Early Life Research Articles

The origins of mammal growth patterns during the Jurassic mammalian radiation.

We use synchrotron x-ray tomography of annual growth increments in the dental cementum of mammaliaforms (stem and crown fossil mammals) from three faunas across the Jurassic to map the origin of patterns of mammalian growth patterns, which are intrinsically related to mammalian endothermy. Although all fossils studied exhibited slower growth rates, longer life spans, and delayed sexual maturity relative to comparably sized extant mammals, the earliest crown mammals developed significantly faster growth rates in early life that reduced at sexual maturity, compared to stem mammaliaforms. Estimation of basal metabolic rates (BMRs) suggests that some fossil crown mammals had BMRs approaching the lowest rates of extant mammals. We suggest that mammalian growth patterns first evolved during their mid-Jurassic adaptive radiation, although growth remained slower than in extant mammals.

Early childhood risk factors for later onset of pediatric chronic pain: a multi-method longitudinal study

BackgroundPediatric chronic pain (i.e., pain lasting ≥ 3 months) is prevalent, disabling, and costly. It spikes in adolescence, interrupts psychosocial development and functioning, and often co-occurs with mental health problems. Chronic pain often begins spontaneously without prior injuries and/or other disorders. Prospective longitudinal cohort studies following children from early childhood, prior to chronic pain onset, are needed to examine contributing factors, such as early pain experiences and mental health. Using data from a longitudinal community pregnancy cohort (All Our Families; AOF), the present study examined the associations between early developmental risk factors, including early childhood pain experiences and mental health symptoms, and the onset of pediatric chronic pain at ages 8 and 11 years.MethodsAvailable longitudinal AOF data from child age 4 months, as well as 1, 2, 3, 5, 8, and 11 years, were used. Mothers reported their child’s pain experiences (e.g., hospitalizations, vaccinations, gut problems) at each timepoint from 4 months to 8 years, child chronic pain at age 8, and child mental health symptoms at ages 5 and 8 years. Children reported their chronic pain frequency and interference at age 11. Adaptive least absolute shrinkage and selection operator (LASSO) regressions were used to select predictor variables. Complete case analyses were complemented by multiple imputation using chained equation (MICE) models.ResultsGut problems, emergency room visits, frequent pain complaints, and headaches at age 5 or earlier, as well as female sex, were associated with increased risk of maternal reported child chronic pain at age 8. Maternal reported chronic pain at age 8 was associated with higher levels of child-reported pain frequency and pain interferences at age 11. Boys self-reported lower levels of pain interference at age 11.ConclusionsSome, but not all, painful experiences (e.g., gut problems, ER visits, pain complaints) in early life contribute to pediatric chronic pain onset and should be considered for screening and early intervention.

Beneficial effects of short-term breastfeeding versus non-breastfeeding in early life against childhood obesity: findings from the US-based population study NHANES

BackgroundBreastfeeding is widely recognized for its potential to reduce childhood obesity. However, research investigating these benefits in children breastfed for a short duration (up to 6 months) remains limited despite this being a common practice globally.MethodsThis study focused on a population breastfed for 6 months or less to determine the potential benefits of short-term breastfeeding for preventing childhood obesity. Data were collected from five survey cycles of an US-based population study (the National Health and Nutrition Examination Survey (NHANES)), spanning 2009–2020. A sample of 3,211 children aged 2–6 years was selected, including 1,373 never breastfed and 1,838 ever breastfed. Logistic regression analysis examined the direct association between short-term breastfeeding and childhood obesity. Subsequent subgroup analyses were conducted. Additionally, stratified logistic regression explored the relationship between childhood obesity and the introduction of other early nutrition in both ever-breastfed and never-breastfed children.ResultsOverall, breastfeeding for 6 months or less did not directly prevent childhood obesity. However, among participants with older mothers (aged 35 or above), short-term breastfeeding was associated with a lower risk of childhood obesity compared to never being breastfed (OR 0.31, 95% CI: 0.17, 0.59). Similarly, children aged 3–4 years who were breastfed for > 3 ~ 6 months exhibited a lower obesity risk (OR 0.56, 95% CI: 0.35, 0.89). In ever-breastfed children, delayed infant formula introduction was linked to a lower risk of obesity (P-trend < 0.05: introduction at age ≤ 1 vs. >1 ~ 3 vs. >3 months). Conversely, for non-breastfed children, introducing milk (other than breast milk or formula) later (≥ 12 versus < 12 months) and introducing alternatives to whole cow’s milk were associated with lower obesity risks (OR 0.54, 95% CI: 0.37, 0.78; OR 0.21, 95% CI: 0.08, 0.60, respectively). Notably, these trends were not observed in ever-breastfed children.ConclusionsShort-term breastfeeding may offer some benefits in preventing childhood obesity for specific populations. Additionally, it could potentially mitigate risks associated with the introduction of formula and cow’s milk at inappropriate times.

Male autism spectrum disorder is linked to brain aromatase disruption by prenatal BPA in multimodal investigations and 10HDA ameliorates the related mouse phenotype

Male sex, early life chemical exposure and the brain aromatase enzyme have been implicated in autism spectrum disorder (ASD). In the Barwon Infant Study birth cohort (n = 1074), higher prenatal maternal bisphenol A (BPA) levels are associated with higher ASD symptoms at age 2 and diagnosis at age 9 only in males with low aromatase genetic pathway activity scores. Higher prenatal BPA levels are predictive of higher cord blood methylation across the CYP19A1 brain promoter I.f region (P = 0.009) and aromatase gene methylation mediates (P = 0.01) the link between higher prenatal BPA and brain-derived neurotrophic factor methylation, with independent cohort replication. BPA suppressed aromatase expression in vitro and in vivo. Male mice exposed to mid-gestation BPA or with aromatase knockout have ASD-like behaviors with structural and functional brain changes. 10-hydroxy-2-decenoic acid (10HDA), an estrogenic fatty acid alleviated these features and reversed detrimental neurodevelopmental gene expression. Here we demonstrate that prenatal BPA exposure is associated with impaired brain aromatase function and ASD-related behaviors and brain abnormalities in males that may be reversible through postnatal 10HDA intervention.

The role of VEGF and TGF-β blood levels for fibroid shrinkage, menorrhagia score, and quality of life improvement after uterine artery embolization for uterine fibroids: a study protocol

Uterine leiomyoma is a common condition affecting women that occurs in more than 70% of females. Women with leiomyomas overall have lower quality of life and deficiency in many specific spheres of life including work-related productivity, sexuality, relationships, social–emotional health, and physical well-being that might be present even in pre-and extended throughout early postmenopausal life. Choices for symptomatic fibroid management include medical, interventional radiology procedures, surgical, and expectant management. The uterine artery embolization (UAE) procedure has gained justified popularity for myoma management. Growth factors, vascular endothelial growth factor (VEGF) and tumor growth factor β (TGF-β), hold an important role in leiomyoma progression. However, blood levels of VEGF and TGF-β in patients before and after UAE are not fully investigated and the possible relationship with myoma shrinkage has not been evaluated. Therefore, this study aims to assess menorrhagia score and quality of life improvement after UAE for uterine fibroids and compare blood levels of VEGF and TGF-β in patients with uterine leiomyoma before and after UAE. This cross-sectional study will be performed at the University Medical Center, Astana, Kazakhstan. Women undergoing the UAE procedure for uterine leiomyoma will be involved in the study following the precisely defined inclusion/exclusion criteria. Uterine leiomyoma nodules’ structural changes after UAE will be assessed along with the blood levels of growth factors (VEGF and TGF-β), menorrhagia score, and quality of life. An important outcome of this project will be an investigation of the blood levels of growth factors (VEGF and TGF-β) before and after the procedure and their association with leiomyoma shrinkage in correlation with the menorrhagia score and quality of life alterations among patients undergoing UAE.

Reduced Gut Bacterial Diversity in Early Life Predicts Feeding Intolerance in Preterm Neonates

Microbiota plays a crucial role in intestinal maturation in preterm newborns. The clinical manifestation of the immaturity of the gastro-intestinal tract is called feeding intolerance (FI). This condition may resolve spontaneously or dramatically evolve into necrotizing enterocolitis. One of the most challenging tasks for the neonatologist is to identify those neonates that will develop the disease early in order to adequately provide nutrition to these patients, from the very first hours of life. A close interplay between the maturity of the gastro-intestinal tract and gut microbiota has been described; however, in preterm neonates, this relationship is still undefined. We analyzed the bacterial composition of stool samples, collected early in life, from 30 preterm newborns classified as intolerant or tolerant according to the degree of readiness of the gastro-intestinal tract to receive enteral nutrition. The Pielou evenness index was significantly increased in intolerant compared with tolerant newborns. Data corrected for confounding variables confirmed that the occurrence of gut maturation was independently influenced by Pielou evenness at birth. A lower bacterial diversity very early in life is associated with improved feeding tolerance in preterm newborns. The abundance analysis showed that neonates not ready to receive enteral nutrition for feeding intolerance show, after birth, an increased abundance of Proteobacteria, Lachnospiracae, Enterobacter and Acinetobacter. We can argue that those are the taxa that prevent the establishment of pioneer bacteria. A lower alpha-diversity, in the first days of life, may facilitate the seeding of beneficial pioneer bacteria that, in turn, drive healthy microbial colonization during neonatal life.

Selection for greater dispersal in early life leads to faster age-dependent decline in locomotor activity and shorter lifespan.

Locomotor activity is one of the major traits that is affected by age. Greater locomotor activity is also known to evolve in the course of dispersal evolution. However, the impact of dispersal evolution on the functional senescence of locomotor activity is largely unknown. We addressed this knowledge gap using large outbred populations of Drosophila melanogaster selected for increased dispersal. We tracked locomotor activity of these flies at regular intervals until a late age. Longevity of these flies was also recorded. We found that locomotor activity declines with age in general. However interestingly, activity level of dispersal selected populations never drops below the ancestry-matched-controls, despite the rate of age-dependent decline in activity of the dispersal selected populations being greater than their respective controls. Dispersal selected population was also found to have shorter lifespan as compared to its control, a potential cost of elevated level of activity throughout their life. These results are crucial in the context of invasion biology as contemporary climate change, habitat degradation, and destruction provide congenial conditions for dispersal evolution. Such controlled and tractable studies investigating the ageing pattern of important functional traits are important in the field of biogerontology as well.

Water-accommodated fractions of heavy and light oils impact DNA integrity, embryonic development, and immune system of Japanese medaka at early life stages.

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants generally found in complex mixtures. PAHs are known to cause pleiotropic effects on living organisms, including developmental defects, mutagenicity, carcinogenicity and immunotoxicity, and endocrine disruptions. The main goal of this study is to evaluate the toxicity of water-accommodated fractions (WAFs) of oils in two life stages of the Japanese medaka, larvae and juveniles. The deleterious effects of an acute exposure of 48h to two WAFs from Arabian light crude oil (LO) and refined oil from Erika (HO) were analyzed in both stages. Relevant endpoints, including ethoxy resorufin-O-deethylase (EROD) activity, DNA damage (Comet assay), photomotor response, and sensitivity to nervous necrosis virus (NNV) infection, were investigated. Larvae exposed to both oil WAFs displayed a significant induction of EROD activity, DNA damage, and developmental anomalies, but no behavioral changes. Deleterious effects were significantly increased following exposure to 1 and 10μg/L of LO WAFs and 10μg/L of HO WAFs. Larval infection to NNV induced fish mortality and sharply reduced reaction to light stimulation. Co-exposure to WAFs and NNV increased the mortality rate, suggesting an impact of WAFs on fish defense capacities. WAF toxicity on juveniles was only observed following the NNV challenge, with a higher sensitivity to HO WAFs than to LO WAFs. This study highlighted that environmentally realistic exposure to oil WAFs containing different compositions and concentrations of oil generated high adverse effects, especially in the larval stage. This kind of multi-marker approach is particularly relevant to characterize the toxicity fingerprint of environmental mixtures of hydrocarbons and PAHs.

Novel high-throughput oxygen saturation measurements for quantifying the physiological performance of macroalgal early life stages.

Understanding how macroalgal forests will respond to environmental change is critical for predicting future impacts on coastal ecosystems. Although measures of adult macroalgae physiological responses to environmental stress are advancing, measures of early life-stage physiology are rare, in part due to the methodological difficulties associated with their small size. Here we tested a novel, high-throughput method (rate of oxygen consumption and production; ) via a sensor dish reader microplate system to rapidly measure physiological rates of the early life stages of three habitat-forming macroalgae, the kelp Ecklonia radiata and the fucoids Hormosira banksii and Phyllospora comosa. We measured the rate of O2 consumption (respiration) and O2 production (net primary production) to then calculate gross primary production (GPP) under temperatures representing their natural thermal range. The microplate system was suitable for rapidly measuring physiological rates over a temperature gradient to establish thermal performance curves for all species. The microplate system proved efficient for measures of early life stages of macroalgae ranging in size from approximately 50 μm up to 150 mm. This method has the potential for measuring responses of early life stages across a range of environmental factors, species, populations, and developmental stages, vastly increasing the speed, precision, and efficacy of macroalgal physiological measures under future ocean change scenarios.

Extending Genetic Algorithms with Biological Life-Cycle Dynamics

In this paper, we aim to enhance genetic algorithms (GAs) by integrating a dynamic model based on biological life cycles. This study addresses the challenge of maintaining diversity and adaptability in GAs by incorporating stages of birth, growth, reproduction, and death into the algorithm’s framework. We consider an asynchronous execution of life cycle stages to individuals in the population, ensuring a steady-state evolution that preserves high-quality solutions while maintaining diversity. Experimental results demonstrate that the proposed extension outperforms traditional GAs and is as good or better than other well-known and well established algorithms like PSO and EvoSpace in various benchmark problems, particularly regarding convergence speed and solution qu/ality. The study concludes that incorporating biological life-cycle dynamics into GAs enhances their robustness and efficiency, offering a promising direction for future research in evolutionary computation.

The complicated relationship between asthma and swimming

Introduction: Apart from pharmacological treatment, non-pharmacological strategies including physical activity play a significant role in the management of asthma. The aim of this paper is to examine various topics related to swimming and asthma. They include the detailed effect of swimming on asthma control,the potential role of swimming in early childhood asthma development, exercise induced asthma in swimmers as well as the relationship between asthma and cold water swimming. Review methods: This article is based on the literature found in the PubMed Database from the period of 1971-2024 with the use of keywords such as “asthma”, “swimming”, “cold water swimming”, “exercise induced asthma”, “childhood asthma” Description of the state of knowledge: Swimming is a safe form of physical activity for asthma patients.Swimming training enhances aerobic capacity, reduces exercise-induced bronchoconstriction and improves lung function in both pediatric and adult patients. However, there is a concern regarding indoor swimming pools that chlorine can potentially induce airway inflammation. There is research suggesting that early life swimming pool exposure may contribute to the asthma development in atopic children. There is some premise to the thought that cold water swimming may help alleviate asthma symptoms, but it also carries many risks.Swimming is a major cause of exercise induced asthma in professional athletes. Conclusions: Alongside appropriate pharmacological treatment, swimming is a valuable strategy in asthma management in both pediatric and adult asthma patients. The risks of chlorinating pools are still not known to outweigh the benefits of swimming for asthmatics. Further research should be carried out on safety of early swimming in atopic children. Cold water swimming should also be evaluated in terms of safety and potential benefits for asthma patients.

Grace, too: the sense of agency and Jeremy Safran's relational vision.

The sense of agency, our felt sense of authorship for our actions, is a difficult concept to define, yet its faltering stands at the heart of psychopathology. Historically undertheorized by psychoanalysis and typically positioned opposite relatedness by clinical psychology, Jeremy Safran conceived of agency and relatedness as paradoxically related. This paper pays tribute to Safran's ideas by taking his writings on agency as a starting point to elaborate how agency forms, and goes awry, in the relational crucible of early life. In doing so, the paper draws on the developmental theory of Winnicott, empirical research on embodied agency from adjacent fields of study, and Safran's clinical phenomenology.

Measuring neuroplasticity in human development: the potential to inform the type and timing of mental health interventions.

Neuroplasticity during sensitive periods, the molecular and cellular process of enduring neural change in response to external stimuli during windows of high environmental sensitivity, is crucial for adaptation to expected environments and has implications for psychiatry. Animal research has characterized the developmental sequence and neurobiological mechanisms that govern neuroplasticity, yet gaps in our ability to measure neuroplasticity in humans limit the clinical translation of these principles. Here, we present a roadmap for the development and validation of neuroimaging and electrophysiology measures that index neuroplasticity to begin to address these gaps. We argue that validation of measures to track neuroplasticity in humans will elucidate the etiology of mental illness and inform the type and timing of mental health interventions to optimize effectiveness. We outline criteria for evaluating putative neuroimaging measures of plasticity in humans including links to neurobiological mechanisms shown to govern plasticity in animal models, developmental change that reflects heightened early life plasticity, and prediction of neural and/or behavior change. These criteria are applied to three putative measures of neuroplasticity using electroencephalography (gamma oscillations, aperiodic exponent of power/frequency) or functional magnetic resonance imaging (amplitude of low frequency fluctuations). We discuss the use of these markers in psychiatry, envision future uses for clinical and developmental translation, and suggest steps to address the limitations of the current putative neuroimaging measures of plasticity. With additional work, we expect these markers will significantly impact mental health and be used to characterize mechanisms, devise new interventions, and optimize developmental trajectories to reduce psychopathology risk.

Lifestyle, cognitive, and psychological factors associated with a resilience phenotype in aging: a multidimensional approach on a population-based sample of oldest-old (80+).

To investigate the determinants of resilience phenotype in aging, operationalized as the maintenance of cognitive, physical, and psychological health in very old individuals (80+), we investigated the structure and interrelated impact of the main resilience-enhancing factors, which are usually studied in separate research fields. Participants were older adults without dementia recruited for the fifth wave of the InveCe.Ab population-based cohort study (aged 83-87 years). Multidimensional evaluation comprised blood sampling, social and lifestyle survey, geriatric and neuropsychological assessment. We classified resilient individuals as displaying normal cognition, functional independence, and mental health. First, we performed exploratory factor analysis (EFA) to examine the underlying structure of the relevant cognitive, lifestyle, physical, and psychological resilience-enhancing factors. The factors obtained were included as predictors of the resilience phenotype in the logistic regression model, controlling for sociodemographic and cumulative exposure to physical and psychosocial stressors, including COVID-19 infection. Among the 404 enrolled participants, 153 (38%) exhibited the resilience phenotype. EFA resulted in the identification of 6 factors (59% of variance): cognitive reserve, affective reserve, insecure attachment, current lifestyle, physical reserve, and avoidant attachment. Among these factors, cognitive reserve, affective reserve, and current lifestyle significantly and independently predicted resilience status, controlling for cumulative exposure to age-related stressors and COVID-19 infection. Our findings showed that, even in very old age, both early and late life modifiable factors affect individuals' ability to adapt to the aging process, thus confirming the importance of a life-course approach to improve health outcomes in the aged population.

Disentangling the roles of age and knowledge in early language acquisition: A fine-grained analysis of the vocabularies of infant and child language learners

The words that children learn change over time in predictable ways. The first words that infants acquire are generally ones that are both frequent and highly imageable. Older infants also learn words that are more abstract and some that are less common. It is unclear whether this pattern is attributable to maturational factors (i.e., younger children lack sufficiently developed cognitive faculties needed to learn abstract words) or linguistic factors (i.e., younger children lack sufficient knowledge of their language to use grammatical or contextual cues needed to figure out the meaning of more abstract words). The present study explores this question by comparing vocabulary acquisition in 53 preschool-aged children (M = 51 months, range = 30–76 months) who were adopted from China and Eastern Europe after two and half years of age and 53 vocabulary-matched infant controls born and raised in English speaking families in North America (M = 24 months, range = 16–33 months). Vocabulary was assessed using the MB-CDI Words and Sentences form, word frequency was estimated from the CHILDES database, and imageability was measured using adult ratings of how easily words could be pictured mentally. Both groups were more likely to know words that were both highly frequent and imageable (resulting in an over-additive interaction). Knowledge of a word was also independently affected by the syntactic category that it belongs to. Adopted preschoolers’ vocabulary was slightly less affected by imageability. These findings were replicated in a comparison with a larger sample of vocabulary-matched controls drawn from the MB-CDI norming study (M = 22 months, range = 16–30 months; 33 girls). These results suggest that the patterns of acquisition in children’s early vocabulary are primarily driven by the accrual of linguistic knowledge, but that vocabulary may also be affected by differences in early life experiences or conceptual knowledge.

How maternal caring affects longevity

When it comes to longevity, everyone wants to live for eternity. Longevity research has often led scientists to dark alleys with several candidate molecules responsible for aging. Pioneering genetic studies on model organisms like Caenorhabditis elegans and Drosophila melanogaster discovered the most well-conserved longevity pathways, mainly caloric restriction and the insulin/insulin-like growth factor 1signaling pathways. Apart from these complex molecular circuitries that drive longevity, a recent study published by Zipple et al. (Proceedings of the National Academy of Sciences, 2024) showed that the relationship between mother and grandmother with the child may determine why some animals and humans live longer than expected for their size. Animals that spend more time with their mothers during early life end up living longer but with reduced capacity to produce offspring. This exciting piece of research has far more consequences than just these findings. It implies the importance of the mother in one’s life and the role of parental care in providing longevity and reproductive success.

Effect of enhanced plane of nutrition in early life on the transcriptome and proteome of the anterior pituitary gland in Angus heifer calves

BackgroundEnhanced nutrition during the early calfhood period has been shown to lead to earlier pubertal development in heifer calves. This is of interest as earlier pubertal onset can subsequently facilitate earlier calving which can economically benefit production systems. Reproductive development in heifers is regulated by the hypothalamic-pituitary-ovarian signalling pathway. In particular the anterior pituitary gland is central to reproductive development, through the dynamics of gonadotropic pulsatility. However, despite clear knowledge of the influence of enhanced dietary intake on subsequent reproductive development, the molecular control governing this response in the pituitary gland within the hypothalamic-pituitary-ovarian signalling axis in heifer calves is not fully understood. The objective of this study was to examine the effect of an enhanced plane of nutrition during early life on the anterior pituitary gland of heifer calves through both transcriptomic and proteomic analyses. Between 3 and 21 weeks of age, heifer calves were offered either a high (HI, n = 14) or moderate (MOD, n = 14) plane of nutrition, designed to elicit target growth rates of 1.2 and 0.5 kg/d for HI and MOD groups, respectively. All calves were euthanised at 21 weeks of age and anterior pituitary tissue harvested for subsequent use in global transcriptomic and proteomic analyses.ResultsAverage daily gain was affected by diet (P < 0.001) and was 1.18 and 0.50 kg/day, for HI and MOD calves, respectively. RNAseq analysis resulted in the identification of 195 differentially expressed genes (Padj<0.05; fold change > 1.5), with 277 proteins identified as differentially abundant (Padj<0.05; fold change > 1.5) between contrasting dietary treatment groups. Biochemical pathway analysis of differentially affected genes and proteins revealed an enrichment for both growth hormone and GnRH signalling pathways (Padj.<0.05). Additionally, pathway analysis predicted an effect of enhanced dietary intake on endocrine function within the anterior pituitary gland as well as on reproductive system development and function (Padj.<0.05).ConclusionsResults from this study show that an enhanced dietary intake during early calfhood affected the molecular control of the anterior pituitary gland in heifer calves in early life.

Prenatal and early-life air pollutant exposure and epigenetic aging acceleration

BackgroundThis study investigated the association of prenatal and early childhood exposure to air pollution with epigenetic age acceleration (EAA) at six years of age using the Environment and Development of Children Cohort (EDC Cohort) Materials & methodsAir pollution, including particulate matter [< 2.5 µm (PM2.5) and < 10 µm (PM10) in an aerodynamic diameter], nitrogen dioxide (NO2), ozone (O3), carbon monoxide (CO), and sulfur dioxide (SO2) were estimated based on the residential address for two periods: 1) during the whole pregnancy, and 2) for one year before the follow-up in children at six years of age. The methylation levels in whole blood at six years of age were measured, and the methylation clocks, including Horvath’s clock, Horvath’s skin and blood clock, PedBE, and Wu’s clock, were estimated. Multivariate linear regression models were constructed to analyze the association between EAA and air pollutants. ResultsA total of 76 children in EDC cohort were enrolled in this study. During the whole pregnancy, interquartile range (IQR) increases in exposure to PM2.5 (4.56 μg/m3) and CO (0.156 ppm) were associated with 0.406 years and 0.799 years of EAA (Horvath’s clock), respectively. An IQR increase in PM2.5 (4.76 μg/m3) for one year before the child was six years of age was associated with 0.509 years of EAA (Horvath’s clock) and 0.289 years of EAA (Wu’s clock). PM10 (4.30 μg/m3) and O3 (0.003 ppm) exposure in the period were also associated with EAA in Horvath’s clock (0.280 years) and EAA in Horvath’s skin and blood clock (0.163 years), respectively. ConclusionWe found that prenatal and childhood exposure to ambient air pollutants is associated with EAA among children. The results suggest that air pollution could induce excess biological aging even in prenatal and early life.

A Quantitative Adverse Outcome Pathway for Embryonic Activation of the Aryl Hydrocarbon Receptor of Fishes by Polycyclic Aromatic Hydrocarbons Leading to Decreased Fecundity at Adulthood.

Quantitative adverse outcome pathways (qAOPs) describe the response-response relationships that link the magnitude and/or duration of chemical interaction with a specific molecular target to the probability and/or severity of the resulting apical-level toxicity of regulatory relevance. The present study developed the first qAOP for latent toxicities showing that early life exposure adversely affects health at adulthood. Specifically, a qAOP for embryonic activation of the aryl hydrocarbon receptor 2 (AHR2) of fishes by polycyclic aromatic hydrocarbons (PAHs) leading to decreased fecundity of females at adulthood was developed by building on existing qAOPs for (1) activation of the AHR leading to early life mortality in birds and fishes, and (2) inhibition of cytochrome P450 aromatase activity leading to decreased fecundity in fishes. Using zebrafish (Danio rerio) as a model species and benzo[a]pyrene as a model PAH, three linked quantitative relationships were developed: (1) plasma estrogen in adult females as a function of embryonic exposure, (2) plasma vitellogenin in adult females as a function of plasma estrogen, and (3) fecundity of adult females as a function of plasma vitellogenin. A fourth quantitative relationship was developed for early life mortality as a function of sensitivity to activation of the AHR2 in a standardized in vitro AHR transactivation assay to integrate toxic equivalence calculations that would allow prediction of effects of exposure to untested PAHs. The accuracy of the predictions from the resulting qAOP were evaluated using experimental data from zebrafish exposed as embryos to another PAH, benzo[k]fluoranthene. The qAOP developed in the present study demonstrates the potential of the AOP framework in enabling consideration of latent toxicities in quantitative ecological risk assessments and regulatory decision-making. Environ Toxicol Chem 2024;00:1-12. © 2024 SETAC.

Multiple climate change stressors reduce the emergence success of gravel-spawning fish species and alter temporal emergence patterns

Climate change, with its profound effects on stream sediment, hydrological, and temperature dynamics, will exacerbate impacts on habitat conditions for many species, particularly those with vulnerable early life stages relying on the hyporheic zone, such as gravel-spawning fishes. Due to the complex and interactive nature of multiple stressor effects, we employed large-scale outdoor mesocosms to systemically test how the reproductive success of three gravel-spawning fish species brown trout (Salmo trutta), nase, (Chrondrostoma nasus) and Danube salmon (Hucho hucho) was affected by individual and combined effects of warming (+3–4 °C), fine sediment (increase in <0.85 mm by 22 %) and low-flow (eightfold discharge-reduction). Fine sediment had the most detrimental effect on emergence rate and fry length in all three species, reducing the emergence rate to zero in brown trout, 9 % in nase, and 4 % in Danube salmon. The emergence mortality caused by fine sediment surpassed that of hatching distinctly, suggesting that negative effects due to hypoxia were considerably exacerbated by entombment. Warming had only minor effects as a single stressor, but low flow reduced emergence rates of the spring spawning species nase and Danube salmon by 8 and 50 %, respectively. In combined treatments including fine sediment, however, the emergence success of all three species responded strongly negatively, even in the cyprinid species nase, which showed little interactive effects between stressors regarding hatching success. Warming and fine sediment also led to the earlier emergence of fry, implying a risk of asynchrony with available food resources. This study dramatically shows that climate change can have deleterious impacts on the reproductive success of gravel-spawning fish species, irrespective of taxonomic or ecological traits.