Maternal Interleukin-6 concentration during pregnancy is associated with variation in frontolimbic white matter and cognitive development in early life

Examining longitudinal associations between prenatal exposure to infections and child brain morphology

BACKGROUND

Maternal infection during pregnancy has been identified as a prenatal risk factor for the later development of psychopathology in exposed offspring. Neuroimaging data collected during childhood has suggested a link between prenatal exposure to maternal infection and child brain structure and function, potentially offering a neurobiological explanation for the emergence of psychopathology. Additionally, preclinical studies utilizing repeated measures of neuroimaging data suggest that effects of prenatal maternal infection on the offspring's brain may normalize over time (i.e., catch-up growth). However, it remains unclear whether exposure to prenatal maternal infection in humans is related to long-term differential neurodevelopmental trajectories. Hence, this study aimed to investigate the association between prenatal exposure to infections on child brain development over time using repeated measures MRI data.

METHODS

We leveraged data from a population-based cohort, Generation R, in which we examined prospectively assessed self-reported infections at each trimester of pregnancy (N = 2,155). We further used three neuroimaging assessments (at mean ages 8, 10 and 14) to obtain cortical and subcortical measures of the offspring's brain morphology with MRI. Hereafter, we applied linear mixed-effects models, adjusting for several confounding factors, to estimate the association of prenatal maternal infection with child brain development over time.

RESULTS

We found that prenatal exposure to infection in the third trimester was associated with a slower decrease in volumes of the pars orbitalis, rostral anterior cingulate and superior frontal gyrus, and a faster increase in the middle temporal gyrus. In the temporal pole we observed a divergent pattern, specifically showing an increase in volume in offspring exposed to more infections compared to a decrease in volume in offspring exposed to fewer infections. We further observed associations in other frontal and temporal lobe structures after exposure to infections in any trimester, though these did not survive multiple testing correction.

CONCLUSIONS

Our results suggest that prenatal exposure to infections in the third trimester may be associated with slower age-related growth in the regions: pars orbitalis, rostral anterior cingulate and superior frontal gyrus, and faster age-related growth in the middle temporal gyrus across childhood, suggesting a potential sensitive period. Our results might be interpreted as an extension of longitudinal findings from preclinical studies, indicating that children exposed to prenatal infections could exhibit catch-up growth. However, given the lack of differences in brain volume between various infection groups at baseline, there may instead be either a longitudinal deviation or a subtle temporal deviation. Subsequent well-powered studies that extend into the period of full brain development (∼25 years) are needed to confirm whether the observed phenomenon is indeed catch-up growth, a longitudinal deviation, or a subtle temporal deviation.

Prenatal maternal Inflammation, childhood cognition and adolescent depressive symptoms

BACKGROUND

Accumulating evidence indicates that higher prenatal maternal inflammation is associated with increased depression risk in adolescent and adult-aged offspring. Prenatal maternal inflammation (PNMI) may increase the likelihood for offspring to have lower cognitive performance, which, in turn, may heighten risk for depression onset. Therefore, this study explored the potential mediating role of childhood cognitive performance in the relationship between PNMI and adolescent depressive symptoms in offspring.

METHODS

Participants included 696 mother-offspring dyads from the Child Health and Development Studies (CHDS) cohort. Biomarkers of maternal inflammation [interleukin (IL)-6, IL-8, IL-1 receptor antagonist (IL-1RA) and soluble TNF receptor-II (sTNF-RII)] were assayed from first (T1) and second trimester (T2) sera. Childhood (ages 9-11) cognitive performance was assessed via standardized Peabody Picture Vocabulary Test (PPVT), a measure of receptive vocabulary correlated with general intelligence. Adolescent (ages 15-17) depressive symptoms were assessed via self-report.

RESULTS

There were no significant associations between T1 biomarkers and childhood PPVT or adolescent depressive symptoms. Higher T2 IL1-RA was directly associated with lower childhood PPVT (b = -0.21, SE = 0.08, t = -2.55, p = 0.01), but not with adolescent depressive symptoms. T2 IL-6 was not directly associated with childhood PPVT, but higher T2 IL-6 was directly associated at borderline significance with greater depressive symptoms in adolescence (b = 0.05, SE = 0.03, t = 1.96, p = 0.05). Lower childhood PPVT predicted significantly higher adolescent depressive symptoms (b = -0.07, SE = 0.02, t = -2.99, p < 0.01). There was a significant indirect effect of T2 IL-1RA on adolescent depressive symptoms via childhood PPVT (b = 0.03, 95 % CI = 0.002-0.03) indicating a partially mediated effect. No significant associations were found with T2 sTNF-RII nor IL-8.

CONCLUSIONS

Lower childhood cognitive performance, such as that indicated by a lower PPVT score, represents a potential mechanism through which prenatal maternal inflammation contributes to adolescent depression risk in offspring.

Aflatoxin B1 exposure deteriorates immune abnormalities in a BTBR T+ Itpr3tf/J mouse model of autism by increasing inflammatory mediators' production in CD19-expressing cells

Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by deficiencies in communication, repetitive and stereotyped behavioral patterns, and difficulties in reciprocal social engagement. The presence of immunological dysfunction in ASD has been well established. Aflatoxin B1 (AFB1) is a prevalent mycotoxin found in food and feed, causing immune toxicity and hepatotoxicity. AFB1 is significantly elevated in several regions around the globe. Existing research indicates that prolonged exposure to AFB1 results in neurological problems. The BTBR T+ Itpr3tf/J (BTBR) mice, which were used as an autism model, exhibit the primary behavioral traits that define ASD, such as repeated, stereotyped behaviors and impaired social interactions. The main objective of this work was to assess the toxic impact of AFB1 in BTBR mice. This work aimed to examine the effects of AFB1 on the expression of Notch-1, IL-6, MCP-1, iNOS, GM-CSF, and NF-κB p65 by CD19+ B cells in the spleen of the BTBR using flow cytometry. We also verified the impact of AFB1 exposure on the mRNA expression levels of Notch-1, IL-6, MCP-1, iNOS, GM-CSF, and NF-κB p65 in the brain of BTBR mice using real-time PCR. The findings of our study showed that the mice treated with AFB1 in the BTBR group exhibited a substantial increase in the presence of CD19+Notch-1+, CD19+IL-6+, CD19+MCP-1+, CD19+iNOS+, CD19+GM-CSF+, and CD19+NF-κB p65+ compared to the mice in the BTBR group that were treated with saline. Our findings also confirmed that administering AFB1 to BTBR mice leads to elevated mRNA expression levels of Notch-1, IL-6, MCP-1, iNOS, GM-CSF, and NF-κB p65 in the brain, in comparison to BTBR mice treated with saline. The data highlight that exposure to AFB1 worsens immunological abnormalities by increasing the expression of inflammatory mediators in BTBR mice.

Advances in fetal and neonatal neuroimaging and everyday exposures

The complex, tightly regulated process of prenatal brain development may be adversely affected by "everyday exposures" such as stress and environmental pollutants. Researchers are only just beginning to understand the neural sequelae of such exposures, with advances in fetal and neonatal neuroimaging elucidating structural, microstructural, and functional correlates in the developing brain. This narrative review discusses the wide-ranging literature investigating the influence of parental stress on fetal and neonatal brain development as well as emerging literature assessing the impact of exposure to environmental toxicants such as lead and air pollution. These 'everyday exposures' can co-occur with other stressors such as social and financial deprivation, and therefore we include a brief discussion of neuroimaging studies assessing the effect of social disadvantage. Increased exposure to prenatal stressors is associated with alterations in the brain structure, microstructure and function, with some evidence these associations are moderated by factors such as infant sex. However, most studies examine only single exposures and the literature on the relationship between in utero exposure to pollutants and fetal or neonatal brain development is sparse. Large cohort studies are required that include evaluation of multiple co-occurring exposures in order to fully characterize their impact on early brain development. IMPACT: Increased prenatal exposure to parental stress and is associated with altered functional, macro and microstructural fetal and neonatal brain development. Exposure to air pollution and lead may also alter brain development in the fetal and neonatal period. Further research is needed to investigate the effect of multiple co-occurring exposures, including stress, environmental toxicants, and socioeconomic deprivation on early brain development.

Sex-Specific Pathways From Prenatal Maternal Inflammation to Adolescent Depressive Symptoms

Importance

Prenatal maternal inflammation has been associated with major depressive disorder in offspring in adulthood as well as with internalizing and externalizing symptoms in childhood; however, the association between prenatal inflammation and offspring depression in adolescence has yet to be examined.

Objective

To determine whether maternal levels of inflammatory biomarkers during pregnancy are associated with depressive symptomatology in adolescent-aged offspring and to examine how gestational timing, offspring sex, and childhood psychiatric symptoms impact these associations.

Design, Setting, and Participants

This was an observational study of a population-based birth cohort from the Child Health and Development Studies (CHDS), which recruited almost all mothers receiving obstetric care from the Kaiser Foundation Health Plan (KFHP) in Alameda County, California, between June 1959 and September 1966. Pregnancy data and blood sera were collected from mothers, and offspring psychiatric symptom data were collected in childhood (ages 9-11 years) and adolescence (ages 15-17 years). Mother-offspring dyads with available maternal prenatal inflammatory biomarkers during first and/or second trimesters and offspring depressive symptom data at adolescent follow-up were included. Data analyses took place between March 2020 and June 2023.

Exposures

Levels of inflammatory biomarkers (interleukin 6 [IL-6], IL-8, IL-1 receptor antagonist [IL-1RA], and soluble tumor necrosis factor receptor-II) assayed from maternal sera in the first and second trimesters of pregnancy.

Main Outcomes and Measures

Self-reported depressive symptoms at adolescent follow-up.

Results

A total of 674 mothers (mean [SD] age, 28.1 [5.9] years) and their offspring (350 male and 325 female) were included in this study. Higher second trimester IL-6 was significantly associated with greater depressive symptoms in offspring during adolescence (b, 0.57; SE, 0.26); P = .03). Moderated mediation analyses showed that childhood externalizing symptoms significantly mediated the association between first trimester IL-6 and adolescent depressive symptoms in male offspring (b, 0.18; 95% CI, 0.02-0.47), while childhood internalizing symptoms mediated the association between second trimester IL-1RA and adolescent depressive symptoms in female offspring (b, 0.80; 95% CI, 0.19-1.75).

Conclusions and Relevance

In this study, prenatal maternal inflammation was associated with depressive symptoms in adolescent-aged offspring. The findings of the study suggest that pathways to adolescent depressive symptomatology from prenatal risk factors may differ based on both the timing of exposure to prenatal inflammation and offspring sex.

Viral infections in pregnancy and impact on offspring neurodevelopment: mechanisms and lessons learned

Pregnant individuals with viral illness may experience significant morbidity and have higher rates of pregnancy and neonatal complications. With the growing number of viral infections and new viral pandemics, it is important to examine the effects of infection during pregnancy on both the gestational parent and the offspring. Febrile illness and inflammation during pregnancy are correlated with risk for autism, attention deficit/hyperactivity disorder, and developmental delay in the offspring in human and animal models. Historical viral epidemics had limited follow-up of the offspring of affected pregnancies. Infants exposed to seasonal influenza and the 2009 H1N1 influenza virus experienced increased risks of congenital malformations and neuropsychiatric conditions. Zika virus exposure in utero can lead to a spectrum of abnormalities, ranging from severe microcephaly to neurodevelopmental delays which may appear later in childhood and in the absence of Zika-related birth defects. Vertical infection with severe acute respiratory syndrome coronavirus-2 has occurred rarely, but there appears to be a risk for developmental delays in the infants with antenatal exposure. Determining how illness from infection during pregnancy and specific viral pathogens can affect pregnancy and neurodevelopmental outcomes of offspring can better prepare the community to care for these children as they grow. IMPACT: Viral infections have impacted pregnant people and their offspring throughout history. Antenatal exposure to maternal fever and inflammation may increase risk of developmental and neurobehavioral disorders in infants and children. The recent SARS-CoV-2 pandemic stresses the importance of longitudinal studies to follow pregnancies and offspring neurodevelopment.

Prenatal exposure to maternal disadvantage-related inflammatory biomarkers: associations with neonatal white matter microstructure

Prenatal exposure to heightened maternal inflammation has been associated with adverse neurodevelopmental outcomes, including atypical brain maturation and psychiatric illness. In mothers experiencing socioeconomic disadvantage, immune activation can be a product of the chronic stress inherent to such environmental hardship. While growing preclinical and clinical evidence has shown links between altered neonatal brain development and increased inflammatory states in utero, the potential mechanism by which socioeconomic disadvantage differentially impacts neural-immune crosstalk remains unclear. In the current study, we investigated associations between socioeconomic disadvantage, gestational inflammation, and neonatal white matter microstructure in 320 mother-infant dyads over-sampled for poverty. We analyzed maternal serum levels of four cytokines (IL-6, IL-8, IL-10, TNF-α) over the course of pregnancy in relation to offspring white matter microstructure and socioeconomic disadvantage. Higher average maternal IL-6 was associated with very low socioeconomic status (SES; INR < 200% poverty line) and lower neonatal corticospinal fractional anisotropy (FA) and lower uncinate axial diffusivity (AD). No other cytokine was associated with SES. Higher average maternal IL-10 was associated with lower FA and higher radial diffusivity (RD) in corpus callosum and corticospinal tracts, higher optic radiation RD, lower uncinate AD, and lower FA in inferior fronto-occipital fasciculus and anterior limb of internal capsule tracts. SES moderated the relationship between average maternal TNF-α levels during gestation and neonatal white matter diffusivity. When these interactions were decomposed, the patterns indicated that this association was significant and positive among very low SES neonates, whereby TNF-α was inversely and significantly associated with inferior cingulum AD. By contrast, among the more advantaged neonates (lower-to-higher SES [INR ≥ 200% poverty line]), TNF-α was positively and significantly associated with superior cingulum AD. Taken together, these findings suggest that the relationship between prenatal cytokine exposure and white matter microstructure differs as a function of SES. These patterns are consistent with a scenario where gestational inflammation's effects on white matter development diverge depending on the availability of foundational resources in utero.

Prenatal Programming of Monocyte Chemotactic Protein-1 Signaling in Autism Susceptibility

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder that involves functional and structural defects in selective central nervous system (CNS) regions, harming the individual capability to process and respond to external stimuli, including impaired verbal and non-verbal communications. Etiological causes of ASD have not been fully clarified; however, prenatal activation of the innate immune system by external stimuli might infiltrate peripheral immune cells into the fetal CNS and activate cytokine secretion by microglia and astrocytes. For instance, genomic and postmortem histological analysis has identified proinflammatory gene signatures, microglia-related expressed genes, and neuroinflammatory markers in the brain during ASD diagnosis. Active neuroinflammation might also occur during the developmental stage, promoting the establishment of a defective brain connectome and increasing susceptibility to ASD after birth. While still under investigation, we tested the hypothesis whether the monocyte chemoattractant protein-1 (MCP-1) signaling is prenatally programmed to favor peripheral immune cell infiltration and activate microglia into the fetal CNS, setting susceptibility to autism-like behavior. In this review, we will comprehensively provide the current understanding of the prenatal activation of MCP-1 signaling by external stimuli during the developmental stage as a new selective node to promote neuroinflammation, brain structural alterations, and behavioral defects associated to ASD diagnosis.

Local glycolysis fuels actomyosin contraction during axonal retraction

In response to repulsive cues, axonal growth cones can quickly retract. This requires the prompt activity of contractile actomyosin, which is formed by the non-muscle myosin II (NMII) bound to actin filaments. NMII is a molecular motor that provides the necessary mechanical force at the expense of ATP. Here, we report that this process is energetically coupled to glycolysis and is independent of cellular ATP levels. Induction of axonal retraction requires simultaneous generation of ATP by glycolysis, as shown by chemical inhibition and genetic knock-down of GAPDH. Co-immunoprecipitation and proximal-ligation assay showed that actomyosin associates with ATP-generating glycolytic enzymes and that this association is strongly enhanced during retraction. Using microfluidics, we confirmed that the energetic coupling between glycolysis and actomyosin necessary for axonal retraction is localized to the growth cone and near axonal shaft. These results indicate a tight coupling between on-demand energy production by glycolysis and energy consumption by actomyosin contraction suggesting a function of glycolysis in axonal guidance.

Human brain organoid model of maternal immune activation identifies radial glia cells as selectively vulnerable

Maternal immune activation (MIA) during critical windows of gestation is correlated with long-term neurodevelopmental deficits in the offspring, including increased risk for autism spectrum disorder (ASD) in humans. Interleukin 6 (IL-6) derived from the gestational parent is one of the major molecular mediators by which MIA alters the developing brain. In this study, we establish a human three-dimensional (3D) in vitro model of MIA by treating induced pluripotent stem cell-derived dorsal forebrain organoids with a constitutively active form of IL-6, Hyper-IL-6. We validate our model by showing that dorsal forebrain organoids express the molecular machinery necessary for responding to Hyper-IL-6 and activate STAT signaling upon Hyper-IL-6 treatment. RNA sequencing analysis reveals the upregulation of major histocompatibility complex class I (MHCI) genes in response to Hyper-IL-6 exposure, which have been implicated with ASD. We find a small increase in the proportion of radial glia cells after Hyper-IL-6 treatment through immunohistochemistry and single-cell RNA-sequencing. We further show that radial glia cells are the cell type with the highest number of differentially expressed genes, and Hyper-IL-6 treatment leads to the downregulation of genes related to protein translation in line with a mouse model of MIA. Additionally, we identify differentially expressed genes not found in mouse models of MIA, which might drive species-specific responses to MIA. Finally, we show abnormal cortical layering as a long-term consequence of Hyper-IL-6 treatment. In summary, we establish a human 3D model of MIA, which can be used to study the cellular and molecular mechanisms underlying the increased risk for developing disorders such as ASD.

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.

Disruption of Intranasal GnRH Neuronal Migration Route into the Brain Induced by Proinflammatory Cytokine IL-6: Ex Vivo and In Vivo Rodent Models

Maternal immune activation results in altered levels of cytokines in the maternal-fetal system, which has a negative impact on fetal development, including the gonadotropin-releasing hormone (GnRH) system, which is crucial for the reproduction. Suppression of GnRH-neuron migration may be associated with cytokine imbalances, and primarily with proinflammatory cytokine interleukin (IL)-6. This study aimed to determine the effects of IL-6 and monoclonal antibody to IL-6 or IL-6R or polyclonal IgG on the formation of migration route of GnRH-neurons in ex vivo and in vivo rodent models on day 11.5 of embryonic development. The increased level of IL-6 in mouse nasal explants suppressed peripherin-positive fiber outgrowth, while this led to an increase in the number of GnRH-neurons in the nose and olfactory bulbs and a decrease in their number in the fetal brain. This effect is likely to be realized via IL-6 receptors along the olfactory nerves. The suppressive effect of IL-6 was diminished by monoclonal antibodies to IL-6 or its receptors and by IgG.

Long-term effects of prenatal infection on the human brain: a prospective multimodal neuroimaging study

There is convincing evidence from rodent studies suggesting that prenatal infections affect the offspring's brain, but evidence in humans is limited. Here, we assessed the occurrence of common infections during each trimester of pregnancy and examined associations with brain outcomes in adolescent offspring. Our study was embedded in the Generation R Study, a large-scale sociodemographically diverse prospective birth cohort. We included 1094 mother-child dyads and investigated brain morphology (structural MRI), white matter microstructure (DTI), and functional connectivity (functional MRI), as outcomes at the age of 14. We focused on both global and focal regions. To define prenatal infections, we composed a score based on the number and type of infections during each trimester of pregnancy. Models were adjusted for several confounders. We found that prenatal infection was negatively associated with cerebral white matter volume (B = -0.069, 95% CI -0.123 to -0.015, p = 0.011), and we found an association between higher prenatal infection scores and smaller volumes of several frontotemporal regions of the brain. After multiple testing correction, we only observed an association between prenatal infections and the caudal anterior cingulate volume (B = -0.104, 95% CI -0.164 to -0.045, p < 0.001). We did not observe effects of prenatal infection on other measures of adolescent brain morphology, white matter microstructure, or functional connectivity, which is reassuring. Our results show potential regions of interest in the brain for future studies; data on the effect of severe prenatal infections on the offspring's brain in humans are needed.

Beyond TORCH: A narrative review of the impact of antenatal and perinatal infections on the risk of disability

Infections and inflammation during pregnancy or early life can alter child neurodevelopment and increase the risk for structural brain abnormalities and mental health disorders. There is strong evidence that TORCH infections (i.e., Treponema pallidum, Toxoplasma gondii, rubella virus, cytomegalovirus, herpes virus) alter fetal neurodevelopment across multiple developmental domains and contribute to motor and cognitive disabilities. However, the impact of a broader range of viral and bacterial infections on fetal development and disability is less well understood. We performed a literature review of human studies to identify gaps in the link between maternal infections, inflammation, and several neurodevelopmental domains. We found strong and moderate evidence respectively for a higher risk of motor and cognitive delays and disabilities in offspring exposed to a range of non-TORCH pathogens during fetal life. In contrast, there is little evidence for an increased risk of language and sensory disabilities. While guidelines for TORCH infection prevention during pregnancy are common, further consideration for prevention of non-TORCH infections during pregnancy for fetal neuroprotection may be warranted.

Gestational and postnatal age associations for striatal tissue iron deposition in early infancy

Striatal development is crucial for later motor, cognitive, and reward behavior, but age-related change in striatal physiology during the neonatal period remains understudied. An MRI-based measure of tissue iron deposition, T2*, is a non-invasive way to probe striatal physiology neonatally, linked to dopaminergic processing and cognition in children and adults. Striatal subregions have distinct functions that may come online at different time periods in early life. To identify if there are critical periods before or after birth, we measured if striatal iron accrued with gestational age at birth [range= 34.57-41.85 weeks] or postnatal age at scan [range= 5-64 days], using MRI to probe the T2* signal in N = 83 neonates in three striatal subregions. We found iron increased with postnatal age in the pallidum and putamen but not the caudate. No significant relationship between iron and gestational age was observed. Using a subset of infants scanned at preschool age (N = 26), we show distributions of iron shift between time points. In infants, the pallidum had the least iron of the three regions but had the most by preschool age. Together, this provides evidence of distinct change for striatal subregions, a possible differentiation between motor and cognitive systems, identifying a mechanism that may impact future trajectories.

Extracellular free water elevations are associated with brain volume and maternal cytokine response in a longitudinal nonhuman primate maternal immune activation model

Maternal infection has emerged as an important environmental risk factor for neurodevelopmental disorders, including schizophrenia and autism spectrum disorders. Animal model systems of maternal immune activation (MIA) suggest that the maternal immune response plays a significant role in the offspring's neurodevelopment and behavioral outcomes. Extracellular free water is a measure of freely diffusing water in the brain that may be associated with neuroinflammation and impacted by MIA. The present study evaluates the brain diffusion characteristics of male rhesus monkeys (Macaca mulatta) born to MIA-exposed dams (n = 14) treated with a modified form of the viral mimic polyinosinic:polycytidylic acid at the end of the first trimester. Control dams received saline injections at the end of the first trimester (n = 10) or were untreated (n = 4). Offspring underwent diffusion MRI scans at 6, 12, 24, 36, and 45 months. Offspring born to MIA-exposed dams showed significantly increased extracellular free water in cingulate cortex gray matter starting as early as 6 months of age and persisting through 45 months. In addition, offspring gray matter free water in this region was significantly correlated with the magnitude of the maternal IL-6 response in the MIA-exposed dams. Significant correlations between brain volume and extracellular free water in the MIA-exposed offspring also indicate converging, multimodal evidence of the impact of MIA on brain development. These findings provide strong evidence for the construct validity of the nonhuman primate MIA model as a system of relevance for investigating the pathophysiology of human neurodevelopmental psychiatric disorders. Elevated free water in individuals exposed to immune activation in utero could represent an early marker of a perturbed or vulnerable neurodevelopmental trajectory.

Fetal Frontolimbic Connectivity Prospectively Associates With Aggression in Toddlers

Background

Aggression is a major public health concern that emerges early in development and lacks optimized treatment, highlighting need for improved mechanistic understanding regarding the etiology of aggression. The present study leveraged fetal resting-state functional magnetic resonance imaging to identify candidate neurocircuitry for the onset of aggressive behaviors before symptom emergence.

Methods

Pregnant mothers were recruited during the third trimester of pregnancy to complete a fetal resting-state functional magnetic resonance imaging scan. Mothers subsequently completed the Child Behavior Checklist to assess child aggression at 3 years postpartum (n = 79). Independent component analysis was used to define frontal and limbic regions of interest.

Results

Child aggression was not related to within-network connectivity of subcortical limbic regions or within-medial prefrontal network connectivity in fetuses. However, weaker functional coupling between the subcortical limbic network and medial prefrontal network in fetuses was prospectively associated with greater maternal-rated child aggression at 3 years of age even after controlling for maternal emotion dysregulation and toddler language ability. We observed similar, but weaker, associations between fetal frontolimbic functional connectivity and toddler internalizing symptoms.

Conclusions

Neural correlates of aggressive behavior may be detectable in utero, well before the onset of aggression symptoms. These preliminary results highlight frontolimbic connections as potential candidate neurocircuitry that should be further investigated in relation to the unfolding of child behavior and psychiatric risk.

Effects of physical activity in child and adolescent depression and anxiety: role of inflammatory cytokines and stress-related peptide hormones

Depression and anxiety are the most common mental illnesses affecting children and adolescents, significantly harming their well-being. Research has shown that regular physical activity can promote cognitive, emotional, fundamental movement skills, and motor coordination, as a preventative measure for depression while reducing the suicide rate. However, little is known about the potential role of physical activity in adolescent depression and anxiety. The studies reviewed in this paper suggest that exercise can be an effective adjunctive treatment to improve depressive and anxiety symptoms in adolescents, although research on its neurobiological effects remains limited.

Maternal prenatal immune activation associated with brain tissue microstructure and metabolite concentrations in newborn infants

Importance

Few translational human studies have assessed the association of prenatal maternal immune activation with altered brain development and psychiatric risk in newborn offspring.

Objective

To identify the effects of maternal immune activation during the 2nd and 3rd trimesters of pregnancy on newborn brain metabolite concentrations, tissue microstructure, and longitudinal motor development.

Design

Prospective longitudinal cohort study conducted from 2012 - 2017.

Setting

Columbia University Irving Medical Center and Weill Cornell Medical College.

Participants

76 nulliparous pregnant women, aged 14 to 19 years, were recruited in their 2nd trimester, and their children were followed through 14 months of age.

Exposure

Maternal immune activation indexed by maternal interleukin-6 and C-reactive protein in the 2nd and 3rd trimesters of pregnancy.

Main Outcomes and Measures

The main outcomes included (1) newborn metabolite concentrations, measured as N-acetylaspartate, creatine, and choline using Magnetic Resonance Spectroscopy; (2) newborn fractional anisotropy and mean diffusivity measured using Diffusion Tensor Imaging; and (3) indices of motor development assessed prenatally and postnatally at ages 4- and 14-months.

Results

Maternal interleukin-6 and C-reactive protein levels in the 2nd or 3rd trimester were significantly positively associated with the N-acetylaspartate, creatine, and choline concentrations in the putamen, thalamus, insula, and anterior limb of the internal capsule. Maternal interleukin-6 was associated with fractional anisotropy in the putamen, insula, thalamus, precuneus, and caudate, and with mean diffusivity in the inferior parietal and middle temporal gyrus. C-reactive protein was associated with fractional anisotropy in the thalamus, insula, and putamen. Regional commonalities were found across imaging modalities, though the direction of the associations differed by immune marker. In addition, a significant positive association was observed between offspring motor development and both maternal interleukin-6 and C-reactive protein (in both trimesters) prenatally and 4- and 14-months of age.

Conclusions and Relevance

Using a healthy sample, these findings demonstrate that levels of maternal immune activation in mid- to late pregnancy associate with tissue characteristics in newborn brain regions primarily supporting motor integration/coordination and behavioral regulation and may lead to alterations in motor development.

Gestational and postnatal age associations for striatal tissue iron deposition in early infancy

Striatal development is crucial for later motor, cognitive, and reward behavior, but age-related change in striatal physiology during the neonatal period remains understudied. An MRI-based measure of tissue iron deposition, T2*, is a non-invasive way to probe striatal physiology neonatally, linked to dopaminergic processing and cognition in children and adults. Striatal subregions have distinct functions that may come online at different time periods in early life. To identify if there are critical periods before or after birth, we measured if striatal iron accrued with gestational age at birth [range=34.57-41.85 weeks] or postnatal age at scan [range=5-64 days], using MRI to probe the T2* signal in N=83 neonates in three striatal subregions. We found iron increased with postnatal age in the pallidum and putamen but not the caudate. No significant relationship between iron and gestational age was observed. Using a subset of infants scanned at preschool age (N=26), we show distributions of iron shift between timepoints. In infants, the pallidum had the least iron of the three regions but had the most by preschool age. Together, this provides evidence of distinct change for striatal subregions, a possible differentiation between motor and cognitive systems, identifying a mechanism that may impact future trajectories.

Highlights

Neonatal striatal tissue iron can be measured using the T2* signal from rsfMRInT2* changed with postnatal age in the pallidum and putamen but not in the caudatenT2* did not change with gestational age in any of the three regionsPatterns of iron deposition (nT2*) among regions shift from infancy to preschool.

Fetal inflammatory response and risk for psychiatric disorders

Inflammation contributes to numerous neuropsychiatric disorders, especially those that first appear in childhood. Maternal intrauterine environment, including the placenta, has a role in brain development and risk for neuropsychiatric disorders. This study examines the link between fetal inflammatory syndrome (FIRS), which is placental inflammation in the peri-partem period, and neuropsychiatric disorders during childhood.This is a retrospective cohort study using data from electronic medical records over a 19-year period at one women's hospital. The study includes 4851 children born with placentas meeting criteria for and 31,927 controls identified with normal placentas born during the same period. To be diagnosed with FIRS placenta must contain chorionic vasculitis and/or funisitis. Children had to be in study period for at least 5 years. The primary outcome of the study is incidence of neuropsychiatric disorders during childhood. The secondary outcomes were psychiatric medications prescribed, and psychiatric hospitalizations and treatment. Children born to placentas meeting criteria for FIRS were more likely to be diagnosed with neuropsychiatric disorders (OR = 1.21, CI 95% [1.09,1.35]). Specifically, they were more likely to be diagnosed with autism spectrum disorder (OR = 1.35, CI 95% [1.08, 1.67]), ADHD (OR = 1.27, CI 95% [1.07, 1.49]), conduct disorder (OR = 1.50, CI 95% [1.24, 1.81]), PTSD (OR = 2.46. CI 95% [1.21, 5.04]), adjusting for maternal history of psychiatric disorders, intra-partem substance use, and prescriptions of anti-inflammatory drugs. Children born with placental inflammation are at an increased risk to develop neuropsychiatric disorders. This has profound implications for future research, and early detection, monitoring, and treatment in these children.

Acute IL-6 exposure triggers canonical IL6Ra signaling in hiPSC microglia, but not neural progenitor cells

BACKGROUND

Prenatal exposure to elevated interleukin (IL)-6 levels is associated with increased risk for psychiatric disorders with a putative neurodevelopmental origin, such as schizophrenia (SZ), autism spectrum condition (ASC) and bipolar disorder (BD). Although rodent models provide causal evidence for this association, we lack a detailed understanding of the cellular and molecular mechanisms in human model systems. To close this gap, we characterized the response of human induced pluripotent stem cell (hiPSC-)derived microglia-like cells (MGL) and neural progenitor cells (NPCs) to IL-6 in monoculture.

RESULTS

We observed that human forebrain NPCs did not respond to acute IL-6 exposure in monoculture at both protein and transcript levels due to the absence of IL6R expression and soluble (s)IL6Ra secretion. By contrast, acute IL-6 exposure resulted in STAT3 phosphorylation and increased IL6, JMJD3 and IL10 expression in MGL, confirming activation of canonical IL6Ra signaling. Bulk RNAseq identified 156 up-regulated genes (FDR < 0.05) in MGL following acute IL-6 exposure, including IRF8, REL, HSPA1A/B and OXTR, which significantly overlapped with an up-regulated gene set from human post-mortem brain tissue from individuals with schizophrenia. Acute IL-6 stimulation significantly increased MGL motility, consistent with gene ontology pathways highlighted from the RNAseq data and replicating rodent model indications that IRF8 regulates microglial motility. Finally, IL-6 induces MGLs to secrete CCL1, CXCL1, MIP-1α/β, IL-8, IL-13, IL-16, IL-18, MIF and Serpin-E1 after 3 h and 24 h.

CONCLUSION

Our data provide evidence for cell specific effects of acute IL-6 exposure in a human model system, ultimately suggesting that microglia-NPC co-culture models are required to study how IL-6 influences human cortical neural progenitor cell development in vitro.

Intra-amniotic inflammation in the mid-trimester of pregnancy is a risk factor for neuropsychological disorders in childhood

OBJECTIVES

Intra-amniotic inflammation is a subclinical condition frequently caused by either microbial invasion of the amniotic cavity or sterile inflammatory stimuli, e.g., alarmins. An accumulating body of evidence supports a role for maternal immune activation in the genesis of fetal neuroinflammation and the occurrence of neurodevelopmental disorders such as cerebral palsy, schizophrenia, and autism. The objective of this study was to determine whether fetal exposure to mid-trimester intra-amniotic inflammation is associated with neurodevelopmental disorders in children eight to 12 years of age.

METHODS

This is a retrospective case-control study comprising 20 children with evidence of prenatal exposure to intra-amniotic inflammation in the mid-trimester and 20 controls matched for gestational age at amniocentesis and at delivery. Amniotic fluid samples were tested for concentrations of interleukin-6 and C-X-C motif chemokine ligand 10, for bacteria by culture and molecular microbiologic methods as well as by polymerase chain reaction for eight viruses. Neuropsychological testing of children, performed by two experienced psychologists, assessed cognitive and behavioral domains. Neuropsychological dysfunction was defined as the presence of an abnormal score (<2 standard deviations) on at least two cognitive tasks.

RESULTS

Neuropsychological dysfunction was present in 45% (9/20) of children exposed to intra-amniotic inflammation but in only 10% (2/20) of those in the control group (p=0.03). The relative risk (RR) of neuropsychological dysfunction conferred by amniotic fluid inflammation remained significant after adjusting for gestational age at delivery [aRR=4.5 (1.07-16.7)]. Of the 11 children diagnosed with neuropsychological dysfunction, nine were delivered at term and eight of them had mothers with intra-amniotic inflammation. Children exposed to intra-amniotic inflammation were found to have abnormalities in neuropsychological tasks evaluating complex skills, e.g., auditory attention, executive functions, and social skills, whereas the domains of reasoning, language, and memory were not affected in the cases and controls.

CONCLUSIONS

Asymptomatic sterile intra-amniotic inflammation in the mid-trimester of pregnancy, followed by a term birth, can still confer to the offspring a substantial risk for neurodevelopmental disorders in childhood. Early recognition and treatment of maternal immune activation in pregnancy may be a strategy for the prevention of subsequent neurodevelopmental disorders in offspring.

Altered dendritic morphology in dorsolateral prefrontal cortex of nonhuman primates prenatally exposed to maternal immune activation

Women who contract a viral or bacterial infection during pregnancy have an increased risk of giving birth to a child with a neurodevelopmental or psychiatric disorder. The effects of maternal infection are likely mediated by the maternal immune response, as preclinical animal models have confirmed that maternal immune activation (MIA) leads to long lasting changes in offspring brain and behavior development. The present study sought to determine the impact of MIA-exposure during the first or second trimester on neuronal morphology in dorsolateral prefrontal cortex (DLPFC) and hippocampus from brain tissue obtained from MIA-exposed and control male rhesus monkey (Macaca mulatta) during late adolescence. MIA-exposed offspring display increased neuronal dendritic branching in pyramidal cells in DLPFC infra- and supragranular layers relative to controls, with no significant differences observed between offspring exposed to maternal infection in the first and second trimester. In addition, the diameter of apical dendrites in DLPFC infragranular layer is significantly decreased in MIA-exposed offspring relative to controls, irrespective of trimester exposure. In contrast, alterations in hippocampal neuronal morphology of MIA-exposed offspring were not evident. These findings demonstrate that a maternal immune challenge during pregnancy has long-term consequences for primate offspring dendritic structure, selectively in a brain region vital for socioemotional and cognitive development.

Associations between the human immune system and gut microbiome with neurodevelopment in the first 5 years of life: A systematic scoping review

The aim of this review was to map the literature assessing associations between maternal or infant immune or gut microbiome biomarkers and child neurodevelopmental outcomes within the first 5 years of life. We conducted a PRISMA-ScR compliant review of peer-reviewed, English-language journal articles. Studies reporting gut microbiome or immune system biomarkers and child neurodevelopmental outcomes prior to 5 years were eligible. Sixty-nine of 23,495 retrieved studies were included. Of these, 18 reported on the maternal immune system, 40 on the infant immune system, and 13 on the infant gut microbiome. No studies examined the maternal microbiome, and only one study examined biomarkers from both the immune system and the gut microbiome. Additionally, only one study included both maternal and infant biomarkers. Neurodevelopmental outcomes were assessed from 6 days to 5 years. Associations between biomarkers and neurodevelopmental outcomes were largely nonsignificant and small in effect size. While the immune system and gut microbiome are thought to have interactive impacts on the developing brain, there remains a paucity of published studies that report biomarkers from both systems and associations with child development outcomes. Heterogeneity of research designs and methodologies may also contribute to inconsistent findings. Future studies should integrate data across biological systems to generate novel insights into the biological underpinnings of early development.

Maternal early life stress is associated with pro-inflammatory processes during pregnancy

Early life stress (ELS) is common in the United States and worldwide, and contributes to the development of psychopathology in individuals with these experiences and their offspring. A growing body of research suggests that early life stress may contribute to adverse health partly through modulation of immune (and particularly inflammatory) responses. Therefore, increased maternal prenatal inflammation has been proposed as a mechanistic pathway by which the observed cross-generational effects of parental early life stress on child neuropsychiatric outcomes may be exerted. We examined associations between early life stress and molecular markers of inflammation (specifically pro-inflammatory gene expression and receptor-mediated transcription factor activity) and a commonly studied circulating marker of inflammation (C-Reactive Protein) in a diverse group of women in or near their third trimester of pregnancy, covarying for age, race/ethnicity, BMI, concurrent infection, concurrent perceived stress, and per capita household income. Mothers who experienced higher levels of early life stress had significantly increased pro-inflammatory (NF-κB) and decreased anti-viral (IRF) transcription factor activity. Transcripts that were up or down regulated in mothers with high ELS were preferentially derived from both CD16+ and CD16- monocytes. Early life stress was not associated with elevated CRP. Taken together, these findings provide preliminary evidence for an association between ELS and a pro-inflammatory transcriptional phenotype during pregnancy that may serve as a mechanistic pathway for cross-generational transmission of the effects of early life stress on mental and physical health.

Maternal pre-pregnancy body mass index is associated with newborn offspring hypothalamic mean diffusivity: a prospective dual-cohort study

BACKGROUND

An extensive body of animal literature supports the premise that maternal obesity during pregnancy can alter the development of the fetal hypothalamus (HTH, a critical regulator of energy balance) with implications for offspring obesity risk (i.e., long-term energy imbalance). Yet, the relationship in humans between maternal overweight/obesity during pregnancy and fetal hypothalamic development remains largely unknown. Here, using an international (Finland and California, USA) multi-site diffusion tensor imaging (DTI) dataset, we test the hypothesis that maternal pre-pregnancy BMI is associated with newborn offspring HTH mean diffusivity (HTH MD, a replicable neural correlate of BMI in adults).

METHODS

HTH MD was independently quantified in two separate BMI-matched cohorts (up to class II obesity; BMIRange = 17-35) using a high-resolution atlas-based definition of HTH. A total of n = 231 mother-child dyads were available for this analysis (nSite,1 = 152, age at MRI = 26.7 ± 8.1 days, gestational age at birth = 39.9 ± 1.2 weeks, nM/F = 82/70, BMI = 24.2 ± 3.8; nSite,2 = 79, age at MRI = 25.6 ± 12.5 days, gestational age at birth = 39.3 ± 1.5 weeks, nM/F = 45/34, BMI = 25.1 ± 4.0). The association between maternal pre-pregnancy BMI and newborn offspring HTH MD was examined separately in each cohort using linear regression adjusting for gestational age at birth, postnatal age at scan, sex, whole white matter mean diffusivity, and DTI quality control criteria. In post hoc analyses, additional potentially confounding factors including socioeconomic status, ethnicity, and obstetric risk were adjusted where appropriate.

RESULTS

The distribution of maternal pre-pregnancy BMI was comparable across sites but differed by ethnicity and socioeconomic status. A positive linear association between maternal pre-pregnancy BMI and newborn offspring HTH MD was observed at both sites ([Formula: see text]Site,1 = 0.17, pSite,1 = 0.01; [Formula: see text]Site,2 = 0.22, pSite,2 = 0.03) and remained significant after adjusting for cohort-relevant covariates.

CONCLUSIONS

These findings translate the preclinically established association between maternal obesity during pregnancy and offspring hypothalamic microstructure to the human context. In addition to further replication/generalization, future efforts to identify biological mediators of the association between maternal obesity and fetal HTH development are warranted to develop targeted strategies for the primary prevention of childhood obesity.

Risk of attention deficit hyperactivity and autism spectrum disorders among the children of parents with autoimmune diseases: a nationwide birth cohort study

Studies have suggested that maternal autoimmune diseases are associated with an increased risk of attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). However, research on the association of paternal autoimmune diseases with ADHD and ASD risk has remained inconclusive. Using the Taiwan National Health Insurance Research Database, we selected 708,517 family triads (father-mother-child) between 2001 and 2008 and followed them until the end of 2011. Parental autoimmune diseases as well as ADHD and ASD in children were identified during the study period. Increased ADHD risk in children in terms of hazard ratios (HRs) and 95% confidence intervals (CIs) was associated with prenatal exposure to paternal autoimmune diseases, including Sjögren's syndrome (HR: 8.41, 95% CI: 2.72-26.05), psoriasis (HR: 1.95, 95% CI: 1.05-3.63), and ankylosing spondylitis (HR: 2.02, 95% CI: 1.29-2.15), as well as maternal autoimmune diseases, such as systemic lupus erythematosus (HR: 1.53, 95% CI: 1.09-2.15), type 1 diabetes mellitus (HR: 1.55, 95% CI: 1.02-2.36), inflammatory bowel disease (HR: 2.37, 95% CI: 1.59-3.52), psoriasis (HR: 1.70, 95% CI: 1.00-2.87), and ankylosing spondylitis (HR: 2.07, 95% CI: 1.11-3.86). However, ASD was only associated with paternal inflammatory bowel disease (HR: 3.08, 95% CI: 1.15-8.28) and ankylosing spondylitis (HR: 2.65, 95% CI: 1.10-6.39). Both paternal and maternal autoimmune diseases were associated with increased likelihood of ADHD in children. However, only paternal autoimmune diseases were related to offspring ASD risk. The precise pathomechanism underlying the correlation between parental autoimmunity and child neurodevelopment requires further investigation.

Maternal pre-eclampsia serum increases neurite growth and mitochondrial function through a potential IL-6-dependent mechanism in differentiated SH-SY5Y cells

Introduction: Pre-eclampsia (PE) is a common and serious hypertensive disorder of pregnancy, which affects 3%-5% of first-time pregnancies and is a leading cause of maternal and neonatal morbidity and mortality. Prenatal exposure to PE is associated with an increased risk of neurodevelopmental disorders in affected offspring, although the cellular and molecular basis of this increased risk is largely unknown. Methods: Here, we examined the effects of exposure to maternal serum from women with PE or a healthy uncomplicated pregnancy on the survival, neurite growth and mitochondrial function of neuronally differentiated human SH-SY5Y neuroblastoma cells, which are commonly used to study neurite growth. Neurite growth and mitochondrial function are two strongly linked neurodevelopmental parameters in which alterations have been implicated in neurodevelopmental disorders. Following this, we investigated the pleiotropic cytokine interleukin-6 (IL-6) levels as a potential mechanism. Results: Cells exposed to 3% (v/v) PE serum for 72 h exhibited increased neurite growth (p < 0.05), which was validated in the human neural progenitor cell line, ReNcell^® VM (p < 0.01), and mitochondrial respiration (elevated oxygen consumption rate (p < 0.05), basal mitochondrial respiration, proton leak, ATP synthesis, and non-mitochondrial respiration) compared to control serum-treated cells. ELISA analysis showed elevations in maternal IL-6 in PE sera (p < 0.05) and placental explants (p < 0.05). In support of this, SH-SY5Y cells exposed to 3% (v/v) PE serum for 24 h had increased phospho-STAT3 levels, which is a key intracellular mediator of IL-6 signalling (p < 0.05). Furthermore, treatment with anti-IL-6 neutralizing antibody blocked the effects of PE serum on neurite growth (p < 0.05), and exposure to IL-6 promoted neurite growth in SH-SY5Y cells (p < 0.01). Discussion: Collectively these data show elevated serum levels of maternal IL-6 in PE, which increases neurite growth and mitochondrial function in SH-SY5Y cells. This rationalizes the further study of IL-6 as a potential mediator between PE exposure and neurodevelopmental outcome in the offspring.

Associations of cord blood meta-inflammation and vitamin D with neurodevelopmental delay: A prospective birth cohort study in China

Aim

To estimate the associations of cord meta-inflammatory markers with neurodevelopment, including the potential impact of cord blood vitamin D levels.

Method

The prospective cohort study comprised 7198 participants based on the Maternal & Infants Health in Hefei study. Cord blood C-peptide, high-sensitive C-reactive protein (hsCRP), high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol, total cholesterol, triglycerides and 25(OH)D levels were measured. The Gesell Developmental Schedules were used to assess neurodevelopmental outcomes in offspring.

Results

After adjusting potential confounders, per quartile increase in cord blood 25(OH)D concentrations was associated with a decreased risk of neurodevelopmental delay [hazard ratios (HR) 0.65 (95% CI 0.57, 0.74)]. Conversely, significant positive associations with cord blood serum C-peptide levels above the 90th percentile [HR 2.38 (95% CI 1.81, 3.13)] and higher levels of cord hsCRP (per quartile increase) [HR 1.18 (95% CI 1.01, 1.37)] with neurodevelopmental delay were observed. These associations could vary by quartiles of cord blood 25(OH)D levels: the adjusted HRs in neurodevelopmental delay comparing children with vs without hyperinsulinemia were 1.28 (95% CI: 1.03, 1.59) for quartiles 1 (lowest), and 1.06 (95% CI: 0.78, 1.44) for quartile 4 (highest).

Conclusions

Immune activation and metabolic abnormalities in fetal circulation were associated with neurodevelopmental delay in offspring, which could be attenuated by higher cord blood 25(OH)D levels in a dose-response manner.

Pregnancy during the pandemic: the impact of COVID-19-related stress on risk for prenatal depression

BACKGROUND

Pregnant women may be especially susceptible to negative events (i.e. adversity) related to the coronavirus disease 2019 (COVID-19) pandemic and negative affective responses to these events (i.e. stress). We examined the latent structure of stress and adversity related to the COVID-19 pandemic among pregnant women, potential antecedents of COVID-19-related stress and adversity in this population, and associations with prenatal depressive symptoms.

METHOD

We surveyed 725 pregnant women residing in the San Francisco Bay Area in March-May 2020, 343 of whom provided addresses that were geocoded and matched by census tract to measures of community-level risk. We compared their self-reported depressive symptoms to women matched on demographic factors and history of mental health difficulties who were pregnant prior to the pandemic.

RESULTS

Women who were pregnant during the pandemic were nearly twice as likely to have possible depression than were matched women who were pregnant prior to the pandemic. Individual- and community-level factors tied to socioeconomic inequality were associated with latent factors of COVID-19-related stress and adversity. Beyond objective adversity, subjective stress responses were strongly associated with depressive symptoms during the pandemic.

CONCLUSIONS

Highlighting the role of subjective responses in vulnerability to prenatal depression and factors that influence susceptibility to COVID-19-related stress, these findings inform the allocation of resources to support recovery from this pandemic and future disease outbreaks. In addition to policies that mitigate disruptions to the environment due to the pandemic, treatments that focus on cognitions about the self and the environment may help to alleviate depressive symptoms in pregnant women.

Maternal anxiety, depression and stress affects offspring gut microbiome diversity and bifidobacterial abundances

Uncovering mechanisms underlying fetal programming during pregnancy is of critical importance. Atypical neurodevelopment during the pre- and immediate postnatal period has been associated with long-term adverse health outcomes, including mood disorders and aberrant cognitive ability in offspring. Maternal factors that have been implicated in anomalous offspring development include maternal inflammation and tress, anxiety, and depression. One potential mechanism through which these factors perturb normal offspring postnatal development is through microbiome disruption. The mother is a primary source of early postnatal microbiome seeding for the offspring, and the transference of a healthy microbiome is key in normal neurodevelopment. Since psychological stress, mood disorders, and inflammation have all been implicated in altering maternal microbiome community structure, passing on aberrant microbial communities to the offspring that may then affect developmental outcomes. Therefore, we examined how maternal stress, anxiety and depression assessed with standardized instruments, and maternal inflammatory cytokine levels in the pre- and postnatal period are associated with the offspring microbiome within the first 13 months of life, utilizing full length 16S sequencing on infant stool samples, that allowed for species-level resolution. Results revealed that infants of mothers who reported higher anxiety and perceived stress had reduced alpha diversity. Additionally, the relative taxonomic quantitative abundances of Bifidobacterium dentium and other species that have been associated with either modulation of the gut-brain axis, or other beneficial health outcomes, were reduced in the offspring of mothers with higher anxiety, perceived stress, and depression. We also found associations between bifidobacteria and prenatal maternal pro-inflammatory cytokines IL-6, IL-8, and IL-10. In summary, specific microbial taxa involved in maintaining proper brain and immune function are lower in offspring born to mothers with anxiety, depression, or stress, providing strong evidence for a mechanism by which maternal factors may affect offspring health through microbiota dysregulation.

AUTISM SPECTRUM DISORDER AND SCHIZOPHRENIA - SIMILARITIES BETWEEN THE TWO DISORDERS WITH A CASE REPORT OF A PATIENT WITH DUAL DIAGNOSIS

This paper presents the genetic, molecular and neuroanatomical similarities between autism spectrum disorder (ASD) and schizophrenia using the case report of a 34-year-old female patient with a previous diagnosis of schizophrenia as an example. As a result of repeat hospitalization, expanded history, psychological testing and verification of persistent symptoms of psychopathology, a cooccurring diagnosis of autism spectrum disorder was made.

Racial differences in the associations between adiposity, placental growth hormone and inflammatory cytokines in pregnant women

BACKGROUND

The prevalence of obesity among women of child-bearing age has contributed to an increased risk of pregnancy complications with a disproportional impact on women of lower socioeconomic status and among certain racial groups. In particular, socio-demographic and historical factors have resulted in higher rates of premature births and small-for-gestational age infants among Black women, which may be associated with placental function during pregnancy. The current study investigated the influence of maternal pre-pregnancy adiposity and race on the associations between inflammatory proteins, placental growth hormone (PGH), and infant birthweight. This information was collected for a subsample of 109 participants (Black, n = 39 vs. White, n = 70) from the Brain and Early Experiences (BEE) study.

METHODS

Serum samples were acquired late in the second trimester to assess PGH levels, C-reactive protein (CRP), interleukin 6 (IL-6), interleukin 8 (IL-8), and interleukin-1 receptor antagonist (IL-1Ra). Participant questionnaire responses provided information on pre-pregnancy BMI, health, race, educational attainment, and infant birthweight. Bivariate correlations and multiple linear regression models were utilized to evaluate associations by race between preconception adiposity, inflammatory markers and PGH.

RESULTS

After controlling for covariates including maternal age and education, gestational age, and fetal sex, regression models indicated that pre-pregnancy BMI was negatively associated with PGH (β=-0.42, p<0.05) and IL-8 was positively associated with PGH (β=0.35, p<0.05) among the Black mothers only; neither were significantly associated with PGH in the White mothers. When extending models to birth outcomes, BMI was positively associated with birthweight corrected for gestational age (BWz) (β=0.24, p<0.05) and educational attainment was negatively associated with BWz (β=0.28, p<0.05) for infants of White women. In contrast, neither variable was predictive of BWz for infants of Black mothers.

CONCLUSION

Future work is needed to investigate racial differences in the association between adiposity and placental functioning, which are likely to contribute to differential effects on pregnancy outcomes and fetal growth.

Prenatal Stress and the Developing Brain: Postnatal Environments Promoting Resilience

Heightened maternal stress during pregnancy is associated with atypical brain development and an elevated risk for psychopathology in offspring. Supportive environments during early postnatal life may promote brain development and reverse atypical developmental trajectories induced by prenatal stress. We reviewed studies focused on the role of key early environmental factors in moderating associations between prenatal stress exposure and infant brain and neurocognitive outcomes. Specifically, we focused on the associations between parental caregiving quality, environmental enrichment, social support, and socioeconomic status with infant brain and neurocognitive outcomes. We examined the evidence that these factors may moderate the effects of prenatal stress on the developing brain. Complementing findings from translational models, human research suggests that high-quality early postnatal environments are associated with indices of infant neurodevelopment that have also been associated with prenatal stress, such as hippocampal volume and frontolimbic connectivity. Human studies also suggest that maternal sensitivity and higher socioeconomic status may attenuate the effects of prenatal stress on established neurocognitive and neuroendocrine mediators of risk for psychopathology, such as hypothalamic-pituitary-adrenal axis functioning. Biological pathways that may underlie the effects of positive early environments on the infant brain, including the epigenome, oxytocin, and inflammation, are also discussed. Future research in humans should examine resilience-promoting processes in relation to infant brain development using large sample sizes and longitudinal designs. The findings from this review could be incorporated into clinical models of risk and resilience during the perinatal period and used to design more effective early programs that reduce risk for psychopathology.

SARS-CoV-2 (COVID-19) as a possible risk factor for neurodevelopmental disorders

Pregnant women constitute one of the most vulnerable populations to be affected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, the cause of coronavirus disease 2019. SARS-CoV-2 infection during pregnancy could negatively impact fetal brain development via multiple mechanisms. Accumulating evidence indicates that mother to fetus transmission of SARS-CoV-2 does occur, albeit rarely. When it does occur, there is a potential for neuroinvasion via immune cells, retrograde axonal transport, and olfactory bulb and lymphatic pathways. In the absence of maternal to fetal transmission, there is still the potential for negative neurodevelopmental outcomes as a consequence of disrupted placental development and function leading to preeclampsia, preterm birth, and intrauterine growth restriction. In addition, maternal immune activation may lead to hypomyelination, microglial activation, white matter damage, and reduced neurogenesis in the developing fetus. Moreover, maternal immune activation can disrupt the maternal or fetal hypothalamic-pituitary-adrenal (HPA) axis leading to altered neurodevelopment. Finally, pro-inflammatory cytokines can potentially alter epigenetic processes within the developing brain. In this review, we address each of these potential mechanisms. We propose that SARS-CoV-2 could lead to neurodevelopmental disorders in a subset of pregnant women and that long-term studies are warranted.

Maternal blood inflammatory marker levels increased in fetuses with ventriculomegaly

Background

Fetal ventriculomegaly (VM) is one of the most common abnormalities of the central nervous system (CNS), which can be significantly identified by brain anomalies prenatally by magnetic resonance imaging (MRI). Aberrant white blood cells (WBCs) levels indicate that the maternal is suffering from the infection. Previous studies have confirmed that prenatal infection can affect fetal brain structure, but there is no research revealed the association between maternal blood parameters with fetal VM until now.

Methods

We measured the width of the lateral ventricle of 142 fetuses, which were divided into the fetal VM group (n = 70) and the normal lateral ventricle group (n = 72). We compared maternal blood cell levels between the two groups and investigate potential biomarkers of fetal VM.

Result

High levels of maternal WBC and neutrophil (NE#) levels were observed in fetuses with VM (p < 0.001), while lymphocyte percentage, monocytes (MO#), neutrophil/lymphocyte ratio (NLR), and platelet were also increased in the fetal VM group (p = 0.033, 0.027, 0.034, and 0.025, respectively). receiver-operator curve (ROC) analysis suggested that WBC and NE# counts might be useful to distinguish fetuses with enlarged lateral ventricles (AUC = 0.688, 0.678, respectively).

Conclusion

The current study emphasizes the importance of maternal infection for fetal brain growth, which could provide important information for prenatal diagnosis of CNS anomalies. Future research needs longitudinal analysis and exploration of the influence of maternal blood inflammatory marker levels on fetal brain development.

Maternal infections during pregnancy and child cognitive outcomes

Background

Maternal prenatal infections have been linked to children’s neurodevelopment and cognitive outcomes. It remains unclear, however, whether infections occurring during specific vulnerable gestational periods can affect children’s cognitive outcomes. The study aimed to examine maternal infections in each trimester of pregnancy and associations with children’s developmental and intelligence quotients. The ALSPAC birth cohort was used to investigate associations between maternal infections in pregnancy and child cognitive outcomes.

Methods

Infection data from mothers and cognition data from children were included with the final study sample size comprising 7,410 mother-child participants. Regression analysis was used to examine links between maternal infections occurring at each trimester of pregnancy and children’s cognition at 18 months, 4 years, and 8 years.

Results

Infections in the third trimester were significantly associated with decreased verbal IQ at age 4 (p < .05, adjusted R2 = 0.004); decreased verbal IQ (p < .01, adjusted R2 = 0.001), performance IQ (p < .01, adjusted R2 = 0.0008), and total IQ at age 8 (p < .01, adjusted R2 = 0.001).

Conclusion

Results suggest that maternal infections in the third trimester could have a latent effect on cognitive development, only emerging when cognitive load increases over time, though magnitude of effect appears to be small. Performance IQ may be more vulnerable to trimester-specific exposure to maternal infection as compared to verbal IQ. Future research could include examining potential mediating mechanisms on childhood cognition, such as possible moderating effects of early childhood environmental factors, and if effects persist in future cognitive outcomes.

Changes in the geometry and robustness of diffusion tensor imaging networks: Secondary analysis from a randomized controlled trial of young autistic children receiving an umbilical cord blood infusion

Diffusion tensor imaging (DTI) has been used as an outcome measure in clinical trials for several psychiatric disorders but has rarely been explored in autism clinical trials. This is despite a large body of research suggesting altered white matter structure in autistic individuals. The current study is a secondary analysis of changes in white matter connectivity from a double-blind placebo-control trial of a single intravenous cord blood infusion in 2-7-year-old autistic children (1). Both clinical assessments and DTI were collected at baseline and 6 months after infusion. This study used two measures of white matter connectivity: change in node-to-node connectivity as measured through DTI streamlines and a novel measure of feedback network connectivity, Ollivier-Ricci curvature (ORC). ORC is a network measure which considers both local and global connectivity to assess the robustness of any given pathway. Using both the streamline and ORC analyses, we found reorganization of white matter pathways in predominantly frontal and temporal brain networks in autistic children who received umbilical cord blood treatment versus those who received a placebo. By looking at changes in network robustness, this study examined not only the direct, physical changes in connectivity, but changes with respect to the whole brain network. Together, these results suggest the use of DTI and ORC should be further explored as a potential biomarker in future autism clinical trials. These results, however, should not be interpreted as evidence for the efficacy of cord blood for improving clinical outcomes in autism. This paper presents a secondary analysis using data from a clinical trial that was prospectively registered with ClinicalTrials.gov(NCT02847182).

Immune Responses to SARS-CoV-2 in Pregnancy: Implications for the Health of the Next Generation

Widespread SARS-CoV-2 infection among pregnant individuals has led to a generation of fetuses exposed in utero, but the long-term impact of such exposure remains unknown. Although fetal infection is rare, children born to mothers with SARS-CoV-2 infection may be at increased risk for adverse neurodevelopmental and cardiometabolic outcomes. Fetal programming effects are likely to be mediated at least in part by maternal immune activation. In this review, we discuss recent evidence regarding the effects of prenatal SARS-CoV-2 infection on the maternal, placental, and fetal immune response, as well as the implications for the long-term health of offspring. Extrapolating from what is known about the impact of maternal immune activation in other contexts (e.g., obesity, HIV, influenza), we review the potential for neurodevelopmental and cardiometabolic morbidity in offspring. Based on available data suggesting potential increased neurodevelopmental risk, we highlight the importance of establishing large cohorts to monitor offspring born to SARS-CoV-2-positive mothers for neurodevelopmental and cardiometabolic sequelae.

Antenatal maternal depression, early life inflammation and neurodevelopment in a South African birth cohort

BACKGROUND

Antenatal exposure to maternal psychological adversity, including depression, increases the risk of impaired neurodevelopment in children. The underlying biological mechanisms remain unclear, especially in early life during critical windows of development and maturation. This study investigated the association of antenatal maternal depression, maternal and early life inflammatory markers and neurodevelopmental outcomes in children at 2 years of age.

METHODS

A subgroup of mothers and their children (n = 255) that were enrolled in a South African birth cohort study, the Drakenstein Child Health Study, were followed from the antenatal period through to 2 years of child age. Maternal depressive symptoms were measured by the Beck Depression Inventory (BDI-II) at 26 weeks gestation. Serum inflammatory markers [granulocyte-macrophage colony-stimulating factor (GM-CSF), interferon-γ (IFN-γ), interleukin IL-1β, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12p70, IL-13, tumour necrosis factor-α (TNF-α), neutrophil gelatinase-associated lipocalin (NGAL) and metalloproteinase-9 (MMP-9)] were measured in mothers at enrolment and in their children at 6-10 weeks and at 2 years. Neurodevelopment was assessed at 2 years using the Bayley Scales of Infant and Toddler Development III.

RESULTS

Antenatal depressive symptoms (present in 25% of the mothers) were significantly associated with higher levels of IL-7 (p = 0.008), IL-8 (p = 0.019) and TNF-α (p = 0.031) in the mothers after correcting for sociodemographic and lifestyle factors. Serum IL-1β and NGAL levels were significantly elevated over time in children born to mothers with depressive symptoms compared to those without depression, after controlling for maternal and child health and sociodemographic factors. Elevated infant IL-1β at 6-10 weeks of age partially mediated the association of maternal depressive symptoms with poorer language scores at 2 years.

CONCLUSION

Alterations in early life immunity, as reflected by elevated IL-1β, is a potential pathway through which antenatal maternal depressive symptoms may impact language development in young children.

Impact of Maternal Immune Activation on Nonhuman Primate Prefrontal Cortex Development: Insights for Schizophrenia

Late adolescence is a period of dynamic change in the brain as humans learn to navigate increasingly complex environments. In particular, prefrontal cortical (PFC) regions undergo extensive remodeling as the brain is fine-tuned to orchestrate cognitive control over attention, reasoning, and emotions. Late adolescence also presents a uniquely vulnerable period as neurodevelopmental illnesses, such as schizophrenia, become evident and worsen into young adulthood. Challenges in early development, including prenatal exposure to infection, may set the stage for a cascade of maladaptive events that ultimately result in aberrant PFC connectivity and function before symptoms emerge. A growing body of research suggests that activation of the mother's immune system during pregnancy may act as a disease primer, in combination with other environmental and genetic factors, contributing to an increased risk of neurodevelopmental disorders, including schizophrenia. Animal models provide an invaluable opportunity to examine the course of brain and behavioral changes in offspring exposed to maternal immune activation (MIA). Although the vast majority of MIA research has been carried out in rodents, here we highlight the translational utility of the nonhuman primate (NHP) as a model species more closely related to humans in PFC structure and function. In this review, we consider the protracted period of brain and behavioral maturation in the NHP, describe emerging findings from MIA NHP offspring in the context of rodent preclinical models, and lastly explore the translational relevance of the NHP MIA model to expand understanding of the etiology and developmental course of PFC pathology in schizophrenia.

Effect of advanced parental age on pregnancy outcome and offspring health

PURPOSE

Fertility at advanced age has become increasingly common, but the aging of parents may adversely affect the maturation of gametes and the development of embryos, and therefore the effects of aging are likely to be transmitted to the next generation. This article reviewed the studies in this field in recent years.

METHODS

We searched the relevant literature in recent years with the keywords of "advanced maternal/paternal age" combined with "adverse pregnancy outcome" or "birth defect" in the PubMed database and classified the effects of parental advanced age on pregnancy outcomes and birth defects. Related studies on the effect of advanced age on birth defects were classified as chromosomal abnormalities, neurological and psychiatric disorders, and other systemic diseases. The effect of assisted reproduction technology (ART) on fertility in advanced age was also discussed.

RESULTS

Differences in the definition of the range of advanced age and other confounding factors among studies were excluded, most studies believed that advanced parental age would affect pregnancy outcomes and birth defects in offspring.

CONCLUSION

To some extent, advanced parental age caused adverse pregnancy outcomes and birth defects. The occurrence of these results was related to the molecular genetic changes caused by aging, such as gene mutations, epigenetic variations, etc. Any etiology of adverse pregnancy outcomes and birth defects related to aging might be more than one. The detrimental effect of advanced age can be corrected to some extent by ART.

No evidence for association between late pregnancy maternal cortisol and gray matter volume in a healthy community sample of young adolescents

A compelling amount of animal and human research has shown that perceived maternal stress during pregnancy can affect the neurodevelopment of the offspring. Prenatal maternal cortisol is frequently proposed as the biological key mechanism underlying this link; however, literature that investigates the effects of prenatal cortisol on subsequent neurodevelopment in humans is scarce. By using longitudinal data from a relatively large community sample of mother-child dyads (N = 73), this pre-registered study prospectively examined the role of maternal prenatal cortisol concentrations on subsequent individual differences in gray matter volume (GMV) and hippocampal subfield volumes at the onset of puberty of the offspring (12 years of age). Two markers of cortisol, that is, evening cortisol and circadian decline over the day, were used as indicators of maternal physiological stress during the last trimester of pregnancy. The results indicate that prenatal maternal cortisol levels were not associated with GMV or hippocampal subfield volumes of the children. These findings suggest that late pregnancy maternal cortisol may not be related to the structural development of the offspring's brain, at least not in healthy community samples and at the onset of puberty. When examining the influence of prenatal stress on offspring neurodevelopment, future investigations should delineate gestational timing effects of the cortisol exposure, cortisol assessment method, and impact of additional biomarkers, as these were not investigated in this study.

Testing a cascade model linking prenatal inflammation to child executive function

Inflammation during pregnancy is beginning to be understood as a risk factor predicting poor infant health and neurodevelopmental outcomes. The long-term sequelae associated with exposure to prenatal inflammation are less well established. The current study examined associations between maternal inflammation during pregnancy, markers of infant neurodevelopment (general cognitive ability, negative affect, and sleep quality), and preschool executive function (EF) in a longitudinal sample of 40 African American mother-infant dyads. Mothers completed a blood draw in the third trimester of pregnancy to measure plasma levels of C-reactive protein (CRP) and pro-inflammatory cytokines (e.g., interleukin 6 [IL-6], tumor necrosis factor-alpha [TNF-α]). When infants were 6 months of age, we assessed general cognitive ability via the Bayley-III, negative affect via the Still-Face Paradigm, and sleep quality via actigraphy monitoring. When children were 4 years of age, we assessed their EF ability using four tasks from the EF Touch battery. Elevated levels of maternal CRP, IL-6, and TNF-α were associated with poorer infant general cognitive ability. Although there were no direct effects of prenatal inflammation on preschool EF, we observed an indirect relationship between IL-6 and preschool EF ability via infant general cognitive ability. Our findings suggest that prenatal inflammation may have long-lasting, cascading implications for child neurodevelopment. Implications of these findings for health disparities in women and children of color are discussed.

Sex-specific association between placental inflammatory cytokine mRNA expression and preschoolers' behavioral development: The Ma'anshan birth cohort study

BACKGROUND

Placental inflammation may contribute to brain abnormalities and childhood neuropsychiatric disorders, but limited knowledge is available on the association of placental inflammatory cytokine levels and offspring's behavioral development. This study aimed to examine the sex-specific association between placental inflammatory cytokine mRNA expression and preschoolers' behavioral development.

METHODS

3474 pregnant women were recruited as the initial study population in the Ma'anshan birth cohort (MABC) study. Placentas (n = 2519) were collected during childbirth, and the mRNA expression of IL-8, IL-1β, CRP, TNF-α, IL-6, IL-10, and IL-4 was assessed. The Child Behavior Checklist 1.5-5 (CBCL 1.5-5) was used to assess children's behavioral development at 4 years old. A T-score ≥ 60 on summary scales or a score ≥ 65 on syndrome scales was regarded as the borderline clinical range. Multiple linear regression models and binary logistic regression models were applied to explore the sex-specific associations between placental inflammatory cytokines mRNA transcript levels and preschoolers' behavioral development.

RESULTS

Sex-specific associations between placental inflammatory cytokines mRNA expression and preschoolers' behavioral development were observed. There was a positive association between IL-8 and CBCL scores for boys on anxious/depressed problems, aggressive behaviors, externalizing problems and total problems. Logistic regression models showed that high levels of IL-8 were associated with a higher risk of girls' emotionally reactive problems and sleep problems compared to low/medium levels. High TNF-α was correlated with increased sleep problem scores in boys, and medium TNF-α (vs. low levels) was associated with an increased risk of girls' externalizing problems. Medium levels of CRP, IL-1β, and IL-6 were found to be associated with a decreased risk of girls' behavioral problems compared to low/high levels. For anti-inflammatory cytokines, medium IL-10 and IL-4 (vs. low levels) were observed to be associated with a lower risk of internalizing problems in boys and externalizing problems in girls, respectively. High IL-10 was correlated with decreased attention problem scores in boys.

CONCLUSION

This study indicates that placental inflammatory cytokine mRNA expression of IL-8, CRP, TNF-α, IL-1β, IL-4 and IL-10 may be associated with preschoolers' behavioral development in a sex-specific manner.

Birth of the blues: emotional sound processing in infants exposed to prenatal maternal depression

BACKGROUND

Offspring exposed to prenatal maternal depression (PMD) are vulnerable to depression across their lifespan. The underlying cause(s) for this elevated intergenerational risk is most likely complex. However, depression is underpinned by a dysfunctional frontal-limbic network, associated with core information processing biases (e.g. attending more to sad stimuli). Aberrations in this network might mediate transmission of this vulnerability in infants exposed to PMD. In this study, we aimed to explore the association between foetal exposure to PMD and frontal-limbic network function in infancy, hypothesising that, in response to emotional sounds, infants exposed to PMD would exhibit atypical activity in these regions, relative to those not exposed to PMD.

METHOD

We employed a novel functional magnetic resonance imaging sequence to compare brain function, whilst listening to emotional sounds, in 78 full-term infants (3-6 months of age) born to mothers with and without a diagnosis of PMD.

RESULTS

After exclusion of 19 datasets due to infants waking up, or moving excessively, we report between-group brain activity differences, between 29 infants exposed to PMD and 29 infants not exposed to PMD, occurring in temporal, striatal, amygdala/parahippocampal and frontal regions (p < 0.005). The offspring exposed to PMD exhibited a relative increase in activation to sad sounds and reduced (or unchanged) activation to happy sounds in frontal-limbic clusters.

CONCLUSIONS

Findings of a differential response to positive and negative valanced sounds by 3-6 months of age may have significant implications for our understanding of neural mechanisms that underpin the increased risk for later-life depression in this population.

The long-term impact of elevated C-reactive protein levels during pregnancy on brain morphology in late childhood

IMPORTANCE

Animal studies show that Maternal Immune Activation (MIA) may have detrimental effects on fetal brain development. Clinical studies provide evidence for structural brain abnormalities in human neonates following MIA, but no study has investigated the long-term effects of MIA (as measured with biomarkers) on human brain morphology ten years after the exposure.

OBJECTIVE

Our aim was to evaluate the long-term impact of MIA on brain morphology in 10-year-old children, including the possible mediating role of gestational age at birth.

DESIGN

We leveraged data from Generation R, a large-scale prospective pregnancy cohort study. Pregnant women were included between 2002 and 2006, and their children were invited to participate in the MRI study between 2013 and 2015. To be included, mother-child dyads had to have data on maternal C-reactive protein levels during gestation and a good quality MRI-scan of the child's brain at age 10 years. Of the 3,992 children scanned, a total of 2,053 10-year-old children were included in this study.

EXPOSURE

Maternal C-reactive protein was measured in the first 18 weeks of gestation. For the analyses we used both a continuous approach as well as a categorical approach based on clinical cut-offs to determine if there was a dose-response relationship.

MAIN OUTCOMES AND MEASURES

High-resolution MRI brain morphology measures were used as the primary outcome. Gestational age at birth, established using ultrasound, was included as a mediator using a causal mediation analysis. Corrections were made for relevant confounders and multiple comparisons. Biological sex was investigated as moderator.

RESULTS

We found a direct association between continuous MIA and lower cerebellar volume. In girls, we demonstrated a negative indirect association between continuous MIA and total brain volume, through the mediator gestational age at birth. We observed no associations with categorical MIA after multiple testing correction.

CONCLUSION AND RELEVANCE

Our results suggest sex-specific long-term effects in brain morphology after MIA. Categorical analyses suggest that this association might be driven by acute infections or other sources of severe inflammation, which is of clinical relevance given that the COVID-19 pandemic is currently affecting millions of pregnant women worldwide.

Maternal free fatty acid concentration during pregnancy is associated with newborn hypothalamic microstructure in humans

OBJECTIVE

This study tested the hypothesis, in a prospective cohort study design, that maternal saturated free fatty acid (sFFA) concentration during pregnancy is prospectively associated with offspring (newborn) hypothalamic (HTH) microstructure and to explore the functional relevance of this association with respect to early-childhood body fat percentage (BF%).

METHODS

In N = 94 healthy newborns (born mean 39.3 [SD 1.5] weeks gestation), diffusion-weighted magnetic resonance imaging was performed shortly after birth (25.3 [12.5] postnatal days), and a subgroup (n = 37) underwent a dual-energy x-ray absorptiometry scan in early childhood (4.7 [SD 0.7] years). Maternal sFFA concentration during pregnancy was quantified in fasting blood samples via liquid chromatography-mass spectrometry. Infant HTH microstructural integrity was characterized using mean diffusivity (MD). Multiple linear regression was used to test the association between maternal sFFA and HTH MD, accounting for newborn sex, age at scan, mean white matter MD, and image quality. Multiple linear regression models also tested the association between HTH MD and early-childhood BF%, accounting for breastfeeding status.

RESULTS

Maternal sFFA during pregnancy accounted for 8.3% of the variation in newborn HTH MD (β-std = 0.25; p = 0.006). Furthermore, newborn HTH MD prospectively accounted for 15% of the variation in early-childhood BF% (β-std = 0.32; p = 0.019).

CONCLUSIONS

These findings suggest that maternal overnutrition during pregnancy may influence the development of the fetal hypothalamus, which, in turn, may have clinical relevance for childhood obesity risk.

Distinct effects of interleukin-6 and interferon-γ on differentiating human cortical neurons

Translational evidence suggests that cytokines involved in maternal immune activation (MIA), such as interleukin-6 (IL-6) and interferon-γ (IFN-γ), can cross the placenta, injure fetal brain, and predispose to neuropsychiatric disorders. To elaborate developmental neuronal sequelae of MIA, we differentiated human pluripotent stem cells to cortical neurons over a two-month period, exposing them to IL-6 or IFN-γ. IL-6 impacted expression of genes regulating extracellular matrix, actin cytoskeleton and TGF-β signaling while IFN-γ impacted genes regulating antigen processing, major histocompatibility complex and endoplasmic reticulum biology. IL-6, but not IFN-γ, altered mitochondrial respiration while IFN-γ, but not IL-6, induced reduction in dendritic spine density. Pre-treatment with folic acid, which has known neuroprotective and anti-inflammatory properties, ameliorated IL-6 effects on mitochondrial respiration and IFN-γ effects on dendritic spine density. These findings suggest distinct mechanisms for how fetal IL-6 and IFN-γ exposure influence risk for neuropsychiatric disorders, and how folic acid can mitigate such risk.