Neuroinflammation in autism spectrum disorders

Cellular stress mechanisms of prenatal maternal stress: Heat shock factors and oxidative stress

Development of the brain prenatally is affected by maternal experience and exposure. Prenatal maternal psychological stress changes brain development and results in increased risk for neuropsychiatric disorders. In this review, multiple levels of prenatal stress mechanisms (offspring brain, placenta, and maternal physiology) are discussed and their intersection with cellular stress mechanisms explicated. Heat shock factors and oxidative stress are closely related to each other and converge with the inflammation, hormones, and cellular development that have been more deeply explored as the basis of prenatal stress risk. Increasing evidence implicates cellular stress mechanisms in neuropsychiatric disorders associated with prenatal stress including affective disorders, schizophrenia, and child-onset psychiatric disorders. Heat shock factors and oxidative stress also have links with the mechanisms involved in other kinds of prenatal stress including external exposures such as environmental toxicants and internal disruptions such as preeclampsia. Integrative understanding of developmental neurobiology with these cellular and physiological mechanisms is necessary to reduce risks and promote healthy brain development.

Anti-inflammatory cytokines in autism spectrum disorders: A systematic review and meta-analysis

BACKGROUND

In the search for the causes of autism spectrum disorders (ASD), inflammatory markers have emerged as potential candidates. The present meta-analysis was performed on studies examining circulating concentrations of anti-inflammatory cytokines in people with ASD compared with control subjects without ASD.

METHODS

We identified potentially eligible studies by systematically searching electronic databases from inception to February 2018.

RESULTS

Twenty-five studies with a total of 1754 participants (1022 patients with ASD and 732 control subjects) were included in the mate-analysis; 4 for interferon (IFN)-α, 9 for interleukin (IL)-1 receptor antagonist (Ra), 9 for IL-4, 6 for IL-5, 3 for IL-9, 14 for IL-10, 7 for IL-13, and 6 for transforming growth factor (TGF)-β. We found a moderate decrease in plasma levels of IL-10 (SMD = -0.59) and a small decrease in serum levels of IL-1Ra (SMD = -0.25) in patients with ASD. On the contrary, serum IL-5 levels were slightly increased (SMD = 0.26) in these patients. We conducted meta-regression analyses to investigate the possible effect of moderatos on the effect size (ES) of difference in mean levels of IL-10. Difference in the mean age between patients and controls showed a negative influence on the ES and was able to explain about 0.4 of total between-study variance. In contrast, latitude exerted a positive effect on the ES and explained a lower proportion (0.1) of total between-study variance.

CONCLUSIONS

This meta-analysis provides evidence for the lower concentration of anti-inflammatory cytokines IL-10 and IL-1Ra in autistic patients compared with control subjects. Also, meta-regression analyses point to the interaction of latitude, age, and gender with peripheral alterations of associated anti-inflammatory cytokines.

α7 Nicotinic Acetylcholine Receptor Signaling Modulates Ovine Fetal Brain Astrocytes Transcriptome in Response to Endotoxin

Neuroinflammation in utero may result in lifelong neurological disabilities. Astrocytes play a pivotal role in this process, but the mechanisms are poorly understood. No early postnatal treatment strategies exist to enhance neuroprotective potential of astrocytes. We hypothesized that agonism on α7 nicotinic acetylcholine receptor (α7nAChR) in fetal astrocytes will augment their neuroprotective transcriptome profile, while the inhibition of α7nAChR will achieve the opposite. Using an in vivo–in vitro model of developmental programming of neuroinflammation induced by lipopolysaccharide (LPS), we validated this hypothesis in primary fetal sheep astrocytes cultures re-exposed to LPS in the presence of a selective α7nAChR agonist or antagonist. Our RNAseq findings show that a pro-inflammatory astrocyte transcriptome phenotype acquired in vitro by LPS stimulation is reversed with α7nAChR agonistic stimulation. Conversely, α7nAChR inhibition potentiates the pro-inflammatory astrocytic transcriptome phenotype. Furthermore, we conducted a secondary transcriptome analysis against the identical α7nAChR experiments in fetal sheep primary microglia cultures. Similar to findings in fetal microglia, in fetal astrocytes we observed a memory effect of in vivo exposure to inflammation, expressed in a perturbation of the iron homeostasis signaling pathway (hemoxygenase 1, HMOX1), which persisted under pre-treatment with α7nAChR antagonist but was reversed with α7nAChR agonist. For both glia cell types, common pathways activated due to LPS included neuroinflammation signaling and NF-κB signaling in some, but not all comparisons. However, overall, the overlap on the level of signaling pathways was rather minimal. Astrocytes, not microglia—the primary immune cells of the brain, were characterized by unique inhibition patterns of STAT3 pathway due to agonistic stimulation of α7nAChR prior to LPS exposure. Lastly, we discuss the implications of our findings for fetal and postnatal brain development.

Impact of Auditory Integration Therapy (AIT) on the Plasma Levels of Human Glial Cell Line-Derived Neurotrophic Factor (GDNF) in Autism Spectrum Disorder

Neurotrophic factors, including the glial cell line-derived neurotrophic factor (GDNF), are of importance for synaptic plasticity regulation, intended as the synapses' ability to strengthen or weaken their responses to differences in neuronal activity. Such plasticity is essential for sensory processing, which has been shown to be impaired in autism spectrum disorder (ASD). This study is the first to investigate the impact of auditory integration therapy (AIT) of sensory processing abnormalities in autism on plasma GDNF levels. Fifteen ASD children, aged between 5 and 12 years, were enrolled and underwent the present research study. AIT was performed throughout 10 days with a 30-min session twice a day. Before and after AIT, Childhood Autism Rating Scale (CARS), Social Responsiveness Scale (SRS), and Short Sensory Profile (SSP) scores were calculated, and plasma GDNF levels were assayed by an EIA test. A substantial decline in autistic behavior was observed after AIT in the scaling parameters used. Median plasma GDNF level was 52.142 pg/ml before AIT. This level greatly increased immediately after AIT to 242.05 pg/ml (P < 0.001). The levels were depressed to 154.00 pg/ml and 125.594 pg/ml 1 month and 3 months later, respectively, but they were still significantly higher compared with the levels before the treatment (P = 0.001, P = 0.01, respectively). There was an improvement in the measures of autism severity as an effect of AIT which induced the up-regulation of GDNF in plasma. Further research, on a large scale, is needed to evaluate if the cognitive improvement of ASD children after AIT is related or not connected to the up-regulation of GDNF.

Association between high levels of inflammatory markers and cognitive outcomes at 4 years of age: The Rhea mother-child cohort study, Crete, Greece

There is growing evidence associating inflammatory markers in complex, higher order neurological functions, such as cognition and memory. We examined whether high levels of various inflammatory markers are associated with cognitive outcomes at 4 years of age in a mother-child cohort in Crete, Greece (Rhea study). We included 642 children in this cross-sectional study. Levels of several inflammatory markers (IFN-γ, IL-1β, IL-6, IL-8, IL-17α, IL-10, MIP-1α, TNF-α and the ratios of IL-6 to IL-10 and TNF-α to IL-10) were determined in child serum via immunoassay. Neurodevelopment at 4 years was assessed by means of the McCarthy Scales of Children's Abilities. Multivariate linear regression analyses were used to estimate the associations between the exposures and outcomes of interest after adjustment for various confounders. Our results indicate that children with high TNF-α concentrations (≥90th percentile) in serum demonstrated decreased scores in memory (adjusted β = -4.0; 95% CI: -7.7, -0.2), working memory (adjusted β = -4.0; 95% CI: -8.0, -0.1) as well as in memory span scale (adjusted β = -4.0; 95% CI: -7.9, -0.1). We also found that children with high IFN-γ serum levels showed lower scores in memory span scale (adjusted β = -3.4; 95% CI: -7.3, -0.4). Children with elevated TNF-α/IL-10 ratio demonstrated decreased quantitative (adjusted β = -4.3; 95% CI: -8.2, -0.4), motor (adjusted β = -3.5; 95% CI: -7.5, -0.5), executive function (adjusted β = -4.8; 95% CI: -8.5, -1.1), general cognitive (adjusted β = -3.6; 95% CI: -7.3, -0.1), memory (adjusted β = -3.8; 95% CI: -7.6, -0), working memory (adjusted β = -3.5; 95% CI: -7.5, -0.5) and memory span scores (adjusted β = -5.3; 95% CI: -9.1, -1.4) The findings suggest that high levels of TNF-α may contribute to reduced memory performance at preschool age.

The Contribution of Fluoride to the Pathogenesis of Eye Diseases: Molecular Mechanisms and Implications for Public Health

This study provides diverse lines of evidence demonstrating that fluoride (F) exposure contributes to degenerative eye diseases by stimulating or inhibiting biological pathways associated with the pathogenesis of cataract, age-related macular degeneration and glaucoma. As elucidated in this study, F exerts this effect by inhibiting enolase, τ-crystallin, Hsp40, Na⁺, K⁺-ATPase, Nrf2, γ -GCS, HO-1 Bcl-2, FoxO1, SOD, PON-1 and glutathione activity, and upregulating NF-κB, IL-6, AGEs, HsP27 and Hsp70 expression. Moreover, F exposure leads to enhanced oxidative stress and impaired antioxidant activity. Based on the evidence presented in this study, it can be concluded that F exposure may be added to the list of identifiable risk factors associated with pathogenesis of degenerative eye diseases. The broader impact of these findings suggests that reducing F intake may lead to an overall reduction in the modifiable risk factors associated with degenerative eye diseases. Further studies are required to examine this association and determine differences in prevalence rates amongst fluoridated and non-fluoridated communities, taking into consideration other dietary sources of F such as tea. Finally, the findings of this study elucidate molecular pathways associated with F exposure that may suggest a possible association between F exposure and other inflammatory diseases. Further studies are also warranted to examine these associations.

Neurobiology and Therapeutic Potential of Cyclooxygenase-2 (COX-2) Inhibitors for Inflammation in Neuropsychiatric Disorders

Neuropsychiatric disorders, such as depression, bipolar disorder, schizophrenia, obsessive-compulsive disorder, and neurodevelopmental disorders such as autism spectrum disorder, are associated with significant illness burden. Accumulating evidence supports an association between these disorders and inflammation. Consequently, anti-inflammatory agents, such as the cyclooxygenase-2 inhibitors, represent a novel avenue to prevent and treat neuropsychiatric illness. In this paper, we first review the role of inflammation in psychiatric pathophysiology including inflammatory cytokines' influence on neurotransmitters, the hypothalamic-pituitary-adrenal axis, and microglial mechanisms. We then discuss how cyclooxygenase-2-inhibitors influence these pathways with potential therapeutic benefit, with a focus on celecoxib, due to its superior safety profile. A search was conducted in PubMed, Embase, and PsychINFO databases, in addition to Clinicaltrials.gov and the Stanley Medical Research Institute trial registries. The results were presented as a narrative review. Currently available outcomes for randomized controlled trials up to November 2017 are also discussed. The evidence reviewed here suggests cyclooxygenase-2 inhibitors, and in particular celecoxib, may indeed assist in treating the symptoms of neuropsychiatric disorders; however, further studies are required to assess appropriate illness stage-related indication.

Do Alarmins Have a Potential Role in Autism Spectrum Disorders Pathogenesis and Progression?

Autism spectrum disorders (ASDs) represent a disabling condition in early childhood. A number of risk factors were proposed in order to explain their pathogenesis. A multifactorial model was proposed, and data supported the implication of genetic and environmental factors. One of the most accepted speculations is the existence of an imbalance of the immune system. Altered levels of cytokines, chemokines and immunoglobulins were demonstrated in patients with ASDs; in particular, proinflammatory mediators were significantly increased. Alarmins are a multifunctional heterogeneous group of proteins, structurally belonging to specific cells or incorporated by them. They are released in the surrounding tissues as a consequence of cell damage or inflammation. Their functions are multiple as they could activate innate immunity or recruit and activate antigen-presenting cells stimulating an adaptive response. Alarmins are interesting both for understanding the inflammatory process and for diagnostic purposes as biomarkers. Moreover, recent studies, separately, showed that alarmins like interleukin (IL)-33, high-mobility group box 1 (HMGB1), heat-shock protein (HSP) and S100 protein (S100) could play a relevant role in the pathogenesis of ASDs. According to the literature, some of these alarmins could be suitable as biomarkers of inflammation in ASD. Other alarmins, by interfering with the immune system blocking pro-inflammatory mediators, could be the key for ameliorating symptoms and behaviours in autistic disorders.

Immune Abnormalities in Autism Spectrum Disorder-Could They Hold Promise for Causative Treatment?

Autism spectrum disorders (ASD) are characterized by impairments in language and communication development, social behavior, and the occurrence of stereotypic patterns of behavior and interests. Despite substantial speculation about causes of ASD, its exact etiology remains unknown. Recent studies highlight a link between immune dysfunction and behavioral traits. Various immune anomalies, including humoral and cellular immunity along with abnormalities at the molecular level, have been reported. There is evidence of altered immune function both in cerebrospinal fluid and peripheral blood. Several studies hypothesize a role for neuroinflammation in ASD and are supported by brain tissue and cerebrospinal fluid analysis, as well as evidence of microglial activation. It has been shown that immune abnormalities occur in a substantial number of individuals with ASD. Identifying subgroups with immune system dysregulation and linking specific cellular immunophenotypes to different symptoms would be key to defining a group of patients with immune abnormalities as a major etiology underlying behavioral symptoms. These determinations would provide the opportunity to investigate causative treatments for a defined patient group that may specifically benefit from such an approach. This review summarizes recent insights into immune system dysfunction in individuals with ASD and discusses the potential implications for future therapies.

Investigation of epigenetic regulatory networks associated with autism spectrum disorder (ASD) by integrated global LINE-1 methylation and gene expression profiling analyses

BACKGROUND

The exact cause and mechanisms underlying the pathobiology of autism spectrum disorder (ASD) remain unclear. Dysregulation of long interspersed element-1 (LINE-1) has been reported in the brains of ASD-like mutant mice and ASD brain tissues. However, the role and methylation of LINE-1 in individuals with ASD remain unclear. In this study, we aimed to investigate whether LINE-1 insertion is associated with differentially expressed genes (DEGs) and to assess LINE-1 methylation in ASD.

METHODS

To identify DEGs associated with LINE-1 in ASD, we reanalyzed previously published transcriptome profiles and overlapped them with the list of LINE-1-containing genes from the TranspoGene database. An Ingenuity Pathway Analysis (IPA) of DEGs associated with LINE-1 insertion was conducted. DNA methylation of LINE-1 was assessed via combined bisulfite restriction analysis (COBRA) of lymphoblastoid cell lines from ASD individuals and unaffected individuals, and the methylation levels were correlated with the expression levels of LINE-1 and two LINE-1-inserted DEGs, C1orf27 and ARMC8.

RESULTS

We found that LINE-1 insertion was significantly associated with DEGs in ASD. The IPA showed that LINE-1-inserted DEGs were associated with ASD-related mechanisms, including sex hormone receptor signaling and axon guidance signaling. Moreover, we observed that the LINE-1 methylation level was significantly reduced in lymphoblastoid cell lines from ASD individuals with severe language impairment and was inversely correlated with the transcript level. The methylation level of LINE-1 was also correlated with the expression of the LINE-1-inserted DEG C1orf27 but not ARMC8.

CONCLUSIONS

In ASD individuals with severe language impairment, LINE-1 methylation was reduced and correlated with the expression levels of LINE-1 and the LINE-1-inserted DEG C1orf27. Our findings highlight the association of LINE-1 with DEGs in ASD blood samples and warrant further investigation. The molecular mechanisms of LINE-1 and the effects of its methylation in ASD pathobiology deserve further study.

Metabolism-Associated Markers and Childhood Autism Rating Scales (CARS) as a Measure of Autism Severity

Autism spectrum disorder (ASD) is a neuro-behavioral syndrome with a broad spectrum of different mechanisms and etiologies that are caused by abnormal brain development. To date, no highly reliable and effective diagnostic biomarker to assess ASD is available so far. The present study investigated the predictivity potential of some suggested markers in ASD diagnosis focusing onto the relative ratios of several plasma biomarkers of electron transport chain function, and mitochondrial metabolism in 41 patients with ASD evaluated for behavior deficits measured using Childhood Autism Rating Scales (CARS). The control matched for further 41 healthy subjects. The relation of these relative ratios to ASD severity was also examined, as well as their ability to distinguish ASD children from neurotypical children. All predictive ratios were found to be markedly altered and correlated in ASD patients. However, no ratio was connected with autism severity. Interestingly, MRCC-I/caspase-7, GSH/GST, and MRCC-I/COQ10 were the most distinctive relative ratios between neurotypical controls and ASD patients and may thereby be useful biomarkers for early diagnosis of ASD. Overall, this investigation proves that relative ratios of numerous mitochondrial biomarkers might be predictive and efficient to differentiate between neurotypical children and ASD.

Inflammation and Neuro-Immune Dysregulations in Autism Spectrum Disorders

Autism Spectrum Disorder (ASD) is characterized by persistent deficits in social communication and interaction and restricted-repetitive patterns of behavior, interests, or activities. Strong inflammation states are associated with ASD. This inflammatory condition is often linked to immune system dysfunction. Several cell types are enrolled to trigger and sustain these processes. Neuro-inflammation and neuro-immune abnormalities have now been established in ASD as key factors in its development and maintenance. In this review, we will explore inflammatory conditions, dysfunctions in neuro-immune cross-talk, and immune system treatments in ASD management.

In the search for reliable biomarkers for the early diagnosis of autism spectrum disorder: the role of vitamin D

Autism spectrum disorder (ASD) affects about 1% of the world's population. Vitamin D is thought to be essential for normal brain development and modulation of the immune system. Worldwide about 1 billion people are affected by vitamin D deficiency. High-sensitivity C-reactive protein (hs-CRP), cytochrome P450 2E1 (CYP2E1) and 8-hydroxy-2'-deoxyguanosine (8-OH-dG) are biomarkers related to inflammation and oxidative stress. In the present study, these biomarkers were together with serum 25-hydroxyvitamin D (25(OH)D₃) analyzed in 28 (mean age seven years) Saudi male patients with ASD. The study was conducted to determine if there is any relationship between vitamin D levels, the tested biomarkers and the presence and severity of ASD. The hope was to identify if these biomarkers may be useful for early ASD diagnosis. The Childhood Autism Rating Scale (CARS) and the Social Responsiveness Scale (SRS) were used to measure autism severity. The results of the ASD children were compared with 27 age and gender-matched neurotypical controls. The data indicated that Saudi patients with ASD have significantly lower plasma levels of 25(OH)D₃ than neurotypical controls (38 ng/ml compared to 56 ng/ml, respectively; [P = 0.001]). Surprisingly, the levels of CYP2E1 were lower in the children with ASD than the neurotypical controls (0.48 ± 0.08 vs. 69 ± 0.07 ng/ml, respectively; P = 0.001). The ASD children also had significantly higher levels of hs-CRP (0.79 ± 0.09 vs. 0.59 ± 0.09 ng/ml, respectively; P = 0.001) and 8-OH-dG (8.17 ± 1.04 vs. 4.13 ± 1.01 ng/ml, respectively; P = 0.001, compared to neurotypical age and gender-matched controls. The values for hs-CRP and 8-OH-dG did not correlate [P < 0.001] with autism severity. There was found a relationship between autism severity on the CARS scale and the levels of 25(OH)D₃ and CYP1B1. But this was not found for SRS. All four biomarkers seemed to have good sensitivity and specificity, but the sample size of the present study was too small to determine clinical usefulness. The findings also indicate that inadequate levels of vitamin D play a role in the etiology and severity of autism. Furthermore, the results of the present study suggest the possibility of using 25(OH)D₃, CYP1B1, hs-CRP and 8-OH-dG, preferably in combination, as biomarkers for the early diagnosis of ASD. However, further research is needed to evaluate this hypothesis.

Integrated genome-wide Alu methylation and transcriptome profiling analyses reveal novel epigenetic regulatory networks associated with autism spectrum disorder

Background

Alu elements are a group of repetitive elements that can influence gene expression through CpG residues and transcription factor binding. Altered gene expression and methylation profiles have been reported in various tissues and cell lines from individuals with autism spectrum disorder (ASD). However, the role of Alu elements in ASD remains unclear. We thus investigated whether Alu elements are associated with altered gene expression profiles in ASD.

Methods

We obtained five blood-based gene expression profiles from the Gene Expression Omnibus database and human Alu-inserted gene lists from the TranspoGene database. Differentially expressed genes (DEGs) in ASD were identified from each study and overlapped with the human Alu-inserted genes. The biological functions and networks of Alu-inserted DEGs were then predicted by Ingenuity Pathway Analysis (IPA). A combined bisulfite restriction analysis of lymphoblastoid cell lines (LCLs) derived from 36 ASD and 20 sex- and age-matched unaffected individuals was performed to assess the global DNA methylation levels within Alu elements, and the Alu expression levels were determined by quantitative RT-PCR.

Results

In ASD blood or blood-derived cells, 320 Alu-inserted genes were reproducibly differentially expressed. Biological function and pathway analysis showed that these genes were significantly associated with neurodevelopmental disorders and neurological functions involved in ASD etiology. Interestingly, estrogen receptor and androgen signaling pathways implicated in the sex bias of ASD, as well as IL-6 signaling and neuroinflammation signaling pathways, were also highlighted. Alu methylation was not significantly different between the ASD and sex- and age-matched control groups. However, significantly altered Alu methylation patterns were observed in ASD cases sub-grouped based on Autism Diagnostic Interview-Revised scores compared with matched controls. Quantitative RT-PCR analysis of Alu expression also showed significant differences between ASD subgroups. Interestingly, Alu expression was correlated with methylation status in one phenotypic ASD subgroup.

Conclusion

Alu methylation and expression were altered in LCLs from ASD subgroups. Our findings highlight the association of Alu elements with gene dysregulation in ASD blood samples and warrant further investigation. Moreover, the classification of ASD individuals into subgroups based on phenotypes may be beneficial and could provide insights into the still unknown etiology and the underlying mechanisms of ASD.

Electronic supplementary material

The online version of this article (10.1186/s13229-018-0213-9) contains supplementary material, which is available to authorized users.

Interplay Between Peripheral and Central Inflammation in Autism Spectrum Disorders: Possible Nutritional and Therapeutic Strategies

Pre- and post-natal factors can affect brain development and function, impacting health outcomes with particular relevance to neurodevelopmental diseases, such as autism spectrum disorders (ASDs). Maternal obesity and its associated complications have been related to the increased risk of ASDs in offspring. Indeed, animals exposed to maternal obesity or high fat diets are prone to social communication impairment and repetitive behavior, the hallmarks of autism. During development, fatty acids and sugars, as well as satiety hormones, like insulin and leptin, and inflammatory factors related to obesity-induced low grade inflammation, could play a role in the impairment of neuroendocrine system and brain neuronal circuits regulating behavior in offspring. On the other side, post-natal factors, such as mode of delivery, stress, diet, or antibiotic treatment are associated to a modification of gut microbiota composition, perturbing microbiota-gut-brain axis. Indeed, the interplay between the gastrointestinal tract and the central nervous system not only occurs through neural, hormonal, and immune pathways, but also through microbe-derived metabolic products. The modification of unhealthy perinatal and postnatal environment, manipulation of gut microbiota, nutritional, and dietary interventions could represent possible strategies in preventing or limiting ASDs, through targeting inflammatory process and gut microbiota.

Children With Autism Spectrum Disorder With Regression Exhibit a Different Profile in Plasma Cytokines and Adhesion Molecules Compared to Children Without Such Regression

Background: In the etiopathogenesis of autism spectrum disorder (ASD), it has been suggested that a proinflammatory condition, as well as an alteration in adhesion molecules in the early stages of neurodevelopment, may play a role in the pathophysiology of the disorder. This study set out to evaluate the plasma levels of certain inflammatory cytokines, adhesion molecules, and growth factors in a sample of pediatric patients with ASD and compare them to the levels in a control group of healthy children. Methods: Fifty-four children (45 males and nine females) aged 2-6, who were diagnosed with ASD, and a control group of 54 typically-developing children of similar ages were selected. The diagnosis of ASD was carried out in accordance with the DSM-5 criteria and the data obtained from a developmental semi-structured clinical interview and the ADOS evaluation test. Additional testing was carried out to identify the children's developmental level and severity of ASD symptomatology. Patients with ASD were further divided into two subgroups based on developmental parameters: ASD children with neurodevelopmental regression (AMR) and ASD children without neurodevelopmental regression (ANMR). Analyses of plasma molecules, such as cathepsin, IL1β, IL6, IL8, MPO, RANTES, MCP, BDNF, PAI NCAM, sICAM, sVCAM and NGF, were performed. Results: Higher levels of NGF were observed in the ASD group compared with the levels in the control group (p < 0.05). However, in the analysis of the ASD subgroups, lower plasma levels of NCAM and higher levels of NGF were found in the group of ASD children without developmental regression compared to the levels in the group of typically-developing children. Conclusions: These results suggest differences that could be related to different pathophysiological mechanisms in ASD. There is not a specific profile for the expression of relevant plasma cytokines, adhesion molecules or growth factors in children with ASD compared with that in typically-developing children. However, in the ANMR and AMR subgroups, some of the adhesion molecules and neuronal growth factors show differences that may be related to synaptogenesis.

Developmental Neurotoxicity of Traffic-Related Air Pollution: Focus on Autism

PURPOSE OF REVIEW

Epidemiological and animal studies suggest that air pollution may negatively affect the central nervous system (CNS) and contribute to CNS diseases. Traffic-related air pollution is a major contributor to global air pollution, and diesel exhaust (DE) is its most important component.

RECENT FINDINGS

Several studies suggest that young individuals may be particularly susceptible to air pollution-induced neurotoxicity and that perinatal exposure may cause or contribute to developmental disabilities and behavioral abnormalities. In particular, a number of recent studies have found associations between exposures to traffic-related air pollution and autism spectrum disorders (ASD), which are characterized by impairment in socialization and in communication and by the presence of repetitive and unusual behaviors. The cause(s) of ASD are unknown, and while it may have a hereditary component, environmental factors are increasingly suspected as playing a pivotal role in its etiology, particularly in genetically susceptible individuals. Autistic children present higher levels of neuroinflammation and systemic inflammation, which are also hallmarks of exposure to traffic-related air pollution. Gene-environment interactions may play a relevant role in determining individual susceptibility to air pollution developmental neurotoxicity. Given the worldwide presence of elevated air pollution, studies on its effects and mechanisms on the developing brain, genetic susceptibility, role in neurodevelopmental disorders, and possible therapeutic interventions are certainly warranted.

Neurotoxicity of traffic-related air pollution

The central nervous system is emerging as an important target for adverse health effects of air pollution, where it may contribute to neurodevelopmental and neurodegenerative disorders. Air pollution comprises several components, including particulate matter (PM) and ultrafine particulate matter (UFPM), gases, organic compounds, and metals. An important source of ambient PM and UFPM is represented by traffic-related air pollution, primarily diesel exhaust (DE). Human epidemiological studies and controlled animal studies have shown that exposure to air pollution, and to traffic-related air pollution or DE in particular, may lead to neurotoxicity. In particular, air pollution is emerging as a possible etiological factor in neurodevelopmental (e.g. autism spectrum disorders) and neurodegenerative (e.g. Alzheimer's disease) disorders. The most prominent effects caused by air pollution in both humans and animals are oxidative stress and neuro-inflammation. Studies in mice acutely exposed to DE (250-300μg/m3 for 6h) have shown microglia activation, increased lipid peroxidation, and neuro-inflammation in various brain regions, particularly the hippocampus and the olfactory bulb. An impairment of adult neurogenesis was also found. In most cases, the effects of DE were more pronounced in male mice, possibly because of lower antioxidant abilities due to lower expression of paraoxonase 2.

Elevated plasma concentrations of S100 calcium-binding protein B and tumor necrosis factor alpha in children with autism spectrum disorders

Objective:

To investigate plasma concentrations of S100B (a calcium-binding protein derived primarily from the glia) and inflammatory cytokines in children with autism and the relationship between S100B and cytokine concentrations.

Methods:

Plasma levels of S100B, tumor necrosis factor alpha (TNF-α), interferon gamma, interleukin (IL)-1β, IL-4, IL-6, IL-10, and IL-17A were measured in 40 unmedicated children with autism and 35 normally developing healthy children. The severity of autism was assessed using the Childhood Autism Rating Scale (CARS).

Results:

Concentrations of both S100B and TNF-α were higher in children with autism before and after adjusting for a priori-selected confounders (age, sex, and body mass index). S100B concentrations were higher in children with severe autism compared to children with mild-moderate autism. However, this association remained as a trend after adjusting for confounders. S100B concentrations correlated positively with TNF-α concentrations.

Conclusion:

Our findings showing an increase in peripheral concentrations of S100B and TNF-α provide limited support to the hypothesis about the roles of altered immune function and S100B in autism spectrum disorder (ASD). Studies of larger numbers of well-characterized individuals with ASD are needed to clarify the potential role of the immune system in the pathophysiology of this disorder.

Sex and genetic differences in the effects of acute diesel exhaust exposure on inflammation and oxidative stress in mouse brain

In addition to increased morbidity and mortality caused by respiratory and cardiovascular diseases, air pollution may also contribute to central nervous system (CNS) diseases. Traffic-related air pollution is a major contributor to global air pollution, and diesel exhaust (DE) is its most important component. DE contains more than 40 toxic air pollutants and is a major constituent of ambient particulate matter (PM), particularly of ultrafine-PM. Limited information suggests that exposure to DE may cause oxidative stress and neuroinflammation in the CNS. We hypothesized that males may be more susceptible than females to DE neurotoxicity, because of a lower level of expression of paraoxonase 2 (PON2), an intracellular anti-oxidant and anti-inflammatory enzyme. Acute exposure of C57BL/6 mice to DE (250-300μg/m3 for 6h) caused significant increases in lipid peroxidation and of pro-inflammatory cytokines (IL-1α, IL-1β, IL-3, IL-6, TNF-α) in various brain regions (particularly olfactory bulb and hippocampus). In a number of cases the observed effects were more pronounced in male than in female mice. DE exposure also caused microglia activation, as measured by increased Iba1 (ionized calcium-binding adapter molecule 1) expression, and of TSPO (translocator protein) binding. Mice heterozygotes for the modifier subunit of glutamate cysteine ligase (the limiting enzyme in glutathione biosynthesis; Gclm+/- mice) appeared to be significantly more susceptible to DE-induced neuroinflammation than wild type mice. These findings indicate that acute exposure to DE causes neuroinflammation and oxidative stress in brain, and suggest that sex and genetic background may play important roles in modulating susceptibility to DE neurotoxicity.

Common Genetic Variants Found in HLA and KIR Immune Genes in Autism Spectrum Disorder

The "common variant-common disease" hypothesis was proposed to explain diseases with strong inheritance. This model suggests that a genetic disease is the result of the combination of several common genetic variants. Common genetic variants are described as a 5% frequency differential between diseased vs. matched control populations. This theory was recently supported by an epidemiology paper stating that about 50% of genetic risk for autism resides in common variants. However, rare variants, rather than common variants, have been found in numerous genome wide genetic studies and many have concluded that the "common variant-common disease" hypothesis is incorrect. One interpretation is that rare variants are major contributors to genetic diseases and autism involves the interaction of many rare variants, especially in the brain. It is obvious there is much yet to be learned about autism genetics. Evidence has been mounting over the years indicating immune involvement in autism, particularly the HLA genes on chromosome 6 and KIR genes on chromosome 19. These two large multigene complexes have important immune functions and have been shown to interact to eliminate unwanted virally infected and malignant cells. HLA proteins have important functions in antigen presentation in adaptive immunity and specific epitopes on HLA class I proteins act as cognate ligands for KIR receptors in innate immunity. Data suggests that HLA alleles and KIR activating genes/haplotypes are common variants in different autism populations. For example, class I allele (HLA-A2 and HLA-G 14 bp-indel) frequencies are significantly increased by more than 5% over control populations (Table 2). The HLA-DR4 Class II and shared epitope frequencies are significantly above the control populations (Table 2). Three activating KIR genes: 3DS1, 2DS1, and 2DS2 have increased frequencies of 15, 22, and 14% in autism populations, respectively. There is a 6% increase in total activating KIR genes in autism over control subjects. And, more importantly there is a 12% increase in activating KIR genes and their cognate HLA alleles over control populations (Torres et al., 2012a). These data suggest the interaction of HLA ligand/KIR receptor pairs encoded on two different chromosomes is more significant as a ligand/receptor complex than separately in autism.

Hyperbaric oxygen therapy for people with autism spectrum disorder (ASD)

BACKGROUND

The rising prevalence of autism spectrum disorder (ASD) has increased the need for evidence-based treatments to lessen the impact of symptoms. Presently, no therapies are available to effectively treat individuals with all of the symptoms of this disorder. It has been suggested that hyperbaric oxygen therapy may alleviate the biochemical dysfunction and clinical symptoms of ASD.

OBJECTIVES

To determine whether treatment with hyperbaric oxygen:1. improves core symptoms of ASD, including social communication problems and stereotypical and repetitive behaviors;2. improves noncore symptoms of ASD, such as challenging behaviors;3. improves comorbid states, such as depression and anxiety; and4. causes adverse effects.

SEARCH METHODS

On 10 December 2015, we searched CENTRAL, Ovid MEDLINE, Embase, and 15 other databases, four of which were Chinese language databases. We also searched multiple trial and research registers.

SELECTION CRITERIA

We selected randomized controlled trials (RCTs) and quasi-RCTs of any dose, duration, and frequency for hyperbaric oxygen therapy compared with no treatment or sham treatment for children and adults with ASD.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by The Cochrane Collaboration, in that three review authors independently selected studies, assessed them for risk of bias, and extracted relevant data. We also assessed the quality of the evidence by using the GRADE approach.

MAIN RESULTS

We included one trial with a total of 60 children with a diagnosis of ASD who randomly received hyperbaric oxygen therapy or a sham treatment. Using GRADE criteria, we rated the quality of the evidence as low because of the small sample size and wide confidence intervals (CIs). Other problems included selection bias and short duration or follow-up.Overall, study authors reported no improvement in social interaction and communication, behavioral problems, communication and linguistic abilities, or cognitive function. With regard to the safety of hyperbaric oxygen therapy (adverse events), they reported minor-grade ear barotrauma events. Investigators found significant differences between groups in total number of side effect events (Peto odds ratio (OR) 3.87, 95% CI 1.53 to 9.82) and in the number of children who experienced side effects (Peto OR 4.40, 95% CI 1.33 to 14.48).

AUTHORS' CONCLUSIONS

To date, there is no evidence that hyperbaric oxygen therapy improves core symptoms and associated symptoms of ASD. It is important to note that adverse effects (minor-grade ear barotrauma events) can occur. Given the absence of evidence of effectiveness and the limited biological plausibility and possible adverse effects, the need for future RCTs of hyperbaric oxygen therapy must be carefully considered.

Beneficial Effects of Co-Ultramicronized Palmitoylethanolamide/Luteolin in a Mouse Model of Autism and in a Case Report of Autism

AIMS

Autism spectrum disorder (ASD) is a condition defined by social communication deficits and repetitive restrictive behaviors. Association of the fatty acid amide palmitoylethanolamide (PEA) with the flavonoid luteolin displays neuroprotective and antiinflammatory actions in different models of central nervous system pathologies. We hypothesized that association of PEA with luteolin might have therapeutic utility in ASD, and we employed a well-recognized autism animal model, namely sodium valproate administration, to evaluate cognitive and motor deficits.

METHODS

Two sets of experiments were conducted. In the first, we investigated the effect of association of ultramicronized PEA with luteolin, co-ultramicronized PEA-LUT® (co-ultraPEA-LUT®) in a murine model of autistic behaviors, while in the second, the effect of co-ultraPEA-LUT® in a patient affected by ASD was examined.

RESULTS

Co-ultraPEA-LUT® treatment ameliorated social and nonsocial behaviors in valproic acid-induced autistic mice and improved clinical picture with reduction in stereotypes in a 10-year-old male child.

CONCLUSION

These data suggest that ASD symptomatology may be improved by agents documented to control activation of mast cells and microglia. Co-ultraPEA-LUT® might be a valid and safe therapy for the symptoms of ASD alone or in combination with other used drugs.

Genetic and epigenetic methylation defects and implication of the ERMN gene in autism spectrum disorders

Autism spectrum disorders (ASD) are highly heritable and genetically complex conditions. Although highly penetrant mutations in multiple genes have been identified, they account for the etiology of <1/3 of cases. There is also strong evidence for environmental contribution to ASD, which can be mediated by still poorly explored epigenetic modifications. We searched for methylation changes on blood DNA of 53 male ASD patients and 757 healthy controls using a methylomic array (450K Illumina), correlated the variants with transcriptional alterations in blood RNAseq data, and performed a case-control association study of the relevant findings in a larger cohort (394 cases and 500 controls). We found 700 differentially methylated CpGs, most of them hypomethylated in the ASD group (83.9%), with cis-acting expression changes at 7.6% of locations. Relevant findings included: (1) hypomethylation caused by rare genetic variants (meSNVs) at six loci (ERMN, USP24, METTL21C, PDE10A, STX16 and DBT) significantly associated with ASD (q-value <0.05); and (2) clustered epimutations associated to transcriptional changes in single-ASD patients (n=4). All meSNVs and clustered epimutations were inherited from unaffected parents. Resequencing of the top candidate genes also revealed a significant load of deleterious mutations affecting ERMN in ASD compared with controls. Our data indicate that inherited methylation alterations detectable in blood DNA, due to either genetic or epigenetic defects, can affect gene expression and contribute to ASD susceptibility most likely in an additive manner, and implicate ERMN as a novel ASD gene.

Metabolomics of autism spectrum disorders: early insights regarding mammalian-microbial cometabolites

INTRODUCTION

Autism spectrum disorders (ASD) are a group of neurodevelopmental disorders consisting of delayed or impaired language development and difficulties in social interactions. The very high degree of phenotypic heterogeneity in ASD originates from the interaction between environmental risk factors and susceptible genetic loci, leading to epigenetic DNA methylation. Advances in system biology are becoming strategic for implementing knowledge on the ASD aetiology and for the early diagnosis of the disease after birth.

AREAS COVERED

We overhauled the value of either targeted or untargeted metabolomics studies in autism for identifying the most relevant metabolic pathways and key metabolites implicated in the disease, with special emphasis to mammalian-microbial metabolites. The most discriminant metabolites in ASD belong to amino acid metabolism, antioxidant status, nicotinic acid metabolism, and mitochondrial metabolism. Expert commentary: Most published studies point out the role of metabolites derived from the gut microbiota: they can modulate the behavioral phenotype of the autistic children, greatly influencing host metabolic pathways and the immune system, shaping the individual susceptibility to the disease. Pitfalls and caveats in metabolomics results across studies have been additionally recognized and discussed leading to the conclusion that metabolomics studies in ASD are far to be definitive and univocal.

Therapeutic potency of bee pollen against biochemical autistic features induced through acute and sub-acute neurotoxicity of orally administered propionic acid

Background

It is now well documented that postnatal exposure to certain chemicals has been reported to increase the risk of autism spectrum disorder. Propionic acid (PA), as a metabolic product of gut microbiotaandas a commonly used food additive, has been reported to mediate the effects of autism. Results from animal studies may help to identify environmental neurotoxic agents and drugs that can ameliorate neurotoxicity and may thereby aid in the treatment of autism. The present study investigated the ameliorative effects of natural bee pollen against acute and sub-acute brain intoxication induced by (PA) in rats.

Methods

Twenty-four young male Western Albino ratswere enrolled in the present study. They were classified into four equal groups, eachwith6 rats. The control group received only phosphate buffered saline; the oral buffered PA-treated groups (II and III) received a neurotoxic dose of 750 mg/kg body weight divided in 3 dose of 250 mg/kg body weight/day serving asthe acute group and 750 mg/kg body weight divided in 10 equal dose of 75 mg/kg body weight/day as the sub-acute group. The fourth group received 50 mg bee pollen for 30 days after PA-acute intoxication.

Results

The obtained data showed that the PA-treated groups demonstrated multiple signs of brain toxicity, as indicated by a depletion of serotonin (5HT), dopamine and nor-adrenaline, together withan increase in IFN-γ and caspase 3. Bee pollen was effective in ameliorating the neurotoxic effect of PA. All measured parameters demonstrated minimal alteration in comparison with thecontrol animal than did those of acute and sub-acute PA-treated animals.

Conclusions

In conclusion, bee pollen demonstrates anti-inflammatory and anti-apoptotic effects while ameliorating the impaired neurochemistry of PA-intoxicated rats.

Developmental neurotoxicity of inhaled ambient ultrafine particle air pollution: Parallels with neuropathological and behavioral features of autism and other neurodevelopmental disorders

Accumulating evidence from both human and animal studies show that brain is a target of air pollution. Multiple epidemiological studies have now linked components of air pollution to diagnosis of autism spectrum disorder (ASD), a linkage with plausibility based on the shared mechanisms of inflammation. Additional plausibility appears to be provided by findings from our studies in mice of exposures from postnatal day (PND) 4-7 and 10-13 (human 3rd trimester equivalent), to concentrated ambient ultrafine (UFP) particles, considered the most reactive component of air pollution, at levels consistent with high traffic areas of major U.S. cities and thus highly relevant to human exposures. These exposures, occurring during a period of marked neuro- and gliogenesis, unexpectedly produced a pattern of developmental neurotoxicity notably similar to multiple hypothesized mechanistic underpinnings of ASD, including its greater impact in males. UFP exposures induced inflammation/microglial activation, reductions in size of the corpus callosum (CC) and associated hypomyelination, aberrant white matter development and/or structural integrity with ventriculomegaly (VM), elevated glutamate and excitatory/inhibitory imbalance, increased amygdala astrocytic activation, and repetitive and impulsive behaviors. Collectively, these findings suggest the human 3rd trimester equivalent as a period of potential vulnerability to neurodevelopmental toxicity to UFP, particularly in males, and point to the possibility that UFP air pollution exposure during periods of rapid neuro- and gliogenesis may be a risk factor not only for ASD, but also for other neurodevelopmental disorders that share features with ASD, such as schizophrenia, attention deficit disorder, and periventricular leukomalacia.

Perspective Biological Markers for Autism Spectrum Disorders: Advantages of the Use of Receiver Operating Characteristic Curves in Evaluating Marker Sensitivity and Specificity

Autism Spectrum Disorders (ASD) are a heterogeneous group of neurodevelopmental disorders. Recognized causes of ASD include genetic factors, metabolic diseases, toxic and environmental factors, and a combination of these. Available tests fail to recognize genetic abnormalities in about 70% of ASD children, where diagnosis is solely based on behavioral signs and symptoms, which are difficult to evaluate in very young children. Although it is advisable that specific psychotherapeutic and pedagogic interventions are initiated as early as possible, early diagnosis is hampered by the lack of nongenetic specific biological markers. In the past ten years, the scientific literature has reported dozens of neurophysiological and biochemical alterations in ASD children; however no real biomarker has emerged. Such literature is here reviewed in the light of Receiver Operating Characteristic (ROC) analysis, a very valuable statistical tool, which evaluates the sensitivity and the specificity of biomarkers to be used in diagnostic decision making. We also apply ROC analysis to some of our previously published data and discuss the increased diagnostic value of combining more variables in one ROC curve analysis. We also discuss the use of biomarkers as a tool for advancing our understanding of nonsyndromic ASD.

Luteolin as an anti-inflammatory and neuroprotective agent: A brief review

According to the World Health Organization, two billion people will be aged 60 years or older by 2050. Aging is a major risk factor for a number of neurodegenerative disorders. These age-related disorders currently represent one of the most important and challenging health problems worldwide. Therefore, much attention has been directed towards the design and development of neuroprotective agents derived from natural sources. These phytochemicals have demonstrated high efficacy and low adverse effects in multiple in vitro and in vivo studies. Among these phytochemicals, dietary flavonoids are an important and common chemical class of bioactive products, found in several fruits and vegetables. Luteolin is an important flavone, which is found in several plant products, including broccoli, pepper, thyme, and celery. Numerous studies have shown that luteolin possesses beneficial neuroprotective effects both in vitro and in vivo. Despite this, an overview of the neuroprotective effects of luteolin has not yet been accomplished. Therefore, the aim of this paper is to provide a review of the available literature regarding the neuroprotective effects of luteolin and its molecular mechanisms of action. Herein, we also review the available literature regarding the chemistry of luteolin, its herbal sources, and bioavailability as a pharmacological agent for the treatment and management of age-related neurodegenerative disorders.

Autistic children exhibit decreased levels of essential Fatty acids in red blood cells

Omega-6 (n-6) and omega-3 (n-3) polyunsaturated fatty acids (PUFA) are essential nutrients for brain development and function. However, whether or not the levels of these fatty acids are altered in individuals with autism remains debatable. In this study, we compared the fatty acid contents between 121 autistic patients and 110 non-autistic, non-developmentally delayed controls, aged 3–17. Analysis of the fatty acid composition of red blood cell (RBC) membrane phospholipids showed that the percentage of total PUFA was lower in autistic patients than in controls; levels of n-6 arachidonic acid (AA) and n-3 docosahexaenoic acid (DHA) were particularly decreased (p < 0.001). In addition, plasma levels of the pro-inflammatory AA metabolite prostaglandin E2 (PGE2) were higher in a subset of the autistic participants (n = 20) compared to controls. Our study demonstrates an alteration in the PUFA profile and increased production of a PUFA-derived metabolite in autistic patients, supporting the hypothesis that abnormal lipid metabolism is implicated in autism.

Autism and our intestinal microbiota

Microbial products, released into the bloodstreams of mammals including humans, cross the blood-brain barrier and influence neurodevelopment. They can either promote or alleviate neurological disorders including autism spectrum disorders (ASD). This editorial describes how our microbiota influence our feelings, attitudes and mental states with particular reference to ASD.

Amyotrophic lateral sclerosis: a long preclinical period?

The onset of amyotrophic lateral sclerosis (ALS) is conventionally considered as commencing with the recognition of clinical symptoms. We propose that, in common with other neurodegenerations, the pathogenic mechanisms culminating in ALS phenotypes begin much earlier in life. Animal models of genetically determined ALS exhibit pathological abnormalities long predating clinical deficits. The overt clinical ALS phenotype may develop when safety margins are exceeded subsequent to years of mitochondrial dysfunction, neuroinflammation or an imbalanced environment of excitation and inhibition in the neuropil. Somatic mutations, the epigenome and external environmental influences may interact to trigger a metabolic cascade that in the adult eventually exceeds functional threshold. A long preclinical and subsequent presymptomatic period pose a challenge for recognition, since it offers an opportunity for protective and perhaps even preventive therapeutic intervention to rescue dysfunctional neurons. We suggest, by analogy with other neurodegenerations and from SOD1 ALS mouse studies, that vulnerability might be induced in the perinatal period.

Mesenchymal stem cells in treating autism: Novel insights

Autism spectrum disorders (ASDs) are complex neurodevelopmental disorders characterized by dysfunctions in social interactions, abnormal to absent verbal communication, restricted interests, and repetitive stereotypic verbal and non-verbal behaviors, influencing the ability to relate to and communicate. The core symptoms of ASDs concern the cognitive, emotional, and neurobehavioural domains. The prevalence of autism appears to be increasing at an alarming rate, yet there is a lack of effective and definitive pharmacological options. This has created an increased sense of urgency, and the need to identify novel therapies. Given the growing awareness of immune dysregulation in a significant portion of the autistic population, cell therapies have been proposed and applied to ASDs. In particular, mesenchymal stem cells (MSCs) possess the immunological properties which make them promising candidates in regenerative medicine. MSC therapy may be applicable to several diseases associated with inflammation and tissue damage, where subsequent regeneration and repair is necessary. MSCs could exert a positive effect in ASDs through the following mechanisms: stimulation of repair in the damaged tissue, e.g., inflammatory bowel disease; synthesizing and releasing anti-inflammatory cytokines and survival-promoting growth factors; integrating into existing neural and synaptic network, and restoring plasticity. The paracrine mechanisms of MSCs show interesting potential in ASD treatment. Promising and impressive results have been reported from the few clinical studies published to date, although the exact mechanisms of action of MSCs in ASDs to restore functions are still largely unknown. The potential role of MSCs in mediating ASD recovery is discussed in light of the newest findings from recent clinical studies.

Heat shock alters the expression of schizophrenia and autism candidate genes in an induced pluripotent stem cell model of the human telencephalon

Schizophrenia (SZ) and autism spectrum disorders (ASD) are highly heritable neuropsychiatric disorders, although environmental factors, such as maternal immune activation (MIA), play a role as well. Cytokines mediate the effects of MIA on neurogenesis and behavior in animal models. However, MIA stimulators can also induce a febrile reaction, which could have independent effects on neurogenesis through heat shock (HS)-regulated cellular stress pathways. However, this has not been well-studied. To help understand the role of fever in MIA, we used a recently described model of human brain development in which induced pluripotent stem cells (iPSCs) differentiate into 3-dimensional neuronal aggregates that resemble a first trimester telencephalon. RNA-seq was carried out on aggregates that were heat shocked at 39°C for 24 hours, along with their control partners maintained at 37°C. 186 genes showed significant differences in expression following HS (p<0.05), including known HS-inducible genes, as expected, as well as those coding for NGFR and a number of SZ and ASD candidates, including SMARCA2, DPP10, ARNT2, AHI1 and ZNF804A. The degree to which the expression of these genes decrease or increase during HS is similar to that found in copy loss and copy gain copy number variants (CNVs), although the effects of HS are likely to be transient. The dramatic effect on the expression of some SZ and ASD genes places HS, and perhaps other cellular stressors, into a common conceptual framework with disease-causing genetic variants. The findings also suggest that some candidate genes that are assumed to have a relatively limited impact on SZ and ASD pathogenesis based on a small number of positive genetic findings, such as SMARCA2 and ARNT2, may in fact have a much more substantial role in these disorders - as targets of common environmental stressors.

Serum antinucleosome-specific antibody as a marker of autoimmunity in children with autism

Background

Increasing evidence of autoimmune phenomena in some individuals with autism could represent the presence of altered or inappropriate immune responses in this disorder. The role of the nucleosome in the induction of antibody response in some autoimmune-mediated tissue damage may provide novel targets for treatment. Due to the paucity of studies investigating the frequency of systemic auto-antibodies in autism, we are the first to investigate the frequency of antinucleosome-specific antibodies in a group of autistic children.

Methods

Serum antinucleosome-specific antibodies were measured by ELISA in 60 autistic children, between the ages of 3 and 12 years, in comparison to 60 healthy children. Autistic severity was assessed using the Childhood Autism Rating Scale (CARS).

Results

Autistic children had significantly higher serum antinucleosome-specific antibodies than healthy children (P <0.001). The seropositivity of antinucleosome-specific antibodies was found in 46.7% of autistic children. Autistic children with a family history of autoimmunity (40%) had a significantly higher frequency of serum antinucleosome-specific antibodies (83.3%) than patients without such a history (22.2%, P <0.001).

Conclusions

Serum levels of antinucleosome-specific antibodies were increased in some autistic children. However, these data should be treated with caution until further investigations are performed with a larger subject population to determine whether these antibodies have a role in the induction of autoimmunity in a subgroup of autistic children. The role of immunotherapy in children with autism should be also studied.

Inflammation in children and adolescents with neuropsychiatric disorders: a systematic review

OBJECTIVE

There has been rapid growth in research regarding inflammation in neuropsychiatric disorders as it relates to youth. We therefore set out to systematically review the literature on inflammation and neuropsychiatric disorders in children and adolescents.

METHOD

A systematic review of the literature was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Studies were included if proinflammatory markers (PIMs) in children and/or adolescents with neuropsychiatric disorders were measured.

RESULTS

Sixty-seven studies were included, involving 3,952 youth. Evidence for a proinflammatory state is strongest for autism spectrum disorders (ASD). PIMs are elevated in children and adolescents with major depressive disorder (MDD), bipolar disorder (BD), post-traumatic stress disorder (PTSD), obsessive-compulsive disorder (OCD), Tourette's disorder (TD), attention-deficit/hyperactivity disorder (ADHD), and schizophrenia (SZ). However, the data are inconsistent. Evidence for specific PIMs is equivocal at this stage, although the findings in youth with MDD, BD, and PTSD converge with the extant adult literature in these areas. Definitive conclusions are limited by methodologic factors including cross-sectional and retrospective study design, between-study differences in specific markers and methods of analysis, small sample size, and other sources of heterogeneity.

CONCLUSION

The literature regarding inflammation among children and adolescents with neuropsychiatric disorders represents nearly 4,000 youth. There is preliminary evidence for elevated markers of inflammation in this population. Larger, prospective studies are needed to realize the goal of inflammatory markers informing clinical practice. In the interim, present findings suggest that further examination of this topic is warranted.

Neurotoxicants are in the air: convergence of human, animal, and in vitro studies on the effects of air pollution on the brain

In addition to increased morbidity and mortality caused by respiratory and cardiovascular diseases, air pollution may also negatively affect the brain and contribute to central nervous system diseases. Air pollution is a mixture comprised of several components, of which ultrafine particulate matter (UFPM; <100 nm) is of much concern, as these particles can enter the circulation and distribute to most organs, including the brain. A major constituent of ambient UFPM is represented by traffic-related air pollution, mostly ascribed to diesel exhaust (DE). Human epidemiological studies and controlled animal studies have shown that exposure to air pollution may lead to neurotoxicity. In addition to a variety of behavioral abnormalities, two prominent effects caused by air pollution are oxidative stress and neuroinflammation, which are seen in both humans and animals and are confirmed by in vitro studies. Among factors which can affect neurotoxic outcomes, age is considered the most relevant. Human and animal studies suggest that air pollution (and DE) may cause developmental neurotoxicity and may contribute to the etiology of neurodevelopmental disorders, including autistic spectrum disorders. In addition, air pollution exposure has been associated with increased expression of markers of neurodegenerative disease pathologies.

Association of social and cognitive impairment and biomarkers in autism spectrum disorders

Objectives

The neurological basis for autism is still not fully understood, and the role of the interaction between neuro-inflammation and neurotransmission impairment needs to be clearer. This study aims to test the possible association between impaired levels of gamma aminobutyric acid (GABA), serotonin, dopamine, oxytocin, and interferon-γ-induced protein-16 (IFI16) and the severity of social and cognitive dysfunctions in individuals with autism spectrum disorders.

Materials and methods

GABA, serotonin, dopamine, oxytocin, and IFI16 as biochemical parameters related to neurochemistry and inflammation were determined in the plasma of 52 Saudi autistic male patients, categorized as mild-moderate and severe as indicated by their Childhood Autism Rating Scale (CARS) or social responsiveness scale (SRS), and compared to 30 age- and gender-matched control samples.

Results

The data indicated that Saudi patients with autism have remarkably impaired plasma levels of the measured parameters compared to age and gender-matched controls. While serotonin in platelet-free plasma and dopamine did not correlated with the severity in social and cognitive dysfunction, GABA, oxytocin, and IFI16 were remarkably associated with the severity of both tested scores (SRS and CARS).

Conclusions

The relationship between the selected parameters confirms the role of impaired neurochemistry and neuro-inflammation in the etiology of autism spectrum disorders and the possibility of using GABA, oxytocin, and IFI16 as markers of autism severity. Receiver operating characteristic analysis together with predictiveness diagrams proved that the measured parameters could be used as predictive biomarkers of clinical symptoms and provide significant guidance for future therapeutic strategy to re-establish physiological homeostasis.

An open-label pilot study of a formulation containing the anti-inflammatory flavonoid luteolin and its effects on behavior in children with autism spectrum disorders

BACKGROUND

Accumulating evidence suggests an association between autism spectrum disorders (ASD) and inflammation in brain regions related to cognitive function. The natural flavonoid luteolin has antioxidant, anti-inflammatory, mast cell-blocking, and neuroprotective effects. It was shown to improve cognitive performance in a mouse model of ASD, but its effect in humans has not been adequately studied.

OBJECTIVES

The goal of this study was to assess the effectiveness and tolerability in white children with ASD of a dietary supplement containing 2 flavonoids (>95% pure), luteolin (100 mg/capsule, from chamomile) and quercetin (70 mg/capsule), and the quercetin glycoside rutin (30 mg/capsule) from the Sophora japonica leaf, formulated in olive kernel oil to increase oral absorption.

METHODS

Fifty children (4-10 years old; 42 boys and 8 girls) with ASD were enrolled in a 26-week, prospective, open-label trial at the 2nd University Department of Psychiatry at "Attikon" General Hospital, Athens, Greece. Children were referred for the study by their respective physicians or came from the practice of the senior author. ASD diagnosis by clinical assessment was based on the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision, symptom list and corroborated by using the Autism Diagnostic Observation Schedule. The dose of the study formulation used was 1 capsule per 10 kg weight per day with food. The primary outcome measures were the age-equivalent scores in the Vineland Adaptive Behavior Scales domains. Secondary outcomes included the Aberrant Behavior Checklist, the Autism Treatment Evaluation Checklist, and the Clinical Global Impression-Improvement score. Data were measured at baseline, week 18, and week 26. Parents were interviewed for any possible improvements they noticed and instructed to report any unusual adverse events.

RESULTS

A total of 40 children completed the protocol. There was a significant improvement in adaptive functioning as measured by using the VABS age-equivalent scores (8.43 months in the communication domain, 7.17 months in daily living skills, and 8 months in the social domain; P < 0.005), as well as in overall behavior as indicated by the reduction (26.6%-34.8%) in Aberrant Behavior Checklist subscale scores. Age, sex, and history of allergies had no effect on the results, whereas the initial level of functioning or difficulty did predict the final outcome in most of the measures used. There was a transient (1-8 weeks) increased irritability in 27 of the 50 participants.

CONCLUSIONS

These results are encouraging in that the combination of the flavonoids luteolin and quercetin seemed to be effective in reducing ASD symptoms, with no major adverse effects. ClinicalTrials.gov identifier: NCT01847521.

Autism and EMF? Plausibility of a pathophysiological link - Part I

Although autism spectrum conditions (ASCs) are defined behaviorally, they also involve multileveled disturbances of underlying biology that find striking parallels in the physiological impacts of electromagnetic frequency and radiofrequency exposures (EMF/RFR). Part I of this paper will review the critical contributions pathophysiology may make to the etiology, pathogenesis and ongoing generation of core features of ASCs. We will review pathophysiological damage to core cellular processes that are associated both with ASCs and with biological effects of EMF/RFR exposures that contribute to chronically disrupted homeostasis. Many studies of people with ASCs have identified oxidative stress and evidence of free radical damage, cellular stress proteins, and deficiencies of antioxidants such as glutathione. Elevated intracellular calcium in ASCs may be due to genetics or may be downstream of inflammation or environmental exposures. Cell membrane lipids may be peroxidized, mitochondria may be dysfunctional, and various kinds of immune system disturbances are common. Brain oxidative stress and inflammation as well as measures consistent with blood-brain barrier and brain perfusion compromise have been documented. Part II of this paper will review how behaviors in ASCs may emerge from alterations of electrophysiological oscillatory synchronization, how EMF/RFR could contribute to these by de-tuning the organism, and policy implications of these vulnerabilities. Changes in brain and autonomic nervous system electrophysiological function and sensory processing predominate, seizures are common, and sleep disruption is close to universal. All of these phenomena also occur with EMF/RFR exposure that can add to system overload ('allostatic load') in ASCs by increasing risk, and worsening challenging biological problems and symptoms; conversely, reducing exposure might ameliorate symptoms of ASCs by reducing obstruction of physiological repair. Various vital but vulnerable mechanisms such as calcium channels may be disrupted by environmental agents, various genes associated with autism or the interaction of both. With dramatic increases in reported ASCs that are coincident in time with the deployment of wireless technologies, we need aggressive investigation of potential ASC - EMF/RFR links. The evidence is sufficient to warrant new public exposure standards benchmarked to low-intensity (non-thermal) exposure levels now known to be biologically disruptive, and strong, interim precautionary practices are advocated.

Therapeutic role of hematopoietic stem cells in autism spectrum disorder-related inflammation

Autism and autism spectrum disorders (ASDs) are heterogeneous, severe neuro-developmental disorders with core symptoms of dysfunctions in social interactions and communication skills, restricted interests, repetitive – stereotypic verbal and non-verbal behaviors. Biomolecular evidence points to complex gene-environmental interactions in ASDs. Several biochemical processes are associated with ASDs: oxidative stress (including endoplasmic reticulum stress), decreased methylation capacity, limited production of glutathione; mitochondrial dysfunction, intestinal dysbiosis, increased toxic metal burden, and various immune abnormalities. The known immunological disorders include: T-lymphocyte populations and function, gene expression changes in monocytes, several autoimmune-related findings, high levels of N-acetylgalactosaminidase (which precludes macrophage activation), and primary immune deficiencies. These immunological observations may result in minicolumn structural changes in the brain, as well as, abnormal immune mediation of synaptic functions. Equally, these immune dysregulations serve as the rationale for immune-directed interventions such as hematopoietic stem cells (HSCs), which are pivotal in controlling chronic inflammation and in the restoration of immunological balance. These properties make them intriguing potential agents for ASD treatments. This prospective review will focus on the current state-of-the-art knowledge and challenges intrinsic in the application of HSCs for ASD-related immunological disorders.