.

Polystyrene microplastics facilitate renal fibrosis through accelerating tubular epithelial cell senescence

Microplastics (MPs), emerging contaminants, are easily transported and enriched in the kidney, suggesting the kidney is susceptible to the toxicity of MPs. In this study, we explored the toxicity of MPs, including unmodified polystyrene (PS), negative-charged PS-SO3H, and positive-charged PS-NH2 MPs, in mice models for 28 days at a human equivalent concentration. The results showed MPs significantly increased levels of UREA, urea nitrogen (BUN), creatinine (CREA), and uric acid (UA) levels in serum and white blood cells, protein, and microalbumin in urine. In the kidney, MPs triggered persistent inflammation and renal fibrosis, which was caused by the increased senescence of tubular epithelial cells. Moreover, we identified the critical role of the Klotho/Wnt/β-catenin signaling pathway in the process of MPs induced senescence of tubular epithelial cells, promoting the epithelial-mesenchymal transformation of epithelial cells. MPs supported the secretion of TGF-β1 by senescent epithelial cells and induced the activation of renal fibroblasts. On the contrary, restoring the function of Klotho can alleviate the senescence of epithelial cells and reverse the activation of fibroblasts. Thus, our study revealed new evidence between MPs and renal fibrosis, and adds an important piece to the whole picture of the plastic pollution on people's health.

Ciprofloxacin Accelerates Angiotensin-II-Induced Vascular Smooth Muscle Cells Senescence Through Modulating AMPK/ROS pathway in Aortic Aneurysm and Dissection

Aortic aneurysm and dissection (AAD) is a cardiovascular disease that poses a severe threat to life and has high morbidity and mortality rates. Clinical and animal-based studies have irrefutably shown that fluoroquinolones, a commonly prescribed antibiotic for treating infections, significantly increase the risk of AAD. Despite this, the precise mechanism by which fluoroquinolones cause AAD remains unclear. Therefore, this study aims to investigate the molecular mechanism and role of Ciprofloxacin definitively-a type of fluoroquinolone antibiotic-in the progression of AAD. Aortic transcriptome data were collected from GEO datasets to detect the genes and pathways expressed differently between healthy donors and AAD patients. Human primary Vascular Smooth Muscle Cells (VSMCs) were isolated from the aorta. After 72 h of exposure to 110ug/ml Ciprofloxacin or 100 nmol/L AngII, either or combined, the senescent cells were identified through SA-β-gal staining. MitoTracker staining was used to examine the morphology of mitochondria in each group. Cellular Reactive Oxygen Species (ROS) levels were measured using MitoSox and DCFH-DA staining. Western blot assay was performed to detect the protein expression level. We conducted an analysis of transcriptome data from both healthy donors and patients with AAD and found that there were significant changes in cellular senescence-related signaling pathways in the latter group. We then isolated and identified human primary VSMCs from healthy donors (control-VSMCs) and patients' (AAD-VSMCs) aortic tissue, respectively. We found that VSMCs from patients exhibited senescent phenotype as compared to control-VSMCs. The higher levels of p21 and p16 and elevated SA-β-gal activity demonstrated this. We also found that pretreatment with Ciprofloxacin promoted angiotensin-II-induced cellular senescence in control-VSMCs. This was evidenced by increased SA-β-gal activity, decreased cell proliferation, and elevation of p21 and p16 protein levels. Additionally, we found that Angiotensin-II (AngII) induced VSMC senescence by promoting ROS generation. We used DCFH-DA and mitoSOX staining to identify that Ciprofloxacin and AngII pretreatment further elevated ROS levels than the vehicle or alone group. Furthermore, JC-1 staining showed that mitochondrial membrane potential significantly declined in the Ciprofloxacin and AngII combination group compared to others. Compared to the other three groups, pretreatment of Ciprofloxacin plus AngII could further induce mitochondrial fission, demonstrated by mitoTracker staining and western blotting assay. Mechanistically, we found that Ciprofloxacin impaired the balance of mitochondrial fission and fusion dynamics in VSMCs by suppressing the phosphorylation of AMPK signaling. This caused mitochondrial dysfunction and ROS generation, thereby elevating AngII-induced cellular senescence. However, treatment with the AMPK activator partially alleviated those effects. Our data indicate that Ciprofloxacin may accelerate AngII-induced VSMC senescence through modulating AMPK/ROS signaling and, subsequently, hasten the progression of AAD.

Tert promotes cardiac regenerative repair after MI through alleviating ROS-induced DNA damage response in cardiomyocyte

Telomerase reverse transcriptase (Tert) has been found to have a protective effect on telomeric DNA, but whether it could improve the repair of reactive oxygen species (ROS)-induced DNA damage and promote myocardial regenerative repair after myocardial infarction (MI) by protecting telomeric DNA is unclear. The immunofluorescence staining with TEL-CY3 and the TeloTAGGG Telomerase PCR ELISA kit were used to show the telomere length and telomerase activity. The heart-specific Tert-deletion homozygotes were generated by using commercial Cre tool mice and flox heterozygous mice for mating. We measured the telomere length and telomerase activity of mouse cardiomyocytes (CMs) at different days of age, and the results showed that they were negatively correlated with age. Overexpressed Tert could enhance telomerase activity and lengthen telomeres, thereby repairing the DNA damage induced by ROS and promoting CM proliferation in vitro. The in vivo results indicated that enhanced Tert could significantly improve cardiac function and prognosis by alleviating CM DNA damage and promoting angiogenesis post-MI. In terms of mechanism, DNA pulldown assay was used to identify that nuclear ribonucleoprotein A2B1 (hnRNPA2B1) could be an upstream regulator of Tert in CMs. Overexpressed Tert could activate the NF-κB signaling pathway in CMs and bind to the VEGF promoter in the endothelium to increase the VEGF level. Further immunoblotting showed that Tert protected DNA from ROS-induced damage by inhibiting ATM phosphorylation and blocking the Chk1/p53/p21 pathway activation. HnRNPA2B1-activated Tert could repair the ROS-induced telomeric DNA damage to induce the cell cycle re-entry in CMs and enhance the interaction between CMs and endothelium, thus achieving cardiac regenerative repair after MI.

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.

Maternal peripheral blood telomere length and preterm birth in African American women: a pilot study

PURPOSE

This study aimed to explore the association between preterm birth and telomere length of maternal peripheral blood in African American women.

METHODS

78 African American women were recruited for this study between 2018 and 2023 from 2 prenatal clinics in central and east Texas. Participants provided blood samples and completed clinic questionnaires, with clinical data collected from their post-delivery medical records. Telomere length was measured using monochrome multiplex quantitative real-time polymerase chain reaction. Linear regression and multinomial logistic regression were used to analyze the association between telomere length and gestational length. Kruskal-Wallis's test and Fisher's exact test were used to compare preterm birth, early-term birth and full-term birth by telomere length, social-demographic characteristics, stress and discrimination.

RESULTS

The rates of preterm birth was higher in pregnant women with shorter telomeres. After adjusting for confounders, for every 10-units increase in the relative telomere-to-single-copy gene (T/S) ratio, gestational days increased by 1.090 days (90% CI 0.182, 1.997), and for every 10-units decrease in the T/S ratio, the odds of preterm birth was 2.664 (90% CI 1.064, 6.673) times greater than the odds of full-term birth. No statistically significant associations were observed between stress, discrimination, and either preterm birth or telomere length.

CONCLUSIONS

Maternal peripheral blood telomere shortening is associated with preterm birth, providing support to further explore the clinical utility of maternal telomere testing for prediction and early intervention of preterm birth and the study of biological mechanisms of spontaneous preterm birth.

Longer ICU stay and invasive mechanical ventilation accelerate telomere shortening in COVID-19 patients 1 year after recovery

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes virus-induced-senescence. There is an association between shorter telomere length (TL) in coronavirus disease 2019 (COVID-19) patients and hospitalization, severity, or even death. However, it remains unknown whether virus-induced-senescence is reversible. We aim to evaluate the dynamics of TL in COVID-19 patients 1 year after recovery from intensive care units (ICU). Longitudinal study enrolling 49 patients admitted to ICU due to COVID-19 (August 2020 to April 2021). Relative telomere length (RTL) quantification was carried out in whole blood by monochromatic multiplex real-time quantitative PCR (MMqPCR) assay at hospitalization (baseline) and 1 year after discharge (1-year visit). The association between RTL and ICU length of stay (LOS), invasive mechanical ventilation (IMV), prone position, and pulmonary fibrosis development at 1-year visit was evaluated. The median age was 60 years, 71.4% were males, median ICU-LOS was 12 days, 73.5% required IMV, and 38.8% required a prone position. Patients with longer ICU-LOS or who required IMV showed greater RTL shortening during follow-up. Patients who required pronation had a greater RTL shortening during follow-up. IMV patients who developed pulmonary fibrosis showed greater RTL reduction and shorter RTL at the 1-year visit. Patients with longer ICU-LOS and those who required IMV had a shorter RTL in peripheral blood, as observed 1 year after hospital discharge. Additionally, patients who required IMV and developed pulmonary fibrosis had greater telomere shortening, showing shorter telomeres at the 1-year visit. These patients may be more prone to develop cellular senescence and lung-related complications; therefore, closer monitoring may be needed.

Anti-Aging Effects of Flavonoids from Plant Extracts

Aging is a natural and irreversible process, affecting living organisms by negatively impacting the tissues' and cells' morphology and functionality and consequently being responsible for aging-related diseases. Taking into account the actual preoccupations of both consumers and researchers, healthy anti-aging alternatives are being intensively studied in order to address such concerns. Due to their functional features, plant flavonoids can be considered valuable nutraceuticals. This paper highlights the possibilities to use flavonoids extracted from various plants for their anti-aging potential on the skin, brain, and heart. Moreover, their anticarcinogenic, anti-inflammatory, and anti-diabetic properties are summarized, along with the senescence-associated mechanisms. Both the nutraceutical and cosmeceutical fields are continuously developing and flavonoids originating from plants are promising candidates to obtain such products. Thus, the bioactive compounds' extraction and their subsequent involvement in innovative product manufacturing must be carefully performed while being aware of the various intrinsic and extrinsic factors that may affect the phytochemicals' structures, bioavailability, and health effects.

Differential effects of long- and short-term exposure to PM2.5 on accelerating telomere shortening: from in vitro to epidemiological studies

Exposure to air pollutants has been associated with DNA damage and increases the risks of respiratory diseases, such as asthma and COPD; however short- and long-term effects of air pollutants on telomere dysfunction remain unclear. We investigated the impact of short- and long-term exposure to fine particulate matter with an aerodynamic diameter below 2.5 μm (PM2.5) on telomere length in human bronchial epithelial BEAS-2B cells, and assessed the potential correlation between PM2.5 exposure and telomere length in the LIGHTS childhood cohort study. We observed that long-term, but not short-term, PM2.5 exposure was significantly associated with telomere shortening, along with the downregulation of human telomerase reverse transcriptase (hTERT) mRNA and protein levels. Moreover, long-term exposure to PM2.5 induced proinflammatory cytokine secretion, notably interleukin 6 (IL-6) and IL-8, triggered subG1 cell cycle arrest, and ultimately caused cell death. Long-term exposure to PM2.5 upregulated the LC3-II/ LC3-I ratio but led to p62 protein accumulation in BEAS-2B cells, suggesting a blockade of autophagic flux. Moreover, consistent with our in vitro findings, our epidemiological study found significant association between annual average exposure to higher PM2.5 and shortening of leukocyte telomere length in children. However, no significant association between 7-day short-term exposure to PM2.5 and leukocyte telomere length was observed in children. By combining in vitro experimental and epidemiological studies, our findings provide supportive evidence linking potential regulatory mechanisms to population level with respect to long-term PM2.5 exposure to telomere shortening in humans.

Detailing the biomedical aspects of geroscience by molecular data and large-scale "deep" bioinformatics analyses

As scientists investigated the molecular mechanisms of the biology of aging, they discovered that these are malleable and can enhance healthy longevity by intervening in the drivers of aging, which are leading to disease, dysfunction and death. These exciting observations gave birth to the field of geroscience. As the mechanisms of aging affect almost all mechanisms of life, detailed molecular mechanistic knowledge must be gained or expanded by considering and integrating as many types of data as possible, from genes and transcripts to socioenvironmental factors. Such a large-scale integration of large amounts of data will in turn profit from "deep" bioinformatics analyses that provide insights beyond contextualizing and interpreting the data in the light of knowledge from databases such as the Gene Ontology. The authors suggest that "deep" bioinformatics, employing methods based on artificial intelligence, will be a key ingredient of future analyses.

Enhanced recognition of G-quadruplex DNA oxidative damage based on DNA-mediated charge transfer

G-quadruplex (G4) DNA is present in human telomere oligonucleotide sequences. Oxidative damage to telomeric DNA accelerates telomere shortening, which is strongly associated with aging and cancer. Most of the current analyses on oxidative DNA damage are based on ds-DNA. Here, we developed a electrochemiluminescence (ECL) probe for enhanced recognition of oxidative damage in G4-DNA based on DNA-mediated charge transfer (CT), which could specifically recognize damaged sites depending on the position of 8-oxoguanine (8-oxoG). First, a uniform G4-DNA monolayer interface was fabricated; the G4-DNA mediated CT properties were examined using an iridium(III) complex [Ir(ppy)2(pip)]PF6 stacked with G4-DNA as an indicator. The results showed that G4-DNA with 8-oxoG attenuated DNA CT. The topological effects of oxidative damage at different sites of G4-DNA and their effects on DNA CT were revealed. The sensing platform was also used for the sensitive and quantitative detection of 8-oxoG in G4-DNA, with a detection limit of 28.9 fmol. Overall, these findings present a sensitive platform to study G4-DNA structural and stability changes caused by oxidative damage as well as the specific and quantitative detection of oxidation sites. The different damage sites in the G-quadruplex could provide detailed clues for understanding the function of G4-associated telomere functional enzymes.

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.

Telomere Dynamics in Sickle Cell Anemia: Unraveling Molecular Aging and Disease Progression

Sickle Cell Anemia (SCA) is a hereditary blood disorder characterized by the presence of abnormal hemoglobin, leading to the formation of sickle-shaped red blood cells. While extensive research has unraveled many aspects of the genetic and molecular basis of SCA, the role of telomere dynamics in disease progression remains a relatively unexplored frontier. This review seeks to provide a comprehensive examination of telomere biology within the context of SCA, aiming to elucidate its potential impact on molecular aging and the progression of the disease. The impact of oxidative stress on telomere dynamics in SCA is explored, with a particular focus on how increased reactive oxygen species (ROS) may contribute to accelerated telomere shortening and genomic instability. Furthermore, the potential relationship between telomere dysfunction and cellular senescence in SCA is investigated, shedding light on how telomere dynamics may contribute to the premature aging of cells in this population. The review concludes by summarizing key findings and proposing potential therapeutic strategies targeting telomere dynamics to mitigate disease progression in SCA. It also identifies gaps in current understanding and suggests avenues for future research, emphasizing the importance of further investigating telomere biology to advance our understanding of molecular aging and disease progression in Sickle Cell Anemia. This comprehensive exploration of telomere dynamics in SCA offers insights into potential mechanisms of molecular aging and disease progression, paving the way for targeted therapeutic interventions and improved disease management.

Association between osteoporosis and the rate of telomere shortening

A shorter leukocyte telomere length (LTL) is reported to be associated with age-related diseases, including osteoporosis. Many studies have tried identifying the association between LTL and osteoporosis, although it remains controversial. This study aimed to determine whether osteoporosis is independently associated with LTL shortening in a prospective longitudinal cohort. The KBASE study is an independent multicenter prospective cohort in South Korea, which began in 2014. We compared the LTL values for each participant at baseline and over a 2-year follow-up period. Boxplots were used to demonstrate the differences in the change in LTL over a 2-year follow-up according to osteoporosis. Multivariable linear regression was conducted to identify whether osteoporosis is independently associated with the rate of telomere shortening. A total of 233 subjects (from 55 to 88 years) from the KBASE cohort were finally enrolled in the study. We observed that the LTL decreased by approximately 1.2 kbp over 2 years. While the LTL decreased as age increased, the rate of LTL shortening did not increase with age. Multivariable linear regression analysis indicated that only osteoporosis was independently associated with rapid LTL shortening over 2 years (B, -8.08; p = 0.038). We sought to identify an association between osteoporosis and LTL shortening in an independent prospective cohort. We found that participants with osteoporosis had significantly faster LTL shortening over 2 years than those without osteoporosis. We hope this study will help elucidate the underlying mechanisms in the relationship between LTL and osteoporosis in the future.

Revealing the Hidden Impacts: Insights into Biological Aging and Long-Term Effects in Pauci- and Asymptomatic COVID-19 Healthcare Workers

This study explores the role of inflammation and oxidative stress, hallmarks of COVID-19, in accelerating cellular biological aging. We investigated early molecular markers-DNA methylation age (DNAmAge) and telomere length (TL)-in blood leukocytes, nasal cells (NCs), and induced sputum (IS) one year post-infection in pauci- and asymptomatic healthcare workers (HCWs) infected during the first pandemic wave (February-May 2020), compared to COPD patients, model for "aged lung". Data from questionnaires, Work Ability Index (WAI), blood analyses, autonomic cardiac balance assessments, heart rate variability (HRV), and pulmonary function tests were collected. Elevated leukocyte DNAmAge significantly correlated with advancing age, male sex, daytime work, and an aged phenotype characterized by chronic diseases, elevated LDL and glycemia levels, medications affecting HRV, and declines in lung function, WAI, lymphocyte count, hemoglobin levels, and HRV (p < 0.05). Increasing age, LDL levels, job positions involving intensive patient contact, and higher leukocyte counts collectively contributed to shortened leukocyte TL (p < 0.05). Notably, HCWs exhibited accelerated biological aging in IS cells compared to both blood leukocytes (p ≤ 0.05) and NCs (p < 0.001) and were biologically older than COPD patients (p < 0.05). These findings suggest the need to monitor aging in pauci- and asymptomatic COVID-19 survivors, who represent the majority of the general population.

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.

Associations of oxidative balance score with hyperuricemia and gout among American adults: a population-based study

Objective

The current study aimed to assess the relationships between oxidative balance score (OBS) and OBS subclasses (dietary and lifestyle OBS) with risks of hyperuricemia (HUA) and gout among American adults.

Methods

Participants in the National Health and Nutrition Examination Survey from 2007 to 2018 were initially recruited and then the final sample was restricted to adults without missing values about serum uric acid, gout, OBS, and covariates. Rao-Scott adjusted chi-square test and analysis of variance were utilized to compare the baseline characteristics in adults of different quartiles of OBS, while the weighted stepped logistic regression models were used to explore the associations of overall, dietary, and lifestyle OBS with the risks of HUA and gout. Weighted restricted cubic spline analyses were conducted to explore the nonlinear dose-response associations.

Results

The final sample consisted of 22,705 participants aged 20 years and older, which was representative of approximately 197.3 million non-institutionalized American adults. HUA and gout prevalence decreased with OBS quartiles. Compared with adults in the first quartile of OBS, those in the second (OR: 0.85, 95% CI: 0.72-0.99), third (OR: 0.71, 95% CI: 0.58-0.85), and fourth (OR: 0.48, 95% CI: 0.38-0.61) quartiles of OBS had reduced risks of hyperuricemia. Similarly, adults in the second (OR: 0.70, 95% CI: 0.51-0.97) quartile of OBS was associated with lower gout risk in comparison to adults in the lowest quartile. Regarding OBS subclasses, dietary and lifestyle OBS were both negatively correlated with the risk of HUA, and only higher lifestyle OBS was significantly associated with lower gout risk. Furthermore, the subgroup analyses and interaction effects also substantiated similar effects. Significant nonlinear dose-response relationships were observed between overall, dietary, and lifestyle OBS with HUA risk as well as that of lifestyle OBS with gout risk.

Conclusion

This study strongly suggests the significant negative associations of OBS with HUA and gout in American adults and provides a dietary and lifestyle guideline to reduce the risks.

Mendelian randomization evidence based on European ancestry for the causal effects of leukocyte telomere length on prostate cancer

BACKGROUND

Several lines of evidence suggest that leukocyte telomere length (LTL) can affect the development of prostate cancer (PC).

METHODS

Here, we employed single nucleoside polymorphisms (SNPs) as instrumental variables (IVs) for LTL (n = 472,174) and conducted Mendelian randomization analysis to estimate their causal impact on PCs (79,148 patients/61,106 controls and 6311 patients/88,902 controls).

RESULTS

Every 1-s.d extension of LTL increased the risk of PCs by 34%. Additionally, the analysis of candidate mediators between LTL and PCs via two-step Mendelian randomization revealed that among the 23 candidates, Alzheimer's disease, liver iron content, sex hormone binding global levels, naive CD4-CD8-T cell% T cell, and circulating leptin levels played substantial mediating roles. There is no robust evidence to support the reverse causal relationship between LTL and the selected mediators of PCs. Adjusting for the former four mediators, rather than adjusting for circulating leptin levels, decreased the impact of LTL on PCs.

CONCLUSION

This study provides potential intervention measures for preventing LTL-induced PCs.

Can telomeric changes orchestrate the development of autoinflammatory skin diseases?

Telomeres, the safeguarding caps at the tips of chromosomes, are pivotal in the aging process of cells and have been linked to skin ailments and inflammatory conditions. Telomeres undergo a gradual reduction in length and factors such as oxidative stress hasten this diminishing process. Skin diseases including inflammatory conditions can be correlated with the shortening of telomeres and the persistent activation of DNA damage response in skin tissues. Telomere dysfunction could disrupt the balance of the skin, impairs wound healing, and may contribute to abnormal cytokine production. Skin aging and processes related to telomeres may function as one of the triggers for skin diseases. The presence of proinflammatory cytokines and dysfunctional telomeres in conditions such as Dyskeratosis Congenita implies a possible connection between the shortening of telomeres and the onset of chronic inflammatory skin disorders. In autoinflammatory skin diseases, chronic inflammation hinders wound healing thus aggravating the progression of the disease. The NF-ĸB pathway might contribute to the initiation or progression of chronic disorders by influencing mechanisms associated with telomere biology. The intricate connections between telomeres, telomerase, telomere-associated proteins, and skin diseases are still a complex puzzle to be solved. Here, we provide an overview of the impact of telomeres on both health and disease with a specific emphasis on their role in skin, inflammation and autoinflammatory skin disorders.

Leukocyte telomere length is associated with MRI-thigh fat-free muscle volume: data from 16 356 UK Biobank adults

BACKGROUND

Telomere attrition may share common biological mechanisms with bone and muscle loss with aging. Here, we investigated the association between these hallmarks of aging using data from UK Biobank, a large observational study.

METHODS

Leukocyte telomere length (LTL as T/S ratio) was measured using a multiplex qPCR assay at baseline (2006-2010). Bone mineral density (whole body and regional; via dual-energy X-ray absorptiometry), trabecular bone score (via lumbar-spine dual-energy X-ray absorptiometry images), fat-free muscle volume (thighs; via magnetic resonance imaging), and muscle fat infiltration (thighs; via magnetic resonance imaging) were measured during the imaging visit (2014-2018). Regression models were used to model LTL against a muscle or bone outcome, unadjusted and adjusted for covariates.

RESULTS

A total of 16 356 adults (mean age: 62.8 ± 7.5 years, 50.5% women) were included. In the fully adjusted model, thigh fat-free muscle volume was associated with LTL in the overall sample (adjusted standardized β (aβ) = 0.017, 95% CI 0.009 to 0.026, P < 0.001, per SD increase in LTL), with stronger associations in men (aβ = 0.022, 95% CI 0.010 to 0.034, P < 0.001) than in women (aβ = 0.013, 95% CI 0.000 to 0.025, P = 0.041) (sex-LTL P = 0.028). The adjusted odds ratio (aOR) for low thigh fat-free muscle volume (body mass index-adjusted, sex-specific bottom 20%) was 0.93 per SD increase in LTL (95% CI 0.89 to 0.96, P < 0.001) in the overall sample, with stronger associations in men (aOR = 0.92, 95% CI 0.87 to 0.99, P = 0.008) than women (aOR = 0.93, 95% CI 0.88 to 0.98, P = 0.009), although the sex difference was not statistically significant in this model (sex-LTL P = 0.37). LTL was not associated with bone mineral density, trabecular bone score, or muscle fat infiltration in the overall or subgroup analyses (P > 0.05).

CONCLUSIONS

LTL was consistently associated with thigh fat-free muscle volume in men and women. Future research should investigate moderating effects of lifestyle factors (e.g., physical activity, nutrition, or chronic diseases) in the association between LTL and muscle volume.

Parental Preconception Posttraumatic Stress Symptoms and Maternal Prenatal Inflammation Prospectively Predict Shorter Telomere Length in Children

OBJECTIVE

Parental trauma exposure and trauma-related distress can increase the risk of adverse health outcomes in offspring, but the pathways implicated in intergenerational transmission are not fully explicated. Accelerated biological aging may be one mechanism underlying less favorable health in trauma-exposed individuals and their offspring. This study examines the associations of preconception maternal and paternal posttraumatic stress disorder (PTSD) symptoms with child telomere length, and maternal prenatal C-reactive protein (CRP) as a biological mechanism.

METHODS

Mothers ( n = 127) and a subset of the fathers ( n = 84) reported on PTSD symptoms before conception. Mothers provided blood spots in the second and third trimesters that were assayed for CRP. At age 4 years, children provided buccal cells for measurement of telomere length. Models adjusted for parental age, socioeconomic status, maternal prepregnancy body mass index, child biological sex, and child age.

RESULTS

Mothers' PTSD symptoms were significantly associated with shorter child telomere length ( β = -0.22, SE = 0.10, p = .023). Fathers' PTSD symptoms were also inversely associated with child telomere length ( β = -0.21, SE = 0.11), although nonsignificant ( p = .065). There was no significant indirect effect of mothers' PTSD symptoms on child telomere length through CRP in pregnancy, but higher second-trimester CRP was significantly associated with shorter child telomere length ( β = -0.35, SE = 0.18, p = .048).

CONCLUSIONS

Maternal symptoms of PTSD before conception and second-trimester inflammation were associated with shorter telomere length in offspring in early childhood, independent of covariates. Findings indicate that intergenerational transmission of parental trauma may occur in part through accelerated biological aging processes and provide further evidence that prenatal proinflammatory processes program child telomere length.Open Science Framework Preregistration:https://osf.io/7c2d5/?view_only=cd0fb81f48db4b8f9c59fc8bb7b0ef97 .

Association between maternal depression symptoms and child telomere length

The biological mechanisms that explain how adverse early life events influence adult disease risk are poorly understood. One proposed mechanism is via the induction of accelerated biological aging, for which telomere length is considered a biomarker. We aimed to determine if maternal depression pre- and post-partum was associated with telomere length in children at 4 years of age (n = 4299). Mothers completed structured questionnaires assessing depression during pregnancy (Edinburgh Depression Scale), at 9 months (Edinburgh Depression Scale), and at 54 months postpartum (Patient Health Questionnaire 9). Regression methods were used to investigate the relationship between telomere length (DNA from saliva) and maternal depression score recorded at each stage. Significant covariates included in the final model were: maternal age at pregnancy; child sex; child ethnicity; gestational age group, and rurality group. Child telomere length was found to be longer if their mother had a higher depression score at both postpartum time points tested (9 months of age; coefficient 0.003, SE = 0.001, P = 0.01, 54 months of age; coefficient 0.003, SE = 0.002, P = 0.02). Although these findings seem paradoxical, increased telomere length may be an adaptive response to early life stressors. We propose several testable hypotheses for these results and to determine if the positive association between depression and telomere length is a developmental adaptation or an indirect consequence of environmental factors.

What improvements do general exercise training and traditional Chinese exercises have on knee osteoarthritis? A narrative review based on biological mechanisms and clinical efficacy

Background

Knee osteoarthritis (KOA) is a disease that significantly affects the quality of life of patients, with a complex pathophysiology that includes degeneration of cartilage and subchondral bone, synovitis, and associations with mechanical load, inflammation, metabolic factors, hormonal changes, and aging.

Objective

This article aims to comprehensively review the biological mechanisms and clinical effects of general exercise training and traditional Chinese exercises (such as Tai Chi and Qigong) on the treatment of KOA, providing references for the development of clinical exercise prescriptions.

Methods

A systematic search of databases including PubMed, Web of Science, Google Scholar, and China National Knowledge Infrastructure (CNKI) was conducted, reviewing studies including randomized controlled trials (RCTs), observational studies, systematic reviews, and meta-analyses. Keywords included "knee osteoarthritis," "exercise therapy," "physical activity," and "traditional Chinese exercise."

Results and conclusion

General exercise training positively affects KOA by mechanisms such as promoting blood circulation, improving the metabolism of inflammatory factors, enhancing the expression of anti-inflammatory cytokines, and reducing cartilage cell aging. Traditional Chinese exercises, like Tai Chi and Qigong, benefit the improvement of KOA symptoms and tissue repair by regulating immune function and alleviating joint inflammation. Clinical studies have shown that both types of exercise can improve physical function, quality of life, and pain relief in patients with KOA. Both general exercise training and traditional Chinese exercises are non-pharmacological treatment options for KOA that can effectively improve patients' physiological function and quality of life. Future research should further explore the long-term effects and biological mechanisms of these exercise interventions and develop personalized exercise programs based on the specific needs of patients.

Role of Mesenchymal Stem/Stromal Cells (MSCs) and MSC-Derived Extracellular Vesicles (EVs) in Prevention of Telomere Length Shortening, Cellular Senescence, and Accelerated Biological Aging

Biological aging is defined as a progressive decline in tissue function that eventually results in cell death. Accelerated biologic aging results when the telomere length is shortened prematurely secondary to damage from biological or environmental stressors, leading to a defective reparative mechanism. Stem cells therapy may have a potential role in influencing (counteract/ameliorate) biological aging and maintaining the function of the organism. Mesenchymal stem cells, also called mesenchymal stromal cells (MSCs) are multipotent stem cells of mesodermal origin that can differentiate into other types of cells, such as adipocytes, chondrocytes, and osteocytes. MSCs influence resident cells through the secretion of paracrine bioactive components such as cytokines and extracellular vesicles (EVs). This review examines the changes in telomere length, cellular senescence, and normal biological age, as well as the factors contributing to telomere shortening and accelerated biological aging. The role of MSCs-especially those derived from gestational tissues-in prevention of telomere shortening (TS) and accelerated biological aging is explored. In addition, the strategies to prevent MSC senescence and improve the antiaging therapeutic application of MSCs and MSC-derived EVs in influencing telomere length and cellular senescence are reviewed.

The influence of perceived stress and motivation on telomere length among NCAA swimmers

INTRODUCTION

Telomere length (TL) shortening is associated with increased cellular senescence and functional decline with age. Regular physical activity is posited to safeguard against TL shortening, but there is disagreement on how concurrent psychosocial stress may influence this relationship. The current analysis explored whether psychosocial stress is associated with TL differences in highly physically active individuals.

METHODS

TL was measured from capillary dried blood spots collected from Division-I (D-1) and Division-III (D-3) National Collegiate Athletics Association (NCAA) swimmers (N = 28) and non-athlete students from the same schools (N = 15). All participants completed Cohen's Perceived Stress Scale (PSS) and student-athletes completed an additional questionnaire to assess psychosocial factors associated with their lifestyle; The Student Athletes' Motivation towards Sports and Academics Questionnaire (SAMSAQ). Semi-structured interviews further contextualized how student-athletes internalize their stress.

RESULTS

There was no significant difference in TL or PSS scores between swimmers and controls. D-1 swimmers reported significantly higher career and student-athlete motivation scores compared to D-3, but non-significantly higher PSS and similar academic motivation scores. Themes from interviews with collegiate swimmers included COVID-19 stress, fear of injury, pressure from academics, expectations to perform, and financial pressures.

CONCLUSIONS

These themes may have contributed to higher PSS scores in D-1 swimmers compared to D-3 but did not appear to impact their TL. Given differences in perceived stress, sources of stress, and SAMSAQ scores, further analyses with larger sample sizes are needed to better understand how these factors influence human biology and health while engaged in intense physical activity.

Hydroxytyrosol ameliorates stress-induced liver injury through activating autophagy via HDAC1/2 inhibition

Hydroxytyrosol (HT), a phenolic extra-virgin olive oil compound used as a food supplement, has been recognized to protect liver function and alleviate stress-induced depressive-like behaviors. However, its protective effects against stress-induced liver injury (SLI) remain unknown. Here, the anti-SLI effect of HT was evaluated in mice with chronic unpredictable mild stress-induced SLI. Network pharmacology combined with molecular docking was used to clarify the underlying mechanism of action of HT against SLI, followed by experimental verification. The results showed that accompanying with the alleviation of HT on stress-induced depressive-like behaviors, HT was confirmed to exert the protective effects against SLI, as represented by reduced serum corticosterone (CORT), aspartate aminotransferase and alanine aminotransferase activities, as well as repair of liver structure, inhibition of oxidative homeostasis collapse, and inflammation reaction in the liver. Furthermore, core genes including histone deacetylase 1 and 2 (HDAC1/2), were identified as potential targets of HT in SLI based on bioinformatic screening and simulation. Consistently, HT significantly inhibited HDAC1/2 expression to maintain mitochondrial dysfunction in an autophagy-dependent manner, which was confirmed in a CORT-induced AML-12 cell injury and SLI mice models combined with small molecule inhibitors. We provide the first evidence that HT inhibits HDAC1/2 to induce autophagy in hepatocytes for maintaining mitochondrial dysfunction, thus preventing inflammation and oxidative stress for exerting an anti-SLI effect. This constitutes a novel therapeutic modality to synchronously prevent stress-induced depression-like behaviors and liver injury, supporting the advantaged therapeutic potential of HT.

Biomarkers of Aging and Relevant Evaluation Techniques: A Comprehensive Review

The risk of developing chronic illnesses and disabilities is increasing with age. To predict and prevent aging, biomarkers relevant to the aging process must be identified. This paper reviews the known molecular, cellular, and physiological biomarkers of aging. Moreover, we discuss the currently available technologies for identifying these biomarkers, and their applications and potential in aging research. We hope that this review will stimulate further research and innovation in this emerging and fast-growing field.

Investigating the Relationship between Telomere-Related Gene Variants and Leukocyte Telomere Length in Optic Neuritis Patients

Optic neuritis (ON) is a condition marked by optic nerve inflammation due to various potential triggers. Research indicates a link between telomeres and inflammation, as studies demonstrate that inflammation can lead to increased telomere shortening. Aim: We aimed to determine the associations of telomere-related telomeric repeat binding factor 1 (TERF1) rs1545827, rs10107605, and telomeric repeat binding factor 2 (TERF2) rs251796 polymorphisms and relative leukocyte telomere length (LTL) with the occurrence of ON. Methods: In this research, a total of 73 individuals diagnosed with optic neuritis (ON) were studied and the control group included 170 individuals without any health issues. The DNA samples were obtained from peripheral blood leukocytes, which were purified using the DNA salting-out technique. Real-time polymerase chain reaction (RT-PCR) assessed single-nucleotide polymorphisms (SNPs) and relative leukocyte telomere lengths (LTL). The data obtained were processed and analyzed using the "IBM SPSS Statistics 29.0" program. Results: Our study revealed the following results: in the male group, TERF2 rs251796 (AA, AG, and TT) statistically significantly differed between the long and short telomere group, with frequencies of 65.7%, 22.9%, and 2.0% in long telomeres, compared to 35.1%, 56.8%, and 8.1% in the short telomere group (p = 0.013). The TERF2 rs251796 CT genotype, compared to CC, under the codominant genetic model, was associated with 4.7-fold decreased odds of telomere shortening (p = 0.005). Meanwhile, CT+TT genotypes, compared to CC under the dominant genetic model, were associated with 3.5-fold decreased odds of telomere shortening (p = 0.011). Also, the CT genotype, compared to CC+TT, under the overdominant genetic model, was associated with 4.4-fold decreased odds of telomere shortening (p = 0.004). Conclusions: The current evidence may suggest a protective role of TERF2 rs251796 in the occurrence of ON in men.

The Effects of Exercise on Telomere Length in Persons With Heart Failure

BACKGROUND

Telomere length is reduced in persons with heart failure (HF). Inflammation is a putative mechanism contributing to telomere shortening. Although physical activity is known to increase telomere length, its effects in HF are unknown.

OBJECTIVE

The aim of this study was to examine the effects of exercise on telomere length and its relationship with interleukin (IL)-1β in persons with HF.

METHODS

This secondary analysis of a 3-month home-based aerobic exercise intervention measured total telomere length and IL-1β levels in persons with HF (69% with reduced ejection fraction).

RESULTS

Total telomere length increased and plasma IL-1β levels decreased in the exercise group from baseline to 3 months. Total telomere length was negatively associated with IL-1β at baseline ( r = -0.441 P = .001).

CONCLUSIONS

The association between telomere length and IL-1β suggests a relationship between inflammation and cellular aging. Moderate-intensity exercise may help maintain cellular functions. Further research is needed to examine the effects on outcomes in persons with HF.

Mitochondrial dysfunction in chronic neuroinflammatory diseases (Review)

Chronic neuroinflammation serves a key role in the onset and progression of neurodegenerative disorders. Mitochondria serve as central regulators of neuroinflammation. In addition to providing energy to cells, mitochondria also participate in the immunoinflammatory response of neurodegenerative disorders including Alzheimer's disease, Parkinson's disease, multiple sclerosis and epilepsy, by regulating processes such as cell death and inflammasome activation. Under inflammatory conditions, mitochondrial oxidative stress, epigenetics, mitochondrial dynamics and calcium homeostasis imbalance may serve as underlying regulatory mechanisms for these diseases. Therefore, investigating mechanisms related to mitochondrial dysfunction may result in therapeutic strategies against chronic neuroinflammation and neurodegeneration. The present review summarizes the mechanisms of mitochondria in chronic neuroinflammatory diseases and the current treatment approaches that target mitochondrial dysfunction in these diseases.

New insights from bidirectional Mendelian randomization: causal relationships between telomere length and mitochondrial DNA copy number in aging biomarkers

Mitochondrial DNA (mtDNA) copy number and telomere length (TL) are dynamic factors that have been linked to the aging process in organisms. However, the causal relationship between these variables remains uncertain. In this research, instrumental variables (IVs) related to mtDNA copy number and TL were obtained from publicly available genome-wide association studies (GWAS). Through bidirectional Mendelian randomization (MR) analysis, we examined the potential causal relationship between these factors. The forward analysis, with mtDNA copy number as the exposure and TL as the outcome, did not reveal a significant effect (B=-0.004, P>0.05). On the contrary, upon conducting a reverse analysis, it was found that there exists a positive causal relationship (B=0.054, P<0.05). Sensitivity analyses further confirmed the reliability of these results. The outcomes of this study indicate a one-way positive causal relationship, indicating that telomere shortening in the aging process may lead to a decrease in mtDNA copy number, providing new perspectives on their biological mechanisms.

Mechanisms of mitochondrial dysfunction in ovarian aging and potential interventions

Mitochondria plays an essential role in regulating cellular metabolic homeostasis, proliferation/differentiation, and cell death. Mitochondrial dysfunction is implicated in many age-related pathologies. Evidence supports that the dysfunction of mitochondria and the decline of mitochondrial DNA copy number negatively affect ovarian aging. However, the mechanism of ovarian aging is still unclear. Treatment methods, including antioxidant applications, mitochondrial transplantation, emerging biomaterials, and advanced technologies, are being used to improve mitochondrial function and restore oocyte quality. This article reviews key evidence and research updates on mitochondrial damage in the pathogenesis of ovarian aging, emphasizing that mitochondrial damage may accelerate and lead to cellular senescence and ovarian aging, as well as exploring potential methods for using mitochondrial mechanisms to slow down aging and improve oocyte quality.

Outdoor fine particulate matter exposure and telomere length in humans: A systematic review and meta-analysis

Although the association between changes in human telomere length (TL) and ambient fine particulate matter (PM2.5) has been documented, there remains disagreement among the related literature. Our study conducted a systematic review and meta-analysis of epidemiological studies to investigate the health effects of outdoor PM2.5 exposure on human TL after a thorough database search. To quantify the overall effect estimates of TL changes associated with every 10 μg/m3 increase in PM2.5 exposure, we focused on two main topics, which were outdoor long-term exposure and prenatal exposure of PM2.5. Additionally, we included a summary of short-term PM2.5 exposure and its impact on TL due to limited data availability. Our qualitative analysis included 20 studies with 483,600 participants. The meta-analysis showed a statistically significant association between outdoor PM2.5 exposure and shorter human TL, with pooled impact estimates (β) of -0.12 (95% CI: -0.20, -0.03, I2= 95.4%) for general long-term exposure and -0.07 (95% CI: -0.15, 0.00, I2= 74.3%) for prenatal exposure. In conclusion, our findings suggest that outdoor PM2.5 exposure may contribute to TL shortening, and noteworthy associations were observed in specific subgroups, suggesting the impact of various research variables. Larger, high-quality studies using standardized methodologies are necessary to strengthen these conclusions further.

Telomeres and telomerase: active but complex players in life-history decisions

Studies on human telomeres have established that telomeres exert a significant influence on lifespan and health of organisms. However, recent research has indicated that the original idea that telomeres affect lifespan in a universal and central manner across all eukaryotic species is an oversimplification. Indeed, findings from a variety of animal species revealed that the role of telomere biology in aging is more subtle and intricate than previously recognized. Here, we show how telomere biology varies depending on the taxon. We also show how telomere biology corresponds to basic life history traits and affects the life table of a species and investments in growth, body size, reproduction, and lifespan; telomeres are hypothesized to shape evolutionary perspectives for species in an active but complex manner. Our evaluation is based on telomere biology data from many examples from throughout the animal kingdom that vary according to the degree of organismal complexity and life history strategies.

Establishment of immortalized Egyptian Rousettus bat cell lines

The Egyptian Rousettus bat (Rousettus aegyptiacus) is a common fruit bat species that is distributed mainly in Africa and the Middle East. Bats serve as reservoir hosts for numerous pathogens. Human activities, such as hunting bats for food, managing vermin, and causing habitat loss, elevate the likelihood of transmission of bat pathogens to humans and other animals. Consequently, bat cell lines play a crucial role as research materials for investigating viral pathogens. However, the inherent limitation of finite cell division in primary cells necessitates the use of immortalized cells derived from various bat tissues. Herein, we successfully established six fibroblast cell lines derived from an infant bat heart and lungs and an elderly bat heart. Three of the six cell lines, called K4DT cells, were transduced by a combination of cell cycle regulators, mutant cyclin-dependent kinase 4, cyclin D1, and human telomerase reverse transcriptase. The other three cell lines, named SV40 cells, were transfected with simian virus 40 large T antigen. Transgene protein expression was detected in the transduced cells. All three K4DT cell lines and one lung-derived SV40 cell line were virtually immortalized and nearly maintained the normal diploid karyotypes. However, the two other heart-derived SV40 cell lines had aberrant karyotypes and the young bat-derived cell line stopped proliferating at approximately 40 population doublings. These bat cell lines are valuable for studying pathogen genomics and biology.

The role of DNA damage in neural stem cells ageing

Neural stem cells (NSCs) are pluripotent stem cells with the potential to differentiate into a variety of nerve cells. NSCs are susceptible to both intracellular and extracellular insults, thus causing DNA damage. Extracellular insults include ultraviolet, ionizing radiation, base analogs, modifiers, alkyl agents and others, while intracellular factors include Reactive oxygen species (ROS) radicals produced by mitochondria, mismatches that occur during DNA replication, deamination of bases, loss of bases, and more. When encountered with DNA damage, cells typically employ three coping strategies: DNA repair, damage tolerance, and apoptosis. NSCs, like many other stem cells, have the ability to divide, differentiate, and repair DNA damage to prevent mutations from being passed down to the next generation. However, when DNA damage accumulates over time, it will lead to a series of alterations in the metabolism of cells, which will cause cellular ageing. The ageing and exhaustion of neural stem cell will have serious effects on the body, such as neurodegenerative diseases. The purpose of this review is to examine the processes by which DNA damage leads to NSCs ageing and the mechanisms of DNA repair in NSCs.

Telomere length and cancer risk: finding Goldilocks

Telomeres are the nucleoprotein complex at chromosome ends essential in genomic stability. Baseline telomere length (TL) is determined by rare and common germline genetic variants but shortens with age and is susceptible to certain environmental exposures. Cellular senescence or apoptosis are normally triggered when telomeres reach a critically short length, but cancer cells overcome these protective mechanisms and continue to divide despite chromosomal instability. Rare germline variants in telomere maintenance genes cause exceedingly short telomeres for age (< 1st percentile) and the telomere biology disorders, which are associated with elevated risks of bone marrow failure, myelodysplastic syndrome, acute myeloid leukemia, and squamous cell carcinoma of the head/neck and anogenital regions. Long telomeres due to rare germline variants in the same or different telomere maintenance genes are associated with elevated risks of other cancers, such as chronic lymphocytic leukemia or sarcoma. Early epidemiology studies of TL in the general population lacked reproducibility but new methods, including creation of a TL polygenic score using common variants, have found longer telomeres associated with excess risks of renal cell carcinoma, glioma, lung cancer, and others. It has become clear that when it comes to TL and cancer etiology, not too short, not too long, but "just right" telomeres are important in minimizing cancer risk.

Influence of breed and environment on leukocyte telomere length in cattle

High milk yield is associated with reduced longevity in high-producing dairy cattle breeds. Pre-term culling leads to high replacement heifer demand and economic losses for the dairy industry. Selection for this trait is limited because of low heritability and difficulties in phenotype measurement. Telomeres are elements found at the ends of chromosomes, consisting of repetitive DNA sequences, several thousand base pairs in length, coupled with nucleoprotein complexes. Eventually, in humans and most other animals, telomere length reduces with age. When telomeric DNA is truncated to a critical length, cell ageing, cell cycle arrest, and apoptosis are induced. As a result, telomere length can be considered as a predictor of health risks and an individual's lifespan. The leukocyte telomere length may be used as a proxy phenotype of productive lifespan to improve cattle selection. Our objectives were to assess the effects of breed and breed group (dairy vs. beef) on the leukocyte telomere length and to estimate the effect of cold climate on this trait in Kalmyk cattle populations from the South (Rostov Oblast) and Far North (Republic of Sakha) regions of Russia. The leukocyte telomere lengths were estimated computationally from whole-genome resequencing data. We leveraged data on leukocyte telomere length, sex, and age of 239 animals from 17 cattle breeds. The breed factor had a significant effect on leukocyte telomere length across our sample. There was no difference in leukocyte telomere length between dairy and beef groups. The population factor had a significant effect on leukocyte telomere length in Kalmyk animals. In conclusion, we found that breed, but not breed group (dairy vs. beef), was significantly associated with leukocyte telomere length in cattle. Residence in colder climates was associated with longer leukocyte telomere length in Kalmyk breed cattle.

The Therapeutic Trip of Melatonin Eye Drops: From the Ocular Surface to the Retina

Melatonin is a ubiquitous molecule found in living organisms, ranging from bacteria to plants and mammals. It possesses various properties, partly due to its robust antioxidant nature and partly owed to its specific interaction with melatonin receptors present in almost all tissues. Melatonin regulates different physiological functions and contributes to the homeostasis of the entire organism. In the human eye, a small amount of melatonin is also present, produced by cells in the anterior segment and the posterior pole, including the retina. In the eye, melatonin may provide antioxidant protection along with regulating physiological functions of ocular tissues, including intraocular pressure (IOP). Therefore, it is conceivable that the exogenous topical administration of sufficiently high amounts of melatonin to the eye could be beneficial in several instances: for the treatment of eye pathologies like glaucoma, due to the IOP-lowering and neuroprotection effects of melatonin; for the prevention of other dysfunctions, such as dry eye and refractive defects (cataract and myopia) mainly due to its antioxidant properties; for diabetic retinopathy due to its metabolic influence and neuroprotective effects; for macular degeneration due to the antioxidant and neuroprotective properties; and for uveitis, mostly owing to anti-inflammatory and immunomodulatory properties. This paper reviews the scientific evidence supporting the use of melatonin in different ocular districts. Moreover, it provides data suggesting that the topical administration of melatonin as eye drops is a real possibility, utilizing nanotechnological formulations that could improve its solubility and permeation through the eye. This way, its distribution and concentration in different ocular tissues may support its pleiotropic therapeutic effects.

Unraveling the causal association between leukocyte telomere length and infertility: A two-sample Mendelian randomization study

Infertility is a significant challenge in modern society, and observed studies have reported the association between telomere length and infertility. Whether this relationship is causal remains controversial.We employed two-sample mendelian randomization (MR) to investigate the causal relationship between leukocyte telomere length (LTL) and major causes of infertility, including male and female infertility, sperm abnormalities, and endometriosis. MR analyses were mainly performed using the inverse variance weighted (IVW) method and complemented with other MR methods.Our findings demonstrate a causal association between LTL and endometriosis (OR1.304, 95% CI (1.122,1.517), p = 0.001), suggesting its potential as a biomarker for this condition. However, we did not observe a significant causal relationship between LTL and other infertility causes.Our study presents compelling evidence on the relationship between LTL and endometriosis. Meanwhile, our study demonstrates that there is no causal relationship between LTL and infertility. This research contributes to the field by shedding light on the importance of LTL in the early diagnosis and intervention of endometriosis.

Mitigating cellular aging and enhancing cognitive functionality: visual arts-mediated Cognitive Activation Therapy in neurocognitive disorders

The growing phenomenon of population aging is redefining demographic dynamics, intensifying age-related conditions, especially dementia, projected to triple by 2050 with an enormous global economic burden. This study investigates visual arts-mediated Cognitive Activation Therapy (CAT) as a non-pharmacological CAT intervention targets both biological aging [leukocyte telomere length (LTL), DNA methylation age (DNAmAge)] and cognitive functionality. Aligning with a broader trend of integrating non-pharmacological approaches into dementia care. The longitudinal study involved 20 patients with mild to moderate neurocognitive disorders. Cognitive and functional assessments, and biological aging markers -i.e., LTL and DNAmAge- were analyzed before and after CAT intervention. Change in LTL was positively correlated with days of treatment (p =0.0518). LTL significantly elongated after intervention (p =0.0269), especially in men (p =0.0142), correlating with younger age (p =0.0357), and higher education (p =0.0008). DNAmAge remained instead stable post-treatment. Cognitive and functional improvements were observed for Copy of complex geometric figure, Progressive Silhouettes, Position Discrimination, Communication Activities of Daily Living-Second edition, Direct Functional Status (p < 0.0001) and Object decision (p =0.0594), but no correlations were found between LTL and cognitive gains. Visual arts-mediated CAT effectively mitigates cellular aging, especially in men, by elongating LTL. These findings underscore the potential of non-pharmacological interventions in enhancing cognitive and functional status and general well-being in dementia care. Further research with larger and longer-term studies is essential for validation.

Correlation of telomere length in brain tissue with peripheral tissues in living human subjects

Telomeres are important to chromosomal stability, and changes in their length correlate with disease, potentially relevant to brain disorders. Assessing telomere length in human brain is invasive, but whether peripheral tissue telomere length correlates with that in brain is not known. Saliva, buccal, blood, and brain samples were collected at time points before, during, and after subjects undergoing neurosurgery (n = 35) for intractable epilepsy. DNA was isolated from samples and average telomere length assessed by qPCR. Correlations of telomere length between tissue samples were calculated across subjects. When data were stratified by sex, saliva telomere length correlated with brain telomere length in males only. Buccal telomere length correlated with brain telomere length when males and females were combined. These findings indicate that in living subjects, telomere length in peripheral tissues variably correlates with that in brain and may be dependent on sex. Peripheral tissue telomere length may provide insight into brain telomere length, relevant to assessment of brain disorder pathophysiology.

Telomere length and TERT polymorphisms as biomarkers in asbestos-related diseases

BACKGROUND

Asbestos exposure has been proposed as a risk factor for shorter telomere length. The aim of our study was to investigate whether telomere length in leukocytes and hTERT genetic polymorphisms may serve as potential biomarkers for the risk of developing asbestos-related diseases and as biomarkers of progression and chemotherapy response rate in malignant mesothelioma (MM).

SUBJECTS AND METHODS

We conducted two retrospective studies. In the first study, a case-control study, telomere length and hTERT polymorphisms were determined in patients with MM, subjects with pleural plaques and controls without the asbestos related disease, who were occupationally exposed to asbestos. In the second study, a longitudinal observational study, telomere length was also determined in samples from MM patients before and after chemotherapy. Telomere length was determined by monochromatic multiplex quantitative polymerase chain reaction (PCR), while competitive allele-specific PCR was used to genotype hTERT rs10069690, rs2736100 and rs2736098. Logistic regression and survival analysis were used in statistical analysis.

RESULTS

Patients with MM had shorter telomere length than subjects with pleural plaques (p < 0.001). After adjustment for age, rs2736098 CT, and rs10069690 TT and CT+TT genotypes were significantly associated with a higher risk of MM (padj = 0.023; padj = 0.026 and padj = 0.017), while rs2736100 AA and CA+AA genotypes conferred to a lower risk for MM compared to all other subjects (padj = 0.017, and padj = 0.026). Telomere length was not associated with a response to chemotherapy (p > 0.05) or time to disease progression (p > 0.05). Carriers of one or two polymorphic rs10069690 T alleles had a good response to chemotherapy (p = 0.039, and p = 0.048), these associations remained statistically significant after adjustment for age (padj = 0.019; padj = 0.017). Carriers of two polymorphic rs2736100 A alleles had a longer time to disease progression (p = 0.038).

CONCLUSIONS

Shorter telomere length and hTERT polymorphisms may serve as a biomarker for the risk of developing MM. Additionally, rs10069690 and rs2736100 polymorphisms, but not telomere length, were associated with a chemotherapy response or MM progression.

Electroacupuncture pretreatment preserves telomerase reverse transcriptase function and alleviates postoperative cognitive dysfunction by suppressing oxidative stress and neuroinflammation in aged mice

BACKGROUND

Elderly patients often exhibit postoperative cognitive dysfunction (POCD), a postsurgical decline in memory and executive function. Oxidative stress and neuroinflammation, both pathological characteristics of the aged brain, contribute to this decline. This study posits that electroacupuncture (EA) stimulation, an effective antioxidant and anti-inflammatory modality, may enhance telomerase reverse transcriptase (TERT) function, the catalytic subunit of telomerase known for its protective properties against cellular senescence and oxidative damage, to alleviate POCD in aged mice.

METHODS

The animal POCD model was created by subjecting aged mice to abdominal surgery, followed by EA pretreatment at the Baihui acupoint (GV20). Postoperative cognitive function was gauged using the Morris water maze (MWM) test. Hippocampal TERT mRNA levels and telomerase activity were determined through qPCR and a Telomerase PCR ELISA kit, respectively. Oxidative stress was assessed through superoxide dismutase (SOD), reactive oxygen species (ROS), and malondialdehyde (MDA) levels. Iba-1 immunostaining determined the quantity of hippocampal microglia. Additionally, western blotting assessed TERT, autophagy markers, and proinflammatory cytokines at the protein level.

RESULTS

Abdominal surgery in aged mice significantly decreased telomerase activity and TERT mRNA and protein levels, but increased oxidative stress and neuroinflammation and decreased autophagy in the hippocampus. EA-pretreated mice demonstrated improved postoperative cognitive performance, enhanced telomerase activity, increased TERT protein expression, improved TERT mitochondrial localization, and reduced oxidative damage, autophagy dysfunction, and neuroinflammation. The neuroprotective benefits of EA pretreatment were diminished following TERT knockdown.

CONCLUSIONS

Our findings underscore the significance of TERT function preservation in alleviating surgery-induced oxidative stress and neuroinflammation in aged mice. A novel neuroprotective mechanism of EA stimulation is highlighted, whereby modulation of TERT and telomerase activity reduces oxidative damage and neuroinflammation. Consequently, maintaining TERT function via EA treatment could serve as an effective strategy for managing POCD in elderly patients.

Cutaneous Redox Senescence

Our current understanding of skin cell senescence involves the role of environmental stressors (UV, O3, cigarette smoke, particulate matter, etc.), lifestyle (diet, exercise, etc.) as well as genetic factors (metabolic changes, hormonal, etc.). The common mechanism of action of these stressors is the disturbance of cellular redox balance characterized by increased free radicals and reactive oxygen species (ROS), and when these overload the intrinsic antioxidant defense system, it can lead to an oxidative stress cellular condition. The main redox mechanisms that activate cellular senescence in the skin involve (1) the oxidative damage of telomeres causing their shortening; (2) the oxidation of proteomes and DNA damage; (3) an a in lysosomal mass through the increased activity of resident enzymes such as senescence-associated β-galactosidase (SA-β-gal) as well as other proteins that are products of lysosomal activity; (4) and the increased expression of SASP, in particular pro-inflammatory cytokines transcriptionally regulated by NF-κB. However, the main targets of ROS on the skin are the proteome (oxi-proteome), followed by telomeres, nucleic acids (DNAs), lipids, proteins, and cytoplasmic organelles. As a result, cell cycle arrest pathways, lipid peroxidation, increased lysosomal content and dysfunctional mitochondria, and SASP synthesis occur. Furthermore, oxidative stress in skin cells increases the activity of p16INK4A and p53 as inhibitors of Rb and CDks, which are important for maintaining the cell cycle. p53 also promotes the inactivation of mTOR-mediated autophagic and apoptotic pathways, leading to senescence. However, these markers alone cannot establish the state of cellular senescence, and multiple analyses are encouraged for confirmation. An updated and more comprehensive approach to investigating skin senescence should include further assays of ox-inflammatory molecular pathways that can consolidate the understanding of cutaneous redox senescence.

The crosstalk between telomeres and DNA repair mechanisms: an overview to mammalian somatic cells, germ cells, and preimplantation embryos

Telomeres are located at the ends of linear chromosomes and play a critical role in maintaining genomic stability by preventing premature activation of DNA repair mechanisms. Because of exposure to various genotoxic agents, telomeres can undergo shortening and genetic changes. In mammalian cells, the basic DNA repair mechanisms, including base excision repair, nucleotide excision repair, double-strand break repair, and mismatch repair, function in repairing potential damages in telomeres. If these damages are not repaired correctly in time, the unfavorable results such as apoptosis, cell cycle arrest, and cancerous transition may occur. During lifespan, mammalian somatic cells, male and female germ cells, and preimplantation embryos experience a number of telomeric damages. Herein, we comprehensively reviewed the crosstalk between telomeres and the DNA repair mechanisms in the somatic cells, germ cells, and embryos. Infertility development resulting from possible defects in this crosstalk is also discussed in the light of existing studies.

Identification of the Maize PP2C Gene Family and Functional Studies on the Role of ZmPP2C15 in Drought Tolerance

The protein phosphatase PP2C plays an important role in plant responses to stress. Therefore, the identification of maize PP2C genes that respond to drought stress is particularly important for the improvement and creation of new drought-resistant assortments of maize. In this study, we identified 102 ZmPP2C genes in maize at the genome-wide level. We analyzed the physicochemical properties of 102 ZmPP2Cs and constructed a phylogenetic tree with Arabidopsis. By analyzing the gene structure, conserved protein motifs, and synteny, the ZmPP2Cs were found to be strongly conserved during evolution. Sixteen core genes involved in drought stress and rewatering were screened using gene co-expression network mapping and expression profiling. The qRT-PCR results showed 16 genes were induced by abscisic acid (ABA), drought, and NaCl treatments. Notably, ZmPP2C15 exhibited a substantial expression difference. Through genetic transformation, we overexpressed ZmPP2C15 and generated the CRISPR/Cas9 knockout maize mutant zmpp2c15. Overexpressing ZmPP2C15 in Arabidopsis under drought stress enhanced growth and survival compared with WT plants. The leaves exhibited heightened superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT) activities, elevated proline (Pro) content, and reduced malondialdehyde (MDA) content. Conversely, zmpp2c15 mutant plants displayed severe leaf dryness, curling, and wilting under drought stress. Their leaf activities of SOD, POD, APX, and CAT were lower than those in B104, while MDA was higher. This suggests that ZmPP2C15 positively regulates drought tolerance in maize by affecting the antioxidant enzyme activity and osmoregulatory substance content. Subcellular localization revealed that ZmPP2C15 was localized in the nucleus and cytoplasm. Yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) experiments demonstrated ZmPP2C15's interaction with ZmWIN1, ZmADT2, ZmsodC, Zmcab, and ZmLHC2. These findings establish a foundation for understanding maize PP2C gene functions, offering genetic resources and insights for molecular design breeding for drought tolerance.

Reduced SIRT1 and SIRT3 and Lower Antioxidant Capacity of Seminal Plasma Is Associated with Shorter Sperm Telomere Length in Oligospermic Men

Infertility affects millions of couples worldwide and has a profound impact not only on their families, but also on communities. Telomere attrition has been associated with infertility, DNA damage and fragmentation. Oxidative stress has been shown to affect sperm DNA integrity and telomere length. Sirtuins such as SIRT1 and SIRT3 are involved in aging and oxidative stress response. The aim of the present study is to determine the role of SIRT1 and SIRT3 in regulating oxidative stress, telomere shortening, and their association with oligospermia. Therefore, we assessed the protein levels of SIRT1 and SIRT3, total antioxidant capacity (TAC), superoxide dismutase (SOD), malondialdehyde (MDA) and catalase activity (CAT) in the seminal plasma of 272 patients with oligospermia and 251 fertile men. We also measured sperm telomere length (STL) and leukocyte telomere length (LTL) using a standard real-time quantitative PCR assay. Sperm chromatin and protamine deficiency were also measured as per standard methods. Our results for oligospermic patients demonstrate significant reductions in semen parameters, shorter STL and LTL, lower levels of SOD, TAC, CAT, SIRT1 and SIRT3 levels, and also significant protamine deficiency and higher levels of MDA and DNA fragmentation. We conclude that a shorter TL in sperms and leukocytes is associated with increased oxidative stress that also accounts for high levels of DNA fragmentation in sperms. Our results support the hypothesis that various sperm parameters in the state of oligospermia are associated with or caused by reduced levels of SIRT1 and SIRT3 proteins.

Adaptive advantages of restorative RNA editing in fungi for resolving survival-reproduction trade-offs

RNA editing in various organisms commonly restores RNA sequences to their ancestral state, but its adaptive advantages are debated. In fungi, restorative editing corrects premature stop codons in pseudogenes specifically during sexual reproduction. We characterized 71 pseudogenes and their restorative editing in Fusarium graminearum, demonstrating that restorative editing of 16 pseudogenes is crucial for germ tissue development in fruiting bodies. Our results also revealed that the emergence of premature stop codons is facilitated by restorative editing and that premature stop codons corrected by restorative editing are selectively favored over ancestral amino acid codons. Furthermore, we found that ancestral versions of pseudogenes have antagonistic effects on reproduction and survival. Restorative editing eliminates the survival costs of reproduction caused by antagonistic pleiotropy and provides a selective advantage in fungi. Our findings highlight the importance of restorative editing in the evolution of fungal complex multicellularity and provide empirical evidence that restorative editing serves as an adaptive mechanism enabling the resolution of genetic trade-offs.