Pathophysiology of autism spectrum disorders: Revisiting gastrointestinal involvement and immune imbalance

Gastrointestinal problems in a valproic acid-induced rat model of autism: From maternal intestinal health to offspring intestinal function

BACKGROUND

Autism spectrum disorder (ASD) is a developmental disorder characterized by social deficits and repetitive behavior. Gastrointestinal (GI) problems, such as constipation, diarrhea, and inflammatory bowel disease, commonly occur in patients with ASD. Previously, GI problems of ASD patients were attributed to intestinal inflammation and vertical mother-to-infant microbiome transmission.

AIM

To explore whether GI problems in ASD are related to maternal intestinal inflammation and gut microbiota abnormalities.

METHODS

An ASD rat model was developed using valproic acid (VPA). Enzyme-linked immunosorbent assay and fecal 16S rRNA sequencing were used to test GI changes.

RESULTS

VPA exposure during pregnancy led to pathological maternal intestinal changes, resulting in alterations in maternal gut microbiota. Additionally, the levels of inflammatory factors also increased. Moreover, prenatal exposure to VPA resulted in impaired duodenal motility in the offspring as well as increased levels of inflammatory factors.

CONCLUSION

GI problems in ASD may be associated with maternal intestinal inflammation and microbiota abnormality. Future research is required to find more evidence on the etiology and treatment of GI problems in ASD.

Amygdalar neurotransmission alterations in the BTBR mice model of idiopathic autism

Autism Spectrum Disorders (ASD) are principally diagnosed by three core behavioural symptoms, such as stereotyped repertoire, communication impairments and social dysfunctions. This complex pathology has been linked to abnormalities of corticostriatal and limbic circuits. Despite experimental efforts in elucidating the molecular mechanisms behind these abnormalities, a clear etiopathogenic hypothesis is still lacking. To this aim, preclinical studies can be really helpful to longitudinally study behavioural alterations resembling human symptoms and to investigate the underlying neurobiological correlates. In this regard, the BTBR T+ Itpr3tf/J (BTBR) mice are an inbred mouse strain that exhibits a pattern of behaviours well resembling human ASD-like behavioural features. In this study, the BTBR mice model was used to investigate neurochemical and biomolecular alterations, regarding Nerve Growth Factor (NGF) and Brain-Derived Neurotrophic Factor (BDNF), together with GABAergic, glutamatergic, cholinergic, dopaminergic and noradrenergic neurotransmissions and their metabolites in four different brain areas, i.e. prefrontal cortex, hippocampus, amygdala and hypothalamus. In our results, BTBR strain reported decreased noradrenaline, acetylcholine and GABA levels in prefrontal cortex, while hippocampal measurements showed reduced NGF and BDNF expression levels, together with GABA levels. Concerning hypothalamus, no differences were retrieved. As regarding amygdala, we found reduced dopamine levels, accompanied by increased dopamine metabolites in BTBR mice, together with decreased acetylcholine, NGF and GABA levels and enhanced glutamate content. Taken together, our data showed that the BTBR ASD model, beyond its face validity, is a useful tool to untangle neurotransmission alterations that could be underpinned to the heterogeneous ASD-like behaviours, highlighting the crucial role played by amygdala.

Unexplored power of CRISPR-Cas9 in neuroscience, a multi-OMICs review

The neuroscience and neurobiology of gene editing to enhance learning and memory is of paramount interest to the scientific community. The advancements of CRISPR system have created avenues to treat neurological disorders by means of versatile modalities varying from expression to suppression of genes and proteins. Neurodegenerative disorders have also been attributed to non-canonical DNA secondary structures by affecting neuron activity through controlling gene expression, nucleosome shape, transcription, translation, replication, and recombination. Changing DNA regulatory elements which could contribute to the fate and function of neurons are thoroughly discussed in this review. This study presents the ability of CRISPR system to boost learning power and memory, treat or cure genetically-based neurological disorders, and alleviate psychiatric diseases by altering the activity and the irritability of the neurons at the synaptic cleft through DNA manipulation, and also, epigenetic modifications using Cas9. We explore and examine how each different OMIC techniques can come useful when altering DNA sequences. Such insight into the underlying relationship between OMICs and cellular behaviors leads us to better neurological and psychiatric therapeutics by intelligently designing and utilizing the CRISPR/Cas9 technology.

High-fat diet-induced obesity causes intestinal Th17/Treg imbalance that impairs the intestinal barrier and aggravates anxiety-like behavior in mice

The prevalence of autism spectrum disorders (ASD) has been steadily increasing, and growing evidence suggests a link between high-fat diet (HFD), obesity, and ASD; however, the mechanism underlying this association remains elusive. Herein, BTBR T + tf/J (BTBR) inbred mice (a mouse ASD model) and C57Bl/6J (C57) mice were fed an HFD and normal diet (ND) for 8 weeks (groups: C57 + ND, C57 + HFD, BTBR + ND, and BTBR + HFD). Subsequently, mice underwent behavioral assessments, followed by intestinal tissues harvesting to detect expression of intestinal barrier proteins and inflammatory factors and immune cell numbers, and a correlation analysis. HFD-fed BTBR mice developed obesity, elevated blood sugar, significantly aggravated anxiety-like behaviors, impaired intestinal barrier function, intestinal inflammation with elevated CD4+IL17+ T (Th17) cells and reduced CD4+Foxp3+ T (Treg) cells, exhibiting reduced expression of proteins related to AMPK regulatory pathway (AMPK, p-AMPK, SIRT1). Correlation analysis revealed that the degree of behavioral anxiety, the degree of intestinal barrier damage, the severity of intestinal inflammation, and the degree of immune cell imbalance positively correlated with each other. Accordingly, HFD-induced obesity may cause intestinal Th17/Treg imbalance via the AMPK-SIRT1 pathway, leading to an inflammatory environment in the intestine, impairing intestinal barrier function, and ultimately aggravating anxiety-like behaviors in mice.

GABA-transaminase: A Key Player and Potential Therapeutic Target for Neurological Disorders

Neurological disorders such as epilepsy, autism, Huntington's disease, multiple sclerosis, and Alzheimer's disease alter brain functions like cognition, mood, movements, and language, severely compromising the well-being of persons, suffering from their negative effects. The neurotransmitters (GABA, glutamate, norepinephrine, dopamine) are found to be involved in neuronal signaling and neurotransmission. GABA, a "commanding neurotransmitter" is directly or indirectly associated with various neurological disorders. GABA is metabolized to succinic semialdehyde by a mitochondrial gamma-aminobutyric acid-transaminase (GABA-T) enzyme. Therefore, the alterations in the GABA performance in the distinct regions of the brain via GABA-T overstimulation or inhibition would play a vital role in the pathogenesis of various neurological disorders. This review emphasizes the leading participation of GABA-T in neurological disorders like Huntington's disease, epilepsy, autism, Alzheimer's disease, and multiple sclerosis. In Huntington's disease, epilepsy, and multiple sclerosis, the surfeited performance of GABA-T results in diminished levels of GABA, whereas in autism, the subsidence of GABA-T activity causes the elevation in GABA contents, which is responsible for behavioral changes in these disorders. Therefore, GABA-T inhibitors (in Huntington's disease, epilepsy, and multiple sclerosis) or agonists (in autism) can be used therapeutically. In the context of Alzheimer's disease, some researchers favor the stimulation of GABA-T activity whereas some disagree with it. Therefore, the activity of GABA-T concerning Alzheimer's disease is still unclear. In this way, studies of GABA-T enzymatic activity in contrast to neurological disorders could be undertaken to understand and be considered a therapeutic target for several GABA-ergic CNS diseases.

Host fecal DNA specific methylation signatures mark gut dysbiosis and inflammation in children affected by autism spectrum disorder

The gut-brain axis involves several bidirectional pathway communications including microbiome, bacterial metabolites, neurotransmitters as well as immune system and is perturbed both in brain and in gastrointestinal disorders. Consistently, microbiota-gut-brain axis has been found altered in autism spectrum disorder (ASD). We reasoned that such alterations occurring in ASD may impact both on methylation signatures of human host fecal DNA (HFD) and possibly on the types of human cells shed in the stools from intestinal tract giving origin to HFD. To test this hypothesis, we have performed whole genome methylation analysis of HFD from an age-restricted cohort of young children with ASD (N = 8) and healthy controls (N = 7). In the same cohort we have previously investigated the fecal microbiota composition and here we refined such analysis and searched for eventual associations with data derived from HFD methylome analysis. Our results showed that specific epigenetic signatures in human fecal DNA, especially at genes related to inflammation, associated with the disease. By applying methylation-based deconvolution algorithm, we found that the HFD derived mainly from immune cells and the relative abundance of those differed between patients and controls. Consistently, most of differentially methylated regions fitted with genes involved in inflammatory response. Interestingly, using Horvath epigenetic clock, we found that ASD affected children showed both epigenetic and microbiota age accelerated. We believe that the present unprecedented approach may be useful for the identification of the ASD associated HFD epigenetic signatures and may be potentially extended to other brain disorders and intestinal inflammatory diseases.

Autism Spectrum Disorders: A Recent Update on Targeting Inflammatory Pathways with Natural Anti-Inflammatory Agents

Autism spectrum disorder (ASD) is a heterogeneous category of developmental psychiatric disorders which is characterized by inadequate social interaction, less communication, and repetitive phenotype behavior. ASD is comorbid with various types of disorders. The reported prevalence is 1% in the United Kingdom, 1.5% in the United States, and ~0.2% in India at present. The natural anti-inflammatory agents on brain development are linked to interaction with many types of inflammatory pathways affected by genetic, epigenetic, and environmental variables. Inflammatory targeting pathways have already been linked to ASD. However, these routes are diluted, and new strategies are being developed in natural anti-inflammatory medicines to treat ASD. This review summarizes the numerous preclinical and clinical studies having potential protective effects and natural anti-inflammatory agents on the developing brain during pregnancy. Inflammation during pregnancy activates the maternal infection that likely leads to the development of neuropsychiatric disorders in the offspring. The inflammatory pathways have been an effective target for the subject of translational research studies on ASD.

Folate in maternal rheumatoid arthritis-filial autism spectrum disorder continuum

Rheumatoid Arthritis (RA) is an inflammatory autoimmune disease that affects women three times more than men. Epidemiological studies found that the incidence of Autism Spectrum Disorder (ASD), a neurological and developmental disorder, in children born to mothers suffering from RA is higher compared with the control population. Considering that the pathogenesis of ASD could be traced back to pregnancy and in uterine conditions, and the evidence of reduced folate levels in the brain of ASD-affected children, we aimed to study the role of folate, as an important nutritional factor during pregnancy, in associating maternal RA to ASD development in the offspring. Folate balance during RA could be influenced twice, initially during the immune activation associated with disease onset, and later during the treatment with anti-folate drugs, with a potential consequence of folate deficiency. Maternal folate deficiency during pregnancy could increase homocysteine levels, oxidative stress, and global DNA hypomethylation, all known risk factors in ASD pathogenesis. These effects could be intensified by genetic polymorphisms in the folate system, which were also found as genetic risk factors for both RA and ASD. The available evidence suggests that folate level as an important factor during RA, pregnancy and ASD could have pathological and therapeutical significance and should be carefully monitored and investigated in the RA-pregnancy-ASD axis.

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

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

The Role of Microbiome in Brain Development and Neurodegenerative Diseases

Hundreds of billions of commensal microorganisms live in and on our bodies, most of which colonize the gut shortly after birth and stay there for the rest of our lives. In animal models, bidirectional communications between the central nervous system and gut microbiota (Gut-Brain Axis) have been extensively studied, and it is clear that changes in microbiota composition play a vital role in the pathogenesis of various neurodevelopmental and neurodegenerative disorders, such as Autism Spectrum Disorder, Alzheimer's disease, Parkinson's disease, Multiple Sclerosis, Amyotrophic Lateral Sclerosis, anxiety, stress, and so on. The makeup of the microbiome is impacted by a variety of factors, such as genetics, health status, method of delivery, environment, nutrition, and exercise, and the present understanding of the role of gut microbiota and its metabolites in the preservation of brain functioning and the development of the aforementioned neurological illnesses is summarized in this review article. Furthermore, we discuss current breakthroughs in the use of probiotics, prebiotics, and synbiotics to address neurological illnesses. Moreover, we also discussed the role of boron-based diet in memory, boron and microbiome relation, boron as anti-inflammatory agents, and boron in neurodegenerative diseases. In addition, in the coming years, boron reagents will play a significant role to improve dysbiosis and will open new areas for researchers.

Tetrahydrobiopterin and Its Multiple Roles in Neuropsychological Disorders

Tetrahydrobiopterin (BH4) is a multifunctional co-factor of various enzymes and a substantial amount of studies have shown BH4 as a key regulator in the synthesis of neurotransmitters such as serotonin, nor-epinephrine as well as dopamine. The imbalance of BH4 may affect neurotransmitter production which can lead to many abnormalities in CNS. This article reviews the role of BH4 in neurodegenerative and neurodevelopmental disorders. We focus on the therapeutic potential of BH4 in various brain diseases that involves neurotransmitters and attempt to address how the modulation of BH4 may provide a novel strategy in various neuropsychological conditions.

Saudi Experts Consensus on Diagnosis and Management of Pediatric Functional Constipation

Although functional gastrointestinal disorders (FGIDs) are very common in pediatric patients, there is a scarcity of published epidemiologic data, characteristics, and management patterns from Saudi Arabia, which is the 2nd largest Arabic country in terms of area and the 6th largest Arabic country in terms of population, with 10% of its population aged <5 years. Functional constipation (FC) is an FGID that has shown a rising prevalence among Saudi infants and children in the last few years, which urges us to update our clinical practices. Nine pediatric consultants attended two advisory board meetings to discuss and address current challenges, provide solutions, and reach a Saudi national consensus for the management of pediatric constipation. The pediatric consultants agreed that pediatricians should pay attention to any alarming signs (red flags) found during history taking or physical examinations. They also agreed that the Rome IV criteria are the gold standard for the diagnosis of pediatric FC. Different therapeutic options are available for pediatric patients with FC. Dietary treatment is recommended for infants with constipation for up to six months of age. When non-pharmacological interventions fail to improve FC symptoms, pharmacological treatment with laxatives is indicated. First, the treatment is aimed at disimpaction to remove fecal masses. This is achieved by administering a high dose of oral polyethylene glycol (PEG) or lactulose for a few days. Subsequently, maintenance therapy with PEG should be initiated to prevent the re-accumulation of feces. In addition to PEG, several other options may be used, such as Mg-rich formulas or stimulant laxatives. However, rectal enemas and suppositories are usually reserved for cases that require acute pain relief. In contrast, infant formulas that contain prebiotics or probiotics have not been shown to be effective in infant constipation, while the use of partially hydrolyzed formula is inconclusive. These clinical practice recommendations are intended to be adopted by pediatricians and primary care physicians across Saudi Arabia.

Early Prediction and Evaluation of Risk of Autism Spectrum Disorders

Autism is a neuro-developmental condition that first appears at less than three years of age. Autism spectrum disorders (ASD) include several symptoms, such as social communication impairment, stereotyping behaviors, speech abnormalities, and impairment of eye contact. Its prevalence has increased recently, and several factors play a role in increasing the risk of autism. Multiple studies and research explain the factors affecting the rate of autism, and in this article, we will review most of these factors. The aim of this review article is to increase awareness of the problem of autism and provide scientifically relevant information about the etiology, pathogenesis, risk factors, and management of ASD. Our perception of autism has evolved over time. A few years ago, the condition was nothing more than an unrecognized developmental delay, generally with intellectual disabilities. Today, it is recognized as a major public health issue and a topic of much research. Researchers have struggled to find a cause for ASD, and numerous treatments have been developed to maximize the potential to learn and become socially fluent, no matter how strong the impairments may be. Although there is no cure, there have been significant strides in identifying and developing treatments. Early prediction of autism is beneficial in an individual's treatment, which can be carried out by recognizing the risk factors of infants, thus leading to improved outcomes or even a complete cure. The prevalence of ASD has increased, and earlier prediction leads to the best outcomes.

Cellular and molecular mechanisms underlying autism spectrum disorders and associated comorbidities: A pathophysiological review

Autism spectrum disorders (ASD) are a group of neurodevelopmental disorders that develop in early life due to interaction between several genetic and environmental factors and lead to alterations in brain function and structure. During the last decades, several mechanisms have been placed to explain the pathogenesis of autism. Unfortunately, these are reported in several studies and reviews which make it difficult to follow by the reader. In addition, some recent molecular mechanisms related to ASD have been unrevealed. This paper revises and highlights the major common molecular mechanisms responsible for the clinical symptoms seen in people with ASD, including the roles of common genetic factors and disorders, neuroinflammation, GABAergic signaling, and alterations in Ca⁺² signaling. Besides, it covers the major molecular mechanisms and signaling pathways involved in initiating the epileptic seizure, including the alterations in the GABAergic and glutamate signaling, vitamin and mineral deficiency, disorders of metabolism, and autoimmunity. Finally, this review also discusses sleep disorder patterns and the molecular mechanisms underlying them.

Is the Gut Microbiota a Neglected Aspect of Gut and Brain Disorders?

The gut microbiota is a quickly developing bacterial ecosystem with biodiversity. It is an adaptive immunity that varies with food intake, environmental conditions, and human habits, among other factors. Various external stimuli, such as drugs, can influence the gut microbial environment and lead to gut dysbiosis. Recently, gut dysbiosis has been identified as an important factor that leads to several diseases either by the released metabolites or by the gut neuronal connection. In brain disorders, gut dysbiosis is involved in neuropsychiatric manifestations, including autism spectrum disorder, anxiety, and depression by interfering with neurotransmitter homeostasis, and neurodegenerative diseases, such as Alzheimer’s disease and Parkinson’s disease by releasing abnormal metabolites from the gut. Gut dysbiosis has been documented in gut disorders, including inflammatory bowel disease or irritable bowel syndrome. Immune cells in the gut are modulated by external factors such as stress, diet, and drugs to produce inflammatory cytokines, including interleukins (IL-4, IL-6, IL-17, IL-23, etc.). Inflammatory cytokines lead to a cascade of events, which lead to various ailments in the bowel. Beneficial bacteria in the form of probiotics ameliorate the condition and have healthful effects in disease conditions. This warrants further research to identify newer therapeutic strategies for diseases that cannot be cured or are difficult to treat.

Dietary Patterns, Eating Behavior, and Nutrient Intakes of Spanish Preschool Children with Autism Spectrum Disorders

Eating behavior problems are characteristic of children with autism spectrum disorders (ASD) with a highly restricted range of food choices, which may pose an associated risk of nutritional problems. Hence, detailed knowledge of the dietary patterns (DPs) and nutrient intakes of ASD patients is necessary to carry out intervention strategies if required. The present study aimed to determine the DPs and macro-and micronutrient intakes in a sample of Spanish preschool children with ASD compared to typically developing control children. Fifty-four children with ASD (two to six years of age) diagnosed with ASD according to the Diagnostic Manual-5 criteria), and a control group of 57 typically developing children of similar ages were recruited. A validated food frequency questionnaire was used, and the intake of energy and nutrients was estimated through three non-consecutive 24-h dietary registrations. DPs were assessed using principal component analysis and hierarchical clustering analysis. Children with ASD exhibited a DP characterized by high energy and fat intakes and a low intake of vegetables and fruits. Likewise, meat intake of any type, both lean and fatty, was associated with higher consumption of fish and dietary fat. Furthermore, the increased consumption of dairy products was associated with increased consumption of cereals and pasta. In addition, they had frequent consumption of manufactured products with poor nutritional quality, e.g., beverages, sweets, snacks and bakery products. The percentages of children with ASD complying with the adequacy of nutrient intakes were higher for energy, saturated fat, calcium, and vitamin C, and lower for iron, iodine, and vitamins of group B when compared with control children. In conclusion, this study emphasizes the need to assess the DPs and nutrient intakes of children with ASD to correct their alterations and discard some potential nutritional diseases.

Molecular Mechanisms of Aberrant Neuroplasticity in Autism Spectrum Disorders (Review)

This review presents the analysis and systematization of modern data on the molecular mechanisms of autism spectrum disorders (ASD) development. Polyetiology and the multifactorial nature of ASD have been proved. The attempt has been made to jointly review and systematize current hypotheses of ASD pathogenesis at the molecular level from the standpoint of aberrant brain plasticity. The mechanism of glutamate excitotoxicity formation, the effect of imbalance of neuroactive amino acids and their derivatives, neurotransmitters, and hormones on the ASD formation have been considered in detail. The strengths and weaknesses of the proposed hypotheses have been analyzed from the standpoint of evidence-based medicine. The conclusion has been drawn on the leading role of glutamate excitotoxicity as a biochemical mechanism of aberrant neuroplasticity accompanied by oxidative stress and mitochondrial dysfunction. The mechanism of aberrant neuroplasticity has also been traced at the critical moments of the nervous system development taking into account the influence of various factors of the internal and external environment. New approaches to searching for ASD molecular markers have been considered.

Artificial intelligence and placental DNA methylation: newborn prediction and molecular mechanisms of autism in preterm children

BACKGROUND

Autism Spectrum Disorder (ASD) represents a heterogeneous group of disorders with a complex genetic and epigenomic etiology. DNA methylation is the most extensively studied epigenomic mechanism and correlates with altered gene expression. Artificial intelligence (AI) is a powerful tool for group segregation and for handling the large volume of data generated in omics experiments.

METHODS

We performed genome-wide methylation analysis for differential methylation of cytosine nucleotide (CpG) was performed in 20 postpartum placental tissue samples from preterm births. Ten newborns went on to develop autism (Autistic Disorder subtype) and there were 10 unaffected controls. AI including Deep Learning (AI-DL) platforms were used to identify and rank cytosine methylation markers for ASD detection. Ingenuity Pathway Analysis (IPA) to identify genes and molecular pathways that were dysregulated in autism.

RESULTS

We identified 4870 CpG loci comprising 2868 genes that were significantly differentially methylated in ASD compared to controls. Of these 431 CpGs met the stringent EWAS threshold (p-value <5 × 10^-8) along with ≥10% methylation difference between CpGs in cases and controls. DL accurately predicted autism with an AUC (95% CI) of 1.00 (1-1) and sensitivity and specificity of 100% using a combination of 5 CpGs [cg13858611 (NRN1), cg09228833 (ZNF217), cg06179765 (GPNMB), cg08814105 (NKX2-5), cg27092191 (ZNF267)] CpG markers. IPA identified five prenatally dysregulated molecular pathways linked to ASD.

CONCLUSIONS

The present study provides substantial evidence that epigenetic differences in placental tissue are associated with autism development and raises the prospect of early and accurate detection of the disorder.

Allergic diseases influence symptom severity and T lymphocyte subgroups of children with tic disorders

Tic disorders (TD) are childhood-onset neurological disorders. Immune system dysregulation has been postulated to play a role in TD, and its mechanisms likely involve dysfunctional neural-immune cross-talk, which ultimately leads to altered maturation of the brain pathways that control different TD clinical manifestations and behavioral and emotional damages. Clinical studies have demonstrated an association between TD and allergies and overactive immune responses at a systemic level. In this study, the Yale Global Tic Severity Scale was taken as a global measure of tic severity. Compared with the control group, the group of children with TD plus allergic diseases displayed significantly increased Yale total scores (p<0.05), which suggests that children with TD plus allergic diseases have heavier tic symptoms. Both motor and vocal tic scores are higher in the group of children with TD plus allergy compared with the control group. We counted immune cell subpopulations using FACS. T lymphocyte subset comparison of CD3, CD4, CD8, and CD4:CD8 expression ratios revealed that the level of CD3, CD4, and CD4:CD8 in children with TD plus allergic diseases was significantly lower than those of children with TD without allergic diseases. These differences were statistically significant (p<0.05) and suggest that children with TD plus allergic diseases have imbalanced T lymphocyte subsets. We concluded that allergy increased the severity of TD through an imbalance in cellular immunity. Studies need to be done to show whether treatment of allergic symptoms leads to a decrease in TD manifestations.

Potential importance of supplementation with zinc for autism spectrum disorder

Zinc is an essential micronutrient for cellular proliferation and subsequent body and brain development. Zinc deficiency is becoming a major public health issue equally in under-developed and developed countries. The lack of sufficient zinc, whether related to environmental or internal factors, is an important environmental stressor that is eligible to become elucidated as a contributing factor for the pathogenesis of autism spectrum disorder (ASD). The aim of this manuscript is to briefly overview available data regarding the relationship of zinc deficiency with the development of ASD and to relate these data with currently known pathogenetic mechanisms of this disorder namely brain growth disturbances and neuropeptides secretion. Zinc deficiency impacts brain connectivity and growth and alters adequate neurotransmission. In addition, zinc deficiency may indirectly act on the brain by disturbing the immune system and by altering the normal gut-brain connection. Zinc seems to be important for the social effect of neuropeptides. Zinc supplementation in pregnant women and newborn children with the aim of preventing ASD needs further consideration.

Perinatal Dietary Polyunsaturated Fatty Acids in Brain Development, Role in Neurodevelopmental Disorders

n-3 and n-6 polyunsaturated fatty acids (PUFAs) are essential fatty acids that are provided by dietary intake. Growing evidence suggests that n-3 and n-6 PUFAs are paramount for brain functions. They constitute crucial elements of cellular membranes, especially in the brain. They are the precursors of several metabolites with different effects on inflammation and neuron outgrowth. Overall, long-chain PUFAs accumulate in the offspring brain during the embryonic and post-natal periods. In this review, we discuss how they accumulate in the developing brain, considering the maternal dietary supply, the polymorphisms of genes involved in their metabolism, and the differences linked to gender. We also report the mechanisms linking their bioavailability in the developing brain, their transfer from the mother to the embryo through the placenta, and their role in brain development. In addition, data on the potential role of altered bioavailability of long-chain n-3 PUFAs in the etiologies of neurodevelopmental diseases, such as autism, attention deficit and hyperactivity disorder, and schizophrenia, are reviewed.

Genetic Approaches Using Zebrafish to Study the Microbiota-Gut-Brain Axis in Neurological Disorders

The microbiota-gut-brain axis (MGBA) is a bidirectional signaling pathway mediating the interaction of the microbiota, the intestine, and the central nervous system. While the MGBA plays a pivotal role in normal development and physiology of the nervous and gastrointestinal system of the host, its dysfunction has been strongly implicated in neurological disorders, where intestinal dysbiosis and derived metabolites cause barrier permeability defects and elicit local inflammation of the gastrointestinal tract, concomitant with increased pro-inflammatory cytokines, mobilization and infiltration of immune cells into the brain, and the dysregulated activation of the vagus nerve, culminating in neuroinflammation and neuronal dysfunction of the brain and behavioral abnormalities. In this topical review, we summarize recent findings in human and animal models regarding the roles of the MGBA in physiological and neuropathological conditions, and discuss the molecular, genetic, and neurobehavioral characteristics of zebrafish as an animal model to study the MGBA. The exploitation of zebrafish as an amenable genetic model combined with in vivo imaging capabilities and gnotobiotic approaches at the whole organism level may reveal novel mechanistic insights into microbiota-gut-brain interactions, especially in the context of neurological disorders such as autism spectrum disorder and Alzheimer's disease.

Oxidative stress marker aberrations in children with autism spectrum disorder: a systematic review and meta-analysis of 87 studies (N = 9109)

There is increasing awareness that oxidative stress may be implicated in the pathophysiology of autism spectrum disorder (ASD). Here we aimed to investigate blood oxidative stress marker profile in ASD children by a meta-analysis. Two independent investigators systematically searched Web of Science, PubMed, and Cochrane Library and extracted data from 87 studies with 4928 ASD children and 4181 healthy control (HC) children. The meta-analysis showed that blood concentrations of oxidative glutathione (GSSG), malondialdehyde, homocysteine, S-adenosylhomocysteine, nitric oxide, and copper were higher in children with ASD than that of HC children. In contrast, blood reduced glutathione (GSH), total glutathione (tGSH), GSH/GSSG, tGSH/GSSG, methionine, cysteine, vitamin B9, vitamin D, vitamin B12, vitamin E, S-adenosylmethionine/S-adenosylhomocysteine, and calcium concentrations were significantly reduced in children with ASD relative to HC children. However, there were no significance differences between ASD children and HC children for the other 17 potential markers. Heterogeneities among studies were found for most markers, and meta-regressions indicated that age and publication year may influence the meta-analysis results. These results therefore clarified blood oxidative stress profile in children with ASD, strengthening clinical evidence of increased oxidative stress implicating in pathogenesis of ASD. Additionally, given the consistent and large effective size, glutathione metabolism biomarkers have the potential to inform early diagnosis of ASD.

Understanding Abnormal SMO-SHH Signaling in Autism Spectrum Disorder: Potential Drug Target and Therapeutic Goals

Autism is a multifactorial neurodevelopmental condition; it demonstrates some main characteristics, such as impaired social relationships and increased repetitive behavior. The initiation of autism spectrum disorder is mostly triggered during brain development by the deregulation of signaling pathways. Sonic hedgehog (SHH) signaling is one such mechanism that influences neurogenesis and neural processes during the development of the central nervous system. SMO-SHH signaling is also an important part of a broad variety of neurological processes, including neuronal cell differentiation, proliferation, and survival. Dysregulation of SMO-SHH signaling leads to many physiological changes that lead to neurological disorders such as ASD and contribute to cognitive decline. The aberrant downregulation of SMO-SHH signals contributes to the proteolytic cleavage of GLI (glioma-associated homolog) into GLI3 (repressor), which increases oxidative stress, neuronal excitotoxicity, neuroinflammation, and apoptosis by suppressing target gene expression. We outlined in this review that SMO-SHH deregulation plays a crucial role in the pathogenesis of autism and addresses the current status of SMO-SHH pathway modulators. Additionally, a greater understanding of the SHH signaling pathway is an effort to improve successful treatment for autism and other neurological disorders.

Brief Report: Associations Between Self-injurious Behaviors and Abdominal Pain Among Individuals with ASD-Associated Disruptive Mutations

Self-injurious behaviors (SIB) are elevated in autism spectrum disorder (ASD) and related genetic disorders, but the genetic and biological mechanisms that contribute to SIB in ASD are poorly understood. This study examined rates and predictors of SIB in 112 individuals with disruptive mutations to ASD-risk genes. Current SIB were reported in 30% of participants and associated with poorer cognitive and adaptive skills. History of severe abdominal pain predicted higher rates of SIB and SIB severity after controlling for age and adaptive behavior; individuals with a history of severe abdominal pain were eight times more likely to exhibit SIB than those with no history. Future research is needed to examine associations between genetic risk, pain, and SIB in this population.

Gastrointestinal Symptoms and Feeding Problems and Their Associations with Dietary Interventions, Food Supplement Use, and Behavioral Characteristics in a Sample of Children and Adolescents with Autism Spectrum Disorders

Autism spectrum disorders (ASD) are characterized by impairments in social interaction, communication, and restricted, stereotyped behavior. Gastrointestinal (GI), nutritional, and feeding problems are often reported in ASD. We investigated the prevalence of GI symptoms, food selectivity, and mealtime difficulties, and their associations with dietary interventions, food supplement use, and behavioral characteristics in a sample involving 247 participants with ASD and 267 controls aged 2-18 years. Data were collected by a questionnaire. GI symptoms were observed in 88.9% of children and adolescents with ASD, more often in girls than in boys. High rates of food selectivity (69.1%) and mealtime problems (64.3%) were found. Food supplements were used by 66.7% of individuals, mainly vitamins/minerals, probiotics, and omega-3 fatty acids. In the ASD sample, 21.2% of subjects followed a diet, mostly based on gluten and milk restriction, including individuals exhibiting food selectivity. Frequency of GI symptoms, food selectivity, and mealtime problems correlated weakly, but significantly with behavioral characteristics in the ASD group, but not with food supplement use. The study demonstrated that higher frequency of GI symptoms, food selectivity, and mealtime problems are a common problem in pre-schoolers, schoolchildren, and adolescents with ASD, and together with dietary modification, they are significantly associated with ASD.

The stress polarity signaling (SPS) pathway serves as a marker and a target in the leaky gut barrier: implications in aging and cancer

The gut barrier separates trillions of microbes from the largest immune system in the body; when compromised, a "leaky" gut barrier fuels systemic inflammation, which hastens the progression of chronic diseases. Strategies to detect and repair the leaky gut barrier remain urgent and unmet needs. Recently, a stress-polarity signaling (SPS) pathway has been described in which the metabolic sensor, AMP-kinase acts via its effector, GIV (also known as Girdin) to augment epithelial polarity exclusively under energetic stress and suppresses tumor formation. Using murine and human colon-derived organoids, and enteroid-derived monolayers (EDMs) that are exposed to stressors, we reveal that the SPS-pathway is active in the intestinal epithelium and requires a catalytically active AMP-kinase. Its pharmacologic augmentation resists stress-induced collapse of the epithelium when challenged with microbes or microbial products. In addition, the SPS-pathway is suppressed in the aging gut, and its reactivation in enteroid-derived monolayers reverses aging-associated inflammation and loss of barrier function. It is also silenced during progression of colorectal cancers. These findings reveal the importance of the SPS-pathway in the gut and highlights its therapeutic potential for treating gut barrier dysfunction in aging, cancer, and dysbiosis.

Occurrence, biological properties and potential effects on human health of β-casomorphin 7: Current knowledge and concerns

The genetic variant A1 of bovine β-casein (β-Cn) presents a His residue at a position 67 of the mature protein. This feature makes the Ile⁶⁶-His⁶⁷ bond more vulnerable to enzymatic cleavage, determining the release of the peptide β-Cn f(60-66), named β-casomorphin 7 (BCM7). BCM7 is an opioid-agonist for μ receptors, and it has been hypothesized to be involved in the development of different non-transmissible diseases in humans. In the last decade, studies have provided additional results on the potential health impact of β-Cn A1 and BCM7. These studies, here reviewed, highlighted a relation between the consumption of β-Cn A1 (and its derivative BCM7) and the increase of inflammatory response as well as discomfort at the gastrointestinal level. Conversely, the role of BCM7 and the effects of ingestion of β-Cn A1 on the onset or worsening of other non-transmissible diseases as caused or favored by still need proof of evidence. Overall, the reviewed literature demonstrates that the "β-Cn A1/BCM7 issue" remains an intriguing but not exhaustively explained topic in human nutrition. On this basis, policies in favor of breeding for β-Cn variants not releasing BCM7 and consumption of "A1-like" milk appear not yet sound for a healthier and safer nutrition.

Propionic Acid Induces Gliosis and Neuro-inflammation through Modulation of PTEN/AKT Pathway in Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by glia over-proliferation, neuro-inflammation, perturbed neural circuitry, and gastrointestinal symptoms. The role of gut dys-biosis in ASD is intriguing and should be elucidated. We investigated the effect of Propionic acid (PPA), a short-chain fatty acid (SCFA) and a product of dys-biotic ASD gut, on human neural stem cells (hNSCs) proliferation, differentiation and inflammation. hNSCs proliferated to 66 neuropsheres when exposed to PPA versus 45 in control. The neurosphere diameter also increased at day 10 post PPA treatment to (Mean: 193.47 um ± SEM: 6.673 um) versus (154.16 um ± 9.95 um) in control, p < 0.001. Pre-treatment with β-HB, SCFA receptor inhibitor, hindered neurosphere expansion (p < 0.001). While hNSCs spontaneously differentiated to (48.38% ± 6.08%) neurons (Tubulin-IIIβ positive) and (46.63% ± 2.5%) glia (GFAP positive), PPA treatment drastically shifted differentiation to 80% GFAP cells (p < 0.05). Following 2 mM PPA exposure, TNF-α transcription increased 4.98 fold and the cytokine increased 3.29 fold compared to control (P < 0.001). Likewise, GPR41 (PPA receptor) and pro-survival p-Akt protein were elevated (p < 0.001). PTEN (Akt inhibitor) level decreased to (0.42 ug/ul ± 0.04 ug/ul) at 2 mM PPA compared to (0.83 ug/ul ± 0.09 ug/ul) in control (p < 0.001). PPA at 2 mM decreased neurite outgrowth to (80.70 um ± 5.5 um) compared to (194.93 um ± 19.7 um) in control. Clearly, the data supports a significant role for PPA in modulating hNSC patterning leading to gliosis, disturbed neuro-circuitry, and inflammatory response as seen in ASD.

Intestinal dysmotility in a zebrafish (Danio rerio) shank3a;shank3b mutant model of autism

Background and aims

Autism spectrum disorder (ASD) is currently estimated to affect more than 1% of the world population. For people with ASD, gastrointestinal (GI) distress is a commonly reported but a poorly understood co-occurring symptom. Here, we investigate the physiological basis for GI distress in ASD by studying gut function in a zebrafish model of Phelan-McDermid syndrome (PMS), a condition caused by mutations in the SHANK3 gene.

Methods

To generate a zebrafish model of PMS, we used CRISPR/Cas9 to introduce clinically related C-terminal frameshift mutations in shank3a and shank3b zebrafish paralogues (shank3abΔC). Because PMS is caused by SHANK3 haploinsufficiency, we assessed the digestive tract (DT) structure and function in zebrafish shank3abΔC^+/− heterozygotes. Human SHANK3 mRNA was then used to rescue DT phenotypes in larval zebrafish.

Results

Significantly slower rates of DT peristaltic contractions (p < 0.001) with correspondingly prolonged passage time (p < 0.004) occurred in shank3abΔC^+/− mutants. Rescue injections of mRNA encoding the longest human SHANK3 isoform into shank3abΔC^+/− mutants produced larvae with intestinal bulb emptying similar to wild type (WT), but still deficits in posterior intestinal motility. Serotonin-positive enteroendocrine cells (EECs) were significantly reduced in both shank3abΔC^+/− and shank3abΔC^−/− mutants (p < 0.05) while enteric neuron counts and overall structure of the DT epithelium, including goblet cell number, were unaffected in shank3abΔC^+/− larvae.

Conclusions

Our data and rescue experiments support mutations in SHANK3 as causal for GI transit and motility abnormalities. Reductions in serotonin-positive EECs and serotonin-filled ENS boutons suggest an endocrine/neural component to this dysmotility. This is the first study to date demonstrating DT dysmotility in a zebrafish single gene mutant model of ASD.

Electronic supplementary material

The online version of this article (10.1186/s13229-018-0250-4) contains supplementary material, which is available to authorized users.

Updated View on the Relation of the Pineal Gland to Autism Spectrum Disorders

Identification of the biological features of autism is essential for designing an efficient treatment and for prevention of the disorder. Though the subject of extensive research, the neurophysiological features of autism remain unclear. One of the proposed biological causes of autism is malfunction of the pineal gland and deficiency of its principal hormone, melatonin. The main function of melatonin is to link and synchronize the body's homeostasis processes to the circadian and seasonal rhythms, and to regulate the sleep-wake cycle. Therefore, pineal dysfunction has been implicated based on the common observation of low melatonin levels and sleep disorders associated with autism. In this perspective, we highlight several recent findings that support the hypothesis of pineal gland/melatonin involvement in autism. Another common symptom of autism is abnormal neuroplasticity, such as cortical overgrowth and dendritic spine dysgenesis. Here, we synthesize recent information and speculate on the possibility that this abnormal neuroplasticity is caused by hyperactivity of endogenous N,N-dimethyltryptamine (DMT). The pineal gland was proposed as the source of DMT in the brain and therefore, our assumption is that besides melatonin deficiency, pineal dysfunction might also play a part in the development of autism through abnormal metabolism of DMT. We hope that this manuscript will encourage future research of the DMT hypothesis and reexamination of several observations that were previously attributed to other factors, to see if they could be related to pineal gland/melatonin malfunction. Such research could contribute to the development of autism treatment by exogenous melatonin and monitored light exposure.

Mycobacterium avium subspecies paratuberculosis: A possible causative agent in human morbidity and risk to public health safety

Mycobacterium avium subspecies paratuberculosis is a bacterial parasite and the causative agent of paratuberculosis, a disease predominately found in cattle and sheep. Infection with this microorganism results in substantial farming economic losses and animal morbidity. The link between infection with this pathogen and human disease has been theorised for many years with Crohn's disease being one of many suspected resultant conditions. Mycobacterium avium may be spread from animal to human hosts by water and foodborne transmission routes, where the foodborne route of exposure represents a significant risk for susceptible populations, namely children and the immune-compromised. Following colonisation of the host, the parasitic organism evades the host immune system by use of molecular mimicry, displaying peptide sequences similar to that of the host cells causing a disruption of self-verses non self-recognition. Theoretically, this failure to recognise the invading organism as distinct from host cells may result in numerous autoimmune conditions. Here, the author presents current information assessing the link between numerous diseases states in humans such inflammatory bowel disease, Type 1 diabetes, rheumatoid arthritis, Hashimoto\'s thyroiditis, multiple sclerosis and autism following infection with Mycobacterium avium paratuberculosis. The possibility of zoonotic transmission of the organism and its significant risk to public health safety as a consequence is also discussed.

Serum Cytokine and Growth Factor Levels in Children with Autism Spectrum Disorder

BACKGROUND The immune system may have a role in the pathogenesis of autism spectrum disorder (ASD), including typical and atypical autism. The aim of this study was to determine whether a cytokine and growth factor panel could be identified for the diagnosis and prognosis in children with ASD, including typical and atypical autism. MATERIAL AND METHODS This study included 26 children with ASD (typical or atypical) and 11 of their siblings who did not have ASD. A panel of ten serum cytokines and growth factors were investigated using addressable laser bead assay (ALBIA) and enzyme-linked immunosorbent assay (ELISA) kits. Results were correlated with scores using the Childhood Autism Rating Scale (CARS) and Autism Diagnostic Observation Schedule (ADOS) for the children with ASD and compared with the findings from their siblings without ASD. RESULTS There were no statistically significant differences in serum cytokine and growth factor levels between children with ASD and their siblings. The scores using CARS and ADOS were significantly greater in children with typical autism compared with children with atypical autism as part of the ASD spectrum. Serum levels of cytokines and growth factors showed a positive correlation with CARS and ADOS scores but differed between children with typical and atypical autism and their siblings. CONCLUSIONS The findings of this study showed that serum measurement of appropriately selected panels of cytokines and growth factors might have a role in the diagnosis of ASD.

Salivary biomarkers for the diagnosis and monitoring of neurological diseases

Current research efforts on neurological diseases are focused on identifying novel disease biomarkers to aid in diagnosis, provide accurate prognostic information and monitor disease progression. With advances in detection and quantification methods in genomics, proteomics and metabolomics, saliva has emerged as a good source of samples for detection of disease biomarkers. Obtaining a sample of saliva offers multiple advantages over the currently tested biological fluids as it is a non-invasive, painless and simple procedure that does not require expert training or harbour undesirable side effects for the patients. Here, we review the existing literature on salivary biomarkers and examine their validity in diagnosing and monitoring neurodegenerative and neuropsychiatric disorders such as autism and Alzheimer's, Parkinson's and Huntington's disease. Based on the available research, amyloid beta peptide, tau protein, lactoferrin, alpha-synuclein, DJ-1 protein, chromogranin A, huntingtin protein, DNA methylation disruptions, and micro-RNA profiles provide display a reliable degree of consistency and validity as disease biomarkers.

Are gastrointestinal and sleep problems associated with behavioral symptoms of autism spectrum disorder?

Many children with autism spectrum disorder (ASD) suffer from concurrent medical symptoms, including gastrointestinal (GI) and sleeping problems. However, there is limited information on the correlation between co-morbidities and autistic behavioral symptoms. In this study, we estimated the prevalence of GI and sleep problems in Chinese ASD children, examined the impacts of GI and sleep problems on autistic behavioral symptoms, and investigated the factors associated with GI and sleep problems. The survey included 169 ASD and 172 healthy children. Data regarding demographic characteristics, GI symptoms, sleep disturbances and behavioral symptoms were collected through questionnaires. GI and sleep problems were prevalent in Chinese ASD children. Moreover, ASD children with GI symptoms reported more severe ASD core symptoms than others. Autistic children's GI symptoms were associated with maternal sleep problems during pregnancy, child's 0-6 month food sources and picky eating. ASD children with sleep disturbances had lower performance in daily living skills, social cognition, social communication and intellectual development than ASD children without sleep disturbances. Sleep disturbances were associated with extra nutrient supply during lactation and feeding, and child's picky eating. Autistic children with GI or/and sleep problems may represent clinically relevant subtypes of ASD, for which targeted treatments may be needed.

The stress polarity pathway: AMPK 'GIV'-es protection against metabolic insults

Loss of cell polarity impairs organ development and function; it can also serve as one of the first triggers for oncogenesis. In 2006-2007 two groups simultaneously reported the existence of a special pathway for maintaining epithelial polarity in the face of environmental stressors. In this pathway, AMPK, a key sensor of metabolic stress stabilizes tight junctions, preserves cell polarity, and thereby, maintains epithelial barrier functions. Accumulating evidence since has shown that pharmacologic activation of AMPK by Metformin protects the epithelial barrier against multiple environmental and pathological stressful states and suppresses tumorigenesis. How AMPK protects the epithelium remained unknown until recently Aznar et al. identified GIV/Girdin as a novel effector of AMPK at the cell-cell junctions; phosphorylation of GIV at a single site by AMPK appears to be both necessary and sufficient for strengthening tight junctions and preserving cell polarity and epithelial barrier function in the face of energetic stress. Here we review the fundamentals of this specialized signaling pathway that buttresses cell-cell junctions against stress-induced collapse and discuss its pathophysiologic relevance in the context of a variety of diseases, including cancers, diabetes, aging, and the growing list of beneficial effects of the AMPK-activator, Metformin.

Functional constipation in children: challenges and solutions

This review intends to update what is known about and what is still a challenge in functional constipation (FC) in children regarding epidemiology, pathophysiology, diagnosis, and management. Although FC is a common childhood problem, its global burden remains unknown as data from parts of the world are missing. Another problem is that there is a large variation in prevalence due to differences in study methods and defining age groups. The pathophysiology of FC remains unclear to date but is probably multifactorial. Withholding behavior is likely to be the most important factor in toddlers and young children. Genetics may also play a role since many patients have positive family history, but mutations in genes associated with FC have not been found. Over the past years, different diagnostic criteria for FC in infants and children have been proposed. This year, Rome IV criteria have been released. Compared to Rome III, it eliminates two diagnostic criteria in children under the age of 4 who still wear diapers. Physical examination and taking a thorough medical history are recommended, but other investigations such as abdominal radiography, transabdominal recto-ultrasonography, colonic transit time, rectal biopsies, and colon manometry are not routinely recommended. Regarding treatment, guidelines recommend disimpaction and maintenance therapy with polyethylene glycol (PEG) with or without electrolytes. But experience shows that acceptability, adherence, and tolerance to PEG are still a challenge. Counseling of parents and children about causes of FC is often neglected. Recent studies suggest that behavior therapy added to laxative therapy improves the relief of symptoms. Further homogeneous studies, better-defined outcomes, and studies conducted in primary care are needed.

A Drosophila model of Fragile X syndrome exhibits defects in phagocytosis by innate immune cells

Fragile X syndrome, the most common known monogenic cause of autism, results from the loss of FMR1, a conserved, ubiquitously expressed RNA-binding protein. Recent evidence suggests that Fragile X syndrome and other types of autism are associated with immune system defects. We found that Drosophila melanogaster Fmr1 mutants exhibit increased sensitivity to bacterial infection and decreased phagocytosis of bacteria by systemic immune cells. Using tissue-specific RNAi-mediated knockdown, we showed that Fmr1 plays a cell-autonomous role in the phagocytosis of bacteria. Fmr1 mutants also exhibit delays in two processes that require phagocytosis by glial cells, the immune cells in the brain: neuronal clearance after injury in adults and the development of the mushroom body, a brain structure required for learning and memory. Delayed neuronal clearance is associated with reduced recruitment of activated glia to the site of injury. These results suggest a previously unrecognized role for Fmr1 in regulating the activation of phagocytic immune cells both in the body and the brain.

Pediatric Traumatic Brain Injury and Autism: Elucidating Shared Mechanisms

Pediatric traumatic brain injury (TBI) and autism spectrum disorder (ASD) are two serious conditions that affect youth. Recent data, both preclinical and clinical, show that pediatric TBI and ASD share not only similar symptoms but also some of the same biologic mechanisms that cause these symptoms. Prominent symptoms for both disorders include gastrointestinal problems, learning difficulties, seizures, and sensory processing disruption. In this review, we highlight some of these shared mechanisms in order to discuss potential treatment options that might be applied for each condition. We discuss potential therapeutic and pharmacologic options as well as potential novel drug targets. Furthermore, we highlight advances in understanding of brain circuitry that is being propelled by improved imaging modalities. Going forward, advanced imaging will help in diagnosis and treatment planning strategies for pediatric patients. Lessons from each field can be applied to design better and more rigorous trials that can be used to improve guidelines for pediatric patients suffering from TBI or ASD.

Fatal case of acute gastroenteritis with multiple viral coinfections

We report a fatal case of acute gastroenteritis in a child with autism spectrum disorder. Multiple viral coinfections were detected by PCR in the patient’s stool and digestive biopsy specimens. As viral detection is not necessarily associated with symptomatic disease, a semi-quantitative approach using cycle treshold values was proposed for the clinical interpretation of PCR. We discuss whether concomitant viral infections could be a risk factor for severe outcome in gastroenteritis cases. Individual risk factors are also addressed.

Salivary proteomics and biomarkers in neurology and psychiatry

Biomarkers are greatly needed in the fields of neurology and psychiatry, to provide objective and earlier diagnoses of CNS conditions. Proteomics and other omics MS-based technologies are tools currently being utilized in much recent CNS research. Saliva is an interesting alternative biomaterial for the proteomic study of CNS disorders, with several advantages. Collection is noninvasive and saliva has many proteins. It is easier to collect than blood and can be collected by professionals without formal medical training. For psychiatric and neurological patients, supplying a saliva sample is less anxiety-provoking than providing a blood sample, and is less embarrassing than producing a urine specimen. The use of saliva as a biomaterial has been researched for the diagnosis of and greater understanding of several CNS conditions, including neurodegenerative diseases, autism, and depression. Salivary biomarkers could be used to rule out nonpsychiatric conditions that are often mistaken for psychiatric/neurological conditions, such as fibromyalgia, and potentially to assess cognitive ability in individuals with compromised brain function. As MS and omics technology advances, the sensitivity and utility of assessing CNS conditions using distal human biomaterials such as saliva is becoming increasingly possible.

Zinc in gut-brain interaction in autism and neurological disorders

A growing amount of research indicates that abnormalities in the gastrointestinal (GI) system during development might be a common factor in multiple neurological disorders and might be responsible for some of the shared comorbidities seen among these diseases. For example, many patients with Autism Spectrum Disorder (ASD) have symptoms associated with GI disorders. Maternal zinc status may be an important factor given the multifaceted effect of zinc on gut development and morphology in the offspring. Zinc status influences and is influenced by multiple factors and an interdependence of prenatal and early life stress, immune system abnormalities, impaired GI functions, and zinc deficiency can be hypothesized. In line with this, systemic inflammatory events and prenatal stress have been reported to increase the risk for ASD. Thus, here, we will review the current literature on the role of zinc in gut formation, a possible link between gut and brain development in ASD and other neurological disorders with shared comorbidities, and tie in possible effects on the immune system. Based on these data, we present a novel model outlining how alterations in the maternal zinc status might pathologically impact the offspring leading to impairments in brain functions later in life.

Reduced levels of plasma polyunsaturated fatty acids and serum carnitine in autistic children: relation to gastrointestinal manifestations

BACKGROUND

Gastrointestinal (GI) manifestations are common in autistic children. Polyunsaturated fatty acids (PUFAs) and carnitine are anti-inflammatory molecules and their deficiency may result in GI inflammation. The relationship between the increased frequency of GI manifestations and reduced levels of PUFAs and carnitine was not previously investigated in autistic patients. This study was the first to investigate plasma levels of PUFAs and serum carnitine in relation to GI manifestations in autistic children.

METHODS

Plasma levels of PUFAs (including linoleic, alphalinolenic, arachidonic "AA" and docosahexaenoic "DHA" acids) and serum carnitine were measured in 100 autistic children and 100 healthy-matched children.

RESULTS

Reduced levels of serum carnitine and plasma DHA, AA, linolenic and linoleic acids were found in 66%, 62%, 60%, 43% and 38%, respectively of autistic children. On the other hand, 54% of autistic patients had elevated ω6/ω3 ratio. Autistic patients with GI manifestations (48%) had significantly decreased levels of serum carnitine and plasma DHA than patients without such manifestations. In addition, autistic patients with GI manifestations had significantly increased percentage of reduced serum carnitine (91.7%) and plasma DHA levels (87.5%) than patients without such manifestations (42.3% and 38.5%, respectively), (P < 0.001 and P < 0.001%, respectively).

CONCLUSIONS

Reduced levels of plasma DHA and serum carnitine levels may be associated with the GI problems in some autistic patients. However, this is an initial report, studies are recommended to invesigate whether reduced levels of carnitine and DHA are a mere association or have a pathogenic role in GI problems in autistic patients.