Telomere tracking from birth to adulthood and residential traffic exposure

Sex-specific effects of maternal blood pressure on newborn telomere length: A prospective study

OBJECTIVE

To investigate the relationship between maternal blood pressure (BP) and neonatal cord blood telomere length (TL) during pregnancy, and to clarify the sensitive period.

METHODS

We conducted a prospective cohort study with 621 mother-newborn pairs from the Guangxi Zhuang Birth Cohort (GZBC) in China. Multiple informant models, restricted cubic spline regression (RCS) models, and quantile regression models were conducted to analyze the correlation between maternal BP and neonatal TL.

RESULTS

Maternal diastolic blood pressure (DBP) was inversely related to neonatal cord blood TL in the second trimester (P = 0.015) and the third trimester (P = 0.011). There was a male-specific relationship between maternal BP and neonatal TL. A 1 mmHg increment in maternal systolic blood pressure (SBP) and DBP during the second trimester was related with 0.42% (95% CI: -0.80%, -0.04%) and 0.61% (95% CI: -1.13%, -0.09%) shorter TL in male newborns, respectively. Per unit increase of maternal DBP during the third trimester was related with 0.54% (95% CI: -1.03%, -0.05%) shorter TL in male newborns. Pregnant women with hypertensive disease of pregnancy (HDP) had male offspring with shorter TL (P = 0.003). However, no significant relationships were found in female newborns (P = 0.570).

CONCLUSION

Maternal BP during pregnancy is inversely correlated with male neonatal TL and the second and third trimesters are sensitive windows.

Associations Between Early-Life Adversity, Ambient Air Pollution, and Telomere Length in Children

OBJECTIVE

Examine the independent associations and interaction between early-life adversity and residential ambient air pollution exposure on relative buccal telomere length (rBTL).

METHODS

Experiences of abuse, neglect, household challenges, and related life events were identified in a cross-sectional sample of children aged 1 to 11 years ( n = 197) using the 17-item Pediatric ACEs and Related Life Event Screener (PEARLS) tool. The PEARLS tool was analyzed both as a total score and across established domains (Maltreatment, Household Challenges, and Social Context). Ground-level fine particulate matter (PM 2.5 ) concentrations were matched to residential locations for the 1 and 12 months before biospecimen collection. We used multivariable linear regression models to examine for independent associations between continuous PM 2.5 exposure and PEARLS score/domains with rBTL. In addition, effect modification by PEARLS scores and domains on associations between PM 2.5 exposure and rBTL was examined.

RESULTS

Study participants were 47% girls, with mean (standard deviation) age of 5.9 (3.4) years, median reported PEARLS score of 2 (interquartile range [IQR], 4), median 12-month prior PM 2.5 concentrations of 11.8 μg/m 3 (IQR, 2.7 μg/m 3 ), median 1-month prior PM 2.5 concentrations of 10.9 μg/m 3 (IQR, 5.8 μg/m 3 ), and rBTL of 0.1 (IQR, 0.03). Mean 12-month prior PM 2.5 exposure was inversely associated with rBTL ( β = -0.02, 95% confidence interval = -0.04 to -0.01). Although reported PEARLS scores and domains were not independently associated with rBTL, we observed a greater decrement in rBTL with increment of average annual PM 2.5 as reported Social Context domain items increased ( p -interaction < .05).

CONCLUSIONS

Our results suggest that adverse Social Context factors may accelerate the association between chronic PM 2.5 exposure on telomere shortening during childhood.

Sedentary Behaviour and Telomere Length Shortening during Early Childhood: Evidence from the Multicentre Prospective INMA Cohort Study

Sedentary behaviour (SB) may be related to telomere length (TL) attrition due to a possible pro-inflammatory effect. This study examined the association between parent-reported sedentary behaviour (SB) and leukocyte TL at the age of 4 and telomere tracking from 4 to 8 years. In the Spanish birth cohort Infancia y Medio Ambiente (INMA) project, we analysed data from children who attended follow-up visits at age 4 (n = 669) and 8 (n = 530). Multiple robust regression models were used to explore the associations between mean daily hours of SB (screen time, other sedentary activities, and total SB) at 4 years categorised into tertiles and TL at 4 years and difference in TL rank between age 4 and 8, respectively. At the age of 4, the results showed that children with the highest screen time (1.6-5.0 h/day) had a shorter TL of -3.9% (95% CI: -7.4, -0.4; p = 0.03) compared with children in the lowest tertile (0.0-1.0 h/day). Between 4 and 8 years, a higher screen time (highest tertile group vs. lowest tertile) was associated with a decrease in the LTL rank of -1.9% (95% CI: -3.8, -0.1; p = 0.03) from 4 to 8 years. Children exposed to a higher screen time at 4 years were more prone to have shorter TL at 4 and between 4 and 8 years of age. This study supports the potential negative effect of SB during childhood on cellular longevity.

Early-life residential green spaces and traffic exposure in association with young adult body composition: a longitudinal birth cohort study of twins

BACKGROUND

Globally, the rapid increase of obesity is reaching alarming proportions. A new approach to reduce obesity and its comorbidities involves tackling the built environment. Environmental influences seem to play an important role, but the environmental influences in early life on adult body composition have not been thoroughly investigated. This study seeks to fill the research gap by examining early-life exposure to residential green spaces and traffic exposure in association with body composition among a population of young adult twins.

METHODS

As part of the East Flanders Prospective Twin Survey (EFPTS) cohort, this study included 332 twins. Residential addresses of the mothers at time of birth of the twins were geocoded to determine residential green spaces and traffic exposure. To capture body composition, body mass index, waist-to-hip ratio (WHR), waist circumference, skinfold thickness, leptin levels, and fat percentage were measured at adult age. Linear mixed modelling analyses were conducted to investigate early-life environmental exposures in association with body composition, while accounting for potential confounders. In addition, moderator effects of zygosity/chorionicity, sex and socio-economic status were tested.

RESULTS

Each interquartile range (IQR) increase in distance to highway was found associated with an increase of 1.2% in WHR (95%CI 0.2-2.2%). For landcover of green spaces, each IQR increase was associated with 0.8% increase in WHR (95%CI 0.4-1.3%), 1.4% increase in waist circumference (95%CI 0.5-2.2%), and 2.3% increase in body fat (95%CI 0.2-4.4%). Stratified analyses by zygosity/chorionicity type indicated that in monozygotic monochorionic twins, each IQR increase in land cover of green spaces was associated with 1.3% increase in WHR (95%CI 0.5-2.1%). In monozygotic dichorionic twins, each IQR increase in land cover of green spaces was associated with 1.4% increase in waist-circumference (95%CI 0.6-2.2%).

CONCLUSIONS

The built environment in which mothers reside during pregnancy might play a role on body composition among young adult twins. Our study revealed that based on zygosity/chorionicity type differential effects of prenatal exposure to green spaces on body composition at adult age might exist.

Ambient air pollution exposure and telomere length: a systematic review and meta-analysis

OBJECTIVE

This study aimed to provide evidence of the associations between pre- and post-birth and adulthood air pollution exposure with telomere length.

STUDY DESIGN

The databases of PubMed, Embase, and Web of Science were searched up to June 1st, 2022 in order to include relevant observational studies and perform a systematic review and meta-analysis.

METHODS

The random-effects meta-analysis was grouped by air pollutant and exposure window (pre- and post-birth and adulthood) to evaluate the summary effect estimate. Cochran's Q and I² statistics were used to evaluate the heterogeneity among the included studies. The quality of individual studies was evaluated using the national toxicology program/office of health assessment and translation risk of bias rating tool.

RESULTS

We identified 18 studies, covering 8506 children and 2263 adults from multiple countries. We found moderate evidence that particulate matter less than 2.5 μm (PM_2.5) exposure during the entire pregnancy (-0.043, 95% CI: -0.067, -0.018), nitrogen dioxide (NO₂) exposure during the first trimester (-0.016, 95% confidence interval [CI]: -0.027, -0.005), long-term adulthood PM_2.5 exposure were associated with shortening telomere length. Mild to high between-study heterogeneity was observed for the most tested air pollutant-telomere length combinations in different exposure windows.

CONCLUSIONS

This systematic review and meta-analysis provides the evidence which strongly supports that prenatal PM_2.5 and NO₂ exposures were related to reduced telomere length, while prenatal sulfur dioxide (SO₂) and carbon monoxide (CO) exposures, childhood PM_2.5, particulate matter less than 10 μm (PM₁₀), NO₂ exposures and short-term adulthood PM_2.5 and PM₁₀ exposures were not associated with telomere length. Further high-quality studies are needed to elaborate our suggestive associations.

Genetic regulation of newborn telomere length is mediated and modified by DNA methylation

Telomere length at birth determines later life telomere length and potentially predicts ageing-related diseases. However, the genetic and epigenetic settings of telomere length in newborns have not been analyzed. In addition, no study yet has reported how the interplay between genetic variants and genome-wide cytosine methylation explains the variation in early-life telomere length. In this study based on 281 mother-newborn pairs from the ENVIRONAGE birth cohort, telomere length and whole-genome DNA methylation were assessed in cord blood and 26 candidate single nucleotide polymorphism related to ageing or telomere length were genotyped. We identified three genetic variants associated with cord blood telomere length and 57 cis methylation quantitative trait loci (cis-mQTLs) of which 22 mQTLs confirmed previous findings and 35 were newly identified. Five SNPs were found to have significant indirect effects on cord blood telomere length via the mediating CpGs. The association between rs911874 (SOD2) and newborn telomere length was modified by nearby DNA methylation indicated by a significant statistical interaction. Our results suggest that DNA methylation in cis might have a mediation or modification effect on the genetic difference in newborn telomere length. This novel approach warrants future follow-up studies that are needed to further confirm and extend these findings.

A multi-exposure approach to study telomere dynamics in childhood: A role for residential green space and waist circumference

BACKGROUND

Telomeres are vulnerable to various environmental exposures and lifestyle factors, encompassed in the exposome. Recent research shows that telomere length is substantially determined early in life and that exposures in childhood may have important consequences in setting later life telomere length.

OBJECTIVES

We explore in a child population the associations of 17 exposures with telomere length and longitudinal telomere change.

METHODS

Children (2.8-10.3y at baseline, 51.3% boys) were followed-up for five to seven years. Relative telomere length was measured at baseline and follow-up using quantitative real-time PCR. Exposures and lifestyle factors included: body composition (body mass index and waist circumference), dietary habits (sugar- and fat-rich food intake, vegetables and fruit intake), psychosocial stress (events, emotions, behaviour), sleep duration, physical activity, and residential environmental quality (longterm black carbon, particulate matter exposure, and residential green space). Cross-sectional (n=182) and longitudinal (n=150) analyses were assessed using linear regression models, adjusting for age, sex, socioeconomic status and multiple testing.

RESULTS

Our longitudinal analyses showed that higher residential green space at baseline was associated with (β=0.261, p=0.002) lower telomere attrition and that children with a higher waist circumference at baseline showed a higher telomere attrition (β=-0.287, p=0.001). These two predictors were confirmed via LASSO variable selection and correction for multiple testing. In addition, children with more unhealthy exposures at baseline had a significantly higher telomere attrition over the follow-up period compared to children with more healthy exposures (β=-0.200, p=0.017).

DISCUSSION

Waist circumference and residential green space were identified as predictors associated with telomere attrition in childhood. These results further support the advantages of a healthy lifestyle from early age onwards and the importance of a green environment to promote molecular longevity from childhood onwards.

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.

Shorter periconception maternal telomere length and the risk of congenital cardiac outflow defects in the offspring

BACKGROUND

Congenital cardiac outflow defects (COD) are the largest group of congenital heart defects, with ventricular septal defect (VSD) as the most prevalent phenotype. Increased maternal age, excessive oxidative stress and inflammation are involved in the pathophysiology of COD and enhance telomere length (TL) shortening. We investigated the association between periconception maternal TL and the risk of having a child with COD.

METHODS

From a multicentre case-control trial, 306 case mothers of a child with COD and 424 control mothers of a child without a congenital malformation were selected. Relative TL was measured by qPCR. Multivariable logistic regression was used to compute crude and adjusted odds ratios, per standard deviation decrease, between maternal T/S ratio and COD and VSD risk. Adjustments were made for maternal age. Additional adjustments were made in a second model.

RESULTS

Shorter maternal relative TL was significantly associated with an OR of 1.29 (95% CI 1.04-1.61), p = .02, for the risk of VSD in offspring, which remained significant after an adjustment for maternal age (adjOR 1.25(95% CI 1.01-1.55), p = .04). No association between maternal TL and the risk of overall COD in offspring was observed.

CONCLUSION

Shorter maternal relative TL is associated with an approximately 1.3-OR for the risk, per SD in relative TL shortening, of VSD in the offspring. These findings need further confirmation in other studies on the predictive value of maternal TL.

Air pollution and molecular changes in age-related diseases

Assessment of the impact that air contaminants have on health is difficult as this is a complex mixture of substances that varies depending on the time and place. There are many studies on the association between air pollution and increased morbidity and mortality. Before the effect of polluted air is manifested at the level of the organs, an impact can be observed at the molecular level. These include some new biomarkers, like a shortening of the mean telomere length in DNA, dysregulation of gene expression caused by microRNA levels or a variation in the copy number of mitochondrial DNA. These changes may predispose individuals to premature development of age-related diseases and consequently to shortening of life. The common attribute, shared by changes at the molecular level and the development of diseases, is the presence of oxidative stress.

Telomere length and urinary 8-hydroxy-2'-deoxyguanosine and essential trace element concentrations in female Japanese university students

Telomere length is thought to be a biomarker of biological aging. This study examined whether telomere length was associated with urinary concentrations of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a biomarker of oxidative stress, and antioxidative trace elements in 73 female Japanese university students (age: 19.2 ± 0.7 years). We quantified 8-OHdG and selenium in urine by liquid chromatography-mass spectrometry and inductively coupled plasma-mass spectrometry, respectively. Telomere length and urinary concentrations of other essential trace elements (molybdenum, cobalt, and chromium) that were previously measured in the same study participants, were used in this study. We used multiple linear regression analysis to examine the associations of telomere length with urinary 8-OHdG and essential trace element concentrations (covariates: urinary cotinine concentration, age, BMI, and drinking status). The geometric means (geometric standard deviation) of 8-OHdG and selenium were 3.4 (1.5) and 31 (1.3) µg/g creatinine, respectively. Telomere length was not associated with urinary 8-OHdG concentration, but was negatively associated with urinary selenium concentration. In conclusion, telomere length was not associated with urinary 8-OHdG concentration in the young women in this study. Longitudinal studies should be conducted to clarify the association between telomere shortening rate and oxidative stress level.

Genetic, Environmental and Lifestyle Determinants of Accelerated Telomere Attrition as Contributors to Risk and Severity of Multiple Sclerosis

Telomeres are protective structures at the ends of linear chromosomes. Shortened telomere lengths (TL) are an indicator of premature biological aging and have been associated with a wide spectrum of disorders, including multiple sclerosis (MS). MS is a chronic inflammatory, demyelinating and neurodegenerative disease of the central nervous system. The exact cause of MS is still unclear. Here, we provide an overview of genetic, environmental and lifestyle factors that have been described to influence TL and to contribute to susceptibility to MS and possibly disease severity. We show that several early-life factors are linked to both reduced TL and higher risk of MS, e.g., adolescent obesity, lack of physical activity, smoking and vitamin D deficiency. This suggests that the mechanisms underlying the disease are connected to cellular aging and senescence promoted by increased inflammation and oxidative stress. Additional prospective research is needed to clearly define the extent to which lifestyle changes can slow down disease progression and prevent accelerated telomere loss in individual patients. It is also important to further elucidate the interactions between shared determinants of TL and MS. In future, cell type-specific studies and advanced TL measurement methods could help to better understand how telomeres may be causally involved in disease processes and to uncover novel opportunities for improved biomarkers and therapeutic interventions in MS.

Telomeres: New players in immune-mediated inflammatory diseases?

Telomeres are repetitive DNA sequences located at the ends of linear chromosomes that preserve the integrity and stability of the genome. Telomere dysfunctions due to short telomeres or altered telomere structures can ultimately lead to replicative cellular senescence and chromosomal instability, both mechanisms being hallmarks of ageing. Chronic inflammation, oxidative stress and finally telomere length (TL) dynamics have been shown to be involved in various age-related non-communicable diseases (NCDs). Immune-mediated inflammatory diseases (IMIDs), including affections such as inflammatory bowel disease, psoriasis, rheumatoid arthritis, spondyloarthritis and uveitis belong to this group of age-related NCDs. Although in recent years, we have witnessed the emergence of studies in the literature linking these IMIDs to TL dynamics, the causality between these diseases and telomere attrition is still unclear and controversial. In this review, we provide an overview of available studies on telomere dynamics and discuss the utility of TL measurements in immune-mediated inflammatory diseases.

Serum gamma-glutamyl transferase, a marker of alcohol intake, is associated with telomere length and cardiometabolic risk in young adulthood

Studies based on self-reported alcohol consumption and telomere length show inconsistent results. Therefore, we studied the association between gamma-glutamyl transferase (GGT), a widely used biomarker of alcohol intake, and telomere length. The possible health relevance in young adulthood was explored by investigating cardiometabolic risk factors. Mixed modelling was performed to examine GGT and alcohol consumption in association with telomere length in buccal cells of 211 adults between 18 and 30 years old of the East Flanders Prospective Twin Survey. In addition, we investigated the association between GGT and cardiometabolic risk factors; waist circumference, systolic blood pressure, fasting glucose, HDL cholesterol, and triglycerides. Although we did not observe an association between self-reported alcohol consumption and telomere length, our results show that a doubling in serum GGT is associated with 7.80% (95% CI − 13.9 to − 1.2%; p = 0.02) shorter buccal telomeres, independently from sex, chronological age, educational level, zygosity and chorionicity, waist-to-hip ratio and smoking. The association between GGT was significant for all five cardiometabolic risk factors, while adjusting for age. We show that GGT, a widely used biomarker of alcohol consumption, is associated with telomere length and with risk factors of cardiometabolic syndrome, despite the young age of this study population.

Different epigenetic signatures of newborn telomere length and telomere attrition rate in early life

Telomere length (TL) and telomere shortening are biological indicators of aging, and epigenetic associates have been found for TL in adults. However, the role of epigenetic signatures in setting newborn TL and early life telomere dynamics is unknown. In the present study, based on 247 participating newborns from the ENVIRONAGE birth cohort, whole-genome DNA methylation, profiled on the Illumina MethylationEPIC BeadChip microarray, and TL were measured in cord blood. In a follow-up visit at a mean age of 4.58 years, leukocyte TL was evaluated. We combined an epigenome-wide association study and a statistical learning method with re-sampling to select CpGs and their two-way interactions to model baseline (cord blood) TL and early-life telomere attrition rate, where distinct epigenetic signatures were identified for the two outcomes. In addition, a stronger epigenetic regulation was suggested in setting newborn TL than that of telomere dynamics in early life: 47 CpGs and 7 between-CpG interactions explained 76% of the variance in baseline TLs, while 72% of the total variance in telomere attrition rate was explained by 31 CpGs and 5 interactions. Functional enrichment analysis based on the selected CpGs in the two models revealed GLUT4 translocation and immune cell signaling pathways, respectively. These CpGs and interactions, as well as the cellular pathways, are potential novel targets of further investigation of telomere biology and aging.

Pleiotropic effects of telomere length loci with brain morphology and brain tissue expression

Several studies have reported association between leukocyte telomere length (LTL) and neuropsychiatric disorders. Although telomere length is affected by environmental factors, genetic variants in certain loci are strongly associated with LTL. Thus, we aimed to identify the genomic relationship between genetic variants of LTL with brain-based regulatory changes and brain volume. We tested genetic colocalization of seven and nine LTL loci in two ancestry groups, European (EUR) and East-Asian (EAS), respectively, with brain morphology measures for 101 T1-magnetic resonance imaging-based region of interests (n = 21 821). The posterior probability (>90%) was observed for 'fourth ventricle', 'gray matter' and 'cerebellar vermal lobules I-IV' volumes. We then tested causal relationship using LTL loci for gene and methylation expression. We found causal pleiotropy for gene (EAS = four genes; EUR = five genes) and methylation expression (EUR = 17 probes; EAS = 4 probes) of brain tissues (P ≤ 2.47 × 10-6). Integrating chromatin profiles with LTL-single nucleotide polymorphisms identified 45 genes (EUR) and 79 genes (EAS) (P ≤ 9.78×10-7). We found additional 38 LTL-genes using chromatin-based gene mapping for EUR ancestry population. Gene variants in three LTL-genes-GPR37, OBFC1 and RTEL1/RTEL1-TNFRSF6B-show convergent evidence of pleiotropy with brain morphology, gene and methylation expression and chromatin association. Mapping gene functions to drug-gene interactions, we identified process 'transmission across chemical synapses' (P < 2.78 × 10-4). This study provides evidence that genetic variants of LTL have pleiotropic roles with brain-based effects that could explain the phenotypic association of LTL with several neuropsychiatric traits.

Environmental pollutants exposure: A potential contributor for aging and age-related diseases

Telomeres are "protective messengers" at the ends of eukaryotic chromosomes that protect them from degradation, end to end fusion and recombination. Admittedly, telomeres progressively shorten with age that can also be significantly accelerated by pathological conditions, which are often considered as potential contributors for cellular senescence. It is commonly believed that constant accumulation of senescent cells may lead to dysfunctional tissues and organs, thereby accelerating aging process and subsequent occurrence of age-related diseases. In particular, epidemiological data has indicated a significant association between environmental pollutants exposure and a high incidence of age-related diseases. Moreover, there is growing evidence that environmental toxicity has a detrimental impact on telomere length. Overall, a consensus is emerging that environmental pollutants exposure could lead to accelerated telomere erosion and further induce premature senescence, which may be responsible for the acceleration of aging and the high morbidity and mortality rates of age-related diseases.

Longitudinal telomere length and body composition in healthy term-born infants during the first two years of life

OBJECTIVE

Leukocyte telomere length (LTL) is one of the markers of biological aging as shortening occurs over time. Shorter LTL has been associated with adiposity and a higher risk of cardiovascular diseases. The objective was to assess LTL and LTL shortening during the first 2 years of life in healthy, term-born infants and to associate LTL shortening with potential stressors and body composition.

STUDY DESIGN

In 145 healthy, term-born infants (85 boys), we measured LTL in blood, expressed as telomere to single-gene copy ratio (T/S ratio), at 3 months and 2 years by quantitative PCR technique. Fat mass (FM) was assessed longitudinally by PEAPOD, DXA, and abdominal FM by ultrasound.

RESULTS

LTL decreased by 8.5% from 3 months to 2 years (T/S ratio 4.10 vs 3.75, p<0.001). LTL shortening from 3 months to 2 years associated with FM%(R = 0.254), FM index(R = 0.243) and visceral FM(R = 0.287) at 2 years. LTL shortening tended to associate with gain in FM% from 3 to 6 months (R = 0.155, p = 0.11), in the critical window for adiposity programming. There was a trend to a shorter LTL in boys at 2 years(p = 0.056). LTL shortening from 3 months to 2 years was not different between sexes.

CONCLUSION

We present longitudinal LTL values and show that LTL shortens considerably (8.5%) during the first 2 years of life. LTL shortening during first 2 years of life was associated with FM%, FMI and visceral FM at age 2 years, suggesting that adverse adiposity programming in early life could contribute to more LTL shortening.

Child buccal telomere length and mitochondrial DNA content as biomolecular markers of ageing in association with air pollution

BACKGROUND

Pro-inflammatory conditions such as air pollution might induce biological ageing. However, the available evidence on such an impact in children is still very scarce. We studied in primary schoolchildren the association of ambient residential air pollution exposure with telomere length (TL) and mitochondrial DNA content (mtDNAc), two important targets of the core axis of ageing.

METHODS

Between 2012 and 2014, buccal TL and mtDNAc were repeatedly assessed using qPCR in 197 Belgian primary schoolchildren (mean age 10.3 years) as part of the COGNAC study. At the child's residence, recent (week), sub-chronic (month) and chronic (year) exposure to nitrogen dioxide (NO₂), particulate matter ≤ 2.5 µm (PM_2.5) and black carbon (BC) were estimated using a high resolution spatiotemporal model. A mixed-effects model with school and subject as random effect was used while adjusting for a priori chosen covariates.

RESULTS

An interquartile range (IQR) increment (1.9 µg/m³) in chronic PM_2.5 exposure was associated with a 8.9% (95% CI: -15.4 to -1.9%) shorter TL. In contrast to PM_2.5, chronic exposure to BC and NO₂ was not associated with TL but recent exposure to BC and NO₂ showed significant inverse associations with TL: an IQR increment in recent exposure to BC (0.9 µg/m³) and NO₂ (10.2 µg/m³) was associated with a 6.2% (95% CI: -10.6 to -1.6%) and 6.4% (95% CI: -11.8 to -0.7%) shorter TL, respectively. Finally, an IQR increment in chronic PM_2.5 exposure was associated with a 12.7% (95% CI: -21.7 to -2.6%) lower mtDNAc. However, no significant associations were seen for NO₂ and BC or for other exposure windows.

CONCLUSION

Chronic exposure to PM_2.5 below the EU threshold was associated with child's shorter buccal TL and lower mtDNAc, while traffic-related pollutants (BC and NO₂) showed recent effects on telomere biology. Our data add to the literature on air pollution-induced effects of TL and mtDNAc, two measures part of the core axis of cellular ageing, from early life onwards.

Association between nutrient intake and telomere length in Japanese female university students

OBJECTIVE

Telomere length can be a biomarker of cumulative oxidative stress and inflammation indicating biological aging. Previous studies examined association of nutrient intake with telomere length targeting middle-aged and elderly individuals. This study examined whether dietary macro- and micronutrient intake was associated with telomere length in young females.

METHODS

Seventy-four Japanese young females (median (interquartile range) age was 19 (19 - 20) years) participated. We estimated their intake of nutrients (energy, protein, fat, carbohydrate, essential elements, vitamins, fatty acids, and dietary fibre) using a semi-quantitative food frequency questionnaire and measured telomere length (T/S ratio, the ratio of telomere repeat copy number (T) to single-copy gene number (S)) of DNA extracted from blood by qPCR. The association between telomere length and tertiles of nutrient intake were analysed.

RESULTS

The median (interquartile range) of telomere length was 0.70 (0.52 - 0.98). Vitamin A intake was positively associated with telomere length (tertile 1 vs. 2, coefficient [95% confidence interval] = 0.42 [0.12, 0.71]; tertile 1 vs. 3, coefficient [95% confidence interval] = 0.33 [0.04, 0.62]) after adjusting for covariates (age, BMI, passive smoking, and drinking).

CONCLUSIONS

Our findings suggest that variation in vitamin A intake might influence telomere attrition in healthy individuals.

Newborn telomere length predicts later life telomere length: Tracking telomere length from birth to child- and adulthood

Background

Telomere length (TL) is considered a biological marker of aging and may indicate age-related disease susceptibility. Adults and children show a fixed ranking and tracking of TL over time. However, the contribution of an individual's initial birth TL to their later life TL is unknown. We evaluated change and tracking of TL from birth to child- and adulthood.

Methods

Telomere length at birth was measured using qPCR in two independent prospective birth cohorts. After a median follow-up period of 4 years in ENVIRONAGE (n = 273) we assessed leukocyte telomere length (LTL) and after 23 years in EFPTS (n = 164) buccal TL was assessed. Correlations and multivariable regression models were applied to study telomere tracking and determinants of TL change from birth onwards.

Findings

In children, LTL at the age of 4 correlates with TL at the start of life both in cord blood (r = 0.71, P < 0.0001;) and placenta (r = 0.60, P < 0.0001) and was –11.2% and –33.1% shorter, respectively. In adulthood, buccal TL at the age of 23 correlates with placental TL (r = 0.46, P < 0.0001) and was –35.9% shorter. TL attrition was higher in individuals with longer birth TL. However, based on TL ranking, individuals do not tend to change dramatically from TL rank after 4 or 23 years of follow-up. Finally, longer maternal TL associates with lower telomere attrition in the next generation.

Interpretation

The high prediction of newborn TL for later life TL, and stable TL ranking from birth onwards underscores the importance of understanding the initial setting of newborn TL and its significance for later life.

Funding

European Research Council (ERC-StG310898) and Flemish Scientific Fund (12X9620N).

Telomere length in newborns is associated with exposure to low levels of air pollution during pregnancy

Telomere length (TL) is a biomarker of biological aging that may be affected by prenatal exposure to air pollution. The aim of this study was to assess the association between prenatal exposure to air pollution and TL in maternal blood cells (leukocytes), placenta and umbilical cord blood cells, sampled immediately after birth in 296 Danish mother-child pairs from a birth cohort. Exposure data was obtained using the high-resolution and spatial-temporal air pollution modeling system DEHM-UBM-AirGIS for PM_2.5, PM₁₀, SO₂, NH₄⁺, black carbon (BC), organic carbon (OC), CO, O₃, NO₂, and NO_x at residential and occupational addresses of the participating women for the full duration of the pregnancy. The association between prenatal exposure to air pollutants and TL was investigated using distributed lag models. There were significant and positive associations between TL in umbilical cord blood cells and prenatal exposure to BC, OC, NO₂, NO_x, CO, and O₃ during the second trimester. TL in umbilical cord blood was significantly and inversely associated with prenatal exposure to PM_2.5, BC, OC, SO₂, NH₄⁺, CO and NO₂ during the third trimester. There were similar inverse associations between TL from umbilical cord blood cells and air pollution exposure at the residential and occupational addresses. There were weaker or no associations between air pollution exposure and TL in placenta tissue and maternal blood cells. In conclusion, both the second and third trimesters of pregnancy are shown to be sensitive windows of exposure to air pollution affecting fetal TL.

Short Leukocyte Telomeres, But Not Telomere Attrition Rates, Predict Memory Decline in the 20-Year Longitudinal Betula Study

Leukocyte telomere length (LTL) is a proposed biomarker for aging-related disorders, including cognitive decline and dementia. Long-term longitudinal studies measuring intra-individual changes in both LTL and cognitive outcomes are scarce, precluding strong conclusions about a potential aging-related relationship between LTL shortening and cognitive decline. This study investigated associations between baseline levels and longitudinal changes in LTL and memory performance across an up to 20-year follow-up in 880 dementia-free participants from a population-based study (mean baseline age: 56.8 years, range: 40–80; 52% female). Shorter baseline LTL significantly predicted subsequent memory decline (r = .34, 95% confidence interval: 0.06, 0.82), controlling for age, sex, and other relevant covariates. No significant associations were however observed between intra-individual changes in LTL and memory, neither concurrently nor with a 5-year time-lag between LTL shortening and memory decline. These results support the notion of short LTL as a predictive factor for aging-related memory decline, but suggest that LTL dynamics in adulthood and older age may be less informative of cognitive outcomes in aging. Furthermore, the results highlight the importance of long-term longitudinal evaluation of outcomes in biomarker research.

The relation between Helicobacter pylori immunoglobulin G seropositivity and leukocyte telomere length in US adults from NHANES 1999-2000

BACKGROUND

Helicobacter pylori (H pylori) immunoglobulin G (IgG) seropositivity is prevalent but its relation with leukocyte telomere length (LTL), a cellular aging biomarker, is unclear.

METHODS

Among 3,472 participants from the National Health and Nutrition Examination Survey (NHANES) cycle 1999-2000, LTL was measured with the quantitative polymerase chain reaction. H pylori IgG was measured by enzyme-linked immunosorbent assays and defined as seropositivity with an immune status ratio score > 0.9. We used linear regression models to examine the relation of H pylori IgG seropositivity with continuous LTL and logistic regression for the relation with short LTL (<10th percentile of the population distribution) adjusting for potential confounders. We stratified the analyses by a priori selected variables.

RESULTS

Population prevalence of H pylori IgG seropositivity was 31.5% in the overall population with higher prevalence found in those with older age, other races than non-Hispanic whites, lower education, and being born out of the United States. Continuous LTL was non-significantly shorter in those with H Pylori IgG seropositivity versus seronegativity (mean difference = -40.3 bp, 95% CI: -112.4, 31.9). This difference was not significant after adjusting for potential confounders nor stratifying by potential effect modifiers. H Pylori IgG seropositivity was significantly associated with short LTL among the elderly (55-75 years, adjusted OR: 3.06, 95% CI: 1.17, 7.99), but not in the overall population (OR: 1.28, 95% CI: 0.81-2.02).

CONCLUSION

H Pylori IgG seropositivity was not associated with continuous LTL in the general population but may be associated with an excessively short LTL in the elderly.

Association of greenspace exposure with telomere length in preschool children

Exposure to greenspace has been associated with a wide range of health benefits; however, the available evidence on the association of this exposure with telomere length (TL), an early marker of ageing, is still scarce. We investigated the association of greenspace exposure with TL in a sample of 200 preschool children (aged 5-7 years) residing in Sabzevar, Iran (2017). We comprehensively characterized different aspects of greenspace exposure encompassing residential, kindergarten, and total (including both residential and kindergarten) surrounding greenspace (using satellite-derived Normalized Difference Vegetation Index), residential and kindergarten distance to green spaces, time spent in private gardens and public green spaces, and the number of plant pots at home. Relative leukocyte TL (LTL) in blood samples of the study participants was measured using quantitative polymerase chain reaction (qPCR). We applied mixed effects linear regression models with kindergarten and qPCR plate as random effects, to estimate the association of indicators of greenspace exposure (one at a time) with LTL, controlled for relevant covariates. We observed an inverse association between distance from home and kindergarten to green spaces larger than 5000 m² and LTL. Moreover, higher total surrounding greenspace at 300m and 500m buffers and higher surrounding greenspace at 300m buffer around kindergarten and home were associated with longer LTL. Furthermore, longer time spent (h/week) in the public green spaces was associated with longer LTL. Our findings for residential and kindergarten distance to any green space (regardless of the size), residential surrounding greenspace at 100m and 500m buffers, kindergarten surrounding greenspace at 100m buffer, time spent in private gardens (h/week) and the number of plant pots at home were not conclusive. Our findings were generally suggestive for a positive association between greenspace exposure and LTL in preschool children. More studies are needed to confirm these findings in other settings with different climates and populations.

Telomere Shortening in the Alzheimer's Disease Neuroimaging Initiative Cohort

BACKGROUND

Although shorter telomeres have been associated with Alzheimer's disease (AD), it is unclear whether longitudinal change in telomere length is associated with AD progression.

OBJECTIVE

To investigate the association of telomere length change with AD diagnosis and progression.

METHODS

In 653 individuals from the Alzheimer's Disease Neuroimaging Initiative (ADNI) cohort, T/S ratio (telomere versus single copy gene), a proxy of telomere length, was measured for up to five visits per participant (N = 1918 samples post-QC) using quantitative PCR (qPCR). T/S ratio was adjusted for batch effects and DNA storage time. A mixed effects model was used to evaluate association of telomere length with AD diagnostic group and interaction of age and diagnosis. Another mixed effects model was used to compare T/S ratio changes pre- to post-conversion to MCI or AD to telomere change in participants with stable diagnoses.

RESULTS

Shorter telomeres were associated with older age (Effect Size (ES) = -0.23) and male sex (ES = -0.26). Neither baseline T/S ratio (ES = -0.036) nor T/S ratio change (ES = 0.046) differed significantly between AD diagnostic groups. MCI/AD converters showed greater, but non-significant, telomere shortening compared to non-converters (ES = -0.186).

CONCLUSIONS

Although AD compared to controls showed small, non-significant effects for baseline T/S ratio and T/S ratio shortening, we did observe a larger, though still non-significant effect for greater telomere shortening in converters compared to non-converters. Although our results do not support telomere shortening as a robust biomarker of AD progression, further investigation in larger samples and for subgroups of participants may be informative.

Telomere length: how the length makes a difference

Telomerase is perceived as an immortality enzyme that might provide longevity to cells and whole organisms. Importantly, it is generally inactive in most somatic cells of healthy, adult men. Consequently, its substrates, i.e. telomeres, get shorter in most human cells with time. Noteworthy, cell life limitation due to telomere attrition during cell divisions, may not be as bad as it looks since longer cell life means longer exposition to harmful factors. Consequently, telomere length (attrition rate) becomes a factor that is responsible for inducing the signaling that leads to the elimination of cells that lived long enough to acquire severe damage. It seems that telomere length that depends on many different factors (including telomerase activity but also genetic factors, a hormonal profile that reflects sex, etc.) might become a useful marker of aging and exposition to stress. Thus in the current paper, we review the factors that affect telomere length in human cells focusing on sex that all together with different environmental and hormonal regulations as well as parental aspect affect telomere attrition rate. We also raise some limitations in the assessment of telomere length that hinders a trustworthy meta-analysis that might lead to acknowledgment of the real value of this parameter.

Placental and Cord Blood Telomere Length in Relation to Maternal Nutritional Status

BACKGROUND

The uterine environment may be important for the chromosomal telomere length (TL) at birth, which, in turn, influences disease susceptibility throughout life. However, little is known about the importance of specific nutritional factors.

OBJECTIVES

We assessed the impact of multiple maternal nutritional factors on TL in placenta and cord blood.

METHODS

In a population-based mother-child cohort in northwestern Argentina, we measured maternal weight, BMI, body fat percentage (BFP), and several nutrients [selenium, magnesium, calcium, zinc, manganese, iodine, vitamin B-12, folate, 25-hydroxycholecalciferol (25(OH)D3)], hemoglobin, and homocysteine in maternal whole blood, serum, plasma, or urine during pregnancy (mean gestational week 27). We measured the relative TL (rTL) in placenta (n = 99) and cord blood (n = 98) at delivery by real-time PCR. Associations were evaluated by multivariable-adjusted linear regression.

RESULTS

The women's prepregnancy BMI (kg/m2; mean ± SD: 23.7 ± 4.1), body weight (55.4 ± 9.9 kg), and BFP (29.9 ± 5.5%), but not height (153 ± 5.3 cm), were inversely associated with placental rTL (P < 0.01 for all), with ∼0.5 SD shorter rTL for an IQR increase in prepregnancy body weight, BMI, or BFP. Also, impedance-based BFP, but not lean body mass, in the third trimester was associated with shorter placental rTL. In addition, serum vitamin B-12 (232 ± 96 pmol/L) in pregnancy (P = 0.038), but not folate or homocysteine, was associated with shorter placental rTL (0.2 SD for an IQR increase). In contrast, plasma 25(OH)D3 (46 ± 15 nmol/L) was positively associated with placental rTL (P < 0.01), which increased by 0.4 SD for an IQR increase in 25(OH)D3. No clear associations of the studied maternal nutritional factors were found with cord blood rTL.

CONCLUSIONS

Maternal BMI, BFP, and vitamin B-12 were inversely associated, whereas 25(OH)D3 was positively associated, with placental TL. No association was observed with cord blood TL. Future studies should elucidate the role of placental TL for child health.

Telomere erosion as a placental clock: From placental pathologies to adverse pregnancy outcomes

The placenta provides nutritional and gas exchange between fetus and mother. Early in pregnancy, placental trophoblasts proliferate rapidly and invade aggressively. As pregnancy progresses, placental cells begin to age. Indeed, pregnancy itself has a tightly regulated duration, determined in large part by placental lifespan. Late in pregnancy, placental cells reach a senescent apoptotic state, activated by a number of intrinsic and extrinsic factors, including oxidative stress (OS), and DNA damage. Pregnancy complications, stillbirths and neonatal deaths have been related to OS and abnormal placental aging. Telomeres, the protective nucleoprotein structures at the ends of linear chromosomes, shorten both from cell replication and from exposure to OS. When telomeres become critically short they trigger cell cycle arrest and eventually cell death. Telomere attrition thus provide an intrinsic mechanism to explain tissue senescence and aging. Mounting evidence suggests that senescence of placental and fetal membrane cells results from telomere attrition. We review the studies that have addressed the role of telomere length (TL) in placentas from normal and complicated pregnancies, including pre-eclampsia, intrauterine growth restriction, gestational diabetes, and stillbirth. To date studies have uncovered associations between TL and a number of obstetrical complications. Future research is needed to determine whether these associations are causative, i.e. whether these clinical conditions result from telomere dysfunction, and whether particular features of telomeres, e.g. mean or shortest length, etc. could serve as clinically useful biomarkers of placental health.

Association of exposure to air pollution and telomere length in preschool children

Exposure to air pollution is associated with adverse health effects; however, the available evidence of its association with telomere length (TL), an early marker of ageing, in children is still scarce with no study available for preschool children. This study aimed to investigate the association of exposure to air pollution and traffic indicators at home and kindergarten with relative leukocyte TL (LTL) in preschool children. This cross-sectional study included 200 preschool children (5-7 years old) recruited from 27 kindergartens in Sabzevar, Iran (2017). Outdoor annual average levels PM₁, PM_2.5, and PM₁₀ at residential address and kindergartens were estimated applying land use regression (LUR) models. Moreover, indoor levels of PMs at kindergartens were measured for four days in each season resulting in a total of 16 days of measurements for each kindergarten. Total streets length in different buffers and distance to major road were calculated as traffic indicators at residential address and kindergartens. We applied quantitative real-time polymerase chain reaction (qRT-PCR) to measure relative LTL in blood samples obtained from children. Mixed linear regression models were developed with qPCR plate and kindergarten as random effects, to estimate association of each pollutant and traffic indicator with LTL, controlled for relevant covariates. Higher concentrations of outdoor PM₁, PM_2.5, and PM₁₀, at home and kindergartens were associated with shorter relative LTL. Similarly, increase in indoor PM_2.5 concentrations at kindergartens was associated with shorter relative LTL (β = -0.18, 95% CI: -0.36, -0.01, P-value < 0.01). Moreover, higher total street length in 100 m buffer around residence and lower residential distance to major roads were associated with shorter relative LTL (β = -0.25, 95% CI: -0.37, -0.13, P-value < 0.01, and 0.32, 95% CI: 0.20, 0.44, P-value < 0.01, respectively). Overall, our study suggested that higher exposure to air pollution and traffic at kindergarten and residential home were associated with shorter relative LTL in preschool children.

Preconception telomere length as a novel maternal biomarker to assess the risk of spina bifida in the offspring

BACKGROUND

Periconception interactions between maternal conditions and environmental and genetic factors are involved in the pathogenesis and prevention of neural tube defects (NTD), such as spina bifida. These factors have in common that they can impair the oxidative pathway, resulting in excessive (chronic) oxidative stress and inflammation.

METHODS

Review of the literature concerning underlying mechanisms and biomarkers of aging particularly during reproduction. A number of molecular markers for biological aging have been identified, including telomere length (TL). Excessive telomere shortening is an index of senescence, causes genomic instability and is associated with a higher risk of age-related diseases. Furthermore, TL shortening is associated with the similar environmental and lifestyle exposures associated with NTD risk.

RESULTS

Embryonic mice deficient in the telomerase gene show shorter TL and failure of closure of the neural tube as the main defect, suggesting that this developmental process is among the most sensitive to telomere loss and chromosomal instability.

CONCLUSIONS

From this background, we hypothesize that preconceptional long term exposure to harmful environmental and lifestyle risk factors accelerates a woman's aging process, which can be measured by TL, and thereby her underlying risk of NTD offspring. Alternatively, it might be that women with an increased NTD risk already exhibit a more advanced biological age before the onset of pregnancy compared to women of identical calendar age.

Association of Parental Socioeconomic Status and Newborn Telomere Length

IMPORTANCE

Low socioeconomic status is associated with higher all-cause mortality and risks for aging-related diseases. Biological aging is a potential process underlying health conditions related to social disadvantages, which may be present from birth onward.

OBJECTIVE

To evaluate the association of parental socioeconomic status with telomere length (TL) at birth, a marker of biological aging.

DESIGN, SETTING, AND PARTICIPANTS

This prospective birth cohort study was conducted among 1504 mother-newborn pairs in Belgium recruited between February 1, 2010, and July 1, 2017.

EXPOSURES

Parental socioeconomic measures, including maternal educational level, occupation, paternal educational level, and neighborhood income based on median annual household income.

MAIN OUTCOMES AND MEASURES

Mean relative TL was measured in cord blood and placental tissue. By constructing a principal component, an integrative socioeconomic measure was derived that integrates parental socioeconomic status and neighborhood income. Multivariable adjusted regression analyses were performed to associate the integrative socioeconomic measure and TL at birth.

RESULTS

In 1026 newborns (517 boys; mean [SD] gestational age, 39.2 [1.4] weeks), a higher socioeconomic status was associated with longer cord blood TL and placental TL. Each unit increment in the integrative socioeconomic status measure was associated with 2.1% (95% CI, 0.9%-3.4%; P < .001) longer cord blood TL in boys, while no association was observed for girls (0.5% longer cord blood TL; 95% CI, -0.9% to 1.8%; P = .50). The sex-specific socioeconomic status interaction revealed a stronger association in boys compared with newborn girls (1.6%; 95% CI, 0.02%-3.3%; P = .047 for interaction). In placental tissue, higher socioeconomic status was associated with 1.8% (95% CI, 0.3%-3.3%; P = .02) longer TL in newborn boys but not in girls (0.4% longer TL; 95% CI, -1.2% to 2.0%; P = .63). For placental tissue, no sex and socioeconomic status interaction on TL was observed (1.4%; 95% CI, -0.5% to 3.4%; P = .16 for interaction).

CONCLUSIONS AND RELEVANCE

This study suggests that parental socioeconomic status is associated with newborn TL, especially in boys. The results indicate that familial social economic factors are associated with the potential cellular longevity of the next generation, with a potential higher transgenerational vulnerability for newborn boys.

Early life tobacco exposure and children's telomere length: The HELIX project

Telomere length and mitochondrial DNA content are considered biomarkers of cellular aging, oxidative stress, and inflammation, but there is almost no information on their association with tobacco smoke exposure in fetal and early life. The aim of this study was to assess whether prenatal and childhood tobacco exposure were associated with leukocyte telomere length (LTL) and mitochondrial DNA (mtDNA) content in children. As part of a multi-centre European birth cohort study HELIX (Human Early-Life Exposome) (n = 1396) we assessed maternal smoking status during pregnancy through questionnaires, and through urinary cotinine levels that were then used to classify women as not exposed to smoking (<10 µg/L), exposed to secondhand smoke (SHS) (10-50 µg/L) and active smokers (>50 µg/L). When the children were around 8 years of age (range: 5.4-12.0 years), childhood SHS tobacco smoke exposure was assessed through an extensive questionnaire and through measurements of urinary cotinine (<3.03 µg/L non-detected, >3.03 µg/L detected). Leukocyte mtDNA content and LTL were measured in the children at 8 years employing real time polymerase chain reaction (qPCR). Effect estimates were calculated using multivariate linear regression models for prenatal and childhood exposures adjusted for potential confounders. Maternal cotinine levels indicative of SHS exposure during pregnancy were associated with a decrease of 3.90% in LTL in children (95% CI: -6.68, -0.91), compared with non-smoking, whereas the association for maternal cotinine levels indicative of active smoking did not reach statistical significance (-3.24%; 95% CI: -6.59, 0.21). Childhood SHS tobacco exposure was not associated with LTL in children. Global SHS exposure during childhood was associated with an increase of 3.51% (95% CI: 0.78, 6.27) in mtDNA content. Our findings suggest that tobacco smoke exposure during pregnancy, even at SHS levels, may accelerate telomere shortening in children and thus induce biological aging from an early age.

Antiaging effect of a Jianpi-yangwei formula in Caenorhabditis elegans

Background

Jianpi-yangwei (JPYW), a traditional Chinese medicine (TCM), helps to nourish the stomach and spleen and is primarily used to treat functional declines related to aging. This study aimed to explore the antiaging effects and mechanism of JPYW by employing a Caenorhabditis elegans model.

Methods

Wild-type C. elegans N2 worms were cultured in growth medium with or without JPYW, and lifespan analysis, oxidative and heat stress resistance assays, and other aging-related assays were performed. The effects of JPYW on the levels of superoxide dismutase (SOD) and the expression of specific genes were examined to explore the underlying mechanism of JPYW.

Results

Compared to control worms, JPYW-treated wild-type worms showed increased survival times under both normal and stress conditions (P < 0.05). JPYW-treated worms also exhibited enhanced reproduction, movement and growth and decreased intestinal lipofuscin accumulation compared to controls (P < 0.05). Furthermore, increased activity of SOD, downregulated expression levels of the proaging gene clk-2 and upregulated expression levels of the antiaging genes daf-16, skn-1, and sir-2.1 were observed in the JPYW group compared to the control group.

Conclusion

Our findings suggest that JPYW extends the lifespan of C. elegans and exerts antiaging effects by increasing the activity of an antioxidant enzyme (SOD) and by regulating the expression of aging-related genes. This study not only indicates that this Chinese compound exerts antiaging effects by activating and repressing target genes but also provides a proven methodology for studying the biological mechanisms of TCMs.

Early Biological Aging and Fetal Exposure to High and Low Ambient Temperature: A Birth Cohort Study

BACKGROUND

Although studies have provided estimates of premature mortality to either heat or cold in adult populations, and fetal exposure to ambient temperature may be associated with life expectancy, the effects of temperature on aging in early life have not yet been studied. Telomere length (TL) is a marker of biological aging, and a short TL at birth may predict lifespan and disease susceptibility later in life.

OBJECTIVES

We studied to what extent prenatal ambient temperature exposure is associated with newborn TL.

METHODS

In the ENVIRONAGE (ENVIRonmental influence ON early AGEing) birth cohort in Flanders, Belgium, we measured cord blood and placental TL in 1,103 mother-newborn pairs (singletons with ≥36wk of gestation) using a quantitative real-time polymerase chain reaction (qPCR) method. We associated newborn TL with average weekly exposure to ambient temperature using distributed lag nonlinear models (DLNMs) while controlling for potential confounders. Double-threshold DLNMs were used to estimate cold and heat thresholds and the linear associations between temperature and TL below the cold threshold and above the heat threshold.

RESULTS

Prenatal temperature exposure above the heat threshold (19.5°C) was associated with shorter cord blood TL. The association with a 1°C increase in temperature was strongest at week 36 of gestation and resulted in a 3.29% [95% confidence interval (CI): -4.67, -1.88] shorter cord blood TL. Consistently, prenatal temperature exposure below the cold threshold (5.0°C) was associated with longer cord blood TL. The association with a 1°C decrease in temperature was strongest at week 10 of gestation with 0.72% (95% CI: 0.46, 0.97) longer cord blood TL.

DISCUSSION

Our study supports potential effects of prenatal temperature exposure on longevity and disease susceptibility later in life. Future climate scenarios might jeopardize the potential molecular longevity of future generations from birth onward. https://doi.org/10.1289/EHP5153.

Telomere dynamic in humans and animals: Review and perspectives in environmental toxicology

Telomeres (TLs) play major roles in stabilizing the genome and are usually shortened with ageing. The maintenance of TLs is ensured by two mechanisms involving telomerase (TA) enzyme and alternative lengthening telomeres (ALT). TL shortening and/or TA inhibition have been related to health effects on organisms (leading to reduced reproductive lifespan and survival), suggesting that they could be key processes in toxicity mechanisms (at molecular and cellular levels) and relevant as an early warning of exposure and effect of chemicals on human health and animal population dynamics. Consequently, a critical analysis of knowledge about relationships between TL dynamic and environmental pollution is essential to highlight the relevance of TL measurement in environmental toxicology. The first objective of this review is to provide a survey on the basic knowledge about TL structure, roles, maintenance mechanisms and causes of shortening in both vertebrates (including humans) and invertebrates. Overall, TL length decreases with ageing but some unexpected exceptions are reported (e.g., in species with different lifespans, such as the nematode Caenorhabditis elegans or the crustacean Homarus americanus). Inconsistent results reported in various biological groups or even between species of the same genus (e.g., the microcrustacean Daphnia sp.) indicate that the relation usually proposed between TL shortening and a decrease in TA activity cannot be generalized and depends on the species, stage of development or lifespan. Although the scientific literature provides evidence of the effect of ageing on TL shortening, much less information on the relationships between shortening, maintenance of TLs, influence of other endogenous and environmental drivers, including exposure to chemical pollutants, is available, especially in invertebrates. The second objective of this review is to connect knowledge on TL dynamic and exposure to contaminants. Most of the studies published on humans rely on correlative epidemiological approaches and few in vitro experiments. They have shown TL attrition when exposed to contaminants, such as polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCB), pesticides and metallic elements (ME). In other vertebrates, the studies we found deals mainly with birds and, overall, report a disturbance of TL dynamic consecutively to exposure to chemicals, including metals and organic compounds. In invertebrates, no data are available and the potential of TL dynamic in environmental risk assessment remains to be explored. On the basis of the main gaps identified some research perspectives (e.g., impact of endogenous and environmental drivers, dose response effects, link between TL length, TA activity, longevity and ageing) are proposed to better understand the potential of TL and TA measurements in humans and animals in environmental toxicology.

Air pollution-induced placental alterations: an interplay of oxidative stress, epigenetics, and the aging phenotype?

According to the "Developmental Origins of Health and Disease" (DOHaD) concept, the early-life environment is a critical period for fetal programming. Given the epidemiological evidence that air pollution exposure during pregnancy adversely affects newborn outcomes such as birth weight and preterm birth, there is a need to pay attention to underlying modes of action to better understand not only these air pollution-induced early health effects but also its later-life consequences. In this review, we give an overview of air pollution-induced placental molecular alterations observed in the ENVIRONAGE birth cohort and evaluate the existing evidence. In general, we showed that prenatal exposure to air pollution is associated with nitrosative stress and epigenetic alterations in the placenta. Adversely affected CpG targets were involved in cellular processes including DNA repair, circadian rhythm, and energy metabolism. For miRNA expression, specific air pollution exposure windows were associated with altered miR-20a, miR-21, miR-146a, and miR-222 expression. Early-life aging markers including telomere length and mitochondrial DNA content are associated with air pollution exposure during pregnancy. Previously, we proposed the air pollution-induced telomere-mitochondrial aging hypothesis with a direct link between telomeres and mitochondria. Here, we extend this view with a potential co-interaction of different biological mechanisms on the level of placental oxidative stress, epigenetics, aging, and energy metabolism. Investigating the placenta is an opportunity for future research as it may help to understand the fundamental biology underpinning the DOHaD concept through the interactions between the underlying modes of action, prenatal environment, and disease risk in later life. To prevent lasting consequences from early-life exposures of air pollution, policy makers should get a basic understanding of biomolecular consequences and transgenerational risks.

The East Flanders Prospective Twin Survey (EFPTS): 55 Years Later

The East Flanders Prospective Twin Survey (EFPTS) is a registry of multiple births in the province of East Flanders, Belgium. Since its start in 1964, over 10,000 twin-pairs have been registered. EFPTS has several unique features: it is population-based and prospective, with the possibility of long-term follow-up; the twins (and higher order multiple births) are recruited at birth; basic perinatal data are recorded; chorion type and zygosity are established; since 1969, placental biopsies have been taken and frozen at -20°C for future research. Since its origin, the EFPTS has included placental data and allows differentiation of three subtypes of monozygotic twins based on the time of the initial zygotic division: the dichorionic-diamniotic pairs (early, with splitting before the fourth day after fertilization), the monochorionic-diamniotic pairs (intermediate, splitting between the fourth- and the seventh-day postfertilization) and the monochorionic-monoamniotic pairs (late, splitting after the eighth day postfertilization). Studies can be initiated taking into account primary biases, those originating 'in utero'. Such studies could throw new light on the consequences of early embryological events and the gene-environment interactions as far as periconceptional and intrauterine environment are concerned.

Smoking does not accelerate leucocyte telomere attrition: a meta-analysis of 18 longitudinal cohorts

Smoking is associated with shorter leucocyte telomere length (LTL), a biomarker of increased morbidity and reduced longevity. This association is widely interpreted as evidence that smoking causes accelerated LTL attrition in adulthood, but the evidence for this is inconsistent. We analysed the association between smoking and LTL dynamics in 18 longitudinal cohorts. The dataset included data from 12 579 adults (4678 current smokers and 7901 non-smokers) over a mean follow-up interval of 8.6 years. Meta-analysis confirmed a cross-sectional difference in LTL between smokers and non-smokers, with mean LTL 84.61 bp shorter in smokers (95% CI: 22.62 to 146.61). However, LTL attrition was only 0.51 bp yr-1 faster in smokers than in non-smokers (95% CI: -2.09 to 1.08), a difference that equates to only 1.32% of the estimated age-related loss of 38.33 bp yr-1. Assuming a linear effect of smoking, 167 years of smoking would be required to generate the observed cross-sectional difference in LTL. Therefore, the difference in LTL between smokers and non-smokers is extremely unlikely to be explained by a linear, causal effect of smoking. Selective adoption, whereby individuals with short telomeres are more likely to start smoking, needs to be considered as a more plausible explanation for the observed pattern of telomere dynamics.

Exposure to Environmental Pollutants and Their Association with Biomarkers of Aging: A Multipollutant Approach

Mitochondrial DNA (mtDNA) content and telomere length are putative aging biomarkers and are sensitive to environmental stressors, including pollutants. Our objective was to identify, from a set of environmental exposures, which exposure is associated with leukocyte mtDNA content and telomere length in adults. This study includes 175 adults from 50 to 65 years old from the cross-sectional Flemish Environment and Health study, of whom leukocyte telomere length and mtDNA content were determined using qPCR. The levels of exposure of seven metals, 11 organohalogens, and four perfluorinated compounds (PFHxS, PFNA, PFOA, PFOS) were measured. We performed sparse partial least-squares regression analyses followed by ordinary least-squares regression to assess the multipollutant associations. While accounting for possible confounders and coexposures, we identified that urinary cadmium (6.52%, 95% confidence interval, 1.06, 12.28), serum hexachlorobenzene (2.89%, 018, 5.68), and perfluorooctanesulfonic acid (11.38%, 5.97, 17.08) exposure were positively associated ( p < 0.05) with mtDNA content, while urinary copper (-9.88%, -14.82, -4.66) and serum perfluorohexanesulfonic acid (-4.75%, -8.79, -0.54) exposure were inversely associated with mtDNA content. Urinary antimony (2.69%, 0.45, 4.99) and mercury (1.91%, 0.42, 3.43) exposure were positively associated with leukocyte telomere length, while urinary copper (-3.52%, -6.60, -0.34) and serum perfluorooctanesulfonic acid (-3.64%, -6.60, -0.60) showed an inverse association. Our findings support the hypothesis that environmental pollutants interact with molecular hallmarks of aging.

Association between prenatal particulate air pollution exposure and telomere length in cord blood: Effect modification by fetal sex

INTRODUCTION

In utero particulate matter exposure produces oxidative stress that impacts cellular processes that include telomere biology. Newborn telomere length is likely critical to an individual's telomere biology; reduction in this initial telomere setting may signal increased susceptibility to adverse outcomes later in life. We examined associations between prenatal particulate matter with diameter ≤2.5 µm (PM_2.5) and relative leukocyte telomere length (LTL) measured in cord blood using a data-driven approach to characterize sensitive windows of prenatal PM_2.5 effects and explore sex differences.

METHODS

Women who were residents of Mexico City and affiliated with the Mexican Social Security System were recruited during pregnancy (n = 423 for analyses). Mothers' prenatal exposure to PM_2.5 was estimated based on residence during pregnancy using a validated satellite-based spatio-temporally resolved prediction model. Leukocyte DNA was extracted from cord blood obtained at delivery. Duplex quantitative polymerase chain reaction was used to compare the relative amplification of the telomere repeat copy number to single gene (albumin) copy number. A distributed lag model incorporating weekly averages for PM_2.5 over gestation was used in order to explore sensitive windows. Sex-specific associations were examined using Bayesian distributed lag interaction models.

RESULTS

In models that included child's sex, mother's age at delivery, prenatal environmental tobacco smoke exposure, pre-pregnancy BMI, gestational age, birth season and assay batch, we found significant associations between higher PM_2.5 exposure during early pregnancy (4-9 weeks) and shorter LTL in cord blood. We also identified two more windows at 14-19 and 34-36 weeks in which increased PM_2.5 exposure was associated with longer LTL. In stratified analyses, the mean and cumulative associations between PM_2.5 and shortened LTL were stronger in girls when compared to boys.

CONCLUSIONS

Increased PM_2.5 during specific prenatal windows was associated with shorter LTL and longer LTL. PM_2.5 was more strongly associated with shortened LTL in girls when compared to boys. Understanding sex and temporal differences in response to air pollution may provide unique insight into mechanisms.

Exploring telomere length in mother-newborn pairs in relation to exposure to multiple toxic metals and potential modifying effects by nutritional factors

BACKGROUND

The uterine environment may influence telomere length at birth, which is essential for cellular function, aging, and disease susceptibility over the lifespan. However, little is known about the impact of toxic chemicals on early-life telomeres. Therefore, we assessed the potential impact of multiple toxic metals on relative telomere length (rTL) in the maternal blood, cord blood, and placenta, as well as the potential modifying effects of pro-oxidants.

METHOD

In a mother-child cohort in northern Argentina (n = 169), we measured multiple toxic metals in the maternal blood or urine collected during late pregnancy, as well as the placenta and cord blood collected at delivery, using inductively coupled plasma mass spectrometry (ICP-MS). We assessed associations of log₂-transformed metal concentrations with rTL, measured in maternal and cord blood leukocytes and the placenta by real-time PCR, using multivariable-adjusted linear regression. Additionally, we tested for modifications by antioxidants (zinc, selenium, folate, and vitamin D₃).

RESULTS

Exposure to boron and antimony during pregnancy was associated with shorter maternal rTL, and lithium with longer maternal rTL; a doubling of exposure was associated with changes corresponding to 0.2-0.4 standard deviations (SD) of the rTL. Arsenic concentrations in the placenta (n = 98), blood, and urine were positively associated with placental rTL, about 0.2 SD by doubled arsenic. In the cord blood (n = 88), only lead was associated with rTL (inversely), particularly in boys (p for interaction 0.09). Stratifying by newborn sex showed ten times stronger association in boys (about 0.6 SD) than in girls. The studied antioxidants did not modify the associations, except that with antimony.

CONCLUSIONS

Elevated exposure to boron, lithium, arsenic, and antimony was associated with maternal or newborn rTL in a tissue-specific, for lead also sex-specific, manner. Nutritional antioxidants did not generally influence the associations.

Lung cancer risk by geologic coal deposits: A case-control study of female never-smokers from Xuanwei and Fuyuan, China

Coal types vary around the world because of geochemical differences in their source deposits; however, the influence of coal emissions from different deposits on human health remains unexplored. To address this issue, we conducted the first study of the relationship between coal use from various deposits and lung cancer risk in Xuanwei and Fuyuan, counties in China where lung cancer rates are among the highest in the world among female never-smokers due to use of bituminous ("smoky") coal for heating and cooking. We conducted a population-based case-control study of 1031 lung cancer cases and 493 controls among never-smoking women in Xuanwei and Fuyuan. Logistic regression models were used to estimate associations between coal use from various deposits across the lifecourse and lung cancer risk. There was substantial heterogeneity in risks by coal deposit (p = 7.8E-05). Compared to non-smoky coal users, risks by smoky coal deposit ranged from OR = 7.49 (95% CI: 3.43-16.38) to OR = 33.40 (95% CI: 13.07-85.34). Further, women born into homes that used smoky coal and subsequently changed to non-smoky coal had a higher risk (OR = 10.83 (95% CI: 4.61-25.46)) than women born into homes that used non-smoky coal and changed to smoky coal (OR = 4.74 (95% CI: 2.03-11.04, p_difference = 0.04)). Our study demonstrates that various sources of coal have considerably different impact on lung cancer in this population and suggests that early-life exposure to carcinogenic emissions may exert substantial influence on health risks later in life. These factors should be considered when evaluating the health risks posed by exposure to coal combustion emissions.

Sex-specific associations between telomere length and candidate miRNA expression in placenta

BACKGROUND

In the early-life environment, proper development of the placenta is essential for both fetal and maternal health. Telomere length at birth has been related to life expectancy. MicroRNAs (miRNAs) as potential epigenetic determinants of telomere length at birth have not been identified. In this study, we investigate whether placental miRNA expression is associated with placental telomere length at birth.

METHODS

We measured the expression of seven candidate miRNAs (miR-16-5p, -20a-5p, -21-5p, -34a-5p, 146a-5p, -210-3p and -222-3p) in placental tissue at birth in 203 mother-newborn (51.7% girls) pairs from the ENVIRONAGE birth cohort. We selected miRNAs known to be involved in crucial cellular processes such as inflammation, oxidative stress, cellular senescence related to aging. Placental miRNA expression and relative average placental telomere length were measured using RT-qPCR.

RESULTS

Both before and after adjustment for potential covariates including newborn's ethnicity, gestational age, paternal age, maternal smoking status, maternal educational status, parity, date of delivery and outdoor temperature during the 3rd trimester of pregnancy, placental miR-34a, miR-146a, miR-210 and miR-222 expression were significantly (p ≤ 0.03) and positively associated with placental relative telomere length in newborn girls. In newborn boys, only higher expression of placental miR-21 was weakly (p = 0.08) associated with shorter placental telomere length. Significant miRNAs explain around 6-8% of the telomere length variance at birth.

CONCLUSIONS

Placental miR-21, miR-34a, miR-146a, miR-210 and miR-222 exhibit sex-specific associations with telomere length in placenta. Our results indicate miRNA expression in placental tissue could be an important determinant in the process of aging starting from early life onwards.

Ageing at the level of telomeres in association to residential landscape and air pollution at home and work: a review of the current evidence

Studies suggest that leukocyte telomere length is an index of systemic ageing. Here, we discuss telomere length as a marker of biological ageing in relation to residential landscape (greenness), residential air pollution and work-related exposures. Telomere lengths are memories of cumulative oxidative and inflammatory stress, and show to have inverse associations with the risk of non-communicable diseases. For this reason, telomeres are considered as markers of biological ageing. Studies at birth, in children, young adulthood, and elderly show that residential green space, lower traffic exposure and long-term lower exposure to particulate air pollution are associated with longer telomeres. Work-related exposures including exposure to toxic metals, polycyclic aromatic hydrocarbons and particulate matter are associated with shorter telomeres for a given age. In contrast to chronic exposures, evidence is present of the observation that recent exposure is associated with longer telomeres. Our overview shows that the magnitude of residential and work-related environmental factors on telomere length are often as important as many classical lifestyle factors.

Retinal microcirculation and leukocyte telomere length in the general population

Retinal arteriolar narrowing increases with age and predict adverse cardiovascular outcomes. Telomere length keeps track of the division of somatic cells and is a biomarker of biological age. We investigated to what extent retinal arteriolar diameters are associated with biological age, as captured by leukocyte telomere length (LTL). In 168 randomly selected Flemish participants from the family-based population study FLEMENGHO (mean age, 46.2 years) at baseline, of whom 85 underwent a follow-up examination (median, 4.1 years), we post-processed nonmydriatic retinal photographs and measured LTL. In men only, central retinal arteriolar equivalents (CRAE) and arteriole-to-venule ratio (AVR) were associated with LTL with stronger associations at higher age and body mass index. In men aged 57.6 years (75th percentile) a 20% shorter LTL was associated with a decrease in CRAE of 4.57 µm. A 20% shorter LTL was associated with a decrease of 5.88 µm in CRAE at a BMI of 29.9 kg/m2 (75th percentile). Similar associations were observed between AVR and LTL. In women, no retinal microvascular traits were associated with LTL. Retinal arteriolar narrowing in men but not in women is associated with biological age. Our findings support the idea that avoiding overweight contributes to maintaining a healthier microcirculation.