Maternal immune activation and autism spectrum disorder: interleukin-6 signaling as a key mechanistic pathway

Neurodevelopmental delay in children exposed to maternal SARS-CoV-2 in-utero

It is unclear if SARS CoV-2 infection during pregnancy is associated with adverse neurodevelopmental repercussions to infants. We assessed pediatric neurodevelopmental outcomes in children born to mothers with laboratory-confirmed SARS CoV-2 infection during pregnancy. Neurodevelopmental outcomes of in-utero exposed children were compared to that of pre-pandemic control children in Los Angeles (LA), CA, USA and Rio de Janeiro, Brazil. Bayley Scales of Infant and Toddler Development, 3rd edition (Bayley-III), the gold standard tool for evaluating neurodevelopment until 36 months of age and Ages and Stages Questionnaires (ASQ-3), a frequently used screening instrument for evaluating neurodevelopment in this same age group were the assessment tools used. Developmental delay (DD) was defined as having a score < - 2 SD below the norm (< 70) in at least one of three Bayley-III domains, (cognitive, motor or language) or a score below the cut-off (dark zone) in at least one of five ASQ-3 domains (communication, gross motor, fine motor, problem solving, personal-social). Exposed children were born between April 2020 and December 2022 while control children were born between January 2016 to December 2019. Neurodevelopmental testing was performed in 300 children total: 172 COVID-19 exposed children between 5-30 months of age and 128 control children between 6-38 months of age. Bayley-III results demonstrated that 12 of 128 exposed children (9.4%) had DD versus 2 of 128 controls (1.6%), p = 0.0007. Eight of 44 additional exposed children had DD on ASQ-3 testing. Fully, 20 of 172 exposed children (11.6%) and 2 of 128 control children (1.6%), p = 0.0006 had DD. In Rio, 12% of exposed children versus 2.6% of controls, p = 0.02 had DD. In LA, 5.7% of exposed children versus 0 controls, p = 0.12 had DD. Severe/critical maternal COVID-19 predicted below average neurodevelopment in the exposed cohort (OR 2.6, 95% CI 1.1-6.4). Children exposed to antenatal COVID-19 have a tenfold higher frequency of DD as compared to controls and should be offered neurodevelopmental follow-up.

LPS-induced inflammation in rats during pregnancy reduces maternal melatonin and impairs neurochemistry and behavior of adult male offspring

Inflammation during pregnancy can induce neurodevelopmental changes that affect the neurological health of offspring. Elevated levels of circulating inflammatory cytokines have been shown to decrease nocturnal melatonin synthesis by the pineal gland, potentially impacting fetal development. This study aimed to assess the effects of LPS-induced inflammation on melatonin concentrations in the plasma of pregnant female rats and explore resulting neurochemical and behavioral changes in their offspring. Our findings revealed that pregnant rats injected with LPS experienced decreased nocturnal melatonin levels in their plasma, with an increase in diurnal melatonin content. The offspring exhibited reduced performance in tests evaluating motor coordination and spatial memory compared to control subjects. Immunohistochemical analysis indicated a decline in calbindin immunoreactivity in Purkinje cells in the cerebellum. Additionally, the hippocampus displayed an increase in IBA-1 and calretinin expression, coupled with a reduction in parvalbumin expression in the offspring of the LPS group. Collectively, this study provides compelling evidence that an inflammatory state can lead to a reduction in melatonin synthesis in pregnant females, potentially impacting the neurodevelopment of offspring, including neuronal, glial, motor, and cognitive aspects. Subsequent studies will further elucidate the mechanisms underlying inflammation-induced maternal melatonin reduction and its impact on offspring neurodevelopment.

Pre-autism: What a paediatrician should know about early diagnosis of autism‎

Autism, also known as an autism spectrum disorder, is a complex neurodevelopmental disorder usually diagnosed in the first three years of a child's life. A range of symptoms characterizes it and can be diagnosed at any age, including adolescence and adulthood. However, early diagnosis is crucial for effective management, prognosis, and care. Unfortunately, there are no established fetal, prenatal, or newborn screening programs for autism, making early detection difficult. This review aims to shed light on the early detection of autism prenatally, natally, and early in life, during a stage we call as "pre-autism" when typical symptoms are not yet apparent. Some fetal, neonatal, and infant biomarkers may predict an increased risk of autism in the coming baby. By developing a biomarker array, we can create an objective diagnostic tool to diagnose and rank the severity of autism for each patient. These biomarkers could be genetic, immunological, hormonal, metabolic, amino acids, acute phase reactants, neonatal brainstem function biophysical activity, behavioral profile, body measurements, or radiological markers. However, every biomarker has its accuracy and limitations. Several factors can make early detection of autism a real challenge. To improve early detection, we need to overcome various challenges, such as raising community awareness of early signs of autism, improving access to diagnostic tools, reducing the stigma attached to the diagnosis of autism, and addressing various culturally sensitive concepts related to the disorder.

Maternal rheumatoid arthritis and risk of autism in the offspring

BACKGROUND

Maternal Rheumatoid Arthritis (RA) is suggested to increase the risk of Autism Spectrum Disorder (ASD) in the offspring, mainly through inflammation/autoimmunity, but the association is unclear. A prospective population-based cohort study was implemented to examine the association between maternal RA and offspring ASD.

METHODS

We included all children born alive in Sweden from 1995 to 2015, followed up through 2017. Diagnoses of ASD and RA were clinically ascertained from National Patient Register. We quantified the association by hazard ratios (HR) and two-sided 95% confidence intervals (CI), from Cox regression after detailed adjustment for potential confounders. We examined RA serostatus, etiological subgroups and the timing of exposure. To closer examine the underlying mechanism for the association, we included a negative control group for RA, arthralgia, with similar symptomology as RA but free from inflammation/autoimmunity.

RESULTS

Of 3629 children born to mothers with RA, 70 (1.94%) were diagnosed with ASD, compared to 28 892 (1.92%) of 1 503 908 children born to mothers without RA. Maternal RA before delivery was associated with an increased risk of offspring ASD (HR = 1.43, 95% CI 1.11-1.84), especially for seronegative RA (HR = 1.61, 95% CI 1.12-2.30). No similar association was observed for paternal RA, maternal sisters with RA, or RA diagnosed after delivery. Maternal arthralgia displayed as high risks for offspring ASD as did maternal RA (HR = 1.41, 95% CI 1.24-1.60).

CONCLUSIONS

In Sweden, maternal RA before delivery was associated with an increased risk of offspring ASD. The comparable association between maternal arthralgia and ASD risk suggests other pathways of risk than autoimmunity/inflammation, acting jointly or independently of RA.

Link between the skin and autism spectrum disorder

Autism spectrum disorder (ASD) is a common neurological disorder. Although the etiologies of ASD have been widely speculated, evidence also supports the pathogenic role of cutaneous inflammation in autism. The prevalence of ASD is higher in individuals with inflammatory dermatoses than in those without inflammatory diseases. Anti-inflammation therapy alleviates symptoms of ASD. Recent studies suggest a link between epidermal dysfunction and ASD. In the murine model, mice with ASD display epidermal dysfunction, accompanied by increased expression levels of proinflammatory cytokines in both the skin and the brain. Children with ASD, which develops in their early lifetime, also exhibit altered epidermal function. Interestingly, improvement in epidermal function alleviates some symptoms of ASD. This line of evidence suggests a pathogenic role of cutaneous dysfunction in ASD. Either an improvement in epidermal function or effective treatment of inflammatory dermatoses can be an alternative approach to the management of ASD. We summarize here the current evidence of the association between the skin and ASD.

Maternal atopic conditions and autism spectrum disorder: a systematic review

Autism spectrum disorder (ASD) is a disabling neurodevelopmental condition with complex etiology. Emerging evidence has pointed to maternal atopy as a possible risk factor. It is hypothesized that maternal atopic disease during pregnancy can lead to increased levels of inflammatory cytokines in fetal circulation via placental transfer or increased production. These cytokines can then pass through the immature blood-brain barrier, causing aberrant neurodevelopment via mechanisms including premature microglial activation. The objective of this study is to systematically review observational studies that investigate whether a maternal history of atopic disease (asthma, allergy, or eczema/atopic dermatitis) is associated with a diagnosis of ASD in offspring. A search was conducted in Ovid MEDLINE, PsycINFO, and Embase databases for relevant articles up to November 2021; this was later updated in January 2022. Observational studies published in peer-reviewed journals were included. Data were synthesized and qualitatively analyzed according to the specific atopic condition. Quality assessment was done using the Newcastle-Ottawa Scale. Nine articles were identified, with all including asthma as an exposure, alongside four each for allergy and eczema. Findings were inconsistent regarding the association between a maternal diagnosis of either asthma, allergy, or eczema, and ASD in offspring, with variations in methodology contributing to the inconclusiveness. More consistent associations were demonstrated regarding maternal asthma that was treated or diagnosed during pregnancy. Evidence suggests that symptomatic maternal asthma during pregnancy could be associated with ASD in offspring, underscoring the importance of effective management of atopic conditions during pregnancy. Further research is needed, particularly longitudinal studies that use gold-standard assessment tools and correlate clinical outcomes with laboratory and treatment data.PROSPERO Registration Number and Date: CRD42018116656, 26.11.2018.

Exploring potential impacts of pregnancy-related maternal immune activation and extracellular vesicles on immune alterations observed in autism spectrum disorder

Autism Spectrum Disorder (ASD) is a set of neurodevelopmental disorders usually observed in early life, with impacts on behavioral and social skills. Incidence of ASD has been dramatically increasing worldwide, possibly due to increase in awareness/diagnosis as well as to genetic and environmental triggers. Currently, it is estimated that ∼1% of the world population presents ASD symptoms. In addition to its genetic background, environmental and immune-related factors also influence the ASD etiology. In this context, maternal immune activation (MIA) has recently been suggested as a component potentially involved in ASD development. In addition, extracellular vesicles (EVs) are abundant at the maternal-fetal interface and are actively involved in the immunoregulation required for a healthy pregnancy. Considering that alterations in concentration and content of EVs have also been associated with ASD, this article raises a debate about the potential roles of EVs in the processes surrounding MIA. This represents the major differential of the present review compared to other ASD studies. To support the suggested correlations and hypotheses, findings regarding the roles of EVs during pregnancy and potential influences on ASD are discussed, along with a review and update concerning the participation of infections, cytokine unbalances, overweight and obesity, maternal anti-fetal brain antibodies, maternal fever, gestational diabetes, preeclampsia, labor type and microbiota unbalances in MIA and ASD.

Developmental Stage-Dependent Changes in Mitochondrial Function in the Brain of Offspring Following Prenatal Maternal Immune Activation

Maternal immune activation (MIA) is an important risk factor for neurodevelopmental disorders such as autism. The aim of the current study was to investigate the development-dependent changes in the mitochondrial function of MIA-exposed offspring, which may contribute to autism-like deficits. MIA was evoked by the single intraperitoneal administration of lipopolysaccharide to pregnant rats at gestation day 9.5, and several aspects of mitochondrial function in fetuses and in the brains of seven-day-old pups and adolescent offspring were analyzed along with oxidative stress parameters measurement. It was found that MIA significantly increased the activity of NADPH oxidase (NOX), an enzyme generating reactive oxygen species (ROS) in the fetuses and in the brain of seven-day-old pups, but not in the adolescent offspring. Although a lower mitochondrial membrane potential accompanied by a decreased ATP level was already observed in the fetuses and in the brain of seven-day-old pups, persistent alterations of ROS, mitochondrial membrane depolarization, and lower ATP generation with concomitant electron transport chain complexes downregulation were observed only in the adolescent offspring. We suggest that ROS observed in infancy are most likely of a NOX activity origin, whereas in adolescence, ROS are produced by damaged mitochondria. The accumulation of dysfunctional mitochondria leads to the intense release of free radicals that trigger oxidative stress and neuroinflammation, resulting in an interlinked vicious cascade.

Poly(I:C)-induced maternal immune activation causes elevated self-grooming in male rat offspring: Involvement of abnormal postpartum static nursing in dam

Introduction: Maternal immune activation (MIA) is closely related to the onset of autism-like behaviors in offspring, but the mechanism remains unclear. Maternal behaviors can influence offspring’s development and behaviors, as indicated in both human and animal studies. We hypothesized that abnormal maternal behaviors in MIA dams might be other factors leading to delayed development and abnormal behaviors in offspring.

Methods: To verify our hypothesis, we analyzed poly(I:C)-induced MIA dam’s postpartum maternal behavior and serum levels of several hormones related to maternal behavior. Pup’s developmental milestones and early social communication were recorded and evaluated in infancy. Other behavioral tests, including three-chamber test, self-grooming test, open field test, novel object recognition test, rotarod test and maximum grip test, were performed in adolescence of pups.

Results: Our results showed that MIA dams exhibit abnormal static nursing behavior but normal basic care and dynamic nursing behavior. The serum levels of testosterone and arginine vasopressin in MIA dams were significantly reduced compared with control dams. The developmental milestones, including pinna detachment, incisor eruption and eye opening, were significantly delayed in MIA offspring compared with control offspring, while the weight and early social communication showed no significant differences between the two groups. Behavioral tests performed in adolescence showed that only male MIA offspring display elevated self-grooming behaviors and reduced maximum grip.

Discussion: In conclusion, MIA dams display abnormal postpartum static nursing behavior concomitantly with reduced serum levels of testosterone and arginine vasopressin, possibly involving in the pathogenesis of delayed development and elevated self-grooming in male offspring. These findings hint that improving dam’s postpartum maternal behavior might be a potential regime to counteract delayed development and elevated self-grooming in male MIA offspring.

IL-6 and IL-8: An Overview of Their Roles in Healthy and Pathological Pregnancies

Interleukin-6 (IL-6) is an acknowledged inflammatory cytokine with a pleiotropic action, mediating innate and adaptive immunity and multiple physiological processes, including protective and regenerative ones. IL-8 is a pro-inflammatory CXC chemokine with a primary function in attracting and activating neutrophils, but also implicated in a variety of other cellular processes. These two ILs are abundantly expressed at the feto-maternal interface over the course of a pregnancy and have been shown to participate in numerous pregnancy-related events. In this review, we summarize the literature data regarding their role in healthy and pathological pregnancies. The general information related to IL-6 and IL-8 functions is followed by an overview of their overall expression in cycling endometrium and at the feto-maternal interface. Further, we provide an overview of their involvement in pregnancy establishment and parturition. Finally, the implication of IL-6 and IL-8 in pregnancy-associated pathological conditions, such as pregnancy loss, preeclampsia, gestational diabetes mellitus and infection/inflammation is discussed.

Granulocyte Colony-Stimulating Factor Improved Core Symptoms of Autism Spectrum Disorder via Modulating Glutamatergic Receptors in the Prefrontal Cortex and Hippocampus of Rat Brains

Chronic neuroinflammation-induced anomalous glutamate receptor activation has been identified as one of the important factors in the pathogenesis of autism spectrum disorder (ASD). Thus, the current study was designed to elucidate the neuroprotective effect of the granulocyte colony-stimulating factor (G-CSF), a haemopoietic growth factor, an anti-inflammatory, and a neuroprotectant to decipher the underlying mechanism(s) in the valproic acid (VPA)-induced experimental model of ASD. Experimentally, the ASD rat model was induced by a single dose of VPA (600 mg/kg; i.p.) on gestation day 12.5 to the pregnant female rats. After birth, pups were treated with vehicle, normal saline 0.9% i.p., risperidone (2.5 mg/kg; i.p.), and G-CSF (10, 35, and 70 μg/kg; i.p.) from postnatal day (PND) 23 to 43. All the groups were subjected to various developmental and behavior tests from birth. The rats were sacrificed on PND 55, and their brain was excised and processed for biochemical parameters (oxidative stress, inflammatory markers, BDNF), histological examination (H&E, Nissl staining), NMDA, and AMPA receptor expression by immunohistochemistry, western blot, and real-time polymerase chain reaction evaluation. Also, the possible interaction of the G-CSF with NMDA and AMPA receptors was evaluated using the in-silico method. The results of the study showed that in VPA-exposed rats, postnatal treatment of G-CSF rescued all the behavioral abnormalities, oxidative stress, and inflammatory parameters in a dose-dependent manner while risperidone did not show any significant results. The in-silico analysis showed the direct interaction of G-CSF with NMDA and AMPA receptors. The upregulated expression of NMDA and AMPA both in the prefrontal cortex as well as hippocampus was alleviated by G-CSF thereby validating its anti-inflammatory and excitoprotective properties. Thus, G-CSF demonstrated neuroprotection against the core symptoms of autism in the VPA-induced rodent model, making it a potential candidate for the treatment of ASD.

Chemical Modulators for Targeting Autism Spectrum Disorders: From Bench to Clinic

Autism spectrum disorders (ASD) are neurodevelopmental disorders characterized by diverse behavioral symptoms such as repetitive behaviors, social deficits, anxiety, hyperactivity, and irritability. Despite their increasing incidence, the specific pathological mechanisms of ASD are still unknown, and the degree and types of symptoms that vary from patient to patient make it difficult to develop drugs that target the core symptoms of ASD. Although various atypical antipsychotics and antidepressants have been applied to regulate ASD symptoms, these drugs can only alleviate the symptoms and do not target the major causes. Therefore, development of novel drugs targeting factors directly related to the onset of ASD is required. Among the various factors related to the onset of ASD, several chemical modulators to treat ASD, focused on serotonin (5-hydroxytryptamine, 5-HT) and glutamate receptors, microbial metabolites, and inflammatory cytokines, are explored in this study. In particular, we focus on the chemical drugs that have improved various aspects of ASD symptoms in animal models and in clinical trials for various ages of patients with ASD.

Immune-Triggered Forms of Plasticity Across Brain Regions

Immune cells play numerous roles in the host defense against the invasion of microorganisms and pathogens, which induces the release of inflammatory mediators (e.g., cytokines and chemokines). In the CNS, microglia is the major resident immune cell. Recent efforts have revealed the diversity of the cell types and the heterogeneity of their functions. The refinement of the synapse structure was a hallmark feature of the microglia, while they are also involved in the myelination and capillary dynamics. Another promising feature is the modulation of the synaptic transmission as synaptic plasticity and the intrinsic excitability of neurons as non-synaptic plasticity. Those modulations of physiological properties of neurons are considered induced by both transient and chronic exposures to inflammatory mediators, which cause behavioral disorders seen in mental illness. It is plausible for astrocytes and pericytes other than microglia and macrophage to induce the immune-triggered plasticity of neurons. However, current understanding has yet achieved to unveil what inflammatory mediators from what immune cells or glia induce a form of plasticity modulating pre-, post-synaptic functions and intrinsic excitability of neurons. It is still unclear what ion channels and intracellular signaling of what types of neurons in which brain regions of the CNS are involved. In this review, we introduce the ubiquitous modulation of the synaptic efficacy and the intrinsic excitability across the brain by immune cells and related inflammatory cytokines with the mechanism for induction. Specifically, we compare neuro-modulation mechanisms by microglia of the intrinsic excitability of cerebellar Purkinje neurons with cerebral pyramidal neurons, stressing the inverted directionality of the plasticity. We also discuss the suppression and augmentation of the extent of plasticity by inflammatory mediators, as the meta-plasticity by immunity. Lastly, we sum up forms of immune-triggered plasticity in the different brain regions with disease relevance. Together, brain immunity influences our cognition, sense, memory, and behavior via immune-triggered plasticity.

Therapeutic Effects of a Novel Form of Biotin on Propionic Acid-Induced Autistic Features in Rats

Magnesium biotinate (MgB) is a novel biotin complex with superior absorption and anti-inflammatory effects in the brain than D-Biotin. This study aimed to investigate the impact of different doses of MgB on social behavior deficits, learning and memory alteration, and inflammatory markers in propionic acid (PPA)-exposed rats. In this case, 35 Wistar rats (3 weeks old) were distributed into five groups: 1, Control; 2, PPA treated group; 3, PPA+MgBI (10 mg, HED); 4, PPA+MgBII (100 mg, HED); 5, PPA+MgBIII (500 mg, HED). PPA was given subcutaneously at 500 mg/kg/day for five days, followed by MgB for two weeks. PPA-exposed rats showed poor sociability and a high level of anxiety-like behaviors and cognitive impairments (p < 0.001). In a dose-dependent manner, behavioral and learning-memory disorders were significantly improved by MgB supplementation (p < 0.05). PPA decreased both the numbers and the sizes of Purkinje cells in the cerebellum. However, MgB administration increased the sizes and the densities of Purkinje cells. MgB improved the brain and serum Mg, biotin, serotonin, and dopamine concentrations, as well as antioxidant enzymes (CAT, SOD, GPx, and GSH) (p < 0.05). In addition, MgB treatment significantly regulated the neurotoxicity-related cytokines and neurotransmission-related markers. For instance, MgB significantly decreased the expression level of TNF-α, IL-6, IL-17, CCL-3, CCL-5, and CXCL-16 in the brain, compared to the control group (p < 0.05). These data demonstrate that MgB may ameliorate dysfunctions in social behavior, learning and memory and reduce the oxidative stress and inflammation indexes of the brain in a rat model.

Dynamic and Systemic Perspective in Autism Spectrum Disorders: A Change of Gaze in Research Opens to A New Landscape of Needs and Solutions

The first step for a harmonious bio-psycho-social framework in approaching autism spectrum disorders (ASD) is overcoming the conflict between the biological and the psychosocial perspective. Biological research can provide clues for a correct approach to clinical practice, assuming that it would lead to the conceptualization of a pathogenetic paradigm able to account for epidemiologic and clinical findings. The upward trajectory in ASD prevalence and the systemic involvement of other organs besides the brain suggest that the epigenetic paradigm is the most plausible one. The embryo-fetal period is the crucial window of opportunity for keeping neurodevelopment on the right tracks, suggesting that women's health in pregnancy should be a priority. Maladaptive molecular pathways beginning in utero, in particular, a vicious circle between the immune response, oxidative stress/mitochondrial dysfunction, and dysbiosis-impact neurodevelopment and brain functioning across the lifespan and are the basis for progressive multisystemic disorders that account for the substantial health loss and the increased mortality in ASD. Therefore, the biological complexity of ASD and its implications for health requires the enhancement of clinical skills on these topics, to achieve an effective multi-disciplinary healthcare model. Well-balanced training courses could be a promising starting point to make a change.

Maternal Immune Activation and Interleukin 17A in the Pathogenesis of Autistic Spectrum Disorder and Why It Matters in the COVID-19 Era

Autism spectrum disorder (ASD) is the commonest neurodevelopmental disability. It is a highly complex disorder with an increasing prevalence and an unclear etiology. Consensus indicates that ASD arises as a genetically modulated, and environmentally influenced condition. Although pathogenic rare genetic variants are detected in around 20% of cases of ASD, no single factor is responsible for the vast majority of ASD cases or that explains their characteristic clinical heterogeneity. However, a growing body of evidence suggests that ASD susceptibility involves an interplay between genetic factors and environmental exposures. One such environmental exposure which has received significant attention in this regard is maternal immune activation (MIA) resulting from bacterial or viral infection during pregnancy. Reproducible rodent models of ASD are well-established whereby induction of MIA in pregnant dams, leads to offspring displaying neuroanatomical, functional, and behavioral changes analogous to those seen in ASD. Blockade of specific inflammatory cytokines such as interleukin-17A during gestation remediates many of these observed behavioral effects, suggesting a causative or contributory role. Here, we review the growing body of animal and human-based evidence indicating that interleukin-17A may mediate the observed effects of MIA on neurodevelopmental outcomes in the offspring. This is particularly important given the current corona virus disease-2019 (COVID-19) pandemic as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during pregnancy is a potent stimulator of the maternal immune response, however the long-term effects of maternal SARS-CoV-2 infection on neurodevelopmental outcomes is unclear. This underscores the importance of monitoring neurodevelopmental outcomes in children exposed to SARS-CoV-2-induced MIA during gestation.

Potential Neurocognitive Symptoms Due to Respiratory Syncytial Virus Infection

Respiratory infections are among the major public health burdens, especially during winter. Along these lines, the human respiratory syncytial virus (hRSV) is the principal viral agent causing acute lower respiratory tract infections leading to hospitalization. The pulmonary manifestations due to hRSV infection are bronchiolitis and pneumonia, where the population most affected are infants and the elderly. However, recent evidence suggests that hRSV infection can impact the mother and fetus during pregnancy. Studies have indicated that hRSV can infect different cell types from the placenta and even cross the placenta barrier and infect the fetus. In addition, it is known that infections during the gestational period can lead to severe consequences for the development of the fetus due not only to a direct viral infection but also because of maternal immune activation (MIA). Furthermore, it has been described that the development of the central nervous system (CNS) of the fetus can be affected by the inflammatory environment of the uterus caused by viral infections. Increasing evidence supports the notion that hRSV could invade the CNS and infect nervous cells, such as microglia, neurons, and astrocytes, promoting neuroinflammation. Moreover, it has been described that the hRSV infection can provoke neurological manifestations, including cognitive impairment and behavioral alterations. Here, we will review the potential effect of hRSV in brain development and the potential long-term neurological sequelae.

New concepts in the development of schizophrenia, autism spectrum disorders, and degenerative brain diseases based on chronic inflammation: A working hypothesis from continued advances in neuroscience research

This paper was written prompted by a poignant film about adolescent girl with schizophrenia who babysits for a younger girl in an isolated cabin. Schizophrenia is an illness that both authors are fascinated with and that they continue to study and investigate. There is now compelling evidence that schizophrenia is a very complex syndrome that involves numerous neural pathways in the brain, far more than just dopaminergic and serotonergic systems. One of the more popular theories in recent literature is that it represents a hypo glutaminergic deficiency of certain pathways, including thalamic ones. After much review of research and study in this area, we have concluded that most such theories contain a number of shortcomings. Most are based on clinical responses to certain drugs, particularly antipsychotic drugs affecting the dopaminergic neurotransmitters; thus, assuming dopamine release was the central cause of the psychotic symptoms of schizophrenia. The theory was limited in that dopamine excess could only explain the positive symptoms of the disorder. Antipsychotic medications have minimal effectiveness for the negative and cognitive symptoms associated with schizophrenia. It has been estimated that 20–30% of patients show either a partial or no response to antipsychotic medications. In addition, the dopamine hypothesis does not explain the neuroanatomic findings in schizophrenia.

Covid-19 pandemic: What is the truth?

The ongoing “pandemic” involving the severe acute respiratory syndrome coronavirus 2 virus (SARS-CoV-2) has several characteristics that make it unique in the history of pandemics. This entails not only the draconian measures that some countries and individual states within the United States and initiated and made policy, most of which are without precedent or scientific support, but also the completely unscientific way the infection has been handled. For the 1^st time in medical history, major experts in virology, epidemiology, infectious diseases, and vaccinology have not only been ignored, but are also demonized, marginalized and in some instances, become the victim of legal measures that can only be characterized as totalitarian. Discussions involving various scientific opinions have been eliminated, top scientists have been frightened into silence by threats to their careers, physicians have lost their licenses, and the concept of early treatment has been virtually eliminated. Hundreds of thousands of people have died needlessly as a result of, in my opinion and the opinion of others, poorly designed treatment protocols, mostly stemming from the Center for Disease Control and Prevention, which have been rigidly enforced among all hospitals. The economic, psychological, and institutional damage caused by these unscientific policies is virtually unmeasurable. Whole generations of young people will suffer irreparable damage, both physical and psychological, possibly forever. The truth must be told.

Maternal immune-related conditions during pregnancy may be a risk factor for neuropsychiatric problems in offspring throughout childhood and adolescence

BACKGROUND

Emerging research suggests that maternal immune activation (MIA) may be associated with an increased risk of adverse neurodevelopmental and mental health outcomes in offspring. Using data from the Raine Study, we investigated whether MIA during pregnancy was associated with increased behavioral and emotional problems in offspring longitudinally across development.

METHODS

Mothers (Generation 1; N = 1905) were classified into the following categories: AAAE (Asthma/Allergy/Atopy/Eczema; N = 1267); infection (during pregnancy; N = 1082); no AAAE or infection (N = 301). The Child Behavior Checklist (CBCL) was administered for offspring at ages 5, 8, 10, 14, and 17. Generalized estimating equations were used to investigate the effect of maternal immune status on CBCL scores.

RESULTS

AAAE conditions were associated with significant increases in CBCL Total (β 2.49; CI 1.98-3.00), Externalizing (β 1.54; CI 1.05-2.03), and Internalizing (β 2.28; CI 1.80-2.76) scores. Infection conditions were also associated with increased Total (β 1.27; CI 0.77-1.78), Externalizing (β 1.18; CI 0.70-1.66), and Internalizing (β 0.76; CI 0.28-1.24) scores. Exposure to more than one AAAE and/or infection condition was associated with a greater elevation in CBCL scores than single exposures in males and females. Females showed greater increases on the Internalizing scale from MIA, while males showed similar increases on both Internalizing and Externalizing scales.

CONCLUSIONS

MIA was associated with increased behavioral and emotional problems in offspring throughout childhood and adolescence. This highlights the need to understand the relationship between MIA, fetal development, and long-term outcomes, with the potential to advance early identification and intervention strategies.

Mid-gestation cytokine profiles in mothers of children affected by autism spectrum disorder: a case-control study

Autism Spectrum disorder is one of the commonest and most important neurodevelopmental conditions affecting children today. With an increasing prevalence and an unclear aetiology, it is imperative we find early markers of autism, which may facilitate early identification and intervention. Alterations of gestational cytokine profiles have been reported in mothers of autistic children. Increasing evidence suggests that the intrauterine environment is an important determinant of autism risk. This study aims to examine the mid-gestational serum cytokine profiles of the mothers of autistic children from a well-characterised birth cohort. A nested sub-cohort within a large mother-child birth cohort were identified based on a confirmed multi-disciplinary diagnosis of autism before the age 10 years and neuro-typical matched controls in a 2:1 ratio. IFN-γ, IL-1β, IL-4, IL-6, IL-8, IL-17A, GMCSF and TNFα were measured in archived maternal 20-week serum using MesoScale Diagnostics multiplex technology and validation of our IL-17A measurements was performed using an ultrasensitive assay. From a cohort of 2137 children, 25 had confirmed autism before 10 years and stored maternal serum from mid-gestation. We examined the sera of these 25 cases and 50 matched controls. The sex ratio was 4:1 males to females in each group, and the mean age at diagnosis was 5.09 years (SD 2.13). We found that concentrations of IL-4 were significantly altered between groups. The other analytes did not differ significantly using either multiplex or ultra-sensitive assays. In our well-characterised prospective cohort of autistic children, we confirmed mid-gestational alterations in maternal IL-4 concentrations in autism affected pregnancies versus matched controls. These findings add to promising evidence from animal models and retrospective screening programmes and adds to the knowledge in this field.

The Role of Maternal Immune Activation in the Pathogenesis of Autism: A Review of the Evidence, Proposed Mechanisms and Implications for Treatment

Autism spectrum disorder (ASD) is a neurodevelopmental disease that is characterized by a deficit in social interactions and communication, as well as repetitive and restrictive behaviors. Increasing lines of evidence suggest an important role for immune dysregulation and/or inflammation in the development of ASD. Recently, a relationship between inflammation, oxidative stress, and mitochondrial dysfunction has been reported in the brain tissue of individuals with ASD. Some recent studies have also reported oxidative stress and mitochondrial abnormalities in animal models of maternal immune activation (MIA). This review is focused on the hypothesis that MIA induces microglial activation, oxidative stress, and mitochondrial dysfunction, a deleterious trio in the brain that can lead to neuroinflammation and neurodevelopmental pathologies in offspring. Infection during pregnancy activates the mother’s immune system to release proinflammatory cytokines, such as IL-6, TNF-α, and others. Furthermore, these cytokines can directly cross the placenta and enter the fetal circulation, or activate resident immune cells, resulting in an increased production of proinflammatory cytokines, including IL-6. Proinflammatory cytokines that cross the blood–brain barrier (BBB) may initiate a neuroinflammation cascade, starting with the activation of the microglia. Inflammatory processes induce oxidative stress and mitochondrial dysfunction that, in turn, may exacerbate oxidative stress in a self-perpetuating vicious cycle that can lead to downstream abnormalities in brain development and behavior.

Cytokines profile in neonatal and adult wild-type mice post-injection of U. S. pediatric vaccination schedule

Introduction

A recent study from our laboratory demonstrated a number of neurobehavioral abnormalities in mice colony injected with a mouse-weight equivalent dose of all vaccines that are administered to infants in their first 18 months of life according to the U. S. pediatric vaccination schedule.

Cytokines have been studied extensively as blood immune and inflammatory biomarkers, and their association with neurodevelopmental disorders. Given the importance of cytokines in early neurodevelopment, we aimed to investigate the potential post-administration effects of the U. S. pediatric vaccines on circulatory cytokines in a mouse model.

In the current study, cytokines have been assayed at early and late time points in mice vaccinated early in postnatal life and compared with placebo controls.

Materials and methods

Newborn mouse pups were divided into three groups: i) vaccine (V1), ii) vaccine ​× ​3 (V3) and iii) placebo control. V1 group was injected with mouse weight-equivalent of the current U. S. pediatric vaccine schedule. V3 group was injected with same vaccines but at triple the dose and the placebo control was injected with saline. Pups were also divided according to the sampling age into two main groups: acute- and chronic-phase group. Blood samples were collected at postnatal day (PND) 23, two days following vaccine schedule for the acute-phase group or at 67 weeks post-vaccination for the chronic-phase groups. Fifteen cytokines were analyzed: GM-CSF, IFN-γ, IL-1β, IL-2, IL-4, IL-5, IL-6, IL-9, IL-10, IL-12p70, IL-13, IL-17A, MCP-1, TNF-α, and VEGF-A. Wilcoxon Rank Sum test or unpaired Student's t-test was performed where applicable.

Results

IL-5 levels in plasma were significantly elevated in the V1 and V3 group compared with the control only in the acute-phase group. The elevation of IL-5 levels in the two vaccine groups were significant irrespective of whether the sexes were combined or analyzed separately. Other cytokines (VEGF-A, TNF-α, IL-10, MCP-1, GM-CSF, IL-6, and IL-13) were also impacted, although to a lesser extent and in a sex-dependent manner. In the acute-phase group, females showed a significant increase in IL-10 and MCP-1 levels and a decrease in VEGF-A levels in both V1 and V3 group compared to controls. In the acute-phase, a significant increase in MCP-1 levels in V3 group and CM-CSF levels in V1 and V3 group and decrease in TNF-α levels in V1 group were observed in treated males as compared with controls. In chronic-phase females, levels of VEGF-A in V1 and V3 group, TNF-α in V3 group, and IL-13 in V1 group were significantly decreased in contrast with controls. In chronic-phase males, TNF-α levels were significantly increased in V1 group and IL-6 levels decreased in V3 group in comparison to controls. The changes in levels of most tested cytokines were altered between the early and the late postnatal assays.

Conclusions

IL-5 levels significantly increased in the acute-phase of the treatment in the plasma of both sexes that were subjected to V1 and V3 injections. These increases had diminished by the second test assayed at week 67. These results suggest that a profound, albeit transient, effect on cytokine levels may be induced by the whole vaccine administration supporting our recently published observations regarding the behavioral abnormalities in the same mice. These observations support the view that the administration of whole pediatric vaccines in a neonatal period may impact at least short-term CNS functions in mice.

Maternal Mid-Gestation Cytokine Dysregulation in Mothers of Children with Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a developmental disorder characterised by deficits in social interactions and communication, with stereotypical and repetitive behaviours. Recent evidence suggests that maternal immune dysregulation may predispose offspring to ASD. Independent samples t-tests revealed downregulation of IL-17A concentrations in cases, when compared to controls, at both 15 weeks (p = 0.02), and 20 weeks (p = 0.02), which persisted at 20 weeks following adjustment for confounding variables. This adds to the growing body of evidence that maternal immune regulation may play a role in foetal neurodevelopment.

Maternal Interleukin-6 Is Associated With Macaque Offspring Amygdala Development and Behavior

Human and animal cross-sectional studies have shown that maternal levels of the inflammatory cytokine interleukin-6 (IL-6) may compromise brain phenotypes assessed at single time points. However, how maternal IL-6 associates with the trajectory of brain development remains unclear. We investigated whether maternal IL-6 levels during pregnancy relate to offspring amygdala volume development and anxiety-like behavior in Japanese macaques. Magnetic resonance imaging (MRI) was administered to 39 Japanese macaque offspring (Female: 18), providing at least one or more time points at 4, 11, 21, and 36 months of age with a behavioral assessment at 11 months of age. Increased maternal third trimester plasma IL-6 levels were associated with offspring's smaller left amygdala volume at 4 months, but with more rapid amygdala growth from 4 to 36 months. Maternal IL-6 predicted offspring anxiety-like behavior at 11 months, which was mediated by reduced amygdala volumes in the model's intercept (i.e., 4 months). The results increase our understanding of the role of maternal inflammation in the development of neurobehavioral disorders by detailing the associations of a commonly examined inflammatory indicator, IL-6, on amygdala volume growth over time, and anxiety-like behavior.

Rescue of maternal immune activation-induced behavioral abnormalities in adult mouse offspring by pathogen-activated maternal Treg cells

Maternal immune activation (MIA) induced by lipopolysaccharides or polyinosinic:polycytidylic acid injections can induce behavioral abnormalities in adult mouse offspring. Here, we used the soluble tachyzoite antigen from Toxoplasma gondii, a parasite that infects approximately two billion people, to induce MIA in mice. The adult male offspring showed autism-relevant behaviors and abnormal brain microstructure, along with a pro-inflammatory T-cell immune profile in the periphery and upregulation of interleukin-6 in brain astrocytes. We show that adoptive transfer of regulatory T (T_reg) cells largely reversed these MIA-induced phenotypes. Notably, pathogen-activated maternal T_reg cells showed greater rescue efficacy than those from control donors. Single-cell RNA sequencing identified and characterized a unique group of pathogen-activated T_reg cells that constitute 32.6% of the pathogen-activated maternal T_reg population. Our study establishes a new preclinical parasite-mimicking MIA model and suggests therapeutic potential of adoptive T_reg cell transfer in neuropsychiatric disorders associated with immune alterations.

Microbiota and Microglia Interactions in ASD

Autism spectrum disorders (ASD) are serious, highly variable neurodevelopmental disorders, commonly characterized by the manifestation of specific behavioral abnormalities, such as stereotypic behaviors and deficits in social skills, including communication. Although the neurobiological basis for ASD has attracted attention in recent decades, the role of microglial cells, which are the main resident myeloid cell population in the brain, is still controversial and underexplored. Microglia play several fundamental roles in orchestrating brain development and homeostasis. As such, alterations in the intrinsic functions of these cells could be one of the driving forces responsible for the development of various neurodevelopmental disorders, including ASD. Microglia are highly sensitive to environmental cues. Amongst the environmental factors known to influence their intrinsic functions, the gut microbiota has emerged as a central player, controlling both microglial maturation and activation. Strikingly, there is now compelling data suggesting that the intestinal microbiota can play a causative role in driving the behavioural changes associated with ASD. Not only is intestinal dysbiosis commonly reported in ASD patients, but therapies targeting the microbiome can markedly alleviate behavioral symptoms. Here we explore the emerging mechanisms by which altered microglial functions could contribute to several major etiological factors of ASD. We then demonstrate how pre- and postnatal environmental stimuli can modulate microglial cell phenotype and function, underpinning the notion that reciprocal interactions between microglia and intestinal microbes could play a crucial role in ASD aetiology.

Autism Spectrum Disorder from the Womb to Adulthood: Suggestions for a Paradigm Shift

The wide spectrum of unique needs and strengths of Autism Spectrum Disorders (ASD) is a challenge for the worldwide healthcare system. With the plethora of information from research, a common thread is required to conceptualize an exhaustive pathogenetic paradigm. The epidemiological and clinical findings in ASD cannot be explained by the traditional linear genetic model, hence the need to move towards a more fluid conception, integrating genetics, environment, and epigenetics as a whole. The embryo-fetal period and the first two years of life (the so-called 'First 1000 Days') are the crucial time window for neurodevelopment. In particular, the interplay and the vicious loop between immune activation, gut dysbiosis, and mitochondrial impairment/oxidative stress significantly affects neurodevelopment during pregnancy and undermines the health of ASD people throughout life. Consequently, the most effective intervention in ASD is expected by primary prevention aimed at pregnancy and at early control of the main effector molecular pathways. We will reason here on a comprehensive and exhaustive pathogenetic paradigm in ASD, viewed not just as a theoretical issue, but as a tool to provide suggestions for effective preventive strategies and personalized, dynamic (from womb to adulthood), systemic, and interdisciplinary healthcare approach.

Critical Role of the Maternal Immune System in the Pathogenesis of Autism Spectrum Disorder

Autism spectrum disorders (ASD) are a group of neurodevelopmental disorders characterised by impairments in communication, social interaction, and the presence of restrictive and repetitive behaviours. Over the past decade, most of the research in ASD has focused on the contribution of genetics, with the identification of a variety of different genes and mutations. However, the vast heterogeneity in clinical presentations associated with this disorder suggests that environmental factors may be involved, acting as a “second hit” in already genetically susceptible individuals. To this regard, emerging evidence points towards a role for maternal immune system dysfunctions. This literature review considered evidence from epidemiological studies and aimed to discuss the pathological relevance of the maternal immune system in ASD by looking at the proposed mechanisms by which it alters the prenatal environment. In particular, this review focuses on the effects of maternal immune activation (MIA) by looking at foetal brain-reactive antibodies, cytokines and the microbiome. Despite the arguments presented here that strongly implicate MIA in the pathophysiology of ASD, further research is needed to fully understand the precise mechanisms by which they alter brain structure and behaviour. Overall, this review has not only shown the importance of the maternal immune system as a risk factor for ASD, but more importantly, has highlighted new promising pathways to target for the discovery of novel therapeutic interventions for the treatment of such a life-changing disorder.

Maternal immune conditions are increased in males with autism spectrum disorders and are associated with behavioural and emotional but not cognitive co-morbidity

Epidemiological and animal research shows that maternal immune activation increases the risk of autism spectrum disorders (ASD) in offspring. Emerging evidence suggests that maternal immune conditions may play a role in the phenotypic expression of neurodevelopmental difficulties in children with ASD and this may be moderated by offspring sex. This study aimed to investigate whether maternal immune conditions were associated with increased severity of adverse neurodevelopmental outcomes in children with ASD. Maternal immune conditions were examined as predictors of ASD severity, behavioural and emotional well-being, and cognitive functioning in a cohort of 363 children with ASD (n = 363; 252 males, 111 females; median age 3.07 [interquartile range 2.64-3.36 years]). We also explored whether these outcomes varied between male and female children. Results showed that maternal asthma was the most common immune condition reported in mothers of children with ASD. A history of maternal immune conditions (p = 0.009) was more common in male children with ASD, compared to female children. Maternal immune conditions were associated with increased behavioural and emotional problems in male and female children. By contrast, maternal immune conditions were not associated with decreased cognitive function. The findings demonstrate that MIA may influence the expression of symptoms in children with ASD and outcomes may vary between males and females.

Perinatal Opioid Exposure Primes the Peripheral Immune System Toward Hyperreactivity

The increased incidence of opioid use during pregnancy warrants investigation to reveal the impact of opioid exposure on the developing fetus. Exposure during critical periods of development could have enduring consequences for affected individuals. Particularly, evidence is mounting that developmental injury can result in immune priming, whereby subsequent immune activation elicits an exaggerated immune response. This maladaptive hypersensitivity to immune challenge perpetuates dysregulated inflammatory signaling and poor health outcomes. Utilizing an established preclinical rat model of perinatal methadone exposure, we sought to investigate the consequences of developmental opioid exposure on in vitro activation of peripheral blood mononuclear cells (PBMCs). We hypothesize that PBMCs from methadone-exposed rats would exhibit abnormal chemokine and cytokine expression at baseline, with exaggerated chemokine and cytokine production following immune stimulation compared to saline-exposed controls. On postnatal day (P) 7, pup PMBCs were isolated and cultured, pooling three pups per n. Following 3 and 24 h, the supernatant from cultured PMBCs was collected and assessed for inflammatory cytokine and chemokine expression at baseline or lipopolysaccharide (LPS) stimulation using multiplex electrochemiluminescence. Following 3 and 24 h, baseline production of proinflammatory chemokine and cytokine levels were significantly increased in methadone PBMCs (p < 0.0001). Stimulation with LPS for 3 h resulted in increased tumor necrosis factor (TNF-α) and C-X-C motif chemokine ligand 1 (CXCL1) expression by 3.5-fold in PBMCs from methadone-exposed PBMCs compared to PBMCs from saline-exposed controls (p < 0.0001). Peripheral blood mononuclear cell hyperreactivity was still apparent at 24 h of LPS stimulation, evidenced by significantly increased TNF-α, CXCL1, interleukin 6 (IL-6), and IL-10 production by methadone PMBCs compared to saline control PBMCs (p < 0.0001). Together, we provide evidence of increased production of proinflammatory molecules from methadone PBMCs at baseline, in addition to sustained hyperreactivity relative to saline-exposed controls. Exaggerated peripheral immune responses exacerbate inflammatory signaling, with subsequent consequences on many organ systems throughout the body, such as the developing nervous system. Enhanced understanding of these inflammatory mechanisms will allow for appropriate therapeutic development for infants who were exposed to opioids during development. Furthermore, these data highlight the utility of this in vitro PBMC assay technique for future biomarker development to guide specific treatment for patients exposed to opioids during gestation.

Maternal Immune Activation Alters Fetal Brain Development and Enhances Proliferation of Neural Precursor Cells in Rats

Maternal immune activation (MIA) caused by exposure to pathogens or inflammation during critical periods of neurodevelopment is a major risk factor for behavioral deficits and psychiatric illness in offspring. A spectrum of behavioral abnormalities can be recapitulated in rodents by inducing MIA using the viral mimetic, PolyI:C. Many studies have focused on long-term changes in brain structure and behavioral outcomes in offspring following maternal PolyI:C exposure, but acute changes in prenatal development are not well-characterized. Using RNA-Sequencing, we profiled acute transcriptomic changes in rat conceptuses (decidua along with nascent embryo and placenta) after maternal PolyI:C exposure during early gestation, which enabled us to capture gene expression changes provoked by MIA inclusive to the embryonic milieu. We identified a robust increase in expression of genes related to antiviral inflammation following maternal PolyI:C exposure, and a corresponding decrease in transcripts associated with nervous system development. At mid-gestation, regions of the developing cortex were thicker in fetuses prenatally challenged with PolyI:C, with females displaying a thicker ventricular zone and males a thicker cortical mantle. Along these lines, neural precursor cells (NPCs) isolated from fetal brains prenatally challenged with PolyI:C exhibited a higher rate of self-renewal. Expression of Notch1 and the Notch ligand, delta-like ligand 1, which are both highly implicated in maintenance of NPCs and nervous system development, was increased following PolyI:C exposure. These results suggest that MIA elicits rapid gene expression changes within the conceptus, including repression of neurodevelopmental pathways, resulting in profound alterations in fetal brain development.

Maternal Immune Activation Induces Neuroinflammation and Cortical Synaptic Deficits in the Adolescent Rat Offspring

Maternal immune activation (MIA), induced by infection during pregnancy, is an important risk factor for neuro-developmental disorders, such as autism. Abnormal maternal cytokine signaling may affect fetal brain development and contribute to neurobiological and behavioral changes in the offspring. Here, we examined the effect of lipopolysaccharide-induced MIA on neuro-inflammatory changes, as well as synaptic morphology and key synaptic protein level in cerebral cortex of adolescent male rat offspring. Adolescent MIA offspring showed elevated blood cytokine levels, microglial activation, increased pro-inflammatory cytokines expression and increased oxidative stress in the cerebral cortex. Moreover, pathological changes in synaptic ultrastructure of MIA offspring was detected, along with presynaptic protein deficits and down-regulation of postsynaptic scaffolding proteins. Consequently, ability to unveil MIA-induced long-term alterations in synapses structure and protein level may have consequences on postnatal behavioral changes, associated with, and predisposed to, the development of neuropsychiatric disorders.

Involvement of CD45 cells in the development of autism spectrum disorder through dysregulation of granulocyte-macrophage colony-stimulating factor, key inflammatory cytokines, and transcription factors

Autismspectrum disorder (ASD) is a complex and multifactorial heterogeneous disorder. Previous investigations have revealed the association between the immune system and ASD, which is characterized by impaired communication skills. Inflammatory response through CD45 cells plays a key role in the pathogenesis of several autoimmune disorders; however, the molecular mechanism of CD45 cells in ASD is not clearly defined.In this study, we investigated the role of CD45 signaling in children with ASD. In this study, we aimed to investigate the possible involvement of CD45 cells expressing granulocyte-macrophage colony-stimulating factor and inflammatory transcription factors in ASD. Flow cytometric analysis, using peripheral blood mononuclear cells (PBMC), revealed the numbers of GM-CSF-, IFN-γ-, IL-6-, IL-9-, IL-22-, T-bet-, pStat3-, Helios-, and Stat6-producing CD45⁺ cells in children with ASD and children in the control group. We further evaluated the mRNA and protein expression levels of GM-CSF in PBMC by RT-PCR and western blotting analysis. Our results revealed that the children with ASD exhibited significantly higher numbers of CD45⁺GM-CSF⁺, CD45⁺IFN-γ⁺, CD45⁺IL-6⁺, CD45⁺IL-9⁺, CD45⁺IL-22⁺, CD45⁺T-bet⁺, and CD45⁺pStat3⁺ cells compared with the control group. We also found that the children with ASD showed a lower number of CD45⁺Helios⁺ and CD45⁺Stat6⁺ cells compared with the control group. Furthermore, the children with ASD showed higher GM-CSF mRNA and protein expression levels compared with the control group. These results indicated that CD45 could play an essential role in the immune abnormalities of ASD. Further investigation of the role of CD45 in neurodevelopment in ASD is warranted.

Gut microbiota changes in children with autism spectrum disorder: a systematic review

BACKGROUND

As more animal studies start to disentangle pathways linking the gut microbial ecosystem and neurobehavioral traits, human studies have grown rapidly. Many have since investigated the bidirectional communication between the gastrointestinal tract and the central nervous system, specifically on the effects of microbial composition on the brain and development.

METHODS

Our review at the initial stage aimed to evaluate literature on gut microbial alterations in pediatric neurobehavioral conditions. We searched five literature databases (Embase, PubMed, PsychInfo, Scopus, and Medline) and found 4489 published work. As the mechanisms linking gut microbiota to these conditions are divergent, the scope of this review was narrowed to focus on describing gut dysbiosis in children with autism spectrum disorder (ASD).

RESULTS

Among the final 26 articles, there was a lack of consistency in the reported gut microbiome changes across ASD studies, except for distinguishable patterns, within limits, for Prevotella, Firmicutes at the phylum level, Clostridiales clusters including Clostridium perfringens, and Bifidobacterium species.

CONCLUSIONS

These results were inadequate to confirm a global microbiome change in children with ASD and causality could not be inferred to explain the etiology of the behaviors associated with ASD. Mechanistic studies are needed to elucidate the specific role of the gut microbiome in the pathogenesis of ASD.

Maternal immune activation modifies the course of Niemann-pick disease, type C1 in a gender specific manner

Niemann-Pick disease, type C1 (NPC1) is a rare neurodegenerative lysosomal storage disease with a wide spectrum of clinical manifestation. Multiple genetic factors influence the NPC1 mouse phenotype, but very little attention has been given to prenatal environmental factors that might have long-term effects on the neuroinflammatory component of NPC1 pathology. Studies in other mouse models of cerebellar ataxia have shown that developmental exposures lead to Purkinje neuron degeneration later in life, suggesting that environmental exposures during development can impact cerebellar biology. Thus, we evaluated the potential effect of maternal immune activation (MIA) on disease progression in an Npc1 mouse model. The MIA paradigm used mimics viral infection using the toll like receptor 3 agonist polyinosinic-polycytidilic acid during gestation. Through phenotypic and pathologic tests, we measured motor and behavioral changes as well as cerebellar neuroinflammation and neurodegeneration. We observed a gender and genotype dependent effect of MIA on the cerebellum. While the effects of MIA have been previously shown to primarily affect male progeny, we observed increased sensitivity of female mutant progeny to prenatal exposure to treatment with polyinosinic-polycytidilic acid. Specifically, prenatal MIA resulted in female NPC1 mutant progeny with greater motor deficits and a corresponding decrease in cerebellar Purkinje neurons. Our data suggest that prenatal environmental exposures may be one factor contributing to the phenotypic variability observed in individuals with NPC1.

Therapeutic efficacy of environmental enrichment on behavioral, endocrine, and synaptic alterations in an animal model of maternal immune activation

Maternal immune activation (MIA) has been identified as a significant risk factor for several neurodevelopmental disorders. We have previously demonstrated that postpubertal environmental enrichment (EE) rescues and promotes resiliency against MIA in male rats. Importantly, EE protocols have demonstrated clinical relevancy in human rehabilitation settings. Applying some of the elements of these EE protocols (e.g. social, physical, cognitive stimulation) to animal models of health and disease allows for the exploration of the mechanisms that underlie their success. Here, using a MIA model, we further investigate the rehabilitative potential of complex environments with a focus on female animals. Additionally, we expand upon some of our previous work by exploring genetic markers of synaptic plasticity and stress throughout several brain regions of both sexes. In the current study, standard housed female Sprague-Dawley rats were challenged with either the inflammatory endotoxin lipopolysaccharide (LPS; 100 μg/kg) or saline (equivolume) on gestational day 15. On postnatal day 50, male and female offspring were randomized into one of three conditions that differed in terms of cage size, number of cage mates (social stimulation) and enrichment materials. Spatial discrimination ability and social behavior were assessed six weeks later. Similar to our previously published work in males, our results revealed that a single LPS injection during mid gestation disrupted spatial discrimination ability in female rats. Postpubertal EE rescued this disruption. On the endocrine level, EE dampened elevations in plasma corticosterone that followed MIA, which may mediate EE's rehabilitative effects in female offspring. Within the prefrontal cortex, hippocampus, amygdala, and hypothalamus, MIA and EE altered the mRNA expression of several genes associated with resiliency and synaptic plasticity in both sexes. Overall, our findings provide further evidence that EE may serve as a therapeutic intervention for MIA-induced behavioral and cognitive deficits. Moreover, we identify some sexually dimorphic molecular mechanisms that may underlie these impairments and their rescue.

Prenatal and early life diesel exhaust exposure disrupts cortical lamina organization: Evidence for a reelin-related pathogenic pathway induced by interleukin-6

Several epidemiological studies have shown associations between developmental exposure to traffic-related air pollution and increased risk for autism spectrum disorders (ASD), a spectrum of neurodevelopmental disorders with increasing prevalence rate in the United States. Though animal studies have provided support for these associations, little is known regarding possible underlying mechanisms. In a previous study we found that exposure of C57BL/6J mice of both sexes to environmentally relevant levels (250-300 µg/m³) of diesel exhaust (DE) from embryonic day 0 to postnatal day 21 (E0 to PND21) caused significant changes in all three characteristic behavioral domains of ASD in the offspring. In the present study we investigated a potential mechanistic pathway that may be of relevance for ASD-like changes associated with developmental DE exposure. Using the same DE exposure protocol (250-300 µg/m³ DE from E0 to PND21) several molecular markers were examined in the brains of male and female mice at PND3, 21, and 60. Exposure to DE as above increased levels of interleukin-6 (IL-6) in placenta and in neonatal brain. The JAK2/STAT3 pathway, a target for IL-6, was activated by STAT3 phosphorylation, and the expression of DNA methyltransferase 1 (DNMT1), a STAT3 target gene, was increased in DE-exposed neonatal brain. DNMT1 has been reported to down-regulate expression of reelin (RELN), an extracellular matrix glycoprotein important in regulating the processes of neuronal migration. RELN is considered an important modulator for ASD, since there are several polymorphisms in this gene linked to the disease, and since lower levels of RELN have been reported in brains of ASD patients. We observed decreased RELN expression in brains of the DE-exposed mice at PND3. Since disorganized patches in the prefrontal cortex have been reported in ASD patients and disrupted cortical organization has been found in RELN-deficient mice, we also assessed cortical organization, by labeling cells expressing the lamina-specific-markers RELN and calretinin. In DE-exposed mice we found increased cell density in deeper cortex (lamina layers VI-IV) for cells expressing either RELN or calretinin. These findings demonstrate that developmental DE exposure is associated with subtle disorganization of the cerebral cortex at PND60, and suggest a pathway involving IL-6, STAT3, and DNMT1 leading to downregulation of RELN expression that could be contributing to this long-lasting disruption in cortical laminar organization.

Altered Intestinal Morphology and Microbiota Composition in the Autism Spectrum Disorders Associated SHANK3 Mouse Model

Autism spectrum disorders (ASD) are a group of neurodevelopmental disorders characterized by deficits in social interaction and communication, and repetitive behaviors. In addition, co-morbidities such as gastro-intestinal problems have frequently been reported. Mutations and deletion of proteins of the SH3 and multiple ankyrin repeat domains (SHANK) gene-family were identified in patients with ASD, and Shank knock-out mouse models display autism-like phenotypes. SHANK3 proteins are not only expressed in the central nervous system (CNS). Here, we show expression in gastrointestinal (GI) epithelium and report a significantly different GI morphology in Shank3 knock-out (KO) mice. Further, we detected a significantly altered microbiota composition measured in feces of Shank3 KO mice that may contribute to inflammatory responses affecting brain development. In line with this, we found higher E. coli lipopolysaccharide levels in liver samples of Shank3 KO mice, and detected an increase in Interleukin-6 and activated astrocytes in Shank3 KO mice. We conclude that apart from its well-known role in the CNS, SHANK3 plays a specific role in the GI tract that may contribute to the ASD phenotype by extracerebral mechanisms.

Poly(I:C) alters placental and fetal brain amino acid transport in a rat model of maternal immune activation

PROBLEM

Maternal immune activation (MIA) during pregnancy is associated with increased chances of neurodevelopmental disorders including schizophrenia and autism spectrum disorder (ASD). However, the exact mechanism through which MIA contributes to altered neurodevelopment is unknown. Due to the important role that amino acids play in neurodevelopment, altered amino acid transport could play a role in neurodevelopmental disorders. Indeed, altered plasma concentrations of multiple amino acids have been reported in individuals with ASD or schizophrenia. Therefore, our objective was to determine whether virally mediated MIA induces changes in amino acid transporters in the placenta and fetal brain.

METHOD OF STUDY

Pregnant rats were administered poly(I:C) on gestational day 14, and placental and fetal tissues were collected 6, 24, and 48 hours later. Amino acid transporter expression was measured in the placenta and fetal brain using qPCR, Western blotting, and Simple Western. Free amino acid concentrations in the fetal brain were quantified using HPLC.

RESULTS

Poly(I:C) increased mRNA expression of several amino acid transporters in the placenta and fetal brain over these timepoints. Conversely, poly(I:C) imposed significant decreases in the protein expression of ASCT1 and EAAT2 in placenta and expression of SNAT5, EAAT1, and GLYT1 in fetal brain. Functional consequences of altered transporter expression were demonstrated through widespread changes in the concentrations of free amino acids in the fetal brains.

CONCLUSION

Together, these results represent novel findings with the poly(I:C) MIA model and contribute to the understanding of how MIA during pregnancy potentially leads to neurodevelopmental disorders.

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.

Maternal Inflammation and Neurodevelopmental Programming: A Review of Preclinical Outcomes and Implications for Translational Psychiatry

Early disruptions to neurodevelopment are highly relevant to understanding both psychiatric risk and underlying pathophysiology that can be targeted by new treatments. Much convergent evidence from the human literature associates inflammation during pregnancy with later neuropsychiatric disorders in offspring. Preclinical models of prenatal inflammation have been developed to examine the causal maternal physiological and offspring neural mechanisms underlying these findings. Here we review the strengths and limitations of preclinical models used for these purposes and describe selected studies that have shown maternal immune impacts on the brain and behavior of offspring. Maternal immune activation in mice, rats, nonhuman primates, and other mammalian model species have demonstrated convergent outcomes across methodologies. These outcomes include shifts and/or disruptions in the normal developmental trajectory of molecular and cellular processes in the offspring brain. Prenatal developmental origins are critical to a mechanistic understanding of maternal immune activation-induced alterations to microglia and immune molecules, brain growth and development, synaptic morphology and physiology, and anxiety- and depression-like, sensorimotor, and social behaviors. These phenotypes are relevant to brain functioning across domains and to anxiety and mood disorders, schizophrenia, and autism spectrum disorder, in which they have been identified. By turning a neurodevelopmental lens on this body of work, we emphasize the importance of acute changes to the prenatal offspring brain in fostering a better understanding of potential mechanisms for intervention. Collectively, overlapping results across maternal immune activation studies also highlight the need to examine preclinical offspring neurodevelopment alterations in terms of a multifactorial immune milieu, or immunome, to determine potential mechanisms of psychiatric risk.

Reprint of: Serotonin as a link between the gut-brain-microbiome axis in autism spectrum disorders

Autism-spectrum disorder (ASD) is a neurodevelopmental disorder characterized by persistent deficits in social communication and repetitive patterns of behavior. ASD is, however, often associated with medical comorbidities and gastrointestinal (GI) dysfunction is among the most common. Studies have demonstrated a correlation between GI dysfunction and the degree of social impairment in ASD. The etiology of GI abnormalities in ASD is unclear, though the association between GI dysfunction and ASD-associated behaviors suggest that overlapping developmental defects in the brain and the intestine and/or a defect in communication between the enteric and central nervous systems (ENS and CNS, respectively), known as the gut-brain axis, could be responsible for the observed phenotypes. Brain-gut abnormalities have been increasingly implicated in several disease processes, including ASD. As a critical modulator of ENS and CNS development and function, serotonin may be a nexus for the gut-brain axis in ASD. This paper reviews the role of serotonin in ASD from the perspective of the ENS. A murine model that has been demonstrated to possess brain, behavioral and GI abnormalities mimicking those seen in ASD harbors the most common serotonin transporter (SERT) based mutation (SERT Ala56) found in children with ASD. Discussion of the gut-brain manifestations in the SERT Ala56 mice, and their correction with developmental administration of a 5-HT₄ agonist, are also addressed in conjunction with other future directions for diagnosis and treatment.

The GLP-1 analog, liraglutide prevents the increase of proinflammatory mediators in the hippocampus of male rat pups submitted to maternal perinatal food restriction

Background

Perinatal maternal malnutrition is related to altered growth of tissues and organs. The nervous system development is very sensitive to environmental insults, being the hippocampus a vulnerable structure, in which altered number of neurons and granular cells has been observed. Moreover, glial cells are also affected, and increased expression of proinflammatory mediators has been observed. We studied the effect of Glucagon-like peptide-1 receptor (GLP-1R) agonists, liraglutide, which have very potent metabolic and neuroprotective effects, in order to ameliorate/prevent the glial alterations present in the hippocampus of the pups from mothers with food restriction during pregnancy and lactation (maternal perinatal food restriction—MPFR).

Methods

Pregnant Sprague-Dawley rats were randomly assigned to 50% food restriction (FR; n = 12) or ad libitum controls (CT, n = 12) groups at day of pregnancy 12 (GD12). From GD14 to parturition, pregnant FR and CT rats were treated with liraglutide (100 μg/kg) or vehicle. At postnatal day 21 and before weaning, 48 males and 45 females (CT and MPFR) were sacrificed. mRNA expression levels of interleukin-1β (IL1β), interleukin-6 (IL-6), nuclear factor-κβ, major histocompatibility complex-II (MHCII), interleukin 10 (IL10), arginase 1 (Arg1), and transforming growth factor (TGFβ) were assessed in the hippocampus by quantitative real-time polymerase chain reaction. Iba1 and GFAP-immunoreactivity were assessed by immunocytochemistry.

Results

The mRNA expression IL1β, IL6, NF-κB, and MHCII increased in the hippocampus of male but not in female pups from MPFR. In addition, there was an increase in the percentage of GFAP and Iba1-immupositive cells in the dentate gyrus compared to controls, indicating an inflammatory response in the brain. On the other hand, liraglutide treatment prevented the neuroinflammatory process, promoting the production of anti-inflammatory molecules such as IL10, TGFβ, and arginase 1, and decreasing the number and reactivity of microglial cells and astrocytes in the hippocampus of male pups.

Conclusion

Therefore, the GLP-1 analog, liraglutide, emerges as neuroprotective drug that minimizes the harmful effects of maternal food restriction, decreasing neuroinflammation in the hippocampus in a very early stage.

Maternal immune activation, central nervous system development and behavioral phenotypes

Maternal immune activation (MIA) refers to a maternal immune system triggered by infectious or infectious-like stimuli. A cascade of cytokines and immunologic alterations are transmitted to the fetus, resulting in adverse phenotypes most notably in the central nervous system. Epidemiologic studies implicate maternal infections in a variety of neuropsychiatric disorders, most commonly autism spectrum disorders and schizophrenia. In animal models, MIA causes neurochemical and anatomic changes in the brain that correspond to those found in humans with the disorders. As our understanding of the interactions between environment, genetics, and immune system grows, the role of alternative, noninfectious risk factors, such as prenatal stress, obesity, and the gut microbiome also becomes clearer. This review considers how infectious and noninfectious etiologies activate the maternal immune system. Their impact on fetal programming and neuropsychiatric disorders in offspring is examined in the context of human and animal studies.

Prevalence of Autism Spectrum Disorder in a large Italian catchment area: a school-based population study within the ASDEU project

AIMS

This study aims to estimate Autism Spectrum Disorders (ASD) prevalence in school-aged children in the province of Pisa (Italy) using the strategy of the ASD in the European Union (ASDEU) project.

METHODS

A multistage approach was used to identify cases in a community sample (N = 10 138) of 7-9-year-old children attending elementary schools in Pisa - Italy. First, the number of children with a disability certificate was collected from the Local Health Authority and an ASD diagnosis was verified by the ASDEU team. Second, a Teacher Nomination form (TN) to identify children at risk for ASD was filled in by teachers who joined the study and the Social Communication Questionnaire (SCQ) was filled in by the parents of children identified as positive by the TN; a comprehensive assessment, which included the Autism Diagnostic Observation Schedule-Second Edition, was performed for children with positive TN and SCQ⩾9.

RESULTS

A total of 81 children who had a disability certificate also had ASD (prevalence: 0.79%, i.e. 1/126). Specifically, 66 children (57 males and nine females; 62% with intellectual disability -ID-) were certified with ASD, whereas another 15 (11 males and four females; 80% with ID) were recognised as having ASD among those certified with another neurodevelopmental disorder. Considering the population of 4417 (children belonging to schools which agreed to participate in the TN/SCQ procedure) and using only the number of children certified with ASD, the prevalence (38 in 4417) was 0.86%, i.e. one in 116. As far as this population is concerned, the prevalence rises to 1% if we consider the eight new cases (six males and two females; no subject had ID) identified among children with no pre-existing diagnoses and to 1.15%, i.e., one in 87, if probabilistic estimation is used.

CONCLUSIONS

This is the first population-based ASD prevalence study conducted in Italy so far and its results indicate a prevalence of ASD in children aged 7-9 years of about one in 87. This finding may help regional, national and international health planners to improve ASD policies for ASD children and their families in the public healthcare system.

Comprehensive literature data-mining analysis reveals a broad genetic network functionally associated with autism spectrum disorder

Previous studies have indicated that genetic factors are the predominate cause of Autism spectrum disorder (ASD). Nevertheless, to the best of our knowledge, to date no systematic study has summarized these data and provided an objective, complete list of genes with demonstrated associations with ASD. The present study included a literature data mining analysis of >2,064 articles including publications from January 2000 to April 2016, which identified 488 ASD target genes. Gene set enrichment analysis (GSEA), sub-network enrichment analysis (SNEA) and network connectivity analysis (NCA) were conducted to assess the functional profile and pathogenic significance of these genes. A total of 2 literature metrics were proposed to prioritize the curated ASD genes with specific significance. This approach resulted in the development of an ASD genetic database. Subsequent analysis indicated that 391 of the 488 genes were enriched in 97 biological pathways (P<1×10⁻⁸), demonstrating significant functional associations with each other. The majority of these curated ASD genes also serve significant roles in the pathogenesis of other neuropsychiatric disorders. These results suggest that the genetic causes of ASD are within a large network composed of functionally-associated genes. The genetic database, together with the metric scores developed in the present study, provides a basis for future biological/genetic modeling in the field.

Social impairments in autism spectrum disorder are related to maternal immune history profile

Maternal immune activation has been highlighted as a factor that might increase the risk and severity of autism spectrum disorder (ASD) in children. Preclinical animal evidence shows that immune activation in mothers during pregnancy causes ASD-like behavioural traits in offspring. To this point, there has been no investigation of whether immune system activation in human mothers during pregnancy is associated with more severe symptoms in children with ASD. In this study, data from an existing ASD cohort (N=220) were analysed to investigate whether immune conditions in the mother were associated with greater severity of autism-related symptoms. Results showed that children whose mothers reported a history of immune activation (allergies and asthma) had significantly higher scores on the Social Responsiveness Scale (SRS; P=0.016), suggesting more severe social impairment symptoms in these children. This increasing severity of social impairment symptoms was further shown on the SRS cognition (P=0.007) and mannerisms (P=0.002) subscales. While immune history was associated with an increase in the severity of social impairment symptoms, history of autoimmune conditions in the mother did not have any effect in this cohort. To the best of our knowledge, this study is the first to show an association between immune activation history in the mother and increased ASD symptom severity in children with ASD. These findings support the idea of an immune system-mediated subtype in ASD, where the immune history of the mother may be an important factor.

Symptom severity in autism spectrum disorder is related to the frequency and severity of nausea and vomiting during pregnancy: a retrospective case-control study

Background

Nausea and vomiting during pregnancy (NVP) is thought to be caused by changes in maternal hormones during pregnancy. Differences in hormone exposure during prenatal life have been implicated in the causal pathways for some cases of autism spectrum disorder (ASD). However, no study has investigated whether the presence and severity of NVP may be related to symptom severity in offspring with ASD.

Methods

A large sample of children with ASD (227 males and 60 females, aged 2 to 18 years) received a clinical assessment, during which parents completed questionnaires regarding their child’s social (Social Responsiveness Scale, SRS) and communication (Children’s Communication Checklist–2nd edition, CCC-2) symptoms. Parents also reported on a 5-point scale the frequency and severity of NVPs during the pregnancy of the child being assessed: (1) no NVP during the pregnancy, (2) occasional nausea, but no vomiting, (3) daily nausea, but no vomiting, (4) occasional vomiting, with or without nausea, and (5) daily nausea and vomiting.

Results

Impairments in social responsiveness in offspring, as indexed by SRS total score, significantly increased as a function of the frequency and severity of their mothers’ NVP, as did the level of language difficulties as indexed by the Global Communication Composite of the CCC-2.

Conclusions

The strong, positive association between increasing frequency and severity of NVP and ASD severity in offspring provides further evidence that exposure to an atypical hormonal environment during prenatal life may affect neurodevelopment and contribute to the ASD phenotype. Given that the measure of NVP symptoms in the current study was based on retrospective recall, replication of this finding is required before strong conclusions can be drawn.

Electronic supplementary material

The online version of this article (10.1186/s13229-018-0223-7) contains supplementary material, which is available to authorized users.

The placental immune response is dysregulated developmentally vitamin D deficient rats: Relevance to autism

Emerging evidence suggests that maternal or developmental vitamin D (DVD) deficiency is a risk factor for Autism Spectrum Disorders. A well-established association has also been found between gestational infection and increased incidence of autism. Placenta mediates the maternal immune response in respect to the foetus. The placenta is also a major source of vitamin D and locally produced vitamin D is an essential regulator of immune function during pregnancy. Here we investigate the effects of DVD-deficiency on baseline placental immune status and in response to the well-known viral and bacterial immune activating agents polyriboinosinic-polyribocytidylic acid (poly(I:C) and lipopolysaccharide (LPS). We show DVD-deficiency does not affect baseline inflammatory cytokines in placenta. However, when challenged with poly(I:C) but not LPS, DVD-deficient placentas from male foetuses had higher production of IL-6 and 1L-1β compared to control placentas. This suggests the developing DVD-deficient male foetus may be particularly vulnerable to maternal viral exposures. This in turn may have adverse implications for the developing male brain. In conclusion, a dysregulated placental immune response may provide a plausible mechanism for both the epidemiological links between DVD-deficiency and increased male incidence of developmental conditions such as autism.