Axis of ageing: telomeres, p53 and mitochondria. Nat Rev Mol Cell Biol. 2012;13:397-404. [PMID: 22588366 DOI: 10.1038/nrm3352]

Aging, Cancer, and Inflammation: The Telomerase Connection

Understanding the complex dynamics of telomere biology is important in the strong link between aging and cancer. Telomeres, the protective caps at the end of chromosomes, are central players in this connection. While their gradual shortening due to replication limits tumors expansion by triggering DNA repair mechanisms, it also promotes oncogenic changes within chromosomes, thus sustaining tumorigenesis. The enzyme telomerase, responsible for maintaining telomere length, emerges as a central player in this context. Its expression in cancer cells facilitates the preservation of telomeres, allowing them to circumvent the growth-limiting effects of short telomeres. Interestingly, the influence of telomerase extends beyond telomere maintenance, as evidenced by its involvement in promoting cell growth through alternative pathways. In this context, inflammation accelerates telomere shortening, resulting in telomere dysfunction, while telomere elements also play a role in modulating the inflammatory response. The recognition of this interplay has promoted the development of novel therapeutic approaches centered around telomerase inhibition. This review provides a comprehensive overview of the field, emphasizing recent progress in knowledge and the implications in understanding of cancer biology.

Early life exposure to mercury and relationships with telomere length and mitochondrial DNA content in European children

BACKGROUND

Telomere length (TL) and mitochondrial function expressed as mitochondrial DNA copy number (mtDNAcn) are biomarkers of aging and oxidative stress and inflammation, respectively. Methylmercury (MeHg), a common pollutant in fish, induces oxidative stress. We hypothesized that elevated oxidative stress from exposure to MeHg decreases mtDNAcn and shortens TL.

METHODS

Study participants are 6-11-year-old children from the HELIX multi-center birth cohort study, comprising six European countries. Prenatal and postnatal total mercury (THg) concentrations were measured in blood samples, TL and mtDNAcn were determined in child DNA. Covariates and confounders were obtained by questionnaires. Robust regression models were run, considering sociodemographic and lifestyle covariates, as well as fish consumption. Sex, ethnicity, and fish consumption interaction models were also run.

RESULTS

We found longer TL with higher pre- and postnatal THg blood concentrations, even at low-level THg exposure according to the RfD proposed by the US EPA. The prenatal association showed a significant linear relationship with a 3.46 % increase in TL for each unit increased THg. The postnatal association followed an inverted U-shaped marginal non-linear relationship with 1.38 % an increase in TL for each unit increased THg until reaching a cut-point at 0.96 μg/L blood THg, from which TL attrition was observed. Higher pre- and postnatal blood THg concentrations were consistently related to longer TL among cohorts and no modification effect of fish consumption nor children's sex was observed. No association between THg exposure and mtDNAcn was found.

DISCUSSION

We found evidence that THg is associated with TL but the associations seem to be time- and concentration-dependent. Further studies are needed to clarify the mechanism behind the telomere changes of THg and related health effects.

Mitochondrial microRNAs: New Emerging Players in Vascular Senescence and Atherosclerotic Cardiovascular Disease

MicroRNAs (miRNAs) are small non-coding RNAs that play an important role by controlling gene expression in the cytoplasm in almost all biological pathways. Recently, scientists discovered that miRNAs are also found within mitochondria, the energy-producing organelles of cells. These mitochondrial miRNAs, known as mitomiRs, can originate from the nuclear or mitochondrial genome, and they are pivotal in controlling mitochondrial function and metabolism. New insights indicate that mitomiRs may influence key aspects of the onset and progression of cardiovascular disease, especially concerning mitochondrial function and metabolic regulation. While the importance of mitochondria in cardiovascular health and disease is well-established, our understanding of mitomiRs' specific functions in crucial biological pathways, including energy metabolism, oxidative stress, inflammation, and cell death, is still in its early stages. Through this review, we aimed to delve into the mechanisms of mitomiR generation and their impacts on mitochondrial metabolic pathways within the context of vascular cell aging and atherosclerotic cardiovascular disease. The relatively unexplored field of mitomiR biology holds promise for future research investigations, with the potential to yield novel diagnostic tools and therapeutic interventions.

Current insights into transcriptional role(s) for the nutraceutical Withania somnifera in inflammation and aging

The health-beneficial effects of nutraceuticals in various diseases have received enhanced attention in recent years. Aging is a continuous process wherein physiological activity of an individual declines over time and is characterized by various indefinite hallmarks which contribute toward aging-related comorbidities in an individual which include many neurodegenerative diseases, cardiac problems, diabetes, bone-degeneration, and cancer. Cellular senescence is a homeostatic biological process that has an important function in driving aging. Currently, a growing body of evidence substantiates the connection between epigenetic modifications and the aging process, along with aging-related diseases. These modifications are now being recognized as promising targets for emerging therapeutic interventions. Considering that almost all the biological processes are modulated by RNAs, numerous RNA-binding proteins have been found to be linked to aging and age-related complexities. Currently, studies have shed light on the ability of the nutraceutical Withania somnifera (Ashwagandha) to influence RNA expression, stability, and processing, offering insights into its mechanisms of action. By targeting RNA-related pathways, Withania somnifera may exhibit promising effects in ameliorating age-associated molecular changes, which include modifications in gene expression and signaling networks. This review summarizes the potential role of Withania somnifera as a nutraceutical in modulating RNA-level changes associated with aging, encompassing both in vitro and in vivo studies. Taken together, the putative role(s) of Withania in modulation of key RNAs will provide insights into understanding the aging process and facilitate the development of various preventive and therapeutic strategies employing nutraceuticals for healthy aging.

Higher peripheral blood mitochondrial DNA copy number and relative telomere length in under 48 years Indonesian breast cancer patients

OBJECTIVE

Breast cancer is the leading cause of cancer incidence and mortality among Indonesian women. A comprehensive investigation is required to enhance the early detection of this disease. Mitochondrial DNA copy number (mtDNA-CN) and relative telomere length (RTL) have been proposed as potential biomarkers for several cancer risks, as they are linked through oxidative stress mechanisms. We conducted a case-control study to examine peripheral blood mtDNA-CN and RTL patterns in Indonesian breast cancer patients (n = 175) and healthy individuals (n = 181). The relative ratios of mtDNA-CN and RTL were determined using quantitative real-time PCR (qPCR).

RESULTS

Median values of mtDNA-CN and RTL were 1.62 and 0.70 in healthy subjects and 1.79 and 0.73 in breast cancer patients, respectively. We found a positive association between peripheral blood mtDNA-CN and RTL (p < 0.001). In under 48 years old breast cancer patients, higher peripheral blood mtDNA-CN (mtDNA-CN ≥ 1.73 (median), p = 0.009) and RTL (continuous variable, p = 0.010) were observed, compared to the corresponding healthy subjects. We also found a significantly higher 'High-High' pattern of mtDNA-CN and RTL in breast cancer patients under 48 years old (p = 0.011). Our findings suggest that peripheral blood mtDNA-CN and RTL could serve as additional minimally invasive biomarkers for breast cancer risk evaluation.

Fructose-1,6-bisphosphatase 1 dephosphorylates and inhibits TERT for tumor suppression

Telomere dysfunction is intricately linked to the aging process and stands out as a prominent cancer hallmark. Here we demonstrate that telomerase activity is differentially regulated in cancer and normal cells depending on the expression status of fructose-1,6-bisphosphatase 1 (FBP1). In FBP1-expressing cells, FBP1 directly interacts with and dephosphorylates telomerase reverse transcriptase (TERT) at Ser227. Dephosphorylated TERT fails to translocate into the nucleus, leading to the inhibition of telomerase activity, reduction in telomere lengths, enhanced senescence and suppressed tumor cell proliferation and growth in mice. Lipid nanoparticle-mediated delivery of FBP1 mRNA inhibits liver tumor growth. Additionally, FBP1 expression levels inversely correlate with TERT pSer227 levels in renal and hepatocellular carcinoma specimens and with poor prognosis of the patients. These findings demonstrate that FBP1 governs cell immortality through its protein phosphatase activity and uncover a unique telomerase regulation in tumor cells attributed to the downregulation or deficiency of FBP1 expression.

Prenatal air pollution exposure in relation to the telomere-mitochondrial axis of aging at birth: A systematic review

BACKGROUND

Telomere length (TL) and mitochondrial DNA (mtDNA) are central markers of vital biological mechanisms, including cellular aging. Prenatal air pollution exposure may impact molecular markers of aging leading to adverse health effects.

OBJECTIVE

To perform a systematic review on human population-based studies investigating the association between prenatal air pollution exposure and TL or mtDNA content at birth.

METHODOLOGY

Searches were undertaken on PubMed and Web of Science until July 2023. The framework of the review was based on the PRISMA-P guidelines.

RESULTS

Nineteen studies studied prenatal air pollution and TL or mtDNA content at birth. Studies investigating TL or mtDNA content measured at any other time or did not evaluate prenatal air pollution were excluded. Twelve studies (including 4381 participants with study sample range: 97 to 743 participants) investigated newborn TL and eight studies (including 3081 participants with study sample range: 120 to 743 participants) investigated mtDNA content at birth. Seven studies focused on particulate matter (PM2.5) exposure and newborn TL of which all, except two, showed an inverse association in at least one of the gestational trimesters. Of the eight studies on mtDNA content, four focused on PM2.5 air pollution with two of them reporting an inverse association. For PM2.5 exposure, observations on trimester-specific effects were inconsistent. Current literature showing associations with other prenatal air pollutants (including nitrogen oxides, sulfur dioxide, carbon monoxide and ozone) is inconsistent.

CONCLUSION

This review provides initial evidence that prenatal PM2.5 exposure impacts the telomere-mitochondrial axis of aging at birth. The current evidence did not reveal harmonious observations for trimester-specific associations nor showed consistent effects of other air pollutants. Future studies should elucidate the specific contribution of prenatal exposure to pollutants other than PM in relation to TL and mtDNA content at birth, and the potential later life health consequences.

Could Adverse Effects of Antibiotics Due to Their Use/Misuse Be Linked to Some Mechanisms Related to Nonalcoholic Fatty Liver Disease?

Nonalcoholic fatty liver disease, recently re-named metabolic dysfunction-associated steatotic fatty liver disease, is considered the most prevalent liver disease worldwide. Its molecular initiation events are multiple and not always well-defined, comprising insulin resistance, chronic low-grade inflammation, gut dysbiosis, and mitochondrial dysfunction, all of them acting on genetic and epigenetic grounds. Nowadays, there is a growing public health threat, which is antibiotic excessive use and misuse. This widespread use of antibiotics not only in humans, but also in animals has led to the presence of residues in derived foods, such as milk and dairy products. Furthermore, antibiotics have been used for many decades to control certain bacterial diseases in high-value fruit and vegetables. Recently, it has been emphasised that antibiotic-induced changes in microbial composition reduce microbial diversity and alter the functional attributes of the microbiota. These antibiotic residues impact human gut flora, setting in motion a chain of events that leads straight to various metabolic alterations that can ultimately contribute to the onset and progression of NAFLD.

Folic acid alleviated oxidative stress-induced telomere attrition and inhibited apoptosis of neurocytes in old rats

PURPOSE

Oxidative stress has been reported to cause telomere attrition, which triggers cell apoptosis. Apoptosis of neurocytes may play an essential role in the pathogenesis of neurodegenerative diseases. This study hypothesized that folic acid (FA) supplementation decreased neurocyte apoptosis by alleviating oxidative stress-induced telomere attrition in 25-month-old Sprague Dawley (SD) rats.

METHODS

Three-month-old male SD rats were randomly divided into four diet groups by different concentrations of folic acid in equal numbers, with intervention for 22 months. Folate, homocysteine (Hcy), reactive oxygen species (ROS) levels, antioxidant activities, and telomere length in the brain tissues were tested at 11, 18, and 22 months of intervention, and 8-hydroxy-deoxyguanosine (8-OHdG) levels, neurocyte apoptosis and telomere length in the cerebral cortex and hippocampal regions were tested during the 22-month intervention. An automated chemiluminescence system, auto-chemistry analyzer, Q-FISH, qPCR, and TUNEL assay were used in this study.

RESULTS

The rats had lower folate concentrations and higher Hcy, ROS, and 8-OHdG concentrations in brain tissue with aging. However, FA supplementation increased folate concentrations and antioxidant activities while decreasing Hcy, ROS, and 8-OHdG levels in rat brain tissue after 11, 18, and 22 months of intervention. Furthermore, FA supplementation alleviated telomere length shortening and inhibited neurocyte apoptosis during the 22-month intervention.

CONCLUSION

FA supplementation alleviated oxidative stress-induced telomere attrition and inhibited apoptosis of neurocytes in 25-month-old rats.

Unlocking longevity: the role of telomeres and its targeting interventions

Average life expectancy has been steadily increasing in developed countries worldwide. These demographic changes are associated with an ever-growing social and economic strain to healthcare systems as well as society. The aging process typically manifests as a decline in physiological and cognitive functions, accompanied by a rise in chronic diseases. Consequently, strategies that both mitigate age-related diseases and promote healthy aging are urgently needed. Telomere attrition, characterized by the shortening of telomeres with each cell division, paradoxically serves as both a protective mechanism and a contributor to tissue degeneration and age-related ailments. Based on the essential role of telomere biology in aging, research efforts aim to develop approaches designed to counteract telomere attrition, aiming to delay or reduce age-related diseases. In this review, telomere biology and its role in aging and age-related diseases is summarized along with recent approaches to interfere with telomere shortening aiming at well- and healthy-aging as well as longevity. As aging research enters a new era, this review emphasizes telomere-targeting therapeutics, including telomerase activators and tankyrase inhibitors, while also exploring the effects of antioxidative and anti-inflammatory agents, along with indirectly related approaches like statins.

Telomere Length, Mitochondrial DNA, and Micronucleus Yield in Response to Oxidative Stress in Peripheral Blood Mononuclear Cells

Telomere shortening, chromosomal damage, and mitochondrial dysfunction are major initiators of cell aging and biomarkers of many diseases. However, the underlying correlations between nuclear and mitochondrial DNA alterations remain unclear. We investigated the relationship between telomere length (TL) and micronucleus (MN) and their association with mitochondrial DNA copy number (mtDNAcn) in peripheral blood mononuclear cells (PBMCs) in response to 100 μM and 200 μM of hydrogen peroxide (H2O2) at 44, 72, and 96 h. Significant TL shortening was observed after both doses of H2O2 and at all times (all p < 0.05). A concomitant increase in MN was found at 72 h (p < 0.01) and persisted at 96 h (p < 0.01). An increase in mtDNAcn (p = 0.04) at 200 µM of H2O2 was also found. In PBMCs treated with 200 µM H2O2, a significant inverse correlation was found between TL and MN (r = -0.76, p = 0.03), and mtDNA content was directly correlated with TL (r = 0.6, p = 0.04) and inversely related to MN (r = -0.78, p = 0.02). Telomere shortening is the main triggering mechanism of chromosomal damage in stimulated T lymphocytes under oxidative stress. The significant correlations between nuclear DNA damage and mtDNAcn support the notion of a telomere-mitochondria axis that might influence age-associated pathologies and be a target for the development of relevant anti-aging drugs.

Association of sleep quality and mitochondrial DNA copy number in healthy middle-aged adults

OBJECTIVES

Mitochondria contribute to various compromised health, yet the association between sleep and mitochondria remains unclear. This study investigated the association between sleep quality and mitochondrial function in healthy middle-aged adults in the Republic of Korea.

METHOD

This cross-sectional study recruited 238 middle-aged adults using convenience sampling. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI). Mitochondrial function, represented by mitochondrial DNA copy number (mtDNAcn), was measured using real-time quantitative polymerase chain reaction on peripheral blood leukocytes. Multivariate linear regression analyses were performed to determine the association between sleep quality and mtDNAcn.

RESULTS

Sleep quality was negatively associated with mtDNAcn (r = -.15, p = .025); the poor sleep quality group had a notably lower mtDNAcn compared to the good sleep quality group (t = 2.40, p = .017). Among the PSQI components, sleep latency was significantly associated with reduced mtDNAcn (r = -.18, p = .005). Univariate regression analysis revealed that mtDNAcn was significantly associated with education level (β = 0.15, p = .017), shift work (β = -0.17, p = .010), global PSQI score (β = -0.15, p = .025), and sleep latency (β = -0.18, p = .005). After adjusting for educational level and shift work in the final model, longer sleep latency was independently associated with reduced mtDNAcn (β = -.16, p = .011).

CONCLUSIONS

Poor sleep quality is associated with reduced mtDNAcn, suggesting a potential biological mechanism whereby poor sleep quality, specifically long sleep latency, accelerates cellular aging and impairs health through mitochondrial dysfunction. These findings enhance our understanding of the health effects of sleep quality and highlight the importance of screening and intervention strategies for mitochondrial dysfunction.

Investigating Genetic and Environmental Substrates of the Relationship between Positive Mental Health and Biological Aging-A Study Protocol

BACKGROUND

The Italian National Institute of Health (Istituto Superiore di Sanità) funded a 30-month project (July 2021-January 2024) to conduct a twin study of the relationships between Positive Mental Health (PMH) and cellular longevity. Only a few previous studies have focused on the biomarkers of aging in relation to psychological well-being, and none of them exploited the potential of the twin design.

METHOD

In this project, following the standard procedures of the Italian Twin Registry (ITR), we aim to recruit 200 adult twin pairs enrolled in the ITR. They are requested to complete a self-report questionnaire battery on PMH and to undergo a blood withdrawal for the assessment of aging biomarkers, i.e., telomere length and mitochondrial DNA functionality. The association between psychological and aging biomarker measures will be assessed, controlling for genetic and familial confounding effects using the twin study design.

RESULTS AND CONCLUSIONS

Biomarker assays are underway. Once data are available for the total study sample, statistical analyses will be performed. The project's results may shed light on new mechanisms underlying the mind-body connection and may prove helpful to promote psychological well-being in conjunction with biological functioning.

Emerging role and therapeutic implications of p53 in intervertebral disc degeneration

Lower back pain (LBP) is a common degenerative musculoskeletal disease that imposes a huge economic burden on both individuals and society. With the aggravation of social aging, the incidence of LBP has increased globally. Intervertebral disc degeneration (IDD) is the primary cause of LBP. Currently, IDD treatment strategies include physiotherapy, medication, and surgery; however, none can address the root cause by ending the degeneration of intervertebral discs (IVDs). However, in recent years, targeted therapy based on specific molecules has brought hope for treating IDD. The tumor suppressor gene p53 produces a transcription factor that regulates cell metabolism and survival. Recently, p53 was shown to play an important role in maintaining IVD microenvironment homeostasis by regulating IVD cell senescence, apoptosis, and metabolism by activating downstream target genes. This study reviews research progress regarding the potential role of p53 in IDD and discusses the challenges of targeting p53 in the treatment of IDD. This review will help to elucidate the pathogenesis of IDD and provide insights for the future development of precision treatments.

HALD, a human aging and longevity knowledge graph for precision gerontology and geroscience analyses

Human aging is a natural and inevitable biological process that leads to an increased risk of aging-related diseases. Developing anti-aging therapies for aging-related diseases requires a comprehensive understanding of the mechanisms and effects of aging and longevity from a multi-modal and multi-faceted perspective. However, most of the relevant knowledge is scattered in the biomedical literature, the volume of which reached 36 million in PubMed. Here, we presented HALD, a text mining-based human aging and longevity dataset of the biomedical knowledge graph from all published literature related to human aging and longevity in PubMed. HALD integrated multiple state-of-the-art natural language processing (NLP) techniques to improve the accuracy and coverage of the knowledge graph for precision gerontology and geroscience analyses. Up to September 2023, HALD had contained 12,227 entities in 10 types (gene, RNA, protein, carbohydrate, lipid, peptide, pharmaceutical preparations, toxin, mutation, and disease), 115,522 relations, 1,855 aging biomarkers, and 525 longevity biomarkers from 339,918 biomedical articles in PubMed. HALD is available at https://bis.zju.edu.cn/hald .

What matters in aging is signaling for responsiveness

Biological responsiveness refers to the capacity of living organisms to adapt to changes in both their internal and external environments through physiological and behavioral mechanisms. One of the prominent aspects of aging is the decline in this responsiveness, which can lead to a deterioration in the processes required for maintenance, survival, and growth. The vital link between physiological responsiveness and the essential life processes lies within the signaling systems. To devise effective strategies for controlling the aging process, a comprehensive reevaluation of this connecting loop is imperative. This review aims to explore the impact of aging on signaling systems responsible for responsiveness and introduce a novel perspective on intervening in the aging process by restoring the compromised responsiveness. These innovative mechanistic approaches for modulating altered responsiveness hold the potential to illuminate the development of action plans aimed at controlling the aging process and treating age-related disorders.

The rosetta stone of successful ageing: does oral health have a role?

Ageing is an inevitable aspect of life and thus successful ageing is an important focus of recent scientific efforts. The biological process of ageing is mediated through the interaction of genes with environmental factors, increasing the body's susceptibility to insults. Elucidating this process will increase our ability to prevent and treat age-related disease and consequently extend life expectancy. Notably, centenarians offer a unique perspective on the phenomenon of ageing. Current research highlights several age-associated alterations on the genetic, epigenetic and proteomic level. Consequently, nutrient sensing and mitochondrial function are altered, resulting in inflammation and exhaustion of regenerative ability.Oral health, an important contributor to overall health, remains underexplored in the context of extreme longevity. Good masticatory function ensures sufficient nutrient uptake, reducing morbidity and mortality in old age. The relationship between periodontal disease and systemic inflammatory pathologies is well established. Diabetes, rheumatoid arthritis and cardiovascular disease are among the most significant disease burdens influenced by inflammatory oral health conditions. Evidence suggests that the interaction is bi-directional, impacting progression, severity and mortality. Current models of ageing and longevity neglect an important factor in overall health and well-being, a gap that this review intends to illustrate and inspire avenues for future research.

Mitochondrial epigenetics in aging and cardiovascular diseases

Mitochondria are cellular organelles which generate adenosine triphosphate (ATP) molecules for the maintenance of cellular energy through the oxidative phosphorylation. They also regulate a variety of cellular processes including apoptosis and metabolism. Of interest, the inner part of mitochondria-the mitochondrial matrix-contains a circular molecule of DNA (mtDNA) characterised by its own transcriptional machinery. As with genomic DNA, mtDNA may also undergo nucleotide mutations that have been shown to be responsible for mitochondrial dysfunction. During physiological aging, the mitochondrial membrane potential declines and associates with enhanced mitophagy to avoid the accumulation of damaged organelles. Moreover, if the dysfunctional mitochondria are not properly cleared, this could lead to cellular dysfunction and subsequent development of several comorbidities such as cardiovascular diseases (CVDs), diabetes, respiratory and cardiovascular diseases as well as inflammatory disorders and psychiatric diseases. As reported for genomic DNA, mtDNA is also amenable to chemical modifications, namely DNA methylation. Changes in mtDNA methylation have shown to be associated with altered transcriptional programs and mitochondrial dysfunction during aging. In addition, other epigenetic signals have been observed in mitochondria, in particular the interaction between mtDNA methylation and non-coding RNAs. Mitoepigenetic modifications are also involved in the pathogenesis of CVDs where oxygen chain disruption, mitochondrial fission, and ROS formation alter cardiac energy metabolism leading to hypertrophy, hypertension, heart failure and ischemia/reperfusion injury. In the present review, we summarize current evidence on the growing importance of epigenetic changes as modulator of mitochondrial function in aging. A better understanding of the mitochondrial epigenetic landscape may pave the way for personalized therapies to prevent age-related diseases.

Dammarane-type saponins from Gynostemma pentaphyllum and their anti-aging activities via up-regulating mitochondria related proteins

The importance of mitochondria in regulation of aging has been extensively recognized and confirmed. Gynostemma pentaphyllum (Thunb.) Makino, a homology of medicine and food, has been widely utilized as dietary supplement. In this study, the transcriptome of normal cells (wild type mouse embryo fibroblasts) regulated by the 30% aqueous EtOH extract of G. pentaphyllum was firstly evaluated by RNA sequencing and the results revealed that the G. pentaphyllum could up-regulate the genes involved in oxidative phosphorylation (OXPHOS) and sirtuin (SIRT) signaling pathways, indicating its effect in promoting cell viability might be attributed to the role of improving mitochondrial functions. To further discover the bioactive compounds, sixteen undescribed dammarane-type saponins along with twenty-eight known analogues were isolated from the active extract of G. pentaphyllum. Their structures were elucidated by means of comprehensive analysis of NMR and HRMS spectroscopic data. All isolates were evaluated for the regulatory effects on SIRT3 and translocase of the outer membrane 20 (TOM20), and thirteen of them exhibited satisfactory agonist activities on both SIRT3 and TOM20 at 5 μM. Furthermore, the preliminary structure-activity relationships analysis demonstrated the additional hydroxymethyl and carbonyl groups or less sugar residues in saponins could contribute positively to the up-regulatory effect on SIRT3 and TOM20. These findings encouraged the potential roles of G. pentaphyllum and its bioactive saponins in the development of natural drugs for the treatment of aging-related diseases.

Regorafenib inhibits EphA2 phosphorylation and leads to liver damage via the ERK/MDM2/p53 axis

The hepatotoxicity of regorafenib is one of the most noteworthy concerns for patients, however the mechanism is poorly understood. Hence, there is a lack of effective intervention strategies. Here, by comparing the target with sorafenib, we show that regorafenib-induced liver injury is mainly due to its nontherapeutic target Eph receptor A2 (EphA2). EphA2 deficiency attenuated liver damage and cell apoptosis under regorafenib treatment in male mice. Mechanistically, regorafenib inhibits EphA2 Ser897 phosphorylation and reduces ubiquitination of p53 by altering the intracellular localization of mouse double minute 2 (MDM2) by affecting the extracellular signal-regulated kinase (ERK)/MDM2 axis. Meanwhile, we found that schisandrin C, which can upregulate the phosphorylation of EphA2 at Ser897 also has protective effect against the toxicity in vivo. Collectively, our findings identify the inhibition of EphA2 Ser897 phosphorylation as a key cause of regorafenib-induced hepatotoxicity, and chemical activation of EphA2 Ser897 represents a potential therapeutic strategy to prevent regorafenib-induced hepatotoxicity.

No strong association among epigenetic modifications by DNA methylation, telomere length, and physical fitness in biological aging

Cellular senescence is greatly accelerated by telomere shortening, and the steps forward in human aging are strongly influenced by environmental and lifestyle factors, whether DNA methylation (DNAm) is affected by exercise training, remains unclear. In the present study, we investigated the relationships between physiological functions, maximal oxygen uptake (VO2max), vertical jump, working memory, telomere length (TL) assessed by RT-PCR, DNA methylation-based estimation of TL (DNAmTL), and DNA methylation-based biomarkers of aging of master rowers (N = 146) and sedentary subjects (N = 95), aged between 37 and 85 years. It was found that the TL inversely correlated with chronological age. We could not detect an association between telomere length and VO2max, vertical jump, and working memory by RT-PCR method, while these physiological test results showed a correlation with DNAmTL. DNAmGrimAge and DNAmPhenoAge acceleration were inversely associated with telomere length assessed by both methods. It appears that there are no strong beneficial effects of exercise or physiological fitness on telomere shortening, however, the degree of DNA methylation is associated with telomere length.

The effect of high polycyclic aromatic hydrocarbon exposure on biological aging indicators

BACKGROUND

Aging represents a serious health and socioeconomic concern for our society. However, not all people age in the same way and air pollution has been shown to largely impact this process. We explored whether polycyclic aromatic hydrocarbons (PAHs), excellent fossil and wood burning tracers, accelerate biological aging detected by lymphocytes DNA methylation age (DNAmAge) and telomere length (TL), early nuclear DNA (nDNA) hallmarks of non-mitotic and mitotic cellular aging, and mitochondrial DNA copy number (mtDNAcn).

METHODS

The study population consisted of 49 male noncurrent-smoking coke-oven workers and 44 matched controls. Occupational and environmental sources of PAH exposures were evaluated by structured questionnaire and internal dose (urinary 1-pyrenol). We estimated Occup_PAHs, the product of 1-pyrenol and years of employment as coke-oven workers, and Environ_PAHs, from multiple items (diet, indoor and outdoor). Biological aging was determined by DNAmAge, via pyrosequencing, and by TL and mtDNAcn, via quantitative polymerase chain reaction. Genomic instability markers in lymphocytes as target dose [anti-benzo[a]pyrene diolepoxide (anti-BPDE)-DNA adduct], genetic instability (micronuclei), gene-specific (p53, IL6 and HIC1) and global (Alu and LINE-1 repeats) DNA methylation, and genetic polymorphisms (GSTM1) were also evaluated in the latent variable nDNA_changes. Structural equation modelling (SEM) analysis evaluated these multifaceted relationships.

RESULTS

In univariate analysis, biological aging was higher in coke-oven workers than controls as detected by higher percentage of subjects with biological age older than chronological age (AgeAcc ≥ 0, p = 0.007) and TL (p = 0.038), mtDNAcn was instead similar. Genomic instability, i.e., genotoxic and epigenetic alterations (LINE-1, p53 and Alu) and latent variable nDNA_changes were higher in workers (p < 0.001). In SEM analysis, DNAmAge and TL were positively correlated with Occup_PAHs (p < 0.0001). Instead, mtDNAcn is positively correlated with the latent variable nDNA_changes (p < 0.0001) which is in turn triggered by Occup_PAHs and Environ_PAHs.

CONCLUSIONS

Occupational PAHs exposure influences DNAmAge and TL, suggesting that PAHs target both non-mitotic and mitotic mechanisms and made coke-oven workers biologically older. Also, differences in mtDNAcn, which is modified through nDNA alterations, triggered by environmental and occupational PAH exposure, suggested a nuclear-mitochondrial core-axis of aging. By decreasing this risky gerontogenic exposure, biological aging and the consequent age-related diseases could be prevented.

Disturb mitochondrial associated proteostasis: Neurodegeneration and imperfect ageing

The disturbance in mitochondrial functions and homeostasis are the major features of neuron degenerative conditions, like Parkinson’s disease, Amyotrophic Lateral Sclerosis, and Alzheimer’s disease, along with protein misfolding. The aberrantly folded proteins are known to link with impaired mitochondrial pathways, further contributing to disease pathogenesis. Despite their central significance, the implications of mitochondrial homeostasis disruption on other organelles and cellular processes remain insufficiently explored. Here, we have reviewed the dysfunction in mitochondrial physiology, under neuron degenerating conditions. The disease misfolded proteins impact quality control mechanisms of mitochondria, such as fission, fusion, mitophagy, and proteasomal clearance, to the detriment of neuron. The adversely affected mitochondrial functional roles, like oxidative phosphorylation, calcium homeostasis, and biomolecule synthesis as well as its axes and contacts with endoplasmic reticulum and lysosomes are also discussed. Mitochondria sense and respond to multiple cytotoxic stress to make cell adapt and survive, though chronic dysfunction leads to cell death. Mitochondria and their proteins can be candidates for biomarkers and therapeutic targets. Investigation of internetworking between mitochondria and neurodegeneration proteins can enhance our holistic understanding of such conditions and help in designing more targeted therapies.

SIRT6 is a key regulator of mitochondrial function in the brain

The SIRT6 deacetylase has been implicated in DNA repair, telomere maintenance, glucose and lipid metabolism and, importantly, it has critical roles in the brain ranging from its development to neurodegeneration. Here, we combined transcriptomics and metabolomics approaches to characterize the functions of SIRT6 in mouse brains. Our analysis reveals that SIRT6 is a central regulator of mitochondrial activity in the brain. SIRT6 deficiency in the brain leads to mitochondrial deficiency with a global downregulation of mitochondria-related genes and pronounced changes in metabolite content. We suggest that SIRT6 affects mitochondrial functions through its interaction with the transcription factor YY1 that, together, regulate mitochondrial gene expression. Moreover, SIRT6 target genes include SIRT3 and SIRT4, which are significantly downregulated in SIRT6-deficient brains. Our results demonstrate that the lack of SIRT6 leads to decreased mitochondrial gene expression and metabolomic changes of TCA cycle byproducts, including increased ROS production, reduced mitochondrial number, and impaired membrane potential that can be partially rescued by restoring SIRT3 and SIRT4 levels. Importantly, the changes we observed in SIRT6-deficient brains are also occurring in aging human brains and particularly in patients with Alzheimer's, Parkinson's, Huntington's, and Amyotrophic lateral sclerosis disease. Overall, our results suggest that the reduced levels of SIRT6 in the aging brain and neurodegeneration initiate mitochondrial dysfunction by altering gene expression, ROS production, and mitochondrial decay.

The Double-Edged Role of Extracellular Vesicles in the Hallmarks of Aging

The exponential growth in the elderly population and their associated socioeconomic burden have recently brought aging research into the spotlight. To integrate current knowledge and guide potential interventions, nine biochemical pathways are summarized under the term hallmarks of aging. These hallmarks are deeply inter-related and act together to drive the aging process. Altered intercellular communication is particularly relevant since it explains how damage at the cellular level translates into age-related loss of function at the organismal level. As the main effectors of intercellular communication, extracellular vesicles (EVs) might play a key role in the aggravation or mitigation of the hallmarks of aging. This review aims to summarize this role and to provide context for the multiple emerging EV-based gerotherapeutic strategies that are currently under study.

Extracellular Vesicles and Cardiac Aging

Global population aging is a major challenge to health and socioeconomic policies. The prevalence of diseases progressively increases with aging, with cardiovascular disease being the major cause of mortality among elderly people. The allostatic overload imposed by the accumulation of cardiac senescent cells has been suggested to play a pivotal role in the aging-related deterioration of cardiovascular function. Senescent cells exhibit intrinsic disorders and release a senescence-associated secretory phenotype (SASP). Most of these SASP compounds and damaged molecules are released from senescent cells by extracellular vesicles (EVs). Once secreted, these EVs can be readily incorporated by recipient neighboring cells and elicit cellular damage or otherwise can promote extracellular matrix remodeling. This has been associated with the development of cardiac dysfunction, fibrosis, and vascular calcification, among others. The molecular signature of these EVs is highly variable and might provide important information for the development of aging-related biomarkers. Conversely, EVs released by the stem and progenitor cells can exert a rejuvenating effect, raising the possibility of future anti-aging therapies.

Prolonged Rather Than Early Childhood Parent-Child Separation Predicts Change in Molecular Markers of Cellular Aging: A Consideration of the Role of Adolescence

Early life adversity is a major risk factor for the onset of psychopathology, and cellular aging may be a mechanism underlying these associations. It is unknown whether and how the pattern (timing and duration) of parent-child separation is associated with accelerated cellular aging, particularly with respect to functional aging and replicative senescence, indexed by mitochondrial DNA copy number (mtDNAcn) elevation and telomere length (TL) attrition. This cohort study included 252 rural adolescents (mean age 11.62 years, SD: 1.56). Nearly one in five participants were persistently separated from both parents since birth. Compared with participants who never separated from their parents, adolescents with prolonged parent-child separation had higher acceleration both in functional aging and replicative senescence of cells. However, that was not the case in adolescents who experienced parent-child separation in early childhood but regained stable parental care during adolescence. These findings indicate that pubertal development reopens a window of opportunity for buffering the adverse biological effect based on significant improvements in the supportiveness of the caregiving environment relative to that in childhood. Translating such knowledge to inform intervention and prevention strategies for youths exposed to adversity is a critical goal for the field.

The association between ambient particulate matter exposure and the telomere-mitochondrial axis of aging in newborns

BACKGROUND

Particulate matter (PM) is associated with aging markers at birth, including telomeres and mitochondria. It is unclear whether markers of the core-axis of aging, i.e. tumor suppressor p53 (p53) and peroxisome proliferator-activated receptor gamma co-activator 1 alpha (PGC-1α), are associated with prenatal air pollution and whether there are underlying mechanisms.

METHODS

556 mother-newborn pairs from the ENVIRONAGE birth cohort were recruited at the East Limburg Hospital in Genk (Belgium). In placenta and cord blood, telomere length (TL) and mitochondrial DNA content (mtDNAc) were measured using quantitative real-time polymerase chain reaction (qPCR). In cord plasma, p53 and PGC-1α protein levels were measured using ELISA. Daily ambient PM_2.5 concentrations during gestation were calculated using a spatial temporal interpolation model. Distributed lag models (DLMs) were applied to assess the association between prenatal PM_2.5 exposure and each molecular marker. Mediation analysis was performed to test for underlying mechanisms.

RESULTS

A 5 µg/m³ increment in PM_2.5 exposure was associated with -11.23 % (95 % CI: -17.36 % to -4.65 %, p = 0.0012) and -7.34 % (95 % CI: -11.56 % to -2.92 %, p = 0.0014) lower placental TL during the entire pregnancy and second trimester respectively, and with -12.96 % (95 % CI: -18.84 % to -6.64 %, p < 0.001) lower placental mtDNAc during the third trimester. Furthermore, PM_2.5 exposure was associated with a 12.42 % (95 % CI: -1.07 % to 27.74 %, p = 0.059) higher cord plasma p53 protein level and a -3.69 % (95 % CI: -6.97 % to -0.31 %, p = 0.033) lower cord plasma PGC-1α protein level during the third trimester. Placental TL mediated 65 % of the negative and 17 % of the positive association between PM_2.5 and placental mtDNAc and cord plasma p53 protein levels, respectively.

CONCLUSION

Ambient PM_2.5 exposure during pregnancy is associated with markers of the core-axis of aging, with TL as a mediating factor. This study strengthens the hypothesis of the air pollution induced core-axis of aging, and may unravel a possible underlying mediating mechanism in an early-life epidemiological context.

Role of angiotensin II in aging

Aging is an inevitable progressive decline in physiological organ function that increases the chance of disease and death. The renin-angiotensin system (RAS) is involved in the regulation of vasoconstriction, fluid homeostasis, cell growth, fibrosis, inflammation, and oxidative stress. In recent years, unprecedented advancement has been made in the RAS study, particularly with the observation that angiotensin II (Ang II), the central product of the RAS, plays a significant role in aging and chronic disease burden with aging. Binding to its receptors (Ang II type 1 receptor - AT1R in particular), Ang II acts as a mediator in the aging process by increasing free radical production and, consequently, mitochondrial dysfunction and telomere attrition. In this review, we examine the physiological function of the RAS and reactive oxygen species (ROS) sources in detail, highlighting how Ang II amplifies or drives mitochondrial dysfunction and telomere attrition underlying each hallmark of aging and contributes to the development of aging and age-linked diseases. Accordingly, the Ang II/AT1R pathway opens a new preventive and therapeutic direction for delaying aging and reducing the incidence of age-related diseases in the future.

Cytosolic DNA sensor IFI16 proteins: Potential molecular integrators of interactions among the aging hallmarks

Cellular changes that are linked to aging in humans include genomic instability, telomere attrition, epigenetic alterations, mitochondrial dysfunction, cellular senescence, and altered intercellular communications. The extent of the changes in these aging hallmarks and their interactions with each other are part of the human aging. However, the molecular mechanisms through which the aging hallmarks interact with each other remain unclear. Studies have indicated a potential role for the type I interferon (IFN) and p53-inducible IFI16 proteins in interactions with the aging hallmarks. The IFI16 proteins are members of the PYHIN protein family. Proteins in the family share a DNA-binding domain (the HIN domain) and a protein-protein interaction pyrin domain (PYD). IFI16 proteins are needed for cytosolic DNA-induced activation of the cGAS-STING pathway for type I IFN (IFN-β) expression. The pathway plays an important role in aging-related inflammation (inflammaging). Further, increased levels of the IFI16 proteins potentiate the cell growth inhibitory functions of the p53 and pRb tumor suppressors proteins. Moreover, IFI16 proteins are needed for most aging hallmarks. Therefore, here we discuss how an improved understanding of the role of the IFI16 proteins in integration of the aging hallmarks has potential to improve the human health and lifespan.

Telomerase activity in ecological studies: What are its consequences for individual physiology and is there evidence for effects and trade-offs in wild populations

Increasing evidence at the cellular level is helping to provide proximate explanations for the balance between investment in growth, reproduction and somatic maintenance in wild populations. Studies of telomere dynamics have informed researchers about the loss and gain of telomere length both on a seasonal scale and across the lifespan of individuals. In addition, telomere length and telomere rate of loss seems to have evolved differently among taxonomic groups, and relate differently to organismal diversity of lifespan. So far, the mechanisms behind telomere maintenance remain elusive, although many studies have inferred a role for telomerase, an enzyme/RNA complex known to induce telomere elongation from laboratory studies. Exciting further work is also emerging that suggests telomerase (and/or its individual component parts) has a role in fitness that goes beyond the maintenance of telomere length. Here, we review the literature on telomerase biology and examine the evidence from ecological studies for the timing and extent of telomerase activation in relation to life history events associated with telomere maintenance. We suggest that the underlying mechanism is more complicated than originally anticipated, possibly involves several complimentary pathways, and is probably associated with high energetic costs. Potential pathways for future research are numerous and we outline what we see as the most promising prospects to expand our understanding of individual differences in immunity or reproduction efficiency.

No Mediation Effect of Telomere Length or Mitochondrial DNA Copy Number on the Association Between Adverse Childhood Experiences (ACEs) and Central Arterial Stiffness

Background

Adverse childhood experiences (ACEs) have been linked to increased cardiovascular disease (CVD) risk. Previous reports have suggested that accelerated biological aging—indexed by telomere length (TL) and mitochondrial DNA copy number (mtDNAcn)—may contribute to associations between ACEs and cardiovascular health outcomes. Here, we examine the potential mediating effects of TL and mtDNAcn on the association between ACEs and central arterial stiffness—an intermediate cardiovascular health outcome—as a novel pathway linking ACEs to CVD risk among young adults.

Methods and Results

One hundred and eighty‐five (n=102 women; mean age, 22.5±1.5 years) individuals provided information on ACEs. TL (kb per diploid cell) and mtDNAcn (copies per diploid cell) were quantified using quantitative polymerase chain reaction techniques. Central arterial stiffness was measured as carotid‐femoral pulse wave velocity (cfPWV; m/s). Multiple linear regression analyses were used to examine the associations between ACEs, TL, mtDNAcn, and cfPWV. ACEs were positively associated with cfPWV ( β =0.147, P =0.035). TL ( β =−0.170, P =0.011) and mtDNAcn ( β =−0.159, P =0.019) were inversely associated with cfPWV. Neither TL ( β =−0.027, P =0.726) nor mtDNAcn ( β =0.038, P =0.620) was associated with ACEs. Neither marker mediated the association between ACEs and cfPWV.

Conclusions

An increasing number of ACEs were associated with a faster cfPWV and thus, a greater degree of central arterial stiffness. ACEs were not associated with either TL or mtDNAcn, suggesting that these markers do not represent a mediating pathway linking ACEs to central arterial stiffness.

Telomeres and Telomerase in the Control of Stem Cells

Stem cells serve as a source of cellular material in embryogenesis and postnatal growth and regeneration. This requires significant proliferative potential ensured by sufficient telomere length. Telomere attrition in the stem cells and their niche cells can result in the exhaustion of the regenerative potential of high-turnover organs, causing or contributing to the onset of age-related diseases. In this review, stem cells are examined in the context of the current telomere-centric theory of cell aging, which assumes that telomere shortening depends not just on the number of cell doublings (mitotic clock) but also on the influence of various internal and external factors. The influence of the telomerase and telomere length on the functional activity of different stem cell types, as well as on their aging and prospects of use in cell therapy applications, is discussed.

Interrelationships and determinants of aging biomarkers in cord blood

BACKGROUND

Increasing evidence supports the concept of prenatal programming as an early factor in the aging process. DNA methylation age (DNAm age), global genome-wide DNA methylation (global methylation), telomere length (TL), and mitochondrial DNA content (mtDNA content) have independently been shown to be markers of aging, but their interrelationship and determinants at birth remain uncertain.

METHODS

We assessed the inter-correlation between the aging biomarkers DNAm age, global methylation, TL and mtDNA content using Pearson's correlation in 190 cord blood samples of the ENVIRONAGE birth cohort. TL and mtDNA content was measured via qPCR, while the DNA methylome was determined using the human 450K methylation Illumina microarray. Subsequently, DNAm age was calculated according to Horvath's epigenetic clock, and mean global, promoter, gene-body, and intergenic DNA methylation were determined. Path analysis, a form of structural equation modeling, was performed to disentangle the complex causal relationships among the aging biomarkers and their potential determinants.

RESULTS

DNAm age was inversely correlated with global methylation (r = -0.64, p < 0.001) and mtDNA content (r = - 0.16, p = 0.027). Cord blood TL was correlated with mtDNA content (r = 0.26, p < 0.001) but not with global methylation or DNAm age. Path analysis showed the strongest effect for global methylation on DNAm age with a decrease of 0.64 standard deviations (SD) in DNAm age for each SD (0.01%) increase in global methylation (p < 0.001). Among the applied covariates, newborn sex and season of delivery were the strongest determinants of aging biomarkers.

CONCLUSIONS

We provide insight into molecular aging signatures at the start of life, including their interrelations and determinants, showing that cord blood DNAm age is inversely associated with global methylation and mtDNA content but not with newborn telomere length. Our findings demonstrate that cord blood TL and DNAm age relate to different pathways/mechanisms of biological aging and can be influenced by environmental factors already at the start of life. These findings are relevant for understanding fetal programming and for the early prevention of noncommunicable diseases.

Association between the peripartum maternal and fetal telomere lengths and mitochondrial DNA copy numbers and preeclampsia: a prospective case-control study

Purpose

To explore changes in telomere length (TL) and mitochondrial copy number (mtDNA-CN) in preeclampsia (PE) and to evaluate the combined effect of maternal TL and mtDNA-CN on PE risk.

Methods

A case–control study of 471 subjects (130 PE cases and 341 age frequency matched controls with gestational age rank from 24 to 42 weeks) was conducted in Nanjing Drum Tower Hospital, Jiangsu Province of China. Relative telomere length (RTL) and mtDNA-CN were measured using quantitative polymerase chain reaction (qPCR), and PE risk was compared between groups by logistic regression analyses.

Results

PE patients displayed longer RTL (0.48 versus 0.30) and higher mtDNA-CN (3.02 versus 2.00) in maternal blood as well as longer RTL (0.61 versus 0.35) but lower mtDNA-CN (1.69 versus 5.49) in cord blood (all p < 0.001). Exercise during pregnancy exerted an obvious effect of maternal telomere length prolongation. Multiparous women with folic acid intake during early pregnancy and those who delivered vaginally showed longer telomere length, while those factors imposed no or opposite effect on RTL in PE cases. Furthermore, RTL and mtDNA-CN were positively correlated in controls (in maternal blood r = 0.18, p < 0.01; in cord blood r = 0.19, p < 0.001), but this correlation was disrupted in PE patients in both maternal blood and cord blood. Longer maternal RTL and higher mtDNA-CN were associated with a higher risk of PE, and the ROC curve of RTL and mtDNA-CN for predicting PE risk presented an AUC of 0.755 (95% CI: 0.698–0.812).

Conclusions

The interaction of TL and mtDNA-CN may play an important role in the pathogenesis of PE and could be a potential biomarker of PE risk.

Supplementary information

The online version contains supplementary material available at 10.1186/s12884-022-04801-0.

P53 regulates mitochondrial biogenesis via transcriptionally induction of mitochondrial ribosomal protein L12

The well-documented tumor suppressor p53 is also a major stress response factor for its diverse regulation on cellular energetics. However, the effect of p53 on mitochondrial biogenesis, which plays a predominant role in response to the elevated energy demands, appears to be pleiotropic in various conditions and has not reached agreement. Mitochondrial ribosomal protein L12 (MRPL12), reported as a bi-functional protein for its roles in both mitochondrial ribosomes and transcriptional complexes, is a core regulatory component in mitochondrial biogenesis. Here we proved that MRPL12 is transcriptionally regulated by p53. Furthermore, the p53/MRPL12 regulation of mitochondria is part of the signaling pathway that maintains the basal mitochondrial content and positively coordinates the mitochondrial biogenesis and oxidative phosphorylation (OXPHOS) in response to metabolic perturbation. Since p53 serves as the'Guardian of the Genome', our findings may revealed a new mechanism underlying the conditions when more ATP is warranted to maintain the genome integrity and cell survival. Therefore the pharmacological intervention or metabolic modulation (e.g., through fasting or exercise) of the p53/MRPL12 pathway promises to be a therapeutic approach that can safeguard health.

Relative Telomere Length Is Associated With Age-Related Macular Degeneration in Women

Purpose

Relative telomere length (RTL) is a biomarker for physiological aging. Premature shortening of telomeres is associated with oxidative stress, which is one possible pathway that might contribute to age-related macular degeneration (AMD). We therefore aimed to investigate the association between RTL and AMD in a well-characterized group of elderly individuals.

Methods

We measured RTL in participants of the AugUR study using a multiplex quantitative PCR-based assay determining the ratio between the telomere product and a single-copy gene product (T/S ratio). AMD was assessed by manual grading of color fundus images using the Three Continent AMD Consortium Severity Scale.

Results

Among the 2262 individuals 70 to 95 years old (627 with AMD and 1635 without AMD), RTL was significantly shorter in individuals with AMD compared to AMD-free participants. In age- and sex-adjusted logistic regression analyses, we observed an 8% higher odds for AMD per 0.1 unit shorter RTL (odds ratio [OR] = 1.08; 95% confidence interval [CI], 1.02-1.14; P = 0.005). The estimates remained stable when adjusted for smoking, high-density lipoprotein cholesterol, cardiovascular disease, diabetes, and hypertension. Interestingly, this association was only present in women (OR = 1.14; 95% CI, 1.06-1.23; P < 0.001), but not in men (OR = 1.01; 95% CI, 0.93-1.10; P = 0.76). A significant sex-by-RTL interaction on AMD was detected (P = 0.043).

Conclusions

Our results show an association of RTL with AMD that was restricted to women. This is in line with altered reactive oxygen species levels and higher telomerase activity in women and provides an indication for a sex-differential pathway for oxidative stress and AMD.

Telomere length and vitamin B12

Telomeres are non-coding nucleoprotein structures consisting of a highly conserved tandem repeat DNA sequence that caps the ends of chromosomes in eukaryotes. Telomeres confer chromosomal stability, protect the genome from nucleolytic degradation, avoid aberrant recombination and improper repair, and prevent random fusion of chromosomes. The end-replication problem results in telomere shortening with every cell division, eventually leading to cellular senescence and aging. Telomere length (TL) is thereby an ideal candidate for "biological aging." Telomeres possess guanine-rich repeats, which are highly susceptible to oxidative stress. Epidemiological studies have indicated the association of telomere attrition with mortality and various age-related diseases. Micronutrients comprising vitamins and minerals act as potential modulators of stress and can influence TL. Research has indicated that vitamin B12 (B12) regulates oxidative stress and maintains genomic stability, thereby influencing telomere integrity and cellular aging. The deficiency of B12 leads to elevated levels of homocysteine, which reduces the methylation potential and increases oxidative stress, thereby compromising the TL. Telomere shortening and mitochondrial dysfunction are independently linked to aging. However, they are connected through telomerase reverse transcriptase activity, which regulates mitochondrial biogenesis. Further, experimental evidence indicated the positive association of B12 with relative TL and mitochondrial DNA copy number, an indirect index of mitochondrial biogenesis. The present chapter provides some insights into the role of B12 in influencing TL. Exploring their association might open new avenues to understand the pathophysiology of aging and age-related diseases.

Glyphosate and AMPA exposure in relation to markers of biological aging in an adult population-based study

BACKGROUND/AIM

Glyphosate, a broad-spectrum herbicide, and its main metabolite aminomethylphosphonic acid (AMPA) are persistent in the environment. Studies showed associations between glyphosate or AMPA exposure and several adverse cellular processes, including metabolic alterations and oxidative stress.

OBJECTIVE

To determine the association between glyphosate and AMPA exposure and biomarkers of biological aging.

METHODS

We examined glyphosate and AMPA exposure, mtDNA content and leukocyte telomere length in 181 adults, included in the third cycle of the Flemish Environment and Health Study (FLEHSIII). DNA was isolated from leukocytes and the relative mtDNA content and telomere length were determined using qPCR. Urinary glyphosate and AMPA concentrations were measured by Gas Chromatography-Tandem Mass Spectrometry (GC-MS-MS). We used multiple linear regression models to associate mtDNA content and leukocyte telomere length with glyphosate or AMPA exposure while adjusting for confounding variables.

RESULTS

A doubling in urinary AMPA concentration was associated with 5.19% (95% CI: 0.49 to 10.11; p = 0.03) longer leukocyte telomere length, while no association was observed with urinary glyphosate concentration. No association between mtDNA content and urinary glyphosate nor AMPA levels was observed.

CONCLUSIONS

This study showed that AMPA exposure may be associated with telomere biology in adults.

The telomere-mitochondrial axis of aging in newborns

Aging starts at the beginning of life as evidenced by high variability in telomere length (TL) and mitochondrial DNA content (mtDNAc) at birth. Whether p53 and PGC-1α are connected to these age-related markers in early life is unclear. In this study, we hypothesized that these hallmarks of aging are associated at birth.

In 613 newborns from the ENVIRONAGE birth cohort, p53 and PGC-1α protein levels were measured in cord plasma, while TL and mtDNAc were measured in both cord blood and placental tissue. Cord blood methylation data of genes corresponding to the measured protein levels were available from the Human MethylationEPIC 850K BeadChip array. Pearson correlations and linear regression models were applied while accounting for selected covariates. In cord, a 10% increase in TL was associated with 5.22% (95% CI: 3.26 to 7.22; p < 0.0001) higher mtDNAc and −2.66% (95% CI: –5.04 to −0.23%; p = 0.032) lower p53 plasma level. In placenta, a 10% increase in TL was associated with 5.46% (95% CI: 3.82 to 7.13%; p < 0.0001) higher mtDNAc and −2.42% (95% CI: −4.29 to −0.52; p = 0.0098) lower p53 plasma level. Methylation level of TP53 was correlated with TL and mtDNAc in cord blood and with cord plasma p53 level.

Our study suggests that p53 may be an important factor both at the protein and methylation level for the telomere-mitochondrial axis of aging at birth.

BaZiBuShen alleviates cognitive deficits and regulates Sirt6/NRF2/HO-1 and Sirt6/P53-PGC-1α-TERT signaling pathways in aging mice

ETHNOPHARMACOLOGICAL RELEVANCE

BaZiBuShen formula (BZBS) is clinically used to counteract mental fatigue and to retard the aging process. Brain aging echoes in major risks of human sufferings and has become one of the main challenges to our societies and the health-care systems.

AIM OF THE STUDY

To investigate the effect and mode of action of BZBS on aging-associated cognitive impairments.

MATERIALS AND METHODS

BZBS was orally administered to D-galactose and NaNO2-induced aging mice. Premature senescence was assessed using the Morris water maze, step-down type passive avoidance, and pole-climbing tests. Telomere length was examined by qPCR analysis. Telomerase activity was assessed using PCR ELISA assay. Mitochondrial complex IV activity was examined by biochemical test. The levels of redox and immune status were determined by ELISA or biochemical assay. The expressions of sirtuin 6 (Sirt6), peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), P53, telomerase reverse transcriptase (TERT), heme oxygenase-1 (HO-1), phospho(p)-nuclear factor erythroid-2 related factor 2 (NRF2), caspase-3, Bcl-2 associated x (Bax), and B-cell lymphoma-2 (Bcl-2) in the cerebral cortex were examined by Western blot and/or immunohistochemical staining.

RESULTS

BZBS intervention ameliorated reduced brain performances in aging mice, including memory, cognitive, and motor functions. In addition, BZBS administration to aging mice preserved redox homeostasis, attenuated immunosenescence, and maintained telomerase activity and telomere length. Moreover, BZBS treatment were associated with a declines in P53, caspase-3, Bax expressions and an increase in Sirt6, p-HO-1, p-NRF2, PGC-1α, and Bcl-2 expressions in the brains of this rapid aging mouse.

CONCLUSIONS

BZBS attenuates premature senescence possibly via the preservation of redox homeostasis and telomere integrity, and inhibition of apoptosis in rapid aging mouse. The mechanism governing the alterations may be associated with through the activation of Sirt6/NRF2/HO-1 and Sirt6/P53-PGC-1α-TERT signaling pathways. The results suggest that BZBS may provide a novel strategy for confronting aging and age-associated diseases.

Ageing, Age-Related Cardiovascular Risk and the Beneficial Role of Natural Components Intake

Ageing, in a natural way, leads to the gradual worsening of the functional capacity of all systems and, eventually, to death. This process is strongly associated with higher metabolic and oxidative stress, low-grade inflammation, accumulation of DNA mutations and increased levels of related damage. Detrimental changes that accumulate in body cells and tissues with time raise the vulnerability to environmental challenges and enhance the risk of major chronic diseases and mortality. There are several theses concerning the mechanisms of ageing: genetic, free radical telomerase, mitochondrial decline, metabolic damage, cellular senescence, neuroendocrine theory, Hay-flick limit and membrane theories, cellular death as well as the accumulation of toxic and non-toxic garbage. Moreover, ageing is associated with structural changes within the myocardium, cardiac conduction system, the endocardium as well as the vasculature. With time, the cardiac structures lose elasticity, and fibrotic changes occur in the heart valves. Ageing is also associated with a higher risk of atherosclerosis. The results of studies suggest that some natural compounds may slow down this process and protect against age-related diseases. Animal studies imply that some of them may prolong the lifespan; however, this trend is not so obvious in humans.

The exposome in practice: an exploratory panel study of biomarkers of air pollutant exposure in Chinese people aged 60-69 years (China BAPE Study)

The exposome overhauls conventional environmental health impact research paradigms and provides a novel methodological framework that comprehensively addresses the complex, highly dynamic interplays of exogenous exposures, endogenous exposures, and modifiable factors in humans. Holistic assessments of the adverse health effects and systematic elucidation of the mechanisms underlying environmental exposures are major scientific challenges with widespread societal implications. However, to date, few studies have comprehensively and simultaneously measured airborne pollutant exposures and explored the associated biomarkers in susceptible healthy elderly subjects, potentially resulting in the suboptimal assessment and management of health risks. To demonstrate the exposome paradigm, we describe the rationale and design of a comprehensive biomarker and biomonitoring panel study to systematically explore the association between individual airborne exposure and adverse health outcomes. We used a combination of personal monitoring for airborne pollutants, extensive human biomonitoring, advanced omics analysis, confounding information, and statistical methods. We established an exploratory panel study of Biomarkers of Air Pollutant Exposure in Chinese people aged 60-69 years (China BAPE), which included 76 healthy residents from a representative community in Jinan City, Shandong Province. During the period between September 2018 and January 2019, we conducted prospective longitudinal monitoring with a 3-day assessment every month. This project: (1) leveraged advanced tools for personal airborne exposure monitoring (external exposures); (2) comprehensively characterized biological samples for exogenous and endogenous compounds (e.g., targeted and untargeted monitoring) and multi-omics scale measurements to explore potential biomarkers and putative toxicity pathways; and (3) systematically evaluated the relationships between personal exposure to air pollutants, and novel biomarkers of exposures and effects using exposome-wide association study approaches. These findings will contribute to our understanding of the mechanisms underlying the adverse health impacts of air pollution exposures and identify potential adverse clinical outcomes that can facilitate the development of effective prevention and targeted intervention techniques.

Transcriptome-Wide Analysis of Human Liver Reveals Age-Related Differences in the Expression of Select Functional Gene Clusters and Evidence for a PPP1R10-Governed 'Aging Cascade'

A transcriptome-wide analysis of human liver for demonstrating differences between young and old humans has not yet been performed. However, identifying major age-related alterations in hepatic gene expression may pinpoint ontogenetic shifts with important hepatic and systemic consequences, provide novel pharmacogenetic information, offer clues to efficiently counteract symptoms of old age, and improve the overarching understanding of individual decline. Next-generation sequencing (NGS) data analyzed by the Mann-Whitney nonparametric test and Ensemble Feature Selection (EFS) bioinformatics identified 44 transcripts among 60,617 total and 19,986 protein-encoding transcripts that significantly (p = 0.0003 to 0.0464) and strikingly (EFS score > 0.3:16 transcripts; EFS score > 0.2:28 transcripts) differ between young and old livers. Most of these age-related transcripts were assigned to the categories 'regulome', 'inflammaging', 'regeneration', and 'pharmacogenes'. NGS results were confirmed by quantitative real-time polymerase chain reaction. Our results have important implications for the areas of ontogeny/aging and the age-dependent increase in major liver diseases. Finally, we present a broadly substantiated and testable hypothesis on a genetically governed 'aging cascade', wherein PPP1R10 acts as a putative ontogenetic master regulator, prominently flanked by IGFALS and DUSP1. This transcriptome-wide analysis of human liver offers potential clues towards developing safer and improved therapeutic interventions against major liver diseases and increased insights into key mechanisms underlying aging.

Role of mismatch repair in aging

A common feature of aging is the accumulation of genetic damage throughout life. DNA damage can lead to genomic instability. Many diseases associated with premature aging are a result of increased accumulation of DNA damage. In order to minimize these damages, organisms have evolved a complex network of DNA repair mechanisms, including mismatch repair (MMR). In this review, we detail the effects of MMR on genomic instability and its role in aging emphasizing on the association between MMR and the other hallmarks of aging, serving to drive or amplify these mechanisms. These hallmarks include telomere attrition, epigenetic alterations, mitochondrial dysfunction, altered nutrient sensing and cell senescence. The close relationship between MMR and these markers may provide prevention and treatment strategies, to reduce the incidence of age-related diseases and promote the healthy aging of human beings.

Mitochondrial Contributions to Hematopoietic Stem Cell Aging

Mitochondrial dysfunction and stem cell exhaustion are two hallmarks of aging. In the hematopoietic system, aging is linked to imbalanced immune response and reduced regenerative capacity in hematopoietic stem cells (HSCs), as well as an increased predisposition to a spectrum of diseases, including myelodysplastic syndrome and acute myeloid leukemia. Myeloid-biased differentiation and loss of polarity are distinct features of aged HSCs, which generally exhibit enhanced mitochondrial oxidative phosphorylation and increased production of reactive oxygen species (ROS), suggesting a direct role for mitochondria in the degenerative process. Here, we provide an overview of current knowledge of the mitochondrial mechanisms that contribute to age-related phenotypes in HSCs. These include mitochondrial ROS production, alteration/activation of mitochondrial metabolism, the quality control pathway of mitochondria, and inflammation. Greater understanding of the key machineries of HSC aging will allow us to identify new therapeutic targets for preventing, delaying, or even reversing aspects of this process.

Meta-analyses of maternal exposure to atmospheric particulate matter and risk of congenital anomalies in offspring

Congenital anomalies are the main causes of infant death and disability. Previous studies have suggested that maternal exposure to particulate matter is related to congenital malformation. However, the conclusions of this study remain controversial. Hence, meta-analyses were performed to assess the relationship between maternal exposure to particulate matter and the risk of congenital anomalies. The Medline, Embase, and Web of Science databases were systemically searched from inception until August 2020 to find articles related to birth defects and particulate matter. The pooled risk estimated for the combination of pollution outcomes was calculated for each study by performing fixed effects or random effects models. The existence of heterogeneity and publication bias in relevant studies was also examined. Thirty studies were included in the analysis. A statistically increased summary risk valuation was found. PM₁₀ exposure was associated with an increased risk of congenital heart disease, neural tube defects, and cleft lip with or without cleft palate (OR per 10 μg/m³ = 1.05, 95% CI, 1.03-1.07; OR per 10 μg/m³ = 1.04, 95% CI, 1.01-1.06; OR per 10 μg/m³ = 1.03, 95% CI, 1.01-1.06). Maternal exposure to particulate matter might be associated with an increased risk of congenital anomalies. Our results indicate the dangers of particulate matter exposure on fetal development and the importance of protection against exposure to such particles during pregnancy. The schematic representation of the association between maternal exposure to PM_2.5/PM₁₀ and congenital anomalies in offspring, and geographic distribution of the included reports in the meta-analyses.

The Changes in the p53 Protein across the Animal Kingdom Point to Its Involvement in Longevity

Recently, the quest for the mythical fountain of youth has produced extensive research programs that aim to extend the healthy lifespan of humans. Despite advances in our understanding of the aging process, the surprisingly extended lifespan and cancer resistance of some animal species remain unexplained. The p53 protein plays a crucial role in tumor suppression, tissue homeostasis, and aging. Long-lived, cancer-free African elephants have 20 copies of the TP53 gene, including 19 retrogenes (38 alleles), which are partially active, whereas humans possess only one copy of TP53 and have an estimated cancer mortality rate of 11–25%. The mechanism through which p53 contributes to the resolution of the Peto’s paradox in Animalia remains vague. Thus, in this work, we took advantage of the available datasets and inspected the p53 amino acid sequence of phylogenetically related organisms that show variations in their lifespans. We discovered new correlations between specific amino acid deviations in p53 and the lifespans across different animal species. We found that species with extended lifespans have certain characteristic amino acid substitutions in the p53 DNA-binding domain that alter its function, as depicted from the Phenotypic Annotation of p53 Mutations, using the PROVEAN tool or SWISS-MODEL workflow. In addition, the loop 2 region of the human p53 DNA-binding domain was identified as the longest region that was associated with longevity. The 3D model revealed variations in the loop 2 structure in long-lived species when compared with human p53. Our findings show a direct association between specific amino acid residues in p53 protein, changes in p53 functionality, and the extended animal lifespan, and further highlight the importance of p53 protein in aging.