Effects of maternal psychological stress during pregnancy on offspring brain development: Considering the role of inflammation and potential for preventive intervention

Prenatal sleep restriction altered learning ability and memory behaviour by decreasing hippocampal synaptic plasticity in offspring mice

Inadequate sleep during pregnancy can have profound effects on offspring neurodevelopment, particularly on learning and memory abilities. This study explored whether prenatal sleep restriction (SR) induces learning and memory impairment in offspring by affecting neural plasticity in the hippocampus using four groups of pregnant mice: short-sleep-restriction (S-SR, 4 h), mid-sleep-restriction (M-SR, 10 h), long-sleep-restriction (L-SR, 18 h), and a control group without SR. SR was implemented from gestation day 8 until delivery. Changes in adult offspring and fetal hippocampal synapse structures were observed and synapse-synthesis-related protein (BDNF and Syt7) levels were measured to establish changes indicative of neurodevelopmental impairment. Offspring learning and memory abilities were further evaluated using Morris water maze test, passive avoidance test, and open field test from postnatal day 35. The findings revealed significant declines in spatial learning and memory across all SR groups. Additionally, adult offspring exhibited reduced hippocampal synapse numbers, thinner postsynaptic densities in S-SR and M-SR groups, and widened synaptic clefts in the L-SR group. Synapse-synthesis-related proteins, including brain-derived neurotrophic factor (BDNF) and synaptotagmin-7 (Syt7), showed decreased expression in the hippocampus of offspring mice in all SR groups, with BDNF expression also reduced in fetal hippocampi. Moreover, BDNF methylation levels indicated significant decreases in BDNF_3 and increases in BDNF_5 specifically in the S-SR group. Notably, prenatal S-SR induced more pronounced impairments in offspring learning and memory compared to L-SR. These findings underscore how prenatal SR disrupts fetal neurodevelopment, emphasizing hippocampal synaptic plasticity as a critical mechanism contributing to impaired cognitive function in offspring. This can help with risk identification and early intervention.

Maternal prenatal stress induces sex-dependent changes in tRNA fragment families and cholinergic pathways in newborns

Maternal perceived prenatal stress (PPS) is a known risk factor for diverse developmental impairments in newborns, but the underlying molecular processes are incompletely understood. Here, we report that maternal PPS altered the birth profiles of blood transfer RNA fragments (tRFs), 16-50 nt long non-random cleavage products of tRNAs, in a sex-dependent manner. Importantly, comparing stressed versus control maternal and umbilical cord blood serum presented alterations that were not limited to individual tRFs, but rather reflected selective changes in particular tRF families grouped by their mitochondrial or nuclear genome origin, parental tRNA coded amino acid, and cleavage type. Specifically, tRF families that show stress- and sex-specific effects, revealed shared length and expression patterns which were strongest in the female newborns. Several of these tRFs carry complementary motifs to particular cholinergic mRNAs, suggesting possible translational regulation similar to microRNAs. Compatible with the cholinergic regulation of stress reactions, those "CholinotRFs" achieved an AUC of 95% when classifying female newborns according to maternal PPS. Moreover, we found altered catalytic activity of serum acetylcholinesterase, which was particularly elevated in male newborns, marking a second sex-specific effect. Our findings demonstrate an association of tRF families' patterns with newborns' sex-specific stress response to PPS and may lead to better diagnosis and therapeutic tools for these and other stressors.

Building Better Brains: The Workshop

"Building Better Brains" is a workshop incorporating adult learning principles to educate and motivate participants working with pregnant women and families with young children. The workshop commences with a lecture on early brain development, followed by playing the Brain Architecture Game in small groups. Participants then utilize their experiences to suggest actions that can be taken to their home communities and workplaces to "spread the word" and advocate for "Building Better Brains." Before the workshop, participants submitted their personal goals for the program. Upon the workshop's completion, 25 out of 27 participants responded positively, stating their goals had been met.

From placenta to the foetus: a systematic review of in vitro models of stress- and inflammation-induced depression in pregnancy

BACKGROUND

Depression in pregnancy can increase vulnerability for psychiatric disorders in the offspring, likely via the transfer of heightened maternal cortisol and cytokines to the in-utero environment. However, the precise cellular and molecular mechanisms, are largely unclear. Animal studies can represent this complex pathophysiology at a systemic level but are expensive and ethically challenging. While simpler, in vitro models offer high-throughput opportunities. Therefore, this systematic review integrates findings of in vitro models relevant to depression in pregnancy, to generate novel hypotheses and targets for intervention.

METHODS

The systematic analysis covered studies investigating glucocorticoid or cytokine challenges on placental or foetal neural progenitor cells (NPCs), with or without co-treatment with sex hormones.

RESULTS

Of the 50 included studies, 11 used placental cells and 39 NPCs; surprisingly, only one used a combination of oestrogen and cortisol, and no study combined placental cells and NPCs. In placental cells, cortisol or cytokines decreased nutrient transporter expression and steroidogenic enzyme activity, and increased cytokine production. NPCs exhibited decreases in proliferation and differentiation, via specific molecular pathways, namely, inhibition of hedgehog signalling and activation of kynurenine pathway. In these cells, studies also highlighted epigenetic priming of stress and inflammatory pathways.

CONCLUSIONS

Overall, results suggest that stress and inflammation not only detrimentally impact placental regulation of nutrients and hormones to the foetus, but also activate downstream pathways through increased inflammation in the placenta, ultimately eliciting adverse effects on foetal neurogenesis. Future research should investigate how sex hormones regulate these mechanisms, with the aim of developing targeted therapeutic approaches for depression in pregnancy.

Gut-X axis

Recent advances in understanding the modulatory functions of gut and gut microbiota on human diseases facilitated our focused attention on the contribution of the gut to the pathophysiological alterations of many extraintestinal organs, including the liver, heart, brain, lungs, kidneys, bone, skin, reproductive, and endocrine systems. In this review, we applied the "gut-X axis" concept to describe the linkages between the gut and other organs and discussed the latest findings related to the "gut-X axis," including the underlying modulatory mechanisms and potential clinical intervention strategies.

Center M Pilot Trial: Integrating Preventive Mental Health Care in Routine Prenatal Care

INTRODUCTION

Perinatal depression is a leading cause of preventable US maternal morbidity and mortality. Although Mindfulness-Based Cognitive Therapy for Perinatal Depression (MBCT-PD) is highly effective, it faces significant scalability challenges. Center M, a brief, group-based, mindfulness-based cognitive behavioral therapy (CBT) intervention, is an adaptation of MBCT-PD designed to overcome these challenges. The purpose of this pilot study was to evaluate Center M's preliminary acceptability, feasibility, mechanisms of action, and efficacy.

METHODS

In this mixed-methods pilot study, data were collected from 99 pregnant people at 3 time points: preintervention, postintervention, and 6-weeks postpartum (Clinical Trials no. NCT06525922). Participants engaged in 4 one-hour, weekly group telehealth Center M sessions facilitated by social workers. Participants strengthened mindfulness CBT skills using home practice materials between group sessions. Data included self-report measures evaluating depressive symptoms, mindfulness skills, and emotion regulation. Satisfaction was assessed via focus groups or surveys.

RESULTS

Depressive symptoms significantly decreased preintervention to postintervention (Patient Health Questionnaire-8 score: preintervention mean [SD] 5.02 [3.52], postintervention mean [SD] 4.23 [2.84]; P = .03), and mindfulness capacity significantly increased preintervention to 6 weeks postpartum (Five Facets of Mindfulness Questionnaire score: preintervention mean [SD] 125.56 [18.68], 6 weeks postpartum mean [SD] 130.10 [17.15]; P = .004). Linear regression analyses indicate that higher mindfulness at 6 weeks postpartum significantly predicted fewer depression symptoms at 6 weeks postpartum (β, -0.07; 95% CI, -0.123 to -0.021, R2 = 0.22; P = .006). Reduction in the use of maladaptive emotion regulation was significantly associated with decreased depressive symptoms at 6 weeks postpartum (β, 0.21; 95% CI, 0.048 to 0.376, R2 = .21; P = .012). Qualitative themes indicated high Center M acceptability and appeal.

DISCUSSION

Our findings support the feasibility, acceptability, and appeal of Center M. Results suggest Center M may be effective in reducing depression and enhancing mindfulness skills. Future research must confirm these initial findings to more widely address Center M implementation capacity and sustainability.

The Impact of Mindfulness Treatment on Maternal Inflammation and Fetal Neurodevelopment Among Participants with Histories of Hypertensive Disorders

This was a secondary analysis of a prenatal mindfulness training (MT) RCT versus treatment as usual (TAU) on neutrophil-to-lymphocyte ratio (NLR), a measure of maternal inflammation, and fetal head circumference. Fifteen participants were randomized to MT and 14 to TAU. NLR in third trimester was significantly lower in the MT group (F = 7.11, p = 0.019) relative to those in TAU. Higher NLR values in second (r = -0.644, p = 0.013) and third trimesters (r = -0.601, p = 0.030) were associated with lower fetal HC%. There was no group difference in fetal HC%. A future, fully powered study is needed to replicate these findings. Clinical Trials Number: NCT03679117.

Impact of Stress on Brain Morphology: Insights into Structural Biomarkers of Stress-related Disorders

Exposure to acute and chronic stress has a broad range of structural effects on the brain. The brain areas commonly targeted in the stress response models include the hippocampus, the amygdala, and the prefrontal cortex. Studies in patients suffering from the so-called stress-related disorders -embracing post-traumatic stress, major depressive and anxiety disorders- have fairly replicated animal models of stress response -particularly the neuroendocrine and the inflammatory models- by finding alterations in different brain areas, even in the early neurodevelopment. Therefore, this narrative review aims to provide an overview of structural neuroimaging findings and to discuss how these studies have contributed to our knowledge of variability in response to stress and the ulterior development of stress-related disorders. There are a gross number of studies available but neuroimaging research of stress-related disorders as a single category is still in its infancy. Although the available studies point at particular brain circuitries involved in stress and emotion regulation, the pathophysiology of these abnormalities -involving genetics, epigenetics and molecular pathways-, their relation to intraindividual stress responses -including personality characteristics, self-perception of stress conditions…-, and their potential involvement as biomarkers in diagnosis, treatment prescription and prognosis are discussed.

Microglia are necessary for probiotics supplementation to improve impaired fear extinction caused by pregnancy stress in adult offspring of rats

The prevention and treatment of fear-related disorders in offspring affected by pregnancy stress remains challenging at clinic. Here, we examined the effects of gut microbiota of stressed pregnant rats on the fear extinction of their offsprings, and the potential mechanisms. We found that gut microbiota transplantation from rats with pregnancy stress to normal pregnant rats impaired fear extinction, induced microglial activation and synaptic phagocytosis, increased synapse loss in offsprings. Probiotics supplement during pregnancy stress partly normalized pregnancy stress-induced gut microbiota dysbiosis of pregnant rats, and promoted fear memory extinction, inhibited fear memory reappearance, and limited microglial activation and synaptic phagocytosis in offsprings. These data revealed that gut microbiota of stressed pregnant mother improved the development of fear-related disorders of offspring, which may be associated with microglial synaptic pruning.

Placental inflammatory cytokines mRNA expression and preschool children's cognitive performance: a birth cohort study in China

BACKGROUND

The immunologic milieu at the maternal-fetal interface has profound effects on propelling the development of the fetal brain. However, accessible epidemiological studies concerning the association between placental inflammatory cytokines and the intellectual development of offspring in humans are limited. Therefore, we explored the possible link between mRNA expression of inflammatory cytokines in placenta and preschoolers' cognitive performance.

METHODS

Study subjects were obtained from the Ma'anshan birth cohort (MABC). Placental samples were collected after delivery, and real-time quantitative polymerase chain reaction (RT-qPCR) was utilized to measure the mRNA expression levels of IL-8, IL-1β, IL-6, TNF-α, CRP, IFN-γ, IL-10, and IL-4. Children's intellectual development was assessed at preschool age by using the Wechsler Preschool and Primary Scale of Intelligence, Fourth Edition (WPPSI-IV). Multiple linear regression and restricted cubic spline models were used for statistical analysis.

RESULTS

A total of 1665 pairs of mother and child were included in the analysis. After adjusting for confounders and after correction for multiple comparisons, we observed that mRNA expression of IL-8 (β =  - 0.53; 95% CI, - 0.92 to - 0.15), IL-6 (β =  - 0.58; 95% CI, - 0.97 to - 0.19), TNF-α (β =  - 0.37; 95% CI, - 0.71 to - 0.02), and IFN-γ (β =  - 0.31; 95% CI, - 0.61 to - 0.03) in the placenta was negatively associated with preschoolers' full scale intelligence quotient (FSIQ). Both higher IL-8 and IL-6 were associated with lower children's low fluid reasoning index (FRI), and higher IFN-γ was associated with lower children's working memory index (WMI). After further adjusting for confounders and children's age at cognitive testing, the integrated index of six pro-inflammatory cytokines (index 2) was found to be significantly and negatively correlated with both the FSIQ and each sub-dimension (verbal comprehension index (VCI), visual spatial index (VSI), FRI, WMI, processing speed index (PSI)). Sex-stratified analyses showed that the association of IL-8, IFN-γ, and index 2 with children's cognitive development was mainly concentrated in boys.

CONCLUSIONS

Evidence of an association between low cognitive performance and high expression of placental inflammatory cytokines (IL-8, IL-6, TNF-α, and IFN-γ) was found, highlighting the potential importance of intrauterine placental immune status in dissecting offspring cognitive development.

Delineating early developmental pathways to ADHD: Setting an international research agenda

Background

Attention-deficit/hyperactivity disorder (ADHD) is a prevalent, impairing, and highly heritable condition typically diagnosed in middle childhood. However, it is now recognized that symptoms emerge much earlier in development. Research focused on understanding-using multiple units of analysis-the cascade of early-life (i.e., prenatal-infant-toddler) developmental changes that will later emerge as ADHD has the potential to transform early identification, prevention, and intervention. To this end, we introduce the recently established Early ADHD Consortium, an international network of investigators engaged in prospective, longitudinal studies of risk for ADHD beginning early in life, conducted within a developmental framework, and which incorporate multimethod approaches. This network seeks to harmonize measures and methodological approaches to increase the potential for data sharing and subsequent impact.

Methods

This perspective paper highlights the importance of investigating pre-diagnostic markers of ADHD, and potential models and mechanisms of ADHD risk and development, with the long-term objective of facilitating development of preemptive interventions that will minimize the impact of ADHD symptoms on everyday functioning and maximize health and developmental outcomes.

Results

We selectively describe key challenges and questions for this field related to theoretical models and developmental mechanisms in ADHD and recommend next steps for the science, including methodological, measurement, and study design considerations. We then describe potential implications for preemptive intervention development. We conclude by considering other issues including ethical concerns and the critical value of incorporating stakeholder input.

Conclusions

It is hoped that this perspective puts forth a research agenda that will enhance collaborative efforts and accelerate progress in understanding developmental mechanisms and the early ADHD phenotype, with implications for early intervention enhancement of healthy development for infants, young children, and their families.