Prenatal exposure to fever is associated with autism spectrum disorder in the boston birth cohort

Maternal Immune Activation and Child Brain Development: A Longitudinal Population-Based Multimodal Neuroimaging Study

BACKGROUND

Maternal immune activation (MIA) has been hypothesized to have an adverse effect on child neurodevelopment, but only a few neuroimaging studies have been performed to date, mostly in neonates. In this population-based cohort study, we investigated the association between MIA and multiple neuroimaging modalities depicting brain development from childhood to adolescence.

METHODS

We used data of mother-child pairs from the Generation R Study. To define our exposure, we measured interleukin (IL) 1β, IL-6, IL-17a, IL-23, interferon gamma, and C-reactive protein at 2 time points during pregnancy. Because levels of these 5 cytokines were highly correlated, we were able to compute a cytokine index. We used multiple brain imaging modalities as outcomes, including global and regional measures of brain morphology (structural magnetic resonance imaging, volume; n = 3295), white matter microstructure (diffusion magnetic resonance imaging, fractional anisotropy and mean diffusivity; n = 3267), and functional connectivity (functional magnetic resonance imaging, graph theory measures, and network-level connectivity; n = 2914) in the children at ages 10 and 14 years. We performed mixed effects models using child's age as a continuous time variable.

RESULTS

We found no significant effect of time on any neuroimaging outcomes in children over time, and there was no time × MIA interaction. These associations were similar for the cytokine index, C-reactive protein, and individual cytokines. We observed no evidence for differential effects of timing of prenatal MIA or child sex after multiple testing correction.

CONCLUSIONS

In this longitudinal population-based study, we found no evidence for an association between MIA and child brain development in the general population. Our findings differ from previous research in neonates that have shown structural and functional brain abnormalities after MIA.

Maternal Immune Activation and Autism in Offspring: What Is the Evidence for Causation?

The maternal immune activation hypothesis has gained attention over the past 2 decades as a potential contributor to the etiology of autism. This hypothesis posits that maternal conditions associated with inflammation during pregnancy may increase the risk of autism in offspring. Autism is highly heritable, and causal environmental contributors to autism largely remain elusive. We review studies on maternal conditions during pregnancy, all associated with some degree of systemic inflammation, namely maternal infections, autoimmunity, and high body mass index. We also review studies of inflammatory markers in biological samples collected from mothers during pregnancy or from neonates and their relationship with autism assessed in children later in life. Recent reports indicate familial clustering of autism, autoimmunity, and infections, as well as genetic correlations between autism and aspects of immune function. Given this literature, there is an apparent risk of confounding of the reported associations between inflammatory exposures and autism by familial genetic factors in both clinical and epidemiological cohort studies. We highlight recent studies that have attempted to address potential confounding to assess evidence of causal effects of inflammation during early life in autism.

Prenatal and early childhood infections requiring hospitalization and risk of neurodevelopmental disorders in offspring: a population-based birth cohort study in Taiwan

In utero and early childhood infections have been associated with an increased risk of neurodevelopmental disorders; however, the observed associations may be confounded by familial predispositions. This study examined the neurodevelopmental disorders attributable to maternal infections during pregnancy and early childhood infections during the first year of life, including autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), tic disorders, and mental retardation (MR). We performed population and sibling comparison analyses to account for unmeasured familial confounding factors. We conducted a register-based cohort study with 2,885,662 individuals (comprising 1,864,660 full siblings) born in Taiwan between 2001 and 2018 and followed up until 2021. We employed Cox regression analysis to assess the association between in utero and early childhood infections requiring hospitalization and the subsequent risk of neurodevelopmental disorders. In the population analyses, an offspring exposed to maternal infection had an increased risk for ASD (hazard ratio (HR) = 1.19, 95% confidence interval (CI): 1.13-1.26), ADHD (HR = 1.14, 95% CI: 1.11-1.18), and MR (HR = 1.21, 95% CI: 1.13-1.30). These associations attenuated toward null in the sibling analyses. Individuals exposed to early childhood infection had an increased risk for ASD (HR = 1.13, 95% CI: 1.10-1.16), ADHD (HR = 1.16, 95% CI: 1.15-1.18), tic disorders (HR = 1.12, 95% CI: 1.09-1.15), and MR (HR = 1.64, 95% CI: 1.60-1.69) in the population analyses; these associations were also significant for ASD (HR = 1.14, 95% CI: 1.07-1.21) and MR (HR = 1.52, 95% CI: 1.44-1.62) in the sibling analyses. The association between maternal infection during pregnancy and offspring neurodevelopmental risk is largely due to familial confounding factors. Conversely, infection in early childhood may be attributable to it being a sensitive period and may play a role in the subsequent risk of ASD and MR.

Socio-medical Factors Associated with Neurodevelopmental Disorders on the Kenyan Coast

Background

Neurodevelopmental disorders (NDDs) are a group of conditions with their onset during the early developmental period and include conditions such as autism, intellectual disability and attention deficit hyperactivity disorder (ADHD). Occurrence of NDDs is thought to be determined by both genetic and environmental factors, but data on the role of environmental risk factors for NDD in Africa is limited. This study investigates environmental influences on NDDs in children from Kenya. This case-control study compared children with NDDs and typically developing children from two studies on the Kenyan coast that did not overlap.

Methods and Findings

We included 172 of the study participants from the Kilifi Autism Study and 151 from the NeuroDev Study who had a diagnosis of at least one NDD and 112 and 73 with no NDD diagnosis from each study, respectively. Potential risk factors were identified using unadjusted univariable analysis and adjusted multivariable logistic regression analysis. Univariable analysis in the Kilifi Autism Study sample revealed hypoxic-ischaemic encephalopathy conferred the largest odds ratio (OR) 10.52 (95%CI 4.04 - 27.41) for NDDs, followed by medical complications during pregnancy (gestational hypertension & diabetes, eclampsia, and maternal bleeding) OR: 3.17 (95%CI 1.61 - 6.23). In the NeuroDev study sample, labour and birth complications (OR: 7.30 (2.17 - 24.61)), neonatal jaundice (OR: 5.49 (95%CI 1.61 - 18.72)) and infection during pregnancy (OR: 5.31 (1.56 - 18.11)) conferred the largest risk associated with NDDs. In the adjusted analysis, seizures before age 3 years in the Kilifi Autism study and labour and birth complications in the NeuroDev study conferred the largest increased risk. Higher parity, the child being older and delivery at home were associated with a reduced risk for NDDs.

Conclusion

Recognition of important risk factors such as labour and birth complications could guide preventative interventions, developmental screening of at-risk children and monitoring progress. Further studies examining the aetiology of NDDs in population-based samples, including investigating the interaction between genetic and environmental factors, are needed.

Food, nutrition, and autism: from soil to fork

Food and nutrition-related factors have the potential to impact development of autism spectrum disorder (ASD) and quality of life for people with ASD, but gaps in evidence exist. On 10 November 2022, Tufts University's Friedman School of Nutrition Science and Policy and Food and Nutrition Innovation Institute hosted a 1-d meeting to explore the evidence and evidence gaps regarding the relationships of food and nutrition with ASD. This meeting report summarizes the presentations and deliberations from the meeting. Topics addressed included prenatal and child dietary intake, the microbiome, obesity, food-related environmental exposures, mechanisms and biological processes linking these factors and ASD, food-related social factors, and data sources for future research. Presentations highlighted evidence for protective associations with prenatal folic acid supplementation and ASD development, increases in risk of ASD with maternal gestational obesity, and the potential for exposure to environmental contaminants in foods and food packaging to influence ASD development. The importance of the maternal and child microbiome in ASD development or ASD-related behaviors in the child was reviewed, as was the role of discrimination in leading to disparities in environmental exposures and psychosocial factors that may influence ASD. The role of child diet and high prevalence of food selectivity in children with ASD and its association with adverse outcomes were also discussed. Priority evidence gaps identified by participants include further clarifying ASD development, including biomarkers and key mechanisms; interactions among psychosocial, social, and biological determinants; interventions addressing diet, supplementation, and the microbiome to prevent and improve quality of life for people with ASD; and mechanisms of action of diet-related factors associated with ASD. Participants developed research proposals to address the priority evidence gaps. The workshop findings serve as a foundation for future prioritization of scientific research to address evidence gaps related to food, nutrition, and ASD.

Examining the relationship between autism spectrum disorder in children whose mother had labour epidural analgesia for their birth: A retrospective cohort study

BACKGROUND

Controversy exists regarding the association between autism spectrum disorder (ASD) in children whose mother had labour epidural analgesia for their birth, as the few existing investigations have reported mixed findings.

OBJECTIVE

This study aims to evaluate the possibility of an association in our heterogeneous population.

DESIGN

A retrospective population-based cohort study.

SETTING

Vaginal deliveries that took place between the years 2005 and 2017 at Soroka University Medical Center, a tertiary referral hospital in Israel, and a follow-up on the incidence of ASD in the children.

PATIENTS

A hundred and thirty-nine thousand, nine hundred and eighty-one labouring patients and their offspring.

MAIN OUTCOME MEASURES

The incidence of children diagnosed with ASD (both hospital and community-based diagnoses) was compared based on whether their mothers had received labour epidural analgesia during their labour. A Kaplan-Meier survival curve compared cumulative incidence of ASD. A Cox proportional hazards model was used to control for relevant confounders.

RESULTS

Labour epidural analgesia was administered to 33 315 women. Epidural analgesia was more common among high-risk pregnancy groups (including pregnancies complicated with diabetes mellitus, hypertensive disorders, intrauterine growth restriction, and oligohydramnios; P  < 0.001). In a Cox proportional hazards model, the association between epidural analgesia during labour and ASD in the children lost statistical significance following adjustment for confounders such as maternal age, gestational age, hypertensive disorders, diabetes mellitus, and ethnicity [adjusted hazard ratio = 1.13, 95% confidence interval (CI), 0.96 to 1.34, P  = 0.152].

CONCLUSION

In our population, after adjusting for confounders, epidural analgesia is not independently associated with autism spectrum disorder in the children. These findings enhance our knowledge regarding the safety of epidural analgesia and enable patients to make informed decisions about their pain relief techniques during labour.

Early Life Origins of Neurodevelopmental Disabilities in the Boston Birth Cohort: Research findings and future directions

Neurodevelopmental disabilities (NDD) are a group of conditions with onset in early development period and is characterized by limitations in several functional domains. Autism spectrum disorder (ASD) and Attention-Deficit Hyperactivity Disorders (ADHD), the most common NDDs, have complex etiologies and possibly multiple pathways leading up to the manifestation of these disorders. Boston Birth Cohort (BBC) is a preterm enriched birth cohort, and over the years, researchers have used the BBC dataset to study a broad spectrum of early life protective and risk factors in the context of NDDs. Broadly, some of them include: 1) nutrition (e.g. maternal folate, vitamin B12, cord folate species, selenium), 2) metabolic factors (e.g. role of maternal diabetes, obesity, branched chain amino acids and other essential amino acids), 3) lipid metabolism (e.g. maternal cholesterol), 4) immune activation and/or systematic inflammation (including maternal immune activation, inflammation of the placenta, inflammatory markers, maternal antibiotic use and acetaminophen use), and 5) other factors associated with NDDs (e.g. maternal stress, sickle cell disease). The findings from these studies are discussed in this review. BBC studies have advanced the field of NDD in the following important ways: 1) generating evidence that sheds light on new exposures, 2) furthering the existing knowledge using better methodological approaches, 3) analyzing novel mechanistic pathways on already proven relationship, and 4) advancing knowledge on the under-studied minority population in the U.S. BBC researchers are involved in ongoing efforts to characterize NDD developmental trajectories across the life stages by integrating multi-omics data (genome, epigenome, and metabolome) to gain a deeper understanding of the molecular pathways by which early life factors drive or shape the developmental trajectories of NDDs.

Maternal Influenza and Offspring Neurodevelopment

This review examines the complex interactions between maternal influenza infection, the immune system, and the neurodevelopment of the offspring. It highlights the importance of high-quality studies to clarify the association between maternal exposure to the virus and neuropsychiatric disorders in the offspring. Additionally, it emphasizes that the development of accurate animal models is vital for studying the impact of infectious diseases during pregnancy and identifying potential therapeutic targets. By drawing attention to the complex nature of these interactions, this review underscores the need for ongoing research to improve the understanding and outcomes for pregnant women and their offspring.

Environmental Influences on Individuals with Autistic Spectrum Disorders with Special Emphasis on Seasonality: An Overview

This paper offers an in-depth exploration of the intricate relationship between environmental factors and autism spectrum disorder (ASD), with a special emphasis on seasonality. It reviews existing research, providing a comprehensive summary of findings and highlighting the multifaceted dimensions of several environmental factors influencing the etiology of ASD. The discussion encompasses various elements, including birth months, maternal health, dietary choices, and vitamin D deficiency, delving into the intricate interplay of seasonality with environmental influences such as viral infections and solar radiation. The present study raises essential questions regarding the timing of environmental influences and the factors contributing to the rising prevalence of ASD. Ultimately, it underscores the need for future epidemiological research to incorporate more extensive investigations of environmental risk factors and employ advanced statistical analyses. This comprehensive overview contributes to a deeper understanding of how environmental factors, particularly seasonality, may be linked to the occurrence of ASD and its increasing prevalence, recognizing the multifaceted and diverse nature of these interactions.

Advances in the study of IL-17 in neurological diseases and mental disorders

Interleukin-17 (IL-17), a cytokine characteristically secreted by T helper 17 (Th17) cells, has attracted increasing attention in recent years because of its importance in the pathogenesis of many autoimmune or chronic inflammatory diseases. Recent studies have shown that neurological diseases and mental disorders are closely related to immune function, and varying degrees of immune dysregulation may disrupt normal expression of immune molecules at critical stages of neural development. Starting from relevant mechanisms affecting immune regulation, this article reviews the research progress of IL-17 in a selected group of neurological diseases and mental disorders (autism spectrum disorder, Alzheimer's disease, epilepsy, and depression) from the perspective of neuroinflammation and the microbiota-gut-brain axis, summarizes the commonalities, and provides a prospective outlook of target application in disease treatment.

Schmidt R, N. Pearce E. Prenatal Exposure to Per- and Polyfluoroalkyl Substances, Maternal Thyroid Dysfunction, and Child Autism Spectrum Disorder

Autism spectrum disorder (ASD), with its high economic and societal costs, is a growing public health concern whose prevalence has risen steadily over the last two decades. Although actual increased incidence versus improved diagnosis remains controversial, the increased prevalence of ASD suggests non-inherited factors as likely contributors. There is increasing epidemiologic evidence that abnormal maternal thyroid function during pregnancy is associated with increased risk of child ASD and other neurodevelopmental disorders. Prenatal exposure to endocrine-disrupting chemicals such as per- and polyfluoroalkyl substances (PFAS) is known to disrupt thyroid function and can affect early brain development; thus, thyroid dysfunction is hypothesized to mediate this relationship. The concept of a potential pathway from prenatal PFAS exposure through thyroid dysfunction to ASD etiology is not new; however, the extant literature on this topic is scant. The aim of this review is to evaluate and summarize reports with regard to potential mechanisms in this pathway.

Autism spectrum disorders pathogenesis: Toward a comprehensive model based on neuroanatomic and neurodevelopment considerations

Autism spectrum disorder (ASD) involves alterations in neural connectivity affecting cortical network organization and excitation to inhibition ratio. It is characterized by an early increase in brain volume mediated by abnormal cortical overgrowth patterns and by increases in size, spine density, and neuron population in the amygdala and surrounding nuclei. Neuronal expansion is followed by a rapid decline from adolescence to middle age. Since no known neurobiological mechanism in human postnatal life is capable of generating large excesses of frontocortical neurons, this likely occurs due to a dysregulation of layer formation and layer-specific neuronal migration during key early stages of prenatal cerebral cortex development. This leads to the dysregulation of post-natal synaptic pruning and results in a huge variety of forms and degrees of signal-over-noise discrimination losses, accounting for ASD clinical heterogeneities, including autonomic nervous system abnormalities and comorbidities. We postulate that sudden changes in environmental conditions linked to serotonin/kynurenine supply to the developing fetus, throughout the critical GW7 - GW20 (Gestational Week) developmental window, are likely to promote ASD pathogenesis during fetal brain development. This appears to be driven by discrete alterations in differentiation and patterning mechanisms arising from in utero RNA editing, favoring vulnerability outcomes over plasticity outcomes. This paper attempts to provide a comprehensive model of the pathogenesis and progression of ASD neurodevelopmental disorders.

Neuropsychiatric outcomes in offspring after fetal exposure to maternal influenza infection during pregnancy: A systematic review

Increasing evidence suggests that influenza infection in pregnancy may disrupt fetal neurodevelopment. The impact of maternal influenza infection on offspring neuropsychiatric health has not been comprehensively reviewed. We systematically reviewed comparative studies evaluating associations between maternal influenza infection and neuropsychiatric health outcomes in offspring. We searched MEDLINE, EMBASE, CINAHL, and Web of Science for articles published until January 7, 2022. Included were English studies evaluating neuropsychiatric outcomes in offspring aged > 6 months born to women with and without influenza during pregnancy, defined as clinical or laboratory-confirmed influenza illness, or being pregnant during pandemics/epidemics. Of 12,010 records screened, 42 studies were included. Heterogeneity in study design, exposures, and outcome definitions precluded meta-analyses. Four of 14 studies assessing schizophrenia reported adjusted ratio estimates from 0.5 to 8.2; most 95% CIs contained the null value; study quality was high in three of four. Two studies reported an increased risk of schizophrenia with influenza exposure any time during pregnancy (adjusted incidence rate ratio 8.2, 95% CI: 1.4-48.8; adjusted odds ratio 1.3, 95% CI: 1.2-1.5); another reported a reduced risk with first-trimester exposure (adjusted risk ratio 0.5, 95% CI: 0.3-0.9). Seven studies of autism spectrum disorder reported adjusted ratio estimates from 0.9 to 4.0; all 95% CIs included the null value; study quality was high in four. No conclusions could be drawn about the association between exposure to maternal influenza and neuropsychiatric outcomes due to the limited quantity and quality of available research. Large observational studies with long-term follow-up are required to investigate these associations.

Modern Biomarkers for Autism Spectrum Disorder: Future Directions

Autism spectrum disorder is an increasingly prevalent neurodevelopmental disorder in the world today, with an estimated 2% of the population being affected in the USA. A major complicating factor in diagnosing, treating, and understanding autism spectrum disorder is that defining the disorder is solely based on the observation of behavior. Thus, recent research has focused on identifying specific biological abnormalities in autism spectrum disorder that can provide clues to diagnosis and treatment. Biomarkers are an objective way to identify and measure biological abnormalities for diagnostic purposes as well as to measure changes resulting from treatment. This current opinion paper discusses the state of research of various biomarkers currently in development for autism spectrum disorder. The types of biomarkers identified include prenatal history, genetics, neurological including neuroimaging, neurophysiologic, and visual attention, metabolic including abnormalities in mitochondrial, folate, trans-methylation, and trans-sulfuration pathways, immune including autoantibodies and cytokine dysregulation, autonomic nervous system, and nutritional. Many of these biomarkers have promising preliminary evidence for prenatal and post-natal pre-symptomatic risk assessment, confirmation of diagnosis, subtyping, and treatment response. However, most biomarkers have not undergone validation studies and most studies do not investigate biomarkers with clinically relevant comparison groups. Although the field of biomarker research in autism spectrum disorder is promising, it appears that it is currently in the early stages of development.

The Association of Prenatal Vitamins and Folic Acid Supplement Intake with Odds of Autism Spectrum Disorder in a High-Risk Sibling Cohort, the Early Autism Risk Longitudinal Investigation (EARLI)

We examined maternal prenatal vitamin use or supplemental folic acid intake during month one of pregnancy for association with autism spectrum disorder (ASD) in the Early Autism Risk Longitudinal Investigation, an enriched-risk pregnancy cohort. Total folic acid intake was calculated from monthly prenatal vitamins, multivitamins, and other supplement reports. Clinical assessments through age 3 years classified children as ASD (n = 38) or non-ASD (n = 153). In pregnancy month one, prenatal vitamin use (59.7%) was not significantly associated with odds of ASD (OR = 0.70, 95%CI 0.32, 1.53). Sample size was limited and residual confounding was possible. Given the estimated effect sizes in this and previous work, prenatal vitamin intake during early pregnancy could be a clinically useful preventative measure for ASD.

Maternal mid-gestational and child cord blood immune signatures are strongly associated with offspring risk of ASD

Epidemiological studies and work in animal models indicate that immune activation may be a risk factor for autism spectrum disorders (ASDs). We measured levels of 60 cytokines and growth factors in 869 maternal mid-gestational (MMG) and 807 child cord blood (CB) plasma samples from 457 ASD (385 boys, 72 girls) and 497 control children (418 boys, 79 girls) from the Norwegian Autism Birth Cohort. We analyzed associations first using sex-stratified unadjusted and adjusted logistic regression models, and then employed machine learning strategies (LASSO + interactions, Random Forests, XGBoost classifiers) with cross-validation and randomly sampled test set evaluation to assess the utility of immune signatures as ASD biomarkers. We found prominent case-control differences in both boys and girls with alterations in a wide range of analytes in MMG and CB plasma including but not limited to IL1RA, TNFα, Serpin E1, VCAM1, VEGFD, EGF, CSF1, and CSF2. MMG findings were most striking, with particularly strong effect sizes in girls. Models did not change appreciably upon adjustment for maternal conditions, medication use, or emotional distress ratings. Findings were corroborated using machine learning approaches, with area under the receiver operating characteristic curve values in the test sets ranging from 0.771 to 0.965. Our results are consistent with gestational immunopathology in ASD, may provide insights into sex-specific differences, and have the potential to lead to biomarkers for early diagnosis.

What is known about neuroplacentology in fetal growth restriction and in preterm infants: A narrative review of literature

The placenta plays a fundamental role during pregnancy for fetal growth and development. A suboptimal placental function may result in severe consequences during the infant's first years of life. In recent years, a new field known as neuroplacentology has emerged and it focuses on the role of the placenta in fetal and neonatal brain development. Because of the limited data, our aim was to provide a narrative review of the most recent knowledge about the relation between placental lesions and fetal and newborn neurological development. Papers published online from 2000 until February 2022 were taken into consideration and particular attention was given to articles in which placental lesions were related to neonatal morbidity and short-term and long-term neurological outcome. Most research regarding the role of placental lesions in neurodevelopment has been conducted on fetal growth restriction and preterm infants. Principal neurological outcomes investigated were periventricular leukomalacia, intraventricular hemorrhages, neonatal encephalopathy and autism spectrum disorder. No consequences in motor development were found. All the considered studies agree about the crucial role played by placenta in fetal and neonatal neurological development and outcome. However, the causal mechanisms remain largely unknown. Knowledge on the pathophysiological mechanisms and on placenta-related risks for neurological problems may provide clues for early interventions aiming to improve neurological outcomes, especially among pediatricians and child psychiatrists.

Paracetamol use during pregnancy - a call for precautionary action

Paracetamol (N-acetyl-p-aminophenol (APAP), otherwise known as acetaminophen) is the active ingredient in more than 600 medications used to relieve mild to moderate pain and reduce fever. APAP is widely used by pregnant women as governmental agencies, including the FDA and EMA, have long considered APAP appropriate for use during pregnancy when used as directed. However, increasing experimental and epidemiological research suggests that prenatal exposure to APAP might alter fetal development, which could increase the risks of some neurodevelopmental, reproductive and urogenital disorders. Here we summarize this evidence and call for precautionary action through a focused research effort and by increasing awareness among health professionals and pregnant women. APAP is an important medication and alternatives for treatment of high fever and severe pain are limited. We recommend that pregnant women should be cautioned at the beginning of pregnancy to: forego APAP unless its use is medically indicated; consult with a physician or pharmacist if they are uncertain whether use is indicated and before using on a long-term basis; and minimize exposure by using the lowest effective dose for the shortest possible time. We suggest specific actions to implement these recommendations. This Consensus Statement reflects our concerns and is currently supported by 91 scientists, clinicians and public health professionals from across the globe.

Paracetamol (Acetaminophen) and the Developing Brain

Paracetamol is commonly used to treat fever and pain in pregnant women, but there are growing concerns that this may cause attention deficit hyperactivity disorder and autism spectrum disorder in the offspring. A growing number of epidemiological studies suggests that relative risks for these disorders increase by an average of about 25% following intrauterine paracetamol exposure. The data analyzed point to a dose-effect relationship but cannot fully account for unmeasured confounders, notably indication and genetic transmission. Only few experimental investigations have addressed this issue. Altered behavior has been demonstrated in offspring of paracetamol-gavaged pregnant rats, and paracetamol given at or prior to day 10 of life to newborn mice resulted in altered locomotor activity in response to a novel home environment in adulthood and blunted the analgesic effect of paracetamol given to adult animals. The molecular mechanisms that might mediate these effects are unknown. Paracetamol has diverse pharmacologic actions. It reduces prostaglandin formation via competitive inhibition of the peroxidase moiety of prostaglandin H2 synthase, while its metabolite N-arachidonoyl-phenolamine activates transient vanilloid-subtype 1 receptors and interferes with cannabinoid receptor signaling. The metabolite N-acetyl-p-benzo-quinone-imine, which is pivotal for liver damage after overdosing, exerts oxidative stress and depletes glutathione in the brain already at dosages below the hepatic toxicity threshold. Given the widespread use of paracetamol during pregnancy and the lack of safe alternatives, its impact on the developing brain deserves further investigation.

Gut Reactions: How Far Are We from Understanding and Manipulating the Microbiota Complexity and the Interaction with Its Host? Lessons from Autism Spectrum Disorder Studies

Autism is a group of neurodevelopmental disorders, characterized by early onset difficulties in social communication and restricted, repetitive behaviors and interests. It is characterized by familial aggregation, suggesting that genetic factors play a role in disease development, in addition to developmentally early environmental factors. Here, we review the role of the gut microbiome in autism, as it has been characterized in case-control studies. We discuss how methodological differences may have led to inconclusive or contradictory results, even though a disproportion between harmful and beneficial bacteria is generally described in autism. Furthermore, we review the studies concerning the effects of gut microbial-based and dietary interventions on autism symptoms. Also, in this case, the results are not comparable due to the lack of standardized methods. Therefore, autism-specific microbiome signatures and, consequently, possible microbiome-oriented interventions are far from being recognized. We argue that a multi-omic longitudinal implementation may be useful to study metabolic changes connected to microbiome changes.

Pregnant Mothers' Medical Claims and Associated Risk of Their Children being Diagnosed with Autism Spectrum Disorder

A retrospective analysis of administrative claims containing a diverse mixture of ages, ethnicities, and geographical regions across the United States was conducted in order to identify medical events that occur during pregnancy and are associated with autism spectrum disorder (ASD). The dataset used in this study is comprised of 123,824 pregnancies of which 1265 resulted in the child being diagnosed with ASD during the first five years of life. Logistic regression analysis revealed significant relationships between several maternal medical claims, made during her pregnancy and segmented by trimester, and the child's diagnosis of ASD. Having a biological sibling with ASD, maternal use of antidepressant medication and psychiatry services as well as non-pregnancy related claims such hospital visits, surgical procedures, and radiology exposure were related to an increased risk of ASD regardless of trimester. Urinary tract infections during the first trimester and preterm delivery during the second trimester were also related to an increased risk of ASD. Preventative and obstetrical care were associated with a decreased risk for ASD. A better understanding of the medical factors that increase the risk of having a child with ASD can lead to strategies to decrease risk or identify those children who require increased surveillance for the development of ASD to promote early diagnosis and intervention.

Fever during pregnancy as a risk factor for neurodevelopmental disorders: results from a systematic review and meta-analysis

BACKGROUND

Fever during pregnancy is a relatively common and most often trivial event. However, under specific conditions, it could affect significantly fetal brain development. Few studies, with inconsistent results, investigated whether fever, regardless the pathogen, could represent a risk factor for neurodevelopmental disorders (NDD) in the offspring. We aimed to explore further this question by performing a systematic review and meta-analysis.

METHODS

Peer-reviewed studies exploring the occurrence of NDD in offspring after a fetal exposure to maternal fever were included. We specifically considered the impact of fever severity and duration, taking into consideration some confounding variables such as the use of antipyretic during pregnancy, the trimester in which the fever arose, the maternal age or smoking at time of gestation. MEDLINE, EMBASE, PsycINFO, Cochrane and Web of Science were searched without language restriction. PRISMA recommendations were followed. Odds ratio (OR) were pooled using random-effects meta-analysis. Heterogeneity in effect size across studies was studied using random-effects meta-regression analysis. (PROSPERO CRD42020182801).

RESULTS

We finally considered ten studies gathering a total of 10,304 children with NDD. Among them, 1394 were exposed to fever during pregnancy. The selected studies were divided into 5 case-control studies and 5 cohort studies. Maternal exposure to fever during pregnancy increased the risk of NDD in offspring with an OR of 1.24 [95% CI: 1.12-1.38]. Secondary analysis revealed an increased risk for NDD when fever occurred during the first trimester of gestation [OR 1.13-95% CI: 1.02-1.26].

LIMITATIONS

We excluded studies that considered infections with no evidence of fever. Another potential limitation may be the possible heterogeneity between study designs (cohorts and case-control).

CONCLUSION

Additional evidence supported the association between fever during pregnancy and increased risk for NDD in offspring. Careful monitoring should be considered for children born from mothers with a febrile episode during pregnancy (specifically during the first trimester).

Exposure to hypertonic solutions during pregnancy induces autism-like behaviors via the NFAT-5 pathway in offspring in a rat model

OBJECTIVES

to investigate the effects of hyperosmolar state (HS) on immune response and inflammation via the NFAT5 pathway and examine whether immune-mediated conditions trigger autism-like behavior in offspring.

METHODS

a pregnant rat model was performed by administering hyperosmotic solutions. Pregnant rats were divided into 2 main groups; control (group I) and hyperosmolar groups (group II). Control group rats were given % 0.25 NaCI (tap water) (n = 6), the Hyperosmolar (HO) group was further subdivided into 3 groups as; Group II a rats which were given % 3 hypertonic NaCl (n = 6), Group II b rats were given mineral water (% 3 NaHCO3+magnesium+calcium content) (n = 6), and Group II c rats were given Ayran (% 0.8 NaCl content) (n = 6). Their offspring were examined for behaviors, biochemical and histological abnormality.

RESULTS

in offspring, TNF- α, IL-17, NFAT-5, and NGF levels in the brain were significantly higher in hyperosmotic solution groups than in control rats. Exposure of pregnant rats to hyperosmotic solution resulted in autism-like behaviors in their offspring. Through immunohistochemical methods, we found that CA1 and CA2 of the hippocampus indicated decreased number of neurons in hyperosmotic solution groups compared with the control group.

CONCLUSIONS

our findings once again emphasized that the immune-mediated conditions involved in the pathophysiology of autism. NFAT5 pathway may be a key factor in the development of neuroinflammation by hyperosmotic solutions.

Prenatal maternal infection and risk for autism in offspring: A meta-analysis

While prenatal maternal infection has received attention as a preventable and treatable risk factor for autism, findings have been inconsistent. This paper presents the results of a meta-analysis to determine whether the weight of the evidence supports such an association. Studies with a categorical diagnosis of autism as the outcome and an assessment of its association with prenatal maternal infection or fever (or the data necessary to compute this association) were included. A total of 36 studies met these criteria. Two independent reviewers extracted data on study design, methods of assessment, type of infectious agent, site of infection, trimester of exposure, definition of autism, and effect size. Analyses demonstrated a statistically significant association of maternal infection/fever with autism in offspring (OR = 1.32; 95% CI = 1.20-1.46). Adjustment for evident publication bias slightly weakened this association. There was little variation in effect sizes across agent or site of infection. Small differences across trimester of exposure were not statistically significant. There was some evidence that recall bias associated with status on the outcome variable leads to differential misclassification of exposure status. Nonetheless, the overall association is only modestly reduced when studies potentially contaminated by such bias are removed. Although causality has not been firmly established, these findings suggest maternal infection during pregnancy confers an increase in risk for autism in offspring. Given the prevalence of this risk factor, it is possible that the incidence of autism would be reduced by 12%-17% if maternal infections could be prevented or safely treated in a timely manner. LAY SUMMARY: This study is a meta-analysis of the association of maternal infection during pregnancy and subsequent autism in offspring. In combining the results from 36 studies of this association we find that a significant relationship is present. The association does not vary much across the types of infections or when they occur during pregnancy. We conclude that the incidence of autism could be substantially reduced if maternal infections could be prevented or safely treated in a timely manner.

Alterations in Retrotransposition, Synaptic Connectivity, and Myelination Implicated by Transcriptomic Changes Following Maternal Immune Activation in Nonhuman Primates

BACKGROUND

Maternal immune activation (MIA) is a proposed risk factor for multiple neuropsychiatric disorders, including schizophrenia. However, the molecular mechanisms through which MIA imparts risk remain poorly understood. A recently developed nonhuman primate model of exposure to the viral mimic poly:ICLC during pregnancy shows abnormal social and repetitive behaviors and elevated striatal dopamine, a molecular hallmark of human psychosis, providing an unprecedented opportunity for studying underlying molecular correlates.

METHODS

We performed RNA sequencing across psychiatrically relevant brain regions (prefrontal cortex, anterior cingulate, hippocampus) and primary visual cortex for comparison from 3.5- to 4-year-old male MIA-exposed and control offspring-an age comparable to mid adolescence in humans.

RESULTS

We identify 266 unique genes differentially expressed in at least one brain region, with the greatest number observed in hippocampus. Co-expression networks identified region-specific alterations in synaptic signaling and oligodendrocytes. Although we observed temporal and regional differences, transcriptomic changes were shared across first- and second-trimester exposures, including for the top differentially expressed genes-PIWIL2 and MGARP. In addition to PIWIL2, several other regulators of retrotransposition and endogenous transposable elements were dysregulated following MIA, potentially connecting MIA to retrotransposition.

CONCLUSIONS

Together, these results begin to elucidate the brain-level molecular processes through which MIA may impart risk for psychiatric disease.

A systematic review of quantitative bias analysis applied to epidemiological research

BACKGROUND

Quantitative bias analysis (QBA) measures study errors in terms of direction, magnitude and uncertainty. This systematic review aimed to describe how QBA has been applied in epidemiological research in 2006-19.

METHODS

We searched PubMed for English peer-reviewed studies applying QBA to real-data applications. We also included studies citing selected sources or which were identified in a previous QBA review in pharmacoepidemiology. For each study, we extracted the rationale, methodology, bias-adjusted results and interpretation and assessed factors associated with reproducibility.

RESULTS

Of the 238 studies, the majority were embedded within papers whose main inferences were drawn from conventional approaches as secondary (sensitivity) analyses to quantity-specific biases (52%) or to assess the extent of bias required to shift the point estimate to the null (25%); 10% were standalone papers. The most common approach was probabilistic (57%). Misclassification was modelled in 57%, uncontrolled confounder(s) in 40% and selection bias in 17%. Most did not consider multiple biases or correlations between errors. When specified, bias parameters came from the literature (48%) more often than internal validation studies (29%). The majority (60%) of analyses resulted in >10% change from the conventional point estimate; however, most investigators (63%) did not alter their original interpretation. Degree of reproducibility related to inclusion of code, formulas, sensitivity analyses and supplementary materials, as well as the QBA rationale.

CONCLUSIONS

QBA applications were rare though increased over time. Future investigators should reference good practices and include details to promote transparency and to serve as a reference for other researchers.

Impact of maternal immune activation on dendritic spine development

Dendritic spines are small dendritic protrusions that harbor most excitatory synapses in the brain. The proper generation and maturation of dendritic spines are crucial for the regulation of synaptic transmission and formation of neuronal circuits. Abnormalities in dendritic spine density and morphology are common pathologies in autism and schizophrenia. According to epidemiological studies, one risk factor for these neurodevelopmental disorders is maternal infection during pregnancy. This review discusses spine alterations in animal models of maternal immune activation in the context of neurodevelopmental disorders. We describe potential mechanisms that might be responsible for prenatal infection-induced changes in the dendritic spine phenotype and behavior in offspring.

Healing autism spectrum disorder with cannabinoids: a neuroinflammatory story

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder with a multifactorial etiology. Latest researches are raising the hypothesis of a link between the onset of the main behavioral symptoms of ASD and the chronic neuroinflammatory condition of the autistic brain; increasing evidence of this connection is shedding light on new possible players in the pathogenesis of ASD. The endocannabinoid system (ECS) has a key role in neurodevelopment as well as in normal inflammatory responses and it is not surprising that many preclinical and clinical studies account for alterations of the endocannabinoid signaling in ASD. These findings lay the foundation for a better understanding of the neurochemical mechanisms underlying ASD and for new therapeutic attempts aimed at exploiting the renowned anti-inflammatory properties of cannabinoids to treat pathologies encompassed in the autistic spectrum. This review discusses the current preclinical and clinical evidence supporting a key role of the ECS in the neuroinflammatory state that characterizes ASD, providing hints to identify new biomarkers in ASD and promising therapies for the future.

Maternal immune response and air pollution exposure during pregnancy: insights from the Early Markers for Autism (EMA) study

BACKGROUND

Perinatal exposure to air pollution and immune system dysregulation are two factors consistently associated with autism spectrum disorders (ASD) and other neurodevelopmental outcomes. However, little is known about how air pollution may influence maternal immune function during pregnancy.

OBJECTIVES

To assess the relationship between mid-gestational circulating levels of maternal cytokines/chemokines and previous month air pollution exposure across neurodevelopmental groups, and to assess whether cytokines/chemokines mediate the relationship between air pollution exposures and risk of ASD and/or intellectual disability (ID) in the Early Markers for Autism (EMA) study.

METHODS

EMA is a population-based, nested case-control study which linked archived maternal serum samples collected during weeks 15-19 of gestation for routine prenatal screening, birth records, and Department of Developmental Services (DDS) records. Children receiving DDS services for ASD without intellectual disability (ASD without ID; n = 199), ASD with ID (ASD with ID; n = 180), ID without ASD (ID; n = 164), and children from the general population (GP; n = 414) with no DDS services were included in this analysis. Serum samples were quantified for 22 cytokines/chemokines using Luminex multiplex analysis technology. Air pollution exposure for the month prior to maternal serum collection was assigned based on the Environmental Protection Agency's Air Quality System data using the maternal residential address reported during the prenatal screening visit.

RESULTS

Previous month air pollution exposure and mid-gestational maternal cytokine and chemokine levels were significantly correlated, though weak in magnitude (ranging from - 0.16 to 0.13). Ten pairs of mid-pregnancy immune markers and previous month air pollutants were significantly associated within one of the child neurodevelopmental groups, adjusted for covariates (p < 0.001). Mid-pregnancy air pollution was not associated with any neurodevelopmental outcome. IL-6 remained associated with ASD with ID even after adjusting for air pollution exposure.

CONCLUSION

This study suggests that maternal immune activation is associated with risk for neurodevelopmental disorders. Furthermore, that prenatal air pollution exposure is associated with small, but perhaps biologically relevant, effects on maternal immune system function during pregnancy. Additional studies are needed to better evaluate how prenatal exposure to air pollution affects the trajectory of maternal immune activation during pregnancy, if windows of heightened susceptibility can be identified, and how these factors influence neurodevelopment of the offspring.

Interaction between Maternal Immune Activation and Antibiotic Use during Pregnancy and Child Risk of Autism Spectrum Disorder

Prenatal exposure to maternal immune activation (MIA) has been implicated as a risk factor for the development of autism spectrum disorder (ASD), though the conditions under which this elevated risk occurs are unclear. Animal literature demonstrates that antibiotic use, which affects the composition of the maternal gut microbiota, modifies the effect of MIA on neurodevelopmental outcomes in the offspring. The aim of this study was to assess whether antibiotic use during pregnancy modifies the association between MIA and subsequent risk of ASD, in a prospective birth cohort with 116 ASD cases and 860 typically developing (TD) child controls. There was no evidence of interaction between fever or genitourinary infection and antibiotic use on the odds of ASD in unadjusted or adjusted analyzes. However, we found evidence of an interaction between flu, specifically in second trimester, and antibiotic use at any point during pregnancy on the odds of ASD in the child. Among women who received an antibiotic during pregnancy, flu in trimester two was not associated with ASD (adjusted odds ratio [aOR] = 0.99 [0.43-2.28]). Among women who were not exposed to an antibiotic at any point during pregnancy, flu in second trimester was significantly associated with increased odds of ASD (aOR = 4.05 [1.14-14.38], P = .03), after adjustment for child sex, child birth year, maternal age, gestational age, C-section delivery, and low birthweight. These findings should be treated as hypothesis-generating and suggest that antibiotic use may modify the influence that MIA has on autism risk in the child. LAY SUMMARY: We looked at whether the association between activation of the immune system during pregnancy and risk of the child developing autism spectrum disorder (ASD) differed among women who did or did not take an antibiotic at any point during pregnancy. We examined 116 children with ASD and 860 without ASD and found that flu in second trimester was associated with increased ASD, but only among women who did not take an antibiotic during pregnancy. No other immune activation exposures seemed to interact with antibiotic use.

Genome, Environment, Microbiome and Metabolome in Autism (GEMMA) Study Design: Biomarkers Identification for Precision Treatment and Primary Prevention of Autism Spectrum Disorders by an Integrated Multi-Omics Systems Biology Approach

Autism Spectrum Disorder (ASD) affects approximately 1 child in 54, with a 35-fold increase since 1960. Selected studies suggest that part of the recent increase in prevalence is likely attributable to an improved awareness and recognition, and changes in clinical practice or service availability. However, this is not sufficient to explain this epidemiological phenomenon. Research points to a possible link between ASD and intestinal microbiota because many children with ASD display gastro-intestinal problems. Current large-scale datasets of ASD are limited in their ability to provide mechanistic insight into ASD because they are predominantly cross-sectional studies that do not allow evaluation of perspective associations between early life microbiota composition/function and later ASD diagnoses. Here we describe GEMMA (Genome, Environment, Microbiome and Metabolome in Autism), a prospective study supported by the European Commission, that follows at-risk infants from birth to identify potential biomarker predictors of ASD development followed by validation on large multi-omics datasets. The project includes clinical (observational and interventional trials) and pre-clinical studies in humanized murine models (fecal transfer from ASD probands) and in vitro colon models. This will support the progress of a microbiome-wide association study (of human participants) to identify prognostic microbiome signatures and metabolic pathways underlying mechanisms for ASD progression and severity and potential treatment response.

The association between maternal lipid profile after birth and offspring risk of autism spectrum disorder

PURPOSE

Maternal obesity has been consistently associated with offspring risk for ASD, as well as lipid metabolism derangements. However, few ASD studies have examined maternal lipids in conjunction with maternal prepregnancy body mass index (BMI).

METHODS

This nested case-control study was based on the Boston Birth Cohort, a prospective cohort study of mother-child dyads recruited at the Boston Medical Center. Maternal blood samples were collected shortly after delivery and analyzed for total plasma cholesterol, HDL, and triglyceride (TG) concentrations. Low-density lipoprotein (LDL) was subsequently calculated by the Friedewald equation. Cases were identified using ASD diagnoses in children's medical records. The odds of ASD were estimated with continuous lipid levels for a linear relationship, and we further explored the nonlinear relationship using the tertile of each lipid analyte with the highest tertile as the reference group. Logistic regression was used to estimate the risk of ASD adjusting for potential confounders. The analyses were performed separately for mothers with normal weight and overweight/obese based on maternal prepregnancy BMI.

RESULTS

One standard deviation decrease in postpartum maternal LDL was associated with increased odds of ASD aOR 1.35 [1.04-1.75]. There was no association between postpartum maternal HDL and TG levels and ASD risk. Decreasing levels of LDL were not associated with ASD risk in normal-weight mothers (aOR 1.2 [0.83-1.75]), but the ASD risk was more pronounced in overweight and obese mothers (aOR 1.54 [1.03-2.27]). Follow-up analysis of nonlinear association models showed that, when compared to the highest tertile, lower maternal LDL concentrations were associated with approximately two times increased risk of ASD (first tertile: aOR 2.49 [1.27-4.87] and second tertile: aOR 2.79 [1.42-5.48]). A similar pattern was observed with overweight/obese mothers but not in normal-weight mothers.

CONCLUSIONS

Lower maternal postpartum plasma LDL concentration was associated with increased odds of ASD in offspring among children born to overweight and obese mothers. Our findings suggest that both maternal BMI and lipids should be considered in assessing their role in offspring ASD risk, and additional longitudinal studies are needed to better understand maternal lipid dynamics during pregnancy among normal-weight and overweight/obese mothers.

Potential role of primed microglia during obesity on the mesocorticolimbic circuit in autism spectrum disorder

Autism spectrum disorder (ASD) is a complex neurodevelopmental disease which involves functional and structural defects in selective central nervous system (CNS) regions that harm function and individual ability to process and respond to external stimuli. Individuals with ASD spend less time engaging in social interaction compared to non-affected subjects. Studies employing structural and functional magnetic resonance imaging reported morphological and functional abnormalities in the connectivity of the mesocorticolimbic reward pathway between the nucleus accumbens and the ventral tegmental area (VTA) in response to social stimuli, as well as diminished medial prefrontal cortex in response to visual cues, whereas stronger reward system responses for the non-social realm (e.g., video games) than social rewards (e.g., approval), associated with caudate nucleus responsiveness in ASD children. Defects in the mesocorticolimbic reward pathway have been modulated in transgenic murine models using D2 dopamine receptor heterozygous (D2+/-) or dopamine transporter knockout mice, which exhibit sociability deficits and repetitive behaviors observed in ASD phenotypes. Notably, the mesocorticolimbic reward pathway is modulated by systemic and central inflammation, such as primed microglia, which occurs during obesity or maternal overnutrition. Therefore, we propose that a positive energy balance during obesity/maternal overnutrition coordinates a systemic and central inflammatory crosstalk that modulates the dopaminergic neurotransmission in selective brain areas of the mesocorticolimbic reward pathway. Here, we will describe how obesity/maternal overnutrition may prime microglia, causing abnormalities in dopamine neurotransmission of the mesocorticolimbic reward pathway, postulating a possible immune role in the development of ASD.

Microglial and peripheral immune priming is partially sexually dimorphic in adolescent mouse offspring exposed to maternal high-fat diet

Background

Maternal nutrition is critical for proper fetal development. While increased nutrient intake is essential during pregnancy, an excessive consumption of certain nutrients, like fat, can lead to long-lasting detrimental consequences on the offspring. Animal work investigating the consequences of maternal high-fat diet (mHFD) revealed in the offspring a maternal immune activation (MIA) phenotype associated with increased inflammatory signals. This inflammation was proposed as one of the mechanisms causing neuronal circuit dysfunction, notably in the hippocampus, by altering the brain-resident macrophages—microglia. However, the understanding of mechanisms linking inflammation and microglial activities to pathological brain development remains limited. We hypothesized that mHFD-induced inflammation could prime microglia by altering their specific gene expression signature, population density, and/or functions.

Methods

We used an integrative approach combining molecular (i.e., multiplex-ELISA, rt-qPCR) and cellular (i.e., histochemistry, electron microscopy) techniques to investigate the effects of mHFD (saturated and unsaturated fats) vs control diet on inflammatory priming, as well as microglial transcriptomic signature, density, distribution, morphology, and ultrastructure in mice. These analyses were performed on the mothers and/or their adolescent offspring at postnatal day 30.

Results

Our study revealed that mHFD results in MIA defined by increased circulating levels of interleukin (IL)-6 in the mothers. This phenotype was associated with an exacerbated inflammatory response to peripheral lipopolysaccharide in mHFD-exposed offspring of both sexes. Microglial morphology was also altered, and there were increased microglial interactions with astrocytes in the hippocampus CA1 of mHFD-exposed male offspring, as well as decreased microglia-associated extracellular space pockets in the same region of mHFD-exposed offspring of the two sexes. A decreased mRNA expression of the inflammatory-regulating cytokine Tgfb1 and microglial receptors Tmem119, Trem2, and Cx3cr1 was additionally measured in the hippocampus of mHFD-exposed offspring, especially in males.

Conclusions

Here, we described how dietary habits during pregnancy and nurturing, particularly the consumption of an enriched fat diet, can influence peripheral immune priming in the offspring. We also found that microglia are affected in terms of gene expression signature, morphology, and interactions with the hippocampal parenchyma, in a partially sexually dimorphic manner, which may contribute to the adverse neurodevelopmental outcomes on the offspring.

A prospective birth cohort study on cord blood folate subtypes and risk of autism spectrum disorder

BACKGROUND

We previously reported that extremely high concentrations of maternal plasma folate were associated with increased risk of autism spectrum disorder (ASD) in children. This study explored whether specific types of folate in cord blood have differential association with ASD.

OBJECTIVES

In the Boston Birth Cohort (BBC), we assessed the association between cord blood unmetabolized folic acid (UMFA), 5-methyl tetrahydrofolate (THF), and total folate and a child's ASD risk. In a subset, we explored whether the association between UMFA and ASD risk can be affected by the dihydrofolate reductase (DHFR) genotype and cord plasma creatinine. We also examined prenatal correlates of cord UMFA concentrations.

METHODS

This report included 567 BBC children (92 ASD, 475 neurotypical), who were recruited at birth and prospectively followed at the Boston Medical Center. ASD was defined from International Classification of Diseases (ICD)-9 and ICD-10 codes documented in electronic medical records.

RESULTS

Children with cord UMFA in the highest, versus lowest quartile, had a greater ASD risk (adjusted OR, aORquartile4: 2.26; 95% CI: 1.08, 4.75). When stratified by race/ethnicity, the association was limited to 311 (45 ASD) Black children (aORquartile4: 9.85; 95% CI: 2.53, 38.31); a test of interaction between race/ethnicity and cord UMFA concentrations was significant (P = 0.007). The UMFA-ASD association in Black children slightly attenuated after adjusting for cord plasma creatinine (P = 0.05). There was no significant association between cord 5-methyl THF, total folate, DHFR genotype, and ASD risk. Cord total folate and maternal supplement intake during second trimester were associated with higher cord UMFA.

CONCLUSIONS

Higher concentrations of cord UMFA, but not 5-methyl THF or total folate, were associated with a greater risk of ASD in Black children. This study in a preterm-birth-enriched cohort raises more questions than it could answer and underscores the need for additional investigations on the sources and role of cord UMFA in children's neurodevelopmental outcomes and underlying mechanisms.

Maternal Systemic Lupus Erythematosus, Rheumatoid Arthritis, and Risk for Autism Spectrum Disorders in Offspring: A Meta-analysis

This study assessed the relationships between maternal systemic lupus erythematosus (SLE) or rheumatoid arthritis (RA) and risk for autism spectrum disorders (ASDs) in offspring. Seven observational studies, including 25,005 ASD cases and 4,543,321 participants, were included for meta-analysis. Pooled results by using random-effects models suggested that maternal RA was associated with an increased risk for ASDs [odds ratio (OR) 1.39, 95% confidence interval (CI) 1.16-1.67], while maternal SLE was associated with an increased risk for ASDs only in western population (OR 1.91, 95% CI 1.02-3.57). Further study is warranted to confirm these results.

Acetaminophen use during pregnancy and the risk of attention deficit hyperactivity disorder: A causal association or bias?

BACKGROUND

The association between acetaminophen use during pregnancy and the development of attention deficit hyperactivity disorder (ADHD) in the offspring may be due to bias.

OBJECTIVES

The primary objective was to assess the role of potential unmeasured confounding in the estimation of the association between acetaminophen use during pregnancy and the risk of ADHD, through bias analysis. The secondary objective was to assess the roles of selection bias and exposure misclassification.

DATA SOURCES

We searched MEDLINE, Embase, Scopus, and the Cochrane Library up to December 2018.

STUDY SELECTION AND DATA EXTRACTION

We included observational studies examining the association between acetaminophen use during pregnancy and the risk of ADHD.

SYNTHESIS

We meta-analysed data across studies, using random-effects model. We conducted a bias analysis to studies that did not adjust for important confounders, to explore systematic errors related to unmeasured confounding, selection bias, and exposure misclassification.

RESULTS

The search resulted in seven studies included in our meta-analysis. When adjusted estimates were pooled across all studies, the risk ratio (RR) for ADHD was 1.35 (95% confidence interval [CI] 1.25, 1.46; I²  = 48%). Sensitivity analysis for unmeasured confounding in this meta-analysis showed that a confounder of 1.69 on the RR scale would reduce to 10% the proportion of studies with a true effect size of RR >1.10. Unmeasured confounding bias analysis decreased the point estimate in five of the seven studies and increased in two studies, suggesting that the observed association could be confounded by parental ADHD. Unadjusted and bias-corrected risk ratios (bcRRs) were: RR = 1.34, bcRR = 1.13; RR = 1.51, bcRR = 1.17; RR = 1.63, bcRR = 1.38; RR = 1.44, bcRR = 1.17; RR = 1.16, bcRR = 1.18; RR = 1.25, bcRR = 1.05; and RR = 0.99, bcRR = 1.18.

CONCLUSIONS

Bias analysis suggests that the previously reported association between acetaminophen use during pregnancy and an increased risk of ADHD in the offspring may be due to unmeasured confounding. Our ability to conclude a causal association is limited.

Maternal and Child Health Bureau's Autism Research Program

OBJECTIVES

To provide an overview and quantitatively demonstrate the reach of the Health Resources and Services Administration's Maternal and Child Health Bureau autism research program.

METHODS

We reviewed program reports and internal data from 59 autism research grantees. The US federal Interagency Autism Coordinating Committee's strategic plan questions were used as a framework to highlight the contributions of the autism research program in advancing the field.

RESULTS

The autism research program grantees advance research in several ways. Grantees have strengthened the evidence for autism interventions by conducting 89 studies at 79 distinct research sites. A total of 212 708 participants have enrolled in autism research program studies and 361 researchers have contributed to furthering autism research. The program addresses topics that align with the majority of the Interagency Autism Coordinating Committee's priority topic areas, including advancements in treatments and interventions, services and supports, and identifying risk factors. Grantee products include 387 peer-reviewed publications, 19 tools, and 13 practice guidelines for improving care and intervention practices.

CONCLUSIONS

The autism research program has contributed to medical advances in research, leveraged innovative training platforms to provide specialized training, and provided access to health services through research-based screening and diagnostic procedures. Autism research program studies have contributed to the development of evidence-based practice guidelines, informed policy guidelines, and quality improvement efforts to bolster advancements in the field. Although disparities still exist, the Health Resources and Services Administration's Maternal and Child Health Bureau can reduce gaps in screening and diagnosis by targeting interventions to underserved populations including minority and rural communities.

Cell Therapy Targets for Autism Spectrum Disorders: Hopes, Challenges and Future Directions

Autism spectrum disorders as a group of pediatric neurodevelopmental diseases is a crucial part of the worldwide disabilities which have influence in communication skills, social interactions, and ability to understand the concepts. The precise pathophysiology of autism spectrum disorders due to the abundance of involved mechanisms is unknown. Some of these involved mechanisms are related to genetic factors, chronic neuro inflammation, mitochondrial dysfunction, oxidative stress, immune dysregulation, hormonal imbalance, and environmental factors. Current main treatments for autisms are behavioral, nutritional and medical therapies, however there is not definitive treatment approach. Therein, more novel therapies are still required to improve the symptoms. Several preclinical and clinical evidence were shown that stem cell therapy is a potential treatment option for autism spectrum disorders individuals. Considering the significant factors which can affect the outcome of stem cell therapeutic effects including stem cell types, route and dosage of administration, and mechanism of activity along with selecting best animal models can be very important in performing clinical trials.

Infection and Fever in Pregnancy and Autism Spectrum Disorders: Findings from the Study to Explore Early Development

Maternal infection and fever during pregnancy have been implicated in the etiology of autism spectrum disorder (ASD); however, studies have not been able to separate the effects of fever itself from the impact of a specific infectious organism on the developing brain. We utilized data from the Study to Explore Early Development (SEED), a case-control study among 2- to 5-year-old children born between 2003 and 2006 in the United States, to explore a possible association between maternal infection and fever during pregnancy and risk of ASD and other developmental disorders (DDs). Three groups of children were included: children with ASD (N = 606) and children with DDs (N = 856), ascertained from clinical and educational sources, and children from the general population (N = 796), randomly sampled from state birth records. Information about infection and fever during pregnancy was obtained from a telephone interview with the mother shortly after study enrollment and maternal prenatal and labor/delivery medical records. ASD and DD status was determined by an in-person standardized developmental assessment of the child at 3-5 years of age. After adjustment for covariates, maternal infection anytime during pregnancy was not associated with ASD or DDs. However, second trimester infection accompanied by fever elevated risk for ASD approximately twofold (aOR = 2.19, 95% confidence interval 1.14-4.23). These findings of an association between maternal infection with fever in the second trimester and increased risk of ASD in the offspring suggest that the inflammatory response to the infectious agent may be etiologically relevant. Autism Res 2019, 12: 1551-1561. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Using data from a large multisite study in the United States-the Study to Explore Early Development-we found that women who had an infection during the second trimester of pregnancy accompanied by a fever are more likely to have children with ASD. These findings suggest the possibility that only more severe infections accompanied by a robust inflammatory response increase the risk of ASD.

Neuroimmunology of the female brain across the lifespan: Plasticity to psychopathology

The female brain is highly dynamic and can fundamentally remodel throughout the normal ovarian cycle as well as in critical life stages including perinatal development, pregnancy and old-age. As such, females are particularly vulnerable to infections, psychological disorders, certain cancers, and cognitive impairments. We will present the latest evidence on the female brain; how it develops through the neonatal period; how it changes through the ovarian cycle in normal individuals; how it adapts to pregnancy and postpartum; how it responds to illness and disease, particularly cancer; and, finally, how it is shaped by old age. Throughout, we will highlight female vulnerability to and resilience against disease and dysfunction in the face of environmental challenges.

Preterm birth subtypes, placental pathology findings, and risk of neurodevelopmental disabilities during childhood

INTRODUCTION

Preterm birth (PTB) and in-utero inflammation are recognized risk factors of neurodevelopmental disabilities (NDDs); however, their combined role in NDDs is unknown. We examined the independent and joint association of PTB and placental histological findings with the childhood risk of NDDs (overall and by subgroups including autism spectrum disorder (ASD) and ADHD).

METHODS

We analyzed data from the Boston Birth Cohort, where mother-infant pairs were enrolled at birth and followed from birth onwards. Birth outcomes, placental pathology and NDDs were obtained from electronic medical records. Placental pathology was categorized using a standardized classification system proposed by the Amsterdam Placental Workshop Group.

RESULTS

PTB (all, including spontaneous, medically indicated) was an independent risk factor for NDDs. Placental histological chorioamnionitis (CA) and PTB additively increased the odds of NDDs (aOR: 2.16, 95% CI: 1.37, 3.39), as well as ADHD (aOR: 2.75, 95% CI: 1.55, 4.90), other developmental disabilities (aOR: 1.96, 95% CI: 1.18, 3.25) and possibly ASD (aOR: 2.31, 95% CI: 0.99, 5.39). The above associations were more pronounced in spontaneous than medically indicated PTB. PTB alone in the absence of CA only had a moderate association with ASD and ADHD. Placental maternal vascular malperfusion alone or in combination with PTB was not associated with the risk of NDDs.

DISCUSSION

Our study provided new insights on PTB and NDDs by further considering preterm subtypes and placental histology. We revealed that children of spontaneous PTB along with histological CA were at the highest risk for a spectrum of NDDs.

Neonatal Inhibition of Connexin 36 Ameliorates Fetal Brain Injury Induced by Maternal Noninfectious Fever in Mice

Prenatal fever could result in brain function impairments in the offspring. The present study investigated the effect of interleukin-6 (IL-6)-induced maternal fever on the offspring and the involvement of connexin 36 in this process. Pregnant C57BL/6J mice were injected with IL-6 on gestational day 15. The levels of iNOS and COX-2 were measured as an index of neuroinflammation in the brain of newborn pups. Offspring were treated with the connexin 36 (Cx36) inhibitor mefloquine at postnatal day (P)1-P3 or at P40-P42. Rotarod, grip traction, and foot fault tests were carried out to evaluate the motor behavior of adult offspring. Injection of IL-6 led to an elevation of the core temperature in the pregnant dams. Offspring of these dams showed significantly increased COX-2 and iNOS mRNA expression and protein levels in the whole-brain samples and significantly increased Cx36 in the cerebellum. Moreover, offspring of these dams showed motor deficits at an adult age. Neonatal administration of the Cx36 inhibitor mefloquine could prevent these motor deficits. Maternal fever during pregnancy induced by IL-6 injection could lead to neuroinflammation and motor deficits in the offspring. Neonatal inhibition of Cx36 could ameliorate the motor deficits in the offspring, indicating an involvement of Cx36 in the IL-6-induced maternal fever.

Cord and Early Childhood Plasma Adiponectin Levels and Autism Risk: A Prospective Birth Cohort Study

Emerging research suggests that adiponectin, a cytokine produced by adipose tissue, may be implicated in ASD. In this prospective birth cohort study (n = 847), we assessed the association between cord, early childhood plasma adiponectin and the risk of developing ASD. ASD was defined based on ICD codes of physician diagnosis. Cord adiponectin levels were inversely associated with ASD risk (aOR 0.50; 95% CI 0.33, 0.77), independent of preterm birth, early childhood adiponectin and other known ASD risk factors. Early childhood adiponectin, assessed prior to ASD diagnosis, was associated with lower risk of ASD, which attenuated after adjusting for cord adiponectin, indicating the relative importance of cord adiponectin in ASD risk. Further research is warranted to confirm our findings and elucidate biological mechanisms.

Risk and Protective Environmental Factors Associated with Autism Spectrum Disorder: Evidence-Based Principles and Recommendations

Autism Spectrum Disorder (ASD) is a complex condition with early childhood onset, characterized by a set of common behavioral features. The etiology of ASD is not yet fully understood; however, it reflects the interaction between genetics and environment. While genetics is now a well-established risk factor, several data support a contribution of the environment as well. This paper summarizes the conclusions of a consensus conference focused on the potential pathogenetic role of environmental factors and on their interactions with genetics. Several environmental factors have been discussed in terms of ASD risk, namely advanced parental age, assisted reproductive technologies, nutritional factors, maternal infections and diseases, environmental chemicals and toxicants, and medications, as well as some other conditions. The analysis focused on their specific impact on three biologically relevant time windows for brain development: the periconception, prenatal, and early postnatal periods. Possible protective factors that might prevent or modify an ASD trajectory have been explored as well. Recommendations for clinicians to reduce ASD risk or its severity have been proposed. Developments in molecular biology and big data approaches, which are able to assess a large number of coexisting factors, are offering new opportunities to disentangle the gene⁻environment interplay that can lead to the development of ASD.

Infections in children with autism spectrum disorder: Study to Explore Early Development (SEED)

Immune system abnormalities have been widely reported among children with autism spectrum disorder (ASD), which may increase the risk of childhood infections. The Study to Explore Early Development (SEED) is a multisite case-control study of children aged 30-69 months, born in 2003-2006. Cases are children previously diagnosed and newly identified with ASD enrolled from education and clinical settings. Children with a previously diagnosed non-ASD developmental condition were included in the developmental delay/disorder (DD) control group. The population (POP) control group included children randomly sampled from birth certificates. Clinical illness from infection during the first 28 days ("neonatal," from medical records) and first three years of life (caregiver report) in cases was compared to DD and POP controls; and between cases with and without regression. Children with ASD had greater odds of neonatal (OR = 1.8; 95%CI: 1.1, 2.9) and early childhood infection (OR = 1.7; 95%CI: 1.5, 1.9) compared to POP children, and greater odds of neonatal infection (OR = 1.5; 95%CI: 1.1, 2.0) compared to DD children. Cases with regression had 1.6 times the odds (95%CI: 1.1, 2.3) of caregiver-reported infection during the first year of life compared to cases without regression, but neonatal infection risk and overall early childhood infection risk did not differ. Our results support the hypothesis that children with ASD are more likely to have infection early in life compared to the general population and to children with other developmental conditions. Future studies should examine the contributions of different causes, timing, frequency, and severity of infection to ASD risk. Autism Research 2019, 12: 136-146. © 2018 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: We looked at infections during early childhood in relation to autism spectrum disorder (ASD). We found that children with ASD were more likely to have an infection in the first 28 days of life and before age three compared to children with typical development. Children with ASD were also more likely than children with other developmental delays or disorders to have an infection in the first 28 days of life.

Prenatal paracetamol exposure and child neurodevelopment: A review

BACKGROUND

The non-prescription medication paracetamol (acetaminophen, APAP) is currently recommended as a safe pain and fever treatment during pregnancy. However, recent studies suggest a possible association between APAP use in pregnancy and offspring neurodevelopment.

OBJECTIVES

To conduct a review of publications reporting associations between prenatal APAP use and offspring neurodevelopmental outcomes.

METHODS

Relevant sources were identified through a key word search of multiple databases (Medline, CINAHL, OVID and TOXNET) in September 2016. All English language observational studies of pregnancy APAP and three classes of neurodevelopmental outcomes (autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), and intelligence quotient (IQ)) were included. One reviewer (AZB) independently screened all titles and abstracts, extracted and analyzed the data.

RESULTS

64 studies were retrieved and 55 were ineligible. Nine prospective cohort studies fulfilled all inclusion criteria. Data pooling was not appropriate due to heterogeneity in outcomes. All included studies suggested an association between prenatal APAP exposure and the neurodevelopmental outcomes; ADHD, ASD, or lower IQ. Longer duration of APAP use was associated with increased risk. Associations were strongest for hyperactivity and attention-related outcomes. Little modification of associations by indication for use was reported.

CONCLUSIONS

Together, these nine studies suggest an increased risk of adverse neurodevelopmental outcomes following prenatal APAP exposure. Further studies are urgently needed with; precise indication of use and exposure assessment of use both in utero and in early life. Given the current findings, pregnant women should be cautioned against indiscriminate use of APAP. These results have substantial public health implications.

A Prospective Birth Cohort Study on Maternal Cholesterol Levels and Offspring Attention Deficit Hyperactivity Disorder: New Insight on Sex Differences

Growing evidence suggests that maternal cholesterol levels are important in the offspring’s brain growth and development. Previous studies on cholesterols and brain functions were mostly in adults. We sought to examine the prospective association between maternal cholesterol levels and the risk of attention deficit hyperactivity disorder (ADHD) in the offspring. We analyzed data from the Boston Birth Cohort, enrolled at birth and followed from birth up to age 15 years. The final analyses included 1479 mother-infant pairs: 303 children with ADHD, and 1176 neurotypical children without clinician-diagnosed neurodevelopmental disorders. The median age of the first diagnosis of ADHD was seven years. The multiple logistic regression results showed that a low maternal high-density lipoprotein level (≤60 mg/dL) was associated with an increased risk of ADHD, compared to a higher maternal high-density lipoprotein level, after adjusting for pertinent covariables. A “J” shaped relationship was observed between triglycerides and ADHD risk. The associations with ADHD for maternal high-density lipoprotein and triglycerides were more pronounced among boys. The findings based on this predominantly urban low-income minority birth cohort raise a new mechanistic perspective for understanding the origins of ADHD and the gender differences and future targets in the prevention of ADHD.

Fever in pregnancy and offspring head circumference

PURPOSE

To examine whether maternal fever during pregnancy is associated with reduced head circumference and risk of microcephaly at birth.

METHODS

A prospective study of 86,980 live-born singletons within the Danish National Birth Cohort was carried out. Self-reported maternal fever exposure was ascertained in two interviews during pregnancy and information on head circumference at birth was extracted from the Danish Medical Birth Registry.

RESULTS

Fever in pregnancy was reported by 27% of the mothers, and we identified 3370 cases of microcephaly (head circumference less than or equal to third percentile for sex and gestational age) and 1140 cases of severe microcephaly (head circumference less than or equal to first percentile for sex and gestational age). In this study, maternal fever exposure was not associated with reduced head circumference (adjusted β = 0.03, 95% confidence intervals [CI]: 0.01-0.05), increased risk of microcephaly (odds ratio: 0.95, 95% CI: 0.88-1.03) nor severe microcephaly (odds ratio: 1.01, 95% CI: 0.88-1.15) in the offspring. These findings were consistent for increasing numbers of fever episodes, for increasing fever severity, and for exposure in both early pregnancy and midpregnancy.

CONCLUSIONS

In this most comprehensive study to date, we found no indication that maternal fever in pregnancy is associated with small head size in the offspring.