Elevated maternal C-reactive protein and autism in a national birth cohort

Prenatal immune activation alters the adult neural epigenome but can be partly stabilised by a n-3 polyunsaturated fatty acid diet

An unstable epigenome is implicated in the pathophysiology of neurodevelopmental disorders such as schizophrenia and autism. This is important because the epigenome is potentially modifiable. We have previously reported that adult offspring exposed to maternal immune activation (MIA) prenatally have significant global DNA hypomethylation in the hypothalamus. However, what genes had altered methylation state, their functional effects on gene expression and whether these changes can be moderated, have not been addressed. In this study, we used next-generation sequencing (NGS) for methylome profiling in a MIA rodent model of neurodevelopmental disorders. We assessed whether differentially methylated regions (DMRs) affected the chromatin state by mapping known DNase I hypersensitivity sites (DHSs), and selected overlapping genes to confirm a functional effect of MIA on gene expression using qPCR. Finally, we tested whether methylation differences elicited by MIA could be limited by post-natal dietary (omega) n-3 polyunsaturated fatty acid (PUFA) supplementation. These experiments were conducted using hypothalamic brain tissue from 12-week-old offspring of mice injected with viral analogue PolyI:C on gestation day 9 of pregnancy or saline on gestation day 9. Half of the animals from each group were fed a diet enriched with n-3 PUFA from weaning (MIA group, n = 12 units, n = 39 mice; Control group, n = 12 units, n = 38 mice). The results confirmed our previous finding that adult offspring exposed to MIA prenatally had significant global DNA hypomethylation. Furthermore, genes linked to synaptic plasticity were over-represented among differentially methylated genes following MIA. More than 80% of MIA-induced hypomethylated sites, including those affecting chromatin state and MECP2 binding, were stabilised by the n-3 PUFA intervention. MIA resulted in increased expression of two of the 'top five' genes identified from an integrated analysis of DMRs, DHSs and MECP2 binding sites, namely Abat (t = 2.46, p < 0.02) and Gnas9 (t = 2.96, p < 0.01), although these changes were not stabilised by dietary intervention. Thus, prenatal MIA exposure impacts upon the epigenomic regulation of gene pathways linked to neurodevelopmental conditions; and many of the changes can be attenuated by a low-cost dietary intervention.

Concentrations of immune marker in newborn dried blood spots and early childhood development: Results from the Upstate KIDS Study

BACKGROUND

Evidence shows cytokine dysregulation in children with developmental disabilities. The association between immune activity during the perinatal period and child development is less clear.

METHODS

We examined the relationship between newborn concentrations of immune markers and child development. Within Upstate KIDS, a population-based birth cohort (2008-2010, upstate New York), we assayed immune markers, which are postulated to have neuro-modulatory effects, in newborn dried blood spots (NDBS, n = 3038). Mothers completed the Ages & Stages Questionnaire© (ASQ) for their children repeatedly through age 36 months. At 30 and 36 months, mothers also reported whether their children received any developmental services. We used generalised linear mixed models adjusted for maternal and child characteristics to test associations.

RESULTS

Sixteen immune markers were associated with failing ASQ in unadjusted models. After full adjustment (for gestational age, mode of delivery, parity, pregnancy smoking, etc.), we observed that higher levels of 4 markers, including platelet-derived growth factor-AA (PDGF-AA, OR 0.77, 95% CI 0.67, 0.89), plasminogen activator inhibitor-1 (OR 0.80, 95% CI 0.68, 0.94), stromal cell derived factor-1 (OR 0.85, 95% CI 0.73, 0.98), and macrophage inflammatory protein-1beta (OR 0.87, 95% CI 0.77, 0.98) were associated with lower odds of ASQ failure. The associations did not exist if correction for multiple comparisons was performed, except for PDGF-AA. Analyses with developmental service use revealed similar null findings.

CONCLUSIONS

Immune marker concentrations in NDBS may not be associated with developmental delay in the general population. Newborn concentrations of growth factor PDGF-AA may be protective of developmental delay in childhood.

Pre- and Perinatal Risk Factors for Serious Mental Disorders: Ethical Considerations in Prevention and Prediction Efforts

Repeated findings have linked pre- and perinatal risk factors to a variety of mental disorders. Some studies have found large magnitudes of association, suggesting that fetal development represents an important period for understanding neurodevelopmental sequelae. Nevertheless, it remains unclear how best to translate the existing findings into early identification, prevention, and treatment strategies that would be useful for pregnant populations and/or for their offspring. This article will discuss key ethical considerations surrounding the incorporation of findings from studies of the associations between obstetric complications and risk for mental disorders into prevention and prediction efforts.

A modified ketogenic gluten-free diet with MCT improves behavior in children with autism spectrum disorder

Purpose

The ketogenic diet is a low-carbohydrate, moderate protein, high-fat diet that has emerged as a potential treatment for autism spectrum disorder. Autism spectrum disorder is a neurodevelopmental disorder of social communication, and restricted, repetitive behaviors and interests in need of novel therapies. An open-label clinical trial was done in Honolulu, Hawaii to test a modified ketogenic diet for improvement of core clinical impairments in children with ASD.

Intervention

A modified ketogenic gluten-free diet regimen with supplemental MCT was completed in 15 children ages 2 to 17 years for 3 months. Clinical (ADOS-2, CARS-2) and biochemical measures were performed at baseline and 3-months on the ketogenic diet.

Main outcome

Children administered a modified ketogenic gluten-free diet with supplemental MCT significantly improved core autism features assessed from the ADOS-2 after 3 months on diet (P = 0.006). No significant difference was observed in restricted and repetitive behavior score (P = 0.125) after 3 months on the diet protocol. Substantial improvement (> 30% decrease ADOS-2 total score) was observed in six participants, moderate improvement (> 3 units) in two participants, and minor/no improvement in seven participants. Ten participants assessed at a six-month time point sustained improvement in total ADOS-2 and social affect subdomain scores comparing baseline and 6 months (P = 0.019; P = 0.023), but no significant improvement in restricted and repetitive behavior scores were noted (P = 0.197). Significant improvements in CARS-2 items after 3 months of the modified ketogenic protocol were observed in imitation, body use, and fear or nervousness (P = 0.031, P = 0.008, P = 0.039). The percent change on ADOS-2 score from baseline to 3 months was associated with baseline high-density lipoprotein levels (ρ = −0.67, P = 0.007) and albumin levels (ρ = −0.60, P = 0.019). Moreover, the percent change from baseline to 3 months in ADOS-2 scores was significantly associated with percent change in high-density lipoprotein levels (ρ = 0.54, P = 0.049) and albumin levels (ρ = 0.67, P = 0.010).

Conclusions

A modified gluten-free ketogenic diet with supplemental MCT is a potentially beneficial treatment option to improve the core features of autism spectrum disorder and warrants further investigation.

Trial registration

Trial Registry: Clinicaltrials.gov Registration Number: NCT02477904 URL: https://www.clinicaltrials.gov/ct2/show/NCT02477904?term=ketogenic+diet&cond=Autism&rank=1

Microglia and Beyond: Innate Immune Cells As Regulators of Brain Development and Behavioral Function

Innate immune cells play a well-documented role in the etiology and disease course of many brain-based conditions, including multiple sclerosis, Alzheimer's disease, traumatic brain and spinal cord injury, and brain cancers. In contrast, it is only recently becoming clear that innate immune cells, primarily brain resident macrophages called microglia, are also key regulators of brain development. This review summarizes the current state of knowledge regarding microglia in brain development, with particular emphasis on how microglia during development are distinct from microglia later in life. We also summarize the effects of early life perturbations on microglia function in the developing brain, the role that biological sex plays in microglia function, and the potential role that microglia may play in developmental brain disorders. Finally, given how new the field of developmental neuroimmunology is, we highlight what has yet to be learned about how innate immune cells shape the development of brain and behavior.

Maternal immune activation dysregulation of the fetal brain transcriptome and relevance to the pathophysiology of autism spectrum disorder

Maternal immune activation (MIA) via infection during pregnancy is known to increase risk for autism spectrum disorder (ASD). However, it is unclear how MIA disrupts fetal brain gene expression in ways that may explain this increased risk. Here we examine how MIA dysregulates rat fetal brain gene expression (at a time point analogous to the end of the first trimester of human gestation) in ways relevant to ASD-associated pathophysiology. MIA downregulates expression of ASD-associated genes, with the largest enrichments in genes known to harbor rare highly penetrant mutations. MIA also downregulates expression of many genes also known to be persistently downregulated in the ASD cortex later in life and which are canonically known for roles in affecting prenatally late developmental processes at the synapse. Transcriptional and translational programs that are downstream targets of highly ASD-penetrant FMR1 and CHD8 genes are also heavily affected by MIA. MIA strongly upregulates expression of a large number of genes involved in translation initiation, cell cycle, DNA damage and proteolysis processes that affect multiple key neural developmental functions. Upregulation of translation initiation is common to and preserved in gene network structure with the ASD cortical transcriptome throughout life and has downstream impact on cell cycle processes. The cap-dependent translation initiation gene, EIF4E, is one of the most MIA-dysregulated of all ASD-associated genes and targeted network analyses demonstrate prominent MIA-induced transcriptional dysregulation of mTOR and EIF4E-dependent signaling. This dysregulation of translation initiation via alteration of the Tsc2-mTor-Eif4e axis was further validated across MIA rodent models. MIA may confer increased risk for ASD by dysregulating key aspects of fetal brain gene expression that are highly relevant to pathophysiology affecting ASD.

Gestational cytokine concentrations and neurocognitive development at 7 years

Gestational inflammation may contribute to brain abnormalities associated with childhood neuropsychiatric disorders. Limited knowledge exists regarding the associations of maternal cytokine levels during pregnancy with offspring neurocognitive development. We assayed the concentrations of five cytokines (interleukin (IL)-6, IL-1β, IL-8, tumor necrosis factor alpha (TNF-α), and IL-10) up to four times in the 2nd and 3rd trimesters of pregnancy using stored prenatal sera from 1366 participants in the New England Family Study (enrollment 1959-1966). Intelligence (IQ), academic achievement, and neuropsychological functioning of singleton offspring were assessed at age 7 years using standardized tests. We used linear mixed models with random effects to estimate the cumulative exposure to each cytokine during 2nd and 3rd trimesters, and then related cumulative cytokine exposure to a wide range of offspring neurocognitive outcomes. We found that children of women with higher levels of the pro-inflammatory cytokine, TNF-α, in the 2nd and 3rd trimesters had lower IQ (B = -2.51, 99% CI: -4.84,-0.18), higher problem scores in visual-motor maturity (B = 0.12, 99% CI: 0.001,0.24), and lower Draw-a-Person test scores (B = -1.28, 99% CI: -2.49,-0.07). Higher gestational levels of IL-8, another pro-inflammatory molecule, were associated with better Draw-a-Person test scores and tactile finger recognition scores. Other cytokines were not associated with our outcome of interest. The opposing directions of associations observed between TNF-α and IL-8 with childhood outcomes suggest pleiotropic effects of gestational inflammation across the domains of neurocognitive functioning. Although the path to psychopathological disturbances in children is no doubt multifactorial, our findings point to a potential role for immune processes in the neurocognitive development of children.

Microglia, the missing link in maternal immune activation and fetal neurodevelopment; and a possible link in preeclampsia and disturbed neurodevelopment?

Disturbances in fetal neurodevelopment have extensively been related to neurodevelopmental disorders in early and later life. Fetal neurodevelopment is dependent on adequate functioning of the fetal immune system. During pregnancy, the maternal immune system is challenged to both tolerate the semi-allogenic fetus and to protect the mother and fetus from microbes. The fetal immune system is influenced by maternal immune disturbances; therefore, perturbations in maternal immunity likely do not only alter pregnancy outcome but also alter fetal neurodevelopment. A possible common pathway could be modulating the functioning of tissue macrophages in the placenta and brain. Maternal immune tolerance towards the fetus involves several complex adaptations. In this active maternal immune state, the fetus develops its own immunity. As cytokines and other players of the immune system -which can pass the placenta- are involved in neurodevelopment, disruptions in immune balance influence fetal neurodevelopment. Several studies reported an association between maternal immune activation, complications of pregnancy as preeclampsia, and altered neonatal neurodevelopment. A possible pathway involves dysfunctioning of microglia cells, the immune cells of the brain. Functionality of microglia cells during normal pregnancy is, however, poorly understood. The recent outbreak of ZIKA virus (ZKV), but also the literature on virus infections in general and its consequences on microglial cell function and fetal neurodevelopment show the devastating effects a virus infection during pregnancy can have.

Placental Morphology Is Associated with Maternal Depressive Symptoms during Pregnancy and Toddler Psychiatric Problems

Maternal depressive symptoms during pregnancy predict increased psychiatric problems in children. The underlying biological mechanisms remain unclear. Hence, we examined whether alterations in the morphology of 88 term placentas were associated with maternal depressive symptoms during pregnancy and psychiatric problems in 1.9-3.1-years old (Mean = 2.1 years) toddlers. Maternal depressive symptoms were rated biweekly during pregnancy with the Center of Epidemiological Studies Depression Scale (n = 86). Toddler psychiatric problems were mother-rated with the Child Behavior Checklist (n = 60). We found that higher maternal depressive symptoms throughout pregnancy [B = -0.24 Standard Deviation (SD) units: 95% Confidence Interval (CI) = -0.46; -0.03: P = 0.03; Mean difference = -0.66 SDs; 95% CI = -0.08; -1.23: P = 0.03; between those with and without clinically relevant depressive symptoms] were associated with lower variability in the placental villous barrier thickness of γ-smooth muscle actin-negative villi. This placental morphological change predicted higher total (B = -0.34 SDs: 95% CI = -0.60; -0.07: P = 0.01) and internalizing (B = -0.32 SDs: 95% CI = -0.56; -0.08: P = 0.01) psychiatric problems in toddlers. To conclude, our findings suggest that both maternal depressive symptoms during pregnancy and toddler psychiatric problems may be associated with lower variability in the villous membrane thickness of peripheral villi in term placentas. This lower heterogeneity may compromise materno-fetal exchange, suggesting a possible role for altered placental morphology in the fetal programming of mental disorders.

Maternal IL-17A in autism

Although autism spectrum disorder (ASD) has a strong genetic basis, its etiology is complex, with several genetic factors likely to be involved as well as environmental factors. Immune dysregulation has gained significant attention as a causal mechanism in ASD pathogenesis. ASD has been associated with immune abnormalities in the brain and periphery, including inflammatory disorders and autoimmunity in not only the affected individuals but also their mothers. Prenatal exposure to maternal immune activation (MIA) has been implicated as an environmental risk factor for ASD. In support of this notion, animal models have shown that MIA results in offspring with behavioral, neurological, and immunological abnormalities similar to those observed in ASD. This raises the question of how MIA exposure can lead to ASD in susceptible individuals. Recent evidence points to a potential inflammation pathway linking MIA-associated ASD with the activity of T helper 17 (Th17) lymphocytes and their effector cytokine interleukin-17A (IL-17A). IL-17A has been implicated from human studies and elevated IL-17A levels in the blood have been found to correlate with phenotypic severity in a subset of ASD individuals. In MIA model mice, elevated IL-17A levels also have been observed. Additionally, antibody blockade to inhibit IL-17A signaling was found to prevent ASD-like behaviors in offspring exposed to MIA. Therefore, IL-17A dysregulation may play a causal role in the development of ASD. The source of increased IL-17A in the MIA mouse model was attributed to maternal Th17 cells because genetic removal of the transcription factor RORγt to selectively inhibit Th17 differentiation in pregnant mice was able to prevent ASD-like behaviors in the offspring. Similar to ASD individuals, the MIA-exposed offspring also displayed cortical dysplasia which could be prevented by inhibition of IL-17A signaling in pregnant mice. This finding reveals one possible cellular mechanism through which ASD-related cognitive and behavioral deficits may emerge following maternal inflammation. IL-17A can exert strong effects on cell survival and differentiation and the activity of signal transduction cascades, which can have important consequences during cortical development on neural function. This review examines IL-17A signaling pathways in the context of both immunity and neural function that may contribute to the development of ASD associated with MIA.

BBOX1 is down-regulated in maternal immune-activated mice and implicated in genetic susceptibility to human schizophrenia

Prenatal exposure to infectious or inflammatory insults can increase the risk of developing neuropsychiatric disorders such as bipolar disorder, autism, and schizophrenia in later life. Gamma-butyrobetaine hydroxylase (BBOX 1) is an enzyme responsible for the biosynthesis of l-carnitine, a key molecule in fatty acid metabolism. This cytosolic dimeric protein belongs to the dioxygenase family. In this study, we investigated whether BBOX 1 expression was related to psychiatric disorder in an animal model. We also conducted a case-control study using 284 schizophrenia patients and 409 controls with single-nucleotide polymorphisms (SNPs) in the 5'-near region of BBOX 1. BBOX 1 expression was increased in the medial frontal cortex of a mouse model of schizophrenia induced by maternal immune activation. Furthermore, the genotype and allele frequencies of two SNPs (rs7939644 and rs10767592) were significantly associated with schizophrenia susceptibility. Our results suggest that BBOX 1 might be associated with maternal immune activation and schizophrenia susceptibility. Therefore, it might be involved in the pathophysiology of schizophrenia.

Characterizing the Interplay Between Autism Spectrum Disorder and Comorbid Medical Conditions: An Integrative Review

Co-occurring medical disorders and associated physiological abnormalities in individuals with autism spectrum disorder (ASD) may provide insight into causal pathways or underlying biological mechanisms. Here, we review medical conditions that have been repeatedly highlighted as sharing the strongest associations with ASD-epilepsy, sleep, as well as gastrointestinal and immune functioning. We describe within each condition their prevalence, associations with behavior, and evidence for successful treatment. We additionally discuss research aiming to uncover potential aetiological mechanisms. We then consider the potential interaction between each group of conditions and ASD and, based on the available evidence, propose a model that integrates these medical comorbidities in relation to potential shared aetiological mechanisms. Future research should aim to systematically examine the interactions between these physiological systems, rather than considering these in isolation, using robust and sensitive biomarkers across an individual's development. A consideration of the overlap between medical conditions and ASD may aid in defining biological subtypes within ASD and in the development of specific targeted interventions.

Maternal Polycystic Ovary Syndrome and Risk for Attention-Deficit/Hyperactivity Disorder in the Offspring

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) is the most common childhood neurodevelopmental disorder, and boys are two to three times more likely to develop ADHD. Maternal polycystic ovary syndrome (PCOS), a common metabolic disorder associated with excess circulating androgens, has been associated with increased risk for autism spectrum disorder in the offspring. In this study, we aimed to investigate whether maternal PCOS increases the risk for ADHD in the offspring.

METHODS

We conducted a matched case-control study using health and population data registers for all children born in Sweden from 1984 to 2008. Maternal PCOS was defined by ICD-coded register diagnosis. The outcome of ADHD was defined as an ICD-coded register diagnosis of ADHD and/or registered prescription of medications to treat ADHD. A total of 58,912 ADHD cases (68.8% male) were identified and matched to 499,998 unaffected controls by sex and birth month and year.

RESULTS

Maternal PCOS increased the odds of offspring ADHD by 42% after adjustment for confounders (odds ratio [OR], 1.42; 95% confidence interval [CI], 1.26-1.58). Exclusion of ADHD cases with comorbid autism spectrum disorder attenuated but did not explain the relationship (OR, 1.34; 95% CI, 1.18-1.52). The risk was somewhat elevated for ADHD with comorbid autism spectrum disorder (OR, 1.76; 95% CI, 1.37-2.26). The risk for ADHD was higher among obese mothers with PCOS (OR, 1.68; 95% CI, 1.31-2.17) and was highest among obese mothers with PCOS and other features of metabolic syndrome (OR, 2.59; 95% CI, 1.02-6.58).

CONCLUSIONS

This study provides evidence that maternal PCOS may subtly influence the neurodevelopment of the offspring, resulting in increased risk for neurodevelopmental disorders such as ADHD.

Animal models for autism in 2017 and the consequential implications to drug discovery

INTRODUCTION

Autism spectrum disorder (ASD) is characterized by deficits in social communication and restricted interests/repetitive behaviors, for which there are currently no approved drug treatments. The core symptoms of ASD vary widely in severity and are often accompanied by other neuropsychiatric disorders. Drug discovery has been challenging because of the lack of understanding of the underlying pathophysiology of ASD as well as the heterogeneity of symptoms and symptom severity. Areas covered: In this review, the author discusses animal models of ASD used as targets for drug discovery, focusing primarily on non-syndromic models, primarily rodents. They highlight the wide range of drug targets examined in animal models. While very little of this work has resulted in drug therapy for the behavioral symptoms of ASD yet, it has increased our knowledge of the biology of ASD that is critical for driving drug discovery and has already provided many new drug targets for investigation. Expert opinion: The information gathered from the animal models of ASD is increasing our understanding of the underlying pathophysiology for ASD and is leading to better therapeutic targets. However, the issue of small sample size, heterogeneity within clinical samples, and a lack of replicable outcome measures must be addressed to move forward.

Immunopsychiatry: important facts

Accumulating evidence indicate a role for the immune system particularly inflammation and autoimmunity in the aetiology of major psychiatric disorders such as depression and schizophrenia. In this paper, we discuss some of the key advances in immunopsychiatry in order to highlight to psychiatrists and other health professionals how an increased understanding of this field might enhance our knowledge of illness mechanism and approaches to treatment. We present a brief overview of clinical research that link inflammation and autoimmunity with depression and psychosis, including potential role of inflammation in treatment response, current evidence for the effectiveness of immune-modulating treatment for depression and psychosis, and possible role of inflammation in common physical comorbidities for these disorders such as coronary heart disease and diabetes mellitus. Gaining a better understanding of the role of immune system could be paradigm changing for psychiatry. We need collaborations between clinicians and scientists to deliver high-quality translational research in order to fully realise the clinical potential of this exciting and rapidly expanding field.

Reversing behavioural abnormalities in mice exposed to maternal inflammation

Viral infection during pregnancy is correlated with increased frequency of neurodevelopmental disorders, and this is studied in mice prenatally subjected to maternal immune activation (MIA). We previously showed that maternal T helper 17 cells promote the development of cortical and behavioural abnormalities in MIA-affected offspring. Here we show that cortical abnormalities are preferentially localized to a region encompassing the dysgranular zone of the primary somatosensory cortex (S1DZ). Moreover, activation of pyramidal neurons in this cortical region was sufficient to induce MIA-associated behavioural phenotypes in wild-type animals, whereas reduction in neural activity rescued the behavioural abnormalities in MIA-affected offspring. Sociability and repetitive behavioural phenotypes could be selectively modulated according to the efferent targets of S1DZ. Our work identifies a cortical region primarily, if not exclusively, centred on the S1DZ as the major node of a neural network that mediates behavioural abnormalities observed in offspring exposed to maternal inflammation.

Maternal gut bacteria promote neurodevelopmental abnormalities in mouse offspring

Maternal immune activation (MIA) contributes to behavioural abnormalities associated with neurodevelopmental disorders in both primate and rodent offspring. In humans, epidemiological studies suggest that exposure of fetuses to maternal inflammation increases the likelihood of developing autism spectrum disorder. In pregnant mice, interleukin-17a (IL-17a) produced by T helper 17 (T_H17) cells (CD4⁺ T helper effector cells involved in multiple inflammatory conditions) induces behavioural and cortical abnormalities in the offspring exposed to MIA. However, it is unclear whether other maternal factors are required to promote MIA-associated phenotypes. Moreover, the underlying mechanisms by which MIA leads to T cell activation with increased IL-17a in the maternal circulation are not well understood. Here we show that MIA phenotypes in offspring require maternal intestinal bacteria that promote T_H17 cell differentiation. Pregnant mice that had been colonized with mouse commensal segmented filamentous bacteria or human commensal bacteria that induce intestinal T_H17 cells were more likely to produce offspring with MIA-associated abnormalities. We also show that small intestine dendritic cells from pregnant, but not from non-pregnant, females secrete IL-1β, IL-23 and IL-6 and stimulate T cells to produce IL-17a upon exposure to MIA. Overall, our data suggest that defined gut commensal bacteria with a propensity to induce T_H17 cells may increase the risk of neurodevelopmental disorders in the offspring of pregnant mothers undergoing immune system activation owing to infections or autoinflammatory syndromes.

Effect of Neuroinflammation on Synaptic Organization and Function in the Developing Brain: Implications for Neurodevelopmental and Neurodegenerative Disorders

The brain is a plastic organ where both the intrinsic CNS milieu and extrinsic cues play important roles in shaping and wiring neural connections. The perinatal period constitutes a critical time in central nervous system development with extensive refinement of neural connections, which are highly sensitive to fetal and neonatal compromise, such as inflammatory challenges. Emerging evidence suggests that inflammatory cells in the brain such as microglia and astrocytes are pivotal in regulating synaptic structure and function. In this article, we will review the role of glia cells in synaptic physiology and pathophysiology, including microglia-mediated elimination of synapses. We propose that activation of the immune system dynamically affects synaptic organization and function in the developing brain. We will discuss the role of neuroinflammation in altered synaptic plasticity following perinatal inflammatory challenges and potential implications for neurodevelopmental and neurodegenerative disorders.

Prenatal exposure to maternal very severe obesity is associated with impaired neurodevelopment and executive functioning in children

BackgroundPrenatal maternal obesity has been associated with an increased risk of neurocognitive problems in childhood, but there are fewer studies on executive functioning.MethodsTests and questionnaires to assess neurodevelopment, executive functioning, and the ability to delay gratification were conducted in 113 children (mean (SD)=4.24 (0.63) years of age) born to mothers with very severe obesity (SO, body mass index (BMI)⩾40 kg/m², n=51) or to lean mothers (BMI⩽25 kg/m², n=62).ResultsPrenatal maternal SO predicted poorer neurodevelopment (unstandardized regression coefficient (B)=-0.42, 95% confidence interval (CI) (-0.82; -0.02)), worse problem-solving (odd ratio (OR)=0.60, 95% CI (1.13; 0.07)), and fine motor skills (OR=4.91, 95% CI (1.27; 19.04)), poorer executive functioning in areas of attention, inhibitory control, and working memory (standardized B=3.75, 95% CI (1.01; 13.93)) but not in self-gratification delay. The effects were independent of maternal concurrent psychological well-being and child's BMI, but not independent of maternal education.ConclusionFuture studies should investigate whether perinatal management of maternal obesity could prevent adverse outcomes in child neurodevelopment.

Socioeconomic disadvantage, gestational immune activity, and neurodevelopment in early childhood

Children raised in economically disadvantaged households face increased risks of poor health in adulthood, suggesting that inequalities in health have early origins. From the child's perspective, exposure to economic hardship may begin as early as conception, potentially via maternal neuroendocrine-immune responses to prenatal stressors, which adversely impact neurodevelopment. Here we investigate whether socioeconomic disadvantage is associated with gestational immune activity and whether such activity is associated with abnormalities among offspring during infancy. We analyzed concentrations of five immune markers (IL-1β, IL-6, IL-8, IL-10, and TNF-α) in maternal serum from 1,494 participants in the New England Family Study in relation to the level of maternal socioeconomic disadvantage and their involvement in offspring neurologic abnormalities at 4 mo and 1 y of age. Median concentrations of IL-8 were lower in the most disadvantaged pregnancies [-1.53 log(pg/mL); 95% CI: -1.81, -1.25]. Offspring of these pregnancies had significantly higher risk of neurologic abnormalities at 4 mo [odds ratio (OR) = 4.61; CI = 2.84, 7.48] and 1 y (OR = 2.05; CI = 1.08, 3.90). This higher risk was accounted for in part by fetal exposure to lower maternal IL-8, which also predicted higher risks of neurologic abnormalities at 4 mo (OR = 7.67; CI = 4.05, 14.49) and 1 y (OR = 2.92; CI = 1.46, 5.87). Findings support the role of maternal immune activity in fetal neurodevelopment, exacerbated in part by socioeconomic disadvantage. This finding reveals a potential pathophysiologic pathway involved in the intergenerational transmission of socioeconomic inequalities in health.

Autism as an adaptive common variant pathway for human brain development

While research on focal perinatal lesions has provided evidence for recovery of function, much less is known about processes of brain adaptation resulting from mild but widespread disturbances to neural processing over the early years (such as alterations in synaptic efficiency). Rather than being viewed as a direct behavioral consequence of life-long neural dysfunction, I propose that autism is best viewed as the end result of engaging adaptive processes during a sensitive period. From this perspective, autism is not appropriately described as a disorder of neurodevelopment, but rather as an adaptive common variant pathway of human functional brain development.

Epigenetic and transgenerational mechanisms in infection-mediated neurodevelopmental disorders

Prenatal infection is an environmental risk factor for various brain disorders with neurodevelopmental components, including autism spectrum disorder and schizophrenia. Modeling this association in animals shows that maternal immune activation negatively affects fetal brain development and leads to the emergence of behavioral disturbances later in life. Recent discoveries in these preclinical models suggest that epigenetic modifications may be a critical molecular mechanism by which prenatal immune activation can mediate changes in brain development and functions, even across generations. This review discusses the potential epigenetic mechanisms underlying the effects of prenatal infections, thereby highlighting how infection-mediated epigenetic reprogramming may contribute to the transgenerational transmission of pathological traits. The identification of epigenetic and transgenerational mechanisms in infection-mediated neurodevelopmental disorders appears relevant to brain disorders independently of existing diagnostic classifications and may help identifying complex patterns of transgenerational disease transmission beyond genetic inheritance. The consideration of ancestral infectious histories may be of great clinical interest and may be pivotal for developing new preventive treatment strategies against infection-mediated neurodevelopmental disorders.

Prenatal toxoplasmosis antibody and childhood autism

There is evidence that some maternal infections during the prenatal period are associated with neurodevelopmental disorders, such as childhood autism. However, the association between autism and Toxoplasma gondii (T. gondii), an intracellular parasite, remains unclear. The authors examined whether serologically confirmed maternal antibodies to T. gondii are associated with odds of childhood autism in offspring. The study is based on a nested case-control design of a large national birth cohort (N = 1.2 million) and the national psychiatric registries in Finland. There were 874 cases of childhood autism and controls matched 1:1 on date of birth, sex, birthplace and residence in Finland. Maternal sera were prospectively assayed from a national biobank for T. gondii IgM and IgG antibodies; IgG avidity analyses were also performed. High maternal T. gondii IgM antibody was associated with a significantly decreased odds of childhood autism. Low maternal T. gondii IgG antibody was associated with increased offspring odds of autism. In women with high T. gondii IgM antibodies, the IgG avidity was high for both cases and controls, with the exception of three controls. The findings suggest that the relationship between maternal T. gondii antibodies and odds of childhood autism may be related to the immune response to this pathogen or the overall activation of the immune system. Autism Res 2017, 10: 769-777. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.

Parental Psychopathology and Tourette Syndrome/Chronic Tic Disorder in Offspring: A Nationwide Case-Control Study

OBJECTIVE

To determine the associations between maternal and paternal psychiatric diagnoses and Tourette syndrome (TS)/chronic tic disorder (CT) in a nationwide study.

METHOD

This nested case-control study linked data derived from three national registers. All singletons born and diagnosed with TS/CT in Finland between January 1991 and December 2010 were identified (n = 1,120) and matched to four controls (n = 4,299). Conditional logistic regression was used to examine the associations between parental psychopathology and TS/CT.

RESULTS

Altogether, 24.9% of patients with TS/CT and 12.0% of controls had a mother with a psychiatric diagnosis. Similarly, 17.9% and 12.9% had a father with a psychiatric diagnosis. Any maternal and any paternal psychiatric diagnosis was associated with offspring TS/CT (odds ratio [OR] 2.3; 95% CI 1.9-2.7 and OR 1.2; 95% CI 1.01-1.5, respectively). The association between maternal psychiatric diagnosis and TS/CT was stronger than that between paternal psychiatric diagnosis and TS/CT (p < .001). Maternal personality disorders (OR 3.1, 95% CI 1.9-5.1), anxiety disorders (OR 2.6, 95% CI 1.9-3.5), affective disorders (OR 2.3, 95% CI 1.8-2.9), psychotic disorders (OR 2.0, 95% CI 1.2-3.3), and addiction disorders (OR 1.8, 95% CI 1.1-2.8) were associated with TS/CT. Paternal OCD (OR 6.5, 95% CI 1.1-39.5) and anxiety disorders (OR 1.5, 95% CI 1.1-2.3) were associated with TS/CT.

CONCLUSION

Parental psychiatric diagnoses (especially in the mother) are associated with diagnosed offspring TS/CT. Further studies are required before the results can be generalized to all children with TS/CT. The associations between maternal psychiatric disorders and TS may reflect both maternal specific environmental and/or genetic influences.

Can C-reactive protein inform antidepressant medication selection in depressed outpatients? Findings from the CO-MED trial

OBJECTIVE

Currently, no valid measures inform treatment selection for depressed patients. Whether C-reactive protein (CRP) in particular and two other acute phase reactants (inflammatory markers) could differentiate between patients responding to either of two treatments with different mechanisms of action was assessed.

METHOD

Subjects included Combining Medications to Enhance Depression Outcomes (CO-MED) trial participants randomly assigned to either escitalopram plus placebo (SSRI monotherapy, n=51) or bupropion plus escitalopram combination (bupropion-SSRI combination, n=55) with baseline plasma samples. CRP, serum amyloid P component, and alpha-2-macroglobulin were measured using the Bioplex Pro™ human acute-phase 4-plex panel. We conducted mixed model analyses of depressive symptom (Quick Inventory of Depressive Symptomatology Self-Report) and side-effect burden (Frequency, Intensity, and Burden of Side-Effects Rating Scale) obtained weekly or every other week over the 12-week acute-phase of CO-MED trial to evaluate the relationship between these outcomes and baseline CRP and other acute-phase reactants.

RESULTS

The treatment arms did not differ in depressive symptom or side effect outcomes. Most participants (69.8%, 74/106) had baseline CRP levels greater than 1mg/L (indicative of systemic inflammatory activity). Higher baseline CRP levels were associated lower depression severity (correlation coefficient=-0.63) with bupropion-SSRI combination but not with SSRI monotherapy (correlation coefficient=0.40). The overall remission rate was 41.5%. The estimated remission rate with CRP threshold based assignment (SSRI monotherapy for <1mg/L and Bupropion-SSRI for ≥1mg/L) was 53.1%, with a number needed to treat of 8.6. Side effect burden was unrelated to any baseline inflammatory marker.

CONCLUSIONS

Baseline CRP levels relate differentially to antidepressant treatment outcomes in persons with major depressive disorder. Clinicaltrials.gov identifier: NCT00590863.

The Changing Epidemiology of Autism Spectrum Disorders

Autism spectrum disorder (ASD) is a complex neurodevelopmental condition with lifelong impacts. Genetic and environmental factors contribute to ASD etiology, which remains incompletely understood. Research on ASD epidemiology has made significant advances in the past decade. Current prevalence is estimated to be at least 1.5% in developed countries, with recent increases primarily among those without comorbid intellectual disability. Genetic studies have identified a number of rare de novo mutations and gained footing in the areas of polygenic risk, epigenetics, and gene-by-environment interaction. Epidemiologic investigations focused on nongenetic factors have established advanced parental age and preterm birth as ASD risk factors, indicated that prenatal exposure to air pollution and short interpregnancy interval are potential risk factors, and suggested the need for further exploration of certain prenatal nutrients, metabolic conditions, and exposure to endocrine-disrupting chemicals. We discuss future challenges and goals for ASD epidemiology as well as public health implications.

Vitamin D treatment during pregnancy prevents autism-related phenotypes in a mouse model of maternal immune activation

BACKGROUND

Prenatal exposure to infection is a recognized environmental risk factor for neuropsychiatric disorders of developmental origins such as autism or schizophrenia. Experimental work in animals indicates that this link is mediated by maternal immune activation (MIA) involving interactions between cytokine-associated inflammatory events, oxidative stress, and other pathophysiological processes such as hypoferremia and zinc deficiency. Maternal administration of the viral mimic polyriboinosinic-polyribocytidylic acid (poly(I:C)) in mice produces several behavioral phenotypes in adult offspring of relevance to autism spectrum disorder (ASD) and other neurodevelopmental disorders.

METHODS

Here, we investigated whether some of these phenotypes might also present in juveniles. In addition, given the known immunomodulatory and neuroprotective effects of vitamin D, we also investigated whether the co-administration of vitamin D could block MIA-induced ASD-related behaviors. We co-administered the hormonally active form of vitamin D, 1α,25 dihydroxy vitamin D3 (1,25OHD), simultaneously with poly(I:C) and examined (i) social interaction, stereotyped behavior, emotional learning and memory, and innate anxiety-like behavior in juveniles and (ii) the levels of the pro-inflammatory cytokines IL-1β, IL-6 and TNF-α in maternal plasma and fetal brains.

RESULTS

We show that like adult offspring that were exposed to MIA, juveniles display similar deficits in social approach behavior. Juvenile MIA offspring also show abnormal stereotyped digging and impaired acquisition and expression of tone-cued fear conditioning. Importantly, our study reveals that prenatal administration of 1,25OHD abolishes all these behavioral deficits in poly(I:C)-treated juveniles. However, prenatal administration of vitamin D had no effect on pro-inflammatory cytokine levels in dams or in fetal brains suggesting the anti-inflammatory actions of vitamin D are not the critical mechanism for its preventive actions in this ASD animal model.

CONCLUSIONS

This work raises the possibility that early dietary supplementation with vitamin D may open new avenues for a successful attenuation or even prevention of neurodevelopmental disorders following maternal inflammation during pregnancy.

Maternal Immune Activation and Autism Spectrum Disorder: From Rodents to Nonhuman and Human Primates

A subset of women who are exposed to infection during pregnancy have an increased risk of giving birth to a child who will later be diagnosed with a neurodevelopmental or neuropsychiatric disorder. Although epidemiology studies have primarily focused on the association between maternal infection and an increased risk of offspring schizophrenia, mounting evidence indicates that maternal infection may also increase the risk of autism spectrum disorder. A number of factors, including genetic susceptibility, the intensity and timing of the infection, and exposure to additional aversive postnatal events, may influence the extent to which maternal infection alters fetal brain development and which disease phenotype (autism spectrum disorder, schizophrenia, other neurodevelopmental disorders) is expressed. Preclinical animal models provide a test bed to systematically evaluate the effects of maternal infection on fetal brain development, determine the relevance to human central nervous system disorders, and to evaluate novel preventive and therapeutic strategies. Maternal immune activation models in mice, rats, and nonhuman primates suggest that the maternal immune response is the critical link between exposure to infection during pregnancy and subsequent changes in brain and behavioral development of offspring. However, differences in the type, severity, and timing of prenatal immune challenge paired with inconsistencies in behavioral phenotyping approaches have hindered the translation of preclinical results to human studies. Here we highlight the promises and limitations of the maternal immune activation model as a preclinical tool to study prenatal risk factors for autism spectrum disorder, and suggest specific changes to improve reproducibility and maximize translational potential.

Associations Between Autoimmune Diseases and Attention-Deficit/Hyperactivity Disorder: A Nationwide Study

OBJECTIVE

Recent studies have suggested that autoimmune diseases and immune activation play a part in the pathogenesis of different neurodevelopmental disorders. This study investigated the association between a personal history and a family history of autoimmune disease and the risk of developing attention-deficit/hyperactivity disorder (ADHD).

METHOD

A cohort was formed of all singletons born in Denmark from 1990 to 2007, resulting in a study population of 983,680 individuals followed from 1995 to 2012. Information on autoimmune diseases was obtained from the Danish National Hospital Register. Individuals with ADHD were identified through the Danish National Hospital Register and the Danish Psychiatric Central Register.

RESULTS

In total, 23,645 children were diagnosed with ADHD during the study period. Autoimmune disease in the individual was associated with an increased risk of ADHD by an incidence rate ratio of 1.24 (95% CI 1.10-1.40). The primary analyses associated maternal autoimmune disease with ADHD in the offspring (incidence rate ratio 1.12, 95% CI 1.06-1.19), whereas a paternal history of autoimmune diseases was not significantly associated with ADHD in the offspring. In exploratory analyses, an increased risk of ADHD was observed for children with a family history of thyrotoxicosis, type 1 diabetes, autoimmune hepatitis, psoriasis, and ankylosing spondylitis.

CONCLUSION

A personal history and a maternal history of autoimmune disease were associated with an increased risk of ADHD. The previously reported association between type 1 diabetes and ADHD was confirmed. In addition, specific parental autoimmune diseases were associated with ADHD in offspring.

Genome-wide DNA Methylation Changes in a Mouse Model of Infection-Mediated Neurodevelopmental Disorders

BACKGROUND

Prenatal exposure to infectious or inflammatory insults increases the risk of neurodevelopmental disorders. Using a well-established mouse model of prenatal viral-like immune activation, we examined whether this pathological association involves genome-wide DNA methylation differences at single nucleotide resolution.

METHODS

Prenatal immune activation was induced by maternal treatment with the viral mimetic polyriboinosinic-polyribocytidylic acid in middle or late gestation. Following behavioral and cognitive characterization of the adult offspring (n = 12 per group), unbiased capture array bisulfite sequencing was combined with subsequent matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and quantitative real-time polymerase chain reaction analyses to quantify DNA methylation changes and transcriptional abnormalities in the medial prefrontal cortex of immune-challenged and control offspring. Gene ontology term enrichment analysis was used to explore shared functional pathways of genes with differential DNA methylation.

RESULTS

Adult offspring of immune-challenged mothers displayed hyper- and hypomethylated CpGs at numerous loci and at distinct genomic regions, including genes relevant for gamma-aminobutyric acidergic differentiation and signaling (e.g., Dlx1, Lhx5, Lhx8), Wnt signaling (Wnt3, Wnt8a, Wnt7b), and neural development (e.g., Efnb3, Mid1, Nlgn1, Nrxn2). Altered DNA methylation was associated with transcriptional changes of the corresponding genes. The epigenetic and transcriptional effects were dependent on the offspring's age and were markedly influenced by the precise timing of prenatal immune activation.

CONCLUSIONS

Prenatal viral-like immune activation is capable of inducing stable DNA methylation changes in the medial prefrontal cortex. These long-term epigenetic modifications are a plausible mechanism underlying the disruption of prefrontal gene transcription and behavioral functions in subjects with prenatal infectious histories.

Gestational maternal C--reactive protein and risk of bipolar disorder among young individuals in a Nationwide Birth Cohort

OBJECTIVES

C-reactive protein (CRP) is a well-established general marker of inflammation from both infectious and noninfectious exposures. Previous studies have shown that maternal CRP is associated with an increased risk of autism and schizophrenia. The aim of this study was to examine the association between early to mid-gestational serum CRP levels, prospectively assayed in maternal sera, and the risk of bipolar disorder (BPD).

METHODS

This study is derived from the Finnish Prenatal Study of Bipolar Disorder (FIPS-B), based on a nested case-control study design. A total of 378 BPD cases and 378 controls, matched on date of birth and sex, with available maternal sera were identified from Finnish nationwide registers. Maternal CRP levels were assessed using a latex immunoassay from archived maternal serum specimens, collected primarily during the first and second trimesters of pregnancy.

RESULTS

Increasing maternal CRP, examined as a continuous variable, was not associated with BPD (OR=0.92, 95% CI: 0.81-1.05, p=0.24). The result did not change appreciably following adjustment for potential confounders. There were no associations between CRP in the highest quintile or decile, compared with their respective reference groups, and BPD.

LIMITATIONS

The limitations of the study include: relative young age of the cohort and availability only of a single marker of inflammation.

CONCLUSIONS

In contrast to previous findings on schizophrenia and autism, gestational maternal serum CRP levels were not associated with an increased risk of BPD. It is likely that maternal inflammation may be an additional factor that differentiates schizophrenia from BPD.

Serum levels of Glial fibrillary acidic protein in Chinese children with autism spectrum disorders

OBJECTIVE

Glial fibrillary acidic protein (GFAP) has been studied in many neurological diseases. The purpose of this study is to investigate the potential role of GFAP in Chinese children with autism spectrum disorders (ASD) by measuring serum circulating levels of GFAP and comparing them with age and gender-matched typical development children.

METHODS

A total of one hundred and fifty 2-6 years old Chinese children (75 confirmed autism cases and 75 their age-gender matched typical development children) participated in this study. Serum levels of GFAP were assayed with enzyme-linked immunosorbent assay methods, and severity of ASD was evaluated with the Childhood Autism Rating Scale (CARS) Score.

RESULTS

The results indicated that the mean serum GFAP level was significantly (P<0.001) higher in autistic children as compared to controls (1.71±0.53ng/ml vs. 0.99±0.25ng/ml). There was a significant positive association between serum GFAP levels and CARS scores (r [Pearson]=0.390, P=0.001). Based on the Receiver operating characteristic (ROC) curve, the optimal cut-off value of serum GFAP levels as an indicator for auxiliary diagnosis of autism was projected to be 1.28ng/ml which yielded a sensitivity of 77.3% and a specificity of 88.4%, the area under the curve was 0.895(95%CI, 0.844-0.947). Further, an increased risk of ASD was associated with GFAP levels >1.28ng/ml (adjusted OR 9.88, 95% CI: 3.32-17.82) in the multivariate logistic analysis model.

CONCLUSION

The data indicates that serum GFAP levels may be associated with severity of ASD among Chinese children, suggesting the hypothesis that increased serum levels of GFAP could be implicated in the pathophysiology of autism in Chinese children.

The immune system as a novel regulator of sex differences in brain and behavioral development

Sexual differentiation of the brain occurs early in life as a result of sex-typical hormone action and sex chromosome effects. Immunocompetent cells are being recognized as underappreciated regulators of sex differences in brain and behavioral development, including microglia, astrocytes, and possibly other less well studied cell types, including T cells and mast cells. Immunocompetent cells in the brain are responsive to steroid hormones, but their role in sex-specific brain development is an emerging field of interest. This Review presents a summary of what is currently known about sex differences in the number, morphology, and signaling profile of immune cells in the developing brain and their role in the early-life programming of sex differences in brain and behavior. We review what is currently known about sex differences in the response to early-life perturbations, including stress, inflammation, diet, and environmental pollutants. We also discuss how and why understanding sex differences in the developing neuroimmune environment may provide insight into understanding the etiology of several neurodevelopmental disorders. This Review also highlights what remains to be discovered in this emerging field of developmental neuroimmunology and underscores the importance of filling in these knowledge gaps. © 2016 Wiley Periodicals, Inc.

Maternal Depressive Symptoms During and After Pregnancy and Psychiatric Problems in Children

OBJECTIVE

Maternal depressive symptoms during pregnancy are associated with increased risk of psychiatric problems in children. A more precise understanding of the timing of the symptoms during pregnancy and their independence of other prenatal and postnatal factors in predicting child psychopathology risk is needed. We examined whether maternal depressive symptoms during pregnancy predict child psychiatric problems, whether these associations are trimester- or gestational-week-specific and/or independent of pregnancy disorders, and whether maternal depressive symptoms after pregnancy mediate or add to the prenatal effects.

METHOD

The study sample comprised 2,296 women and their children born in Finland between 2006-2010, participating in the prospective pregnancy cohort study Prediction and Prevention of Preeclampsia and Intrauterine Growth Restriction (PREDO) and followed up from 1.9 to 5.9 years of age. The women completed the Center for Epidemiologic Studies Depression Scale biweekly between gestational weeks+days 12+0/13+6 and 38+0/39+6 or delivery. In the follow-up, they completed the Beck Depression Inventory-II and Child Behavior Checklist 1½-5.

RESULTS

Maternal depressive symptoms during pregnancy predicted significantly higher internalizing (0.28 SD unit per SD unit increase [95% CI = 0.24-0.32]), externalizing (0.26 [0.23-0.30]), and total problems (0.31 [0.27-0.35]) in children. These associations were nonspecific to gestational week and hence pregnancy trimester, independent of pregnancy disorders, and independent of, although partially mediated by, maternal depressive symptoms after pregnancy. Psychiatric problems were greatest in children whose mothers reported clinically significant depressive symptoms across pregnancy trimesters and during and after pregnancy.

CONCLUSION

Maternal depressive symptoms during pregnancy predict increased psychiatric problems in young children. Preventive interventions from early pregnancy onward may benefit offspring mental health.

The Role of the Immune System in Autism Spectrum Disorder

Autism is a neurodevelopmental disorder characterized by deficits in communication and social skills as well as repetitive and stereotypical behaviors. While much effort has focused on the identification of genes associated with autism, research emerging within the past two decades suggests that immune dysfunction is a viable risk factor contributing to the neurodevelopmental deficits observed in autism spectrum disorders (ASD). Further, it is the heterogeneity within this disorder that has brought to light much of the current thinking regarding the subphenotypes within ASD and how the immune system is associated with these distinctions. This review will focus on the two main axes of immune involvement in ASD, namely dysfunction in the prenatal and postnatal periods. During gestation, prenatal insults including maternal infection and subsequent immunological activation may increase the risk of autism in the child. Similarly, the presence of maternally derived anti-brain autoantibodies found in ~20% of mothers whose children are at risk for developing autism has defined an additional subphenotype of ASD. The postnatal environment, on the other hand, is characterized by related but distinct profiles of immune dysregulation, inflammation, and endogenous autoantibodies that all persist within the affected individual. Further definition of the role of immune dysregulation in ASD thus necessitates a deeper understanding of the interaction between both maternal and child immune systems, and the role they have in diagnosis and treatment.

Prenatal exposure to very severe maternal obesity is associated with adverse neuropsychiatric outcomes in children

BACKGROUND

Prenatal maternal obesity has been linked to adverse childhood neuropsychiatric outcomes, including increased symptoms of attention deficit hyperactivity disorder (ADHD), internalizing and externalizing problems, affective disorders and neurodevelopmental problems but few studies have studied neuropsychiatric outcomes among offspring born to very severely obese women or assessed potential familial confounding by maternal psychological distress.

METHOD

We evaluated neuropsychiatric symptoms in 112 children aged 3-5 years whose mothers had participated in a longitudinal study of obesity in pregnancy (50 very severe obesity, BMI ⩾40 kg/m2, obese class III and 62 lean, BMI 18.5-25 kg/m2). The mothers completed the Conners' Hyperactivity Scale, Early Symptomatic Syndrome Eliciting Neurodevelopmental Clinical Examination Questionnaire (ESSENCE-Q), Child's Sleep Habits Questionnaire (CSHQ), Strengths and Difficulties Questionnaire (SDQ), and Child Behavior Checklist (CBCL) to assess child neuropsychiatric symptoms. Covariates included child's sex, age, birthweight, gestational age, socioeconomic deprivation levels, maternal age, parity, smoking status during pregnancy, gestational diabetes and maternal concurrent symptoms of anxiety and depression assessed using State Anxiety of Spielberger State-Trait Anxiety Index (STAI) and General Health Questionnaire (GHQ), respectively.

RESULTS

Children exposed to prenatal maternal very severe obesity had significantly higher scores in the Conners' Hyperactivity Scale; ESSENCE-Q; total sleep problems in CSHQ; hyperactivity, conduct problems and total difficulties scales of the SDQ; higher externalizing and total problems, anxious/depressed, aggressive behaviour and other problem syndrome scores and higher DSM-oriented affective, anxiety and ADHD problems in CBCL. Prenatal maternal very severe obesity remained a significant predictor of child neuropsychiatric problems across multiple scales independent of demographic factors, prenatal factors and maternal concurrent symptoms of anxiety and depression.

CONCLUSIONS

Prenatal maternal very severe obesity is a strong predictor of increased neuropsychiatric problems in early childhood.

Transgenerational transmission and modification of pathological traits induced by prenatal immune activation

Prenatal exposure to infectious or inflammatory insults is increasingly recognized to contribute to the etiology of psychiatric disorders with neurodevelopmental components, including schizophrenia, autism and bipolar disorder. It remains unknown, however, if such immune-mediated brain anomalies can be transmitted to subsequent generations. Using an established mouse model of prenatal immune activation by the viral mimetic poly(I:C), we show that reduced sociability and increased cued fear expression are similarly present in the first- and second-generation offspring of immune-challenged ancestors. We further demonstrate that sensorimotor gating impairments are confined to the direct descendants of infected mothers, whereas increased behavioral despair emerges as a novel phenotype in the second generation. These transgenerational effects are mediated via the paternal lineage and are stable until the third generation, demonstrating transgenerational non-genetic inheritance of pathological traits following in-utero immune activation. Next-generation sequencing further demonstrated unique and overlapping genome-wide transcriptional changes in first- and second-generation offspring of immune-challenged ancestors. These transcriptional effects mirror the transgenerational effects on behavior, showing that prenatal immune activation leads to a transgenerational transmission (presence of similar phenotypes across generations) and modification (presence of distinct phenotypes across generations) of pathological traits. Together, our study demonstrates for, we believe, the first time that prenatal immune activation can negatively affect brain and behavioral functions in multiple generations. These findings thus highlight a novel pathological aspect of this early-life adversity in shaping disease risk across generations.

Integrative analysis of genetic data sets reveals a shared innate immune component in autism spectrum disorder and its co-morbidities

BACKGROUND

Autism spectrum disorder (ASD) is a common neurodevelopmental disorder that tends to co-occur with other diseases, including asthma, inflammatory bowel disease, infections, cerebral palsy, dilated cardiomyopathy, muscular dystrophy, and schizophrenia. However, the molecular basis of this co-occurrence, and whether it is due to a shared component that influences both pathophysiology and environmental triggering of illness, has not been elucidated. To address this, we deploy a three-tiered transcriptomic meta-analysis that functions at the gene, pathway, and disease levels across ASD and its co-morbidities.

RESULTS

Our analysis reveals a novel shared innate immune component between ASD and all but three of its co-morbidities that were examined. In particular, we find that the Toll-like receptor signaling and the chemokine signaling pathways, which are key pathways in the innate immune response, have the highest shared statistical significance. Moreover, the disease genes that overlap these two innate immunity pathways can be used to classify the cases of ASD and its co-morbidities vs. controls with at least 70 % accuracy.

CONCLUSIONS

This finding suggests that a neuropsychiatric condition and the majority of its non-brain-related co-morbidities share a dysregulated signal that serves as not only a common genetic basis for the diseases but also as a link to environmental triggers. It also raises the possibility that treatment and/or prophylaxis used for disorders of innate immunity may be successfully used for ASD patients with immune-related phenotypes.

Maternal immune activation induces GAD1 and GAD2 promoter remodeling in the offspring prefrontal cortex

Maternal infection during pregnancy increases the risk of neurodevelopmental disorders in the offspring. In addition to its influence on other neuronal systems, this early-life environmental adversity has been shown to negatively affect cortical γ-aminobutyric acid (GABA) functions in adult life, including impaired prefrontal expression of enzymes required for GABA synthesis. The underlying molecular processes, however, remain largely unknown. In the present study, we explored whether epigenetic modifications represent a mechanism whereby maternal infection during pregnancy can induce such GABAergic impairments in the offspring. We used an established mouse model of prenatal immune challenge that is based on maternal treatment with the viral mimetic poly(I:C). We found that prenatal immune activation increased prefrontal levels of 5-methylated cytosines (5mC) and 5-hydroxymethylated cytosines (5hmC) in the promoter region of GAD1, which encodes the 67-kDa isoform of the GABA-synthesising enzyme glutamic acid decarboxylase (GAD67). The early-life challenge also increased 5mC levels at the promoter region of GAD2, which encodes the 65-kDa GAD isoform (GAD65). These effects were accompanied by elevated GAD1 and GAD2 promoter binding of methyl CpG-binding protein 2 (MeCP2) and by reduced GAD67 and GAD65 mRNA expression. Moreover, the epigenetic modifications at the GAD1 promoter correlated with prenatal infection-induced impairments in working memory and social interaction. Our study thus highlights that hypermethylation of GAD1 and GAD2 promoters may be an important molecular mechanism linking prenatal infection to presynaptic GABAergic impairments and associated behavioral and cognitive abnormalities in the offspring.

Maternal infection during pregnancy and risk of autism spectrum disorders: A systematic review and meta-analysis

Conflicting evidence exists with regard to the relationship between maternal infection during pregnancy and the risk of autism spectrum disorder (ASD) in offspring. The aim of this meta-analysis was to systematically assess this relationship. To identify relevant studies, we conducted systematic searches in PubMed and Embase of scientific articles published through March 2016. Random-effects models were adopted to estimate overall relative risk. A total of 15 studies (2 cohort and 13 case-control studies) involving more than 40,000 ASD cases were included in our meta-analysis. Our results showed that maternal infection during pregnancy was associated with an increased risk of ASD in offspring (OR=1.13, 95% confidence interval (CI): 1.03-1.23), particularly among those requiring hospitalization (OR=1.30, 95% CI: 1.14-1.50). Subgroup analyses suggested that risk may be modulated by the type of infectious agent, time of infectious exposure, and site of infection. These findings indicate that maternal infection during pregnancy increases the risk of ASD in offspring. Possible mechanisms may include direct effects of pathogens and, more indirectly, the effects of inflammatory responses on the developing brain.

Immuno-psychiatry: an agenda for clinical practice and innovative research

BACKGROUND

The diagnostic scheme for psychiatric disorders is currently based purely on descriptive nomenclature given that biomarkers subtypes and clearly defined causal mechanisms are lacking for the vast majority of disorders. The emerging field of "immuno-psychiatry" has the potential to widen the exploration of a mechanism-based nosology, possibly leading to the discovery of more effective personalised treatment strategies.

DISCUSSION

Disturbances in immuno-inflammatory and related systems have been implicated in the aetiology, pathophysiology, phenomenology and comorbidity of several psychiatric disorders, including major mood disorders and schizophrenia. A fundamental challenge in their clinical management is to identify bio-signatures that might indicate risk, state, trait, prognosis or theragnosis. Here, we provide the rationale for a clinical and research agenda to refine future clinical practice and conceptual views, and to delineate pathways toward innovative treatment discovery.

CONCLUSION

The development of bio-signatures will allow clinicians to tailor interventions to the abovementioned biomarker subtypes - a major translational goal for research in this field.

Levels of C-reactive protein (CRP) in elderly patients with unipolar depression - case control analysis

AIM

C-reactive protein (CRP) is the major acute-phase plasma protein. Studies show that patients with depression have elevated levels of CRP. The aim of the study was to determine differences in CRP serum level in elderly patients with unipolar depression (DEP) compared with non-depressed elderly patients (nonDEP) using case-control analysis.

METHODS

Serum level of CRP was measured in 404 (DEP: n = 202, nonDEP: n = 202) Caucasian inpatients aged ≥60 (350 women, 86.7%; mean age = 76.7 years).

RESULTS

Mean CRP level in the study groups was: DEP 2.67 ± 2.56 mg/dL, nonDEP 2.41 ± 2.19 mg/dL, the difference was not significant (p = 0.96). The overall rate of being above the high level of CRP (set at 3.0 mg/L) was 33.2% for DEP and 29.2% for nonDEP groups (p = 0.39). It was also found that, in the whole study group, CRP level was not correlated with age (p = 0.10).

CONCLUSIONS

Elderly patients with depression have no increased CRP levels. A high percentage (∼30%) of all subjects had a CRP level >3 mg/L, which is the cut-off point for increased cardiovascular risk.

A Critical Period in Purkinje Cell Development Is Mediated by Local Estradiol Synthesis, Disrupted by Inflammation, and Has Enduring Consequences Only for Males

Identifying and understanding critical periods in brain development is essential to decoding the long-term impact of widespread, poorly defined, and frequently occurring insults such as inflammation. Using the laboratory rat Rattus norvegicus, we have discovered a narrowly constrained critical period in Purkinje neuron development subject to dysregulation by inflammation. The onset and offset of heightened vulnerability are attributed to a tightly orchestrated gene expression profile present only during the second postnatal week and not the first or third weeks. Genes expressed during this time code for enzymes and receptors which are critical not only for prostaglandin production and activity but also for estradiol production via the aromatase enzyme and estradiol action via the α isoform of the estrogen receptor. The two synthetic pathways are connected by prostaglandin E2 (PGE2) activation of the aromatase enzyme, as we reported previously (Dean et al., 2012b) and confirm here. Dysregulation of the PGE2-estradiol pathway during the second week by treatment with PGE2 or lipopolysaccharides produces enduring consequences as a result of reduced growth of Purkinje dendritic trees and impaired juvenile social play behavior, but only in males. The deleterious consequences of inflammation locally in the cerebellum are prevented by peripheral treatment with the cyclooxygenase inhibitor nimesulide or the aromatase inhibitor formestane. These findings highlight a novel regulatory pathway that creates a critical period in brain development vulnerable to dysregulation by inflammation.

SIGNIFICANCE STATEMENT

The cerebellum is increasingly appreciated for its role in social, emotional, and cognitive behaviors. It is consistently and severely affected in neuropsychiatric disorders originating during development, such as autism spectrum disorder and schizophrenia. We have identified a critical period in rat development during the second week of life that is dysregulated by inflammatory insults. An intrinsic program of gene expression determines the critical period. The enduring consequences of inflammation during the second postnatal week are stunted dendrites of the cerebellum's principal neurons, Purkinje cells, and impairments in later social behavior. These changes are not evident if inflammation occurs during the first or third week, highlighting the importance of fine-grained analyses of developmental processes and the factors that influence them.

Genetic Syndromes, Maternal Diseases and Antenatal Factors Associated with Autism Spectrum Disorders (ASD)

Autism spectrum disorder (ASD) affecting about 1% of all children is associated, in addition to complex genetic factors, with a variety of prenatal, perinatal, and postnatal etiologies. In addition, ASD is often an important clinical presentation of some well-known genetic syndromes in human. We discuss these syndromes as well as the role of the more important prenatal factors affecting the fetus throughout pregnancy which may also be associated with ASD. Among the genetic disorders we find Fragile X, Rett syndrome, tuberous sclerosis, Timothy syndrome, Phelan-McDermid syndrome, Hamartoma tumor syndrome, Prader-Willi and Angelman syndromes, and a few others. Among the maternal diseases in pregnancy associated with ASD are diabetes mellitus (PGDM and/or GDM), some maternal autoimmune diseases like antiphospholipid syndrome (APLS) with anti-β2GP1 IgG antibodies and thyroid disease with anti-thyroid peroxidase (TPO) antibodies, preeclampsia and some other autoimmune diseases with IgG antibodies that might affect fetal brain development. Other related factors are maternal infections (rubella and CMV with fetal brain injuries, and possibly Influenza with fever), prolonged fever and maternal inflammation, especially with changes in a variety of inflammatory cytokines and antibodies that cross the placenta and affect the fetal brain. Among the drugs are valproic acid, thalidomide, misoprostol, and possibly SSRIs. β2-adrenergic receptor agonists and paracetamol have also lately been associated with increased rate of ASD but the data is too preliminary and inconclusive. Associations were also described with ethanol, cocaine, and possibly heavy metals, heavy smoking, and folic acid deficiency. Recent studies show that heavy exposure to pesticides and air pollution, especially particulate matter < 2.5 and 10 μm in diameter (PM2.5 and PM10) during pregnancy is also associated with ASD. Finally, we have to remember that many of the associations mentioned in this review are only partially proven, and not all are "clean" of different confounding factors. The associations described in this review emphasize again how little we know about the etiology and pathogenesis of ASD. It is obvious that we need more epidemiologic data to establish many of these associations, but if proven, they might be promising avenues for prevention.

Prenatal immune activation causes hippocampal synaptic deficits in the absence of overt microglia anomalies

Prenatal exposure to infectious or inflammatory insults can increase the risk of developing neuropsychiatric disorder in later life, including schizophrenia, bipolar disorder, and autism. These brain disorders are also characterized by pre- and postsynaptic deficits. Using a well-established mouse model of maternal exposure to the viral mimetic polyriboinosinic-polyribocytidilic acid [poly(I:C)], we examined whether prenatal immune activation might cause synaptic deficits in the hippocampal formation of pubescent and adult offspring. Based on the widely appreciated role of microglia in synaptic pruning, we further explored possible associations between synaptic deficits and microglia anomalies in offspring of poly(I:C)-exposed and control mothers. We found that prenatal immune activation induced an adult onset of presynaptic hippocampal deficits (as evaluated by synaptophysin and bassoon density). The early-life insult further caused postsynaptic hippocampal deficits in pubescence (as evaluated by PSD95 and SynGAP density), some of which persisted into adulthood. In contrast, prenatal immune activation did not change microglia (or astrocyte) density, nor did it alter their activation phenotypes. The prenatal manipulation did also not cause signs of persistent systemic inflammation. Despite the absence of overt glial anomalies or systemic inflammation, adult offspring exposed to prenatal immune activation displayed increased hippocampal IL-1β levels. Taken together, our findings demonstrate that age-dependent synaptic deficits and abnormal pro-inflammatory cytokine expression can occur during postnatal brain maturation in the absence of microglial anomalies or systemic inflammation.

Prenatal and Newborn Immunoglobulin Levels from Mother-Child Pairs and Risk of Autism Spectrum Disorders

Background: An etiological role for immune factors operating during early brain development in children with autism spectrum disorders (ASD) has not yet been established. A major obstacle has been the lack of early biologic specimens that can be linked to later diagnosis. In a prior study, we found lower risk of ASD associated with higher levels of maternally-derived total IgG and Toxoplasmosis gondii (Toxo) IgG in newborn blood spot specimens from children later diagnosed with ASD compared to population controls.

Methods: We obtained maternal mid-gestational serum specimens and newborn screening blood spots from the California Genetics Disease Screening Program (GDSP) for linked mother-baby pairs for 84 children with ASD and 49 children with developmental delay but not ASD (DD) identified from California Department of Developmental Services records and for 159 population controls sampled from birth certificates.Immunoglobulin levels in maternal and newborn specimens were measured by solid phase immunoassays and analyzed in logistic regression models for total IgG, total IgM, and Toxo IgG, and, for maternal specimens only, Toxo IgM. Correlations between maternal and newborn ranked values were evaluated.

Results: In both maternal and newborn specimens, we found significantly lower risk of ASD associated with higher levels of Toxo IgG. In addition, point estimates for all comparisons were < 1.0 suggesting an overall pattern of lower immunoglobulin levels associated with higher ASD risk but most did not reach statistical significance. We did not find differences in maternal or newborn specimens comparing children with DD to controls.

Discussion: These results are consistent with evidence from our prior study and other published reports indicating that immune factors during early neurodevelopment may be etiologically relevant to ASD. Lowered immunoglobulin levels may represent suboptimal function of the maternal immune system or reduced maternal exposure to common infectious agents.

Conclusion: Patterns seen in these selected immunoglobulins may provide clues to mechanisms of early abnormalities in neurodevelopment contributing to ASD. We recommend further study of immunoglobulin profiles in larger samples of linked mother-baby pairs to evaluate possible etiologic relevance.

Neonatal inflammatory pain and systemic inflammatory responses as possible environmental factors in the development of autism spectrum disorder of juvenile rats

Background

Autism spectrum disorder (ASD) affects many children and juveniles. The pathogenesis of ASD is not well understood. Environmental factors may play important roles in the development of ASD. We examined a possible relationship of inflammatory pain in neonates and the development of ASD in juveniles.

Methods

Acute inflammation pain was induced by 5 % formalin (5 μl/day) subcutaneous injection into two hindpaws of postnatal day 3 to 5 (P3–P5) rat pups. Western blot, immunohistochemical, and behavioral examinations were performed at different time points after the insult.

Results

Formalin injection caused acute and chronic inflammatory responses including transient local edema, increased levels of inflammatory cytokines, TNF-α, and IL-1β in the blood as well as in the brain, and increased microglia in the brain. One day after the pain insult, there was significant cell death in the cortex and hippocampus. Two weeks later, although the hindpaw local reaction subsided, impaired axonal growth and demyelization were seen in the brain of P21 juvenile rats. The number of bromodeoxyuridine (BrdU) and doublecortin (DCX) double-positive cells in the hippocampal dentate gyrus of P21 rats was significantly lower than that in controls, indicating reduced neurogenesis. In the P21 rat’s brain of the formalin group, the expression of autism-related gene neurexin 1 (NRXN1), fragile X mental retardation 1 (FMR1), and oxytocin was significantly downregulated, consistent with the gene alteration in ASD. Juvenile rats in the formalin group showed hyperalgesia, repetitive behaviors, abnormal locomotion, sleep disorder, and distinct deficits in social memory and social activities. These alterations in neuroinflammatory reactions, gene expression, and behaviors were more evident in male than in female rats. Importantly, an anti-inflammation treatment using indomethacin (10 mg/kg, i.p.) at the time of formalin injections suppressed inflammatory responses and neuronal cell death and prevented alterations in ASD-related genes and the development of abnormal behaviors.

Conclusions

These novel observations indicate that severe inflammatory pain in neonates and persistent inflammatory reactions may predispose premature infants to development delays and psychiatric disorders including ASD. The prevention of pain stimuli and prompt treatments of inflammation during development appear vitally important in disrupting possible evolution of ASD syndromes.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-016-0575-x) contains supplementary material, which is available to authorized users.

Vertical transmission of Zika virus targeting the radial glial cells affects cortex development of offspring mice

The recent Zika virus (ZIKV) epidemic in Latin America coincided with a marked increase in microcephaly in newborns. However, the causal link between maternal ZIKV infection and malformation of the fetal brain has not been firmly established. Here we show a vertical transmission of ZIKV in mice and a marked effect on fetal brain development. We found that intraperitoneal (i.p.) injection of a contemporary ZIKV strain in pregnant mice led to the infection of radial glia cells (RGs) of dorsal ventricular zone of the fetuses, the primary neural progenitors responsible for cortex development, and caused a marked reduction of these cortex founder cells in the fetuses. Interestingly, the infected fetal mice exhibited a reduced cavity of lateral ventricles and a discernable decrease in surface areas of the cortex. This study thus supports the conclusion that vertically transmitted ZIKV affects fetal brain development and provides a valuable animal model for the evaluation of potential therapeutic or preventative strategies.

Using human brain imaging studies as a guide toward animal models of schizophrenia

Schizophrenia is a heterogeneous and poorly understood mental disorder that is presently defined solely by its behavioral symptoms. Advances in genetic, epidemiological and brain imaging techniques in the past half century, however, have significantly advanced our understanding of the underlying biology of the disorder. In spite of these advances clinical research remains limited in its power to establish the causal relationships that link etiology with pathophysiology and symptoms. In this context, animal models provide an important tool for causally testing hypotheses about biological processes postulated to be disrupted in the disorder. While animal models can exploit a variety of entry points toward the study of schizophrenia, here we describe an approach that seeks to closely approximate functional alterations observed with brain imaging techniques in patients. By modeling these intermediate pathophysiological alterations in animals, this approach offers an opportunity to (1) tightly link a single functional brain abnormality with its behavioral consequences, and (2) to determine whether a single pathophysiology can causally produce alterations in other brain areas that have been described in patients. In this review we first summarize a selection of well-replicated biological abnormalities described in the schizophrenia literature. We then provide examples of animal models that were studied in the context of patient imaging findings describing enhanced striatal dopamine D2 receptor function, alterations in thalamo-prefrontal circuit function, and metabolic hyperfunction of the hippocampus. Lastly, we discuss the implications of findings from these animal models for our present understanding of schizophrenia, and consider key unanswered questions for future research in animal models and human patients.