Neuroinflammation in preterm babies and autism spectrum disorders

Antioxidant-Effective Quercetin Through Modulation of Brain Interleukin-13 Mitigates Autistic-Like Behaviors in the Propionic Acid-Induced Autism Model in Rats

Overproduction of reactive oxygen species occurs when inflammation induces oxidative stress in macrophages and microglia, leading to a self-sustaining cycle of cellular damage and neuroinflammation. Oxidative stress and neuroinflammation are well-established contributors to the pathophysiology of autism spectrum disorders, which are associated with impaired neuronal function, neuronal loss, and behavioral deficits. Damaged cells, through microglial activation, release additional inflammatory mediators under conditions of oxidative stress, exacerbating neuronal damage. Quercetin, a powerful dietary antioxidant, has been shown to scavenge free radicals, reduce oxidative stress, and inhibit inflammatory pathways. Given these properties, we hypothesize that quercetin may improve learning and social skills in individuals with autism spectrum disorders by alleviating oxidative stress and reducing brain levels of inflammatory cytokines. In this study, an autism model was established in 30 rats by intraperitoneal injection of 250 mg/kg/day propionic acid (PPA) for five days. The study groups were as follows: Group 1: Normal ontrol (n = 10); Group 2: PPA + saline (PPAS, n = 10); Group 3: PPA + Quercetin (PPAQ, n = 10). All treatments were administered for 15 days. At the end of the treatment, histological and biochemical analyses of brain tissue and behavioral tests related to autistic-like behaviors were performed. Malondialdehyde, tumor necrosis factor-alpha, and interleukin-13 levels in brain homogenates were significantly higher in the PPAS group compared to the control group, indicating elevated oxidative stress and inflammation following PPA exposure. The PPAQ group significantly reduced oxidative stress parameters and inflammatory biomarkers, demonstrating its antioxidant and anti-inflammatory effects. This biochemical improvement was accompanied by preserving Purkinje cells and neuronal populations, significantly reduced in the PPAS group. Moreover, quercetin-treated rats exhibited improved social behavior and learning, which were severely impaired in the PPAS group. These findings, when interpreted together, suggest that quercetin exerts its neuroprotective effects by targeting oxidative stress and neuroinflammation, thereby preventing neuronal cell loss and alleviating behavioral deficits associated with autism spectrum disorders.

Systemic Rejuvenating Interventions: Perspectives on Neuroinflammation and Blood-Brain Barrier Integrity

The aging process results in structural, functional, and immunological changes in the brain, which contribute to cognitive decline and increase vulnerability to neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), and stroke-related complications. Aging leads to cognitive changes and also affect executive functions. Additionally, it causes neurogenic and neurochemical alterations, such as a decline in dopamine and acetylcholine levels, which also impact cognitive performance. The chronic inflammation caused by aging contributes to the impairment of the blood-brain barrier (BBB), contributing to the infiltration of immune cells and exacerbating neuronal damage. Therefore, rejuvenating therapies such as heterochronic parabiosis, cerebrospinal fluid (CSF) administration, plasma, platelet-rich plasma (PRP), and stem cell therapy have shown potential to reverse these changes, offering new perspectives in the treatment of age-related neurological diseases. This review focuses on highlighting the effects of rejuvenating interventions on neuroinflammation and the BBB.

Prenatal inflammation exacerbates hyperoxia-induced neonatal brain injury

BACKGROUND

Premature born infants are at high risk to develop white matter injury (WMI). Hyperoxia and perinatal inflammation are main risk factors for preterm birth and associated brain injury. To date the majority of experimental studies have focused on isolated insults. However, clinically, WMI injury is a multifactorial disorder caused by a variety of triggers. To establish a clinically relevant rodent model of WMI, we combined prenatal inflammation with postnatal hyperoxia to investigate individual, and additive or synergistic effects on inflammatory processes, myelination and grey matter development.

METHODS

At embryonic day 20, pregnant Wistar rat dams received either a single intraperitoneal injection of 100 µg/ kg lipopolysaccharide (LPS) or sodium chloride. Offspring were either exposed to hyperoxia (80% O2) or normoxia (21% O2) from postnatal day 3 to 5. Animals were sacrificed immediately after hyperoxia or 6 days later, corresponding to term-equivalent age. White and grey matter development and neuroinflammatory responses were investigated at cellular and molecular levels applying immunohistochemistry, western blotting, real time PCR in brain tissues and multiplex protein expression analysis on serum samples.

RESULTS

Prenatal inflammation combined with postnatal hyperoxia resulted in reduced body weight and length in the offspring, accompanied by increased serum leptin levels at term equivalent age. The altered body parameters, like body weight, were associated with decreased brain volume, thinning of deep cortical layers and hypomyelination. As potential underlying mechanisms, we identified severe myelination deficits and an increased microglia activation associated with elevated inflammatory cytokine expression in brain tissues, while peripheral cytokine levels were reduced. Interestingly, effects on body size were mainly mediated by prenatal LPS, independent of hyperoxia, while oligodendrocyte degeneration was mainly induced by postnatal hyperoxia, independent of prenatal inflammation. However, for the majority of pathological changes, including brain size, myelination deficits, microglia activation and inflammatory cytokine expression, additive or synergistic effects were detected.

CONCLUSION

Prenatal inflammation combined with postnatal hyperoxia results in aggravated myelination deficits and inflammatory responses compared to single insults, making it an ideal model to improve our understanding of the complex pathophysiology underlying WMI and to evaluate urgently needed therapies.

C-section and systemic inflammation synergize to disrupt the neonatal gut microbiota and brain development in a model of prematurity

Infants born very preterm (below 28 weeks of gestation) are at high risk of developing neurodevelopmental disorders, such as intellectual deficiency, autism spectrum disorders, and attention deficit. Preterm birth often occurs in the context of perinatal systemic inflammation due to chorioamnionitis and postnatal sepsis. In addition, C-section is often performed for very preterm neonates to avoid hypoxia during a vaginal delivery. We have developed and characterized a mouse model based on intraperitoneal injections of IL-1β between postnatal days one and five to reproduce perinatal systemic inflammation. This model replicates several neuropathological, brain imaging, and behavioral deficits observed in preterm infants. We hypothesized that C-sections could synergize with systemic inflammation to induce more severe brain abnormalities. We observed that C-sections significantly exacerbated the deleterious effects of IL-1β on reduced gut microbial diversity, increased levels of circulating peptidoglycans, abnormal microglia/macrophage reactivity, impaired myelination, and reduced functional connectivity in the brain relative to vaginal delivery plus intraperitoneal saline. These data demonstrate the deleterious synergistic effects of C-section and neonatal systemic inflammation on brain maldevelopment and malfunction, two conditions frequently observed in very preterm infants, who are at high risk of developing neurodevelopmental disorders.

Engrailed-2 and inflammation convergently and independently impinge on cerebellar Purkinje cell differentiation

Autism spectrum disorders (ASD) have a complex pathogenesis thought to include both genetic and extrinsic factors. Among the latter, inflammation of the developing brain has recently gained growing attention. However, how genetic predisposition and inflammation might converge to precipitate autistic behavior remains elusive. Cerebellar structure and function are well known to be affected in autism. We therefore used cerebellar slice cultures to probe whether inflammatory stimulation and (over)expression of the autism susceptibility gene Engrailed-2 interact in shaping differentiation of Purkinje cells, key organizers of cerebellar histogenesis and function. We show that lipopolysaccharide treatment reduces Purkinje cell dendritogenesis and that this effect is enhanced by over-expression of Engrailed-2 in these cells. The effects of lipopolysaccharide can be blocked by inhibiting microglia proliferation and also by blocking tumor necrosis factor alpha receptor signaling, suggesting microglia and tumor necrosis factor alpha are major players in this scenario. These findings identify Purkinje cells as a potential integrator of genetic and environmental signals that lead to an autism-associated morphology.

Prenatal environmental risk factors for autism spectrum disorder and their potential mechanisms

Autism spectrum disorder (ASD) is a neurodevelopmental disorder that is globally increasing in prevalence. The rise of ASD can be partially attributed to diagnostic expansion and advocacy efforts; however, the interplay between genetic predisposition and modern environmental exposures is likely driving a true increase in incidence. A range of evidence indicates that prenatal exposures are critical. Infection during pregnancy, gestational diabetes, and maternal obesity are established risk factors for ASD. Emerging areas of research include the effects of maternal use of selective serotonin reuptake inhibitors, antibiotics, and exposure to toxicants during pregnancy on brain development and subsequent ASD. The underlying pathways of these risk factors remain uncertain, with varying levels of evidence implicating immune dysregulation, mitochondrial dysfunction, oxidative stress, gut microbiome alterations, and hormonal disruptions. This narrative review assesses the evidence of contributing prenatal environmental factors for ASD and associated mechanisms as potential targets for novel prevention strategies.

Caffeine: The Story beyond Oxygen-Induced Lung and Brain Injury in Neonatal Animal Models-A Narrative Review

Caffeine is one of the most commonly used drugs in intensive care to stimulate the respiratory control mechanisms of very preterm infants. Respiratory instability, due to the degree of immaturity at birth, results in apnea of prematurity (AOP), hyperoxic, hypoxic, and intermittent hypoxic episodes. Oxidative stress cannot be avoided as a direct reaction and leads to neurological developmental deficits and even a higher prevalence of respiratory diseases in the further development of premature infants. Due to the proven antioxidant effect of caffeine in early use, largely protective effects on clinical outcomes can be observed. This is also impressively observed in experimental studies of caffeine application in oxidative stress-adapted rodent models of damage to the developing brain and lungs. However, caffeine shows undesirable effects outside these oxygen toxicity injury models. This review shows the effects of caffeine in hyperoxic, hypoxic/hypoxic-ischemic, and intermittent hypoxic rodent injury models, but also the negative effects on the rodent organism when caffeine is administered without exogenous oxidative stress. The narrative analysis of caffeine benefits in cerebral and pulmonary preterm infant models supports protective caffeine use but should be given critical consideration when considering caffeine treatment beyond the recommended corrected gestational age.

Role of the Gut Microbiota-Brain Axis in Brain Damage in Preterm Infants

The greatest repository of microbes in the human body, the intestinal microbiome, is involved in neurological development, aging, and brain illnesses such as white matter injury (WMI) in preterm newborns. Intestinal microorganisms constitute a microbial gut-brain axis that serves as a crucial conduit for communication between the gut and the nervous system. This axis controls inflammatory cytokines, which in turn influence the differentiation of premyelinating oligodendrocytes (pre-OLs) and influence the incidence of WMI in premature newborns through the metabolites generated by gut microbes. Here, we describe the effects of white matter injury (WMI) on intestinal dysbiosis and gut dysfunction and explain the most recent research findings on the gut-brain axis in both humans and animals. We also emphasize the delicate relationship that exists between the microbiota and the brain following acute brain injury. The role that the intestinal microflora plays in influencing host metabolism, the immune system, brain health, and the course of disease is becoming increasingly clear, but there are still gaps in the field of WMI treatment. Thus, this review demonstrates the function of the gut microflora-brain axis in WMI and elucidates the possible mechanisms underlying the communication between gut bacteria and the developing brain via the gut-brain axis, potentially opening up new avenues for microbial-based intervention and treatment for preterm WMI.

Central Causation of Autism/ASDs via Excessive [Ca2+]i Impacting Six Mechanisms Controlling Synaptogenesis during the Perinatal Period: The Role of Electromagnetic Fields and Chemicals and the NO/ONOO(-) Cycle, as Well as Specific Mutations

The roles of perinatal development, intracellular calcium [Ca2+]i, and synaptogenesis disruption are not novel in the autism/ASD literature. The focus on six mechanisms controlling synaptogenesis, each regulated by [Ca2+]i, and each aberrant in ASDs is novel. The model presented here predicts that autism epidemic causation involves central roles of both electromagnetic fields (EMFs) and chemicals. EMFs act via voltage-gated calcium channel (VGCC) activation and [Ca2+]i elevation. A total of 15 autism-implicated chemical classes each act to produce [Ca2+]i elevation, 12 acting via NMDA receptor activation, and three acting via other mechanisms. The chronic nature of ASDs is explained via NO/ONOO(-) vicious cycle elevation and MeCP2 epigenetic dysfunction. Genetic causation often also involves [Ca2+]i elevation or other impacts on synaptogenesis. The literature examining each of these steps is systematically examined and found to be consistent with predictions. Approaches that may be sed for ASD prevention or treatment are discussed in connection with this special issue: The current situation and prospects for children with ASDs. Such approaches include EMF, chemical avoidance, and using nutrients and other agents to raise the levels of Nrf2. An enriched environment, vitamin D, magnesium, and omega-3s in fish oil may also be helpful.

Impact of Maternal Environment and Inflammation on Fetal Neurodevelopment

During intrauterine life, external stimuli including maternal nutrition, lifestyle, socioeconomic conditions, anxiety, stress, and air pollution can significantly impact fetal development. The human brain structures begin to form in the early weeks of gestation and continue to grow and mature throughout pregnancy. This review aims to assess, based on the latest research, the impact of environmental factors on fetal and neonatal brain development, showing that oxidative stress and inflammation are implied as a common factor for most of the stressors. Environmental insults can induce a maternal inflammatory state and modify nutrient supply to the fetus, possibly through epigenetic mechanisms, leading to significant consequences for brain morphogenesis and neurological outcomes. These risk factors are often synergic and mutually reinforcing. Fetal growth restriction and preterm birth represent paradigms of intrauterine reduced nutrient supply and inflammation, respectively. These mechanisms can lead to an increase in free radicals and, consequently, oxidative stress, with well-known adverse effects on the offspring's neurodevelopment. Therefore, a healthy intrauterine environment is a critical factor in supporting normal fetal brain development. Hence, healthcare professionals and clinicians should implement effective interventions to prevent and reduce modifiable risk factors associated with an increased inflammatory state and decreased nutrient supply during pregnancy.

The research landscape concerning environmental factors in neurodevelopmental disorders: Endocrine disrupters and pesticides-A review

In recent years, environmental epidemiology and toxicology have seen a growing interest in the environmental factors that contribute to the increased prevalence of neurodevelopmental disorders, with the purpose of establishing appropriate prevention strategies. A literature review was performed, and 192 articles covering the topic of endocrine disruptors and neurodevelopmental disorders were found, focusing on polychlorinated biphenyls, polybrominated diphenyl ethers, bisphenol A, and pesticides. This study contributes to analyzing their effect on the molecular mechanism in maternal and infant thyroid function, essential for infant neurodevelopment, and whose alteration has been associated with various neurodevelopmental disorders. The results provide scientific evidence of the association that exists between the environmental neurotoxins and various neurodevelopmental disorders. In addition, other possible molecular mechanisms by which pesticides and endocrine disruptors may be associated with neurodevelopmental disorders are being discussed.

Autism spectrum disorder: pathogenesis, biomarker, and intervention therapy

Autism spectrum disorder (ASD) has become a common neurodevelopmental disorder. The heterogeneity of ASD poses great challenges for its research and clinical translation. On the basis of reviewing the heterogeneity of ASD, this review systematically summarized the current status and progress of pathogenesis, diagnostic markers, and interventions for ASD. We provided an overview of the ASD molecular mechanisms identified by multi-omics studies and convergent mechanism in different genetic backgrounds. The comorbidities, mechanisms associated with important physiological and metabolic abnormalities (i.e., inflammation, immunity, oxidative stress, and mitochondrial dysfunction), and gut microbial disorder in ASD were reviewed. The non-targeted omics and targeting studies of diagnostic markers for ASD were also reviewed. Moreover, we summarized the progress and methods of behavioral and educational interventions, intervention methods related to technological devices, and research on medical interventions and potential drug targets. This review highlighted the application of high-throughput omics methods in ASD research and emphasized the importance of seeking homogeneity from heterogeneity and exploring the convergence of disease mechanisms, biomarkers, and intervention approaches, and proposes that taking into account individuality and commonality may be the key to achieve accurate diagnosis and treatment of ASD.

Chorioamnionitis accelerates granule cell and oligodendrocyte maturation in the cerebellum of preterm nonhuman primates

BACKGROUND

Preterm birth is often associated with chorioamnionitis and leads to increased risk of neurodevelopmental disorders, such as autism. Preterm birth can lead to cerebellar underdevelopment, but the mechanisms of disrupted cerebellar development in preterm infants are not well understood. The cerebellum is consistently affected in people with autism spectrum disorders, showing reduction of Purkinje cells, decreased cerebellar grey matter, and altered connectivity.

METHODS

Preterm rhesus macaque fetuses were exposed to intra-amniotic LPS (1 mg, E. coli O55:B5) at 127 days (80%) gestation and delivered by c-section 5 days after injections. Maternal and fetal plasma were sampled for cytokine measurements. Chorio-decidua was analyzed for immune cell populations by flow cytometry. Fetal cerebellum was sampled for histology and molecular analysis by single-nuclei RNA-sequencing (snRNA-seq) on a 10× chromium platform. snRNA-seq data were analyzed for differences in cell populations, cell-type specific gene expression, and inferred cellular communications.

RESULTS

We leveraged snRNA-seq of the cerebellum in a clinically relevant rhesus macaque model of chorioamnionitis and preterm birth, to show that chorioamnionitis leads to Purkinje cell loss and disrupted maturation of granule cells and oligodendrocytes in the fetal cerebellum at late gestation. Purkinje cell loss is accompanied by decreased sonic hedgehog signaling from Purkinje cells to granule cells, which show an accelerated maturation, and to oligodendrocytes, which show accelerated maturation from pre-oligodendrocytes into myelinating oligodendrocytes.

CONCLUSION

These findings suggest a role of chorioamnionitis on disrupted cerebellar maturation associated with preterm birth and on the pathogenesis of neurodevelopmental disorders among preterm infants.

Exploring the effects of embryonic and neonatal exposure to lipopolysaccharides on oligodendrocyte differentiation in the rat hippocampus and the protective effect of alpha-glycosyl isoquercitrin

This study compared the effects of embryonic and neonatal lipopolysaccharides (LPS) exposure (E-LPS and N-LPS) on oligodendrocyte (OL) differentiation in the hippocampus of male rats and explored the protective effect of the antioxidant alpha-glycosyl isoquercitrin (AGIQ). Using SD rats, LPS exposure occurred either intraperitoneally in dams between gestational days 15 and 16 (50 µg/kg body weight/time) or in male pups on postnatal day (PND) 3 (1 mg/kg body weight). Under both regimens, AGIQ at 0.5% (w/w) was supplemented, to dams from the gestation period (before LPS exposure) until weaning on PND 21 and to male offspring from weaning until PND 77 (adulthood). Compared with a control treatment, E-LPS treatment resulted in fewer NG2+ OL progenitor cells (OPCs) and an upregulation of Tcf4 at PND 6; by PND 21, low NG2+ OPC number persisted, but OLIG2+ OL lineage cells increased, while CNPase+ mature OLs counts were unchanged. By contrast, N-LPS treatment resulted in fewer OLIG2+ cells and an upregulation of Bmp4 at PND 6; by PND 21, NG2+ OPCs decreased, while GFAP+ astrocytes increased at both PND 6 and 21. After N-LPS treatment, Kl and Yy1 were downregulated and there were fewer Klotho+ and CNPase+ cells at PND 21. Results suggest that E-LPS treatment facilitates OPC differentiation into pre- and immature OLs until weaning, while N-LPS treatment suppresses OPC differentiation into mature OLs but facilitates astrocyte generation; however, these changes spontaneously recovered by adulthood under both regimens. AGIQ treatment ameliorated the effects of LPS treatment of both regimens, suggesting that LPS-induced disruption of OPC/OL differentiation occurs via neuroinflammation.

Neurodevelopmental, Mental Health, and Parenting Issues in Preterm Infants

The World Health Organization in its recommendations for the care of preterm infants has drawn attention to the need to address issues related to family involvement and support, including education, counseling, discharge preparation, and peer support. A failure to address these issues may translate into poor outcomes that extend across the lifespan. In this paper, we review the often far-reaching impact of preterm birth on the health and wellbeing of the parents and highlight the ways in which psychological stress may have a negative long-term impact on the parent-child interaction, attachment, and the styles of parenting. This paper addresses the following topics: (1) neurodevelopmental outcomes in preterm infants, including cognitive, sensory, and motor difficulties, (2) long-term mental health issues in premature infants that include elevated rates of anxiety and depressive disorders, autism, and somatization, which may affect social relationships and quality of life, (3) adverse mental health outcomes for parents that include elevated rates of depression, anxiety, and symptoms of post-traumatic stress, as well as increased rates of substance abuse, and relationship strain, (4) negative impacts on the parent-infant relationship, potentially mediated by maternal sensitivity, parent child-interactions, and attachment, and (5) impact on the parenting behaviors, including patterns of overprotective parenting, and development of Vulnerable Child Syndrome. Greater awareness of these issues has led to the development of programs in neonatal mental health and developmental care with some data suggesting benefits in terms of shorter lengths of stay and decreased health care costs.

Preterm Birth by Cesarean Section: The Gut-Brain Axis, a Key Regulator of Brain Development

Understanding the long-term functional implications of gut microbial communities during the perinatal period is a bourgeoning area of research. Numerous studies have revealed the existence of a "gut-brain axis" and the impact of an alteration of gut microbiota composition in brain diseases. Recent research has highlighted how gut microbiota could affect brain development and behavior. Many factors in early life such as the mode of delivery or preterm birth could lead to disturbance in the assembly and maturation of gut microbiota. Notably, global rates of cesarean sections (C-sections) have increased in recent decades and remain important when considering premature delivery. Both preterm birth and C-sections are associated with an increased risk of neurodevelopmental disorders such as autism spectrum disorders, with neuroinflammation a major risk factor. In this review, we explore links between preterm birth by C-sections, gut microbiota alteration, and neuroinflammation. We also highlight C-sections as a risk factor for developmental disorders due to alterations in the microbiome.

A Spectrum of Solutions: Unveiling Non-Pharmacological Approaches to Manage Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a developmental disorder that causes difficulty while socializing and communicating and the performance of stereotyped behavior. ASD is thought to have a variety of causes when accompanied by genetic disorders and environmental variables together, resulting in abnormalities in the brain. A steep rise in ASD has been seen regardless of the numerous behavioral and pharmaceutical therapeutic techniques. Therefore, using complementary and alternative therapies to treat autism could be very significant. Thus, this review is completely focused on non-pharmacological therapeutic interventions which include different diets, supplements, antioxidants, hormones, vitamins and minerals to manage ASD. Additionally, we also focus on complementary and alternative medicine (CAM) therapies, herbal remedies, camel milk and cannabiodiol. Additionally, we concentrate on how palatable phytonutrients provide a fresh glimmer of hope in this situation. Moreover, in addition to phytochemicals/nutraceuticals, it also focuses on various microbiomes, i.e., gut, oral, and vaginal. Therefore, the current comprehensive review opens a new avenue for managing autistic patients through non-pharmacological intervention.

Comorbidities Affecting Children with Autism Spectrum Disorder: A Retrospective Chart Review

Autism spectrum disorder (ASD) is a developmental disorder characterized by deficits in social interaction/communication, restricted interests, and repetitive behaviors. Recent discussions have emerged worldwide regarding the heterogeneity around presentation/etiology and comorbidities. This study aimed to determine the frequency and characteristics of comorbidities among children diagnosed with ASD in Manitoba and to evaluate differences in presentation between those with and without medical comorbidities. We conducted a retrospective chart review of >1900 electronic charts at the only publicly funded referral site for children ≤6 years requiring evaluation for ASD in Manitoba. All children aged 0-6 years diagnosed with ASD at this site between May 2016 and September 2021 were identified. χ2 and t-tests were used to compare groups. Of the total of 1858 children identified, 1452 (78.1%) were boys, 251 (13.5%) were prematurely born, and 539 (29.0%) had ≥1 medical comorbidity. Global developmental delay (GDD) was diagnosed in 428 (23.0%). The age of referral and diagnosis did not differ between groups. Comorbidities were more common among premature children (16.0% vs. 12.5%, p: 0.005) and children with comorbid GDD (34.9% vs. 18.2%, p < 0.001). Neurological comorbidities were most common (37.1%). No sex difference in the overall presence of comorbidities was found (boys = 77.1% vs. 78.5%, p: 0.518); however, girls had a higher incidence of neurological comorbidities, e.g., cerebral palsy, seizures, hypotonia (14.8% vs. 9.64%, p: 0.009), as well as genetic comorbidities (4.92% vs. 2.75%, p: 0.04). The high rates of associated neurological conditions, GDD, and prematurity add heterogeneity to this group leading to potential difficulties with prognosis and service allocation. Primary vs. secondary ASD can be a way of separating individuals based on relevant medical comorbidities.

Early biomarkers of neurodevelopmental disorders in preterm infants: protocol for a longitudinal cohort study

INTRODUCTION

Preterm (PT) infants are at high likelihood for poor neurodevelopmental outcomes, including autism spectrum disorder (ASD), attention-deficit hyperactivity disorder (ADHD) and other neurodevelopmental disorders (NDDs), which could considerably impair the individuals' functions throughout their whole life. The current cohort study aims to investigate adverse outcomes, especially NDDs, in PT children, and the related early aberrant brain developmental biomarkers.

METHODS AND ANALYSIS

This is a prospective cohort study in Beijing, China. We plan to recruit 400 PT infants born at <37 weeks of gestational age (GA), and 200 full-term (FT) controls during the neonatal period (40 weeks corrected GA), then follow them up until they reach 6 years of age. This cohort is designed to assess neuropsychological functions, brain development, related environmental risk factors and the incidence of NDDs by using the following measures: (1) social, emotional, cognitive and sensorimotor functions; (2) MRI, electroencephalogram and functional near-infrared spectroscopy; (3) social economic status, maternal mental health and DNA methylation; and (4) symptoms and diagnosis of NDDs. Main data analyses will include comparing the neurodevelopment outcomes and brain developmental trajectories between PT and FT children using linear or logistic regressions and mixed-effects models. Regression analyses and machine learning will be used to identify early biological predictors and environmental risk or protective factors for later NDDs outcomes.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the research ethics committee of Peking University Third Hospital (M2021087). This study is under review in the Chinese Clinical Trial Register. The study results from the current cohort will be disseminated and popularised through social media to participating parents, as well as parents who are giving care to PT children.

The Central Noradrenergic System in Neurodevelopmental Disorders: Merging Experimental and Clinical Evidence

The aim of this article is to highlight the potential role of the locus-coeruleus-noradrenergic (LC-NA) system in neurodevelopmental disorders (NdDs). The LC is the main brain noradrenergic nucleus, key in the regulation of arousal, attention, and stress response, and its early maturation and sensitivity to perinatal damage make it an interesting target for translational research. Clinical data shows the involvement of the LC-NA system in several NdDs, suggesting a pathogenetic role in the development of such disorders. In this context, a new neuroimaging tool, LC Magnetic Resonance Imaging (MRI), has been developed to visualize the LC in vivo and assess its integrity, which could be a valuable tool for exploring morphological alterations in NdD in vivo in humans. New animal models may be used to test the contribution of the LC-NA system to the pathogenic pathways of NdD and to evaluate the efficacy of NA-targeting drugs. In this narrative review, we provide an overview of how the LC-NA system may represent a common pathophysiological and pathogenic mechanism in NdD and a reliable target for symptomatic and disease-modifying drugs. Further research is needed to fully understand the interplay between the LC-NA system and NdD.

Deciduous tooth biomarkers reveal atypical fetal inflammatory regulation in autism spectrum disorder

Atypical regulation of inflammation has been proposed in the etiology of autism spectrum disorder (ASD); however, measuring the temporal profile of fetal inflammation associated with future ASD diagnosis has not been possible. Here, we present a method to generate approximately daily profiles of prenatal and early childhood inflammation as measured by developmentally archived C-reactive protein (CRP) in incremental layers of deciduous tooth dentin. In our discovery population, a group of Swedish twins, we found heightened inflammation in the third trimester in children with future ASD diagnosis relative to controls (n = 66; 14 ASD cases; critical window: -90 to -50 days before birth). In our replication study, in the US, we observed a similar increase in CRP in ASD cases during the third trimester (n = 47; 23 ASD cases; -128 to -21 days before birth). Our results indicate that the third trimester is a critical period of atypical fetal inflammatory regulation in ASD.

Pathogenesis from the microbial-gut-brain axis in white matter injury in preterm infants: A review

White matter injury (WMI) in premature infants is a unique form of brain injury and a common cause of chronic nervous system conditions such as cerebral palsy and neurobehavioral disorders. Very preterm infants who survive are at high risk of WMI. With developing research regarding the pathogenesis of premature WMI, the role of gut microbiota has attracted increasing attention in this field. As premature infants are a special group, early microbial colonization of the microbiome can affect brain development, and microbiome optimization can improve outcomes regarding nervous system development. As an important communication medium between the gut and the nervous system, intestinal microbes form a microbial-gut-brain axis. This axis affects the occurrence of WMI in premature infants via the metabolites produced by intestinal microorganisms, while also regulating cytokines and mediating oxidative stress. At the same time, deficiencies in the microbiota and their metabolites may exacerbate WMI in premature infants. This confers promise for probiotics and prebiotics as treatments for improving neurodevelopmental outcomes. Therefore, this review attempted to elucidate the potential mechanisms behind the communication of gut bacteria and the immature brain through the gut-brain axis, so as to provide a reference for further prevention and treatment of premature WMI.

Neuroinflammation and Oxidative Stress in the Pathogenesis of Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a neurodevelopmental disorder (NDD) characterized by impairments in social communication, repetitive behaviors, restricted interests, and hyperesthesia/hypesthesia caused by genetic and/or environmental factors. In recent years, inflammation and oxidative stress have been implicated in the pathogenesis of ASD. In this review, we discuss the inflammation and oxidative stress in the pathophysiology of ASD, particularly focusing on maternal immune activation (MIA). MIA is a one of the common environmental risk factors for the onset of ASD during pregnancy. It induces an immune reaction in the pregnant mother’s body, resulting in further inflammation and oxidative stress in the placenta and fetal brain. These negative factors cause neurodevelopmental impairments in the developing fetal brain and subsequently cause behavioral symptoms in the offspring. In addition, we also discuss the effects of anti-inflammatory drugs and antioxidants in basic studies on animals and clinical studies of ASD. Our review provides the latest findings and new insights into the involvements of inflammation and oxidative stress in the pathogenesis of ASD.

Targeting the brain 5-HT7 receptor to prevent hypomyelination in a rodent model of perinatal white matter injuries

Approximately 15 million babies are born prematurely every year and many will face lifetime motor and/or cognitive deficits. Children born prematurely are at higher risk of developing perinatal brain lesions, especially white matter injuries (WMI). Evidence in humans and rodents demonstrates that systemic inflammation-induced neuroinflammation, including microglial and astrocyte reactivity, is the prominent processes of WMI associated with preterm birth. Thus, a new challenge in the field of perinatal brain injuries is to develop new neuroprotective strategies to target neuroinflammation to prevent WMI. Serotonin (5-HT) and its receptors play an important role in inflammation, and emerging evidence indicates that 5-HT may regulate brain inflammation by the modulation of microglial reactivity and astrocyte functions. The present study is based on a mouse model of WMI induced by intraperitoneal (i.p.) injections of IL-1β during the first 5 days of life. In this model, certain key lesions of preterm brain injuries can be summarized by (i) systemic inflammation, (ii) pro-inflammatory microglial and astrocyte activation, and (iii) inhibition of oligodendrocyte maturation, leading to hypomyelination. We demonstrate that Htr7 mRNA (coding for the HTR7/5-HT7 receptor) is significantly overexpressed in the anterior cortex of IL-1β-exposed animals, suggesting it as a potential therapeutic target. LP-211 is a specific high-affinity HTR7 agonist that crosses the blood-brain barrier (BBB). When co-injected with IL-1β, LP-211 treatment prevented glial reactivity, the down-regulation of myelin-associated proteins, and the apparition of anxiety-like phenotypes. Thus, HTR7 may represent an innovative therapeutic target to protect the developing brain from preterm brain injuries.

Comparing autism phenotypes in children born extremely preterm and born at term

Children born preterm are at increased risk for autism spectrum disorder (ASD). There is limited knowledge about whether ASD phenotypes in children born preterm differ from children born at term. The objective of this study was to compare ASD core symptoms and associated characteristics among extremely preterm (EP) and term-born children with ASD. EP participants (n = 59) from the Extremely Low Gestational Age Newborn Study who met diagnostic criteria for ASD at approximately 10 years of age were matched with term-born participants from the Simons Simplex Collection on age, sex, spoken language level, and nonverbal IQ. Core ASD symptomatology was evaluated with the Autism Diagnostic Interview-Revised (ADI-R) and the Autism Diagnostic Observation Schedule (ADOS). Developmental milestones, anthropometrics, seizure disorder, and psychiatric symptoms were also investigated. The EP group had lower parent-reported symptom scores on ADI-R verbal communication, specifically stereotyped language, and restricted, repetitive behaviors. There were no between-group differences on ADI-R nonverbal communication and ADI-R reciprocal social interaction or with direct observation on the ADOS-2. The EP group was more likely to have delayed speech milestones and lower physical growth parameters. Results from female-only analyses were similar to those from whole-group analyses. In sum, behavioral presentation was similar between EP and IQ- and sex-matched term-born children assessed at age 10 years, with the exception of less severe retrospectively reported stereotyped behaviors, lower physical growth parameters, and increased delays in language milestones among EP-born children with ASD.

Effects of Acute and Chronic Trypanosoma cruzi Infection on Pregnancy Outcomes in Mice: Parasite Transmission, Mortality, Delayed Growth, and Organ Damage in Pups

Chagas disease is caused by Trypanosoma cruzi. This study aimed to determine the effects of T. cruzi infection on fertility rate and health of the newborn pups in pregnant mice. Female mice were challenged with T. cruzi and mated at 21 days (acute parasitemic phase) or 90 days (chronic parasite persistence phase) after infection. Pups were examined for growth up to 20 days after birth; and parasite burden in brain, heart, skeletal muscle, and intestine was measured by real-time quantitative PCR. The inflammatory infiltrate, necrosis, and fibrosis in pups' heart and brain tissues were evaluated by histology. T. cruzi infection in dams delayed the onset of pregnancy, decreased the fertility rate, and led to vertical transmission of parasite to the pups. Furthermore, infected dams delivered pups that exhibited decreased survival rate, decreased birth weight, and decreased growth rate. Significantly increased inflammation, necrosis, and fibrosis of cardiac and brain tissues were noted in pups born to infected dams. Initial challenge with higher parasite dose had more detrimental effects on fertility rate and pups' health in both acutely and chronically infected dams. In conclusion, mice offer a promising model to evaluate the efficacy of new vaccines and therapeutic drugs in controlling the acute and chronic maternal T. cruzi infection and congenital transmission to newborns, and in improving the fertility rate and pups' health outcomes.

Autistic traits of children born very preterm assessed using Autism Diagnostic Observation Schedule, Second Edition

Preterm birth has been linked with increased incidence of autism spectrum disorder (ASD). Despite the remarkable difference in the clinical backgrounds between ASD children born preterm and term, cross-sectional studies have found no striking difference in their autistic traits. To highlight autistic traits related with preterm birth, children born very preterm (prospective birth cohort, n = 50) and term (case cohort, n = 16), who were diagnosed as "Autism" by the Autism Diagnostic Observation Schedule (ADOS), 2nd edition, were compared using the calibrated severity scores of ADOS-2 and T-scores of the Social Responsiveness Scale, 2nd edition. No significant difference was found in the calibrated severity scores between ASD children born preterm and term. There was a trend that T-scores were smaller for the preterm cohort, which did not reach a statistical significance. Even when detailed cross-sectional information was obtained using ADOS-2, no difference in autistic traits was observed between children born very preterm and term. Our findings were consistent with a previous study, which assessed the entire prospective cohort of children born very preterm and found no difference in original ADOS scores. Further studies are warranted to delineate how preterm birth affects the autistic traits and their parental perception in a large prospective cohort.

Epigenetic priming of immune/inflammatory pathways activation and abnormal activity of cell cycle pathway in a perinatal model of white matter injury

Prenatal inflammatory insults accompany prematurity and provoke diffuse white matter injury (DWMI), which is associated with increased risk of neurodevelopmental pathologies, including autism spectrum disorders. DWMI results from maturation arrest of oligodendrocyte precursor cells (OPCs), a process that is poorly understood. Here, by using a validated mouse model of OPC maturation blockade, we provide the genome-wide ID card of the effects of neuroinflammation on OPCs that reveals the architecture of global cell fate issues underlining their maturation blockade. First, we find that, in OPCs, neuroinflammation takes advantage of a primed epigenomic landscape and induces abnormal overexpression of genes of the immune/inflammatory pathways: these genes strikingly exhibit accessible chromatin conformation in uninflamed OPCs, which correlates with their developmental, stage-dependent expression, along their normal maturation trajectory, as well as their abnormal upregulation upon neuroinflammation. Consistently, we observe the positioning on DNA of key transcription factors of the immune/inflammatory pathways (IRFs, NFkB), in both unstressed and inflamed OPCs. Second, we show that, in addition to the general perturbation of the myelination program, neuroinflammation counteracts the physiological downregulation of the cell cycle pathway in maturing OPCs. Neuroinflammation therefore perturbs cell identity in maturing OPCs, in a global manner. Moreover, based on our unraveling of the activity of genes of the immune/inflammatory pathways in prenatal uninflamed OPCs, the mere suppression of these proinflammatory mediators, as currently proposed in the field, may not be considered as a valid neurotherapeutic strategy.

Atypical brain network development of infants at elevated likelihood for autism spectrum disorder during the first year of life

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by behavioral features that appear early in life. Although studies have shown that atypical brain functional and structural connectivity are associated with these behavioral traits, the occurrence and initial alterations of brain networks have not been fully investigated. The current study aimed to map early brain network efficiency and information transferring in infants at elevated likelihood (EL) compared to infants at typical likelihood (TL) for ASD in the first year of life. This study used a resting-state functional near-infrared spectroscopy (fNIRS) approach to obtain the length and strength of functional connections in the frontal and temporal areas in 45 5-month-old and 38 10-month-old infants. Modular organization and small-world properties were detected in both EL and TL infants at 5 and 10 months. In 5-month-old EL infants, local and nodal efficiency were significantly greater than age-matched TL infants, indicating overgrown local connections. Furthermore, we used a support vector machine (SVM) model to classify infants with or without EL based on the obtained global properties of the network, achieving an accuracy of 77.6%. These results suggest that infants with EL for ASD exhibit inefficiencies in the organization of brain networks during the first year of life.

Adult outcome of preterm birth: Implications for neurodevelopmental theories of psychosis

Preterm birth is associated with an elevated risk of developmental and adult psychiatric disorders, including psychosis. In this review, we evaluate the implications of neurodevelopmental, cognitive, motor, and social sequelae of preterm birth for developing psychosis, with an emphasis on outcomes observed in adulthood. Abnormal brain development precipitated by early exposure to the extra-uterine environment, and exacerbated by neuroinflammation, neonatal brain injury, and genetic vulnerability, can result in alterations of brain structure and function persisting into adulthood. These alterations, including abnormal regional brain volumes and white matter macro- and micro-structure, can critically impair functional (e.g. frontoparietal and thalamocortical) network connectivity in a manner characteristic of psychotic illness. The resulting executive, social, and motor dysfunctions may constitute the basis for behavioural vulnerability ultimately giving rise to psychotic symptomatology. There are many pathways to psychosis, but elucidating more precisely the mechanisms whereby preterm birth increases risk may shed light on that route consequent upon early neurodevelopmental insult.

Sex dependent glio-vascular interface abnormality in the hippocampus following postnatal immune activation in mice

The neuro-gliovascular unit is a crucial structure for providing a balanced well-functioning environment for neurons and their synapses. Activation of the immune system during the developmental period is believed to affect the gliovascular unit, which may trigger neurodevelopmental and neurological/neuropsychiatric diseases. In this study, we hypothesized that vulnerability of the male brain to a neonatal insult was conditioned by sex-dependent differences in the impairment of the hippocampal gliovascular unit. Male and female C57BL/6J pups received lipopolysaccharide (LPS) (1 mg/kg) or saline on postnatal day (P) 5. Brains were collected at P12 and morphological quantifications of hippocampal fibrillary glial acid protein (GFAP⁺) astrocytes and ionized calcium-binding adaptor molecule 1 protein (Iba1+) microglia were performed by using 3-D image analysis together with measuring the length of CD31⁺ and aquaporin-4 (AQP4⁺) vessels. We found a significant increase in the length of CD31⁺ capillaries in the male LPS group compared to the saline group; however, coverage of capillaries by astrocytic end-feet (AQP4⁺) was significantly reduced. In contrast, there was a significant increase in AQP4⁺ capillary length in female pups 1 week after LPS injection. GFAP⁺ astrocytes via morphological changes in the hippocampus showed significant enhancement in the activity 1 week following LPS injection in male mice. We propose that neonatal inflammation could induce susceptibility to neurodevelopmental disorders through modification of hippocampal gliovascular interface in a sex-dependent manner.

Vagus nerve stimulated by microbiota-derived hydrogen sulfide mediates the regulation of berberine on microglia in transient middle cerebral artery occlusion rats

Amelioration of neuroinflammation via modulating microglia is a promising approach for cerebral ischemia therapy. The aim of the present study was to explore gut-brain axis signals in berberine-modulating microglia polarization following cerebral ischemia. The potential pathway was determined through analyzing the activation of the vagus nerve, hydrogen sulfide (H₂ S) metabolism, and cysteine persulfides of transient receptor potential vanilloid 1 (TRPV1) receptor. The cerebral microenvironment feature was explored with a metabolomics assay. The data indicated that berberine ameliorated behavioral deficiency in transient middle cerebral artery occlusion rats through modulating microglia polarization and neuroinflammation depending on microbiota. Enhanced vagus nerve activity following berberine treatment was blocked by antibiotic cocktails, capsazepine, or sodium molybdate, respectively. Berberine-induced H₂ S production was responsible for vagus nerve stimulation achieved through assimilatory and dissimilatory sulfate reduction with increased synthetic enzymes. Sulfation of the TRPV1 receptor resulted in vagus nerve activation and promoted the c-fos and ChAT in the nucleus tractus solitaries with berberine. Sphingolipid metabolism is the primary metabolic characteristic with berberine in the cerebral cortex, hippocampus, and cerebral spinal fluid disrupted by antibiotics. Berberine, in conclusion, modulates microglia polarization in a microbiota-dependent manner. H₂ S stimulates the vagus nerve through TRPV1 is responsible for the berberine-induced gut-brain axis signal transmission. Sphingolipid metabolism might mediate the neuroinflammation amelioration following vagus afferent fiber activation.

White Matter Injury in Preterm Infants: Pathogenesis and Potential Therapy From the Aspect of the Gut–Brain Axis

Very preterm infants who survive are at high risk of white matter injury (WMI). With a greater understanding of the pathogenesis of WMI, the gut microbiota has recently drawn increasing attention in this field. This review tries to clarify the possible mechanisms behind the communication of the gut bacteria and the immature brain via the gut–brain axis. The gut microbiota releases signals, such as microbial metabolites. These metabolites regulate inflammatory and immune responses characterized by microglial activation, which ultimately impact the differentiation of pre-myelinating oligodendrocytes (pre-OLs) and lead to WMI. Moreover, probiotics and prebiotics emerge as a promising therapy to improve the neurodevelopmental outcome. However, future studies are required to clarify the function of these above products and the optimal time for their administration within a larger population. Based on the existing evidence, it is still too early to recommend probiotics and prebiotics as effective treatments for WMI.

The Impact of Mouse Preterm Birth Induction by RU-486 on Microglial Activation and Subsequent Hypomyelination

Preterm birth (PTB) represents 15 million births every year worldwide and is frequently associated with maternal/fetal infections and inflammation, inducing neuroinflammation. This neuroinflammation is mediated by microglial cells, which are brain-resident macrophages that release cytotoxic molecules that block oligodendrocyte differentiation, leading to hypomyelination. Some preterm survivors can face lifetime motor and/or cognitive disabilities linked to periventricular white matter injuries (PWMIs). There is currently no recommendation concerning the mode of delivery in the case of PTB and its impact on brain development. Many animal models of induced-PTB based on LPS injections exist, but with a low survival rate. There is a lack of information regarding clinically used pharmacological substances to induce PTB and their consequences on brain development. Mifepristone (RU-486) is a drug used clinically to induce preterm labor. This study aims to elaborate and characterize a new model of induced-PTB and PWMIs by the gestational injection of RU-486 and the perinatal injection of pups with IL-1beta. A RU-486 single subcutaneous (s.c.) injection at embryonic day (E)18.5 induced PTB at E19.5 in pregnant OF1 mice. All pups were born alive and were adopted directly after birth. IL-1beta was injected intraperitoneally from postnatal day (P)1 to P5. Animals exposed to both RU-486 and IL-1beta demonstrated microglial reactivity and subsequent PWMIs. In conclusion, the s.c. administration of RU-486 induced labor within 24 h with a high survival rate for pups. In the context of perinatal inflammation, RU-486 labor induction significantly decreases microglial reactivity in vivo but did not prevent subsequent PWMIs.

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.

Prediction Effect of Amplitude-Integrated EEG on the Brain Damage and Long-Term Nervous System Development of Late Preterm Infants

In order to explore the prediction effect of amplitude-integrated EEG on the brain damage and long-term nervous system development of late preterm infants, this paper uses the hospital's late preterm infants as the research object and analyzes the prediction effect of amplitude-integrated EEG on the brain damage and long-term nervous system development of late preterm infants through controlled trials. Among them, the test group used amplitude-integrated EEG for prediction analysis, and the control group used traditional clinical prediction methods. Furthermore, the real-time monitoring and short-term prediction effects of amplitude-integrated EEG on brain damage in late preterm babies and the prediction impact on long-term nervous system development are evaluated in this study. It incorporates statistical techniques to evaluate the findings statistically. In addition, a nonparametric rank-sum test is used in this work, and a chi-square test is used to compare enumeration data across groups. Through experimental research, it can be seen that the amplitude-integrated EEG has a pronounced prediction effect on the brain damage and long-term nervous system development of late preterm infants, and the effect is higher than that of the traditional clinical prediction methods.

Expression of IL-20 Receptor Subunit β Is Linked to EAE Neuropathology and CNS Neuroinflammation

Considerable clinical evidence supports that increased blood-brain barrier (BBB) permeability is linked to immune extravasation of CNS parenchyma during neuroinflammation. Although BBB permeability and immune extravasation are known to be provoked by vascular endothelial growth factor-A (i.e., VEGF-A) and C-X-C motif chemokine ligand 12 (CXCL12), respectively, the mechanisms that link both processes are still elusive. The interleukin-20 (i.e., IL-20) cytokine signaling pathway was previously implicated in VEGF-mediated angiogenesis and is known to induce cellular response by way of signaling through IL-20 receptor subunit β (i.e., IL-20RB). Dysregulated IL-20 signaling is implicated in many inflammatory pathologies, but it's contribution to neuroinflammation has yet to be reported. We hypothesize that the IL-20 cytokine, and the IL cytokine subfamily more broadly, play a key role in CNS neuroinflammation by signaling through IL-20RB, induce VEGF activity, and enhance both BBB-permeability and CXCL12-mediated immune extravasation. To address this hypothesis, we actively immunized IL-20RB^-/- mice and wild-type mice to induce experimental autoimmune encephalomyelitis (EAE) and found that IL-20RB^-/- mice showed amelioration of disease progression compared to wild-type mice. Similarly, we passively immunized IL-20RB^-/- mice and wild-type mice with myelin-reactive Th1 cells from either IL-20RB^-/- and wild-type genotype. Host IL-20RB^-/- mice showed lesser disease progression than wild-type mice, regardless of the myelin-reactive Th1 cells genotype. Using multianalyte bead-based immunoassay and ELISA, we found distinctive changes in levels of pro-inflammatory cytokines between IL-20RB^-/- mice and wild-type mice at peak of EAE. We also found detectable levels of all cytokines of the IL-20 subfamily within CNS tissues and specific alteration to IL-20 subfamily cytokines IL-19, IL-20, and IL-24, expression levels. Immunolabeling of CNS region-specific microvessels confirmed IL-20RB protein at the spinal cord microvasculature and upregulation during EAE. Microvessels isolated from macaques CNS tissues also expressed IL-20RB. Moreover, we identified the expression of all IL-20 receptor subunits: IL-22 receptor subunit α-1 (IL-22RA1), IL-20RB, and IL-20 receptor subunit α (IL-20RA) in human CNS microvessels. Notably, human cerebral microvasculature endothelial cells (HCMEC/D3) treated with IL-1β showed augmented expression of the IL-20 receptor. Lastly, IL-20-treated HCMEC/D3 showed alterations on CXCL12 apicobasal polarity consistent with a neuroinflammatory status. This evidence suggests that IL-20 subfamily cytokines may signal at the BBB via IL-20RB, triggering neuroinflammation.

Neuroprotection offered by mesenchymal stem cells in perinatal brain injury: Role of mitochondria, inflammation, and reactive oxygen species

Preclinical studies have shown that mesenchymal stem cells have a positive effect in perinatal brain injury models. The mechanisms that cause these neurotherapeutic effects are not entirely intelligible. Mitochondrial damage, inflammation, and reactive oxygen species are considered to be critically involved in the development of injury. Mesenchymal stem cells have immunomodulatory action and exert mitoprotective effects which attenuate production of reactive oxygen species and promote restoration of tissue function and metabolism after perinatal insults. This review summarizes the present state, the underlying causes, challenges and possibilities for effective clinical translation of mesenchymal stem cell therapy.

Women with high plasma levels of PBDE-47 are at increased risk of preterm birth

OBJECTIVES

Nearly 100% of North American women have detectable levels of flame retardants such as polybrominated diphenyl ethers (PBDEs) in their plasma. These molecules have structural homology to thyroid hormones and may function as endocrine disruptors. Thyroid dysfunction has previously been associated with increased risk for preterm birth. Therefore, we conducted a multi-center, case-cohort study to evaluate if high plasma concentrations of a common PBDE congener in the first trimester increases the risk of preterm birth and its subtypes.

METHODS

Pregnant women were recruited at the onset of initiation of prenatal care at Kaiser-Permanente Southern California (KPSC)-West Los Angeles and KPSC-San Diego medical centers. Plasma samples from women whose pregnancies ended preterm and random subset of those delivering at term were assayed for PBDE-47 and thyroid-stimulating hormone (TSH) by immunoassay. Quartile cutoffs were calculated for the patients at term and used to determine if women with exposures in the 4th quartile are at increased risk for preterm birth using logistic regression.

RESULTS

We found that high concentrations of PBDE-47 in the first trimester significantly increased the odds of both indicated (adjusted odds ratio, adjOR=2.35, 95% confidence interval [CI]: 1.31, 4.21) and spontaneous (adjOR=1.76, 95% CI: 1.02, 3.03) preterm birth. Regardless of pregnancy outcome, TSH concentrations did not differ between women with high and low concentrations of PBDE-47.

CONCLUSIONS

These results suggest that high plasma concentrations of PBDE-47 in the first trimester, increases the risk of indicated and spontaneous preterm birth.

Whether erythropoietin can be a neuroprotective agent against premature brain injury: cellular mechanisms and clinical efficacy

Preterm infants are at high risk of brain injury. With more understanding of the preterm brain injury's pathogenesis, neuroscientists are looking for more effective methods to prevent and treat it, among which erythropoietin (Epo) is considered as a prime candidate. This review tries to clarify the possible mechanisms of Epo in preterm neuroprotection and summarize updated evidence considering Epo as a pharmacological neuroprotective strategy in animal models and clinical trials. To date, various animal models have validated that Epo is an anti-apoptotic, anti-inflammatory, anti-oxidant, anti-excitotoxic, neurogenetic, erythropoietic, angiogenetic, and neurotrophic agent, thus preventing preterm brain injury. However, although the scientific rationale and preclinical data for Epo's neuroprotective effect are promising, when translated to bedside, the results vary in different studies, especially in its long-term efficacy. Based on existing evidence, it is still too early to recommend Epo as the standard treatment for preterm brain injury.

Anti-Inflammatory Therapies for Treatment of Inflammation-Related Preterm Brain Injury

Despite the prevalence of preterm brain injury, there are no established neuroprotective strategies to prevent or alleviate mild-to-moderate inflammation-related brain injury. Perinatal infection and inflammation have been shown to trigger acute neuroinflammation, including proinflammatory cytokine release and gliosis, which are associated with acute and chronic disturbances in brain cell survival and maturation. These findings suggest the hypothesis that the inhibition of peripheral immune responses following infection or nonspecific inflammation may be a therapeutic strategy to reduce the associated brain injury and neurobehavioral deficits. This review provides an overview of the neonatal immunity, neuroinflammation, and mechanisms of inflammation-related brain injury in preterm infants and explores the safety and efficacy of anti-inflammatory agents as potentially neurotherapeutics.

Neurotrophic Factor Levels in Preterm Infants: A Systematic Review and Meta-Analysis

Objectives: Through a systematic review and meta-analysis of the literature we aimed to compare the levels of BDNF, NGF, NT-3, NT-4, and GDNF between human term and preterm infants, and investigate factors implicated in the variability of effect size estimates. Methods: The analysis was performed in three online databases, MEDLINE Complete, PsycINFO, and CINAHL. A random effects model was used to calculate the standardized mean difference (SMD) of neurotrophic factor levels in preterm infants vs. term within a 95% confidence interval (CI). To explore sources of heterogeneity meta-regression models were implemented. Results: Sixteen studies were included in this meta-analysis. A combined sample of 1,379 preterm and 1,286 term newborns were evaluated. We identified significant lower BDNF (SMD = -0.32; 95% CI: -0.59, -0.06; p = 0.014) and NT-3 (SMD = -0.31; 95% CI: -0.52, -0.09; p = 0.004) levels in preterm compared to term infants. No significant difference was observed in NGF and NT-4 levels between groups. Given that only two effect sizes were generated for GDNF levels, no meta-analytical model was performed. Meta-regression models revealed sample type (placental tissue, cerebrospinal fluid, peripheral blood, and umbilical cord blood) as a significant moderator of heterogeneity for BDNF meta-analysis. No significant associations were found for gestational week, birth weight, and clinical comorbidity of newborns with effect sizes. Conclusions: Our findings indicated that lower BDNF and NT-3 levels may be associated with preterm birth. Future studies with larger samples sizes should investigate neurodevelopmental manifestations resulting from neurotrophic factor dysregulation among preterm infants.

The immune-inflammatory response of oligodendrocytes in a murine model of preterm white matter injury: the role of TLR3 activation

A leading cause of preterm birth is the exposure to systemic inflammation (maternal/fetal infection), which leads to neuroinflammation and white matter injury (WMI). A wide range of cytokines and chemokines are expressed and upregulated in oligodendrocytes (OLs) in response to inflammation and numerous reports show that OLs express several receptors for immune related molecules, which enable them to sense inflammation and to react. However, the role of OL immune response in WMI is unclear. Here, we focus our study on toll-like receptor-3 (TLR3) that is activated by double-strand RNA (dsRNA) and promotes neuroinflammation. Despite its importance, its expression and role in OLs remain unclear. We used an in vivo mouse model, which mimics inflammation-mediated WMI of preterm born infants consisting of intraperitoneal injection of IL-1β from P1 to P5. In the IL-1β-treated animals, we observed the upregulation of Tlr3, IL-1β, IFN-β, Ccl2, and Cxcl10 in both PDGFRα+ and O4+ sorted cells. This upregulation was higher in O4+ immature OLs (immOLs) as compared to PDGFRα+ OL precursor cells (OPCs), suggesting a different sensitivity to neuroinflammation. These observations were confirmed in OL primary cultures: cells treated with TLR3 agonist Poly(I:C) during differentiation showed a stronger upregulation of Ccl2 and Cxcl10 compared to cells treated during proliferation and led to decreased expression of myelin genes. Finally, OLs were able to modulate microglia phenotype and function depending on their maturation state as assessed by qPCR using validated markers for immunomodulatory, proinflammatory, and anti-inflammatory phenotypes and by phagocytosis and morphological analysis. These results show that during inflammation the response of OLs can play an autonomous role in blocking their own differentiation: in addition, the immune activation of OLs may play an important role in shaping the response of microglia during inflammation.

Microglia-Mediated Neurodegeneration in Perinatal Brain Injuries

Perinatal brain injuries, including encephalopathy related to fetal growth restriction, encephalopathy of prematurity, neonatal encephalopathy of the term neonate, and neonatal stroke, are a major cause of neurodevelopmental disorders. They trigger cellular and molecular cascades that lead in many cases to permanent motor, cognitive, and/or behavioral deficits. Damage includes neuronal degeneration, selective loss of subclasses of interneurons, blocked maturation of oligodendrocyte progenitor cells leading to dysmyelination, axonopathy and very likely synaptopathy, leading to impaired connectivity. The nature and severity of changes vary according to the type and severity of insult and maturation stage of the brain. Microglial activation has been demonstrated almost ubiquitously in perinatal brain injuries and these responses are key cell orchestrators of brain pathology but also attempts at repair. These divergent roles are facilitated by a diverse suite of transcriptional profiles and through a complex dialogue with other brain cell types. Adding to the complexity of understanding microglia and how to modulate them to protect the brain is that these cells have their own developmental stages, enabling them to be key participants in brain building. Of note, not only do microglia help build the brain and respond to brain injury, but they are a key cell in the transduction of systemic inflammation into neuroinflammation. Systemic inflammatory exposure is a key risk factor for poor neurodevelopmental outcomes in preterm born infants. Based on these observations, microglia appear as a key cell target for neuroprotection in perinatal brain injuries. Numerous strategies have been developed experimentally to modulate microglia and attenuate brain injury based on these strong supporting data and we will summarize these.

Placental programming, perinatal inflammation, and neurodevelopment impairment among those born extremely preterm

Individuals born extremely preterm are at significant risk for impaired neurodevelopment. After discharge from the neonatal intensive care, associations between the child's well-being and factors in the home and social environment become increasingly apparent. Mothers' prenatal health and socioeconomic status are associated with neurodevelopmental outcomes, and emotional and behavioral problems. Research on early life risk factors and on mechanisms underlying inter-individual differences in neurodevelopment later in life can inform the design of personalized approaches to prevention. Here, we review early life predictors of inter-individual differences in later life neurodevelopment among those born extremely preterm. Among biological mechanisms that mediate relationships between early life predictors and later neurodevelopmental outcomes, we highlight evidence for disrupted placental processes and regulated at least in part via epigenetic mechanisms, as well as perinatal inflammation. In relation to these mechanisms, we focus on four prenatal antecedents of impaired neurodevelopment, namely, (1) fetal growth restriction, (2) maternal obesity, (3) placental microorganisms, and (4) socioeconomic adversity. In the future, this knowledge may inform efforts to detect and prevent adverse outcomes in infants born extremely preterm. IMPACT: This review highlights early life risk factors and mechanisms underlying inter-individual differences in neurodevelopment later in life. The review emphasizes research on early life risk factors (fetal growth restriction, maternal obesity, placental microorganisms, and socioeconomic adversity) and on mechanisms (disrupted placental processes and perinatal inflammation) underlying inter-individual differences in neurodevelopment later in life. The findings highlighted here may inform efforts to detect and prevent adverse outcomes in infants born extremely preterm.

Current Approaches to the Pharmacologic Treatment of Core Symptoms Across the Lifespan of Autism Spectrum Disorder

There are no approved medications for autism spectrum disorder (ASD) core symptoms. However, given the significant clinical need, children and adults with ASD are prescribed medication off label for core or associated conditions, sometimes based on limited evidence for effectiveness. Recent developments in the understanding of biologic basis of ASD have led to novel targets with potential to impact core symptoms, and several clinical trials are underway. Heterogeneity in course of development, co-occurring conditions, and age-related treatment response variability hampers study outcomes. Novel measures and approaches to ASD clinical trial design will help in development of effective pharmacologic treatments.

Midkine: The Who, What, Where, and When of a Promising Neurotrophic Therapy for Perinatal Brain Injury

Midkine (MK) is a small secreted heparin-binding protein highly expressed during embryonic/fetal development which, through interactions with multiple cell surface receptors promotes growth through effects on cell proliferation, migration, and differentiation. MK is upregulated in the adult central nervous system (CNS) after multiple types of experimental injury and has neuroprotective and neuroregenerative properties. The potential for MK as a therapy for developmental brain injury is largely unknown. This review discusses what is known of MK's expression and actions in the developing brain, areas for future research, and the potential for using MK as a therapeutic agent to ameliorate the effects of brain damage caused by insults such as birth-related hypoxia and inflammation.

Dysfunctional proteins in neuropsychiatric disorders: From neurodegeneration to autism spectrum disorders

Despite fundamental differences in disease course and outcomes, neurodevelopmental (autism spectrum disorders - ASD) and neurodegenerative disorders (Alzheimer's disease - AD and Parkinson's disease - PD) present surprising, common traits in their molecular pathomechanisms. Uncontrolled oligomerization and aggregation of amyloid β (Aβ), microtubule-associated protein (MAP) tau, or α-synuclein (α-syn) contribute to synaptic impairment and the ensuing neuronal death in both AD and PD. Likewise, the pathogenesis of ASD may be attributed, at least in part, to synaptic dysfunction; attention has also been recently paid to irregularities in the metabolism and function of the Aβ precursor protein (APP), tau, or α-syn. Commonly affected elements include signaling pathways that regulate cellular metabolism and survival such as insulin/insulin-like growth factor (IGF) - PI3 kinase - Akt - mammalian target of rapamycin (mTOR), and a number of key synaptic proteins critically involved in neuronal communication. Understanding how these shared pathomechanism elements operate in different conditions may help identify common targets and therapeutic approaches.