Biocultural and social determinants of ill health and early mortality in a New Mexican paediatric autopsy sample

RESULTS.

Hispanic children have higher odds of growth stunting than non-Hispanic White children. Native American children die younger and have higher odds of respiratory diseases and porous lesions than Hispanic and non-Hispanic Whites. Rural/urban location does not significantly impact age at death, but housing type does. Individuals who lived in trailers/mobile homes had earlier ages at death. When intersections between housing type and housing location are considered, children who were poor and from impoverished areas lived longer than those who were poor from relatively well-off areas.

CONCLUSIONS.

Children's health is shaped by factors outside their control. The children included in this study embodied experiences of social and ELS and did not survive to adulthood. They provide the most sobering example of the harm that social factors (structural racism/discrimination, socioeconomic, and political structures) can inflict.

Dissecting the Long-Term Effect of Stress Early in Life on FKBP5: The Role of miR-20b-5p and miR-29c-3p

Exposure to early-life stress (ELS) has been related to an increased susceptibility to psychiatric disorders later in life. Although the molecular mechanisms underlying this association are still under investigation, glucocorticoid signaling has been proposed to be a key mediator. Here, we used two preclinical models, the prenatal stress (PNS) animal model and an in vitro model of hippocampal progenitor cells, to assess the long-term effect of ELS on FKBP5, NR3C1, NR3C2, and FoxO1, four stress-responsive genes involved in the effects of glucocorticoids. In the hippocampus of male PNS rats sacrificed at different time points during neurodevelopment (PND 21, 40, 62), we found a statistically significant up-regulation of FKBP5 at PND 40 and PND 62 and a significant increase in FoxO1 at PND 62. Interestingly, all four genes were significantly up-regulated in differentiated cells treated with cortisol during cell proliferation. As FKBP5 was consistently modulated by PNS at adolescence (PND 40) and adulthood (PND 62) and by cortisol treatment after cell differentiation, we measured a panel of miRNAs targeting FKBP5 in the same samples where FKBP5 expression levels were available. Interestingly, both miR-20b-5p and miR-29c-3p were significantly reduced in PNS-exposed animals (both at PND40 and 62) and also in the in vitro model after cortisol exposure. Our results highlight the key role of miR-20b-5p and miR-29c-3p in sustaining the long-term effects of ELS on the stress response system, representing a mechanistic link possibly contributing to the enhanced stress-related vulnerability to mental disorders.

Adverse effects of early-life stress: focus on the rodent neuroendocrine system

Early-life stress is associated with a high prevalence of mental illnesses such as post-traumatic stress disorders, attention-deficit/hyperactivity disorder, schizophrenia, and anxiety or depressive behavior, which constitute major public health problems. In the early stages of brain development after birth, events such as synaptogenesis, neuron maturation, and glial differentiation occur in a highly orchestrated manner, and external stress can cause adverse long-term effects throughout life. Our body utilizes multifaceted mechanisms, including neuroendocrine and neurotransmitter signaling pathways, to appropriately process external stress. Newborn individuals first exposed to early-life stress deploy neurogenesis as a stress-defense mechanism; however, in adulthood, early-life stress induces apoptosis of mature neurons, activation of immune responses, and reduction of neurotrophic factors, leading to anxiety, depression, and cognitive and memory dysfunction. This process involves the hypothalamus-pituitary-adrenal axis and neurotransmitters secreted by the central nervous system, including norepinephrine, dopamine, and serotonin. The rodent early-life stress model is generally used to experimentally assess the effects of stress during neurodevelopment. This paper reviews the use of the early-life stress model and stress response mechanisms of the body and discusses the experimental results regarding how early-life stress mediates stress-related pathways at a high vulnerability of psychiatric disorder in adulthood.

Effects of Pre- and Postnatal Early-Life Stress on Internalizing, Adiposity, and Their Comorbidity

OBJECTIVE

Depression and obesity are 2 highly prevalent and often comorbid conditions. Exposure to early-life stress (ELS) has been associated with both depression and obesity in adulthood, as well as their preclinical manifestations during development. However, it remains unclear whether (1) associations differ depending on the timing of stress exposure (prenatal vs postnatal), and whether (2) ELS is a shared risk factor underlying the comorbidity between the 2 conditions.

METHOD

Leveraging data from 2 large population-based birth cohorts (ALSPAC: n = 8,428 [52% male participants]; Generation R: n = 4,268 [48% male participants]), we constructed comprehensive cumulative measures of prenatal (in utero) and postnatal (from birth to 10 years) ELS. At age 13.5 years, we assessed the following: internalizing symptoms (using maternal reports); fat mass percentage (using dual-energy X-ray absorptiometry); and their comorbidity, defined as the co-occurrence of high internalizing and high adiposity.

RESULTS

Both prenatal (total effect [95% CI] = 0.20 [0.16; 0.22]) and postnatal stress (β [95%CI] = 0.22 [0.17; 0.25]) were associated with higher internalizing symptoms, with evidence of a more prominent role of postnatal stress. A weaker association (driven primarily by prenatal stress) was observed between stress and adiposity (prenatal: 0.07 [0.05; 0.09]; postnatal: 0.04 [0.01; 0.07]). Both prenatal (odds ratio [95%CI] = 1.70 [1.47; 1.97]) and postnatal (1.87 [1.61; 2.17]) stress were associated with an increased risk of developing comorbidity.

CONCLUSION

We found evidence of timing and shared causal effects of ELS on psycho-cardiometabolic health in adolescence; however, future research is warranted to clarify how these associations may unfold over time.

DIVERSITY & INCLUSION STATEMENT

We worked to ensure sex and gender balance in the recruitment of human participants. We worked to ensure race, ethnic, and/or other types of diversity in the recruitment of human participants. We worked to ensure that the study questionnaires were prepared in an inclusive way. One or more of the authors of this paper self-identifies as a member of one or more historically underrepresented racial and/or ethnic groups in science. One or more of the authors of this paper self-identifies as a member of one or more historically underrepresented sexual and/or gender groups in science. We actively worked to promote sex and gender balance in our author group.

Developmental Neuroendocrinology of Early-Life Stress: Impact on Child Development and Behavior

Our internal balance, or homeostasis, is threatened or perceived as threatened by stressful stimuli, the stressors. The stress system is a highly conserved system that adjusts homeostasis to the resting state. Through the concurrent activation of the hypothalamic-pituitary-adrenal axis and the locus coeruleus/norepinephrine-autonomic nervous systems, the stress system provides the appropriate physical and behavioral responses, collectively termed as "stress response", to restore homeostasis. If the stress response is prolonged, excessive or even inadequate, several acute or chronic stress-related pathologic conditions may develop in childhood, adolescence and adult life. On the other hand, earlylife exposure to stressors has been recognized as a major contributing factor underlying the pathogenesis of non-communicable disorders, including neurodevelopmental disorders. Accumulating evidence suggests that early-life stress has been associated with an increased risk for attention deficit hyperactivity disorder and autism spectrum disorder in the offspring, although findings are still controversial. Nevertheless, at the molecular level, early-life stressors alter the chemical structure of cytosines located in the regulatory regions of genes, mostly through the addition of methyl groups. These epigenetic modifications result in the suppression of gene expression without changing the DNA sequence. In addition to DNA methylation, several lines of evidence support the role of non-coding RNAs in the evolving field of epigenetics. In this review article, we present the anatomical and functional components of the stress system, discuss the proper, in terms of quality and quantity, stress response, and provide an update on the impact of early-life stress on child development and behavior.

The long-term impact of early adverse experience on adaptive functioning: a pilot study integrating measures of mental status, nonverbal communication, and heart rate variability

Background: Childhood maltreatment (CM) can disrupt the development of behavioural and physiological systems, increasing the risk of physical and psychological adverse outcomes across the lifespan. CM may cause interpersonal dysfunctions that impair social communication and lead to dysfunctional activation of the autonomic nervous system. The present exploratory study analyzed the long-term impact of CM from an integrated perspective through the simultaneous assessment of psychological symptoms, social and behavioural communication, and physiological regulation.

Methods: Participants were 55 healthy university students (9 males and 46 females; mean age ± SD = 25.26 ± 2.83 years), who filled out a battery of questionnaires to assess the presence of CM (Childhood Trauma Questionnaire) and psychopathological symptoms (Symptom Check-List-90 Item Revised). Participants were then subjected to a videotaped interview for the assessment of non-verbal behaviour (Ethological Coding System for Interviews) and measurement of tonic heart rate variability (HRV), a measure of physiological adaptability to the environment. We performed Pearson's correlation analysis to evaluate the associations between non-verbal behaviour, HRV, and CM variables. Multiple regression analysis was used to evaluate the independent associations between CM variables on HRV and nonverbal behaviour.

Results: We found an association between more severe CM, increased symptoms-related distress (ps < .001), less submissive behaviour (ps < .018), and decreased tonic HRV (ps < .028). As a result of multiple regression analysis, participants with a history of emotional abuse (R² = .18, p = .002) and neglect (R² = .10, p = .03) were more likely to display decreased submissive behaviour during the dyadic interview. Moreover, early experience of emotional (R² = .21, p = .005) and sexual abuse (R² = .14, p = .04) was associated with decreased tonic HRV.

Conclusion: Our preliminary findings show the utility of analyzing the long-term effects of adverse early experiences at different levels of ‘adaptive functioning’ (the capabilities needed to respond effectively to environmental demands).

Substantial traumatic experiences during childhood, such as emotional abuse, emotional neglect, and sexual abuse were associated with lower heart rate variability levels in a sample of young adults.

Young adults with a history of emotional abuse and neglect were more likely to display decreased submissive behaviour (ethological behaviour) during the dyadic interview.

Severe childhood maltreatment was associated with increased symptoms-related distress, less submissive behaviour (ethological behaviour), and decreased tonic heart rate variability in young adults.

Paraventricular Mast Cell-Derived Histamine Activates CRH Neurons to Mediate Adult Visceral Hypersensitivity Induced by Neonatal Maternal Separation

Neonatal maternal separation (NMS) is an early-life stress (ELS) that can result in adult visceral hypersensitivity, which is usually manifested as chronic visceral pain. Although mast cells and corticotropin-releasing hormone (CRH) neurons are involved in stress response, whether there is an interaction between mast cells and CRH neurons in hypothalamic paraventricular nucleus (PVN) during the ELS-induced visceral hypersensitivity remains elusive. Herein, we established an NMS model by separating neonatal mice from their mothers, and observed that these mice presented visceral hypersensitivity in adulthood, as indicated by elevated abdominal withdrawal reflex and lowered visceral pain threshold. The NMS-induced adult visceral hypersensitivity was accompanied by activation of mast cells and CRH neurons in PVN. Also, NMS increased the histamine content (an inflammatory mediator mainly released by mast cells) and histamine H2 receptor (H2R) expression of CRH neurons in PVN. Remarkably, intra-PVN administration with mast cell stabilizer attenuated the NMS-induced CRH neuronal activation and adult visceral pain, while histamine administration showed the opposite effects. Moreover, intra-PVN injection with H2R antagonist alleviated the NMS-induced CRH neuronal activation, PKA and CREB phosphorylation, and importantly, adult visceral pain. Together, our findings revealed a role of an interaction between paraventricular mast cells and CRH neurons in NMS-induced adult visceral hypersensitivity, thereby providing a perspective for the management of visceral pain.

Site-specific pathophysiology in a neonatal mouse model of gastroparesis

BACKGROUND

Early-life events impact maturation of the gut microbiome, enteric nervous system, and gastrointestinal motility. We examined three regions of gastric tissue to determine how maternal separation and gut microbes influence the structure and motor function of specific regions of the neonatal mouse stomach.

METHODS

Germ-free and conventionally housed C57BL/6J mouse pups underwent timed maternal separation (TmSep) or nursed uninterrupted (controls) until 14 days of life. We assessed gastric emptying by quantifying the progression of gavaged fluorescein isothiocyanate (FITC)-dextran. With isolated rings of forestomach, corpus, and antrum, we measured tone and contractility by force transduction, gastric wall thickness by light microscopy, and myenteric plexus neurochemistry by whole-mount immunostaining.

KEY RESULTS

Regional gastric sampling revealed site-specific differences in contractile patterns and myenteric plexus structure. In neonatal mice, TmSep prolonged gastric emptying. In the forestomach, TmSep increased contractile responses to carbachol, decreased muscularis externa and mucosa thickness, and increased the relative proportion of myenteric plexus nNOS+ neurons. Germ-free conditions did not appreciably alter the structure or function of the neonatal mouse stomach and did not impact the changes caused by TmSep.

CONCLUSIONS AND INFERENCES

A regional sampling approach facilitates site-specific investigations of murine gastric motor physiology and histology to identify site-specific alterations that may impact gastrointestinal function. Delayed gastric emptying in TmSep is associated with a thinner muscle wall, exaggerated cholinergic contractile responses, and increased proportions of inhibitory myenteric plexus nNOS+ neurons in the forestomach. Gut microbes do not profoundly affect the development of the neonatal mouse stomach or the gastric pathophysiology that results from TmSep.

Communal nesting differentially attenuates the impact of pre-weaning social isolation on behavior in male and female rats during adolescence and adulthood

Introduction

Early social isolation (ESI) disrupts neurodevelopmental processes, potentially leading to long-lasting emotional and cognitive changes in adulthood. Communal nesting (CN), i.e., the sharing of parental responsibilities between multiple individuals in a nest, creates a socially enriching environment known to impact social and anxiety-related behaviors.

Methods

This study examines the effects of (i) the CN condition and of (ii) ESI during the 3rd week of life (i.e., pre-weaning ESI) on motor, cognitive, and emotional domains during adolescence and adulthood in male and female rats reared in the two different housing conditions, as well as (iii) the potential of CN to mitigate the impact of ESI on offspring.

Results

We found that in a spontaneous locomotor activity test, females exhibited higher activity levels compared to males. In female groups, adolescents reared in standard housing (SH) condition spent less time in the center of the arena, suggestive of increased anxiety levels, while the CN condition increased the time spent in the center during adolescence, but not adulthood, independently from ESI. The prepulse inhibition (PPI) test showed a reduced PPI in ESI adolescent animals of both sexes and in adult males (but not in adult females), with CN restoring PPI in males, but not in adolescent females. Further, in the marble burying test SH-ESI adolescent males exhibited higher marble burying behavior than all other groups, suggestive of obsessive-compulsive traits. CN completely reversed this stress-induced effect. Interestingly, ESI and CN did not have a significant impact on burying behavior in adult animals of both sexes.

Discussion

Overall, our findings (i) assess the effects of ESI on locomotion, sensorimotor gating, and compulsive-like behaviors, (ii) reveal distinct vulnerabilities of males and females within these domains, and (iii) show how early-life social enrichment may successfully counteract some of the behavioral alterations induced by early-life social stress in a sex-dependent manner. This study strengthens the notion that social experiences during early-life can shape emotional and cognitive outcomes in adulthood, and points to the importance of social enrichment interventions for mitigating the negative effects of early social stress on neurodevelopment.

Allostatic load in children: The cost of empathic concern

Early-life adversity affects long-term health outcomes but there is considerable interindividual variability in susceptibility to environmental influences. We proposed that positive psychological characteristics that reflect engagement with context, such as being concerned about people or performance on tasks (i.e., empathic concern), could moderate the interindividual variation in sensitivity to the quality of the early environment. We studied 526 children of various Asian nationalities in Singapore (46.6% female, 13.4% below the poverty line) with longitudinal data on perinatal and childhood experiences, maternal report on empathic concern of the child, and a comprehensive set of physiological measures reflecting pediatric allostatic load assessed at 6 y of age. The perinatal and childhood experiences included adversities and positive experiences. We found that cumulative adverse childhood experience was positively associated with allostatic load of children at 6 y of age at higher levels of empathic concern but not significantly associated at lower levels of empathic concern. This finding reveals evidence for the importance of empathic concern as a psychological characteristic that moderates the developmental impact of environmental influences, serving as a source for vulnerability to adversities in children.

The Effects of Early-Life Stress on Liver Transcriptomics and the Protective Role of EPA in a Mouse Model of Early-Life-Stress-Induced Adolescent Depression

Early-life stress (ELS) was found to increase the risk of adolescent depression, and clinical evidence indicated that eicosapentaenoic acid (EPA) was decreased in patients with adolescent depression, but the underlying mechanisms are unclear. Here, we utilized an ELS model of maternal separation with early weaning to explore the protective role of EPA in adolescent depression. We found that that ELS induced depression-like behavior rather than anxiety-like behavior in adolescent mice. RNA-sequencing results showed that ELS changed the transcription pattern in the liver, including 863 upregulated genes and 971 downregulated genes, especially those related to the biosynthesis of unsaturated fatty acids metabolism in the liver. Moreover, ELS decreased the expression of the rate-limiting enzymes, fatty acid desaturases 1/2 (FADS1/2), involved in the biosynthesis of EPA in the liver. Additionally, ELS reduced the levels of EPA in the liver, serum, and hippocampus, and EPA administration improved depression-like behavior-induced by ELS. Our results provide transcriptomic evidence that ELS increases the risk of adolescent depression by reducing the synthesis of unsaturated fatty acids in the liver, especially EPA, and suggest that supplementation with EPA should be investigated as a potential treatment for adolescent depression.

The Role of Oxytocin in Early-Life-Stress-Related Neuropsychiatric Disorders

Early-life stress during critical periods of brain development can have long-term effects on physical and mental health. Oxytocin is a critical social regulator and anti-inflammatory hormone that modulates stress-related functions and social behaviors and alleviates diseases. Oxytocin-related neural systems show high plasticity in early postpartum and adolescent periods. Early-life stress can influence the oxytocin system long term by altering the expression and signaling of oxytocin receptors. Deficits in social behavior, emotional control, and stress responses may result, thus increasing the risk of anxiety, depression, and other stress-related neuropsychiatric diseases. Oxytocin is regarded as an important target for the treatment of stress-related neuropsychiatric disorders. Here, we describe the history of oxytocin and its role in neural circuits and related behaviors. We then review abnormalities in the oxytocin system in early-life stress and the functions of oxytocin in treating stress-related neuropsychiatric disorders.

The impact of environmental factors during maternal separation on the behaviors of adolescent C57BL/6 mice

Neonatal maternal separation is a widely used method to construct an early-life stress model in rodents. In this method, pups are separated from their mothers for several hours every day during the first 2 weeks of life, which results in adverse early-life events. It is a known fact that maternal separation can exert a significant impact on the behavior and psychological health, such as anxiety and depression, in adolescent offspring. However, environmental conditions during maternal separation can differ such as the presence of other animals or by placing pups in a different dam. To investigate the differential effects of various conditions of maternal separation on the behavior of adolescent mice, we created the following groups: (1) iMS group: pups were moved to an isolated room with no other adult mice in a nearby cage, (2) eDam group: the pups randomly exchanged their dams, (3) OF group: pups were shifted to another cage with the bedding material containing maternal odor (olfactory stimulation), and (4) MS group: pups were shifted to another vivarium. From postnatal day (PND) 2-20 (i.e., 19 consecutive days), pups were separated from the dam daily for 4 h and exposed to various environments (MS, iMS, eDam, and OF) or were left undisturbed [control (CON) group]. A series of behavioral assessments were conducted to evaluate locomotion, anxiety, recognition, learning, and memory in adolescent offspring. The results showed that neonatal maternal separation led to impaired recognition memory, motor coordination, and motor skill learning across all groups. However, the iMS group exhibited anxiety-like behavior in the elevated plus maze test and enhanced the extinction of fear memory in the auditory fear conditioning test. The OF and eDam groups displayed partially recovered short-term working memory in the Y-maze test but exhibited opposite exploratory behaviors. The OF group spent more time in the center, while the eDam group spent less time. These findings demonstrated that exposure to different environmental conditions during maternal separation causes behavioral alterations in adolescent offspring, providing a potential explanation for the variation in behavioral phenotypes observed in the early-life stress models.

Early-Life Stress Impairs Perception and Neural Encoding of Rapid Signals in the Auditory Pathway

During developmental critical periods (CPs), early-life stress (ELS) induces cognitive deficits and alters neural circuitry in regions underlying learning, memory, and attention. Mechanisms underlying critical period plasticity are shared by sensory cortices and these higher neural regions, suggesting that sensory processing may also be vulnerable to ELS. In particular, the perception and auditory cortical (ACx) encoding of temporally-varying sounds both mature gradually, even into adolescence, providing an extended postnatal window of susceptibility. To examine the effects of ELS on temporal processing, we developed a model of ELS in the Mongolian gerbil, a well-established model for auditory processing. In both male and female animals, ELS induction impaired the behavioral detection of short gaps in sound, which are critical for speech perception. This was accompanied by reduced neural responses to gaps in auditory cortex, the auditory periphery, and auditory brainstem. ELS thus degrades the fidelity of sensory representations available to higher regions, and could contribute to well-known ELS-induced problems with cognition.SIGNIFICANCE STATEMENT In children and animal models, early-life stress (ELS) leads to deficits in cognition, including problems with learning, memory, and attention. Such problems could arise in part from a low-fidelity representation of sensory information available to higher-level neural regions. Here, we demonstrate that ELS degrades sensory responses to rapid variations in sound at multiple levels of the auditory pathway, and concurrently impairs perception of these rapidly-varying sounds. As these sound variations are intrinsic to speech, ELS may thus pose a challenge to communication and cognition through impaired sensory encoding.

Postnatal melatonin administration to stressed dams for ameliorating risk-taking behaviour in rat pups through maternal care improvement

BACKGROUND AND AIM

Anxiety often occurs both concurrently and sequentially in childhood and adolescence in association with prenatal stress, which may reduce the quality of maternal care and then cause mood disorders among children in later life. Against this background, melatonin, as a powerful antioxidant, was used in the present study to ameliorate risk-taking behaviour induced by pure maternal care in rat pups.

MATERIALS AND METHODS

The Wistar rat dams recruited in this study were exposed to restraint stress from gestational day (GD) 11 until delivery. They further received melatonin (10 mg/kg) during the postnatal days (PNDs) 0-7 by intraperitoneal (IP) injections at 4:00 PM. The pregnant rats were then divided into four groups, namely, control, stress, stress + melatonin and melatonin, and their maternal behaviour and corticosterone levels were measured. In the offspring, the outcomes of some behavioural tasks, including the elevated plus-maze (EPM) and open-field (OF) tests were ultimately assessed.

RESULTS

The study results revealed that the quantity and quality of maternal care significantly declined and the plasma corticosterone levels compounded in the stressed dams. Melatonin treatment, however, improved their nursing behaviour and reduced their plasma corticosterone levels. The offspring performance in two tasks also showed an upward trend in risk-taking behaviour in the stress group, and melatonin administration ameliorated the effects of stress and lessened their anxiety-like behaviour.

CONCLUSION

It was concluded that prenatal restraint stress could impair stress responses and quality of maternal care, whereas postnatal melatonin administration potentially contributed to the normalization of stress reaction and anxiolysis.

High-fat/high-sucrose diet worsens metabolic outcomes and widespread hypersensitivity following early-life stress exposure in female mice

Exposure to stress early in life has been associated with adult-onset comorbidities such as chronic pain, metabolic dysregulation, obesity, and inactivity. We have established an early-life stress model using neonatal maternal separation (NMS) in mice, which displays evidence of increased body weight and adiposity, widespread mechanical allodynia, and hypothalamic-pituitary-adrenal axis dysregulation in male mice. Early-life stress and consumption of a Western-style diet contribute to the development of obesity; however, relatively few preclinical studies have been performed in female rodents, which are known to be protected against diet-induced obesity and metabolic dysfunction. In this study, we gave naïve and NMS female mice access to a high-fat/high-sucrose (HFS) diet beginning at 4 wk of age. Robust increases in body weight and fat were observed in HFS-fed NMS mice during the first 10 wk on the diet, driven partly by increased food intake. Female NMS mice on an HFS diet showed widespread mechanical hypersensitivity compared with either naïve mice on an HFS diet or NMS mice on a control diet. HFS diet-fed NMS mice also had impaired glucose tolerance and fasting hyperinsulinemia. Strikingly, female NMS mice on an HFS diet showed evidence of hepatic steatosis with increased triglyceride levels and altered glucocorticoid receptor levels and phosphorylation state. They also exhibited increased energy expenditure as observed via indirect calorimetry and expression of proinflammatory markers in perigonadal adipose. Altogether, our data suggest that early-life stress exposure increased the susceptibility of female mice to develop diet-induced metabolic dysfunction and pain-like behaviors.

Insulin/IGF-dependent Wnt signaling promotes formation of germline tumors and other developmental abnormalities following early-life starvation in Caenorhabditis elegans

The Developmental Origins of Health and Disease hypothesis postulates that early-life stressors can predispose people to disease later in life. In the roundworm Caenorhabditis elegans, prolonged early-life starvation causes germline tumors, uterine masses, and other gonad abnormalities to develop in well-fed adults. Reduction of insulin/insulin-like growth factor (IGF) signaling (IIS) during larval development suppresses these starvation-induced abnormalities. However, molecular mechanisms at play in formation and suppression of starvation-induced abnormalities are unclear. Here we describe mechanisms through which early-life starvation and reduced IIS affect starvation-induced abnormalities. Transcriptome sequencing revealed that expression of genes in the Wnt signaling pathway is upregulated in adults starved as young larvae, and that knockdown of the insulin/IGF receptor daf-2/InsR decreases their expression. Reduction of Wnt signaling through RNAi or mutation reduced starvation-induced abnormalities, and hyperactivation of Wnt signaling produced gonad abnormalities in worms that had not been starved. Genetic and reporter-gene analyses suggest that Wnt signaling acts downstream of IIS in the soma to cell-nonautonomously promote germline hyperproliferation. In summary, this work reveals that IIS-dependent transcriptional regulation of Wnt signaling promotes starvation-induced gonad abnormalities, illuminating signaling mechanisms that contribute to adult pathology following early-life starvation.

Influence of early-life adversity on responses to acute and chronic ethanol in female mice

BACKGROUND

Stressful early-life experiences increase the risk of developing an alcohol use disorder. We previously found that male C57BL/6J mice reared under limited bedding and nesting (LBN) conditions, a model of early-life adversity, escalate their ethanol intake in limited-access two-bottle choice (2BC) sessions faster than control (CTL)-reared counterparts when exposed to chronic intermittent ethanol (CIE) vapor inhalation. However, the alcohol consumption of female littermates was not affected by LBN or CIE. In the present study, we sought to determine whether this phenotype reflected a general insensitivity of female mice to the influence of early-life stress on alcohol responses.

METHODS

In a first experiment, CTL and LBN females with a history of 2BC combined or not with CIE were tested in affective and nociceptive assays during withdrawal. In a second group of CTL and LBN females, we examined ethanol-induced antinociception, sedation, plasma clearance, and c-Fos induction.

RESULTS

In females withdrawn from chronic 2BC, CIE increased digging, reduced grooming, and increased immobility in the tail suspension test regardless of early-life history. In contrast, LBN rearing lowered mechanical nociceptive thresholds regardless of CIE exposure. In females acutely treated with ethanol, LBN rearing facilitated antinociception and delayed the onset of sedation without influencing ethanol clearance rate or c-Fos induction in the paraventricular nucleus of the hypothalamus, paraventricular nucleus of the thalamus, central nucleus of the amygdala, or auditory cortex.

CONCLUSION

CIE withdrawal produced multiple indices of negative affect in C57BL/6J females, suggesting that their motivation to consume alcohol may differ from air-exposed counterparts despite equivalent intake. Contrasted with our previous findings in males, LBN-induced mechanical hyperalgesia in chronic alcohol drinkers was specific to females. Lower nociceptive thresholds combined with increased sensitivity to the acute antinociceptive effect of ethanol may contribute to reinforcing ethanol consumption in LBN females but are not sufficient to increase their intake.

Associations between epigenetic aging and childhood peer victimization, depression, and suicidal ideation in adolescence and adulthood: A study of two population-based samples

Background: Prior studies indicate that peer victimization (including bullying) is associated with higher risk for depression and suicidal ideation across the life course. However, molecular mechanisms underlying these associations remain unclear. This two-cohort study proposes to test whether epigenetic aging and pace of aging, as well as a DNA methylation marker of responsive to glucocorticoids, are associated to childhood peer victimization and later depressive symptoms, or suicidal ideation. Methods: Cohort 1: Epigenome-wide DNA methylation (EPIC array) was measured in saliva collected when participants were 10.47 years (standard deviation = 0.35) in a subsample of the Quebec Longitudinal Study of Child Development (QLSCD, n = 149 participants), with self-reported peer victimization at 6-8 years, depressive symptoms (mean symptoms, and dichotomized top 30% symptoms) and suicidal ideation at 15-17 years. Cohort 2: Epigenome-wide DNA methylation (EPIC array) was measured in blood collected from participants aged 45.13 years (standard deviation = 0.37) in a subsample of the 1958 British Birth cohort (1958BBC, n = 238 participants) with information on mother-reported peer victimization at 7-11 years, self-reported depressive symptoms at 50 years, and suicidal ideation at 45 years. Five epigenetic indices were derived: three indicators of epigenetic aging [Horvath's pan-tissue (Horvath1), Horvath's Skin-and-Blood (Horvath2), Pediatric-Buccal-Epigenetic age (PedBE)], pace of aging (DunedinPACE), and stress response reactivity (Epistress). Results: Peer victimization was not associated with the epigenetic indices in either cohort. In the QLSCD, higher PedBE epigenetic aging and a slower pace of aging as measured by DunedinPACE predicted higher depressive symptoms scores. In contrast, neither the Horvath1, or Horvath2 epigenetic age estimates, nor the Epistress score were associated with depressive symptoms in either cohort, and none of the epigenetic indices predicted suicidal ideation. Conclusion: The findings are consistent with epigenome-wide and candidate gene studies suggesting that these epigenetic indices did not relate to peer victimization, challenging the hypothesis that cumulative epigenetic aging indices could translate vulnerability to depressive symptoms and suicidal ideation following peer victimization. Since some indices of epigenetic aging and pace of aging signaled higher risk for depressive symptoms, future studies should pursue this investigation to further evaluate the robustness and generalization of these preliminary findings.

Asinine milk mitigates stress-mediated immune, cortisol and behavioral responses of piglets to weaning: A study to foster future interventions in humans

Introduction

The present study assessed whether asinine milk supplementation improved the immune and behavioral responses of piglets during an early life weaning stress event as a model for its future use in humans.

Methods

For this, 48 piglets from 4 different litters were used. At 20 days of age, piglets were weighed and allocated with their litter and dam into group pens until 28 days of age. Four piglets from each litter were then randomly assigned to either (1) asinine milk supplementation (n = 16) (2), skimmed cow milk supplementation (n = 16) or (3) no supplementation (n = 16; control group). The supplementations were voluntarily administered for 3 days preweaning and 3 days postweaning using a baby bottle. The effects on the weaning stress response were assessed through salivary cortisol measurements; behavioral tests such as the open field, novel object end elevated plus maze tests; and gene expression of HSD11B1, NR3C1 and IL1B in PBMCs, which was determined by RT-qPCR and normalized to GAPDH and UBB. To test the effect of the supplementations on weight, milk intake, gene expression, and behavior, a randomized block design was used with repeated measurements over time by the PROC MIXED procedure.

Results and discussion

The effects on salivary cortisol were determined using the ratio between the morning and afternoon concentrations, considering the time before and after the weaning event. Principal component analysis (PCA) and Fisher's test were performed to evaluate the behavior test data. When comparing salivary cortisol concentrations between the pre- and postweaning periods, there was a difference (p < 0.05) between the supplementation groups in the afternoon period, suggesting that piglets fed asinine milk had lower afternoon cortisol concentrations postweaning than their counterparts. For the behavioral tests, the supplementations had no measurable effects. No difference was between groups pre- and postweaning for the expression of HSD11B2, which codes for an enzyme that breaks down cortisol. However, the expression of NR3C1, which encodes the glucocorticoid receptor, was significantly upregulated in piglets supplemented with cow milk (mean 1.245; p < 0.05).

Conclusion

Asinine milk downregulated 1L1B gene expression, which codes for an inflammatory cytokine. In conclusion, these results suggest that supplementation with asinine milk may represent a strategy to diminish the damage associated with an early life event by modulating IL1B expression and reducing salivary cortisol levels in piglets undergoing weaning stress. Further transcriptomic and metabolomic studies may improve our understanding of the molecular pathways that mediate this systemic immune-mediated response.

Limited bedding nesting paradigm alters maternal behavior and pup's early developmental milestones but did not induce anxiety- or depressive-like behavior in two different inbred mice

Animal models are crucial to understanding the mechanisms underlying the deleterious consequences of early-life stress. Here, we aimed to examine the effect of the limited bedding nesting (LBN) paradigm on early life development milestones and anxiety- and/or depression-like behavior in adolescent and adult mice from two inbred mice of both sexes. C57BL/6NCrl and BALB/c litters were exposed to the LBN paradigm postnatal day (PND) 2-9. Maternal behavior recording occurred on PND 3-9, and pups were weighed daily and examined to verify the eye-opening on PND 10-22. The male and female offspring underwent evaluation in the open field test, elevated plus-maze, and the forced swimming test during adolescence (PND 45-49) and adulthood (PND 75-79). We found that LBN impaired the maternal behavior patterns of both strain dams, mainly on C57BL/6NCrl strain. Also, LBN delayed the pup's eye-opening time and reduced body weight gain, impacting C57BL/6NCrl pups more. We also found that LBN decreased anxiety-related indices in adolescent and adult male but not female mice of both strains. Furthermore, LBN decreased depression-related indices only adolescent female and male BALB/c and female but not male C57BL/6NCrl mice. These findings reinforce the evidence that the LBN paradigm impairs the maternal behavior pattern and pup's early developmental milestones but does not induce anxiety- or depressive-like behavior outcomes during later life.

Early-life stress and current stress predict BMI and height growth trajectories in puberty

In cross-sectional analyses, early institutional care is associated with shorter stature but not obesity during puberty in children adopted into US families. We examined whether shorter stature and leaner body composition in youth adopted internationally from institutions would continue as puberty progressed. We also examined whether current psychosocial stress would moderate the association between early institutional deprivation and growth during adolescence. Using an accelerated longitudinal design and linear mixed-effects models, we examined the height and body mass index (BMI) of 132 previously institutionalized (PI) and 176 nonadopted (NA) youth. We examined youth aged 7-15 at the beginning of the study three times across 2 years. Nurses assessed anthropometrics and pubertal status. Current psychosocial stress was measured using the Youth Life Stress Interview. Our results indicated that PI youth remained shorter and leaner across three assessments than NA youth. However, age-and-sex-adjusted BMI increased faster in PI youth. Psychosocial stress during puberty predicted greater age-and-sex-adjusted BMI, but this effect did not differ by group. The gap in BMI but not height appears to close between PI and NA youth. Higher psychosocial stress was associated with higher BMI during puberty.

Early-life stress and dietary fatty acids impact the brain lipid/oxylipin profile into adulthood, basally and in response to LPS

Brain lipid dysregulation is a hallmark of depression and Alzheimer's disease, also marked by chronic inflammation. Early-life stress (ELS) and dietary intake of polyunsaturated fatty acids (PUFAs) are risk factors for these pathologies and are known to impact inflammatory processes. However, if these early-life factors alter brain lipid homeostasis on the long-term and thereby contribute to this risk remains to be elucidated. We have recently shown that an early diet enriched in omega(ω)-3 PUFAs protected against the long-term negative effects of ELS on cognition and neuroinflammation. Here, we aim to understand if modulation of brain lipid and oxylipin profiles contributes to the detrimental effects of ELS and the protective ones of the diet. We therefore studied if and how ELS and early dietary PUFAs modulate the brain lipid and oxylipin profile, basally as well as in response to an inflammatory challenge, to unmask possible latent effects. Male mice were exposed to ELS via the limited bedding and nesting paradigm, received an early diet with high or low ω6/ω3 ratio (HRD and LRD) and were injected with saline or lipopolysaccharide (LPS) in adulthood. Twenty-four hours later plasma cytokines (Multiplex) and hypothalamic lipids and oxylipins (liquid chromatography tandem mass spectrometry) were measured. ELS exacerbated the LPS-induced increase in IL-6, CXCL1 and CCL2. Both ELS and diet affected the lipid/oxylipin profile long-term. For example, ELS increased diacylglycerol and LRD reduced triacylglycerol, free fatty acids and ceramides. Importantly, the ELS-induced alterations were strongly influenced by the early diet. For example, the ELS-induced decrease in eicosapentaenoic acid was reversed when fed LRD. Similarly, the majority of the LPS-induced alterations were distinct for control and ELS exposed mice and unique for mice fed with LRD or HRD. LPS decreased ceramides and lysophosphotidylcholine, increased hexosylceramides and prostaglandin E₂, reduced triacylglycerol species and ω6-derived oxylipins only in mice fed LRD and ELS reduced the LPS-induced increase in phosphatidylcholine. These data give further insights into the alterations in brain lipids and oxylipins that might contribute to the detrimental effects of ELS, to the protective ones of LRD and the possible early-origin of brain lipid dyshomeostasis characterizing ELS-related psychopathologies.

Developmental effects of early-life stress on dopamine D2 receptor and proteins involved in noncanonical D2 dopamine receptor signaling pathway in the prefrontal cortex of male rats

OBJECTIVES

Dopamine neurotransmission is implicated in multiple neuropsychiatric disorders, most strikingly in Parkinson's disease, bipolar disorder, attention-deficit hyperactivity disorder and schizophrenia. In addition to canonical pathway, D2-receptor (D2R) exerts some of its biological actions through regulating the activity of Akt and GSK3, which in turn were found to be altered in several psychiatric illnesses. The present study examined the impacts of maternal separation, an early-life stress model which has been associated with disturbed neurodevelopment and appearance of many psychiatric disorders, on developmental changes in dopamine concentration and the expression of D2Rs, Akt and GSK-3β in the medial prefrontal cortex (PFC; a key target of stress) in adolescent and young adult male rats.

METHODS

Maternal separation was performed 3 h per day from postnatal days 2 to 11. The PFC protein and dopamine contents were determined using western blotting analysis and Eliza, respectively.

RESULTS

Results indicated long-term increases in the prefrontal dopamine levels in stressed adolescent and young adult male rats, accompanied by significant downregulation of D2R as well as upregulation of p-Akt and GSK-3β contents in stressed adolescence compared to controls, with all protein levels that returned to control values in stressed adult rats.

CONCLUSIONS

Our findings suggest that early-life stress differentially modulates prefrontal D2R/Akt/GSK-3β levels during development. Since adolescence period is susceptible to the onset of specific mental illnesses, disruption of noncanonical components of D2R signaling during this critical period may have an important role in programming neurobehavioral phenotypes in adulthood and manipulations influencing Akt/GSK-3β pathway may improve the expression of specific dopamine-related behaviors and the effects of dopaminergic drugs.

The effect of cumulative early life adversities, and their differential mediation through hair cortisol levels, on childhood growth and cognition: Three-year follow-up of a birth cohort in rural India

Background: Early adversities negatively impact children's growth and development, putatively mediated by chronic physiological stress resulting from these adverse experiences. We aimed to estimate the associations between prospectively measured cumulative early adversities with growth and cognition outcomes in rural Indian preschool children and to explore if hair cortisol concentration (HCC), a measure of chronic physiological stress, mediated the above association. Methods: Participants were recruited from the SPRING cRCT in rural Haryana, India. Adversities experienced through pregnancy and the first year of life were measured in 1304 children at 12-months. HCC was measured at 12-months in 845 of them. Outcome measures were height-for-age-z-score (HAZ), weight-for-age-z-score (WAZ) and cognition, measured in 1124 children followed up at 3-years. Cognition was measured using a validated tablet-based gamified tool named DEEP. Results: Cumulative adversities at 12-months were inversely associated with all outcomes measures at 3-years. Each unit increase in adversity score led to a decrease of 0·08 units [95% confidence interval (CI):-0·11,-0·06] in DEEP-z-score; 0·12 units [-0·14,-0·09] in HAZ and 0·11 units [-0·13,-0·09] in WAZ. 12-month HCC was inversely associated with DEEP-z-score (-0·09 [-0·16,-0·01]) and HAZ (-0·12 [-0·20,-0·04]), but the association with WAZ was not significant (p = 0·142). HCC marginally mediated the association between cumulative adversities and HAZ (proportion mediated = 0·06, p = 0·014). No evidence of mediation was found for the cognition outcome. Conclusions: Cumulative early adversities and HCC measured at 12-months have persistent negative effects on child growth and cognition at 3-years. The association between adversities and these two child outcomes were differentially mediated by HCC, with no evidence of mediation observed for the cognitive outcome. Future studies should focus on other stress biomarkers, and alternate pathways such as the immune, inflammation and cellular ageing pathways, to unpack key mechanisms underlying the established relationship between early adversities and poor child outcomes.

Associations between early-life stress exposure and internalizing symptomatology during the COVID-19 pandemic: Assessing the role of neurobehavioral mediators

Background

The ongoing COVID-19 pandemic is a major stressor that has been associated with increased risk for psychiatric illness in the general population. Recent work has highlighted that experiences of early-life stress (ELS) may impact individuals' psychological functioning and vulnerability for developing internalizing psychopathology in response to pandemic-related stress. However, little is known about the neurobehavioral factors that may mediate the association between ELS exposure and COVID-related internalizing symptomatology. The current study sought to examine the mediating roles of pre-pandemic resting-state frontoamygdala connectivity and concurrent emotion regulation (ER) in the association between ELS and pandemic-related internalizing symptomatology.

Methods

Retrospective life-stress histories, concurrent self-reported ER strategies (i.e., reappraisal and suppression), concurrent self-reported internalizing symptomatology (i.e., depression- and anxiety-related symptomatology), and resting-state functional connectivity data from a sample of adults (N = 64, M age = 22.12, female = 68.75%) were utilized.

Results

There were no significant direct associations between ELS and COVID-related internalizing symptomatology. Neither frontoamygdala functional connectivity nor ER strategy use mediated an association between ELS and COVID-related internalizing symptomatology (ps > 0.05). Exploratory analyses identified a significant moderating effect of reappraisal use on the association between ELS and internalizing symptomatology (β = -0.818, p = 0.047), such that increased reappraisal use buffered the impact of ELS on psychopathology.

Conclusions

While frontoamygdala connectivity and ER do not appear to mediate the association between ELS and COVID-related internalizing symptomatology, our findings suggest that the use of reappraisal may buffer against the effect of ELS on mental health during the pandemic.

The Role of the Gut Microbiota in the Effects of Early-Life Stress and Dietary Fatty Acids on Later-Life Central and Metabolic Outcomes in Mice

Early-life stress (ELS) leads to increased vulnerability for mental and metabolic disorders. We have previously shown that a low dietary ω-6/ω-3 polyunsaturated fatty acid (PUFA) ratio protects against ELS-induced cognitive impairments. Due to the importance of the gut microbiota as a determinant of long-term health, we here study the impact of ELS and dietary PUFAs on the gut microbiota and how this relates to the previously described cognitive, metabolic, and fatty acid profiles. Male mice were exposed to ELS via the limited bedding and nesting paradigm (postnatal day (P)2 to P9 and to an early diet (P2 to P42) with an either high (15) or low (1) ω-6 linoleic acid to ω-3 alpha-linolenic acid ratio. 16S rRNA was sequenced and analyzed from fecal samples at P21, P42, and P180. Age impacted α- and β-diversity. ELS and diet together predicted variance in microbiota composition and affected the relative abundance of bacterial groups at several taxonomic levels in the short and long term. For example, age increased the abundance of the phyla Bacteroidetes, while it decreased Actinobacteria and Verrucomicrobia; ELS reduced the genera RC9 gut group and Rikenella, and the low ω-6/ω-3 diet reduced the abundance of the Firmicutes Erysipelotrichia. At P42, species abundance correlated with body fat mass and circulating leptin (e.g., Bacteroidetes and Proteobacteria taxa) and fatty acid profiles (e.g., Firmicutes taxa). This study gives novel insights into the impact of age, ELS, and dietary PUFAs on microbiota composition, providing potential targets for noninvasive (nutritional) modulation of ELS-induced deficits. IMPORTANCE Early-life stress (ELS) leads to increased vulnerability to develop mental and metabolic disorders; however, the biological mechanisms leading to such programming are not fully clear. Increased attention has been given to the importance of the gut microbiota as a determinant of long-term health and as a potential target for noninvasive nutritional strategies to protect against the negative impact of ELS. Here, we give novel insights into the complex interaction between ELS, early dietary ω-3 availability, and the gut microbiota across ages and provide new potential targets for (nutritional) modulation of the long-term effects of the early-life environment via the microbiota.

The early-life stress induced by oxytocin inhibition in p53 knockout mouse dams increases adulthood tumorigenesis in first and second generations

BACKGROUND

Early-life stress due to poor parental care has been suggested to increase cancer risk, though, so far, no experimental evidence established a link between defective parental behavior and spontaneous tumorigenesis in progeny. Essential maternal behavior is regulated, in particular, by the oxytocin (OT) hormonal circuit, which in turn responds to stimuli from the offspring and impinges on the central nervous systems.

METHODS

By providing L-368,899 OT receptor (OTR) inhibitor to lactating mothers, we set up a model of defective maternal care in p53 knockout mice.

RESULTS

The progeny of these dams showed, later in life, higher cortisol levels, shortened life span and increased tumorigenic potential of bone marrow cells (BMC). Notably, these phenotypes were transmitted to the following generation.

CONCLUSIONS

Therefore, the inhibition of OT function in mothers is a novel paradigm of early-life stress that is inherited across generations and increases cancer risk in tumor-prone mice.

Effects of short environmental enrichment on early-life adversity induced cognitive alternations in adolescent rats

Early-life experiences, including parental care, affect cognitive performance later in life. Being exposed to early-life maternal separation (MS) increases susceptibility to stress-related psychopathology. Previous studies suggest that MS could induce learning and memory impairments. Since enriched environment (EE) provides more opportunities for exploration and social interaction, in the present study we evaluated the effects of a short EE paradigm with a duration of 13 days on cognitive abilities of maternally separated rats (MS; 180 min/day, postnatal day (PND) 1-21) during adolescence in four experimental groups: Control, Control+EE, MS, and MS+EE. Plasma corticosterone (CORT) and brain-derived neurotrophic factor (BDNF) levels were also measured in experimental animals. We also studied the induction of long-term potentiation (LTP) in the slices of hippocampal CA1 area. The behavioral and electrophysiological assessments were started at PND 35. MS caused higher basal CORT levels in plasma and impaired spatial learning, memory, and social interaction. LTP induction was also impaired in MS rats and plasma BDNF levels were reduced in these animals. MS also induced more anxiety-like behavior. Short EE reduced plasma CORT levels had the potential to improve locomotor activity and anxiety-like behavior in MS+EE rats and reversed MS-induced impairments of spatial learning, memory, and social behavior. LTP induction and plasma BDNF levels were also enhanced in MS+EE rats. We concluded that short EE might be considered as a therapeutic strategy for promoting cognition.

The effects of neonatal procedural pain and maternal isolation on hippocampal cell proliferation and reelin concentration in neonatal and adult male and female rats

Preterm births accounted for over 10% of all U.S. live births in 2019 and the rate is rising. Neonatal stressors, especially procedural pain, experienced by preterm infants in the neonatal intensive care unit (NICU) have been associated with neurodevelopmental impairments. Parental care can alleviate stress during stressful or painful procedures; however, infants in the NICU often receive reduced parental care compared with their peers. Animal studies suggest that decreased maternal care similarly impairs neurodevelopment but also influences the effects of neonatal pain. It is important to mimic both stressors in animal models of neonatal stress exposure. In this study, researchers investigated the individual and combined impact of neonatal pain and maternal isolation on reelin protein levels and cellular proliferation in the hippocampal dentate gyrus of 8 days old and adult rats. Exposure to either stressor individually, but not both, increased reelin levels in the dentate gyrus of adult females without significantly altering reelin levels in adult males. However, cell proliferation levels at either age were unaffected by the early-life stressors. These results suggest that each early-life stressor has a unique effect on markers of brain development and more research is needed to further investigate their distinct influences.

Mild early-life stress exaggerates the impact of acute stress on corticolimbic resting-state functional connectivity

Abundant evidence shows that early‐life stress (ELS) predisposes for the development of stress‐related psychopathology when exposed to stressors later in life, but the underlying mechanisms remain unclear. To study predisposing effects of mild ELS on stress sensitivity, we examined in a healthy human population the impact of a history of ELS on acute stress‐related changes in corticolimbic circuits involved in emotional processing (i.e., amygdala, hippocampus and ventromedial prefrontal cortex [vmPFC]). Healthy young male participants (n = 120) underwent resting‐state functional magnetic resonance imaging (fMRI) in two separate sessions (stress induction vs. control). The Childhood Trauma Questionnaire (CTQ) was administered to index self‐reported ELS, and stress induction was verified using salivary cortisol, blood pressure, heart rate and subjective affect. Our findings show that self‐reported ELS was negatively associated with baseline cortisol, but not with the acute stress‐induced cortisol response. Critically, individuals with more self‐reported ELS exhibited an exaggerated reduction of functional connectivity in corticolimbic circuits under acute stress. A mediation analysis showed that the association between ELS and stress‐induced changes in amygdala–hippocampal connectivity became stronger when controlling for basal cortisol. Our findings show, in a healthy sample, that the effects of mild ELS on functioning of corticolimbic circuits only become apparent when exposed to an acute stressor and may be buffered by adaptations in hypothalamic–pituitary–adrenal axis function. Overall, our findings might reveal a potential mechanism whereby even mild ELS might confer vulnerability to exposure to stressors later in adulthood.

The Value of Dimensional Models of Early Experience: Thinking Clearly About Concepts and Categories

We review the three prevailing approaches-specificity, cumulative risk, and dimensional models-to conceptualizing the developmental consequences of early-life adversity and address fundamental problems with the characterization of these frameworks in a recent Perspectives on Psychological Science piece by Smith and Pollak. We respond to concerns raised by Smith and Pollak about dimensional models of early experience and highlight the value of these models for studying the developmental consequences of early-life adversity. Basic dimensions of adversity proposed in existing models include threat/harshness, deprivation, and unpredictability. These models identify core dimensions of early experience that cut across the categorical exposures that have been the focus of specificity and cumulative risk approaches (e.g., abuse, institutional rearing, chronic poverty); delineate aspects of early experience that are likely to influence brain and behavioral development; afford hypotheses about adaptive and maladaptive responses to different dimensions of adversity; and articulate specific mechanisms through which these dimensions exert their influences, conceptualizing experience-driven plasticity within an evolutionary-developmental framework. In doing so, dimensional models advance specific falsifiable hypotheses, grounded in neurodevelopmental and evolutionary principles, that are supported by accumulating evidence and provide fertile ground for empirical studies on early-life adversity.

The Value of Dimensional Models of Early Experience: Thinking Clearly About Concepts and Categories

We review the three prevailing approaches-specificity, cumulative risk, and dimensional models-to conceptualizing the developmental consequences of early-life adversity and address fundamental problems with the characterization of these frameworks in a recent Perspectives on Psychological Science piece by Smith and Pollak. We respond to concerns raised by Smith and Pollak about dimensional models of early experience and highlight the value of these models for studying the developmental consequences of early-life adversity. Basic dimensions of adversity proposed in existing models include threat/harshness, deprivation, and unpredictability. These models identify core dimensions of early experience that cut across the categorical exposures that have been the focus of specificity and cumulative risk approaches (e.g., abuse, institutional rearing, chronic poverty); delineate aspects of early experience that are likely to influence brain and behavioral development; afford hypotheses about adaptive and maladaptive responses to different dimensions of adversity; and articulate specific mechanisms through which these dimensions exert their influences, conceptualizing experience-driven plasticity within an evolutionary-developmental framework. In doing so, dimensional models advance specific falsifiable hypotheses, grounded in neurodevelopmental and evolutionary principles, that are supported by accumulating evidence and provide fertile ground for empirical studies on early-life adversity.

Migration-related trauma and mental health among migrant children emigrating from Mexico and Central America to the United States: Effects on developmental neurobiology and implications for policy

Children make up over half of the world's migrants and refugees and face a multitude of traumatic experiences prior to, during, and following migration. Here, we focus on migrant children emigrating from Mexico and Central America to the United States and review trauma related to migration, as well as its implications for the mental health of migrant and refugee children. We then draw upon the early adversity literature to highlight potential behavioral and neurobiological sequalae of migration-related trauma exposure, focusing on attachment, emotion regulation, and fear learning and extinction as transdiagnostic mechanisms underlying the development of internalizing and externalizing symptomatology following early-life adversity. This review underscores the need for interdisciplinary efforts to both mitigate the effects of trauma faced by migrant and refugee youth emigrating from Mexico and Central America and, of primary importance, to prevent child exposure to trauma in the context of migration. Thus, we conclude by outlining policy recommendations aimed at improving the mental health of migrant and refugee youth.

Exposure to Vicarious Social Defeat Stress and Western-Style Diets During Adolescence Leads to Physiological Dysregulation, Decreases in Reward Sensitivity, and Reduced Antidepressant Efficacy in Adulthood

A dramatic increase in the prevalence of major depression and diet-related disorders in adolescents has been observed over several decades, yet the mechanisms underlying this comorbidity have only recently begun to be elucidated. Exposure to western-style diet (WSD), high in both fats (45% kcal) and carbohydrates (35% kcal): e.g., high fat diet (HFD), has been linked to the development of metabolic syndrome-like symptoms and behavioral dysregulation in rodents, as similarly observed in the human condition. Because adolescence is a developmental period highlighted by vulnerability to both stress and poor diet, understanding the mechanism(s) underlying the combined negative effects of WSDs and stress on mood and reward regulation is critical. To this end, adolescent male C57 mice were exposed to vicarious social defeat stress (VSDS), a stress paradigm capable of separating physical (PS) versus psychological/emotional (ES) stress, followed by normal chow (NC), HFD, or a separate control diet high in carbohydrates (same sucrose content as HFD) and low in fat (LFD), while measuring body weight and food intake. Non-stressed control mice exposed to 5 weeks of NC or HFD showed no significant differences in body weight or social interaction. Mice exposed to VSDS (both ES and PS) gain weight rapidly 1 week after initiation of HFD, with the ES-exposed mice showing significantly higher weight gain as compared to the HFD-exposed control mice. These mice also exhibited a reduction in saccharin preference, indicative of anhedonic-like behavior. To further delineate whether high fat was the major contributing factor to these deficits, LFD was introduced. The mice in the VSDS + HFD gained weight more rapidly than the VSDS + LFD group, and though the LFD-exposed mice did not gain weight as rapidly as the HFD-exposed mice, both the VSDS + LFD- and VSDS + HFD-exposed mice exhibited attenuated response to the antidepressant fluoxetine. These data show that diets high in both fats and carbohydrates are responsible for rapid weight gain and reduced reward sensitivity; and that while consumption of diet high in carbohydrate and low in fat does not lead to rapid weight gain, both HFD and LFD exposure after stress leads to reduced responsiveness to antidepressant treatment.

Effects of early-life stress and sex on blood-brain barrier permeability and integrity in juvenile and adult rats

Early-life stress (ELS) is considered a relevant etiological factor for neurodegenerative and mental disorders. In the present study, we hypothesized that ELS may persistently and sex dependently influence blood-brain barrier (BBB) integrity and function during critical periods of brain development and consequently determine susceptibility to and sex-related prevalence of chronic diseases in adult life. We used the maternal separation (MS) procedure in rats to model ELS and evaluated BBB permeability and gene expression of selected tight junction (TJ) proteins, glucose transporter type 1 (Slc2a1) and aquaporin 4 (Aqp4) in the medial prefrontal cortex (mPFC), dorsal striatum (dSTR) and hippocampus of juvenile and adult rats. Serum concentrations of a peripheral marker of BBB function (S100β) and proinflammatory cytokines were also assessed. We observed developmental sealing of the BBB and sex differences in the permeability of the BBB and the mRNA expression of TJ proteins and Slc2a1. Adult females showed lower BBB permeability and higher levels of Cldn3, Cldn5, Ocln, and Slc2a1 in the mPFC and dSTR than males. MS temporarily increased BBB permeability in the dSTR of juvenile males and affected mRNA expression of the majority of studied proteins related to BBB function in age-, region- and sex-dependent manners. Additionally, MS sex dependently decreased serum S100β levels and did not affect proinflammatory cytokine concentrations. In general, our study did not reveal a clear or strong negative effect of MS on BBB integrity. However, the results suggest that ELS may induce adaptive/maladaptive changes or compensatory mechanisms within the BBB of unknown yet consequences.

Modulation of the Hypothalamic Nutrient Sensing Pathways by Sex and Early-Life Stress

There are sex differences in metabolic disease risk, and early-life stress (ES) increases the risk to develop such diseases, potentially in a sex-specific manner. It remains to be understood, however, how sex and ES affect such metabolic vulnerability. The hypothalamus regulates food intake and energy expenditure by sensing the organism's energy state via metabolic hormones (leptin, insulin, ghrelin) and nutrients (glucose, fatty acids). Here, we investigated if and how sex and ES alter hypothalamic nutrient sensing short and long-term. ES was induced in mice by limiting the bedding and nesting material from postnatal day (P)2-P9, and the expression of genes critical for hypothalamic nutrient sensing were studied in male and female offspring, both at P9 and in adulthood (P180). At P9, we observed a sex difference in both Ppargc1a and Lepr expression, while the latter was also increased in ES-exposed animals relative to controls. In adulthood, we found sex differences in Acacb, Agrp, and Npy expression, whereas ES did not affect the expression of genes involved in hypothalamic nutrient sensing. Thus, we observe a pervasive sex difference in nutrient sensing pathways and a targeted modulation of this pathway by ES early in life. Future research is needed to address if the modulation of these pathways by sex and ES is involved in the differential vulnerability to metabolic diseases.

A Search for Biomarkers of Early-life Stress-related Psychopathology: Focus on 70-kDa Heat Shock Proteins

Clinical studies clearly indicate that early-life stress (ELS) may cause physical and mental health problems later in life. Therefore, the identification of universal biomarkers of ELS-related diseases is very important. The 70-kDa heat shock proteins (HSP70s), specifically HSPA5 and HSPA1B, have been recently shown to be potentially associated with occurrence of anxiety, mood disorders, and schizophrenia; thus, we hypothesized that HSP70s are potential candidate biomarkers of ELS-induced psychopathologies. A maternal separation (MS) procedure in rats was used to model ELS, and the expression of HSPA5 and HSPA1B was investigated in the blood, medial prefrontal cortex (mPFC), and hippocampus of juvenile, preadolescent, and adult animals. We also studied the effects of MS on the long-term potentiation (LTP) and behavioral phenotypes of adult rats. We found that MS enhanced the expression of HSPA1B mRNA in the blood and mPFC of juvenile and preadolescent rats. This increase was accompanied by an increase in the HSPA1A/1B protein levels in the mPFC and hippocampus of juvenile rats that persisted in the mPFC until adulthood. MS juvenile and adult rats showed enhanced HSPA5 mRNA expression in the blood and increased HSPA5 protein expression in the mPFC (juveniles) and hippocampus (adults). Concurrently, MS adult rats exhibited aberrations in LTP in the mPFC and hippocampus and a less anxious behavioral phenotype. These results indicate that MS may produce enduring overexpression of HSPA1B and HSPA5 in the brain and blood. Therefore, both HSP70 family members may be potential candidate peripheral and brain biomarkers of ELS-induced changes in brain functioning.

Early-life stress induces genome-wide sex-dependent miRNA expression and correlation across limbic brain areas in rats

Aims:

The aim of this study was to assess regional- and sex-dependent changes in miRNA expression resulting from early-life stress (ELS).

Materials and methods:

Small RNA sequencing was used to determine sex-dependent changes in miRNAs after maternal separation, a rodent model of ELS, across the prefrontal cortex, amygdala and hippocampus.

Results:

Maternal separation induced anhedonia and altered miRNA expression in a sex-dependent manner, particularly in the prefrontal cortex and hippocampus. Gene ontology revealed that these miRNAs target genes with brain-specific biological functions.

Conclusion:

Using a network approach to explore miRNA signaling across the brain after ELS, regional differences were highlighted as key to studying the brain’s stress response, which indicates that sex is critical for understanding miRNA-mediated ELS-induced behavior.

Dysregulation of the mesoprefrontal dopamine circuit mediates an early-life stress-induced synaptic imbalance in the prefrontal cortex

Stress adversely affects an array of cognitive functions. Although stress-related disorders are often addressed in adulthood, far less is known about how early-life stress (ELS) affects the developing brain in early postnatal periods. Here we show that ELS, induced by maternal separation, leads to synaptic alteration of layer 2/3 pyramidal neurons in the prefrontal cortex (PFC) of mice. We find that layer 2/3 neurons show increased excitatory synapse numbers following ELS and that this is accompanied by hyperexcitability of PFC-projecting dopamine (DA) neurons in the ventral tegmental area. Notably, excitatory synaptic change requires local signaling through DA D2 receptors. In vivo pharmacological treatment with a D2 receptor agonist in the PFC of control mice mimics the effects of ELS on synaptic alterations. Our findings reveal a neuromodulatory mechanism underlying ELS-induced PFC dysfunction, and this mechanism may facilitate a more comprehensive understanding of how ELS leads to mental disorders.

Opposing relationships of childhood threat and deprivation with stria terminalis white matter

While stress may be a potential mechanism by which childhood threat and deprivation influence mental health, few studies have considered specific stress‐related white matter pathways, such as the stria terminalis (ST) and medial forebrain bundle (MFB). Our goal was to examine the relationships between childhood adversity and ST and MFB structural integrity and whether these pathways may provide a link between childhood adversity and affective symptoms and disorders. Participants were young adults (n = 100) with a full distribution of maltreatment history and affective symptom severity. Threat was determined by measures of childhood abuse and repeated traumatic events. Socioeconomic deprivation (SED) was determined by a measure of childhood socioeconomic status (parental education). Participants underwent diffusion spectrum imaging. Human Connectome Project data was used to perform ST and MFB tractography; these tracts were used as ROIs to extract generalized fractional anisotropy (gFA) from each participant. Childhood threat was associated with ST gFA, such that greater threat was associated with less ST gFA. SED was also associated with ST gFA, however, conversely to threat, greater SED was associated with greater ST gFA. Additionally, threat was negatively associated with MFB gFA, and MFB gFA was negatively associated with post‐traumatic stress symptoms. Our results suggest that childhood threat and deprivation have opposing influences on ST structural integrity, providing new evidence that the context of childhood adversity may have an important influence on its neurobiological effects, even on the same structure. Further, the MFB may provide a novel link between childhood threat and affective symptoms.

Social Defeat Stress During Early Adolescence Confers Resilience Against a Single Episode of Prolonged Stress in Adult Rats

Early-life adverse experiences (first hit) lead to coping strategies that may confer resilience or vulnerability to later experienced stressful events (second hit) and the subsequent development of stress-related psychopathologies. Here, we investigated whether exposure to two stressors at different stages in life has long-term effects on emotional and cognitive capabilities, and whether the interaction between the two stressors influences stress resilience. Male rats were subjected to social defeat stress (SDS, first hit) in adolescence and to a single episode of prolonged stress (SPS, second hit) in adulthood. Behavioral outcomes, hippocampal expression of brain-derived neurotrophic factor, and plasma corticosterone levels were tested in adulthood. Rats exposed to both stressors exhibited resilience against the development of stress-induced alterations in emotional behaviors and spatial memory, but vulnerability to cued fear memory dysfunction. Rats subjected to both stressors demonstrated resilience against the SDS-induced alterations in hippocampal brain-derived neurotrophic factor expression and plasma corticosterone levels. SPS alone altered locomotion and spatial memory retention; these effects were absent in SDS-exposed rats later exposed to SPS. Our findings reveal that exposure to social stress during early adolescence influences the ability to cope with a second challenge experienced later in life.

Effects of Early-Life Stress, Postnatal Diet Modulation and Long-Term Western-Style Diet on Peripheral and Central Inflammatory Markers

Early-life stress (ES) exposure increases the risk of developing obesity. Breastfeeding can markedly decrease this risk, and it is thought that the physical properties of the lipid droplets in human milk contribute to this benefit. A concept infant milk formula (IMF) has been developed that mimics these physical properties of human milk (Nuturis®, N-IMF). Previously, we have shown that N-IMF reduces, while ES increases, western-style diet (WSD)-induced fat accumulation in mice. Peripheral and central inflammation are considered to be important for obesity development. We therefore set out to test the effects of ES, Nuturis® and WSD on adipose tissue inflammatory gene expression and microglia in the arcuate nucleus of the hypothalamus. ES was induced in mice by limiting the nesting and bedding material from postnatal day (P) 2 to P9. Mice were fed a standard IMF (S-IMF) or N-IMF from P16 to P42, followed by a standard diet (STD) or WSD until P230. ES modulated adipose tissue inflammatory gene expression early in life, while N-IMF had lasting effects into adulthood. Centrally, ES led to a higher microglia density and more amoeboid microglia at P9. In adulthood, WSD increased the number of amoeboid microglia, and while ES exposure increased microglia coverage, Nuturis® reduced the numbers of amoeboid microglia upon the WSD challenge. These results highlight the impact of the early environment on central and peripheral inflammatory profiles, which may be key in the vulnerability to develop metabolic derangements later in life.

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.

Evaluation of the HPA Axis' Response to Pharmacological Challenges in Experimental and Clinical Early-Life Stress-Associated Depression

Early-life stress (ELS) is associated with a higher risk of psychopathologies in adulthood, such as depression, which may be related to persistent changes in the hypothalamic-pituitary-adrenal (HPA) axis. This study aimed to evaluate the effects of ELS on the functioning of the HPA axis in clinical and experimental situations. Clinically, patients with current depressive episodes, with and without ELS, and healthy controls, composed the sample. Subjects took a capsule containing placebo, fludrocortisone, prednisolone, dexamethasone or spironolactone followed by an assessment of plasma cortisol the morning after. Experimentally, male Wistar rats were submitted to ELS protocol based on variable, unpredictable stressors from postnatal day (PND)1 to PND21. On PND65 animals were behaviorally evaluated through the forced-swimming test (FST). At PND68, pharmacological challenges started, using mifepristone, dexamethasone, spironolactone, or fludrocortisone, and corticosterone levels were determined 3 h after injections. Cortisol response of the patients did not differ significantly from healthy subjects, regardless of their ELS history, and it was lower after fludrocortisone, prednisolone, and dexamethasone compared with placebo, indicating the suppression of plasma cortisol by all these treatments. Animals exposed to ELS presented altered phenotype as indicated by an increased immobility time in the FST when compared with control, but no significant long-lasting effects of ELS were observed on the HPA axis response. Limitations on the way the volunteers were sampled may have contributed to the lack of ELS effects on the HPA axis, pointing out the need for further research to understand these complex phenomena.

Effects of prenatal stress on neuroactive steroid responses to acute stress in adult male and female rats

Acute swim stress results in the robust production of several neuroactive steroids, which act as mediators of the stress response. These steroids include glucocorticoids, and positive GABAA receptor modulatory steroids such as allopregnanolone and tetrahydrocorticosterone (THDOC), which potentiate inhibitory GABA signalling, thereby playing a role in the negative control of the hypothalamic-pituitary-adrenal (HPA) axis. Prenatally stressed (PNS) offspring exhibit increased vulnerability to stress-related disorders and frequently display exaggerated HPA axis responses to stressors during adulthood, which may be a result of reduced neuroactive steroid production and consequently inhibitory signalling. Here, we investigated whether exposure of rats to prenatal social stress from gestational day 16-20 altered neuroactive steroid production under non-stress conditions and in response to an acute stressor (swim stress) in adulthood. Using liquid chromatography-mass spectrometry, nine neuroactive steroids were quantified (corticosterone, deoxycorticosterone [DOC], dihydrodeoxycorticosterone, THDOC, progesterone, dihydroprogesterone, allopregnanolone, pregnenolone, testosterone) in plasma and in five brain regions (frontal cortex, hypothalamus, amygdala, hippocampus, brainstem) of male and female control and PNS rats. There was no difference in the neuroactive steroid profile between control and PNS rats under basal conditions. The increase in circulating corticosterone induced by acute swim stress was similar in control and PNS offspring. However, greater stress-induced corticosterone and DOC concentrations were observed in the brainstem of male PNS offspring, whereas DOC concentrations were lower in the hippocampus of PNS females compared to controls, following acute stress. Although PNS rats did not show deficits in allopregnanolone responses to acute stress, there were modest deficits in the production of THDOC in the brainstem, amygdala, and frontal cortex of PNS males and in the frontal cortex of PNS females. The data suggest that neuroactive steroid modulation of GABAergic signalling following stress exposure may be affected in a sex- and region-specific manner in PNS offspring.

Early-Life Stress Alters Synaptic Plasticity and mTOR Signaling: Correlation With Anxiety-Like and Cognition-Related Behavior

Early-life stress (ELS) predisposes individuals to psychiatric disorders, including anxiety and depression, and cognitive impairments later in life. However, the underlying molecular mechanisms are not completely understood. Developmental deficits in hippocampal synaptic plasticity are among the primary detrimental alterations in brain function induced by ELS. Impaired synaptic plasticity is usually accompanied by decreased synaptic proteins, such as postsynaptic density 95 (PSD95) and synaptophysin, which are important for synaptic function. The mTOR signaling pathway plays a vital role in regulating protein translation, and mTOR activation is functionally associated with synaptic protein synthesis. In the present study, we observed whether ELS impacts synaptic protein synthesis and mTOR signaling, which is involved in synaptic plasticity. Herein, we established a maternal separation (MS) and chronic restraint stress (CRS) model and evaluated anxiety-like behavior and cognitive function (e.g., learning and memory) in adulthood through behavioral examination and analyzed hippocampal expression levels of PSD95 and synaptophysin. To explore whether the mTOR signaling pathway was associated with ELS, we also examined the activity of mTOR and s6. The behavior tests indicated that maternally separated mice showed increased anxiety-like behavior and cognitive impairments. PSD95 and synaptophysin mRNA and protein expression levels were decreased in the hippocampus, and phosphorylated mTOR and phosphorylated s6 were significantly decreased in maternally separated mice vs. those not exposed to MS. Our data demonstrate that MS impairs synaptic plasticity and inhibits mTOR signaling, specifically via s6. Therefore, we speculate that ELS decreased synaptic plasticity via the inhibition of the mTOR pathway in the hippocampus, which may underlie vulnerability to stress and mental disorders in adulthood.

The Ontogeny of Hippocampus-Dependent Memories

The formation of memories that contain information about the specific time and place of acquisition, which are commonly referred to as "autobiographical" or "episodic" memories, critically relies on the hippocampus and on a series of interconnected structures located in the medial temporal lobe of the mammalian brain. The observation that adults retain very few of these memories from the first years of their life has fueled a long-standing debate on whether infants can make the types of memories that in adults are processed by the hippocampus-dependent memory system, and whether the hippocampus is involved in learning and memory processes early in life. Recent evidence shows that, even at a time when its circuitry is not yet mature, the infant hippocampus is able to produce long-lasting memories. However, the ability to acquire and store such memories relies on molecular pathways and network-based activity dynamics different from the adult system, which mature with age. The mechanisms underlying the formation of hippocampus-dependent memories during infancy, and the role that experience exerts in promoting the maturation of the hippocampus-dependent memory system, remain to be understood. In this review, we discuss recent advances in our understanding of the ontogeny and the biological correlates of hippocampus-dependent memories.

Unexpected Transcriptional Programs Contribute to Hippocampal Memory Deficits and Neuronal Stunting after Early-Life Adversity

Early-life adversity (ELA) is associated with lifelong memory deficits, yet the responsible mechanisms remain unclear. We impose ELA by rearing rat pups in simulated poverty, assess hippocampal memory, and probe changes in gene expression, their transcriptional regulation, and the consequent changes in hippocampal neuronal structure. ELA rats have poor hippocampal memory and stunted hippocampal pyramidal neurons associated with ~140 differentially expressed genes. Upstream regulators of the altered genes include glucocorticoid receptor and, unexpectedly, the transcription factor neuron-restrictive silencer factor (NRSF/REST). NRSF contributes critically to the memory deficits because blocking its function transiently following ELA rescues spatial memory and restores the dendritic arborization of hippocampal pyramidal neurons in ELA rats. Blocking NRSF function in vitro augments dendritic complexity of developing hippocampal neurons, suggesting that NRSF represses genes involved in neuronal maturation. These findings establish important, surprising contributions of NRSF to ELA-induced transcriptional programming that disrupts hippocampal maturation and memory function.

Early-life stress altered pancreatic Krebs cycle-related enzyme activities in response to young adulthood physical and psychological stress in male rat offspring

OBJECTIVES

Early-life stress (ELS) increases the risk of metabolic disorders in later life. The present study investigated the ELS effect on pancreatic pyruvate dehydrogenase (PDH) protein level, α-ketoglutarate dehydrogenase (α-KGDH), and aconitase activities as metabolic enzymes in response to young adulthood stress in male rat offspring.

METHODS

Male Wistar rats were divided into six groups: Control, early life stress (Early STR), young adult foot-shock stress (Y. adult F-SH STR), early + young adult foot-shock stress (Early + Y. adult F-SH STR), young adult psychological stress (Y. adult Psy STR) and early + young adult psychological stress (Early + Y. adult Psy STR). Stress was induced by a communication box at 2 weeks of age and young adulthood for five consecutive days. The blood samples were collected in young adult rats, then pancreases were removed to measure its PDH protein level and aconitase and α-KGDH activities.

RESULTS

In ELS animals, applying foot-shock stress in young adulthood increased PDH protein level, decreased α-KGDH and aconitase activities, and increased plasma glucose, insulin, and corticosterone concentrations. However, exposure to young adulthood psychological stress only decreased α-KGDH and aconitase activities.

CONCLUSIONS

It seems that ELS altered metabolic response to young adulthood stress through changes of Krebs cycle-related enzymes activities, though the type of adulthood stress was determinant.