Stress exposure in intrauterine life is associated with shorter telomere length in young adulthood

Perinatal cumulative risk scores for depression symptoms in young people from the Growing Up in New Zealand longitudinal study

BACKGROUND

Adolescent depression has increased markedly over the last decade and often persists into adulthood with a range of adverse outcomes. Identifying the perinatal risk factors contributing to adolescent depression is crucial to advise early interventions.

METHODS

The study included 4563 young people from the Growing Up in New Zealand (GUiNZ) longitudinal study who completed a questionnaire on depression symptoms at age 12 years (Centre for Epidemiological Studies Depression Scale for Children (CESD-10)). Cumulative Risk (CR) scores were created by combining the perinatal risk factors significantly associated with depression symptoms. Then, these CR scores were grouped into three levels and their association with depression symptoms was investigated in univariable and multivariable analyses.

RESULTS

We found a statistically significant association between the CR scores (from one to six perinatal risk factors) and depression score at age 12, compared to the no-risk factor group, suggesting a dose-response relationship. In the adjusted analysis, young people exposed to the low CR score (1-3 risk factors) had a 0.85 unit increase in depression score (p- < .001), and those exposed to the high CR (≥risk factors) had a 1.70 unit increase (p < .001) compared to no perinatal risk factors.

LIMITATIONS

Our model was focused on the perinatal CR score without including the effects of childhood risk factors.

CONCLUSIONS

The perinatal CR score is a valuable approach to identifying the subgroup of young people who are most at risk for depression symptoms. As such, early interventions that simultaneously address multiple perinatal risk factors for depression are recommended.

Leukocyte telomere length and memory circuitry and cognition in early aging: Impact of sex and menopausal status

Telomere length (TL) is an important cellular marker of biological aging impacting the brain and heart. However, how it is related to the brain (e.g., cognitive function and neuroanatomic architecture), and how these relationships may vary by sex and reproductive status, is not well established. Here we assessed the association between leukocyte TL and memory circuitry regional brain volumes and memory performance in early midlife, in relation to sex and reproductive status. Participants (N = 198; 95 females, 103 males; ages 45-55) underwent structural MRI and neuropsychological assessments of verbal, associative, and working memory. Overall, shorter TL was associated with smaller white matter volume in the parahippocampal gyrus and dorsolateral prefrontal cortex. In males, shorter TL was associated with worse working memory performance and corresponding smaller white matter volumes in the parahippocampal gyrus, anterior cingulate cortex, and dorsolateral prefrontal cortex. In females, the impact of cellular aging was revealed over the menopausal transition. In postmenopausal females, shorter TL was associated with poor associative memory performance and smaller grey matter volume in the right hippocampus. In contrast, TL was not related to memory performance or grey and white matter volumes in any memory circuitry region in pre/perimenopausal females. Results demonstrated that shorter TL is associated with worse memory function and smaller volume in memory circuitry regions in early midlife, an association that differs by sex and reproductive status. Taken together, TL may serve as an early indicator of sex-dependent brain abnormalities in early midlife.

Material hardship and telomere length in children

Telomere length (TL) serves as a biomarker of exposure to stressors, including material hardship. Data from the Future of Families and Child Wellbeing Study (1998-2015) were utilized to determine whether prior material hardship was associated with shorter salivary TL at years 9 and 15. 49% of the year 9 study population were female, 49% were Black, and 25% were Hispanic. At year 9 (N = 1990), regression analyses found a significant association between prior material hardship and shorter TL (β = -.005, p < .01). Additionally, at year 15 (N = 1874), material hardship experienced during infancy and toddlerhood was associated with shorter TL (β = -.009, p < .01), pointing toward infancy and toddlerhood as a sensitive period.

Robust evidence supports a causal link between higher birthweight and longer telomere length: a mendelian randomization study

Background

Observational studies have suggested a potential relationship between birthweight and telomere length. However, the causal link between these two parameters remains undefined. In this study, we use Mendelian Randomization (MR). This method employs genetic variants as instrumental variables, to explore the existence of causal associations and elucidate the causal relationship between birth weight and telomere length.

Methods

We used 35 single nucleotide polymorphisms (SNPs) as instrumental variables for birth weight. These SNPs were identified from a meta-analysis involving 153,781 individuals. Furthermore, we obtained summary statistics for telomere length from a study conducted on 472,174 United Kingdom Biobank participants. To evaluate the causal estimates, we applied the random effect inverse variance weighted method (IVW) and several other MR methods, such as MR-Egger, weighted median, and MR-PRESSO, to verify the reliability of our findings.

Results

Our analysis supports a significant causal relationship between genetically predicted birth weight and telomer3e length. The inverse variance weighted analysis results for birth weight (Beta = 0.048; 95%CI = 0.023 to 0.073; p < 0.001) corroborate this association.

Conclusion

Our study provides robust evidence supporting a causal link between higher birth weight and longer telomere length.

Association between maternal depression symptoms and child telomere length

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

Chronic and Latent Viral Infections and Leukocyte Telomere Length across the Lifespan of Female and Male Individuals Living with or without HIV

BACKGROUND

Chronic/latent viral infections may accelerate immunological aging, particularly among people living with HIV (PLWH). We characterized chronic/latent virus infections across their lifespan and investigated their associations with leukocyte telomere length (LTL).

METHODS

Participants enrolled in the CARMA cohort study were randomly selected to include n = 15 for each decade of age between 0 and >60 y, for each sex, and each HIV status. Cytomegalovirus (CMV), Epstein-Barr virus (EBV), human herpesvirus 8 (HHV-8), herpes simplex virus 1 (HSV-1), and HSV-2 infection were determined serologically; HIV, hepatitis C (HCV), and hepatitis B (HBV) were self-reported. LTLs were measured using monochrome multiplex qPCR. Associations between the number of viruses, LTL, and sociodemographic factors were assessed using ordinal logistic and linear regression modeling.

RESULTS

The study included 187 PLWH (105 female/82 male) and 190 HIV-negative participants (105 female/84 male), ranging in age from 0.7 to 76.1 years. Living with HIV, being older, and being female were associated with harbouring a greater number of chronic/latent non-HIV viruses. Having more infections was in turn bivariately associated with a shorter LTL. In multivariable analyses, older age, living with HIV, and the female sex remained independently associated with having more infections, while having 3-4 viruses (vs. 0-2) was associated with a shorter LTL.

CONCLUSIONS

Our results suggest that persistent viral infections are more prevalent in PLWH and females, and that these may contribute to immunological aging. Whether this is associated with comorbidities later in life remains an important question.

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

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

The impact of parental and developmental stress on DNA methylation in the avian hypothalamic-pituitary-adrenal axis

The hypothalamic-pituitary-adrenal (HPA) axis coordinates an organism's response to environmental stress. The responsiveness and sensitivity of an offspring's stress response may be shaped not only by stressors encountered in their early post-natal environment but also by stressors in their parent's environment. Yet, few studies have considered how stressors encountered in both of these early life environments may function together to impact the developing HPA axis. Here, we manipulated stressors in the parental and post-natal environments in a population of house sparrows (Passer domesticus) to assess their impact on changes in DNA methylation (and corresponding gene expression) in a suite of genes within the HPA axis. We found that nestlings that experienced early life stress across both life-history periods had higher DNA methylation in a critical HPA axis gene, the glucocorticoid receptor (NR3C1). In addition, we found that the life-history stage when stress was encountered impacted some genes (HSD11B1, NR3C1 and NR3C2) differently. We also found evidence for the mitigation of parental stress by post-natal stress (in HSD11B1 and NR3C2). Finally, by assessing DNA methylation in both the brain and blood, we were able to evaluate cross-tissue patterns. While some differentially methylated regions were tissue-specific, we found cross-tissue changes in NR3C2 and NR3C1, suggesting that blood is a suitable tissue for assessing DNA methylation as a biomarker of early life stress. Our results provide a crucial first step in understanding the mechanisms by which early life stress in different life-history periods contributes to changes in the epigenome of the HPA axis.

Investigating the association of prenatal psychological adversities with mother and child telomere length and neurodevelopment

BACKGROUND

Exposure to prenatal maternal psychological adversities can negatively affect the offspring's developing brain. Shortened telomere length (TL) has been implicated as a mechanism for the transgenerational effects of maternal psychological adversities on offspring. This study aimed to determine associations between prenatal psychological stressors and distress with maternal and early life TL, and associations between maternal, newborn and child TL with neurodevelopmental outcomes at 2 years of age.

METHODS

Follow-up TL was measured in a subgroup of African mothers (n = 138) and their newborns (n = 142) and children (n = 96) at 2-years in the Drakenstein Child Health Study. Prenatal symptoms of depression, distress, intimate partner violence, posttraumatic stress-disorder and childhood trauma were measured at 27 weeks gestation. Neurodevelopment was assessed at 2 years using the Bayley Scales of Infant and Toddler Development III. TLs were measured in whole bloods from mothers and their children at 2-years, and cord bloods in newborns.

RESULTS

Maternal prenatal stressors and distress were not significantly associated with TL in mothers or their children at birth or at 2-years. Furthermore, maternal psychological measures were not associated with early-life attrition of TL. Longer TL in children at 2-years was associated (p = 0.04) with higher motor functioning.

LIMITATIONS

Limited numbers of participants and single time-point psychological measures.

CONCLUSIONS

This study is the first to provide information on the association of early life TL with prenatal psychological adversities and neurodevelopmental outcomes in a population of low-income African mothers and their children.

Early-life telomeres are influenced by environments acting at multiple temporal and spatial scales

An individual's telomere length early in life may reflect or contribute to key life-history processes sensitive to environmental variation. Yet, the relative importance of genetic and environmental factors in shaping early-life telomere length is not well understood as it requires samples collected from multiple generations with known developmental histories. We used a confirmed pedigree and conducted an animal model analysis of telomere lengths obtained from nestling house sparrows (Passer domesticus) sampled over a span of 22 years. We found significant additive genetic variation for early-life telomere length, but it comprised a small proportion (9%) of the total biological variation. Three sources of environmental variation were important: among cohorts, among-breeding attempts within years, and among nestmates. The magnitude of variation among breeding attempts and among nestmates also differed by cohort, suggesting that interactive effects of environmental factors across time or spatial scales were important, yet we were unable to identify the specific causes of these interactions. The mean amount of precipitation during the breeding season positively predicted telomere length, but neither weather during a given breeding attempt nor date in the breeding season contributed to an offspring's telomere length. At the level of individual nestlings, offspring sex, size and mass at 10 days of age also did not predict telomere length. Environmental effects appear especially important in shaping early-life telomere length in some species, and more focus on how environmental factors that interact across scales may help to explain some of the variation observed among studies.

Association between Lipids, Apolipoproteins and Telomere Length: A Mendelian Randomization Study

(1) Background: The relationship between lipids, apolipoproteins, and telomere length (TL) has been explored in previous studies; however, the causal relationship between the two remains unclear. This study aims to assess the causal relationship between lipids, apolipoproteins, and TL using the two-sample Mendelian randomization (MR) approach; (2) Methods: This study comprehensively employed both univariate MR (uvMR) and multivariate MR (mvMR) methods to genetically evaluate the associations between 21 exposures related to lipids and apolipoproteins and the outcome of TL. During the analysis process, we utilized various statistical methods, including Inverse Variance Weighting (IVW), Weighted Median, MR-Egger regression, MR-PRESSO, and outlier tests. Furthermore, to confirm the robustness of the results, we conducted several sensitivity analyses to explore potential heterogeneity; (3) Results: The uvMR analysis indicated that an increase in MUFA, MUFA/FA ratio, LDL-C, VLDL-C, total cholesterol, ApoB, and triglycerides (TG) was associated with an increase in TL. However, this relationship did not manifest in the mvMR analysis, suggesting that this association may be based on preliminary evidence; (4) Conclusions: MR analysis results suggest potential suggestive positive causal relationships between genetically predicted MUFA, MUFA/FA ratio, LDL-C, VLDL-C, total cholesterol, ApoB, and TG with TL.

Dietary nucleotides can prevent glucocorticoid-induced telomere attrition in a fast-growing wild vertebrate

Telomeres are chromosome protectors that shorten during eukaryotic cell replication and in stressful conditions. Developing individuals are susceptible to telomere erosion when their growth is fast and resources are limited. This is critical because the rate of telomere attrition in early life is linked to health and life span of adults. The metabolic telomere attrition hypothesis (MeTA) suggests that telomere dynamics can respond to biochemical signals conveying information about the organism's energetic state. Among these signals are glucocorticoids, hormones that promote catabolic processes, potentially impairing costly telomere maintenance, and nucleotides, which activate anabolic pathways through the cellular enzyme target of rapamycin (TOR), thus preventing telomere attrition. During the energetically demanding growth phase, the regulation of telomeres in response to two contrasting signals - one promoting telomere maintenance and the other attrition - provides an ideal experimental setting to test the MeTA. We studied nestlings of a rapidly developing free-living passerine, the great tit (Parus major), that either received glucocorticoids (Cort-chicks), nucleotides (Nuc-chicks) or a combination of both (NucCort-chicks), comparing these with controls (Cnt-chicks). As expected, Cort-chicks showed telomere attrition, while NucCort- and Nuc-chicks did not. NucCort-chicks was the only group showing increased expression of a proxy for TOR activation (the gene TELO2), of mitochondrial enzymes linked to ATP production (cytochrome oxidase and ATP-synthase) and a higher efficiency in aerobically producing ATP. NucCort-chicks had also a higher expression of telomere maintenance genes (shelterin protein TERF2 and telomerase TERT) and of enzymatic antioxidant genes (glutathione peroxidase and superoxide dismutase). The findings show that nucleotide availability is crucial for preventing telomere erosion during fast growth in stressful environments.

Intergenerational effects of maternal lifetime stressor exposure on offspring telomere length in Black and White women

BACKGROUND

Although maternal stressor exposure has been associated with shorter telomere length (TL) in offspring, this literature is based largely on White samples. Furthermore, timing of maternal stressors has rarely been examined. Here, we examined how maternal stressors occurring during adolescence, pregnancy, and across the lifespan related to child TL in Black and White mothers.

METHOD

Mothers (112 Black; 110 White; Mage = 39) and their youngest offspring (n = 222; Mage = 8) were part of a larger prospective cohort study, wherein mothers reported their stressors during adolescence (assessed twice during adolescence for the past year), pregnancy (assessed in midlife for most recent pregnancy), and across their lifespan (assessed in midlife). Mother and child provided saliva for TL measurement. Multiple linear regression models examined the interaction of maternal stressor exposure and race in relation to child TL, controlling for maternal TL and child gender and age. Race-stratified analyses were also conducted.

RESULTS

Neither maternal adolescence nor lifespan stressors interacted with race in relation to child TL. In contrast, greater maternal pregnancy stressors were associated with shorter child TL, but this effect was present for children of White but not Black mothers. Moreover, this effect was significant for financial but not social pregnancy stressors. Race-stratified models revealed that greater financial pregnancy stressors predicted shorter telomeres in offspring of White, but not Black mothers.

CONCLUSIONS

Race and maternal stressors interact and are related to biological aging across generations, but these effects are specific to certain races, stressors, and exposure time periods.

Effects of heat waves on telomere dynamics and parental brooding effort in nestlings of the zebra finch (Taeniopygia castanotis) transitioning from ectothermy to endothermy

Heat waves are predicted to be detrimental for organismal physiology with costs for survival that could be reflected in markers of biological state such as telomeres. Changes in early life telomere dynamics driven by thermal stress are of particular interest during the early post-natal stages of altricial birds because nestlings quickly shift from being ectothermic to endothermic after hatching. Telomeres of ectothermic and endothermic organisms respond differently to environmental temperature, but few investigations within species that transition from ectothermy to endothermy are available. Also, ambient temperature influences parental brooding behaviour, which will alter the temperature experienced by offspring and thereby, potentially, their telomeres. We exposed zebra finch nestlings to experimental heat waves and compared their telomere dynamics to that of a control group at 5, 12 and 80 days of age that encapsulate the transition from the ectothermic to the endothermic thermoregulatory stage; we also recorded parental brooding, offspring sex, mass, growth rates, brood size and hatch order. Nestling mass showed an inverse relationship with telomere length, and nestlings exposed to heat waves showed lower telomere attrition during their first 12 days of life (ectothermic stage) compared to controls. Additionally, parents of heated broods reduced the time they spent brooding offspring (at 5 days old) compared to controls. Our results indicate that the effect of heat waves on telomere dynamics likely varies depending on age and thermoregulatory stage of the offspring in combination with parental brooding behaviour during growth.

Protocol for the COVID-19 Wellbeing and Stress Study: a longitudinal study of parent distress, biological stress and child biopsychosocial development during the pandemic and beyond

INTRODUCTION

The COVID-19 pandemic has had a unique impact on the mental health and well-being of pregnant individuals and parents of young children. However, the impact of COVID-19-related stress during pregnancy on early child biopsychosocial development, remains unclear. The COVID-19 Wellbeing and Stress Study will: (1) investigate the impact of different forms of prenatal stress experienced during the pandemic (including objective hardship, perceived psychological distress and biological stress) on child stress biology, (2) examine the association between child stress biology and child developmental outcomes, (3) determine whether child stress biology acts as a mechanism linking prenatal stress to adverse child developmental outcomes and (4) assess whether gestational age at the onset of the COVID-19 pandemic or child sex, moderate these associations.

METHODS AND ANALYSES

The COVID-19 Wellbeing and Stress Study is a prospective longitudinal study, consisting of six time points, spanning from pregnancy to 3 years postpartum. The study began in June 2020, consisting of 304 pregnant people from Ontario, Canada. This multimethod study is composed of questionnaires, biological samples, behavioural observations and developmental assessments ETHICS AND DISSEMINATION: This study was approved by the Hamilton Integrated Research Ethics Board (#11034) and the Mount Saint Vincent University Research Ethics Board (#2020-187, #2021-075, #2022-008). Findings will be disseminated through peer-reviewed presentations and publications, community presentations, and electronic forums (social media, newsletters and website postings).

Pathomechanisms of Prenatally Programmed Adult Diseases

Based on epidemiological observations Barker et al. put forward the hypothesis/concept that an adverse intrauterine environment (involving an insufficient nutrient supply, chronic hypoxia, stress, and toxic substances) is an important risk factor for the development of chronic diseases later in life. The fetus responds to the unfavorable environment with adaptive reactions, which ensure survival in the short run, but at the expense of initiating pathological processes leading to adult diseases. In this review, the major mechanisms (including telomere dysfunction, epigenetic modifications, and cardiovascular-renal-endocrine-metabolic reactions) will be outlined, with a particular emphasis on the role of oxidative stress in the fetal origin of adult diseases.

Maternal racism experience and cultural identity in relation to offspring telomere length

Racism is a determinant of individual and offspring health. Accelerated telomere shortening, an indicator of cellular aging, is a potential mechanism through which parental experience of racism could affect offspring. Here we longitudinally evaluated the relationship between maternal lifetime experience of an ethnically-motivated verbal or physical attack, as reported in pregnancy, with offspring telomere length in 4.5-year-old children. We also explored the potential association between positive feelings about one's culture and offspring telomere length. Data come from a nationally representative, multi-ethnic birth cohort in Aotearoa New Zealand (NZ) (Māori N = 417, Pacific N = 364, Asian N = 381). In models adjusting for covariates, including socioeconomic status and health status, Māori mothers who experienced an ethnically-motivated physical attack had children with significantly shorter telomere length than children of Māori mothers who did not report an attack (B = - 0.20, p = 0.01). Conversely, Māori mothers who had positive feelings about their culture had offspring with significantly longer telomeres (B = 0.25, p = 0.02). Our results suggest that ethnicity-based health inequities are shaped by racism, with impacts for clinical care and policy. Future research should also evaluate the potential protective effects of positive cultural identity.

Associations Between Children's Telomere Length, Parental Intrusiveness, and the Development of Early Externalizing Behaviors

Shorter telomeres mark cellular aging and are linked to chronic stress exposure as well as negative physical and psychological outcomes. However, it is unclear whether telomere length mediates associations between early stress exposure and later externalizing problems, or whether boys and girls differ in pathways to these concerns. We therefore examined associations between telomere length, early stress via negative caregiving, and children's externalizing symptom development over time in 409 three-year-old children and their parents. Telomere length mediated the association between early parental intrusiveness and later rule-breaking behavior; however, this association was moderated by children's biological sex such that parent intrusiveness was related only to boys' rule-breaking. Findings support the notion that children's telomere length may mark individual differences in responses to negative early caregiving, and highlight a potential mechanism contributing to the development of rule-breaking problems in boys.

Stressful life events and accelerated biological aging over time in youths

Experiencing adversity in childhood and adolescence, including stressful life events (SLEs), may accelerate the pace of development, leading to adverse mental and physical health. However, most research on adverse early experiences and biological aging (BA) in youths relies on cross-sectional designs. In 171 youths followed for approximately 2 years, we examined if SLEs over follow-up predicted rate of change in two BA metrics: epigenetic age and Tanner stage. We also investigated if rate of change in BA was associated with changes in depressive symptoms over time. Youths aged 8-16 years at baseline self-reported Tanner stage and depressive symptoms at baseline and follow-up and provided saliva samples for DNA at both assessments. Horvath epigenetic age estimates were derived from DNA methylation data measured with the Illumina EPIC array. At follow-up, contextual threat interviews were administered to youths and caregivers to assess youths' experiences of past-year SLEs. Interviews were objectively coded by an independent rating team to generate a SLE impact score, reflecting the severity of all SLEs occurring over the prior year. Rate of change in BA metrics was operationalized as change in epigenetic age or Tanner stage as a function of time between assessments. Higher objective SLE impact scores over follow-up were related to a greater rate of change in epigenetic age (β = 0.21, p = .043). Additionally, among youths with lower-but not higher-Tanner stage at baseline, there was a positive association of SLE impact scores with rate of change in Tanner stage (Baseline Tanner Stage × SLE Impact Score interaction: β = - 0.21, p = .011). A greater rate of change in epigenetic age was also associated with higher depressive symptom levels at follow-up, adjusting for baseline symptoms (β = 0.15, p = .043). Associations with epigenetic age were similar, although slightly attenuated, when adjusting for epithelial (buccal) cell proportions. Whereas much research in youths has focused on severe experiences of early adversity, we demonstrate that more commonly experienced SLEs during adolescence may also contribute to accelerated BA. Further research is needed to understand the long-term consequences of changes in BA metrics for health.

The association between household biomass fuel use and leukocyte telomere length among toddlers in Bhaktapur, Nepal

BACKGROUND

Biomass fuels are still in use for cooking by many households in resource poor countries such as Nepal and is a major source of household air pollution (HAP). Chronic exposure to HAP has been shown to be associated with shorter telomere length in adults.

OBJECTIVES

To measure the association between exposure related to household biomass fuel in infancy and leukocyte telomere length (LTL) at 18-23 months of age among 497 children from Bhaktapur, Nepal.

METHODS

In a prospective cohort study design, we have collected information on household cooking fuel use and several clinical, anthropometric, demographic, and socioeconomic variables. We estimated the association between biomass fuel use and the relative LTL in multiple linear regression models.

RESULTS

Most of the families (78%) reported liquified petroleum gas (LPG) as the primary cooking fuel, and 18.7% used biomass. The mean relative (SD) LTL was 1.03 (0.19). Children living in households using biomass fuel had on average 0.09 (95% CI: 0.05 to 0.13) units shorter LTL than children in households with no biomass fuel use. The observed association was unaltered after adjusting for relevant confounders. The association between LTL and biomass use was strongest among children from households with ≤2 rooms and without separate kitchen.

SIGNIFICANCE

Exposure to biomass fuel use in early life might have consequences for longevity, and risk of chronic illnesses reflected in shortening of the telomeres. Our findings support the ongoing effort to reduce exposure to biomass fuel in low-resource settings.

IMPACT STATEMENTS

Biomass for cooking is a leading source of household air pollution in low and middle-income countries, contributing to many chronic diseases and premature deaths. Chronic exposure to biomass fuel through oxidative stress and inflammation has been associated with a shortening of the telomeres, a "biological marker" of longevity. This prospective cohort study describes the association between household biomass fuel use and leukocyte telomere length among 497 toddlers. Leukocyte telomere length was significantly shorter among children living in households with biomass fuel than in children from homes where mainly LPG was used for cooking.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov: NCT02272842, registered October 21, 2014, Universal Trial Number: U1111-1161-5187 (September 8, 2014).

Prenatal stress modulates HPA axis homeostasis of offspring through dentate TERT independently of glucocorticoids receptor

In response to stressful events, the hypothalamic-pituitary-adrenal (HPA) axis is activated, and consequently glucocorticoids are released by the adrenal gland into the blood circulation. A large body of research has illustrated that excessive glucocorticoids in the hippocampus exerts negative feedback regulation of the HPA axis through glucocorticoid receptor (GR), which is critical for the homeostasis of the HPA axis. Maternal prenatal stress causes dysfunction of the HPA axis feedback mechanism in their offspring in adulthood. Here we report that telomerase reverse transcriptase (TERT) gene knockout causes hyperactivity of the HPA axis without hippocampal GR deficiency. We found that the level of TERT in the dentate gyrus (DG) of the hippocampus during the developmental stage determines the responses of the HPA axis to stressful events in adulthood through modulating the excitability of the dentate granular cells (DGCs) rather than the expression of GR. Our study also suggests that the prenatal high level of glucocorticoids exposure-induced hypomethylation at Chr13:73764526 in the first exon of mouse Tert gene accounted for TERT deficiency in the DG and HPA axis abnormality in the adult offspring. This study reveals a novel GR-independent mechanism underlying prenatal stress-associated HPA axis impairment, providing a new angle for understanding the mechanisms for maintaining HPA axis homeostasis.

Egg corticosterone can stimulate telomerase activity and promote longer telomeres during embryo development

It is often assumed that the transfer of maternal glucocorticoids (GCs; e.g., corticosterone or cortisol) to offspring is an inevitable cost associated with adverse or stressful conditions experienced by mothers. However, recent evidence indicates that maternal GCs may adaptively programme particular physiological and molecular pathways during development to enhance offspring fitness. In this context, an important mechanism through which maternal GCs may lastingly affect offspring phenotypic quality and survival is via effects on embryo telomerase activity and so on offspring postnatal telomere length. Here, using a field experimental design for which we manipulated the corticosterone content in yellow-legged gull (Larus michahellis) eggs, we show that embryos from corticosterone-injected eggs not only had a higher telomerase activity but also longer telomeres just after hatching. A complementary analysis further revealed that gull hatchlings with longer telomeres had a higher survival probability during the period when most of the chick mortality occurs. Given the important role that telomere length and its restoring mechanisms have on ageing trajectories and disease risk, our findings provide a new mechanistic link by which mothers may presumably shape offspring life-history trajectories and phenotype.

Telomere length is highly heritable and independent of growth rate manipulated by temperature in field crickets

Many organisms are capable of growing faster than they do. Restrained growth rate has functionally been explained by negative effects on lifespan of accelerated growth. However, the underlying mechanisms remain elusive. Telomere attrition has been proposed as a causal agent and has been mostly studied in endothermic vertebrates. We established that telomeres exist as chromosomal-ends in a model insect, the field cricket Gryllus campestris, using terminal restriction fragment and Bal 31 methods. Telomeres comprised TTAGGn repeats of 38 kb on average, more than four times longer than the telomeres of human infants. Bal 31 assays confirmed that telomeric repeats were located at the chromosome-ends. We tested whether rapid growth between day 1, day 65, day 85, and day 125 is achieved at the expense of telomere length by comparing nymphs reared at 23°C with their siblings reared at 28°C, which grew three times faster in the initial 65 days. Surprisingly, neither temperature treatment nor age affected average telomere length. Concomitantly, the broad sense heritability of telomere length was remarkably high at ~100%. Despite high heritability, the evolvability (a mean-standardized measure of genetic variance) was low relative to that of body mass. We discuss our findings in the context of telomere evolution. Some important features of vertebrate telomere biology are evident in an insect species dating back to the Triassic. The apparent lack of an effect of growth rate on telomere length is puzzling, suggesting strong telomere length maintenance during the growth phase. Whether such maintenance of telomere length is adaptive remains elusive and requires further study investigating the links with fitness in the wild.

Parental Genetics Communicate with Intrauterine Environment to Reprogram Newborn Telomeres and Immunity

Telomeres, markers for cellular senescence, have been found substantially influenced by parental inheritance. It is well known that genomic stability is preserved by the DNA repair mechanism through telomerase. This study aimed to determine the association between parents−newborn telomere length (TL) and telomerase gene (TERT), highlighting DNA repair combined with TL/TERT polymorphism and immunosenescence of the triad. The mother−father−newborn triad blood samples (n = 312) were collected from Ziauddin Hospitals, Pakistan, between September 2021 and June 2022. The telomere length (T/S ratio) was quantified by qPCR, polymorphism was identified by Sanger sequencing, and immunosenescence by flow cytometry. The linear regression was applied to TL and gene association. The newborns had longest TL (2.51 ± 2.87) and strong positive association (R = 0.25, p ≤ 0.0001) (transgenerational health effects) with mothers’ TL (1.6 ± 2.00). Maternal demographics—socioeconomic status, education, and occupation—showed significant effects on TL of newborns (p < 0.015, 0.034, 0.04, respectively). The TERT risk genotype CC (rs2736100) was predominant in the triad (0.6, 0.5, 0.65, respectively) with a strong positive association with newborn TL (β = 2.91, <0.0011). Further analysis highlighted the expression of KLRG 1+ in T-cells with shorter TL but less frequent among newborns. The study concludes that TERT, parental TL, antenatal maternal health, and immunity have a significantly positive effect on the repair of newborn TL.

Diurnal cortisol variation during pregnancy in Turkish origin and non-migrant women in a German birth cohort study

BACKGROUND

Immigrants from Turkey experience health disadvantages relative to non-immigrant populations in Germany that are manifest from the earliest stages of the lifespan onwards and are perpetuated across generations. Chronic stress and perturbations of stress-responsive physiological systems, including the hypothalamus-pituitary-adrenal (HPA)-axis, are believed to in part mediate this relationship. Cortisol plays an important role in the association between maternal stress during pregnancy and many pregnancy-, birth- and offspring-related outcomes. We therefore examined whether maternal migrant background is associated with diurnal cortisol variation during pregnancy.

METHODS

109 pregnant women (incl. n = 32 Turkish origin women) that participated in a multi-site prospective cohort study in Germany collected saliva samples across the day on two consecutive days around 24 and 32 weeks gestation. Hierarchical linear models were applied to quantify associations between migrant background and diurnal cortisol variation across pregnancy.

RESULTS

Women of Turkish origin exhibited a significantly lower cortisol awakening response (CAR) and a flatter diurnal cortisol slope (DCS) compared to non-migrant women after adjusting for household income. These relationships between migrant status and diurnal cortisol variation were mainly driven by 2nd generation migrants.

DISCUSSION

A potential HPA axis dysregulation of Turkish-origin pregnant women may contribute to the intergenerational transmission of health disadvantages in this group.

Wildfire Smoke Exposure during Pregnancy: A Review of Potential Mechanisms of Placental Toxicity, Impact on Obstetric Outcomes, and Strategies to Reduce Exposure

Climate change is accelerating the intensity and frequency of wildfires globally. Understanding how wildfire smoke (WS) may lead to adverse pregnancy outcomes and alterations in placental function via biological mechanisms is critical to mitigate the harms of exposure. We aim to review the literature surrounding WS, placental biology, biological mechanisms underlying adverse pregnancy outcomes as well as interventions and strategies to avoid WS exposure in pregnancy. This review includes epidemiologic and experimental laboratory-based studies of WS, air pollution, particulate matter (PM), and other chemicals related to combustion in relation to obstetric outcomes and placental biology. We summarized the available clinical, animal, and placental studies with WS and other combustion products such as tobacco, diesel, and wood smoke. Additionally, we reviewed current recommendations for prevention of WS exposure. We found that there is limited data specific to WS; however, studies on air pollution and other combustion sources suggest a link to inflammation, oxidative stress, endocrine disruption, DNA damage, telomere shortening, epigenetic changes, as well as metabolic, vascular, and endothelial dysregulation in the maternal-fetal unit. These alterations in placental biology contribute to adverse obstetric outcomes that disproportionally affect the most vulnerable. Limiting time outdoors, wearing N95 respirator face masks and using high quality indoor air filters during wildfire events reduces exposure to related environmental exposures and may mitigate morbidities attributable to WS.

Perinatal and early childhood biomarkers of psychosocial stress and adverse experiences

The human brain develops through a complex interplay of genetic and environmental influences. During critical periods of development, experiences shape brain architecture, often with long-lasting effects. If experiences are adverse, the effects may include the risk of mental and physical disease, whereas positive environments may increase the likelihood of healthy outcomes. Understanding how psychosocial stress and adverse experiences are embedded in biological systems and how we can identify markers of risk may lead to discovering new approaches to improve patient care and outcomes. Biomarkers can be used to identify specific intervention targets and at-risk children early when physiological system malleability increases the likelihood of intervention success. However, identifying reliable biomarkers has been challenging, particularly in the perinatal period and the first years of life, including in preterm infants. This review explores the landscape of psychosocial stress and adverse experience biomarkers. We highlight potential benefits and challenges of identifying risk clinically and different sub-signatures of stress, and in their ability to inform targeted interventions. Finally, we propose that the combination of preterm birth and adversity amplifies the risk for abnormal development and calls for a focus on this group of infants within the field of psychosocial stress and adverse experience biomarkers. IMPACT: Reviews the landscape of biomarkers of psychosocial stress and adverse experiences in the perinatal period and early childhood and highlights the potential benefits and challenges of their clinical utility in identifying risk status in children, and in developing targeted interventions. Explores associations between psychosocial stress and adverse experiences in childhood with prematurity and identifies potential areas of assessment and intervention to improve outcomes in this at-risk group.

Stressors interact across generations to influence offspring telomeres and survival

Parental stress often has long-term consequences for offspring. However, the mechanisms underlying these effects and how they are shaped by conditions offspring subsequently experience are poorly understood. Telomeres, which often shorten in response to stress and predict longevity, may contribute to, and/or reflect these cross-generational effects. Traditionally, parental stress is expected to have negative effects on offspring telomeres, but experimental studies in captive animals suggest that these effects may depend on the subsequent conditions that offspring experience. Yet, the degree to which parental stress influences and interacts with stress experienced by offspring to affect offspring telomeres and survival in free-living organisms is unknown. To assess this, we experimentally manipulated the stress exposure of free-living parent and offspring house sparrows (Passer domesticus). We found a weak, initial, negative effect of parental stress on offspring telomeres, but this effect was no longer evident at the end of post-natal development. Instead, the effects of parental stress depended on the natural sources of stress that offspring experienced during post-natal development whereby some outcomes were improved under more stressful rearing conditions. Thus, the effects of parental stress on offspring telomeres and survival are context-dependent and may involve compensatory mechanisms of potential benefit under some circumstances.

Chromosomal and environmental contributions to sex differences in the vulnerability to neurological and neuropsychiatric disorders: Implications for therapeutic interventions

Neurological and neuropsychiatric disorders affect men and women differently. Multiple sclerosis, Alzheimer's disease, anxiety disorders, depression, meningiomas and late-onset schizophrenia affect women more frequently than men. By contrast, Parkinson's disease, autism spectrum condition, attention-deficit hyperactivity disorder, Tourette's syndrome, amyotrophic lateral sclerosis and early-onset schizophrenia are more prevalent in men. Women have been historically under-recruited or excluded from clinical trials, and most basic research uses male rodent cells or animals as disease models, rarely studying both sexes and factoring sex as a potential source of variation, resulting in a poor understanding of the underlying biological reasons for sex and gender differences in the development of such diseases. Putative pathophysiological contributors include hormones and epigenetics regulators but additional biological and non-biological influences may be at play. We review here the evidence for the underpinning role of the sex chromosome complement, X chromosome inactivation, and environmental and epigenetic regulators in sex differences in the vulnerability to brain disease. We conclude that there is a pressing need for a better understanding of the genetic, epigenetic and environmental mechanisms sustaining sex differences in such diseases, which is critical for developing a precision medicine approach based on sex-tailored prevention and treatment.

Effect of Omega-3 Fatty Acids on Telomeres-Are They the Elixir of Youth?

Telomeres are complexes consisting of tandem repeat DNA combined with associated proteins that play a key role in protecting the ends of chromosomes and maintaining genome stability. They are considered a biological clock, as they shorten in parallel with aging. Furthermore, short telomeres are associated with several age-related diseases. However, the variability in telomere shortening independent of chronological age suggests that it is a modifiable factor. In fact, it is regulated inter alia by genetic damage, cell division, aging, oxidative stress, and inflammation. A key question remains: how can we prevent accelerated telomere attrition and subsequent premature replicative senescence? A number of studies have explored the possible impact of omega-3 fatty acids on telomere shortening. This review summarizes published cross-sectional studies, randomized controlled trials, and rodent studies investigating the role of omega-3 fatty acids in telomere biology. It also covers a broad overview of the mechanism, currently favored in the field, that explains the impact of omega-3 fatty acids on telomeres—the food compound’s ability to modulate oxidative stress and inflammation. Although the results of the studies performed to date are not consistent, the vast majority indicate a beneficial effect of omega-3 fatty acids on telomere length.

Effects of the social environment on vertebrate fitness and health in nature: Moving beyond the stress axis

Social interactions are a ubiquitous feature of the lives of vertebrate species. These may be cooperative or competitive, and shape the dynamics of social systems, with profound effects on individual behavior, physiology, fitness, and health. On one hand, a wealth of studies on humans, laboratory animal models, and captive species have focused on understanding the relationships between social interactions and individual health within the context of disease and pathology. On the other, ecological studies are attempting an understanding of how social interactions shape individual phenotypes in the wild, and the consequences this entails in terms of adaptation. Whereas numerous studies in wild vertebrates have focused on the relationships between social environments and the stress axis, much remains to be done in understanding how socially-related activation of the stress axis coordinates other key physiological functions related to health. Here, we review the state of our current knowledge on the effects that social interactions may have on other markers of vertebrate fitness and health. Building upon complementary findings from the biomedical and ecological fields, we identify 6 key physiological functions (cellular metabolism, oxidative stress, cellular senescence, immunity, brain function, and the regulation of biological rhythms) which are intimately related to the stress axis, and likely directly affected by social interactions. Our goal is a holistic understanding of how social environments affect vertebrate fitness and health in the wild. Whereas both social interactions and social environments are recognized as important sources of phenotypic variation, their consequences on vertebrate fitness, and the adaptive nature of social-stress-induced phenotypes, remain unclear. Social flexibility, or the ability of an animal to change its social behavior with resulting changes in social systems in response to fluctuating environments, has emerged as a critical underlying factor that may buffer the beneficial and detrimental effects of social environments on vertebrate fitness and health.

Causes and consequences of variation in early-life telomere length in a bird metapopulation

Environmental conditions during early-life development can have lasting effects shaping individual heterogeneity in fitness and fitness-related traits. The length of telomeres, the DNA sequences protecting chromosome ends, may be affected by early-life conditions, and telomere length (TL) has been associated with individual performance within some wild animal populations. Thus, knowledge of the mechanisms that generate variation in TL, and the relationship between TL and fitness, is important in understanding the role of telomeres in ecology and life-history evolution. Here, we investigate how environmental conditions and morphological traits are associated with early-life blood TL and if TL predicts natal dispersal probability or components of fitness in 2746 wild house sparrow (Passer domesticus) nestlings from two populations sampled across 20 years (1994-2013). We retrieved weather data and we monitored population fluctuations, individual survival, and reproductive output using field observations and genetic pedigrees. We found a negative effect of population density on TL, but only in one of the populations. There was a curvilinear association between TL and the maximum daily North Atlantic Oscillation index during incubation, suggesting that there are optimal weather conditions that result in the longest TL. Dispersers tended to have shorter telomeres than non-dispersers. TL did not predict survival, but we found a tendency for individuals with short telomeres to have higher annual reproductive success. Our study showed how early-life TL is shaped by effects of growth, weather conditions, and population density, supporting that environmental stressors negatively affect TL in wild populations. In addition, shorter telomeres may be associated with a faster pace-of-life, as individuals with higher dispersal rates and annual reproduction tended to have shorter early-life TL.

Telomeres, aging and reproduction

PURPOSE OF REVIEW

Women's fertility decay starts at the mid 30 s. However, the current delay of childbearing leads to ovarian aging and the need of assisted reproduction technologies (ART). Telomere biology is one of the main pathways involved in organismal aging. Thus, this review will focus on the knowledge acquired during the last 2 years about the telomere pathway and its influence on female fertility and the consequences for the newborn.

RECENT FINDINGS

New research on telomere biology reaffirms the relationship of telomere attrition and female infertility. Shorter maternal telomeres, which could be aggravated by external factors, underly premature ovarian aging and other complications including preeclampsia, preterm birth and idiopathic pregnancy loss. Finally, the telomere length of the fetus or the newborn is also affected by external factors, such as stress and nutrition.

SUMMARY

Recent evidence shows that telomeres are implicated in most processes related to female fertility, embryo development and the newborn's health. Thus, telomere length and telomerase activity may be good biomarkers for early detection of ovarian and pregnancy failures, opening the possibility to use telomere therapies to try to solve the infertility situation.

Acculturative stress, telomere length, and postpartum depression in Latinx mothers

Latinx mothers in the United States are highly vulnerable to psychosocial stressors, including discrimination and acculturative stress, which increase maternal health risks. Previous work in Latinx mothers indicates that prenatal discrimination influences epigenetic immune markers that may increase risk for postpartum depression. Discrimination and acculturative stress have also been linked to cellular aging, including telomere degradation, in Hispanic populations broadly, but not in this particularly vulnerable population. The present work addressed this gap in a sample of 150 Latinx mothers living in the United States (mean age 27.6 years). Psychosocial measures (including discrimination, stress, and mental health) and blood were collected at 24-32 weeks gestation. Psychosocial measures were re-evaluated at 4-6 weeks postpartum. First, we examined the relationship between maternal prenatal cultural stress (i.e., discrimination and acculturative stress) and telomere length (TL). Second, we tested whether TL predicted postpartum depression. Acculturative stress - but not discrimination - predicted shorter TL, especially among participants with high methylation of the FOXP3 promoter region. Further, shorter telomere measures during pregnancy predicted greater postpartum depression symptom severity. TL was not related to any sociodemographic characteristics such as age, income, country of origin, or years in the United States. These results highlight the uniquely impactful role of acculturative stress on Latinx maternal health and the potential interactive role of telomere length and epigenetic immune alterations in risk for maternal mental health concerns.

Severe maternal hardships are associated with food insecurity among low-income/lower-income women during pregnancy: results from the 2012–2014 California maternal infant health assessment

Background

Assess the associations between ten severe maternal hardships and food insecurity experienced during pregnancy.

Methods

Data on 14,274 low-income/lower-income women (below 400% of the income to federal poverty guideline ratio) from the statewide-representative 2010–2012 California Maternal and Infant Health Assessment were used to estimate food security status prevalence. Prevalence of severe maternal hardships by food security status was estimated. Multinomial logistic regression was used to assess the associations between severe maternal hardship and food security status, adjusting for sociodemographic characteristics.

Results

Food insecurity was common among low- and lower-income pregnant women in California; 23.4% food insecure and an additional 11.5% marginally secure. In adjusted analysis, nine of ten hardships were associated with food security status. Only the respondent or someone close to the respondent having a problem with alcohol or drugs was not associated with food security status after adjusting for socioeconomic factors. Husband/partner losing a job, depressive symptoms, not having practical support and intimate partner violence were consistently associated with marginal, low and very low food security status. Each additional severe maternal hardship a woman experienced during pregnancy was associated with a 36% greater risk of reporting marginal food security (Relative Risk Ratio 1.36, 95% CI: 1.27, 1.47), 54% for low food security (Relative Risk Ratio 1.54, 95% CI: 1.44, 1.64), and 99% for very low food security (Relative Risk Ratio 1.99, 95% CI: 1.83, 2.15).

Conclusions

Food security status was strongly linked with several maternal hardships that could jeopardize maternal and/or infant health.

Services—including prenatal care and nutritional assistance—for a large proportion of pregnant women should address a wide range of serious unmet social needs including food insecurity.

Parental Separation and Semen Quality in Young Men: A Population-Based Cohort Study

Purpose

Parental separation may be a stressful life event with the potential to influence hormonal regulation of offspring reproductive health and thereby affect semen quality in young men. We aimed to study the association between parental separation in pregnancy or in childhood and semen quality in young men and to study whether the timing of parental separation in childhood was important.

Patients and Methods

We conducted a follow-up study of 1058 young men born 1998–2000 from the Fetal Programming of Semen Quality (FEPOS) cohort nested within the Danish National Birth Cohort. Data on parental separation were obtained longitudinal by self-report. Parental separation in pregnancy was dichotomized, and parental separation in childhood was both dichotomized and categorized according to the timing of parental separation (from birth, from early childhood (0–5 years), and from late childhood (6–10 years)). Semen volume, concentration, total sperm count, motility, morphology, and testes volume were analysed using multivariable negative binomial regression models.

Results

Parental separation in pregnancy was not associated with semen quality. The association between parental separation in childhood and semen quality differed with the timing of parental separation. Parental separation from birth was associated with higher semen volume of 25%, 95% CI (−5; 64); higher total sperm count of 62%, 95% CI (−6; 179); and higher proportion of morphologically normal spermatozoa of 59%, 95% CI (20; 111). Parental separation in early childhood was associated with lower semen volume of −14%, 95% CI (−24; −3); lower concentration of −15%, 95% CI (−28; 1); lower total sperm count of −17%, 95% CI (−32; 2) and lower testes volume of −11%, 95% CI (−18; −3).

Conclusion

The timing of parental separation was important, and parental separation from birth was associated with higher semen quality, and parental separation in early childhood was associated with lower semen quality.

Prenatal exposure to maternal psychological distress and telomere length in childhood

Telomere length (TL) is a biological marker of cellular aging, and shorter TL in adulthood is associated with increased morbidity and mortality risk. It is likely that these differences in TL are established long before adulthood, and there is growing evidence that TL can reflect prenatal experiences. Although maternal prenatal distress predicts newborn TL, it is unknown whether the relation between prenatal exposure to maternal distress and child TL persists through childhood. The purpose of the current longitudinal, prospective study is to examine the relation between prenatal exposure to maternal distress (perceived stress, depressive symptoms, pregnancy-related anxiety) and TL in childhood. Participants included 102 children (54 girls) and their mothers. Mothers' distress was assessed five times during pregnancy, at 12 weeks postpartum, and at the time of child telomere measurement between 6 and 16 years of age. Maternal distress during pregnancy predicted shorter offspring TL in childhood, even after accounting for postnatal exposure to maternal distress and other covariates. These findings indicate that maternal mental health predicts offspring TL biology later in childhood than previously observed. This study bolsters claims that telomere biology is subject to fetal programming and highlights the importance of supporting maternal mental health during pregnancy.

Diabetic pregnancy as a novel risk factor for cardiac dysfunction in the offspring-the heart as a target for fetal programming in rats

AIMS/HYPOTHESIS

The impact of diabetic pregnancy has been investigated extensively regarding offspring metabolism; however, little is known about the influence on the heart. We aimed to characterise the effects of a diabetic pregnancy on male adult offspring cardiac health after feeding a high-fat diet in an established transgenic rat model.

METHODS

We applied our rat model for maternal type 2 diabetes characterised by maternal insulin resistance with hyperglycaemia and hyperinsulinaemia. Diabetes was induced preconceptionally via doxycycline-induced knock down of the insulin receptor in transgenic rats. Male wild-type offspring of diabetic and normoglycaemic pregnancies were raised by foster mothers, followed up into adulthood and subgroups were challenged by a high-fat diet. Cardiac phenotype was assessed by innovative speckle tracking echocardiography, circulating factors, immunohistochemistry and gene expression in the heart.

RESULTS

When feeding normal chow, we did not observe differences in cardiac function, gene expression and plasma brain natriuretic peptide between adult diabetic or normoglycaemic offspring. Interestingly, when being fed a high-fat diet, adult offspring of diabetic pregnancy demonstrated decreased global longitudinal (-14.82 ± 0.59 vs -16.60 ± 0.48%) and circumferential strain (-23.40 ± 0.57 vs -26.74 ± 0.34%), increased relative wall thickness (0.53 ± 0.06 vs 0.37 ± 0.02), altered cardiac gene expression, enlarged cardiomyocytes (106.60 ± 4.14 vs 87.94 ± 1.67 μm), an accumulation of immune cells in the heart (10.27 ± 0.30 vs 6.48 ± 0.48 per fov) and higher plasma brain natriuretic peptide levels (0.50 ± 0.12 vs 0.12 ± 0.03 ng/ml) compared with normoglycaemic offspring on a high-fat diet. Blood pressure, urinary albumin, blood glucose and body weight were unaltered between groups on a high-fat diet.

CONCLUSIONS/INTERPRETATION

Diabetic pregnancy in rats induces cardiac dysfunction, left ventricular hypertrophy and altered proinflammatory status in adult offspring only after a high-fat diet. A diabetic pregnancy itself was not sufficient to impair myocardial function and gene expression in male offspring later in life. This suggests that a postnatal high-fat diet is important for the development of cardiac dysfunction in rat offspring after diabetic pregnancy. Our data provide evidence that a diabetic pregnancy is a novel cardiac risk factor that becomes relevant when other challenges, such as a high-fat diet, are present.

Prenatal exposure to triclosan induced brain telomere shortening in a wild bird species

Exposure to the antimicrobial agent Triclosan (TCS) induces oxidative stress in diverse organisms, including birds. However, whether TCS-induced oxidative stress effectively translates into detrimental effects is still unclear. The present study examined whether prenatal TCS exposure induces oxidative stress and telomere shortening in the brain and the liver of near-term embryos of the yellow-legged gull (Larus michahellis). Prenatal TCS exposure caused a significant overproduction of reactive oxygen species (ROS) in the brain, but no oxidative damage occurred. Telomeres of TCS-exposed embryos had brain telomeres 30 % shorter compared to controls, probably because the relatively modest antioxidant defenses of this organ during prenatal development cannot counteract the impact of the TCS-induced ROS. No telomere shortening was observed in the liver. Our results demonstrated that prenatal exposure to TCS in wild bird species can modulate the oxidative status and induce telomere shortening in the brain of the yellow-legged gull embryos.

Research Review: Developmental origins of depression - a systematic review and meta-analysis

BACKGROUND

Many observational studies have found a direct association between adverse in utero, perinatal and postnatal exposures and offspring's depression. These findings are consistent with the 'developmental origins of disease hypothesis'. But no review has comprehensively summarized the roles of these exposures. This review aims to systematically scrutinize the strength of associations between individual prenatal, perinatal, and postnatal exposures and subsequent depression in offspring.

METHODS

We conducted a systematic review and meta-analysis to synthesize the literature from the EMBASE, HealthStar, PsychoInfo, and Medline databases since their inception to September 1, 2019. English language articles on population-based prospective cohort studies examining the associations between in utero, perinatal, and postnatal exposures and offspring's depression were searched. Random-effects models were used to calculate pooled estimates, and heterogeneity and sensitivity tests were conducted to explore potential confounders in the relationships of depression and early-life factors. Qualitative analysis was also conducted.

RESULTS

Sixty-four prospective cohort studies with 28 exposures studied in the relationships to offspring's depression met inclusion criteria. The meta-analysis found 12 prenatal, perinatal, and postnatal characteristics were associated with an increased risk of depression in offspring: low birth weight, premature birth, small gestational age, maternal education, socioeconomic status, having younger parents (<20 years), having older parents (≥35 years), maternal smoking, paternal smoking, maternal stress, maternal anxiety, and prenatal depression. Heterogeneity and sensitivity tests supported the findings. By and large, study characteristics had no effects on conclusions. Qualitative analyses generally supported the findings of meta-analysis and reported on additional risk factors.

CONCLUSIONS

This review provides a robust and comprehensive overview of the lasting psychopathological effects of in utero, perinatal, and postnatal exposures. The findings highlight the need for clinical and public health interventions focusing on the identified risk factors. Large prospective cohort studies are warranted to investigate the combined effects of multiple co-existing early-life exposures.

Symptoms of Prenatal Depression Associated with Shorter Telomeres in Female Placenta

BACKGROUND

Depression is a common mood disorder during pregnancy impacting one in every seven women. Children exposed to prenatal depression are more likely to be born at a low birth weight and develop chronic diseases later in life. A proposed hypothesis for this relationship between early exposure to adversity and poor outcomes is accelerated aging. Telomere length has been used as a biomarker of cellular aging. We used high-resolution telomere length analysis to examine the relationship between placental telomere length distributions and maternal mood symptoms in pregnancy.

METHODS

This study utilised samples from the longitudinal Grown in Wales (GiW) study. Women participating in this study were recruited at their presurgical appointment prior to a term elective caesarean section (ELCS). Women completed the Edinburgh Postnatal Depression Scale (EPDS) and trait subscale of the State-Trait Anxiety Inventory (STAI). Telomere length distributions were generated using single telomere length analysis (STELA) in 109 term placenta (37-42 weeks). Multiple linear regression was performed to examine the relationship between maternally reported symptoms of depression and anxiety at term and mean placental telomere length.

RESULTS

Prenatal depression symptoms were significantly negatively associated with XpYp telomere length in female placenta (B = -0.098, p = 0.026, 95% CI -0.184, -0.012). There was no association between maternal depression symptoms and telomere length in male placenta (B = 0.022, p = 0.586, 95% CI -0.059, 0.103). There was no association with anxiety symptoms and telomere length for either sex.

CONCLUSION

Maternal prenatal depression is associated with sex-specific differences in term placental telomeres. Telomere shortening in female placenta may indicate accelerated placental aging.

In vivo biomarkers of structural and functional brain development and aging in humans

Brain aging is a major determinant of aging. Along with the aging population, prevalence of neurodegenerative diseases is increasing, therewith placing economic and social burden on individuals and society. Individual rates of brain aging are shaped by genetics, epigenetics, and prenatal environmental. Biomarkers of biological brain aging are needed to predict individual trajectories of aging and the risk for age-associated neurological impairments for developing early preventive and interventional measures. We review current advances of in vivo biomarkers predicting individual brain age. Telomere length and epigenetic clock, two important biomarkers that are closely related to the mechanistic aging process, have only poor deterministic and predictive accuracy regarding individual brain aging due to their high intra- and interindividual variability. Phenotype-related biomarkers of global cognitive function and brain structure provide a much closer correlation to age at the individual level. During fetal and perinatal life, autonomic activity is a unique functional marker of brain development. The cognitive and structural biomarkers also boast high diagnostic specificity for determining individual risks for neurodegenerative 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.

Examining developmental plasticity in the skeletal system through a sensitive developmental windows framework

Developmental plasticity facilitates energetically costly but potentially fitness-enhancing adjustments to phenotypic trajectories in response to environmental stressors, and thus may significantly impact patterns of growth, morbidity, and mortality over the life course. Ongoing research into epigenetics and developmental biology indicate that the timing of stress exposures is a key factor when assessing their impact on developmental processes. Specifically, stress experienced within sensitive developmental windows (SDWs), discrete developmental periods characterized by heightened energy requirements and rapid growth, may alter the pace and tempo of growth in ways that significantly influence phenotypic development over both the short and long term. In human skeletal biology, efforts to assess how developmental environments shape health outcomes over the life course could be enhanced by incorporating the SDW concept into existing methodological approaches. The goal of this article is to outline an interpretive framework for identifying and interpreting evidence of developmental stress in the skeletal system using the SDW concept. This framework provides guidance for the identification of elements most likely to capture evidence of stress most relevant to a study's core research questions, the interpretation of developmental stress exhibited by those elements, and the relationship of skeletal indicators of stress to the demographic patterning of morbidity and mortality. Use of the SDW concept in skeletal biology has the potential to enrich traditional approaches to addressing developmental origins of health and disease hypotheses, by targeting periods in which individuals are most susceptible to stress and thus most likely to exhibit plasticity in response.

Telomere Shortening and Psychiatric Disorders: A Systematic Review

Telomeres are aging biomarkers, as they shorten while cells undergo mitosis. The aim of this study was to evaluate whether psychiatric disorders marked by psychological distress lead to alterations to telomere length (TL), corroborating the hypothesis that mental disorders might have a deeper impact on our physiology and aging than it was previously thought. A systematic search of the literature using MeSH descriptors of psychological distress ("Traumatic Stress Disorder" or "Anxiety Disorder" or "depression") and telomere length ("cellular senescence", "oxidative stress" and "telomere") was conducted on PubMed, Cochrane Library and ScienceDirect databases. A total of 56 studies (113,699 patients) measured the TL from individuals diagnosed with anxiety, depression and posttraumatic disorders and compared them with those from healthy subjects. Overall, TL negatively associates with distress-related mental disorders. The possible underlying molecular mechanisms that underly psychiatric diseases to telomere shortening include oxidative stress, inflammation and mitochondrial dysfunction linking. It is still unclear whether psychological distress is either a cause or a consequence of telomere shortening.

Social vulnerabilities for substance use: Stressors, socially toxic environments, and discrimination and racism

Applying a social determinants of health framework, this review brings attention to evidence from social sciences and neuroscience on the role of selected social factors in individual and population-level vulnerability to substance use and substance use disorders (SUDs). The understanding that social vulnerability to substance use and SUDs is multifaceted and occurs across different levels of influence (individual, interpersonal, community, and societal) is underscored. We propose that socially based stressors play a critical role in creating vulnerability to substance use and SUDs, and as such, deserve greater empirical attention to further understand how they "get under the skin." Current knowledge from social sciences and neuroscience on the relationships among vulnerability to substance use resulting from stressors, exposure to socially toxic childhood environments, and racism and discrimination are summarized and discussed, as are implications for future research, practice, and policy. Specifically, we propose using a top-down approach to the examination of known, yet often unexplored, relationships between vulnerability to substance use and SUDs, related inequities, and potential differential effects across demographic groups. Finally, research gaps and promising areas of research, practice, and policy focused on ameliorating social vulnerabilities associated with substance use and SUDs across the lifespan are presented. This article is part of the special issue on 'Vulnerabilities to Substance Abuse'.

Contrasting associations between nestling telomere length and pre and postnatal helpers' presence in a cooperatively breeding bird

Studies on cooperative breeders have addressed the effects of non-breeding 'helpers' on reproduction and parental care, but the consequences for offspring physiology and long-term survival are less understood. Helpers are expected to benefit offspring, but their presence can also lead to decreased pre- or post-natal parental reproductive effort. To examine whether prenatal and postnatal helpers influence offspring condition, we conducted a whole-clutch cross-fostering experiment in sociable weavers (Philetairus socius) that altered the nestlings' social environment (presence/absence of helpers). We tested whether relative telomere length (rTL), an indicator of somatic maintenance, was influenced by prenatal and/or postnatal presence of helpers 9 and 17 days after hatching, and whether rTL predicted long-term survival. Nine days after hatching, we found an overall positive effect of postnatal helpers on rTL: for nestlings with prenatal helpers, a reduction in the number of helpers post-hatch was associated with shorter telomeres, while nestlings swapped from nests without helpers to nests with helpers had a larger rTL. However, when prenatal helpers were present, an increased number of helpers after hatching led to shorter telomeres. Nine-day old chicks with longer rTL tended to be more likely to survive over the 5 years following hatching. However, close to fledging, there was no detectable effect of the experiment on rTL and no link between rTL and survival. This experimental study of a wild cooperative breeder, therefore, presents partial support for the importance of the presence of helpers for offspring rTL and the link between early-life telomere length and long-term survival.

Telomere length determinants in childhood

Telomere length (TL) is a dynamic marker that reflects genetic predispositions together with the environmental conditions of an individual. It is closely related to longevity and a number of pathological conditions. Even though the extent of telomere research in children is limited compared to that of adults, there have been a substantial number of studies providing first insights into child telomere biology and determinants. Recent discoveries revealed evidence that TL is, to a great extent, determined already in childhood and that environmental conditions in adulthood have less impact than first believed. Studies have demonstrated that large inter-individual differences in TL are present among newborns and are determined by diverse factors that influence intrauterine development. The first years of child growth are associated with high cellular turnover, which results in fast shortening of telomeres. The rate of telomere loss becomes stable in early adulthood. In this review article we summarise the existing knowledge on telomere dynamics during the first years of childhood, highlighting the conditions that affect newborn TL. We also warn about the knowledge gaps that should be filled to fully understand the regulation of telomeres, in order to implement them as biomarkers for use in diagnostics or treatment.