Evaluation of oxidative stress in autism: defective antioxidant enzymes and increased lipid peroxidation

Determination of Nutrient Intake and Dietary Antioxidant Capacity in Autism Spectrum Disorder: A Case-Control Study

The aim of this study was to evaluate the nutrient intake and dietary antioxidant capacity of children and adolescents with ASD. The study included 38 children and adolescents with ASD aged 6-18 years and 38 gender and age-matched peers without ASD. Caregivers of participants who met inclusion criteria completed a questionnaire form, three-day food consumption record and antioxidant nutrient questionnaire. There were 26 (68.4%) boys and 12 (31.6%) girls in both groups and mean age of participants with and without ASD was 10.9 ± 4.03 years versus 11.1 ± 4.09 years, respectively. The average intake of carbohydrates, vitamin D, calcium, sodium and selenium was lower in participants with ASD than in participants without ASD (p < 0.05). In both groups, dietary fiber, vitamin D, potassium, calcium and selenium intake insufficiency were high, and there was a significant difference between the two groups in terms of carbohydrate, omega 3, vitamin D and sodium intake insufficiency. Considering the antioxidant intakes of the participants, the median value of dietary antioxidant capacity from food consumption record of participants with and without ASD was 3.2 (1.9) mmol versus 4.3 (1.9) mmol, respectively, whereas the dietary antioxidant capacity from antioxidant nutrient questionnaire was 3.5 (2.9) mmol versus 4.8 (2.7) mmol, respectively (p < 0.05). It is predicted that providing nutritional counseling and regulation of diet, especially keeping the antioxidant capacity of diets high, may be effective in reducing some of the symptoms of ASD.

Potential Neuroprotective Effect of Melatonin in the Hippocampus of Male BTBR Mice

Autism spectrum disorder (ASD) is a neurodevelopmental disorder identified by impairments in common social interactions and repetitive behaviors. In ASD patients, substantial morphological alterations have been observed in the hippocampus, which represents an important region for the development of social skills. Melatonin, commonly found in many foods and plants, is also produced by the pineal gland. This indolamine, known to regulate the circadian rhythm, shows antioxidant and anti-inflammatory properties. We therefore hypothesized that melatonin may reduce oxidative stress and inflammation in the hippocampus of ASD patients. We explored our hypothesis using the BTBR mouse, a well-regarded murine transgenic model for ASD. Immediately after weaning, male BTBR and C57BL/6 mice underwent an 8-week treatment with melatonin or vehicle. Later, through immunohistochemistry and the immunoblotting analysis of the hippocampus, we evaluated the overall expression and cellular localization of Nrf2 and SOD1, two enzymes involved in the oxidative stress response. Similarly, we evaluated NLRP3 and NFkB, two mediators of inflammation, and GAD67, an enzyme responsible for the synthesis of GABA. Ultimately, we addressed melatonin's potential to regulate iron metabolism through a DAB-enhanced Perls reaction assay. Results showed melatonin's potential for modulating the analyzed markers in BTBR mice, suggesting a potential neuroprotective effect in ASD patients.

Seeing beyond words: Visualizing autism spectrum disorder biomarker insights

Objective

This study employs bibliometric and visual analysis to elucidate global research trends in Autism Spectrum Disorder (ASD) biomarkers, identify critical research focal points, and discuss the potential integration of diverse biomarker modalities for precise ASD assessment.

Methods

A comprehensive bibliometric analysis was conducted using data from the Web of Science Core Collection database until December 31, 2022. Visualization tools, including R, VOSviewer, CiteSpace, and gCLUTO, were utilized to examine collaborative networks, co-citation patterns, and keyword associations among countries, institutions, authors, journals, documents, and keywords.

Results

ASD biomarker research emerged in 2004, accumulating a corpus of 4348 documents by December 31, 2022. The United States, with 1574 publications and an H-index of 213, emerged as the most prolific and influential country. The University of California, Davis, contributed significantly with 346 publications and an H-index of 69, making it the leading institution. Concerning journals, the Journal of Autism and Developmental Disorders, Autism Research, and PLOS ONE were the top three publishers of ASD biomarker-related articles among a total of 1140 academic journals. Co-citation and keyword analyses revealed research hotspots in genetics, imaging, oxidative stress, neuroinflammation, gut microbiota, and eye tracking. Emerging topics included "DNA methylation," "eye tracking," "metabolomics," and "resting-state fMRI."

Conclusion

The field of ASD biomarker research is dynamically evolving. Future endeavors should prioritize individual stratification, methodological standardization, the harmonious integration of biomarker modalities, and longitudinal studies to advance the precision of ASD diagnosis and treatment.

Impact of cow, buffalo, goat or camel milk consumption on oxidative stress, inflammation and immune response post weaning time

Milk is a whitish liquid that is secreted from mammary glands; and considered as the primary source of nutrition for newborns since they are not able to digest solid food. However, it contains primary nutrients, as well as growth and immune factors. Early weaning is a critical issue that face women and their babies in developing countries. To avoid infant malnutrition, they tend to use other milk types instead of baby formula. Therefore, the present study aimed to evaluate the impact of cow, buffalo, goat or camel milk consumption on oxidative stress, inflammation and immune response in male and female Sprague Dawley rats post weaning time. The amino acids, fatty acids, minerals and vitamins in the tested milk types were evaluated. Animals were divided into 5 groups (control, cow, buffalo, goat and camel milk administrated groups) (10 rats/group); each animal was administrated by 3.4 ml/day. Rats were administered with milk for 6 weeks; at the end of the 5th week, five animals of each group were isolated and the remaining five animals were immunized with sheep red blood cells (SRBCs) and kept for another week to mount immune response. The effect of different milk types on rats' immune response towards SRBCs was evaluated through pro-inflammatory cytokines, antioxidants, ESR and CRP measurement; together, with the histopathological examination of spleen samples and hemagglutination assay. Camel milk consumption reduced oxidative stress and inflammation in spleen that resulted from SRBCs immunization; in addition to, B cell stimulation that was apparent from the high level of anti-SRBCs antibodies. Camel milk is recommended for newborn consumption, due to its high-water content, unsaturated fatty acids, and vitamin C, as well as low lactose and fat content.

Sex-dependent alterations of inflammatory factors, oxidative stress, and histopathology of the brain-gut axis in a VPA-induced autistic-like model of rats

INTRODUCTION

In this study, we aimed to investigate the inflammatory factors, oxidative stress, and histopathological consequences of the brain-gut axis in male and female rats prenatally exposed to VPA.

METHODS

Pregnant Wistar rats were randomly divided into two groups. The animals received saline, and valproic acid (VPA) (600 mg/kg, i.p.) on embryonic day 12.5 (E12.5). All offspring were weaned on postnatal day 21, and the experiments were done in male and female rats on day 60. The brain and intestine tissues were extracted to assess histopathology, inflammation, and oxidative stress.

RESULTS

An increase of interleukin-1β (IL-1β) and interleukin-6 (IL-6) and a decrease of interleukin-10 (IL-10) were observed in the two sexes and two tissues of the autistic rats. In the VPA-exposed animals, malondialdehyde (MDA) and protein carbonyl (PC) increased in the brain of both sexes and the intestines of only the males. The total antioxidant capacity (TAC), superoxide dismutase (SOD), and catalase (CAT) significantly decreased in both tissues of male and female autistic groups. Histopathological evaluation showed that the %apoptosis of the cortex in the autistic male and female groups was more than in controls whereas this parameter in the CA1 and CA3 was significant only in the male rats. In the intestine, histopathologic changes were seen only in the male autistic animals.

CONCLUSION

The inflammatory and antioxidant factors were in line in the brain-gut axis in male and female rats prenatally exposed to VPA. Histopathological consequences were more significant in the VPA-exposed male animals.

Early-life exposure to PM2.5 leads to ASD-like phenotype in male offspring rats through activation of PI3K-AKT signaling pathway

Previous studies have shown that early-life exposure to fine particulate matter (PM2.5) is associated with an increasing risk of autism spectrum disorder (ASD), however, the specific sensitive period of ASD is unknown. Here, a model of dynamic whole-body concentrated PM2.5 exposure in pre- and early-postnatal male offspring rats (MORs) was established. And we found that early postnatal PM2.5 exposed rats showed more typical ASD behavioral characteristics than maternal pregnancy exposure rats, including poor social interaction, novelty avoidance and anxiety disorder. And more severe oxidative stress and inflammatory responses were observed in early postnatal PM2.5 exposed rats. Moreover, the expression level of phosphatase and tensin homolog deleted on chromosome ten (PTEN) was down-regulated and the ratios of p-PI3K/PI3K and p-AKT/AKT were up-regulated in early postnatal PM2.5 exposed rats. This study suggests that early postnatal exposure to PM2.5 is more susceptible to ASD-like phenotype in offspring than maternal pregnancy exposure and the activation of PI3K-AKT signaling pathway may represent underlying mechanisms.

Plant-mediated green synthesis of gold nanoparticles using an aqueous extract of Passiflora ligularis, optimization, characterizations, and their neuroprotective effect on propionic acid-induced autism in Wistar rats

The current study was conducted to examine an innovative method for synthesizing gold nanoparticles (AuNPs) from an aqueous sweet granadilla (Passiflora ligularis Juss) P. ligularis. Furthermore, the synthesized AuNPs were used to explore their potential neuroprotective impact against propionic acid (PPA)-induced autism. A sweet granadilla extract was used to achieve the synthesis of AuNPs. The structural and dimensional dispersion of AuNPs were confirmed by different techniques, including UV-Vis spectrophotometer (UV-Vis), X-ray Diffraction (XRD) Pattern, Energy Dispersive X-ray (EDX), Zeta potential, and High-Resolution Transmission Electron Microscopy (HRTEM) analysis. The AuNPs mediated by P. ligularis adopt a spherical shape morphology and the particle size was distributed in the range of 8.43-13 nm without aggregation. Moreover, in vivo, the anti-autistic effects of AuNPs administration were higher than those of P. ligularis extract per second. In addition, the reduced anxiety and neurobehavioral deficits of AuNPs were observed in autistic rats which halted the brain oxidative stress, reduced inflammatory cytokines, ameliorated neurotransmitters, and neurochemical release, and suppressed apoptotic genes (p < 0.05). The alleviated antiapoptotic gene expression and histopathological analysis confirmed that the treatment of AuNPs showed significant neural pathways that aid in reducing tissue damage and necrosis. The results emphasize that the biomedical activity was increased by using the green source synthesis P. ligularis -AuNPs. Additionally, the formulation of AuNPs demonstrates strong neuroprotective effects against PPA-induced autism that were arbitrated by a range of different mechanisms, such as anti-inflammatory, antioxidant, neuromodulator, and antiapoptotic effects.

Alterations in Antioxidant Status and Erythrocyte Properties in Children with Autism Spectrum Disorder

Erythrocytes are responsible for the transport of oxygen within the organism, which is particularly important for nerve tissues. Erythrocyte quality has been shown to be deteriorated in oxidative stress conditions. In this study, we measured the same series of oxidative stress markers in plasma and erythrocytes to compare the differences between neurotypical children (controls) and children with autism spectrum disorder (ASD). We also focused on erythrocyte properties including their deformability, osmotic resistance, Na,K-ATPase activity, nitric oxide levels and free radical levels in children with ASD and controls. Greater oxidative damage to proteins and lipids was observed in the erythrocytes than in the plasma of ASD subjects. Additionally, antioxidant enzymes were more active in plasma samples from ASD children than in their erythrocytes. Significantly higher nitric oxide level and Na,K-ATPase enzyme activity were detected in erythrocytes of ASD individuals in comparison with the controls. Changes in oxidative status could at least partially contribute to the deterioration of erythrocyte morphology, as more frequent echinocyte formation was detected in ASD individuals. These alterations are most probably responsible for worsening the erythrocyte deformability observed in children with ASD. We can conclude that abnormalities in antioxidant status and erythrocyte properties could be involved in the pathomechanisms of ASD and eventually contribute to its clinical manifestations.

Lipid Peroxidation via Regulating the Metabolism of Docosahexaenoic Acid and Arachidonic Acid in Autistic Behavioral Symptoms

The association between the lipid peroxidation product malondialdehyde (MDA)-modified low-density lipoprotein (MDA-LDL) and the pathophysiology of autism spectrum disorder (ASD) is unclear. This association was studied in 17 children with ASD and seven age-matched controls regarding autistic behaviors. Behavioral symptoms were assessed using the Aberrant Behavior Checklist (ABC). To compensate for the small sample size, adaptive Lasso was used to increase the likelihood of accurate prediction, and a coefficient of variation was calculated for suitable variable selection. Plasma MDA-LDL levels were significantly increased, and plasma SOD levels were significantly decreased in addition to significantly increased plasma docosahexaenoic acid (DHA) levels and significantly decreased plasma arachidonic acid (ARA) levels in the 17 subjects with ASD as compared with those of the seven healthy controls. The total ABC scores were significantly higher in the ASD group than in the control group. The results of multiple linear regression and adaptive Lasso analyses revealed an association between increased plasma DHA levels and decreased plasma ARA levels, which were significantly associated with total ABC score and increased plasma MDA-LDL levels. Therefore, an imbalance between plasma DHA and ARA levels induces ferroptosis via lipid peroxidation. Decreased levels of α-linolenic acid and γ-linolenic acid may be connected to the total ABC scores with regard to lipid peroxidation.

Iron metabolism in autism spectrum disorder; inference through single nucleotide polymorphisms in key iron metabolism genes

Autism spectrum disorder (ASD) is a heterogeneous group of neurodevelopmental problems with various genetic and environmental components. The ASD diagnosis is based on symptom expression without reliance on any biomarkers. The genetic contributions in ASD remain elusive. Various studies have linked ASD with iron. Since iron plays a crucial role in brain development, neurotransmitter synthesis, neuronal myelination and mitochondrial function, we hypothesized that iron dysregulation in the brain could play a role and contribute to the pathogenesis of ASD. In this study, we investigated single nucleotide polymorphisms in ASD in various iron metabolism genes, including the Transferrin Receptor (TFRC) gene (rs11915082), the Solute Carrier Family 11 Member 2 (SLC11A2) gene (rs1048230 and rs224589), the Solute Carrier Family 40 Member 1 (SLC40A1) gene (rs1439816), and hepcidin antimicrobial peptide (HAMP) gene (rs10421768). We recruited 48 patients with ASD and 88 matched non-ASD controls. Our results revealed a significant difference between ASD and controls in the G allele of the TFRC gene rs11915082, and in the C allele of the SLC40A1 gene rs1439816. In silico analysis demonstrated potential positive role of the indicated genetic variations in ASD development and pathogenesis. These results suggest that specific genetic variations in iron metabolism genes may represent part of early genetic markers for early diagnosis of ASD. A significant effect of SNPs, groups (ASD/control) as well as interaction between SNPs and groups was revealed. Follow-up post hoc tests showed a significant difference between the ASD and control groups in rs11915082 (TFRC gene) and rs1439816 (SLC40A1 gene). Backward conditional logistic regression using both the genotype and allele data showed similar ability in detecting ASD using allel model (Nagelkerke R2 = 0.350 p = 0.967; Variables: rs1439816, rs11915082) compared to genotype model (Nagelkerke R2 = 0.347, p = 0.430; Variables: rs1439816 G, rs1439816 C, rs10421768 A). ROC curve showed 54% sensitivity in detecting ASD compared to 47% for the genotype model. Both models differentiated controls with high accuracy; the allele model had a specificity of 91% compared to 92% for the genotype model. In conclusion, our findings suggest that specific genetic variations in iron metabolism may represent early biomarkers for a diagnosis of ASD. Further research is needed to correlate these markers with specific blood iron indicators and their contribution to brain development and behavior.

Lipid Peroxidation of the Docosahexaenoic Acid/Arachidonic Acid Ratio Relating to the Social Behaviors of Individuals with Autism Spectrum Disorder: The Relationship with Ferroptosis

Polyunsaturated fatty acids (PUFAs) undergo lipid peroxidation and conversion into malondialdehyde (MDA). MDA reacts with acetaldehyde to form malondialdehyde-modified low-density lipoprotein (MDA-LDL). We studied unsettled issues in the association between MDA-LDL and the pathophysiology of ASD in 18 individuals with autism spectrum disorders (ASD) and eight age-matched controls. Social behaviors were assessed using the social responsiveness scale (SRS). To overcome the problem of using small samples, adaptive Lasso was used to enhance the interpretability accuracy, and a coefficient of variation was used for variable selections. Plasma levels of the MDA-LDL levels (91.00 ± 16.70 vs. 74.50 ± 18.88) and the DHA/arachidonic acid (ARA) ratio (0.57 ± 0.16 vs. 0.37 ± 0.07) were significantly higher and the superoxide dismutase levels were significantly lower in the ASD group than those in the control group. Total SRS scores in the ASD group were significantly higher than those in the control group. The unbeneficial DHA/ARA ratio induced ferroptosis via lipid peroxidation. Multiple linear regression analysis and adaptive Lasso revealed an association of the DHA/ARA ratio with total SRS scores and increased MDA-LDL levels in plasma, resulting in neuronal deficiencies. This unbeneficial DHA/ARA-ratio-induced ferroptosis contributes to autistic social behaviors and is available for therapy.

Mouse nerve growth factor suppresses neuronal apoptosis in valproic acid-induced autism spectrum disorder rats by regulating the phosphoinositide-3-kinase/serine/threonine kinase signaling pathway

BACKGROUND

Autism spectrum disorder (ASD) is a group of neurodevelopmental disorders characterized by deficits in social communication and restrictive behaviors. Mouse nerve growth factor (mNGF), a neurotrophic factor, is critical for neuronal growth and survival, and the mNGF treatment is considered a promising therapy for neurodegeneration. In light of this, we aimed to evaluate the effect of mNGF on neurological function in ASD.

METHODS

An ASD rat model was established by intraperitoneal injection of valproic acid (VPA). Social behavior, learning, and memory of the rats were measured. TdT-mediated dUTP Nick-end labeling and Nissl assays were performed to detect neuronal apoptosis and survival in the hippocampus and prefrontal cortex. Apoptosis-related proteins and oxidative stress markers were detected.

RESULTS

mNGF improved locomotor activity, exploratory behavior, social interaction, and spatial learning and memory in VPA-induced ASD rats. In the hippocampus and prefrontal cortex, mNGF suppressed neuronal apoptosis, increased the number of neurons, superoxide dismutase, and glutathione levels, and decreased reactive oxygen species, nitric oxide, TNF-α, and IL-1β levels compared with the VPA group. In addition, mNGF increased the levels of Bcl-2, p-phosphoinositide-3-kinase (PI3K), and p-serine/threonine kinase (Akt), and decreased the levels of Bax and cleaved caspase-3, while the PI3K inhibitor LY294002 reversed these effects.

CONCLUSION

These data suggest that mNGF suppressed neuronal apoptosis and ameliorated the abnormal behaviors in VPA-induced ASD rats, in part, by activating the PI3K/Akt signaling pathway.

Neuroinflammation, Energy and Sphingolipid Metabolism Biomarkers Are Revealed by Metabolic Modeling of Autistic Brains

Autism spectrum disorders (ASD) are a heterogeneous group of neurodevelopmental disorders generally characterized by repetitive behaviors and difficulties in communication and social behavior. Despite its heterogeneous nature, several metabolic dysregulations are prevalent in individuals with ASD. This work aims to understand ASD brain metabolism by constructing an ASD-specific prefrontal cortex genome-scale metabolic model (GEM) using transcriptomics data to decipher novel neuroinflammatory biomarkers. The healthy and ASD-specific models are compared via uniform sampling to identify ASD-exclusive metabolic features. Noticeably, the results of our simulations and those found in the literature are comparable, supporting the accuracy of our reconstructed ASD model. We identified that several oxidative stress, mitochondrial dysfunction, and inflammatory markers are elevated in ASD. While oxidative phosphorylation fluxes were similar for healthy and ASD-specific models, and the fluxes through the pathway were nearly undisturbed, the tricarboxylic acid (TCA) fluxes indicated disruptions in the pathway. Similarly, the secretions of mitochondrial dysfunction markers such as pyruvate are found to be higher, as well as the activities of oxidative stress marker enzymes like alanine and aspartate aminotransferases (ALT and AST) and glutathione-disulfide reductase (GSR). We also detected abnormalities in the sphingolipid metabolism, which has been implicated in many inflammatory and immune processes, but its relationship with ASD has not been thoroughly explored in the existing literature. We suggest that important sphingolipid metabolites, such as sphingosine-1-phosphate (S1P), ceramide, and glucosylceramide, may be promising biomarkers for the diagnosis of ASD and provide an opportunity for the adoption of early intervention for young children.

TF and TCF4 gene polymorphisms are linked to autism spectrum disorder: a case-control study

OBJECTIVE

Although the prevalence of autism spectrum disorder (ASD) is increasing, appropriate diagnosis and prevention strategies are still lacking. This case-control study was designed to explore the association between ASD and the rs1867503 and rs9951150 polymorphisms of the TF and TCF4 genes, respectively.

METHODS

Ninety-six children with ASD and 118 healthy children were recruited and polymerase chain reaction-restriction fragment length polymorphism technique was applied for genotyping.

RESULTS

The frequencies of the mutant allele G were 48% and 44% for the rs1867503 and rs9951150 polymorphisms, respectively. In our analysis, both TF and TCF4 polymorphisms were associated with an increased risk of developing ASD. AG heterozygotes (OR = 3.18), GG mutant homozygotes (OR = 2.62), AG + GG combined genotypes (OR = 2.98), and G mutant alleles of TF rs1867503 (OR = 1.94) were associated with a significantly elevated risk of ASD. Likewise, AG heterozygotes (OR = 2.92), GG mutant homozygotes (OR = 2.36), AG + GG combined genotypes (OR = 2.72), and G minor alleles of TCF4 rs9951150 (OR = 1.92) were associated with a significantly elevated risk of ASD.

CONCLUSIONS

Our results indicate that TF rs1867503 and TCF4 rs9951150 polymorphisms may be strongly associated with the development of ASD in Bangladeshi children.

Repurposing SGLT2 Inhibitors for Neurological Disorders: A Focus on the Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a neurodevelopmental disorder with a substantially increasing incidence rate. It is characterized by repetitive behavior, learning difficulties, deficits in social communication, and interactions. Numerous medications, dietary supplements, and behavioral treatments have been recommended for the management of this condition, however, there is no cure yet. Recent studies have examined the therapeutic potential of the sodium-glucose cotransporter 2 (SGLT2) inhibitors in neurodevelopmental diseases, based on their proved anti-inflammatory effects, such as downregulating the expression of several proteins, including the transforming growth factor beta (TGF-β), interleukin-6 (IL-6), C-reactive protein (CRP), nuclear factor κB (NF-κB), tumor necrosis factor alpha (TNF-α), and the monocyte chemoattractant protein (MCP-1). Furthermore, numerous previous studies revealed the potential of the SGLT2 inhibitors to provide antioxidant effects, due to their ability to reduce the generation of free radicals and upregulating the antioxidant systems, such as glutathione (GSH) and superoxide dismutase (SOD), while crossing the blood brain barrier (BBB). These properties have led to significant improvements in the neurologic outcomes of multiple experimental disease models, including cerebral oxidative stress in diabetes mellitus and ischemic stroke, Alzheimer's disease (AD), Parkinson's disease (PD), and epilepsy. Such diseases have mutual biomarkers with ASD, which potentially could be a link to fill the gap of the literature studying the potential of repurposing the SGLT2 inhibitors' use in ameliorating the symptoms of ASD. This review will look at the impact of the SGLT2 inhibitors on neurodevelopmental disorders on the various models, including humans, rats, and mice, with a focus on the SGLT2 inhibitor canagliflozin. Furthermore, this review will discuss how SGLT2 inhibitors regulate the ASD biomarkers, based on the clinical evidence supporting their functions as antioxidant and anti-inflammatory agents capable of crossing the blood-brain barrier (BBB).

Aberrant Ganglioside Functions to Underpin Dysregulated Myelination, Insulin Signalling, and Cytokine Expression: Is There a Link and a Room for Therapy?

Gangliosides are molecules widely present in the plasma membranes of mammalian cells, participating in a variety of processes, including protein organization, transmembrane signalling and cell adhesion. Gangliosides are abundant in the grey matter of the brain, where they are critically involved in postnatal neural development and function. The common precursor of the majority of brain gangliosides, GM3, is formed by the sialylation of lactosylceramide, and four derivatives of its a- and b-series, GM1, GD1a, GD1b and GT1b, constitute 95% of all the brain gangliosides. Impairments in ganglioside metabolism due to genetic abnormalities of GM-synthases are associated with severe neurological disorders. Apart from that, the latest genome-wide association and translational studies suggest a role of genes involved in brain ganglioside synthesis in less pervasive psychiatric disorders. Remarkably, the most recent animal studies showed that abnormal ganglioside functions result in dysregulated neuroinflammation, aberrant myelination and altered insulin receptor signalling. At the same time, these molecular features are well established as accompanying developmental psychiatric disorders such as attention-deficit hyperactivity disorder (ADHD) and autism spectrum disorders (ASD). This led us to hypothesize a role of deficient ganglioside function in developmental neuropsychiatric disorders and warrants further gene association clinical studies addressing this question. Here, we critically review the literature to discuss this hypothesis and focus on the recent studies on ST3GAL5-deficient mice. In addition, we elaborate on the therapeutic potential of various anti-inflammatory remedies for treatment of developmental neuropsychiatric conditions related to aberrant ganglioside functions.

Measuring Some Oxidative Stress Biomarkers in Autistic Syrian Children and Their Siblings: A Case-Control Study

Objective:

Autism Spectrum Disorder (ASD) is a common neurodevelopmental disorder whose cause remains unknown. Oxidative stress is one of the possible causes of many disorders, including neurological ones. This study aims to measure some oxidative stress biomarkers (Malondialdehyde “MDA,” Advanced Oxidation Protein Product “AOPP,” Glutathione “GSH”) within Syrian children with ASD.

Methods:

MDA, AOPP & GSH were measured in the plasma of a total of 60 children. The ages of the children ranged from 1 to 13 years old. Thirty children had ASD and were compared with 30 controls that don’t have ASD. Fifteen of the controls were siblings of an ASD child, while the remaining 15 had no relations with ASD.

Results:

MDA and AOPP plasma levels were higher in ASD children compared with non-related controls (P = .0001). However, there were no significant differences between MDA and AOPP plasma levels in ASD children in comparison with related controls (P > .05). Alternatively, GSH plasma levels were lower in ASD children compared with both related and non-related controls (P = .0001).

Conclusion:

Further studies are needed to investigate more regarding the diagnostic use of oxidative stress biomarkers, and the therapeutic use of antioxidants in children affected with the autism spectrum disorder.

Electroacupuncture at Zusanli ameliorates the autistic-like behaviors of rats through activating the Nrf2-mediated antioxidant responses

OBJECTIVE

Emerging evidence suggests that acupuncture plays a neuroprotective role in autism. This study aimed to explore the effect of electroacupuncture at Zusanli (ST36) on autistic-like behaviors and the underlying mechanism.

METHOD

Pregnant rats were administered with valproic acid (VPA) on gestational day 12.5 to induce an autism spectrum disorder (ASD) model. The pups were given electroacupuncture at ST36 daily from postnatal day (PND) 28-48. On PND28, the adenoviral vector containing small interfering RNA Nrf2 (Ad-siRNA-Nrf2) was injected into the prefrontal cortex of rats. The behavioral analysis was performed on PND 44-48. On PND48, the animals were euthanized and the brains were collected for further detection. Nissl staining was performed to detect neuronal viability. The biochemical markers of oxidative stress were subsequently measured.

RESULT

Electroacupuncture at ST36 ameliorated the locomotor activity, social behavior, spatial learning and memory and repetitive behavior compared with ASD rats. It was notable that the electroacupuncture decreased oxidative stress markers in the tissues of prefrontal cortex, enhanced translocation of nuclear factor erythroid2-related factor2 (Nrf2) from cytoplasm to nucleus, and up-regulated the levels of NADP(H) quinone oxidoreductase (NQO1) and heme oxygenase (HO-1). However, these effects induced by electroacupuncture at ST36 were abolished after injection of Ad-siRNA-Nrf2.

CONCLUSION

These data suggested that electroacupuncture at ST36 protected nerve function in ASD rats through Nrf2 activation and the antioxidant response.

Altered Blood Brain Barrier Permeability and Oxidative Stress in Cntnap2 Knockout Rat Model

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by three core symptoms, specifically impaired social behavior, stereotypic/repetitive behaviors, and sensory/communication deficits. Although the exact pathophysiology of ASD is still unknown, host genetics, oxidative stress, and compromised blood brain barrier (BBB) have been implicated in predisposition to ASD. With regards to genetics, mutations in the genes such as CNTNAP2 have been associated with increased susceptibility of developing ASD. Although some studies observed conflicting results suggesting no association of CNTNAP2 with ASD, other investigations correlated this gene with autism. In addition, CNTNAP2 mediated signaling is generally considered to play a role in neurological disorders due to its critical role in neurodevelopment, neurotransmission, and synaptic plasticity. In this investigation, we studied BBB integrity and oxidative stress in Cntnap2^−/− rats. We observed that the BBB permeability was significantly increased in Cntnap2^−/− rats compared to littermate wild-type (WT) animals as determined by FITC-dextran and Evans blue assay. High levels of thiobarbituric acid reactive substances and lower amounts of reduced glutathione were observed in brain homogenates of Cntnap2^−/− rats, suggesting oxidative stress. Brain sections from Cntnap2^−/− rats showed intense inducible nitric oxide synthase immunostaining, which was undetectable in WT animals. Quantification of nitric oxide in brain homogenates revealed significantly high levels in Cntnap2^−/− rats compared to the control group. As increased permeability of the BBB and oxidative stress have been observed in ASD individuals, our results suggest that Cntnap2^−/− rats have a high construct and face validity and can be explored to develop effective therapeutic modalities.

Plasma and red blood cell n3 fatty acids correlate positively with the WISC-R verbal and full-scale intelligence quotients and inversely with Conner's parent-rated ADHD index t-scores in children with high functioning autism and Asperger's syndrome

Findings of the fatty acid status of people with autism spectrum disorders have been incongruent perhaps because of the diversity of the condition. A cross-sectional design study was used to  investigated fatty acid levels and relationships between fatty acids, and cognition and behaviour in a homogenous group of children with autism spectrum disorder. Children with Asperger's syndrome (AS) /high functioning autism (n = 44) and healthy siblings (n = 17) were recruited from the Diagnostic and Therapeutic Centre for Children with Autism, Warsaw, Poland. In the AS group, plasma phosphatidylcholine 22:5n3 correlated positively with verbal (r = 0.357, p = 0.019) and full scale (r = 0.402, p = 0.008) IQs, red blood cell phosphatidylcholine 22:5n3 with verbal (r = 0.308, p = 0.044), performance (r = 0.304, p = 0.047) and full scale (r = 0.388, p = 0.011) IQs and red blood cell phosphatidylethanolamine 22:5n3 with verbal (r = 0.390, p = 0.010) and full scale (r = 0.370, p = 0.016) IQs. Whilst, plasma phosphatidycholine 20:5n3 (r = -0.395, p = 0.009), 22:6n3 (r = -0.402, p = 0.007) and total n3 fatty acids (r = -425, p = 0.005), red blood cell phosphatidlycholine 20:5n3 (r = -0.321, p = 0.036) and red blood cell phosphatidylethanolamine 20:5n3 (r = -0.317, p = 0.038), 22:6n3 (r = -0.297, p = 0.05) and total n3 fatty acids (r = -0.306, p = 0.046) correlated inversly with ADHD index. Similarly, inattention was negatively related with plasma phosphatidylcholine 22:6n3 (r = -0.335, p = 0.028), and total n3 fatty acids (r = -0.340, p = 0.026), oppositional with plasma phosphatidylcholine 18:3n3 (r = -0.333, p = 0.029), 20:5n3 (r = -0.365, p = 0.016), total n3 fatty acids (r = -0.293, p < 0.05), red blood cell phosphatidylcholine 18:3n3 (r = -0.337, p = 0.027) and red blood cell ethanolamine 18:3n3 (r = - 0.333, p = 0.029), 20:5n3 (r = -0.328, p = 0.032), 22:6n3 (r = 0.362, p = 0.017) and total n-3 fatty acids (r = -0.298, p < 0.05) and hyperactivity with plasma phosphatidylcholine 22:6n3 (r = -0.320, p = 0.039). In contrast, there were inverse correlations between red blood cell phosphatidylcholine 18:2n6 and performance (r = -0.358, p = 0.019) and full scale (r = -0.320, p = 0.039) IQs, and direct correlations between red blood cell phosphatidylcholine 22:4n6 (r = 0.339, p = 0.026) and 22:5n6 (r = 0.298, p < 0.05) and ADHD index, between red blood cell phosphatidylcholine 22:4n6 (r = 0.308, p = 0.044) and inattention, between plasma phosphatidylcholine 22:4n6 (r = 0.341, p = 0.025), red blood cell phosphatidylcholine 20:4n6 (r = 0.314, p = 0.041) and total n6 fatty acids (r = 0.336, p = 0.028) and oppositional and plasma phosphatidylcholine 20:3n6 (r = 0.362, p = 0.018) and red blood cell phosphatidylcholine 20:3n6 (r = 0.401, p = 0.009) and hyperactivity. The findings of the ethnically homogenous children with Asperger's syndrome/high functioning autism study revealed positive associations between 22:5n3 and cognition, and negative relationships between 20:5n3 and 22:6n3 and behavioural problem. In contrast, cognitive ability and behavioural problems were negatively and positively associated with n6 fatty acids. Further investigation is required to establish whether there a cause and effect relationship. Regardless, it would be prudent to ensure that children with the conditions have optimum n3 PUFA intake.

The ALA5/ALA6/ALA7 repeat polymorphisms of the glutathione peroxidase-1 (GPx1) gene and autism spectrum disorder

Autism is a severe neurodevelopmental disorder leading to deficits in social interaction, communication, and several activities. An increasing number of evidence suggests a role of oxidative stress in the etiology of autism spectrum disorder (ASD). Indeed, impaired antioxidant mechanisms may lead to the inadequate removal of H₂O₂ with a consequent increase in highly active hydroxyl radicals and other reactive oxygen species causing cellular damages. The GPx1 is one of the most important enzymes counteracting oxidative stress. In this work, we investigated a possible correlation between the GCG repeat polymorphism present in the first exon of GPx1 gene encoding a tract of five to seven alanine residues (ALA5, ALA6, and ALA7) and ASD. Our findings highlighted a high frequency of ALA5 allele in ASD subjects. Moreover, proteins corresponding to the three GPx1 variants were produced in vitro, and the evaluation of their activity showed a lower values for GPx1 having ALA5 polymorphism. The comparison of the secondary and tertiary structure predictions revealed an alpha‐helix in correspondence of alanine stretch only in the case of GPx1‐ALA7 variant. Finally, to better investigate protein structure, steady‐state fluorescence measurements of GPx1 intrinsic tryptophan were carried out and the three tested proteins exhibited a different stability under denaturing conditions. This work demonstrates the importance in adopting a multidisciplinary strategy to comprehend the role of GPx1 in ASD.

Results here obtained suggest a possible role of ALA5 GPx1 variant in ASD. However, given the multifactorial nature of autism, this evidence might be a piece of a more complex puzzle being the GPx1 enzyme part of a complex pathway in which several proteins are involved.

Oxidative Stress in Autism Spectrum Disorder-Current Progress of Mechanisms and Biomarkers

Autism spectrum disorder (ASD) is a type of neurodevelopmental disorder that has been diagnosed in an increasing number of children around the world. Existing data suggest that early diagnosis and intervention can improve ASD outcomes. However, the causes of ASD remain complex and unclear, and there are currently no clinical biomarkers for autism spectrum disorder. More mechanisms and biomarkers of autism have been found with the development of advanced technology such as mass spectrometry. Many recent studies have found a link between ASD and elevated oxidative stress, which may play a role in its development. ASD is caused by oxidative stress in several ways, including protein post-translational changes (e.g., carbonylation), abnormal metabolism (e.g., lipid peroxidation), and toxic buildup [e.g., reactive oxygen species (ROS)]. To detect elevated oxidative stress in ASD, various biomarkers have been developed and employed. This article summarizes recent studies about the mechanisms and biomarkers of oxidative stress. Potential biomarkers identified in this study could be used for early diagnosis and evaluation of ASD intervention, as well as to inform and target ASD pharmacological or nutritional treatment interventions.

Profiles of urine and blood metabolomics in autism spectrum disorders

Early diagnosis and treatment for autism spectrum disorder (ASD) pose challenges. The current diagnostic approach for ASD is mainly clinical assessment of patient behaviors. Biomarkers-based identification of ASD would be useful for pediatricians. Currently, there is no specific treatment for ASD, and evidence for the efficacy of alternative treatments remains inconclusive. The prevalence of ASD is increasing, and it is becoming more urgent to find the pathogenesis of such disorder. Metabolomic studies have been used to deeply investigate the alteration of metabolic pathways, including those associated with ASD. Metabolomics is a promising tool for identifying potential biomarkers and possible pathogenesis of ASD. This review comprehensively summarizes and discusses the abnormal metabolic pathways in ASD children, as indicated by evidence from metabolomic studies in urine and blood. In addition, the targeted interventions that could correct the metabolomic profiles relating to the improvement of autistic behaviors in affected animals and humans have been included. The results revealed that the possible underlying pathophysiology of ASD were alterations of amino acids, reactive oxidative stress, neurotransmitters, and microbiota-gut-brain axis. The potential common pathways shared by animal and human studies related to the improvement of ASD symptoms after pharmacological interventions were mammalian-microbial co-metabolite, purine metabolism, and fatty acid oxidation. The content of this review may contribute to novel biomarkers for the early diagnosis of ASD and possible therapeutic paradigms.

Exploring nordihydroguaretic acid (NDGA) as a plausible neurotherapeutic in the experimental paradigm of autism spectrum disorders targeting nitric oxide pathway

The present study investigates the neuro-protective ability of nordihydroguaretic acid (NDGA) in the experimental paradigm of autism spectrum disorders (ASD) and further decipher the nitric oxide pathway's role in its proposed action. An intracerebroventricular infusion of 4 μl of 1 M PPA was given in the lateral ventricle's anterior region to induce autism-like phenotype in male rats. Oral administration of NDGA (5, 10 & 15 mg/kg) was initiated from the 3^rd day lasting till the 28th day. L-NAME (50 mg/kg) and L-Arginine (800 mg/kg) were also given individually and combined to explore NDGA's ability to act via the nitric oxide pathway. Behavior tests for sociability, stereotypy, anxiety, depression, novelty, repetitive and perseverative behavior were carried out between the 14th and 28th day. On the 29th day, animals were sacrificed, and mitochondrial complexes and oxidative stress parameters were evaluated. We also estimated the levels of neuroinflammatory and apoptotic markers such as TNF-α, IL-6, NF-κB, IFN-γ, HSP-70, and caspase-3. To assess the involvement of the nitric oxide pathway, levels of iNOS and homocysteine were estimated. Treatment with NDGA significantly restored behavioral, biochemical, neurological, and molecular deficits. Hence, NDGA can be used as a neurotherapeutic agent in ASD. Targeting nitric oxide pathway mediated oxidative & nitrosative stress responsible for behavioral, biochemical, and molecular alterations via modulating nitric oxide pathway. The evaluation of iNOS and homocysteine levels conclusively establishes the nitric oxide pathway's role in causing behavioral, biochemical & molecular deficits and NDGA's beneficial effect in restoring these alterations.

Lycopene ameliorates propionic acid-induced autism spectrum disorders by inhibiting inflammation and oxidative stress in rats

This study was conducted to study lycopene efficacy in brain-behavior, pro-inflammatory and apoptotic markers, and antioxidant levels in a rodent model. Rats were administered with propionic acid (PPA) (500 mg/kg BW) to induce autism-like disorders, then treated with different lycopene (L) concentrations (5, 10, 20 mg kg^-1  day^-1 ) for 35 days. The groups were: (i);control, (ii);PPA, (iii);PPA + L5, (iv);PPA + L10, and (v);PPA + L20. In this study, serum and brain malondialdehyde (MDA) levels decreased with lycopene supplements compared to the PPA group, similarly to the brain levels of inflammatory factors (IL-1α, IL-8, NF-κB, TNF-α; p < .05). Besides, brain levels of anti-apoptotic Bcl-2 decreased, whereas pro-apoptotic Bax, antioxidant Nrf2, and HO-1 levels in brain increased compared with PPA (p < .05). This study showed that lycopene might have therapeutic value to improve the dysfunctions in learning and memory in a dose-dependent way, along with the antioxidant, anti-inflammatory, and antiapoptotic molecular responses in a rat model of ASD-like disorders. PRACTICAL APPLICATIONS: This study suggested that lycopene can reduce propionic acid (PPA)-induced learning and memory impairment and oxidative damage by participating in multiple biological activities such as antioxidant, and anti-inflammatory effects. Lycopene protects serum and brain tissues against PPA induced oxidative damage in rats. These effects may be realized through up-regulation of the brain Nrf2/HO-1 pathway and down-regulation of the IL-1α, IL-8, TNF-α, and NF-κB levels. Lycopene may also contribute to memory and learning function, apoptotic/antiapoptotic modulation, and antioxidant and possible therapeutic efficacy in PPA-induced- Autism spectrum disorder cases.

The Metallome as a Link Between the "Omes" in Autism Spectrum Disorders

Metal dyshomeostasis plays a significant role in various neurological diseases such as Alzheimer's disease, Parkinson's disease, Autism Spectrum Disorders (ASD), and many more. Like studies investigating the proteome, transcriptome, epigenome, microbiome, etc., for years, metallomics studies have focused on data from their domain, i.e., trace metal composition, only. Still, few have considered the links between other "omes," which may together result in an individual's specific pathologies. In particular, ASD have been reported to have multitudes of possible causal effects. Metallomics data focusing on metal deficiencies and dyshomeostasis can be linked to functions of metalloenzymes, metal transporters, and transcription factors, thus affecting the proteome and transcriptome. Furthermore, recent studies in ASD have emphasized the gut-brain axis, with alterations in the microbiome being linked to changes in the metabolome and inflammatory processes. However, the microbiome and other "omes" are heavily influenced by the metallome. Thus, here, we will summarize the known implications of a changed metallome for other "omes" in the body in the context of "omics" studies in ASD. We will highlight possible connections and propose a model that may explain the so far independently reported pathologies in ASD.

PM2.5 as a potential risk factor for autism spectrum disorder: Its possible link to neuroinflammation, oxidative stress and changes in gene expression

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by behavioral deficits including impairments in social communication, social interaction, and repetitive behaviors. Because the etiology of ASD is still largely unknown, there is no cure for ASD thus far. Although it has been established that genetic components play a vital role in ASD development, the influence of epigenetic regulation induced by environmental factors could also contribute to ASD susceptibility. Accumulated evidence has suggested that exposure to atmospheric particulate matter (PM) in polluted air could affect neurodevelopment, thus possibly leading to ASD. Particles with a size of 2.5 μm (PM_2.5) or less have been shown to have negative effects on human health, and could be linked to ASD symptoms in children. This review summarizes evidence from clinical and animal studies to demonstrate the possible linkage between PM_2.5 exposure and the incidence of ASD in children. An attempt was made to explore the possible mechanisms of this linkage, including changes of gene expression, oxidative stress and neuroinflammation induced by PM_2.5 exposure.

Disruption of circadian rhythm and risk of autism spectrum disorder: role of immune-inflammatory, oxidative stress, metabolic and neurotransmitter pathways

Circadian rhythms in most living organisms are regulated by light and synchronized to an endogenous biological clock. The circadian clock machinery is also critically involved in regulating and fine-tuning neurodevelopmental processes. Circadian disruption during embryonic development can impair crucial phases of neurodevelopment. This can contribute to neurodevelopmental disorders like autism spectrum disorder (ASD) in the offspring. Increasing evidence from studies showing abnormalities in sleep and melatonin as well as genetic and epigenetic changes in the core elements of the circadian pathway indicate a pivotal role of circadian disruption in ASD. However, the underlying mechanistic basis through which the circadian pathways influence the risk and progression of ASD are yet to be fully discerned. Well-recognized mechanistic pathways in ASD include altered immune-inflammatory, nitro oxidative stress, neurotransmission and synaptic plasticity, and metabolic pathways. Notably, all these pathways are under the control of the circadian clock. It is thus likely that a disrupted circadian clock will affect the functioning of these pathways. Herein, we highlight the possible mechanisms through which aberrations in the circadian clock might affect immune-inflammatory, nitro-oxidative, metabolic pathways, and neurotransmission, thereby driving the neurobiological sequelae leading to ASD.

Lipid Peroxidation With Implication of Organic Pollution in Autistic Behaviors

Background

Lipid metabolism has been associated with the development of autism. The omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) readily undergo lipid peroxidation and conversion to malondialdehyde (MDA). MDA-modified low-density lipoprotein (MDA-LDL) is a marker of lipid peroxidation. However, the association between PUFAs and MDA-LDL in the pathophysiology of autism spectrum disorder (ASD) is unclear.

Materials and methods

We studied the association between PUFAs and MDA-LDL in 16 individuals with ASD (mean age: 11.5 ± 5.7 years) and seven age- and sex-matched healthy controls (mean age: 10.0 ± 4.1 years). The Aberrant Behavior Checklist (ABC) was used to assess behavioral symptoms. We overcame the small sample size by using the adaptive LASSO for enhancing the accuracy of prediction and interpretability. We also estimated the coefficient of variation for an appropriate variable selection and compared additional prior studies to support the findings. Thus, we conducted a careful selection of appropriate candidates to account for confounding variables.

Results

The ASD group had significantly higher plasma MDA levels, eicosapentaenoic acid levels, and a higher ratio of plasma docosahexaenoic acid (DHA)/arachidonic acid (ARA) levels than the control group. Plasma levels of the omega-6 PUFA fraction, dihomo-γ-linolenic acid, and superoxide dismutase levels were significantly lower in the ASD group than in the control group. Total ABC scores were significantly higher in the ASD group than in the control group. Multiple linear regression and adaptive LASSO indicated that plasma DHA levels and plasma DHA/ARA ratios were significantly associated with total ABC scores and plasma levels of MDA-LDL.

Conclusion

Increased plasma levels of DHA and DHA/ARA ratio might be related to organic pollution. These neurobiological bases may induce neuronal deficiency associated with autistic behavioral symptoms in individuals with ASD.

The Nrf2 pathway in psychiatric disorders: pathophysiological role and potential targeting

Introduction: All psychiatric disorders exhibit excitotoxicity, mitochondrial dysfunction, inflammation, oxidative stress, and neural damage as their common characteristic. The endogenous nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway is implicated in the defense mechanism against oxidative stress and has a significant role in psychiatric disorders.Areas covered: We explore the role of Nrf2 pathway and its modulators in psychiatric disorders. The literature was searched utilizing various databases such as Embase, Medline, Web of Science, Pub-Med, and Google Scholar from 2010 to 2020. The search included research articles, clinical reports, systematic reviews, and meta-analyses.Expert opinion: Environmental factors and genetic predisposition can be a trigger for the development of psychiatric disorders. Nrf2 downregulates certain inflammatory pathways and upregulates various antioxidant enzymes to maintain a balance. However, its intricate balance with NF-Kβ (Nuclear factor kappa light chain enhancer of activated B cells) and its crosstalk with the transcription factor Nrf2 is critical in severe oxidative stress. Several Nrf2 modulators are now in clinical trials and can help reduce oxidative stress and neuroinflammation. There are immense potential opportunities for these modulators to become a novel therapeutic option.

Urinary and Plasma Antioxidants in Behavioral Symptoms of Individuals With Autism Spectrum Disorder

The balance between antioxidant capacity and oxidative stress-induced free radicals may be crucial in the pathophysiological development factor of autism spectrum disorder (ASD). We measured the following urinary and plasma biomarker levels of oxidative stress and antioxidants. As urinary biomarkers, (1) hexanoyl-lysine (HEL), which is a new biomarker of oxidative stress, (2) the total antioxidant capacity (TAC), and (3) 8-hydroxy-2'-deoxyguanosine (8-OHdG), as a product of oxidative modifications to DNA; and the plasma levels of (4) the antioxidant protein superoxide dismutase (SOD), which is the crucial defense again oxygen reactive species, and (5) transferrin and (6) ceruloplasmin, which are biomarkers of iron and copper neurotransmission and oxidant-antioxidant systems. We examined the relationship between these urinary and plasma biomarkers and behavioral symptoms in 19 individuals with ASD (mean age, 10.8 ± 5.2 years) and 10 age-matched healthy controls (mean age, 14.2 ± 7.0 years). Behavioral symptoms were estimated using the Aberrant Behavior Checklist (ABC). Urinary TAC levels were significantly lower, whereas urinary HEL levels were significantly increased in the ASD group as compared with the control group. The five ABC subscale and total scores were significantly raised in the autism group than in the control group. The results of a linear regression analysis revealed that plasma SOD levels may be a more accurate predictor of differences in ABC scores between individuals with ASD and control individuals. The present study firstly revealed the important findings that the cooperation between the urinary antioxidant TAC and plasma SOD levels may contribute to the ABC subscale scores of stereotypy. Urinary TAC activity and antioxidant protein SOD may be associated with incomplete mineral body store and antioxidant-related transcription factor and browning reactions. Consequently, a critical imbalance between TAC urinary levels and plasma SOD levels may be an important contributor to autistic behavioral symptoms.

High KEAP1, NRF2 and Low HO-1 Serum Levels in Children with Autism

Introduction

The purpose of our study was to investigate heme oxygenase-1 (HO-1), nuclear factor erythroid-2-related factor 2 (NRF2), and kelch-like ECH-associated protein 1 (KEAP1) levels in children with autism spectrum disorder (ASD) and to reveal their association with the severity of autism.

Methods

This study measured serum HO-1, KEAP1, and NRF2 levels in 43 patients with ASD (aged 3-12 years) and in 41 age- and gender-matched healthy controls. ASD severity was rated using the Childhood Autism Rating Scale (CARS). HO-1, KEAP1, and NRF2 levels were determined in the biochemistry laboratory using the ELISA technique.

Results

HO-1 levels were significantly lower in patients aged 3-12 years compared to controls aged 3-12, while KEAP1 and NRF2 levels were significantly higher (p=0.020, p<0.001, and p=0.017, respectively). No correlation was determined between ASD severity on the basis of total CARS scores and HO-1, KEAP1 or NRF2 (p>0.05).

Conclusion

This study suggests that oxidative stress is higher in children with ASD and that HO-1 levels are insufficient to achieve oxidative balance.

In Vitro Modulation of Endogenous Antioxidant Enzyme Activities and Oxidative Stress in Autism Lymphoblastoid Cell Line (ALCL) by Stingless Bee Honey Treatment

Autism has been associated with a low antioxidant defense mechanism, while honey has been known for decades for its antioxidant and healing properties. Determination of stingless bee honey (KH) effects on antioxidant enzyme activities and oxidative damage in Autism Lymphoblastoid Cell Line (ALCL) was performed. ALCL and its normal sibling pair (NALCL) were cultured in RPMI-1640 medium at 37°C and 5% CO₂. ALCL was treated with 400 μg/mL KH (24 h), and oxidative stress marker, malondialdehyde (MDA), and antioxidant enzyme activities (catalase (CAT), glutathione peroxidase (GPx), and superoxide dismutase (SOD)) were measured via enzyme-linked immunosorbent assay (ELISA), while deoxyribonucleic acid (DNA) damage was determined via comet assay. Low SOD activity (p < 0.05) and high MDA level (p < 0.05) were observed in ALCL compared to NALCL. Higher grade (Grades 2 and 3) of DNA damage was highly observed (p < 0.05) in ALCL compared to NALCL, whereas lower grade (Grades 0 and 1) DNA damage was highly detected (p < 0.05) in NALCL compared to ALCL. KH treatment caused a significant increase in SOD and GPx activities (p < 0.05) in ALCL compared to untreated ALCL. Correspondingly, KH treatment reduced the Grade 2 DNA damage (p < 0.05) in ALCL compared to untreated ALCL. CAT activity showed no significant difference between all three groups, while the MDA level showed no significant difference between treated and untreated ALCL. In conclusion, KH treatment significantly reduced the oxidative stress in ALCL by increasing the SOD and GPx antioxidant enzyme activities, while reducing the DNA damage.

The role of glutathione redox imbalance in autism spectrum disorder: A review

The role of glutathione in autism spectrum disorder (ASD) is emerging as a major topic, due to its role in the maintenance of the intracellular redox balance. Several studies have implicated glutathione redox imbalance as a leading factor in ASD, and both ASD and many other neurodevelopmental disorders involve low levels of reduced glutathione (GSH), high levels of oxidized glutathione (GSSG), and abnormalities in the expressions of glutathione-related enzymes in the blood or brain. Glutathione metabolism, through its impact on redox environment or redox-independent mechanisms, interferes with multiple mechanisms involved in ASD pathogenesis. Glutathione-mediated regulation of glutamate receptors [e.g., N-methyl-d-aspartate (NMDA) receptor], as well as the role of glutamate as a substrate for glutathione synthesis, may be involved in the regulation of glutamate excitotoxicity. However, the interaction between glutathione and glutamate in the pathogenesis of brain diseases may vary from synergism to antagonism. Modulation of glutathione is also associated with regulation of redox-sensitive transcription factors nuclear factor kappa B (NF-κB) and activator protein 1 (AP-1) and downstream signaling (proinflammatory cytokines and inducible enzymes), thus providing a significant impact on neuroinflammation. Mitochondrial dysfunction, as well as neuronal apoptosis, may also provide a significant link between glutathione metabolism and ASD. Furthermore, it has been recently highlighted that glutathione can affect and modulate DNA methylation and epigenetics. Review analysis including research studies meeting the required criteria for analysis showed statistically significant differences between the plasma GSH and GSSG levels as well as GSH:GSSG ratio in autistic patients compared with healthy individuals (P = 0.0145, P = 0.0150 and P = 0.0202, respectively). Therefore, the existing data provide a strong background on the role of the glutathione system in ASD pathogenesis. Future research is necessary to investigate the role of glutathione redox signaling in ASD, which could potentially also lead to promising therapeutics.

The role of lipid peroxidation in individuals with autism spectrum disorders

The role of malondialdehyde-modified low-density lipoprotein (MDA-LDL), an oxidized LDL, in the pathophysiology of autism spectrum disorder (ASD) is unclear. We studied association between MDA-LDL and behavioral symptoms in 11 individuals with ASD and 7 age -matched normal controls. Behavioral symptoms were assessed using the Aberrant Behavior Checklists (ABC). Because small sample size in this study, three measures were conducted: first, employment of adaptive Lasso for enhancing the accuracy of prediction and interpretability; second, calculation of coefficient of variation for an appropriate selection of plasma variables; and third, selection of good candidates of plasma variables. Plasma levels of MDA-LDL, eicosapentaenoic acid, docosahexaenoic acid (DHA) and DHA/arachidonic acid ratios were significantly higher, while plasma superoxide dismutase (SOD) levels were significantly lower in the ASD group than in the control group. The total ABC scores were significantly higher in the ASD group than in the control group. Multiple linear regression analysis and the adaptive Lasso revealed association of increased plasma DHA levels with the ABC total scores and increased plasma MDA-LDL levels. Such association between DHA and plasma MDA-LDL levels may contribute to behavior in individuals with ASD.

Whole-Exome Sequencing Identifies Three Candidate Homozygous Variants in a Consanguineous Iranian Family with Autism Spectrum Disorder and Skeletal Problems

Autism spectrum disorder (ASD) is characterized by 3 core symptoms with impaired social communication, repetitive behavior, and/or restricted interests in early childhood. As a complex neurodevelopmental disorder (NDD), the phenotype and severity of autism are extremely heterogeneous. Genetic factors have a key role in the etiology of autism. In this study, we investigated an Azeri Turkish family with 2 ASD-affected individuals to identify probable ASD-causing variants. First, the affected individuals were karyotyped in order to exclude chromosomal abnormalities. Then, whole-exome sequencing was carried out in one affected sibling followed by cosegregation analysis for the candidate variants in the family. In addition, SNP genotyping was carried out in the patients to identify possible homozygosity regions. Both proband and sibling had a normal karyotype. We detected 3 possible causative variants in this family: c.5443G>A; p.Gly1815Ser, c.1027C>T; p.Arg343Trp, and c.382A>G; p.Lys128Glu, which are in the FBN1, TF, and PLOD2 genes, respectively. All of the variants cosegregated in the family, and SNP genotyping revealed that these 3 variants are located in the homozygosity regions. This family serves as an example of a multimodal polygenic risk for a complex developmental disorder. Of these 3 genes, confluence of the variants in FBN1 and PLOD2 may contribute to the autistic features of the patient in addition to skeletal problems. Our study highlights the genetic complexity and heterogeneity of NDDs such as autism. In other words, in some patients with ASD, multiple rare variants in different loci rather than a monogenic state may contribute to the development of phenotypes.

Fluorescent conjugated polymer nanovector for in vivo tracking and regulating the fate of stem cells for restoring infarcted myocardium

Stem cell therapy holds great promise for cardiac regeneration. However, the lack of ability to control stem cell fate after in vivo transplantation greatly restricts its therapeutic outcomes. MicroRNA delivery has emerged as a powerful tool to control stem cell fate for enhanced cardiac regeneration. However, the clinical translation of therapy based on gene-transfected stem cells remains challenging, due to the unknown in vivo behaviors of stem cells. Here, we developed a nano-platform (i.e., PFBT@miR-1-Tat NPs) that can achieve triggered release of microRNA-1 to promote cardiac differentiation of mesenchymal stem cells (MSCs), and long-term tracking of transplanted MSCs through bright and ultra-stable fluorescence of conjugated polymer poly(9,9-dioctylfluorene-alt-benzothiadiazole) (PFBT). We found that PFBT@miR-1-Tat NP-treated MSCs significantly restored the infarcted myocardium by promoting stem cell cardiac differentiation and integration with the in situ cardiac tissues. Meanwhile, MSCs without gene delivery improved the infarcted heart functions mainly through a paracrine effect and blood vessel formation. The developed conjugated polymer nanovector should be a powerful tool for manipulating as well as revealing the fate of therapeutic cells in vivo, which is critical for optimizing the therapeutic route of gene and cell combined therapy and therefore for accelerating clinical translation. STATEMENT OF SIGNIFICANCE: The lack of controllability in stem cell fate and the unclear in vivo cellular behaviors restrict the therapeutic outcomes of stem cell therapy. Herein, we engineered fluorescent conjugated polymer nanoparticles as gene delivery nanovectors with controlled release and high intracellular delivery capability to harness the fate of mesenchymal stem cells (MSCs) in vivo, meanwhile to reveal the cellular mechanism of gene-treated stem cell therapy. As compared with only MSC treatment that improves infarcted myocardium functions through paracrine effect, treatment with conjugated polymer nanovector-treated MSCs significantly restored infarcted myocardium through enhancing MSC cardiac differentiation and integration with the in-situ cardiac tissues. These findings demonstrate that the conjugated polymer nanovector would be a powerful tool in optimizing gene and cell combined therapy.

Oxytocin Differentiated Effects According to the Administration Route in a Prenatal Valproic Acid-Induced Rat Model of Autism

Background and objectives: The hormone oxytocin (OXT) has already been reported in both human and animal studies for its promising therapeutic potential in autism spectrum disorder (ASD), but the comparative effectiveness of various administration routes, whether central or peripheral has been insufficiently studied. In the present study, we examined the effects of intranasal (IN) vs. intraperitoneal (IP) oxytocin in a valproic-acid (VPA) autistic rat model, focusing on cognitive and mood behavioral disturbances, gastrointestinal transit and central oxidative stress status. Materials and Methods: VPA prenatally-exposed rats (500 mg/kg; age 90 days) in small groups of 5 (n = 20 total) were given OXT by IP injection (10 mg/kg) for 8 days consecutively or by an adapted IN pipetting protocol (12 IU/kg, 20 μL/day) for 4 consecutive days. Behavioral tests were performed during the last three days of OXT treatment, and OXT was administrated 20 minutes before each behavioral testing for each rat. Biochemical determination of oxidative stress markers in the temporal area included superoxide dismutase (SOD), glutathione peroxidase (GPx) and malondialdehyde (MDA). A brief quantitative assessment of fecal discharge over a period of 24 hours was performed at the end of the OXT treatment to determine differences in intestinal transit. Results: OXT improved behavioral and oxidative stress status in both routes of administration, but IN treatment had significantly better outcome in improving short-term memory, alleviating depressive manifestations and mitigating lipid peroxidation in the temporal lobes. Significant correlations were also found between behavioral parameters and oxidative stress status in rats after OXT administration. The quantitative evaluation of the gastrointestinal (GI) transit indicated lower fecal pellet counts in the VPA group and homogenous average values for the control and both OXT treated groups. Conclusions: The data from the present study suggest OXT IN administration to be more efficient than IP injections in alleviating autistic cognitive and mood dysfunctions in a VPA-induced rat model. OXT effects on the cognitive and mood behavior of autistic rats may be associated with its effects on oxidative stress. Additionally, present results provide preliminary evidence that OXT may have a balancing effect on gastrointestinal motility.

Oxidative stress, metabolic and mitochondrial abnormalities associated with autism spectrum disorder

Autism spectrum disorder is a neurodevelopmental disorder characterized by impaired development and by abnormal function in regards to social interaction, communication and restricted, repetitive behavior. It affects approximately 1% of the worldwide population. Like other psychiatric disorders the diagnosis is based on observation of, and interview with the patient and next of kin, and diagnostic tests. Many genes have been associated with autism, but only few highly penetrant. Some researchers have instead focused on oxidative stress, metabolic abnormalities and mitochondrial dysfunction as an explanation of the disorder. Currently no cure exists for the disorder, making these abnormalities interesting as they are possibly correctable with supplements or treatment. These various processes cannot be seen independently as they are influencing and interacting with each other. Furthermore many of the metabolic changes seen in autism have also been shown in other psychiatric disorders such as attention deficit hyperactivity disorder, schizophrenia and bipolar disorder along with often comorbid disorders like epilepsy and intellectual disability. As such some of these abnormalities are not specific, however, could indicate a similar mechanism for the development of these disorders, with symptomatology and severity varying according to the location and the amount of damage done to proteins, cells and DNA. Clinical studies trying to treat these abnormalities, have widely been successful in correcting the metabolic abnormalities seen, but only some studies have also shown bettering of autistic symptoms. Hopefully with increased knowledge of the pathophysiology of the disorder, future preventive measures or treatment can be developed.

Oxidative Stress in Autism Spectrum Disorder

According to the United States Centers for Disease Control and Prevention (CDC), as of July 11, 2016, the reported average incidence of children diagnosed with an autism spectrum disorder (ASD) was 1 in 68 (1.46%) among 8-year-old children born in 2004 and living within the 11 monitoring sites' surveillance areas in the United States of America (USA) in 2012. ASD is a multifaceted neurodevelopmental disorder that is also considered a hidden disability, as, for the most part; there are no apparent morphological differences between children with ASD and typically developing children. ASD is diagnosed based upon a triad of features including impairment in socialization, impairment in language, and repetitive and stereotypic behaviors. The increasing incidence of ASD in the pediatric population and the lack of successful curative therapies make ASD one of the most challenging disorders for medicine. ASD neurobiology is thought to be associated with oxidative stress, as shown by increased levels of reactive oxygen species and increased lipid peroxidation, as well as an increase in other indicators of oxidative stress. Children with ASD diagnosis are considered more vulnerable to oxidative stress because of their imbalance in intracellular and extracellular glutathione levels and decreased glutathione reserve capacity. Several studies have suggested that the redox imbalance and oxidative stress are integral parts of ASD pathophysiology. As such, early assessment and treatment of antioxidant status may result in a better prognosis as it could decrease the oxidative stress in the brain before it can induce more irreversible brain damage. In this review, many aspects of the role of oxidative stress in ASD are discussed, taking into account that the process of oxidative stress may be a target for therapeutic interventions.

Differential regulation of Nrf2 is linked to elevated inflammation and nitrative stress in monocytes of children with autism

Autism spectrum disorder (ASD) is a very complex neurodevelopmental disorder characterized by deficits in social and communication skills. Innate immune cells like monocytes are believed to play a cardinal role in neuroimmune inflammation and nitrative stress. On the other hand, Nrf2, a basic leucine zipper transcription factor plays a significant role in protecting the immune cells against inflammation and oxidants. However, its role in monocytes of ASD children and typically developing control (TDC) children has not been elucidated in relation with inflammation and nitrative stress. Therefore, this study was undertaken to evaluate Nrf2 expression/activity along with parameters of inflammation (NFkB, IL-6, IL-1β) and nitrative stress (iNOS, nitrotyrosine) in monocytes of ASD/TDC children. Further, sulforaphane (SFN) was utilized as an Nrf2 activator to assess its effect on above said inflammatory and nitrative stress parameters. Our study shows that monocytes of ASD subjects have decreased Nrf2 expression/activity along with increased inflammation and nitrative stress. Further, monocytes from ASD have deficiency in induction of Nrf2 activity upon stimulation with LPS. However, activation of Nrf2 in vitro by SFN reverses LPS-induced effects on inflammation in monocytes by reduction in NFkB signaling. Further, treatment with SFN also reverses LPS-induced effects on nitrative stress (iNOS, nitrotyrosine) in monocytes of ASD subjects. This study propounds the idea that SFN protects against nitrative stress and inflammation by downregulating oxidative stress and inflammation through blockade of NFkB signaling in autistic children. This may be the reason behind reported ameliorative effects of SFN in ASD subjects.

Erythrocyte deformability in children with autism spectrum disorder: correlation with clinical features

Biomechanical properties of erythrocytes play an important role in health and disease. Deformability represents intrinsic property of erythrocytes to undergo deformation that is crucial for their passage through the narrow capillaries. The erythrocyte damage can lead to compromised tissue perfusion and consequently play a role in the pathogenesis of various diseases including neurological ones. Data available in databases indicate that erythrocytes in autism spectrum disorder (ASD) are altered. This may affect the clinical symptoms of ASD. The aim of our study was to determine erythrocyte deformability in 54 children with ASD and correlate it with clinical symptoms. We found significant negative correlation between erythrocyte deformability and score in C domain of the Autism Diagnostic Interview-Revised (ADI-R) diagnostic tool describing the measure of restrictive, repetitive, and stereotyped behaviors and interests, mainly observable in C1 and C2, but not in C3 and C4 subdomains. This supports the findings of other authors and suggest that behavioral domain C comprises of more subcategories with different underlying etiology. Our results also indicate that abnormalities in erythrocyte deformability may be involved in ASD pathomechanisms and contribute to its clinical manifestation. Further research is necessary to bring more data and identify erythrocyte deformability as prognostic biomarker in ASD.

Metabolic Framework for the Improvement of Autism Spectrum Disorders by a Modified Ketogenic Diet: A Pilot Study

The ketogenic diet (KD) can improve the core features of autism spectrum disorders (ASD) in some children, but the effects on the overall metabolism remain unclear. This pilot study investigated the behavioral parameters in relation to blood metabolites and trace elements in a cohort of 10 typically developed controls (TC) and 17 children with ASD at baseline and following 3 months of treatment with a modified KD regimen. A nontargeted, multiplatform metabolomic approach was employed, including gas chromatography-mass spectrometry, ¹H nuclear magnetic resonance spectroscopy, and inductively coupled plasma-mass spectrometry. The associations among plasma metabolites, trace elements, and behavior scores were investigated. Employing a combination of metabolomic platforms, 118 named metabolites and 73 trace elements were assessed. Relative to TC, a combination of glutamate, galactonate, and glycerol discriminated ASD with 88% accuracy. ASD had higher concentrations of galactose intermediates, gut microbe-derived trimethylamine N-oxide and N-acetylserotonin, and lower concentrations of 3-hydroxybutyrate and selenium at baseline. Following 3 months of KD intervention, the levels of circulating ketones and acetylcarnitine were increased. KD restored lower selenium levels in ASD to that of controls, and correlation analysis identified a novel negative correlation between the changes in selenium and behavior scores. Based on the different behavior responses to KD, we found that high responders had greater concentrations of 3-hydroxybutyrate and ornithine, with lower galactose. These findings enhance our current understanding of the metabolic derangements present in ASD and may be of utility in predicting favorable responses to KD intervention.

Broken by the Cut: A Journey into the Role of Topoisomerase II in DNA Fragility

DNA topoisomerase II (TOP2) plays a critical role in many processes such as replication and transcription, where it resolves DNA structures and relieves torsional stress. Recent evidence demonstrated the association of TOP2 with topologically associated domains (TAD) boundaries and CCCTC-binding factor (CTCF) binding sites. At these sites, TOP2 promotes interactions between enhancers and gene promoters, and relieves torsional stress that accumulates at these physical barriers. Interestingly, in executing its enzymatic function, TOP2 contributes to DNA fragility through re-ligation failure, which results in persistent DNA breaks when unrepaired or illegitimately repaired. Here, we discuss the biological processes for which TOP2 is required and the steps at which it can introduce DNA breaks. We describe the repair processes that follow removal of TOP2 adducts and the resultant broken DNA ends, and present how these processes can contribute to disease-associated mutations. Furthermore, we examine the involvement of TOP2-induced breaks in the formation of oncogenic translocations of leukemia and papillary thyroid cancer, as well as the role of TOP2 and proteins which repair TOP2 adducts in other diseases. The participation of TOP2 in generating persistent DNA breaks and leading to diseases such as cancer, could have an impact on disease treatment and prevention.

Yin-Yang Mechanisms Regulating Lipid Peroxidation of Docosahexaenoic Acid and Arachidonic Acid in the Central Nervous System

Phospholipids in the central nervous system (CNS) are rich in polyunsaturated fatty acids (PUFAs), particularly arachidonic acid (ARA) and docosahexaenoic acid (DHA). Besides providing physical properties to cell membranes, these PUFAs are metabolically active and undergo turnover through the “deacylation-reacylation (Land's) cycle”. Recent studies suggest a Yin-Yang mechanism for metabolism of ARA and DHA, largely due to different phospholipases A₂ (PLA₂s) mediating their release. ARA and DHA are substrates of cyclooxygenases and lipoxygenases resulting in an array of lipid mediators, which are pro-inflammatory and pro-resolving. The PUFAs are susceptible to peroxidation by oxygen free radicals, resulting in the production of 4-hydroxynonenal (4-HNE) from ARA and 4-hydroxyhexenal (4-HHE) from DHA. These alkenal electrophiles are reactive and capable of forming adducts with proteins, phospholipids and nucleic acids. The perceived cytotoxic and hormetic effects of these hydroxyl-alkenals have impacted cell signaling pathways, glucose metabolism and mitochondrial functions in chronic and inflammatory diseases. Due to the high levels of DHA and ARA in brain phospholipids, this review is aimed at providing information on the Yin-Yang mechanisms for regulating these PUFAs and their lipid peroxidation products in the CNS, and implications of their roles in neurological disorders.

Chronic exposure to xenobiotic pollution leads to significantly higher total glutathione and lower reduced to oxidized glutathione ratio in red blood cells of children with autism

Analyses of reduced glutathione (GSH), oxidized glutathione (GSSG), and total glutathione (tGSH) in red blood cell samples from 30 children diagnosed with autism and 30 age, gender, and socioeconomic status matched controls were undertaken. The children's ages ranged from 2 to 9. Samples were obtained from subjects residing in Western Pennsylvania, an area of the United States greatly affected by high levels of mercury deposition and airborne PM 2.5 particulates. Liquid chromatography - mass spectrometry was utilized by following EPA Method 6800 for sample analyses. The children with autism had a significantly lower mean red blood cell (RBC) reduced to oxidized glutathione ratio (GSH/GSSG) compared to the control children (p = 0.025). In addition, compared to the controls, the children with autism had significantly higher RBC tGSH values (p = 0.0076) and GSH values (p = 0.022). These results suggest that exposure to toxic elements may prompt compensatory increases in production of GSH in children with autism in environments higher in toxins. The compensation did not fully correct the anti-oxidant properties of exposure to xenobiotics as demonstrated by the significantly lower GSH/GSSG in children with autism compared to controls. Out of a set of glutathione biomarkers, GSH/GSSG may best determine the degree of compensation for oxidative stress in children with autism.

Dysregulated enzymatic antioxidant network in peripheral neutrophils and monocytes in children with autism

Autism spectrum disorder (ASD) is a neurodevelopmental disorder where immune cells play an important role. Oxidants and pro-inflammatory cytokines generated by innate immune cells have been implicated in the pathogenesis of ASD. Many previous reports have shown the role of various enzymatic antioxidants in the plasma/red blood cells of ASD subjects, however no study so far has evaluated them in peripheral immune cells of innate origin (neutrophils and monocytes) in ASD patients and typically developing control (TDC) children. With this background, our study explored the expression and activities of major enzymatic antioxidants such as superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GR) in peripheral neutrophils and monocytes of TDC/ASD subjects. Our data show that expression and activity of SOD is increased in ASD subjects as compared to TDC children in neutrophils and monocytes. On the other hand, GPx/GR activity is either reduced/unaltered in neutrophils and monocytes of ASD subjects as compared to TDC children. Increased SOD expression is associated with upregulated expression of nitrotyrosine (a marker of oxidant damage) in both innate immune cells of ASD subjects. Our study suggests that despite adaptive antioxidant response, there is an increased oxidative burden in peripheral neutrophils and monocytes of ASD subjects. This suggests that dysregulated enzymatic antioxidant network in peripheral innate immune cells could play a significant role in the pathogenesis of autism.