Early Life Stress Research Articles

Feasibility of Stress Research in Premature Infant-Maternal Dyads During and After Neonatal Intensive Care Unit Hospitalization.

Stress from preterm infant admission to the neonatal intensive care unit (NICU) is associated with infant and maternal physiologic changes, including endocrine and epigenetic alterations. Little is known about the mechanisms connecting NICU stress to biologic changes, and whether preterm infant and maternal stress are reciprocal. As a preliminary step, feasibility and acceptability of measuring indicators of stress are required. This study evaluated the feasibility and acceptability of research examining perceptions and biologic markers of stress in premature infant-maternal dyads during and after NICU hospitalization. We evaluated study feasibility using a longitudinal descriptive design. Acceptability was measured via a maternal questionnaire. Exploratory data regarding hospitalization, perceptions of stress, social support and social determinants of health, and biologic markers of stress were collected during the first week of life and again 3 months after NICU. Forty-eight mothers were eligible for the study, 36 mothers were approached, 20 mothers consented to participate, and 14 mothers completed data collection. Mothers reported high levels of study acceptability despite also voicing concern about the sharing of genetic data. Exploration of DNA methylation of SLC6A4 in preterm infants was significant for a strong correlation with perception of total chronic stress. Clinical practice at the bedside in the NICU should include standardized screening for and early interventions to minimize stress. Complex research of stress is feasible and acceptable. Future research should focus on linking early life stress with epigenetic alterations and evaluation of the dyad for reciprocity.

Maternal separation modifies spontaneous synaptic activity in the infralimbic cortex of stress-resilient male rats.

Glutamate and GABA signaling systems are necessary to maintain proper function of the central nervous system through excitation/inhibition (E/I) balance. Alteration of this balance in the medial prefrontal cortex (mPFC), as an effect of early-life stress, may lead to the development of anxiety and depressive disorders. Few studies exist in the infralimbic division of the mPFC to understand the effect of early-life stress at different ages, which is the purpose of the present work. Newborn Sprague Dawley male rats were subjected to maternal separation (MS) for two weeks. First, tests measuring anxiety- and depression-like behaviors were performed on adolescent and adult rats subjected to MS (MS-rats). Then, to establish a relationship with behavioral results, electrophysiological recordings were performed in neurons of the infralimbic cortex in acute brain slices of infant, adolescent, and adult rats. In the behavioral tests, there were no significant differences in MS-rats compared to control rats at any age. Moreover, MS had no effect on the passive membrane properties nor neuronal excitability in the infralimbic cortex, whereas spontaneous synaptic activity in infralimbic neurons was altered. The frequency of spontaneous glutamatergic synaptic events increased in infant MS-rats, whereas in adolescent MS-rats both the frequency and the amplitude of spontaneous GABAergic events increased without any effect on glutamatergic synaptic responses. In adult MS-rats, these two parameters decreased in spontaneous GABAergic synaptic events, whereas only the frequency of glutamatergic events decreased. These data suggest that rats subjected to MS did not exhibit behavioral changes and presented an age-dependent E/I imbalance in the infralimbic cortex, possibly due to differential changes in neurotransmitter release and/or receptor expression.

Abstract 16692: Early Life Stress Elicits Heart Failure Traits Across Generations in Mice

Introduction: Adverse childhood experiences, particularly early life stress (ELS), are associated with cardiovascular disease later in life but the underlying mechanisms remain elusive. Parental life experiences can have effects that are transmitted to the offspring suggesting a possible trans-generational transmission of ELS phenotypic traits. Hypothesis: ELS can impair cardiac function in exposed parents and their offspring. Methods: We used an ELS mouse model based on unpredictable separation of mouse pups (F1) from their mother (F0) each day for 3 hours from postnatal day 1 (PND1) to PND14 combined with dams exposure to an additional unpredictable stressor (forced swim in 18°C water for 5 minutes or 20-minute physical restraint in a tube) during separation. Control litters were raised normally. Echocardiography (Vevo 3100, Visualsonics) was performed at 6, 12 and 18 months in exposed animals (F0), their unexposed offspring (F1) and grand-offspring (F2). Both male and female mice were studied. Heart weight/tibia length was used to assess cardiac mass while Masson's Trichrome was employed to detect fibrosis. Lung congestion was assessed as lung wet/dry weight ratio. Single-cell RNA sequencing (scRNAseq) was performed in MSUS and control hearts. A 6-week environmental enrichment (EE) program (cages containing running wheels, maze) was employed to test the possible rescue of ELS effects in adult males and their offspring. Results: Male and female MSUS mice (F1) displayed a time-dependent deterioration (from 6 to 18 months) of LV hypertrophy, diastolic function, myocardial fibrosis and lung congestion when compared to controls. ScRNAseq revealed dysregulation of genes controlling inflammation and metabolism (Cav1, Fabp4) in cardiomyocyte and endothelial cell clusters. MSUS F1 and F2 females and males had diastolic dysfunction and lung congestion at 12 and 18 months (no change at 6 months). Notably, EE improved diastolic function and lung congestion in MSUS mice. Conclusions: ELS induces heritable cardiac alterations which can be rescued by EE in fathers. These results shed light on the causal role of ELS on heart failure development and potential mitigation strategies.

Capsaicin alleviates neuronal apoptosis and schizophrenia-like behavioral abnormalities induced by early life stress

Early life stress (ELS) is associated with the later development of schizophrenia. In the rodent model, the maternal separation (MS) stress may induce neuronal apoptosis and schizophrenia-like behavior. Although the TRPV1 agonist capsaicin (CAP) has been reported to reduce apoptosis in the central nervous system, its effect in MS models is unclear. Twenty-four hours of MS of Wistar rat pups on postnatal day (PND9) was used as an ELS. Male rats in the adult stage were the subjects of the study. CAP (1 mg/kg/day) intraperitoneal injection pretreatment was undertaken before behavioral tests for 1 week and continued during the tests. Behavioral tests included open field, novel object recognition, Barnes maze test, and pre-pulse inhibition (PPI) test. MS rats showed behavioral deficits and cognitive impairments mimicking symptoms of schizophrenia compared with controls. MS decreased the expression of TRPV1 in the frontal association cortex (FrA) and in the hippocampal CA1, CA3, and dentate gyrus (DG) regions compared with the control group resulting in the increase of pro-apoptotic proteins (BAX, Caspase3, Cleaved-Caspase3) and the decrease of anti-apoptotic proteins (Bcl-2). The number of NeuN++TUNEL+ cells increased in the MS group in the FrA, CA1, CA3, and DG compared with the control group. Neuronal and behavioral impairments of MS were reversed by treatment with CAP. Exposure to ELS may lead to increased neuronal apoptosis and impaired cognitive function with decreased TRPV1 expression in the prefrontal cortex and hippocampus in adulthood. Sustained low-dose administration of CAP improved neuronal apoptosis and cognitive function. Our results provide evidence for future clinical trials of chili peppers or CAP as dietary supplements for the reversal treatment of schizophrenia.

Early life stress aggravates disease pathogenesis in mice with experimental autoimmune encephalomyelitis: Support for a two-hit hypothesis of multiple sclerosis etiology

Vision problems are one of the earliest diagnosed symptoms of multiple sclerosis (MS). The onset and progression of vision loss and the underlying pathogenesis in MS may be influenced by cumulative psychophysiological stress. Here, we used a two-hit model of stress in female mice to determine if early life stress (ELS, the first hit) influences the response to an immunization that induces experimental autoimmune encephalomyelitis (EAE, the second hit) later in life. We hypothesized that ELS caused by animal transportation from a vendor during early postnatal development represents a co-factor which can exacerbate the clinical severity of EAE. Indeed, adult EAE mice with a history of ELS displayed more severe clinical signs and delayed recovery compared to non-stressed EAE mice. ELS also diminished visual acuity measured by optokinetic responses, as well as locomotion and exploratory behaviours in EAE mice. Notably, ELS accelerated vision loss and caused earlier onset of visual impairments in EAE. Exacerbated functional impairments in stressed EAE mice were highly correlated with circulating corticosterone levels. The findings show that the progression of induced EAE in adulthood can be significantly impacted by adverse early life experiences. These observations emphasize the importance of comprehensive behavioural testing, including non-motor functions, to enhance the translational value of preclinical animal models of MS. Moreover, shipment stress of laboratory animals should be considered a necessary variable in preclinical MS research. The consideration of cumulative lifetime stresses provides a new perspective of MS pathogenesis within a personalized medicine framework.

Sexually dimorphic effects of a modified adolescent social isolation paradigm on behavioral risk factors of alcohol use disorder in Long Evans Rats

Early life stress (ELS) is a major risk factor for alcohol use disorder (AUD) and comorbid neuropsychiatric conditions. We previously demonstrated that an adolescent social isolation (aSI) model of ELS significantly increased behavioral risk factors for these disorders (e.g. anxiety-like behaviors, alcohol drinking) in male, but not female rats. Since many neurodevelopmental milestones are accelerated in females, we investigated whether an earlier/shorter isolation window (PND 21-38) would yield comparable phenotypes in both sexes. In two experiments, Long Evans rats were socially isolated (SI) or group-housed (GH) on postnatal day (PND) 21 and locomotion was assessed in the open field test (OFT; PND 30). Experiment 1 also assessed behavior on the elevated plus-maze (EPM) (PND 32). In Experiment 2, all rats were single housed on PND 38 to assess home cage alcohol drinking. Experiment 1 revealed that SI females had increased locomotor activity in the OFT but did not differ from GH subjects on the EPM. The OFT results were replicated in both sexes in Experiment 2 and both male and female SI rats had significantly greater ethanol consumption during an eight day continuous access paradigm. In contrast, during subsequent intermittent two-bottle choice drinking, only SI females displayed greater ethanol intake and preference and increased consumption of a quinine-adulterated alcohol solution. These findings demonstrate that early life social isolation can promote AUD vulnerability-related phenotypes in female rats but that there are profound sex differences in the vulnerability window to this early life stressor. Uncovering the neural mechanisms responsible for these sexually dimorphic differences in sensitivity to ELS may shed light on the biological substrates associated with vulnerability to AUD and comorbid disorders of negative emotion in men and women.

Si-Ni-San alleviates early life stress-induced depression-like behaviors in adolescence via modulating Rac1 activity and associated spine plasticity in the nucleus accumbens.

Background: Early life stress (ELS) is a major risk factor for depression in adolescents. The nucleus accumbens (NAc) is a key center of the reward system, and spine remodeling in the NAc contributes to the development of depression. The Si-Ni-San formula (SNS) is a fundamental prescription for treating depression in traditional Chinese medicine. However, little is known about the effects of SNS on behavioral abnormalities and spine plasticity in the NAc induced by ELS. Purpose: This study aimed to investigate the therapeutic effect and the modulatory mechanism of SNS on abnormal behaviors and spine plasticity in the NAc caused by ELS. Methods: We utilized a model of ELS that involved maternal separation with early weaning to explore the protective effects of SNS on adolescent depression. Depressive-like behaviors were evaluated by the sucrose preference test, the tail suspension test, and the forced swimming test; anxiety-like behaviors were monitored by the open field test and the elevated plus maze. A laser scanning confocal microscope was used to analyze dendritic spine remodeling in the NAc. The activity of Rac1 was detected by pull-down and Western blot tests. Viral-mediated gene transfer of Rac1 was used to investigate its role in ELS-induced depression-like behaviors in adolescence. Results: ELS induced depression-like behaviors but not anxiety-like behaviors in adolescent mice, accompanied by an increase in stubby spine density, a decrease in mushroom spine density, and decreased Rac1 activity in the NAc. Overexpression of constitutively active Rac1 in the NAc reversed depression-related behaviors, leading to a decrease in stubby spine density and an increase in mushroom spine density. Moreover, SNS attenuated depression-like behavior in adolescent mice and counteracted the spine abnormalities in the NAc induced by ELS. Additionally, SNS increased NAc Rac1 activity, and the inhibition of Rac1 activity weakened the antidepressant effect of SNS. Conclusion: These results suggest that SNS may exert its antidepressant effects by modulating Rac1 activity and associated spine plasticity in the NAc.

Striatal TSPO binding is associated with anhedonia severity and early life stress exposure in anhedonic patients with major depressive disorder

Striatal TSPO binding is associated with anhedonia severity and early life stress exposure in anhedonic patients with major depressive disorder

Early life stress lastingly alters the function and AMPA-receptor composition of glutamatergic synapses in the hippocampus of male mice.

Early postnatal life is a sensitive period of development that shapes brain structure and function later in life. Exposure to stress during this critical time window can alter brain development and may enhance the susceptibility to psychopathology and neurodegenerative disorders later in life. The developmental effects of early life stress (ELS) on synaptic function are not fully understood, but could provide mechanistic insights into how ELS modifies later brain function and disease risk. We here assessed the effects of ELS on synaptic function and composition in the hippocampus of male mice. Mice were subjected to ELS by housing dams and pups with limited bedding and nesting material from postnatal days (P) 2-9. Synaptic strength was measured in terms of miniature excitatory postsynaptic currents (mEPSCs) in the hippocampal dentate gyrus at three different developmental stages: the early postnatal phase (P9), preadolescence (P21, at weaning) and adulthood at 3 months of age (3MO). Hippocampal synaptosome fractions were isolated from P9 and 3MO tissue and analyzed for protein content to assess postsynaptic composition. Finally, dendritic spine density was assessed in the DG at 3MO. At P9, ELS increased mEPSC frequency and amplitude. In parallel, synaptic composition was altered as PSD-95, GluA3 and GluN2B content were significantly decreased. The increased mEPSC frequency was sustained up to 3MO, at which age, GluA3 content was significantly increased. No differences were found in dendritic spine density. These findings highlight how ELS affects the development of hippocampal synapses, which could provide valuable insight into mechanisms how ELS alters brain function later in life.

205 Relationship of Resiliency to Weaning Stress with Growth, Carcass, and Meat Quality Traits in Pigs

Abstract Acute stress before slaughter has been demonstrated to have a detrimental impact on pork quality, but little is known about whether early life stress has a similar effect. Our objective was to identify if stress resiliency or vulnerability at weaning had an impact on long-term performance resulting in differences in growth, carcass, or meat quality traits. At weaning, blood samples were collected from all gilt piglets from 26 crossbred litters (n = 170) at -1 d, 0 d, and +4 d pre- and post-weaning. For each litter, serum cortisol was used to identify the gilt most capable of returning to baseline levels by +4 d as stress resilient (SR, n = 26) and the gilt least capable as stress vulnerable (SV, n = 26). The SR and SV gilts were processed at the Michigan State University Meat Laboratory and carcass and meat quality data were collected. Carcass traits included finished live weight, hot carcass weight, dressing percentage, loin muscle area, and 10th-rib backfat depth. Meat quality traits included 45-min and ultimate pH, marbling score, subjective color score, Minolta colorimeter L*, a* and b*, and drip loss. Data were analyzed using Gaussian linear models. The base model included stress group and farrowing group as fixed effects and age at slaughter as a covariate. The SR gilts showed decreased ADG at the grow-finish stage resulting in lighter finished weight (P = 0.089 and P = 0.070, respectively). The SR gilts also had a lighter hot carcass weight (P = 0.05); however, no differences were observed in dressing percentage ( P= 0.924). the SR and SV gilts did not differ in backfat depth, but SR gilts had smaller loin muscle area (P = 0.019). No differences were observed in any of the meat quality measures. In summary, we found resiliency to weaning stress to have a minimal impact on carcass merit or meat quality. Future studies will aim to determine if the observed difference in loin muscle area is associated with gene expression differences.

PSV-8 Early Life Adversity Impacts Intestinal Epithelial Development and Stem Cells Activities in Pigs

Abstract Early life adversity significantly impacts organ development and predisposes animals towards greater risk of diseases later in life. In the previous research in pigs, long lasting intestinal barrier dysfunctions have been found to be associated with early weaning stress. However, the underlying mechanism is not fully elucidated. Intestinal epithelial functions are associated with the number and maturation of multicellular components, including enterocytes, goblet cells, Paneth cells, and enteroendocrine cells (EEC). Intestinal epithelial stem cells (IESC) give rise to the whole epithelium within 5 to 7 days. Such rapid turnover rate allows intestinal adaptation to stress conditions. We hypothesized that the early life stress impacted stem cells activities which would contribute to the long-lasting post-stress functional changes in intestinal epithelium. The objective of the present study is to evaluate the epithelium component cells and IESC proliferation and differentiation activities in an early weaning stress model in pigs. Piglets (n = 18) were obtained from commercial litters and were pair-weaned at the age of d 15 (early weaning, EW) and d 26 (late weaning, LW). Piglets were co-housed and raised under the same conditions. At the age of d 35, ileal tissues were isolated and fixed for morphological measurements. Intestinal crypts were isolated and cultured in the Matrigel matrix to form enteroids. The proliferation activities of IESCs were measured by enteroids morphology; differentiation capacity was measured by quantification of epithelial cell markers with and without chemicals-induced enteroids differentiation. Gene expressions and (or) staining of specific markers for IESCs (Olfm4, BMI1), enterocytes (ALP1), goblet cells (Muc2), Paneth cells (LYZ), and EECs (ChgA) in ileal tissue and ileal enteroids were also quantified. Data were analyzed by the student’s t-test. Our results showed that EW significantly (P < 0.05) reduced ileal villus width and crypt fission rate, while no changes were found on villus height and crypt depth compared with LW control. The alterations of ileal epithelium components in EW pigs were indicated by significantly fewer number of EECs, greater number of the goblet cells, and reduced ALP1 marker expression. The enteroids formation and budding rates were both significantly suppressed in EW pigs, which indicated a reduced IESC proliferating activity. In the fully developed enteroids, gene expressions of LYZ, ALP1, BMI1, Olfm4, and Hes1 were least in EW, but Muc2 expression was greater compared with control. In the differentiation culture media, the enteroids from EW pigs exhibited significantly enhanced potential for goblet cell differentiation but reduced capacity for enterocyte differentiation compared with LW pigs. Overall, the results indicate that early weaning stress affects the programming and activity of IESCs, which leads to an altered epithelium cell population and intestinal functions. Further understanding of mechanisms regulating IESCs activity will shed light on novel strategies mitigating stress-associated intestinal dysfunctions.

5 DPP Lecture: Investigating the Impact of Weaning and Biological Sex on Gut Development: Discovering New Targets for Gut Inflammation

Abstract Early life stress is known to have a profound impact on the development and function of the gut and immune system in various species, including pigs. In particular, the process of weaning is a significant source of stress in pigs and has been shown to negatively affect gut health and immunity. This presentation aims to examine the current knowledge on the impact of early life stress, particularly weaning, on gut development and immunity in pigs with a focus on chronic inflammation as a driver of disease risk. The presentation will also compare the immune system and gut development between female and male castrates, highlighting the influence of biological sex on gut health. Additionally, new data on potential targets for gut inflammation will be presented. The findings of this presentation will be analyzed in the context of pig production and the implications for enhancing gut health and immunity throughout production. Overall, this presentation will provide a comprehensive overview of the current understanding of the impact of early life stress on gut development and immunity in pigs and highlights key areas for future research.

Pituitary gland volumes and stress: Results of a population-based adult sample

Early and chronic stress was reported to alter the hypothalamic-pituitary-adrenal axis functioning which regulates the secretion of cortisol. Nevertheless, few studies mainly focused on specific study populations (e.g. adolescents, pregnant women, and psychiatric patients), and researched interactive associations of pituitary volumes and single stress markers. The present study used pituitary volumes of two adult general-population cohorts of the Study of Health in Pomerania (SHIP-START-2: N = 1026, 54% Men, 30–90 years; SHIP-TREND-0: N = 1868, 53% Men, 21–82 years). In linear regression models, main effects of the pituitary volumes as well as interaction effects with childhood abuse and neglect (Childhood Trauma Questionnaire) were estimated using depressive symptoms (Beck Depression Inventory-II), and serum cortisol concentrations as outcome variables. The results of both cohorts were integrated via meta-analyses. No main effect between pituitary volumes and depressive symptoms was observed (START-2: β = −0.004 [-0.082; 0.075], p = .929; TREND-0: β = 0.020 [-0.033; 0.073], p = .466; Meta-analysis: β = 0.012 [-0.031; 0.056], p = .580). However, larger pituitary volumes were associated with more depressive symptoms in participants with more severe childhood neglect (START-2: β = 0.051 [-0.024; 0.126], p = .183; TREND-0: β = 0.083 [0.006; 0.159], p = .034; Meta-analysis: β = 0.066 [0.013; 0.120], p = .015). Further, larger pituitary volumes were associated with lower serum cortisol concentrations in participants with more severe depressive symptoms (START-2: β = −0.087 [-0.145; −0.030], p = .003; TREND-0: β = −0.053 [-0.091; −0.015], p = .006; Meta-analysis: β = −0.063 [-0.095; −0.032], p = 8.39e-05). Summarizing, larger pituitary volumes were associated with more severe psychopathological symptoms, particularly in participants reporting early life stress. This was supported by stronger associations between pituitary volumes and cortisol concentrations in participants with more severe depressive symptoms. Future studies are needed to transfer these results into developmental stages of high hormonal changes and patient samples.

29 Evaluation of Diet Composition on Early Post-Weaned Feed Intake and Intestinal Health

Abstract Weaning is an inevitable early life stressor in commercial production that can cause an immediate reduction in voluntary feed intake and growth during a critical period of gastrointestinal development. Further, the reduction in voluntary feed intake is strongly correlated with the risk of disease during that period. Therefore, our objective was to test the effect of different dietary interventions on early nursery pig feed intake, performance, fecal consistency, and histological parameters. Over 2 repetitions, a total of 90 newly weaned gilts (19-21 d of age, BW 5.62 ± 1.1 kg) were selected, individually penned and randomly assigned to 1 of 5 dietary treatments (n = 18 pigs/treatment) that included: 1) Control diet (CON), 2) CON + 5% sugar beet pulp (BP), 3) CON + 10% high fructose corn syrup (HFCS), 4) CON + 5% soyhulls (SH), or 5) CON + 3,000 ppm Zn and 200 ppm Cu (d 0-7), and 2,000 ppm Zn and 200 ppm Cu (d 8-14; ZC). Each repetition was conducted over a 14-d period consisting of 2 phases (Phase 1: d 0-7, phase 2: d 8-14). Pigs were all sourced from a natural endemic enteric pathogen positive nursery flow and confirmed positive for rotavirus, coccidia and F18 E. coli. Fecal consistency was scored and feed disappearance was recorded daily. On d 0, 7 and 14, pig BW were collected. Weekly feed disappearance and BW were used to calculate ADG, ADFI and feed efficiency (G:F) within phase and overall. On d 14, all pigs were euthanized, and fixed sections of ileum and colon were collected to assess histopathology including incidence of villus atrophy and colitis. Pig was the experimental unit, and performance and histology data were analyzed by dietary treatment. Daily measures of feed intake were analyzed by repeated measures with the fixed effects of diet, day, and their interaction. Starting BW did not differ across dietary treatments (P = 0.845). Over the 14-d test period, HFCS and ZC treatments tended to increase ADG (0.20 and 0.15 kg/d, respectively) compared with CON, BP and SH (0.09, 0.12, and 0.13 kg/d, respectively; P = 0.076). Further, the addition of a sweetener (HFCS) did not improve daily feed intake, while SH reduced daily feed intakes by 32% compared with all other treatments (P < 0.001). Although all pigs had some degree of diarrhea, fecal consistency did not differ between dietary treatments (P = 0.618). Histopathology scoring for intestinal atrophy (ileum) and colitis (colon) were not different (P = 0.645 and 0.440, respectively). In conclusion, the addition of BP, HFCS, SH and ZC had an effect on growth and feed intake but there was no benefit in atrophy, colitis, and fecal scores when encountering a natural enteric pathogen burden.

The relation between preterm birth and self-reported spinal pain in pre-adolescence—a study of 47,063 subjects from the Danish National Birth Cohort

Repeated exposure to pain and stress in early life may cause alterations in pain sensitivity later in life. Children born preterm are often exposed to painful invasive procedures. This study aimed to explore the relationship between being born preterm and self-report of spinal pain in pre-adolescence. This prospective study was based on the Danish National Birth Cohort and consisted of 47,063 11–14-year-olds. Data from the Danish National Birth Cohort were linked with national registers through Statistics Denmark. Analyses were performed as multiple logistic regression models estimating odds ratios and 95% confidence intervals. Spinal pain (neck, mid back, and/or low back pain) was assessed using a subdivision of the Young Spine Questionnaire. Severe spinal pain was defined as having pain often or once in a while with an intensity of four to six on the Revised Faces Pain Scale. Inverse probability weighting was used to account for potential selection bias. Girls born very preterm (< 34 full weeks of gestation) were less likely to report spinal pain (OR: 0.60; 95% CI: 0.40–0.93) compared with those term-born. The associations were weaker when examining moderate to severe spinal pain and when examining the three spinal regions separately. None of these was statistically significant.Conclusion: We found no associations for boys. In conclusion, this study indicates that girls born very preterm are seemingly less likely to have severe spinal pain in pre-adolescence than girls born at term.What is Known:• Spinal pain is one of the largest disease burdens globally, and the evidence regarding the etiology of spinal pain in children and adolescents is limited.• Repeated exposure to pain and stress in early life (i.e., being preterm) may cause alterations in pain sensitivity later in life.What is New:• Girls born very preterm (< 34 full weeks of gestation) seem less likely to report severe spinal pain in pre-adolescence compared with girls born at full term.• There is no association between gestational age and later experience of spinal pain in pre-adolescent boys.

The impact of early life stress and schizophrenia on motor and cognitive functioning: an experimental study

BackgroundEarly life stress (ELS) and parental psychopathology, such as schizophrenia (SZ), have been associated with altered neurobiological and behavioral outcomes later in life. Previous studies have investigated the effects of ELS and parental SZ on various aspects of behavior, however, we have studied the combined effects of these stressors and how they interact, as individuals in real-life situations may experience multiple stressors simultaneously.ObjectiveThe aim of this study was to investigate the impact of ELS and schizophrenia on locomotor activity, anxiety-like behavior, exploratory tendencies, and spatial memory in Sprague Dawley (SD) rats.MethodsMale and female SD pups were randomly assigned to eight groups: control, ELS, schizophrenia, and ELS + schizophrenia. ELS was induced by prenatal stress (maternal stress) and maternal separation (MS) during the first 2 weeks of life, while SZ was induced by subcutaneous administration of ketamine. Behavioral tests included an open field test (OFT) for motor abilities and a Morris water maze (MWM) for cognitive abilities. ANOVA and post hoc Tukey tests were utilized to analyze the data.ResultsOur results show that ELS and parental psychopathology had enduring effects on SZ symptoms, particularly psychomotor retardation (p &amp;lt; 0.05). The OFT revealed increased anxiety-like behavior in the ELS group (p = 0.023) and the parental psychopathology group (p = 0.017) compared to controls. The combined ELS and parental psychopathology group exhibited the highest anxiety-like behavior (p = 0.006). The MWM analysis indicated impaired spatial memory in the ELS group (p = 0.012) and the combined ELS and parental psychopathology group (p = 0.003) compared to controls. Significantly, the exposure to ELS resulted in a decrease in the population of glial fibrillary acidic protein-positive (GFAP+) astrocytes. However, this effect was reversed by positive parental mental health.ConclusionOur findings highlight the interactive effects of ELS and parental psychopathology on anxiety-like behavior and spatial memory in rats. ELS was linked to increased anxiety-like behavior, while SZ was associated with anhedonia-like behavior. Positive parenting augments neuroplasticity, synaptic function, and overall cognitive capacities.

Dehydroepiandrosterone mediates associations between trauma-related symptoms and anterior pituitary volume in children and adolescents.

The anterior pituitary gland (PG) is a potential locus of hypothalamic-pituitary-adrenal (HPA) axis responsivity to early life stress, with documented associations between dehydroepiandrosterone (DHEA) levels and anterior PG volumes. In adults, elevated anxiety/depressive symptoms are related to diminished DHEA levels, and studies have shown a positive relationship between DHEA and anterior pituitary volumes. However, specific links between responses to stress, DHEA levels, and anterior pituitary volume have not been established in developmental samples. High-resolution T1-weighted MRI scans were collected from 137 healthy youth (9-17 years; Mage = 12.99 (SD = 1.87); 49% female; 85% White, 4% Indigenous, 1% Asian, 4% Black, 4% multiracial, 2% not reported). The anterior and posterior PGs were manually traced by trained raters. We examined the mediating effects of salivary DHEA on trauma-related symptoms (i.e., anxiety, depression, and posttraumatic) and PG volumes as well as an alternative model examining mediating effects of PG volume on DHEA and trauma-related symptoms. DHEA mediated the association between anxiety symptoms and anterior PG volume. Specifically, higher anxiety symptoms related to lower DHEA levels, which in turn were related to smaller anterior PG. These results shed light on the neurobiological sequelae of elevated anxiety in youth and are consistent with adult findings showing suppressed levels of DHEA in those with greater comorbid anxiety and depression. Specifically, adolescents with greater subclinical anxiety may exhibit diminished levels of DHEA during the pubertal window, which may be associated with disruptions in anterior PG growth.

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

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. 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. 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. 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.

Possible role of NO/NMDA pathway in the autistic-like behaviors induced by maternal separation stress in mice.

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder. Maternal separation (MS) stress is an established model of early-life stress associated with autistic-like behaviors. Altered glutamatergic and nitrergic neurotransmissions may contribute to the pathophysiology of ASD. However, the specific mechanisms underlying these alterations and their relationship to MS-induced autistic-like behaviors remain unclear. Addressing this knowledge gap, this study aims to elucidate the involvement of the nitric oxide (NO)/ N-methyl-D-aspartate (NMDA) pathway in MS-induced autistic-like behaviors in mice. This knowledge has the potential to guide future research, potentially leading to the development of targeted interventions or treatments aimed at modulating the NO/NMDA pathway to ameliorate ASD symptoms. Ninety male Naval Medical Research Institute (NMRI) mice were assigned to six groups (n = 15) comprising a control group (treated with saline) and five groups subjected to MS and treated with saline, ketamine, NMDA, L-NAME, and L-arginine. Behavioral tests were conducted, including the three-chamber test, shuttle box, elevated plus-maze, and marble burying test. Gene expression of iNOS, nNOS, and NMDA-R subunits (NR2A and NR2B), along with nitrite levels, was evaluated in the hippocampus. The findings demonstrated that MS induced autistic-like behaviors, accompanied by increased gene expression of iNOS, nNOS, NR2B, NR2A, and elevated nitrite levels in the hippocampus. Modulation of the NO/NMDA pathway with activators and inhibitors altered the effects of MS. These results suggest that the NO/NMDA pathway plays a role in mediating the negative effects of MS and potentially contributes to the development of autistic-like behaviors in maternally separated mice.

OR19-01 Srd5a1 Undergoes Distinct Changes in Methylation and Is Differentially Expressed During Pre-Pubertal Development in the Ovary and Hypothalamus

Abstract Disclosure: B. Bar-Sadeh: None. P. Melamed: None. The steroidogenic enzyme, 5α-reductase-1, is responsible for conversion of testosterone to dihydrotestosterone, and production of other 5α-reduced steroids and their derivatives, including in the brain. We reported previously that Srd5a1 levels are reduced in mice hypothalamic preoptic area (POA) and ovaries following early-life immune stress, which appeared to underlie delayed puberty onset and faster depletion of the ovarian reserve. This drop in ovarian Srd5a1 expression was concomitant with hypermethylation at two CpGs in its first intron, and also at the orthologous site in buccal DNA of women who experienced childhood immune challenge1. We thus hypothesized that this region of Srd5a1 acts as a transcriptional enhancer and is regulated by DNA methylation. Here we examined Srd5a1 expression and methylation at these CpGs across normal mouse development and in cultured cells. Ovarian Srd5a1 increased 8-fold and CpG methylation decreased by as much as 75% between PND10-30. During this time estradiol (E2) levels rise, and E2 exposure increased Srd5a1 mRNA levels in primary ovarian cells and KK-1 cell line. Chromatin immunoprecipitation (ChIP) confirmed binding of estrogen receptor to the locus of the CpGs, and identified an adjacent region strongly enriched with H3K4me1, characteristic of transcriptional enhancers. In the POA, in sharp contrast, Srd5a1 mRNA levels decreased by 70% between PND7-10 and then stayed quite constant, with little correlation to CpG methylation levels. The neonatal drop in POA Srd5a1 coincides with an increase in glucocorticoid (GC) levels, and we had seen lower Srd5a1 expression in mice following early-life stress, we thus treated GT1-7 hypothalamic neuronal cells with dexamethasone. This treatment reduced Srd5a1 expression, and ChIP confirmed that the GC receptor binds the enhancer locus. Srd5a1 expression was 12-fold higher in the ovarian KK1 cells compared to the neuronal GT1-7 cells, in accordance with much higher methylation levels in the latter. We thus used these cells to investigate the role of this CpG methylation, using gRNAs targeting dCas9-TET1 for demethylation in GT1-7 cells, or dCas9-DNMT3 for inducing methylation in KK1 cells. In GT1-7 cells, methylation at the first CpG dropped &amp;gt;50%, though was unaltered at the second CpG, and no effect was seen on Srd5a1 expression or its response to E2. In contrast, methylation in KK1 cells increased at the second CpG only, by more than 2.5 fold, and this abolished the response to E2. These distinct changes in Srd5a1 expression during development, together with our findings in cultured cells suggest a cell-specific GC-activated repression of Srd5a1 in the POA, and its E2-activated stimulation in the ovaries regulated by methylation at one of these CpGs. Reference: 1. Bar-Sadeh, B., Amichai, O.E., Pnueli, L., Begum, K., Leeman, G., Emes, R.D., Stöger, R., Bentley, G.R., and Melamed, P. (2022). BMC Biol. 20, 11. Presentation Date: Saturday, June 17, 2023