Arachidonic acid-derived dihydroxy fatty acids in neonatal cord blood relate symptoms of autism spectrum disorders and social adaptive functioning: Hamamatsu Birth Cohort for Mothers and Children (HBC Study).

AIM: Autism spectrum disorder (ASD) is associated with abnormal lipid metabolism, such as a high total ratio of omega-6 to omega-3 in polyunsaturated fatty acids (PUFAs). PUFAs are metabolized to epoxy fatty acids by cytochrome P450 (CYP); then, dihydroxy fatty acid is produced by soluble epoxide hydrolase. This study examined the association between PUFA metabolites in the cord blood and ASD symptoms and adaptive functioning in children. METHODS: This prospective cohort study utilized cord blood to quantify PUFA metabolites of the CYP pathway. The Autism Diagnostic Observation Schedule (ADOS-2) and Vineland Adaptive Behaviors Scales, Second Edition (VABS-II) were used to assess subsequent ASD symptoms and adaptive functioning in children at 6 years. The analysis included 200 children and their mothers. RESULTS: Arachidonic acid-derived diols, 11,12-diHETrE was found to impact ASD symptom severity on the ADOS-2-calibrated severity scores and impairment in the socialization domain as assessed by the VABS-II (P = 0.0003; P = 0.004, respectively). High levels of 11,12-diHETrE impact social affect in ASD symptoms (P = 0.002), while low levels of 8,9-diHETrE impact repetitive/restrictive behavior (P = 0.003). Notably, there was specificity in the association between diHETrE and ASD symptoms, especially in girls. CONCLUSION: These findings suggest that the dynamics of diHETrE during the fetal period is important in the developmental trajectory of children after birth. Given that the role of diol metabolites in neurodevelopment in vivo is completely uncharacterized, the results of this study provide important insight into the role of diHETrE and ASD pathophysiology.

NARP-related alterations in the excitatory and inhibitory circuitry of socially isolated mice: developmental insights and implications for autism spectrum disorder.

Background: Social isolation during critical periods of development is associated with alterations in behavior and neuronal circuitry. This study aimed to investigate the immediate and developmental effects of social isolation on firing properties, neuronal activity-regulated pentraxin (NARP) and parvalbumin (PV) expression in the prefrontal cortex (PFC), social behavior in juvenile socially isolated mice, and the biological relevance of NARP expression in autism spectrum disorder (ASD). Methods: Mice were subjected to social isolation during postnatal days 21-35 (P21-P35) and were compared with group-housed control mice. Firing properties in the PFC pyramidal neurons were altered in P35 socially isolated mice, which might be associated with alterations in NARP and PV expression. Results: In adulthood, mice that underwent juvenile social isolation exhibited difficulty distinguishing between novel and familiar mice during a social memory task, while maintaining similar levels of social interaction as the control mice. Furthermore, a marked decrease in NARP expression in lymphoblastoid cell lines derived from adolescent humans with ASD as compared to typically developing (TD) humans was found. Conclusion: Our study highlights the role of electrophysiological properties, as well as NARP and PV expression in the PFC in mediating the developmental consequences of social isolation on behavior.

Eurycomanone from Eurycoma longifolia Jack upregulates neurotrophin-3 gene expression in retinal Müller cells in vitro.

Photoreceptor degeneration decreases light sensitivity and leads to vision loss and various retinal diseases. Neurotrophin-3, originating from Müller glial cells in the retina, plays a key role in protecting photoreceptors from damage induced by light or hypoxia. This neuroprotective approach is important because there are no established methods to regenerate lost photoreceptors. Dietary supplements are one of the useful methods for improving eye health. Eurycoma longifolia (E. longifolia) Jack, which is native to the tropical forest of Malaysia and other Southeast Asian countries, exhibits several medicinal properties. In the present study, we demonstrated that the water extract of E. longifolia roots enhanced neurotrophin-3 gene expression in primary rat Müller cells. Using a stepwise bioassay-guided fractionation and purification of E. longifolia root extracts, we isolated the active compound underlying neurotrophin-3 gene-enhancing activities. Mass spectrometry and nuclear magnetic resonance spectral data identified the compound as eurycomanone. This study provides evidence for the efficacy of E. longifolia and eurycomanone in enhancing neurotrophin-3 expression in Müller cells in vitro. Although the biological significance of this effect and its underlying mechanism remain to be elucidated, this study suggests that E. longifolia may be promising for improving eye health and must be further investigated.

Interaction of genetic liability for attention deficit hyperactivity disorder (ADHD) and perinatal inflammation contributes to ADHD symptoms in children.

Objective: Genetic and environmental factors contribute to the development of Attention Deficit/Hyperactivity Disorder (ADHD). Perinatal inflammation is one of the promising environmental risk factors for ADHD, but the relationship between the genetic risk for ADHD and perinatal inflammation requires further examination. Methods: A possible gene-environmental interaction between perinatal inflammation and ADHD polygenic risk score (ADHD-PRS) on ADHD symptoms was investigated in children aged 8-9 from the Hamamatsu Birth Cohort for Mothers and Children (N = 531). Perinatal inflammation was evaluated by the level of concentration of three cytokines assayed in umbilical cord blood. The genetic risk for ADHD was assessed by calculating ADHD-PRS for each individual using a previously collected genome-wide association study of ADHD. Results: Perinatal inflammation (ß [SE], 0.263 [0.017]; P < 0.001), ADHD-PRS (ß [SE], 0.116[0.042]; P = 0.006), and an interaction between the two (ß [SE], 0.031[0.011]; P = 0.010) were associated with ADHD symptoms. The association between perinatal inflammation and ADHD symptoms measured by ADHD-PRS was evident only in the two higher genetic risk groups (ß [SE], 0.623[0.122]; P < 0.001 for the medium-high risk group; ß [SE], 0.664[0.152]; P < 0.001 for the high-risk group). Conclusion: Inflammation in the perinatal period both directly elevated ADHD symptoms and magnified the impact of genetic vulnerability on ADHD risk particularly among children aged 8-9 with genetically higher risk for ADHD.

Linoleic acid and linoleate diols in neonatal cord blood influence birth weight.

Background: Low-birth-weight infants exhibit a high risk for postnatal morbidity. Cytochrome P450 (CYP) and epoxide hydrolase (EH) are involved in the metabolism of factors responsible for low-birth-weight in infants. Both CYPs and EHs have high substrate specificity and are involved in polyunsaturated fatty acid (PUFA) metabolism. The CYP pathway produces epoxy fatty acids (EpFAs), which are further degraded by soluble EH (sEH). Additionally, sEH inhibition enhances the action of EpFAs and suppresses inflammatory responses. During pregnancy, excessive activation of maternal inflammatory response is a significant factor associated with low-birth-weight. However, the association of EpFAs, which have potential anti-inflammatory properties, with the low-birth-weight of infants remains uninvestigated. This study aimed to clarify the association between the umbilical cord serum EpFA and low-birth-weight using data obtained from the Hamamatsu Birth Cohort for Mothers and Children (HBC Study) by analyzing the umbilical cord blood samples. Method: We selected a subgroup of 200 infants (106 boys and 94 girls), quantified EpFA concentration in their cord blood samples collected at birth, and examined its correlation with birth weight. Results: The comparison between the low-birth-weight and normal-birth-weight groups revealed no significant correlation between PUFA and EpFA concentrations, but a significant correlation was observed in the linoleate diol concentrations of the two groups. Furthermore, birth weight did not significantly correlate with PUFA, EpFA, and diol concentrations in cord blood; however, multiple regression analysis showed a significant negative correlation of birth weight with the concentration of linoleic acid (LA) (r = -0.101, p = 0.016) as well as LA-derived dihydroxyoctadecenoic acid (diHOME) (r = -0.126, p = 0.007), 9,10-diHOME (r = -0.115, p = 0.014), and 12,13-diHOME (r = -0.126, p = 0.007) after adjusting for obstetric factors, including gestational age, infant's sex, childbirth history, delivery method, and maternal height. Conclusions: Birth weight was significantly correlated with the concentration of LA and linoleate diol diHOME after adjusting for obstetric confounders. Our results show that CYP and sEH involved in PUFA metabolism may influence the birth weight of infants. Further validation is needed to provide insights regarding maternal intervention strategies required to avoid low-birth-weight in infants in the future.

Phldb2 is essential for regulating hippocampal dendritic spine morphology through drebrin in an adult-type isoform-specific manner.

Morphologically dynamic dendritic spines are the major sites of neuronal plasticity in the brain; however, the molecular mechanisms underlying their morphological dynamics have not been fully elucidated. Phldb2 is a protein that contains two predicted coiled-coil domains and the pleckstrin homology domain, whose binding is highly sensitive to PIP3. We have previously demonstrated that Phldb2 regulates synaptic plasticity, glutamate receptor trafficking, and PSD-95 turnover. Drebrin is one of the most abundant neuron-specific F-actin-binding proteins that are pivotal for synaptic morphology and plasticity. We observed that Phldb2 bound to drebrin A (adult-type drebrin), but not to drebrin E (embryonic-type drebrin). In the absence of Phldb2, the subcellular localization of drebrin A in the hippocampal spines and its distribution in the hippocampus were altered. Immature spines, such as the filopodium type, increased relatively in the CA1 regions of the hippocampus, whereas mushroom spines, a typical mature type, decreased in Phldb2-/- mice. Phldb2 suppressed the formation of an abnormal filopodium structure induced by drebrin A overexpression. Taken together, these findings demonstrate that Phldb2 is pivotal for dendritic spine morphology and possibly for synaptic plasticity in mature animals by regulating drebrin A localization.

Fermented rice bran supplementation ameliorates obesity via gut microbiota and metabolism modification in female mice.

We investigated the effects of fermented rice bran (FRB) administration in two groups of C57BL/6J mice. The first group was fed with a high-fat diet, and the second group was fed with a high-fat diet supplemented with the FRB for 8 weeks. FRB supplementation suppressed the high-fat-induced weight gain and considerable alterations in the intestinal microbiota profile in the second group. Among 27 bacterial genera detected in the FRB, only Enterococcus, Lactobacillus, Bacteroides, Prevotella, and the unclassified family Peptostreptococcaceae were detected in mice feces. Their abundances were not particularly increased by FRB supplementation. The abundances of Enterococcus and the unclassified family Peptostreptococcaceae were even suppressed in the second group, suggesting that FRB supplementation didn't cause an addition of beneficial microbiome but inhibit the proliferation of specific bacteria. Fecal succinic acid concentration was significantly decreased in the second group and highly correlated with the relative abundances of Turicibacter, Enterococcus, and the unclassified family Peptostreptococcaceae. A significant increase in fumaric acid and a decrease in xylitol, sorbitol, uracil, glutamic acid, and malic acid levels were observed in the peripheral blood of the second group. FRB supplementation counteracted the high-fat-induced obesity in mice by modulating the gut microbiota and the host metabolism.

Autistic-Like Behavior and Impairment of Serotonin Transporter and AMPA Receptor Trafficking in N-Ethylmaleimide Sensitive Factor Gene-Deficient Mice.

Autism spectrum disorder (ASD), characterized by profound impairment in social interactions and communication skills, is the most common neurodevelopmental disorder. Many studies on the mechanisms underlying the development of ASD have focused on the serotonergic system; however, these studies have failed to completely elucidate the mechanisms. We previously identified N-ethylmaleimide-sensitive factor (NSF) as a new serotonin transporter (SERT)-binding protein and described its importance in SERT membrane trafficking and uptake in vitro. In the present study, we generated Nsf +/- mice and investigated their behavioral, neurotransmitter, and neurophysiological phenotypes in vivo. Nsf +/- mice exhibited abnormalities in sociability, communication, repetitiveness, and anxiety. Additionally, Nsf loss led to a decrease in membrane SERT expression in the raphe and accumulation of glutamate alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors at the synaptic membrane surface in the hippocampal CA1 region. We found that postsynaptic density and long-term depression were impaired in the hippocampal CA1 region of Nsf +/- mice. Taken together, these findings demonstrate that NSF plays a role in synaptic plasticity and glutamatergic and serotonergic systems, suggesting a possible mechanism by which the gene is linked to the pathophysiology of autistic behaviors.

Early Life Stress Alters Gene Expression and Cytoarchitecture in the Prefrontal Cortex Leading to Social Impairment and Increased Anxiety.

Early life stress (ELS), such as abuse, neglect, and maltreatment, exhibits a strong impact on the brain and mental development of children. However, it is not fully understood how ELS affects social behaviors and social-associated behaviors as well as developing prefrontal cortex (PFC). In this study, we performed social isolation on weaned pre-adolescent mice until adolescence and investigated these behaviors and PFC characteristics in adolescent mice. We found the ELS induced social impairments in social novelty, social interaction, and social preference in adolescent mice. We also observed increases of anxiety-like behaviors in ELS mice. In histological analysis, we found a reduced number of neurons and an increased number of microglia in the PFC of ELS mice. To identify the gene associated with behavioral and histological features, we analyzed transcriptome in the PFC of ELS mice and identified 15 differentially expressed genes involved in transcriptional regulation, stress, and synaptic signaling. Our study demonstrates that ELS influences social behaviors, anxiety-like behaviors through cytoarchitectural and transcriptomic alterations in the PFC of adolescent mice.

Characterization of Early Life Stress-Affected Gut Microbiota.

Early life stress (ELS), such as neglect and maltreatment, exhibits a strong impact on the mental and brain development of children. However, it is not fully understood how ELS affects the body and behavior of children. Therefore, in this study, we performed social isolation on weaned pre-adolescent mice and investigated how ELS could affect gut microbiota and mouse behavior. Using the metagenomics approach, we detected an overall ELS-related change in the gut microbiota and identified Bacteroidales and Clostridiales as significantly altered bacterial groups. These metagenomic alterations impaired social behavior in ELS mice, which also correlated with the abundance of Bacteroidales and Clostridiales. Our results demonstrate that ELS alters the gut microbiota and reduces social behavior in adolescent mice.

A loss-of-function variant in SUV39H2 identified in autism-spectrum disorder causes altered H3K9 trimethylation and dysregulation of protocadherin ß-cluster genes in the developing brain.

Recent evidence has documented the potential roles of histone-modifying enzymes in autism-spectrum disorder (ASD). Aberrant histone H3 lysine 9 (H3K9) dimethylation resulting from genetic variants in histone methyltransferases is known for neurodevelopmental and behavioral anomalies. However, a systematic examination of H3K9 methylation dynamics in ASD is lacking. Here we resequenced nine genes for histone methyltransferases and demethylases involved in H3K9 methylation in individuals with ASD and healthy controls using targeted next-generation sequencing. We identified a novel rare variant (A211S) in the SUV39H2, which was predicted to be deleterious. The variant showed strongly reduced histone methyltransferase activity in vitro. In silico analysis showed that the variant destabilizes the hydrophobic core and allosterically affects the enzyme activity. The Suv39h2-KO mice displayed hyperactivity and reduced behavioral flexibility in learning the tasks that required complex behavioral adaptation, which is relevant for ASD. The Suv39h2 deficit evoked an elevated expression of a subset of protocadherin ß (Pcdhb) cluster genes in the embryonic brain, which is attributable to the loss of H3K9 trimethylation (me3) at the gene promoters. Reduced H3K9me3 persisted in the cerebellum of Suv39h2-deficient mice to an adult stage. Congruently, reduced expression of SUV39H1 and SUV39H2 in the postmortem brain samples of ASD individuals was observed, underscoring the role of H3K9me3 deficiency in ASD etiology. The present study provides direct evidence for the role of SUV39H2 in ASD and suggests a molecular cascade of SUV39H2 dysfunction leading to H3K9me3 deficiency followed by an untimely, elevated expression of Pcdhb cluster genes during early neurodevelopment.

GABAA Receptors and Maternally Derived Taurine Regulate the Temporal Specification of Progenitors of Excitatory Glutamatergic Neurons in the Mouse Developing Cortex.

Temporal specification of the neural progenitors (NPs) producing excitatory glutamatergic neurons is essential for histogenesis of the cerebral cortex. Neuroepithelial cells, the primary NPs, transit to radial glia (RG). To coincide with the transition, NPs start to differentiate into neurons, undergoing a switch from symmetric to asymmetric cell division. After the onset of neurogenesis, NPs produce layer-specific neurons in a defined order with precise timing. Here, we show that GABAA receptors (GABAARs) and taurine are involved in this regulatory mechanism. Foetal exposure to GABAAR-antagonists suppressed the transition to RG, switch to asymmetric division, and differentiation into upper-layer neurons. Foetal exposure to GABAAR-agonists caused the opposite effects. Mammalian foetuses are dependent on taurine derived from the mothers. GABA and taurine function as endogenous ligands for GABAARs. Ca2+ imaging showed that NPs principally responded to taurine but not GABA before E13. The histological phenotypes of the taurine transporter knockout mice resembled those of the mice foetally exposed to GABAAR-antagonists. Foetal exposure to GABAAR-modulators resulted in considerable alterations in offspring behavior like core symptoms of autism. These results show that taurine regulates the temporal specification of NPs and that disrupting the taurine-receptor interaction possibly leads to neurodevelopmental disorders.

Zbtb16 regulates social cognitive behaviors and neocortical development.

Zinc finger and BTB domain containing 16 (ZBTB16) play the roles in the neural progenitor cell proliferation and neuronal differentiation during development, however, how the function of ZBTB16 is involved in brain function and behaviors unknown. Here we show the deletion of Zbtb16 in mice leads to social impairment, repetitive behaviors, risk-taking behaviors, and cognitive impairment. To elucidate the mechanism underlying the behavioral phenotypes, we conducted histological analyses and observed impairments in thinning of neocortical layer 6 (L6) and a reduction of TBR1+ neurons in Zbtb16 KO mice. Furthermore, we found increased dendritic spines and microglia, as well as developmental defects in oligodendrocytes and neocortical myelination in the prefrontal cortex (PFC) of Zbtb16 KO mice. Using genomics approaches, we identified the Zbtb16 transcriptome that includes genes involved in neocortical maturation such as neurogenesis and myelination, and both autism spectrum disorder (ASD) and schizophrenia (SCZ) pathobiology. Co-expression networks further identified Zbtb16-correlated modules that are unique to ASD or SCZ, respectively. Our study provides insight into the novel roles of ZBTB16 in behaviors and neocortical development related to the disorders.

Persistent bone resorption lacunae on necrotic bone distinguish bisphosphonate-related osteonecrosis of jaw from denosumab-related osteonecrosis.

BACKGROUND: Bisphosphonate and denosumab are widely used for the treatment of osteoporosis and bone metastasis of cancer to prevent excessive bone resorption. Osteonecrosis of the jaw is a serious adverse effect of bisphosphonate or denosumab referred to as bisphosphonate-related osteonecrosis of the jaw (BRONJ) or denosumab-related osteonecrosis of the jaw (DRONJ), respectively. Since bisphosphonate and denosumab inhibit bone resorption by different mechanism, we evaluated whether these drug types result in different histopathological characteristics related to bone resorption. MATERIALS AND METHODS: We histopathologically investigated 10 cases of BRONJ, DRONJ, and suppurative osteomyelitis. Paraffin sections prepared from decalcified dissected jaw bones were used for histopathological observation, second harmonic generation imaging, and bone histomorphometry. The samples were also observed by a scanning electron microscope. RESULTS: Numerous bone resorption lacunae were observed on the necrotic bone surface in almost all cases of BRONJ; however, such resorption lacunae were limited in DRONJ and suppurative osteomyelitis. Prominent bone resorption lacunae were also confirmed by second harmonic generation imaging and scanning electron microscopy in BRONJ, but not in DRONJ or suppurative osteomyelitis. As determined by bone histomorphometry, the number of bone resorption lacunae and the length of the erosion surface of resorption lacunae were significantly higher in BRONJ group than in the DRONJ and suppurative osteomyelitis groups. These parameters were correlated between the necrotic bones and the vital bones in BRONJ. CONCLUSIONS: Persistent bone resorption lacunae on the necrotic bone surface are unique to BRONJ, providing a basis for distinguishing BRONJ from DRONJ and OM in histopathological diagnosis.

Association of Epigenetic Differences Screened in a Few Cases of Monozygotic Twins Discordant for Attention-Deficit Hyperactivity Disorder With Brain Structures.

The present study examined the relationship between DNA methylation differences and variations in brain structures involved in the development of attention-deficit hyperactivity disorder (ADHD). First, we used monozygotic (MZ) twins discordant (2 pairs of 4 individuals, 2 boys, mean age 12.5 years) for ADHD to identify candidate DNA methylation sites involved in the development of ADHD. Next, we tried to replicate these candidates in a case-control study (ADHD: N = 18, 15 boys, mean age 10.0 years; Controls: N = 62, 40 boys, mean age 13.9 years). Finally, we examined how methylation rates at those sites relate to the degree of local structural alterations where significant differences were observed between cases and controls. As a result, we identified 61 candidate DNA methylation sites involved in ADHD development in two pairs of discordant MZ twins, among which elevated methylation at a site in the sortilin-related Vps10p domain containing receptor 2 (SorCS2) gene was replicated in the case-control study. We also observed that the ADHD group had significantly reduced gray matter volume (GMV) in the precentral and posterior orbital gyri compared to the control group and that this volume reduction was positively associated with SorCS2 methylation. Furthermore, the reduced GMV regions in children with ADHD are involved in language processing and emotional control, while SorCS2 methylation is also negatively associated with emotional behavioral problems in children. These results indicate that SorCS2 methylation might mediate a reduced GMV in the precentral and posterior orbital gyri and therefore influence the pathology of children with ADHD.

Associations Among Maternal Metabolic Conditions, Cord Serum Leptin Levels, and Autistic Symptoms in Children.

INTRODUCTION: Accumulating evidence has shown that maternal metabolic conditions, such as pre-pregnancy overweight, diabetes mellitus, and hypertensive disorders of pregnancy (HDP) are potential risk factors of autism spectrum disorder (ASD). However, it remains unclear how these maternal conditions lead to neurodevelopmental outcomes in the offspring, including autistic symptoms. Leptin, an adipokine that has pro-inflammatory effects and affects fetal neurodevelopment, is a candidate mediator of the association between maternal metabolic factors and an increased risk of ASD. However, whether prenatal exposure to leptin mediates the association between maternal metabolic conditions and autistic symptoms in children has not been investigated yet. METHODS: This study investigated the associations between mothers' metabolic conditions (pre-pregnancy overweight, diabetes mellitus during or before pregnancy, and HDP), leptin concentrations in umbilical cord serum, and autistic symptoms among 762 children from an ongoing cohort study, using generalized structural equation modeling. We used the Social Responsive Scale, Second Edition (SRS-2) at 8-9 years old to calculate total T-scores. Additionally, we used the T-scores for two subdomains: Social Communication and Interaction (SCI) and Restricted Interests and Repetitive Behavior (RRB). RESULTS: Umbilical cord leptin levels were associated with pre-pregnancy overweight [coefficient = 1.297, 95% confidence interval (CI) 1.081-1.556, p = 0.005] and diabetes mellitus (coefficient = 1.574, 95% CI 1.206-2.055, p = 0.001). Furthermore, leptin levels were significantly associated with SRS-2 total T-scores (coefficient = 1.002, 95% CI 1.000-1.004, p = 0.023), SCI scores (coefficient = 1.002, 95% CI 1.000-1.004, p = 0.020), and RRB scores (coefficient = 1.001, 95% CI 1.000-1.003, p = 0.044) in children. Associations between maternal metabolic factors and autistic symptoms were not significant. DISCUSSION: The present study uncovered an association between cord leptin levels and autistic symptoms in children, while maternal metabolic conditions did not have an evident direct influence on the outcome. These results imply that prenatal pro-inflammatory environments affected by maternal metabolic conditions may contribute to the development of autistic symptoms in children. The findings warrant further investigation into the role of leptin in the development of autistic symptoms.

A potential role of fatty acid binding protein 4 in the pathophysiology of autism spectrum disorder.

Autism spectrum disorder is a neurodevelopmental disorder characterized by difficulties in social communication and interaction, as well as repetitive and characteristic patterns of behaviour. Although the pathogenesis of autism spectrum disorder is unknown, being overweight or obesity during infancy and low weight at birth are known as risks, suggesting a metabolic aspect. In this study, we investigated adipose tissue development as a pathophysiological factor of autism spectrum disorder by examining the serum levels of adipokines and other metabolic markers in autism spectrum disorder children (n = 123) and typically developing children (n = 92) at 4-12 years of age. Among multiple measures exhibiting age-dependent trajectories, the leptin levels displayed different trajectory patterns between autism spectrum disorder and typically developing children, supporting an adipose tissue-dependent mechanism of autism spectrum disorder. Of particular interest, the levels of fatty acid binding protein 4 (FABP4) were significantly lower in autism spectrum disorder children than in typically developing subjects, at preschool age (4-6 years old: n = 21 for autism spectrum disorder and n = 26 for typically developing). The receiver operating characteristic curve analysis discriminated autism spectrum disorder children from typically developing children with a sensitivity of 94.4% and a specificity of 75.0%. We re-sequenced the exons of the FABP4 gene in a Japanese cohort comprising 659 autism spectrum disorder and 1000 control samples, and identified two rare functional variants in the autism spectrum disorder group. The Trp98Stop, one of the two variants, was transmitted to the proband from his mother with a history of depression. The disruption of the Fabp4 gene in mice evoked autism spectrum disorder-like behavioural phenotypes and increased spine density on apical dendrites of pyramidal neurons, which has been observed in the postmortem brains of autism spectrum disorder subjects. The Fabp4 knockout mice had an altered fatty acid composition in the cortex. Collectively, these results suggest that an 'adipo-brain axis' may underlie the pathophysiology of autism spectrum disorder, with FABP4 as a potential molecule for use as a biomarker.

Simultaneous evaluation of antioxidative serum profiles facilitates the diagnostic screening of autism spectrum disorder in under-6-year-old children.

This case-control study aimed to assess oxidative stress alterations in autism spectrum disorder (ASD). We used the MULTIS method, an electron spin resonance-based technique measuring multiple free radical scavenging activities simultaneously, in combination with conventional oxidative stress markers to investigate the ability of this MULTIS approach as a non-behavioural diagnostic tool for children with ASD. Serum samples of 39 children with ASD and 58 age-matched children with typical development were analysed. The ASD group showed decreased hydroxyl radical (·OH) and singlet oxygen scavenging activity with increased serum coenzyme Q10 oxidation rate, indicating a prooxidative tendency in ASD. By contrast, scavenging activities against superoxide (O2·-) and alkoxyl radical (RO·) were increased in the ASD group suggesting antioxidative shifts. In the subgroup analysis of 6-year-olds or younger, the combination of ·OH, O2·-, and RO· scavenging activities predicted ASD with high odds ratio (50.4), positive likelihood (12.6), and percentage of correct classification (87.0%). Our results indicate that oxidative stress in children with ASD is not simply elevated but rather shows a compensatory shift. MULTIS measurements may serve as a very powerful non-behavioural tool for the diagnosis of ASD in children.