A future food boom rescues the negative effects of early-life adversity on adult lifespan in a small mammal

Early-life adversity, even when transient, can have lasting effects on individual phenotypes and reduce lifespan across species. If these effects can be mitigated by a high-quality later-life environment, then differences in future resources may explain variable resilience to early-life adversity. Using data from over 1000 wild North American red squirrels, we tested the hypothesis that the costs of early-life adversity for adult lifespan could be offset by later-life food abundance. We identified six adversities that reduced juvenile survival in the first year of life, though only one-birth date-had continued independent effects on adult lifespan. We then built a weighted early-life adversity (wELA) index integrating the sum of adversities and their effect sizes. Greater weighted early-life adversity predicted shorter adult lifespans in males and females, but a naturally occurring food boom in the second year of life ameliorated this effect. Experimental food supplementation did not replicate this pattern, despite increasing lifespan, indicating that the buffering effect of a future food boom may hinge on more than an increase in available calories. Our results suggest a non-deterministic role of early-life conditions for later-life phenotype, highlighting the importance of evaluating the consequences of early-life adversity in the context of an animal's entire life course.

The role of epigenetic mechanisms in the long-term effects of early-life adversity and mother-infant relationship on physiology and behavior of offspring in laboratory rats and mice

Maternal care during the early postnatal period of altricial mammals is a key factor in the survival and adaptation of offspring to environmental conditions. Natural variations in maternal care and experimental manipulations with maternal-child relationships modeling early-life adversity (ELA) in laboratory rats and mice have a strong long-term influence on the physiology and behavior of offspring in rats and mice. This literature review is devoted to the latest research on the role of epigenetic mechanisms in these effects of ELA and mother-infant relationship, with a focus on the regulation of hypothalamic-pituitary-adrenal axis and brain-derived neurotrophic factor. An important part of this review is dedicated to pharmacological interventions and epigenetic editing as tools for studying the causal role of epigenetic mechanisms in the development of physiological and behavioral profiles. A special section of the manuscript will discuss the translational potential of the discussed research.

Impact of Early-Life Adversity on Cannabis Use: Exploring the Mediating and Moderating Effects of Chronic Pain

Background: Although research suggests that early-life adversity (ELA) and cannabis use are linked, researchers have not established factors that mediate or modify this relationship. Identifying such factors could help in developing targeted interventions. We explored chronic pain as a potential mediator or moderator of this relationship. Methods: Using an online study, we collected cross-sectional data about ELA, cannabis use, and chronic pain to test whether ELA (adverse childhood experiences total score) is associated with cannabis use, and to examine pain as a potential mediator or moderator. Cannabis use was examined two ways: times used per day, and categorized as non-, some, or regular use. Chronic pain was measured as present/absent and as the number of painful body locations (0-8). Analyses used linear and multinomial regression. Results: ELA, chronic pain, and cannabis use were common among respondents. ELA was strongly associated with both measures of cannabis use. The number of painful body locations modestly mediated the association of ELA with cannabis use, reducing the magnitude of regression coefficients by about 1/7. The number of painful body locations modified the association between ELA and cannabis use (p≤0.006), while chronic pain presence/absence (a less-informative measure) had only a nonsignificant modification effect (p≥0.10). When either ELA or pain was high, the other was not associated with cannabis use; when either ELA or pain was low, more painful locations or higher ELA (respectively) was associated with more intense cannabis use. Conclusion: These exploratory findings suggest the importance of ELA and chronic pain as factors contributing to cannabis use, and of accounting for these factors in developing treatment and prevention strategies addressing cannabis use.

Within-subject changes in methylome profile identify individual signatures of early-life adversity, with a potential to predict neuropsychiatric outcome

Background

Adverse early-life experiences (ELA), including poverty, trauma and neglect, affect a majority of the world's children. Whereas the impact of ELA on cognitive and emotional health throughout the lifespan is well-established, it is not clear how distinct types of ELA influence child development, and there are no tools to predict for an individual child their vulnerability or resilience to the consequences of ELAs. Epigenetic markers including DNA-methylation profiles of peripheral cells may encode ELA and provide a predictive outcome marker. However, the rapid dynamic changes in DNA methylation in childhood and the inter-individual variance of the human genome pose barriers to identifying profiles predicting outcomes of ELA exposure. Here, we examined the relation of several dimensions of ELA to changes of DNA methylation, using a longitudinal within-subject design and a high threshold for methylation changes in the hope of mitigating the above challenges.

Methods

We analyzed DNA methylation in buccal swab samples collected twice for each of 110 infants: neonatally and at 12 months. We identified CpGs differentially methylated across time, calculated methylation changes for each child, and determined whether several indicators of ELA associated with changes of DNA methylation for individual infants. We then correlated select dimensions of ELA with methylation changes as well as with measures of executive function at age 5 years. We examined for sex differences, and derived a sex-dependent 'impact score' based on sites that most contributed to the methylation changes.

Findings

Setting a high threshold for methylation changes, we discovered that changes in methylation between two samples of an individual child reflected age-related trends towards augmented methylation, and also correlated with executive function years later. Among the tested factors and ELA dimensions, including income to needs ratios, maternal sensitivity, body mass index and sex, unpredictability of parental and household signals was the strongest predictor of executive function. In girls, an interaction was observed between a measure of high early-life unpredictability and methylation changes, in presaging executive function.

Interpretation

These findings establish longitudinal, within-subject changes in methylation profiles as a signature of some types of ELA in an individual child. Notably, such changes are detectable beyond the age-associated DNA methylation dynamics. Future studies are required to determine if the methylation profile changes identified here provide a predictive marker of vulnerabilities to poorer cognitive and emotional outcomes.

Ectoparasite presence and brood size manipulation interact to accelerate telomere shortening in nestling jackdaws

Early-life conditions impact fitness, but whether the combined effect of extrinsic stressors is additive or synergistic is not well known. This is a major knowledge gap because exposure to multiple stressors is frequent. Telomere dynamics may be instrumental when testing how stressors interact because many factors affect telomere shortening, and telomere shortening predicts survival. We evaluated the effect of manipulated brood size and natural infestation by the carnid fly Carnus hemapterus on nestling growth and telomere shortening of wild jackdaws (Corvus monedula). Telomere length, measured in blood using TRF, shortened on average by 264 bp, and on average, Carnus infection induced more telomere shortening. Further analyses showed that in enlarged broods, nestlings' telomeres shortened more when parasitized, while in reduced broods there was no effect of infection on telomere shortening. We conclude that there is a synergistic effect of number of siblings and Carnus infection on telomere shortening rate: blood-sucking parasites may negatively impact telomeres by increasing cell proliferation and/or physiological stress, and coping with infection may be less successful in enlarged broods with increased sibling competition. Larger nestlings had shorter telomeres independent of age, brood manipulation or infection. Growth was independent of infestation but in enlarged broods, nestlings were lighter at fledging. Our findings indicate that (i) evaluating consequences of early-life environmental conditions in isolation may not yield a full picture due to synergistic effects, and (ii) effects of environmental conditions may be cryptic, for example, on telomeres, with fitness consequences expressed beyond the temporal framework of the study.

Biological stability of DNA methylation measurements over varying intervals of time and in the presence of acute stress

Identifying factors that influence the stability of DNA methylation measurements across biological replicates is of critical importance in basic and clinical research. Using a within-person between-group experimental design (n = 31, number of observations = 192), we report the stability of biological replicates over a variety of unique temporal scenarios, both in the absence and presence of acute psychosocial stress, and between individuals who have experienced early life adversity (ELA) and non-exposed individuals. We found that varying time intervals, acute stress, and ELA exposure influenced the stability of repeated DNA methylation measurements. In the absence of acute stress, probes were less stable as time passed; however, stress exerted a stabilizing influence on probes over longer time intervals. Compared to non-exposed individuals, ELA-exposed individuals had significantly lower probe stability immediately following acute stress. Additionally, we found that across all scenarios, probes used in most epigenetic-based algorithms for estimating epigenetic age or immune cell proportions had average or below-average stability, except for the Principal Component and DunedinPACE epigenetic ageing clocks, which were enriched for more stable probes. Finally, using highly stable probes in the absence of stress, we identified multiple probes that were hypomethylated in the presence of acute stress, regardless of ELA status. Two hypomethylated probes are located near the transcription start site of the glutathione-disulfide reductase gene (GSR), which has previously been shown to be an integral part of the stress response to environmental toxins. We discuss implications for future studies concerning the reliability and reproducibility of DNA methylation measurements.Abbreviations: DNAm - DNA methylation, CpG - 5'-cytosine-phosphate-guanine-3,' ICC - Interclass correlation coefficient, ELA - Early-life adversity, PBMCs - Peripheral blood mononuclear cells, mQTL - Methylation quantitative trait loci, TSS - Transcription start site, GSR - Glutathione-disulfide reductase gene, TSST - Trier social stress test, PC - Principal component.

Associations of Early-Life Adversity With Later-Life Epigenetic Aging Profiles in the Multi-Ethnic Study of Atherosclerosis

Epigenetic biomarkers of accelerated aging have been widely used to predict disease risk and may enhance our understanding of biological mechanisms between early-life adversity and disparities in aging. With respect to childhood adversity, most studies have used parental education or childhood disadvantage and/or have not examined the role played by socioemotional or physical abuse and trauma in epigenetic profiles at older ages. This study leveraged data from the Multi-Ethnic Study of Atherosclerosis (MESA) on experiences of threat and deprivation in participants' early lives (i.e., before the age of 18 years) to examine whether exposure to specific dimensions of early-life adversity is associated with epigenetic profiles at older ages that are indicative of accelerated biological aging. The sample included 842 MESA respondents with DNA methylation data collected between 2010 and 2012 who answered questions on early-life adversities in a 2018-2019 telephone follow-up. We found that experiences of deprivation, but not threat, were associated with later-life GrimAge epigenetic aging signatures that were developed to predict mortality risk. Results indicated that smoking behavior partially mediates this association, which suggests that lifestyle behaviors may act as downstream mechanisms between parental deprivation in early life and accelerated epigenetic aging in later life.

Accelerated biological aging six decades after prenatal famine exposure

To test the hypothesis that early-life adversity accelerates the pace of biological aging, we analyzed data from the Dutch Hunger Winter Families Study (DHWFS, N=951). DHWFS is a natural-experiment birth-cohort study of survivors of in-utero exposure to famine conditions caused by the German occupation of the Western Netherlands in Winter 1944-5, matched controls, and their siblings. We conducted DNA methylation analysis of blood samples collected when the survivors were aged 58 to quantify biological aging using the DunedinPACE, GrimAge, and PhenoAge epigenetic clocks. Famine survivors had faster DunedinPACE, as compared with controls. This effect was strongest among women. Results were similar for GrimAge, although effect-sizes were smaller. We observed no differences in PhenoAge between survivors and controls. Famine effects were not accounted for by blood-cell composition and were similar for individuals exposed early and later in gestation. Findings suggest in-utero undernutrition may accelerate biological aging in later life.

Early life drought predicts components of adult body size in wild female baboons

OBJECTIVES

In many taxa, adverse early-life environments are associated with reduced growth and smaller body size in adulthood. However, in wild primates, we know very little about whether, where, and to what degree trajectories are influenced by early adversity, or which types of early adversity matter most. Here, we use parallel-laser photogrammetry to assess inter-individual predictors of three measures of body size (leg length, forearm length, and shoulder-rump length) in a population of wild female baboons studied since birth.

MATERIALS AND METHODS

Using >2000 photogrammetric measurements of 127 females, we present a cross-sectional growth curve of wild female baboons (Papio cynocephalus) from juvenescence through adulthood. We then test whether females exposed to several important sources of early-life adversity-drought, maternal loss, low maternal rank, or a cumulative measure of adversity-were smaller for their age than females who experienced less adversity. Using the "animal model," we also test whether body size is heritable in this study population.

RESULTS

Prolonged early-life drought predicted shorter limbs but not shorter torsos (i.e., shoulder-rump lengths). Our other measures of early-life adversity did not predict variation in body size. Heritability estimates for body size measures were 36%-67%. Maternal effects accounted for 13%-17% of the variance in leg and forearm length, but no variance in torso length.

DISCUSSION

Our results suggest that baboon limbs, but not torsos, grow plastically in response to maternal effects and energetic early-life stress. Our results also reveal considerable heritability for all three body size measures in this study population.

Patterns of resilient functioning in early life: Identifying distinct groups and associated factors

Resilience, the capacity to maintain or regain functionality in the face of adversity, is a dynamic process influenced by individual, familial, and community factors. Despite its variability, distinct resilience trajectories can be identified within populations, yet the predictors defining these distinct groups remains largely unclear. Here, using data from the Avon Longitudinal Study of Parents and Children (ages 0-18), we quantify resilience as the remaining variance in psychosocial functioning after taking into account the exposure to adversity. Growth mixture modeling identified seven distinct resilience trajectories, with over half of the study population maintaining resilience throughout early life. Factors increasing the likelihood of resilient trajectory membership included a less emotional temperament, high cognitive abilities, high self-esteem, low levels of autistic social traits, strong sibling relationships, high maternal care, and positive school experiences. Among the socioeconomic factors considered, maternal education - a significant indicator of socioeconomic status - and birth-order were associated with resilient trajectories. Our findings underscore the importance of fostering cognitive abilities, self-esteem, social relationships, positive school experiences, and extracurricular engagement to bolster resilience in adversity-exposed individuals and communities. This research informs resilience-focused interventions in mental health, education, and social policy sectors, and prompts further exploration of socioeconomic influences on resilience trajectories.

Early-life adversity is associated with poor iron status in infancy

Exposure to early-life adversity (ELA) and iron deficiency early in life are known risk factors for suboptimal brain and socioemotional development. Iron deficiency may arise from and co-occur with ELA, which could negatively affect development. In the present study, we investigated whether ELA is associated with iron deficiency in infants receiving no iron supplementation. This study is a secondary analysis of extant data collected in the 1990s; participants were healthy infants from working-class communities in Santiago, Chile (N = 534, 45.5% female). We measured stressful life events, maternal depression, and low home support for child development during infancy and assessed iron status when the infant was 12 months old. Slightly more than half of the infants were iron-deficient (51%), and 25.8% were iron-deficient anemic at 12 months. Results indicated that ELA was associated with lower iron levels and iron deficiency at 12 months. The findings are consistent with animal and human prenatal models of stress and iron status and provide evidence of the association between postnatal ELA and iron status in humans. The findings also highlight a nutritional pathway by which ELA may impact development and present a nutritionally-focused avenue for future research on ELA and psychopathology.

Review of Major Social Determinants of Health in Schizophrenia-Spectrum Disorders: II. Assessments

BACKGROUND AND AIMS

Social determinants of health (SDoHs) impact the development and course of schizophrenia-spectrum psychotic disorders (SSPDs). Yet, we found no published scholarly reviews of psychometric properties and pragmatic utility of SDoH assessments among people with SSPDs. We aim to review those aspects of SDoH assessments.

STUDY DESIGN

PsychInfo, PubMed, and Google Scholar databases were examined to obtain data on reliability, validity, administration process, strengths, and limitations of the measures for SDoHs identified in a paired scoping review.

STUDY RESULTS

SDoHs were assessed using different approaches including self-reports, interviews, rating scales, and review of public databases. Of the major SDoHs, early-life adversities, social disconnection, racism, social fragmentation, and food insecurity had measures with satisfactory psychometric properties. Internal consistency reliabilities-evaluated in the general population for 13 measures of early-life adversities, social disconnection, racism, social fragmentation, and food insecurity-ranged from poor to excellent (0.68-0.96). The number of items varied from 1 to more than 100 and administration time ranged from less than 5 minutes to over an hour. Measures of urbanicity, low socioeconomic status, immigration status, homelessness/housing instability, and incarceration were based on public records or targeted sampling.

CONCLUSIONS

Although the reported assessments of SDoHs show promise, there is a need to develop and test brief but validated screening measures suitable for clinical application. Novel assessment tools, including objective assessments at individual and community levels utilizing new technology, and sophisticated psychometric evaluations for reliability, validity, and sensitivity to change with effective interventions are recommended, and suggestions for training curricula are offered.

Stressed microglia: Neuroendocrine-neuroimmune interactions in the stress response

Stressful life experiences are associated with the development of neuropsychiatric disorders like depression. Emerging evidence indicates that microglia, the specialized resident macrophages of the brain, may be a key mediator of the relationship between psychosocial stressor exposure and adaptive or maladaptive responses, at the level of synaptic, circuit, and neuroimmune alterations. Here, we review current literature regarding how psychosocial stressor exposure changes microglial structure and function, thereby altering behavioral and brain outcomes, with a particular focus on age- and sex-dependent effects. We argue that additional emphasis should be placed in future research on investigating sex differences and the impacts of stressor exposure during sensitive periods of development, as well as going beyond traditional morphological measurements to interrogate microglial function. The bidirectional relationship between microglia and the stress response, particularly the role of microglia in the neuroendocrine control of stress-related circuits, is also an important area for future investigation. Finally, we discuss emerging themes and future directions that point to the possibility of the development of novel therapeutics for stress-related neuropsychiatric disorders.

Contribution of early-life unpredictability to neuropsychiatric symptom patterns in adulthood

BACKGROUND

Recent studies in both human and experimental animals have identified fragmented and unpredictable parental and environmental signals as a novel source of early-life adversity. Early-life unpredictability may be a fundamental developmental factor that impacts brain development, including reward and emotional memory circuits, affecting the risk for psychopathology later in life. Here, we tested the hypothesis that self-reported early-life unpredictability is associated with psychiatric symptoms in adult clinical populations.

METHODS

Using the newly validated Questionnaire of Unpredictability in Childhood, we assessed early-life unpredictability in 156 trauma-exposed adults, of which 65% sought treatment for mood, anxiety, and/or posttraumatic stress disorder (PTSD) symptoms. All participants completed symptom measures of PTSD, depression and anhedonia, anxiety, alcohol use, and chronic pain. Relative contributions of early-life unpredictability versus childhood trauma and associations with longitudinal outcomes over a 6-month period were determined.

RESULTS

Early-life unpredictability, independent of childhood trauma, was significantly associated with higher depression, anxiety symptoms, and anhedonia, and was related to higher overall symptom ratings across time. Early-life unpredictability was also associated with suicidal ideation, but not alcohol use or pain symptoms.

CONCLUSIONS

Early-life unpredictability is an independent and consistent predictor of specific adult psychiatric symptoms, providing impetus for studying mechanisms of its effects on the developing brain that promote risk for psychopathology.

Canada's Colonial Genocide of Indigenous Peoples: A Review of the Psychosocial and Neurobiological Processes Linking Trauma and Intergenerational Outcomes

The policies and actions that were enacted to colonize Indigenous Peoples in Canada have been described as constituting cultural genocide. When one considers the long-term consequences from the perspective of the social and environmental determinants of health framework, the impacts of such policies on the physical and mental health of Indigenous Peoples go well beyond cultural loss. This paper addresses the impacts of key historical and current Canadian federal policies in relation to the health and well-being of Indigenous Peoples. Far from constituting a mere lesson in history, the connections between colonialist policies and actions on present-day outcomes are evaluated in terms of transgenerational and intergenerational transmission processes, including psychosocial, developmental, environmental, and neurobiological mechanisms and trauma responses. In addition, while colonialist policies have created adverse living conditions for Indigenous Peoples, resilience and the perseverance of many aspects of culture may be maintained through intergenerational processes.

Burden or Blessing? CEO Early-Life Adversity Experience and Firm Internationalization Performance

Firm internationalization is a great challenge that needs a strong leader because of the uncertainty involved. Previous research has examined the antecedents of firm internationalization from the perspective of upper echelons theory, including chief executive officer (CEO) or top management team (TMT) characteristics, yet little research has examined the role of CEO early-life adversity experiences. Based on the imprinting theory and upper echelons theory, this study explores the relationship between CEO early-life adversity experience and firm internationalization. Using data from Chinese listed companies during the period 2007-2017, we demonstrate that CEO early-life adversity experiences have a significantly positive effect on firm internationalization; the effect is stronger when the CEO with early-life adversity has a higher level of organization discretion and institutional discretion. The findings are robust to a battery of alternative variable definitions and estimation methods. We contribute to upper echelons theory and the research on internationalization antecedents by showing that CEO early-life adversity has a positive effect on firm internationalization. The findings suggest boards aspiring to expand internationally place weight on candidates' early-life experiences while selecting and hiring CEOs and confer them managerial discretion to better play their strength after CEO's appointment decision is made.

Neurodevelopmental origins of substance use disorders: Evidence from animal models of early-life adversity and addiction

Addiction is a chronic relapsing disorder with devastating personal, societal, and economic consequences. In humans, early-life adversity (ELA) such as trauma, neglect, and resource scarcity are linked with increased risk of later-life addiction, but the brain mechanisms underlying this link are still poorly understood. Here, we focus on data from rodent models of ELA and addiction, in which causal effects of ELA on later-life responses to drugs and the neurodevelopmental mechanisms by which ELA increases vulnerability to addiction can be determined. We first summarize evidence for a link between ELA and addiction in humans, then describe how ELA is commonly modeled in rodents. Since addiction is a heterogeneous disease with many individually varying behavioral aspects that may be impacted by ELA, we next discuss common rodent assays of addiction-like behaviors. We then summarize the specific addiction-relevant behavioral phenotypes caused by ELA in male and female rodents and discuss some of the underlying changes in brain reward and stress circuits that are likely responsible. By better understanding the behavioral and neural mechanisms by which ELA promotes addiction vulnerability, we hope to facilitate development of new approaches for preventing or treating addiction in those with a history of ELA.

Early-life adversity and risk for depression and anxiety: The role of interpersonal support

Early-life adversity is a major risk factor for psychopathology, but not all who experience adversity develop psychopathology. The current study evaluated whether the links between child and adolescent adversity and depression and anxiety were described by general benefits and/or buffering effects of interpersonal support. Data from 456 adolescents oversampled on neuroticism over a 5-year period were examined in a series of discrete-time survival analyses to predict subsequent disorder onsets. Models examined linear, quadratic, and interactive effects of interpersonal support over time, as measured by chronic interpersonal stress interview ratings. Results did not support buffering effects of interpersonal support against either child or adolescent adversity in predicting depression or anxiety. However, there was support for the general benefits model of interpersonal support as evidenced by follow-up analyses of significant quadratic effects of interpersonal support, demonstrating that higher interpersonal support led to decreased likelihood of depression and anxiety onsets. Secondary analyses demonstrated that effects of interpersonal support remained after accounting for baseline depression and anxiety diagnoses. Further, quadratic effects were driven by social domains as opposed to familial domains when considering child adversity. Implications for interventions and randomized controlled prevention trials regarding interpersonal relationships are discussed.

Developmental administration of valproic acid alters DNA methylation and maternal behavior

Exposure to adversity in early development has powerful and potentially lasting consequences on behavior. Previous work in our laboratory using female Long-Evans rats has demonstrated that exposure to early-life maltreatment manifests into alterations in dam behavior, including a perpetuation of the maltreatment phenotype. These observed behavioral changes coincide with changes in epigenetic activity in the prefrontal cortex (PFC). Further, treating dams with a chromatin modifying agent (Zebularine) normalizes methylation and maltreatment phenotypes, suggesting a link between epigenetic programming and phenotypic outcomes. Here, we sought to investigate if administration of a chromatin modifying agent concurrent with the experience of maltreatment normalizes epigenetic activity associated with maltreatment and alters behavioral trajectories. Administration of valproic acid (VPA) transiently lowered levels of global DNA methylation in the PFC, regardless of exposure to nurturing care or maltreatment. When VPA-exposed animals reached adulthood, they engaged in more adverse behaviors toward their offspring. These data provide further evidence linking epigenetic changes in the developing brain with effects on behavior.

Developmental alterations of intestinal SGLT1 and GLUT2 induced by early weaning coincides with persistent low-grade metabolic inflammation in female pigs

Early-life adversity (ELA) is linked with the increased risk for inflammatory and metabolic diseases in later life, but the mechanisms remain poorly understood. Intestinal epithelial glucose transporters sodium-glucose-linked transporter 1 (SGLT1) and glucose transporter 2 (GLUT2) are the major route for intestinal glucose uptake but have also received increased attention as modulators of inflammatory and metabolic diseases. Here, we tested the hypothesis that early weaning (EW) in pigs, an established model of ELA, alters the development of epithelial glucose transporters and coincides with elevated markers of metabolic inflammation. The jejunum and ileum of 90-day-old pigs previously exposed to EW (16 days wean age), exhibited reduced SGLT1 activity (by ∼ 30%, P < 0.05) than late weaned (LW, 28 days wean age) controls. In contrast, GLUT2-mediated glucose transport was increased (P = 0.003) in EW pigs than in LW pigs. Reciprocal changes in SGLT1- and GLUT2-mediated transport coincided with transporter protein expression in the intestinal brush-border membranes (BBMs) that were observed at 90 days and 150 days of age. Ileal SGLT1-mediated glucose transport and BBM expression were inhibited by the β-adrenergic receptor (βAR) blocker propranolol in EW and LW pigs. In contrast, propranolol enhanced ileal GLUT2-mediated glucose transport (P = 0.015) and brush-border membrane vesicle (BBMV) abundance (P = 0.035) in LW pigs, but not in EW pigs. Early-weaned pigs exhibited chronically elevated blood glucose and C-reactive protein (CRP) levels, and adipocyte hypertrophy and upregulated adipogenesis-related gene expression in visceral adipose tissue. Altered development of intestinal glucose transporters by EW could underlie the increased risk for later life inflammatory and metabolic diseases.NEW & NOTEWORTHY These studies reveal that early-life adversity in the form of early weaning in pigs causes a developmental shift in intestinal glucose transport from SGLT1 toward GLUT2-mediated transport. Early weaning also induced markers of metabolic inflammation including persistent elevations in blood glucose and the inflammatory marker CRP, along with increased visceral adiposity. Altered intestinal glucose transport might contribute to increased risk for inflammatory and metabolic diseases associated with early-life adversity.

Glia-Driven Brain Circuit Refinement Is Altered by Early-Life Adversity: Behavioral Outcomes

Early-life adversity (ELA), often clinically referred to as "adverse childhood experiences (ACE)," is the exposure to stress-inducing events in childhood that can result in poor health outcomes. ELA negatively affects neurodevelopment in children and adolescents resulting in several behavioral deficits and increasing the risk of developing a myriad of neuropsychiatric disorders later in life. The neurobiological mechanisms by which ELA alters neurodevelopment in childhood have been the focus of numerous reviews. However, a comprehensive review of the mechanisms affecting adolescent neurodevelopment (i.e., synaptic pruning and myelination) is lacking. Synaptic pruning and myelination are glia-driven processes that are imperative for brain circuit refinement during the transition from adolescence to adulthood. Failure to optimize brain circuitry between key brain structures involved in learning and memory, such as the hippocampus and prefrontal cortex, leads to the emergence of maladaptive behaviors including increased anxiety or reduced executive function. As such, we review preclinical and clinical literature to explore the immediate and lasting effects of ELA on brain circuit development and refinement. Finally, we describe a number of therapeutic interventions best-suited to support adolescent neurodevelopment in children with a history of ELA.

Early-Life Adversity Leaves Its Imprint on the Oral Microbiome for More Than 20 Years and Is Associated with Long-Term Immune Changes

The early-life microbiome (ELM) interacts with the psychosocial environment, in particular during early-life adversity (ELA), defining life-long health trajectories. The ELM also plays a significant role in the maturation of the immune system. We hypothesised that, in this context, the resilience of the oral microbiomes, despite being composed of diverse and distinct communities, allows them to retain an imprint of the early environment. Using 16S amplicon sequencing on the EpiPath cohort, we demonstrate that ELA leaves an imprint on both the salivary and buccal oral microbiome 24 years after exposure to adversity. Furthermore, the changes in both communities were associated with increased activation, maturation, and senescence of both innate and adaptive immune cells, although the interaction was partly dependent on prior herpesviridae exposure and current smoking. Our data suggest the presence of multiple links between ELA, Immunosenescence, and cytotoxicity that occur through long-term changes in the microbiome.

Adverse Life Trajectories Are a Risk Factor for SARS-CoV-2 IgA Seropositivity

Asymptomatic individuals, called “silent spreaders” spread SARS-CoV-2 efficiently and have complicated control of the ongoing COVID-19 pandemic. As seen in previous influenza pandemics, socioeconomic and life-trajectory factors are important in disease progression and outcome. The demographics of the asymptomatic SARS-CoV-2 carriers are unknown. We used the CON-VINCE cohort of healthy, asymptomatic, and oligosymptomatic individuals that is statistically representative of the overall population of Luxembourg for age, gender, and residency to characterise this population. Gender (male), not smoking, and exposure to early-life or adult traumatic experiences increased the risk of IgA seropositivity, and the risk associated with early-life exposure was a dose-dependent metric, while some other known comorbidities of active COVID-19 do not impact it. As prior exposure to adversity is associated with negative psychobiological reactions to external stressors, we recorded psychological wellbeing during the study period. Exposure to traumatic events or concurrent autoimmune or rheumatic disease were associated with a worse evolution of anxiety and depressive symptoms throughout the lockdown period. The unique demographic profile of the “silent spreaders” highlights the role that the early-life period plays in determining our lifelong health trajectory and provides evidence that the developmental origins of health and disease is applicable to infectious diseases.

Elevated infant cortisol is necessary but not sufficient for transmission of environmental risk to infant social development: Cross-species evidence of mother-infant physiological social transmission

Environmental adversity increases child susceptibility to disrupted developmental outcomes, but the mechanisms by which adversity can shape development remain unclear. A translational cross-species approach was used to examine stress-mediated pathways by which poverty-related adversity can influence infant social development. Findings from a longitudinal sample of low-income mother-infant dyads indicated that infant cortisol (CORT) on its own did not mediate relations between early-life scarcity-adversity exposure and later infant behavior in a mother-child interaction task. However, maternal CORT through infant CORT served as a mediating pathway, even when controlling for parenting behavior. Findings using a rodent "scarcity-adversity" model indicated that pharmacologically blocking pup corticosterone (CORT, rodent equivalent to cortisol) in the presence of a stressed mother causally prevented social transmission of scarcity-adversity effects on pup social behavior. Furthermore, pharmacologically increasing pup CORT without the mother present was not sufficient to disrupt pup social behavior. Integration of our cross-species results suggests that elevated infant CORT may be necessary, but without elevated caregiver CORT, may not be sufficient in mediating the effects of environmental adversity on development. These findings underscore the importance of considering infant stress physiology in relation to the broader social context, including caregiver stress physiology, in research and interventional efforts.

Childhood exposure to hunger: associations with health outcomes in later life and epigenetic markers

Aim: To assess associations of early exposure to hunger with depressive symptoms and cardiovascular disease (CVD) and to investigate possible epigenetic pathways. Patients & methods: Data were based on a German population-based cohort of older adults (n = 9631). Regression models were performed for health outcomes in later life. An epigenome-wide association study for early-life exposure to hunger was performed in a subgroup (n = 2221) with whole blood DNA methylation data. Results: Childhood exposure to hunger was associated with CVD and depressive symptoms in later life. Prenatal or infant exposure was strongly associated with depressive symptoms. No CpG reached epigenome-wide significance after multiple testing correction. Conclusion: Childhood hunger is a risk factor for depressive symptoms and CVD at older age. DNA methylation could not explain this association.

Resilience and Stress in Later Life: A Network Analysis Approach Depicting Complex Interactions of Resilience Resources and Stress-Related Risk Factors in Older Adults

BACKGROUND

Emerging systemic approaches on resilience propose that a person's or group's adaptability to significant stress relies on a network of interdependent resources. However, little knowledge exists on systemic resilience in older survivors of early-life adversity (ELA) and how ELA affects their resource network in later life.

OBJECTIVE

This study investigated how ELA may be linked to the interplay of resources and stress-related risk factors in later life.

RESEARCH DESIGN AND METHODS

Data from N = 235 older adults (M age = 70.43 years; 46.40% female) were assessed. Half the participants were affected by ELA through compulsory social measures and placements in childhood, and/or adolescence ("risk group"). The other half were age-matched, non-affected participants ("control group"). Using psychometric instruments, a set of resilience-supporting resources in later life and current stress indices were assessed. Regularized partial correlation networks examined the interplay of resources in both groups, whilst also considering the impact of stress.

RESULTS

Both groups demonstrated only positive resource interrelations. Although the control group showed more possible resource connections, the groups did not significantly differ in the overall strength of connections. While group-specific resource interrelations were identified, self-esteem was observed to be the most important resource for the network interconnectedness of both groups. The risk group network showed a higher vulnerability to current stress.

DISCUSSION AND IMPLICATIONS

Network analysis is a useful approach in the examination of the complex interrelationships between resilience resources and stress-related risk factors in older adulthood.

Accelerated reproduction is not an adaptive response to early-life adversity in wild baboons

In humans and other long-lived species, harsh conditions in early life often lead to profound differences in adult life expectancy. In response, natural selection is expected to accelerate the timing and pace of reproduction in individuals who experience some forms of early-life adversity. However, the adaptive benefits of reproductive acceleration following early adversity remain untested. Here, we test a recent version of this theory, the internal predictive adaptive response (iPAR) model, by assessing whether accelerating reproduction following early-life adversity leads to higher lifetime reproductive success. We do so by leveraging 48 y of continuous, individual-based data from wild female baboons in the Amboseli ecosystem in Kenya, including prospective, longitudinal data on multiple sources of nutritional and psychosocial adversity in early life; reproductive pace; and lifetime reproductive success. We find that while early-life adversity led to dramatically shorter lifespans, individuals who experienced early adversity did not accelerate their reproduction compared with those who did not experience early adversity. Further, while accelerated reproduction predicted increased lifetime reproductive success overall, these benefits were not specific to females who experienced early-life adversity. Instead, females only benefited from reproductive acceleration if they also led long lives. Our results call into question the theory that accelerated reproduction is an adaptive response to both nutritional and psychosocial sources of early-life adversity in baboons and other long-lived species.

Early-Life Maternal Deprivation Predicts Stronger Sickness Behaviour and Reduced Immune Responses to Acute Endotoxaemia in a Pig Model

Early-life adversity may have programming effects on neuroendocrine and immune adaptation mechanisms in humans and socially living animals. Using a pig model, we investigated the effect of daily 2-h maternal and littermate deprivation from postnatal days 2–15, either alone (DA) or in a group of littermates (DG) on the neuroendocrine, immunological and behavioural responses of piglets challenged with the bacterial endotoxin lipopolysaccharide (LPS) on day 42. LPS increased plasma concentrations of cortisol, tumour necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and interleukin-10 (IL-10) and induced typical signs of sickness in all piglets. DA+DG piglets showed stronger signs of sickness compared to control (C) piglets. Plasma TNF-α concentrations were significantly lower in DA+DG males. In addition, the TNF-α/IL-10 ratio was significantly lower in DA than in DG and C males. Gene expression analyses showed lower hypothalamic TNF-α mRNA expression and diminished mRNA expression of the mineralocorticoid receptor (MR) and IL-10 in the amygdala of DA+DG piglets in response to LPS. Interestingly, males showed a higher MR- and a lower IL-10 mRNA expression in the amygdala than females. The present data suggest that repeated maternal deprivation during early life may alter neuroendocrine and immune responses to acute endotoxaemia in a sex-specific manner.

Catechol-O-methyltransferase Val158Met Genotype and Early-Life Family Adversity Interactively Affect Attention-Deficit Hyperactivity Symptoms Across Childhood

Attention-deficit hyperactivity disorder (ADHD) is among the most commonly diagnosed psychiatric disorders of childhood. The dopaminergic system has been shown to have substantial effects on its etiology, with both functional Catechol-O-methyltransferase (COMT) Val158Met genotype and early-life environmental adversity involved in the risk of inattention and hyperactivity/impulsivity symptoms. In this prospective longitudinal study, we examined for the first time the impact of proximal and distal early-life family adversity and COMT Val158Met polymorphism gene - both the direct and the interactive effects, on children's ADHD symptoms across childhood. Data came from the Family Life Project, a prospective longitudinal study of 1,292 children and families in high poverty from birth to 11 years. In infancy, data regarding socioeconomic (SES)-risk-factors, observed-caregiving behaviors, and DNA genotyping were collected. In early and middle childhood teachers rated the occurrence and severity of the child's ADHD symptoms. Multilevel growth curve models revealed independent effects of COMT, early-life SES-risk and negative caregiving on ADHD symptoms in early and middle childhood. Significant gene-environment interactions were found, indicating that overall, carriers of at least one COMT158Met allele were more sensitive to early-life adversity, showing higher inattention and hyperactivity/impulsivity symptoms severity in childhood when exposed to high SES-risk factors in infancy, compared to Val-Val carriers. Findings provide new insights into the complex etiology of ADHD and underline the need for further investigation of the neuronal mechanisms underlying gene-environment interactions. Findings might have implications for prevention and intervention strategies with a focus on early-life family relationships in genetically at-risk children.

Neonatal pain and reduced maternal care alter adult behavior and hypothalamic-pituitary-adrenal axis reactivity in a sex-specific manner

Preterm infants often spend a significant amount of time in the neonatal intensive care unit (NICU) where they are exposed to many stressors including pain and reduced maternal care. These early-life stressful experiences can have negative consequences on brain maturation during the neonatal period; however, less is known about the long-term cognitive and affective outcomes. Thus, this study was conducted to investigate the impact of neonatal pain and reduced maternal care on adult behavior and HPA axis reactivity in an animal model. Male and female rats underwent a series of repetitive needle pokes and/or reduced maternal care (through a novel tea ball infuser encapsulation method) during the first 4 days of life and were then assessed in a battery of behavioral tests as adults. We found that early-life pain enhanced spatial learning independent of the animal's sex, but altered HPA recovery from an acute stressor in females only. Moreover, reduced maternal care altered long-term spatial memory and reversal learning in males. These findings indicate that neonatal stressors have unique sex-dependent long-term biobehavioral effects in rodents. Continued examination of the behavioral consequences of these stressors may help explain varying vulnerability and resiliency in preterm infants who experienced early stress in the NICU.

Childhood adversity predicted suicidal ideation in older age: Results from a National Survey in Korea

Objectives: Suicide is a major mental health concern in South Korea, where a rapid increase in suicide rates among older adults is evident. This study aims to understand the association of childhood adversity with suicidal ideation in later life, and whether gender differences in the effects of childhood adversity exist.Method: The sample consisted of older adults aged 60 years and more in six waves of the Korea Welfare Panel Study from 2012 to 2017 (N = 4,105). A mixed effect logistic regression with random intercept was used to test the effects of childhood adversity on the risk of 12-month suicidal ideation.Results: After controlling for socioeconomic status, psychosocial resources, and health conditions, the mixed effect models using longitudinal data indicated that parental death predicted an increased risk of suicidal ideation and that a greater number of childhood adversities predicted a higher likelihood of suicidal ideation. No gender differences were found in the effects of childhood adversity on suicidal thoughts.Conclusion: These findings support a life course perspective, highlighting the importance of assessing early life disadvantages to understand suicidal ideation among older adults. The findings suggest that interventions targeting older adults who experienced parental death in childhood or multiple adversities may be effective in preventing suicidal ideation.

Maternal care of heterozygous dopamine receptor D4 knockout mice: Differential susceptibility to early-life rearing conditions

The differential susceptibility hypothesis proposes that individuals who are more susceptible to the negative effects of adverse rearing conditions may also benefit more from enriched environments. Evidence derived from human experiments suggests the lower efficacy dopamine receptor D4 (DRD4) 7‐repeat as a main factor in exhibiting these for better and for worse characteristics. However, human studies lack the genetic and environmental control offered by animal experiments, complicating assessment of causal relations. To study differential susceptibility in an animal model, we exposed Drd4^+/− mice and control litter mates to a limited nesting/bedding (LN), standard nesting (SN) or communal nesting (CN) rearing environment from postnatal day (P) 2‐14. Puberty onset was examined from P24 to P36 and adult females were assessed on maternal care towards their own offspring. In both males and females, LN reared mice showed a delay in puberty onset that was partly mediated by a reduction in body weight at weaning, irrespective of Drd4 genotype. During adulthood, LN reared females exhibited characteristics of poor maternal care, whereas dams reared in CN environments showed lower rates of unpredictability towards their own offspring. Differential susceptibility was observed only for licking/grooming levels of female offspring towards their litter; LN reared Drd4^+/− mice exhibited the lowest and CN reared Drd4^+/− mice the highest levels of licking/grooming. These results indicate that both genetic and early‐environmental factors play an important role in shaping maternal care of the offspring for better and for worse.

Early-life stress and inflammation: A systematic review of a key experimental approach in rodents

Repeated maternal separation is the most widely used pre-clinical approach to investigate the relationship between early-life chronic stress and its neuropsychiatric and physical consequences. In this systematic review, we identified 46 studies that conducted repeated maternal separation or single-episode maternal separation and reported measurements of interleukin-1b, interleukin-6, interleukin-10, tumour necrosis factor-alpha, or microglia activation and density. We report that in the short-term and in the context of later-life stress, repeated maternal separation has pro-inflammatory immune consequences in diverse tissues. Repeated maternal separation animals exhibit greater microglial activation and elevated pro-inflammatory cytokine signalling in key brain regions implicated in human psychiatric disorders. Notably, repeated maternal separation generally has no long-term effect on cytokine expression in any tissue in the absence of later-life stress. These observations suggest that the elevated inflammatory signalling that has been reported in humans with a history of early-life stress may be the joint consequence of ongoing stressor exposure together with potentiated neural and/or immune responsiveness to stressors. Finally, our findings provide detailed guidance for future studies interrogating the causal roles of early-life stress and inflammation in disorders such as major depression.

Enhancing Executive Functions Through Social Interactions: Causal Evidence Using a Cross-Species Model

It has long been theorized that humans develop higher mental functions, such as executive functions (EFs), within the context of interpersonal interactions and social relationships. Various components of social interactions, such as interpersonal communication, perspective taking, and conforming/adhering to social rules, may create important (and perhaps even necessary) opportunities for the acquisition and continued practice of EF skills. Furthermore, positive and stable relationships facilitate the development and maintenance of EFs across the lifespan. However, experimental studies investigating the extent to which social experiences contribute causally to the development of EFs are lacking. Here, we present experimental evidence that social experiences and the acquisition of social skills influence the development of EFs. Specifically, using a rat model, we demonstrate that following exposure to early-life adversity, a socialization intervention causally improves working memory in peri-adolescence. Our findings combined with the broader literature promote the importance of cultivating social skills in support of EF development and maintenance across the lifespan. Additionally, cross-species research will provide insight into causal mechanisms by which social experiences influence cognitive development and contribute to the development of biologically sensitive interventions.

Early-life adversity-induced long-term epigenetic programming associated with early onset of chronic physical aggression: Studies in humans and animals

Objectives: To examine whether chronic physical aggression (CPA) in adulthood can be epigenetically programmed early in life due to exposure to early-life adversity. Methods: Literature search of public databases such as PubMed/MEDLINE and Scopus. Results: Children/adolescents susceptible for CPA and exposed to early-life abuse fail to efficiently cope with stress that in turn results in the development of CPA later in life. This phenomenon was observed in humans and animal models of aggression. The susceptibility to aggression is a complex trait that is regulated by the interaction between environmental and genetic factors. Epigenetic mechanisms mediate this interaction. Subjects exposed to stress early in life exhibited long-term epigenetic programming that can influence their behaviour in adulthood. This programming affects expression of many genes not only in the brain but also in other systems such as neuroendocrine and immune. Conclusions: The propensity to adult CPA behaviour in subjects experienced to early-life adversity is mediated by epigenetic programming that involves long-term systemic epigenetic alterations in a whole genome.

The paradox of care in behavioral epigenetics: Constructing early-life adversity in the lab

Many epigenetic studies focus on how stress, trauma, and care become molecularly embodied, affect gene expression without changing DNA sequence, and produce changes that influence the health and behavior of individuals, their offspring, and future generations. This article describes how care has become central in research on the epigenetic effects of early-life adversity. My analysis draws on two years of ethnographic research in a behavioral epigenetics laboratory in the United States. Building on traditions in feminist theory and the sociology of science, I document how care is enacted with research samples, experimental protocols, and behavioral endpoints in experiments with model organisms. My findings point to tensions between researchers' care for the data and their measurement of adversity as a discrete variable in the form of maternal interaction, neglect, and abuse. I argue that these tensions suggest a "paradox of care" that is actively shaping how epigenetic knowledge is produced and its impacts in society. My analysis shows how decisions in the lab are shaping new understandings of how early-life experiences influence health, with significant impacts on our expectations of mothers and pregnant women. This study suggests that the more complex explanations of health and development promised by epigenetics are simultaneously constructed and constrained by caring practices in the laboratory.

Metabolic dysfunction in a rat model of early-life scarcity-adversity: Modulatory role of cafeteria diet

NEW FINDINGS

What is the central question of this study? Early-life adversity is associated with increased risk for obesity and metabolic dysfunction. However, it is unclear whether obesity and metabolic dysfunction result from coping strategies to deal with adversity-related emotional dysregulation, a direct programming of systems regulating metabolic function, or a combination of both. What is the main finding and its importance? Early-life adversity increases vulnerability to later-life obesity and metabolic dysfunction, indicating that genetics and adult lifestyle are not the only determinants of obesity and related metabolic dysfunction. Moreover, consumption of cafeteria diet exacerbated metabolic dysfunction associated with early-life adversity, suggesting that poor dietary choices might have a bigger impact in the context of early-life adversity.

ABSTRACT

Early-life adversity has become recognized as an important factor contributing to adult obesity and associated metabolic dysfunction. However, it is unclear whether obesity and metabolic dysfunction associated with early-life adversity result from coping strategies to deal with adversity-related emotional dysregulation, a direct programming of systems regulating metabolic function, or a combination. Interestingly, both early-life adversity and later-life dietary choices affect immune function, favouring pro-inflammatory mechanisms that are associated with obesity-related metabolic dysfunction. To investigate the unique and/or interactive effects of early-life adversity and later-life dietary choices for increased vulnerability to obesity and metabolic dysfunction, and specifically the role of the immune system in this vulnerability, we combined a naturalistic rat model of early-life scarcity-adversity with a rat model of obesity, the cafeteria diet. Our results indicate that early-life adversity alone induces insulin resistance, reduces pancreatic insulin secretion, plasma concentrations of triglycerides and cholesterol, and increases fasting glucose and tumour necrosis factor-α plasma concentrations. Importantly, animals exposed to adverse rearing were more vulnerable to metabolic dysregulation associated with the cafeteria diet, given that they consumed more energy, showed more severe hepatic steatosis and increased concentrations of the pro-inflammatory cytokine interleukin-1β than normally reared animals fed the cafeteria diet. Together, our results suggest that early-life adversity negatively programmes physiological systems that regulate metabolic function and increases vulnerability to obesity and metabolic dysfunction in adulthood. These results highlight the intrinsic relationship between the quality of the early postnatal environment and later-life dietary choices on adult health outcomes.

Socioeconomic Risk and School Readiness: Longitudinal Mediation Through Children's Social Competence and Executive Function

The association of socioeconomic status with academic readiness and school achievement is well established. However, the specific contributions of cognitive and social aspects of self-regulation, and potential reciprocal relations between them in the prediction of school readiness and early school achievement have not previously been examined. This study examined mediational processes involving children's executive function (EF) skills at 58 months and Grade 1 (G1) and social competence in Kindergarten (K) and G1, as potential pathways by which early-life poverty-related risks influence Grade 2 (G2) math and reading achievement. Data came from the Family Life Project, which is a prospective longitudinal study of 1,292 children and families followed from birth in primarily low-income, non-urban counties in Pennsylvania (PA) and North Carolina (NC). Autoregressive cross-lagged mediation analyses indicated that EF at 58 months through EF at G1 mediated negative associations between cumulative risk exposure and academic skills, with this pathway mediating 36% of the total effect. Furthermore, social competence at K through EF at G1 mediated negative associations between early-life cumulative socioeconomic risk and academic skills, mediating 16% of the total effect. These findings provide evidence that poverty-related risks can influence school readiness and academic achievement via EF. Additionally, these results provide preliminary support for the premise that social competence through EF is a pathway by which cumulative poverty-related risk predicts early academic competence. Our findings are consistent with studies demonstrating developmental associations between EF and social competence. Furthermore, our findings are consistent with prekindergarten programs for children in poverty that emphasize both cognitive and social aspects of self-regulation.

Early-life begging effort reduces adult body mass but strengthens behavioural defence of the rate of energy intake in European starlings

Animals require strategies for coping with periods when food is scarce. Such strategies include storing fat as a buffer, and defending the rate of energy intake by changing foraging behaviour when food becomes difficult to obtain. Storage and behavioural defence may constitute alternative strategies for solving the same problem. We would thus expect any developmental influences that limit fat storage in adulthood to also induce a compensatory alteration in adult foraging behaviour, specifically when food is hard to obtain. In a cohort of hand-reared European starlings, we found that higher manipulated early-life begging effort caused individuals to maintain consistently lower adult body mass over a period of two years. Using an operant foraging task in which we systematically varied the costs of obtaining food, we show that higher early-life begging effort also caused stronger behavioural defence of the rate of energy intake when food was more costly to obtain. Among individuals with the same developmental history, however, those individuals who defended their rate of energy intake most strongly were also the heaviest. Our results are relevant to understanding why there are marked differences in body weight and foraging behaviour even among individuals inhabiting the same environment.

Early-Life Stress Does Not Aggravate Spatial Memory or the Process of Hippocampal Neurogenesis in Adult and Middle-Aged APP/PS1 Mice

Life-time experiences are thought to influence the risk to develop the neurodegenerative disorder Alzheimer’s disease (AD). In particular, early-life stress (ES) may modulate the onset and progression of AD. There is recent evidence by our group and others that AD-related neuropathological progression and the associated neuroimmune responses are modulated by ES in the classic APPswe/PS1dE9 mouse model for AD. We here extend our previous study on ES mediated modulation of neuropathology and neuroinflammation and address in the same cohort of mice whether ES accelerates and/or aggravates AD-induced cognitive decline and alterations in the process of adult hippocampal neurogenesis (AHN), a form of brain plasticity. Chronic ES was induced by limiting bedding and nesting material during the first postnatal week and is known to induce cognitive deficits by 4 months in wild type (WT) mice. The onset of cognitive decline in APP/PS1 mice generally starts around 6 months of age. We here tested mice at ages 2–4 months to study acceleration and at ages 8–10 months for aggravation of the APP/PS1 phenotype. ES-exposed WT and APP/PS1 mice were able to perform the object recognition (ORT) and location tasks (OLT) at 2 months of age. Interestingly, at 3 months, ES induced impairments in the performance of the OLT in WT, but not in APP/PS1 mice. APP/PS1 mice exhibited alterations in hippocampal cell proliferation and differentiation, but ES exposure did not further change this. At 9 months, APP/PS1 mice exhibited impaired performance in the Morris Water Maze (MWM) task, as well as reductions in markers of the AHN process, which were not further modulated by ES exposure. In addition, we observed a so far unreported hyperactivity in ES-exposed mice at 8 months of age, which hampered assessment of cognitive functions in the ORT and OLT. In conclusion, while ES has been reported to modulate AD neuropathology and neuroinflammation before, it failed to accelerate or aggravate the decline in cognition or the process of AHN in APP/PS1 mice at ages 2–4 and 8–10 months. Future studies are needed to unravel how ES might affect the vulnerability to develop AD.

Effects of early-life competition and maternal nutrition on telomere lengths in wild meerkats

Early-life adversity can affect health, survival and fitness later in life, and recent evidence suggests that telomere attrition may link early conditions with their delayed consequences. Here, we investigate the link between early-life competition and telomere length in wild meerkats. Our results show that, when multiple females breed concurrently, increases in the number of pups in the group are associated with shorter telomeres in pups. Given that pups from different litters compete for access to milk, we tested whether this effect is due to nutritional constraints on maternal milk production, by experimentally supplementing females' diets during gestation and lactation. While control pups facing high competition had shorter telomeres, the negative effects of pup number on telomere lengths were absent when maternal nutrition was experimentally improved. Shortened pup telomeres were associated with reduced survival to adulthood, suggesting that early-life competition for nutrition has detrimental fitness consequences that are reflected in telomere lengths. Dominant females commonly kill pups born to subordinates, thereby reducing competition and increasing growth rates of their own pups. Our work suggests that an additional benefit of infanticide may be that it also reduces telomere shortening caused by competition for resources, with associated benefits for offspring ageing profiles and longevity.

Resting high-frequency heart rate variability moderates the association between early-life adversity and body adiposity

This study investigates resting high-frequency heart rate variability as a moderator of the association between early-life adversity and two measures of body adiposity. Data were collected from 149 young adults attending a large university in the Midwestern United States (M_age = 18.8 years; 45% black; 55% white; 56% female). Self-reported early-life adversity was associated with greater waist-to-height ratio and body mass index. The strength of these associations was moderated by high-frequency heart rate variability, such that the link was stronger for individuals with lower heart rate variability. Resting high-frequency heart rate variability thus has potential health significance as a biomarker of stress vulnerability.

A marker of biological age explains individual variation in the strength of the adult stress response

The acute stress response functions to prioritize behavioural and physiological processes that maximize survival in the face of immediate threat. There is variation between individuals in the strength of the adult stress response that is of interest in both evolutionary biology and medicine. Age is an established source of this variation-stress responsiveness diminishes with increasing age in a range of species-but unexplained variation remains. Since individuals of the same chronological age may differ markedly in their pace of biological ageing, we asked whether biological age-measured here via erythrocyte telomere length-predicts variation in stress responsiveness in adult animals of the same chronological age. We studied two cohorts of European starlings in which we had previously manipulated the rate of biological ageing by experimentally altering the competition experienced by chicks in the fortnight following hatching. We predicted that individuals with greater developmental telomere attrition, and hence greater biological age, would show an attenuated corticosterone (CORT) response to an acute stressor when tested as adults. In both cohorts, we found that birds with greater developmental telomere attrition had lower peak CORT levels and a more negative change in CORT levels between 15 and 30 min following stress exposure. Our results, therefore, provide strong evidence that a measure of biological age explains individual variation in stress responsiveness: birds that were biologically older were less stress responsive. Our results provide a novel explanation for the phenomenon of developmental programming of the stress response: observed changes in stress physiology as a result of exposure to early-life adversity may reflect changes in ageing.

Early-Life Socioeconomic Disadvantage and Metabolic Health Disparities

OBJECTIVE

A quarter of the world's population have metabolic syndrome (MetS). MetS prevalence is stratified by socioeconomic status (SES), such that low SES is associated with higher MetS risk. The present study examined the relative roles of early-life SES and current SES in explaining MetS risk.

METHODS

Participants (N = 354; ages = 15-55 years, M [SD] = 36.5 [10.7] years; 55% female; 72.9% white, 16.9% Asian, 10.2% others) were evaluated for SES and MetS. All were in good health, defined as free of chronic medical illness and acute infectious disease. Using occupational status as a proxy for SES, we recruited roughly equal numbers of participants with low-low, low-high, high-low, and high-high combinations of early-life and current SES. We used the International Diabetes Federation definition for MetS using race- and sex-specific cutoffs for waist circumference, triglyceride levels, high-density lipoprotein cholesterol, blood pressure, and glycosylated hemoglobin levels.

RESULTS

Analyses revealed a main effect of low early-life SES on increased MetS risk according to the three separate definitions. They included the traditional MetS diagnosis (odds ratio [OR] = 1.53, confidence interval [CI] = 1.01-2.33, p = .044), the number of MetS components for which diagnostic thresholds were met (OR = 1.61, CI = 1.10-2.38, p = .015), and a continuous indicator of metabolic risk based on factor analysis (F(1,350) = 6.71, p = .010, partial η = .019). There was also a significant interaction of early-life SES and current SES in predicting MetS diagnosis (OR = 1.54, CI = 1.02-2.34). The main effects of current SES were nonsignificant in all analyses.

CONCLUSIONS

These findings suggest that MetS health disparities originate in childhood, which may be an opportune period for interventions.

Sex-specific impact of early-life adversity on chronic pain: a large population-based study in Japan

BACKGROUND

Responses to early-life adversity may differ by sex. We investigated the sex-specific impact of early-life adversity on chronic pain, chronic multisite pain, and somatizing tendency with chronic pain.

METHODS

We examined 4229 respondents aged 20-79 years who participated in the Pain Associated Cross-Sectional Epidemiological Survey in Japan. Outcomes were: 1) chronic pain prevalence, 2) multisite pain (≥3 sites) prevalence, and 3) multiple somatic symptoms (≥3 symptoms) among respondents with chronic pain related to the presence or absence of early-life adversity. Multivariable-adjusted odds ratios (ORs) were calculated with 95% confidence intervals using a logistic regression model including age, smoking status, exercise routine, sleep time, body mass index, household expenditure, and the full distribution of scores on the Mental Health Inventory-5. We further adjusted for pain intensity when we analyzed the data for respondents with chronic pain.

RESULTS

The prevalence of chronic pain was higher among respondents reporting the presence of early-life adversity compared with those reporting its absence, with multivariable ORs of 1.62 (1.22-2.15, p<0.01) in men and 1.47 (1.13-1.90, p<0.01) in women. Among women with chronic pain, early-life adversity was associated with multisite pain and multiple somatic symptoms; multivariable ORs were 1.78 (1.22-2.60, p<0.01) for multisite pain and 1.89 (1.27-2.83, p<0.01) for ≥3 somatic symptoms. No associations were observed between early-life adversity and chronic multisite pain or multiple somatic symptoms among men with chronic pain.

CONCLUSION

Early-life adversity may be linked to a higher prevalence of chronic pain among both sexes and to multisite pain and somatizing tendency among women with chronic pain.

Neonatal pain and reduced maternal care: Early-life stressors interacting to impact brain and behavioral development

Advances in neonatal intensive care units (NICUs) have drastically increased the survival chances of preterm infants. However, preterm infants are still exposed to a wide range of stressors during their stay in the NICU, which include painful procedures and reduced maternal contact. The activation of the hypothalamic-pituitary-adrenal (HPA) axis, in response to these stressors during this critical period of brain development, has been associated with many acute and long-term adverse biobehavioral outcomes. Recent research has shown that Kangaroo care, a non-pharmacological analgesic based on increased skin-to-skin contact between the neonate and the mother, negates the adverse outcomes associated with neonatal pain and reduced maternal care, however the biological mechanism remains widely unknown. This review summarizes findings from both human and rodent literature investigating neonatal pain and reduced maternal care independently, primarily focusing on the role of the HPA axis and biobehavioral outcomes. The physiological and positive outcomes of Kangaroo care will also be discussed in terms of how dampening of the HPA axis response to neonatal pain and increased maternal care may account for positive outcomes associated with Kangaroo care.

Investigating epigenetic consequences of early-life adversity: some methodological considerations

Stressful and traumatic events occurring during early childhood have been consistently associated with the development of psychiatric disorders later in life. This relationship may be mediated in part by epigenetic mechanisms, such as DNA methylation, which are influenced by the early-life environment. Epigenetic patterns can have lifelong effects on gene expression and on the functioning of biological processes relevant to stress reactivity and psychopathology. Optimization of epigenetic research activity necessitates a discussion surrounding the methodologies used for DNA methylation analysis, selection of tissue sources, and timing of psychological and biological assessments. Recent studies related to early-life adversity and methylation, including both candidate gene and epigenome-wide association studies, have drawn from the variety of available techniques to generate interesting data in the field. Further discussion is warranted to address the limitations inherent to this field of research, along with future directions for epigenetic studies of adversity-related psychopathology.

Lymphoblastoid cell lines reveal associations of adult DNA methylation with childhood and current adversity that are distinct from whole blood associations

BACKGROUND

Some cohort studies bank lymphoblastoid cell lines (LCLs) as a renewable source of participant DNA. However, although LCL DNA has proved valuable for genetic studies, its utility in epigenetic epidemiology research is unknown.

METHODS

To assess whether LCL DNA can be used for life-course environmental epigenomics, we carried out a pilot methylomic study (using the Illumina Infinium Human Methylation 450 BeadChip) of nil-passage, Epstein-Barr virus (EBV)-transformed LCLs (n = 42) and 28 matched whole-blood (WB) samples. These were from adult male participants of the British 1958 birth cohort, selected for extremes of social economic position (SEP) in childhood and adulthood, with additional information available on childhood abuse and prenatal tobacco exposure.

RESULTS

We identified a small number of weak associations between these exposures and methylation levels of both individual CpG sites and genomic regions in WB and LCLs. However, only one of the regional, and none of the individual CpG site associations were common to both sample types. The lack of overlap between the associations detected in LCL compared with those found in WB could either be due to the EBV-transformation process, or to the fact that, unlike WB, LCLs are essentially a single (CD19+) cell type. We provide evidence that the latter is the more potent explanation, by showing that CpG sites known to be differentially methylated between different types of blood cell have significantly lower correlations (R = 0.11) than average (R = 0.2) between WB and LCLs in our datasets, whereas sites known to be affected by EBV-transformation have significantly higher correlations (R = 0.3).

CONCLUSIONS

This small pilot study suggests that the DNA methylation profile of LCLs is more closely related to that of B cells than WB and, additionally, that LCLs may nevertheless be useful for life-course environmental epigenomics.

Early-life adversity and adolescent depression: mechanisms involving the ventral striatum

Early-life adversity is a well-established risk factor for the development of depression later in life. Here we discuss the relationship between early-life adversity and depression, focusing specifically on effects of early-life caregiver deprivation on alterations in the neural and behavioral substrates of reward-processing. We also examine vulnerability to depression within the context of sensitive periods of neural development and the timing of adverse exposure. We further review the development of the ventral striatum, a limbic structure implicated in reward processing, and its role in depressive outcomes following early-life adversity. Finally, we suggest a potential neurobiological mechanism linking early-life adversity and altered ventral striatal development. Together these findings may help provide further insight into the role of reward circuitry dysfunction in psychopathological outcomes in both clinical and developmental populations.

An experimental demonstration that early-life competitive disadvantage accelerates telomere loss

Adverse experiences in early life can exert powerful delayed effects on adult survival and health. Telomere attrition is a potentially important mechanism in such effects. One source of early-life adversity is the stress caused by competitive disadvantage. Although previous avian experiments suggest that competitive disadvantage may accelerate telomere attrition, they do not clearly isolate the effects of competitive disadvantage from other sources of variation. Here, we present data from an experiment in European starlings (Sturnus vulgaris) that used cross-fostering to expose siblings to divergent early experience. Birds were assigned either to competitive advantage (being larger than their brood competitors) or competitive disadvantage (being smaller than their brood competitors) between days 3 and 12 post-hatching. Disadvantage did not affect weight gain, but it increased telomere attrition, leading to shorter telomere length in disadvantaged birds by day 12. There were no effects of disadvantage on oxidative damage as measured by plasma lipid peroxidation. We thus found strong evidence that early-life competitive disadvantage can accelerate telomere loss. This could lead to faster age-related deterioration and poorer health in later life.