Can bronchoscopic airway anatomy be an indicator of autism?

Hypothesis: 2 Major Environmental and Pharmaceutical Factors-Acetaminophen Exposure and Gastrointestinal Overgrowth of Clostridia Bacteria Induced By Ingestion of Glyphosate-Contaminated Foods-Dysregulate the Developmental Protein Sonic Hedgehog and Are Major Causes of Autism

Epidemiological studies have found 2 significant factors associated with the increased incidence of autism spectrum disorder (ASD): the increased use of acetaminophen in the 1970s when this drug largely replaced the use of aspirin for many patients because of a fear of Reye syndrome, and the agricultural use in the 1990s of the herbicide glyphosate on crops that were genetically modified (GM) to tolerate glyphosate. The incidence of autism in the United States, where acetaminophen is widely available, is more than 1000 times greater than in Cuba, where acetaminophen is available only by prescription. Metabolites of both glyphosate and acetaminophen likely alter the function of the developmental protein sonic hedgehog (SHH). Glyphosate likely affects SHH indirectly by decreasing the beneficial flora of the gastrointestinal tract and increasing pathogenic Clostridia bacteria, which are resistant to glyphosate. The marked increase of certain Clostridia species caused by glyphosate results in Clostridia production of large amounts of 3-(3-hydroxyphenyl)-3-hydroxypropionate (HPHPA) and 4-cresol (p-cresol). The 4-cresol metabolite 4-methyl-o-hydroquinone and the acetaminophen metabolite N-acetyl-p-benzoquinone imine (NAPQI) likely react with the sulfhydryl group of the N-terminal cysteine of SHH, blocking the function of this critical amino acid required for the activation of SHH. HPHPA and 4-cresol also inhibit dopamine β-hydroxylase, resulting in overproduction of dopamine and its toxic metabolites, such as aminochrome, that cause biochemical damage to mitochondria and structural proteins in brain cells. Elevated amounts of these Clostridia products in body fluids in people with autism and in animals with autistic signs have been documented in laboratories throughout the world. The synthesis of the HPHPA molecule in extremely large quantities depletes the body of free coenzyme A, which is needed for the palmitoylation of SHH. SHH covalently coupled to palmitic acid is 30 times more active than SHH without palmitic acid. These possible modifications of SHH help to explain the significantly altered quantities of SHH in the blood serum of patients with autism. The severity of autism is related to the degree of SHH abnormality. The spread of pathogenic Clostridia worldwide from soil to food animals to humans, which may be promoted by glyphosate use, is a great public health concern, not only for autism but perhaps for all the neuropsychiatric diseases that appear to be related to gastrointestinal Clostridia overgrowth These diseases include seizures, tremors, tic disorders, Parkinson disease, chronic fatigue syndrome, obsessive compulsive disorder, schizophrenia, bipolar and unipolar depression, ADHD, and anorexia nervosa.

The influence of asthma on neuroinflammation and neurodevelopment: From epidemiology to basic models

Asthma is a highly heterogeneous inflammatory disease that can have a significant effect on both the respiratory system and central nervous system. Population based studies and animal models have found asthma to be comorbid with a number of neurological conditions, including depression, anxiety, and neurodevelopmental disorders. In addition, maternal asthma during pregnancy has been associated with neurodevelopmental disorders in the offspring, such as autism spectrum disorders and attention deficit hyperactivity disorder. In this article, we review the most current epidemiological studies of asthma that identify links to neurological conditions, both as it relates to individuals that suffer from asthma and the impacts asthma during pregnancy may have on offspring neurodevelopment. We also discuss the relevant animal models investigating these links, address the gaps in knowledge, and explore the potential future directions in this field.

Can lung airway geometry be used to predict autism? A preliminary machine learning-based study

The goal of this study is to assess the feasibility of airway geometry as a biomarker for autism spectrum disorder (ASD). Chest computed tomography images of children with a documented diagnosis of ASD as well as healthy controls were identified retrospectively. Fifty-four scans were obtained for analysis, including 31 ASD cases and 23 controls. A feature selection and classification procedure using principal component analysis and support vector machine achieved a peak cross validation accuracy of nearly 89% using a feature set of eight airway branching angles. Sensitivity was 94%, but specificity was only 78%. The results suggest a measurable difference in airway branching angles between children with ASD and the control population.

De novo network analysis reveals autism causal genes and developmental links to co-occurring traits

Autism is a complex neurodevelopmental condition that manifests in various ways. Autism is often accompanied by other conditions, such as attention-deficit/hyperactivity disorder and schizophrenia, which can complicate diagnosis and management. Although research has investigated the role of specific genes in autism, their relationship with co-occurring traits is not fully understood. To address this, we conducted a two-sample Mendelian randomisation analysis and identified four genes located at the 17q21.31 locus that are putatively causal for autism in fetal cortical tissue (LINC02210, LRRC37A4P, RP11-259G18.1, and RP11-798G7.6). LINC02210 was also identified as putatively causal for autism in adult cortical tissue. By integrating data from expression quantitative trait loci, genes and protein interactions, we identified that the 17q21.31 locus contributes to the intersection between autism and other neurological traits in fetal cortical tissue. We also identified a distinct cluster of co-occurring traits, including cognition and worry, linked to the genetic loci at 3p21.1. Our findings provide insights into the relationship between autism and co-occurring traits, which could be used to develop predictive models for more accurate diagnosis and better clinical management.

Distinctive prosodic features of people with autism spectrum disorder: a systematic review and meta-analysis study

In this systematic review, we analyzed and evaluated the findings of studies on prosodic features of vocal productions of people with autism spectrum disorder (ASD) in order to recognize the statistically significant, most confirmed and reliable prosodic differences distinguishing people with ASD from typically developing individuals. Using suitable keywords, three major databases including Web of Science, PubMed and Scopus, were searched. The results for prosodic features such as mean pitch, pitch range and variability, speech rate, intensity and voice duration were extracted from eligible studies. The pooled standard mean difference between ASD and control groups was extracted or calculated. Using I2 statistic and Cochrane Q-test, between-study heterogeneity was evaluated. Furthermore, publication bias was assessed using funnel plot and its significance was evaluated using Egger's and Begg's tests. Thirty-nine eligible studies were retrieved (including 910 and 850 participants for ASD and control groups, respectively). This systematic review and meta-analysis showed that ASD group members had a significantly larger mean pitch (SMD =  - 0.4, 95% CI [- 0.70, - 0.10]), larger pitch range (SMD =  - 0.78, 95% CI [- 1.34, - 0.21]), longer voice duration (SMD =  - 0.43, 95% CI [- 0.72, - 0.15]), and larger pitch variability (SMD = - 0.46, 95% CI [- 0.84, - 0.08]), compared with typically developing control group. However, no significant differences in pitch standard deviation, voice intensity and speech rate were found between groups. Chronological age of participants and voice elicitation tasks were two sources of between-study heterogeneity. Furthermore, no publication bias was observed during analyses (p > 0.05). Mean pitch, pitch range, pitch variability and voice duration were recognized as the prosodic features reliably distinguishing people with ASD from TD individuals.

The "Connectivome Theory": A New Model to Understand Autism Spectrum Disorders

The classical approach to autism spectrum disorders (ASD) is often limited to considering their neuro-functional aspects. However, recent scientific literature has shown that ASDs also affect many body systems and apparatuses such as the immune system, the sensory-motor system, and the gut-brain axis. The connective tissue, a common thread linking all these structures, may have a pathogenetic role in the multisystem involvement of ASD. Depending on its different anatomical sites, the connective tissue performs functions of connection and support; furthermore, it acts as a barrier between the external and internal environments, regulating the interchange between the two and performing immunological surveillance. The connective tissue shares a close relationship with the central nervous system, the musculoskeletal system and the immune system. Alterations in brain connectivity are common to various developmental disorders, including ASD, and for this reason here we put forward the hypothesis that alterations in the physiological activity of microglia could be implicated in the pathogenesis of ASD. Also, muscle hypotonia is likely to clinically correlate with an altered sensoriality and, in fact, discomfort or early muscle fatigue are often reported in ASDs. Furthermore, patients with ASD often suffer from intestinal dysfunctions, malabsorption and leaky gut syndrome, all phenomena that may be linked to reduced intestinal connectivity. In addition, at the cutaneous and subcutaneous levels, ASDs show a greater predisposition to inflammatory events due to the lack of adequate release of anti-inflammatory mediators. Alveolar-capillary dysfunctions have also been observed in ASD, most frequently interstitial inflammations, immune-mediated forms of allergic asthma, and bronchial hyper-reactivity. Therefore, in autism, altered connectivity can result in phenomena of altered sensitivity to environmental stimuli. The following interpretative model, that we define as the "connectivome theory," considers the alterations in connective elements of common mesodermal origin located in the various organs and apparatuses and entails the evaluation and interpretation of ASDs through also highlighting somatic elements. We believe that this broader approach could be helpful for a more accurate analysis, as it is able to enrich clinical evaluation and define more multidisciplinary and personalized interventions.

Opposite Expression Patterns of Spry3 and p75NTR in Cerebellar Vermis Suggest a Male-Specific Mechanism of Autism Pathogenesis

Autism is a genetically complex neurobehavioral disorder with a population prevalence of more than 1%. Cerebellar abnormalities, including Purkinje cell deficits in the vermis, are consistently reported, and rodent models of cerebellar dysfunction exhibit features analogous to human autism. We previously analyzed the regulation and expression of the pseudoautosomal region 2 gene SPRY3, which is adjacent to X chromosome-linked TMLHE, a known autism susceptibility gene. SPRY3 is a regulator of branching morphogenesis and is strongly expressed in Purkinje cells. We previously showed that mouse Spry3 is not expressed in cerebellar vermis lobules VI-VII and X, regions which exhibit significant Purkinje cell loss or abnormalities in autism. However, these lobules have relatively high expression of p75NTR, which encodes a neurotrophin receptor implicated in autism. We propose a mechanism whereby inappropriate SPRY3 expression in these lobules could interact with TrkB and p75NTR signaling pathways resulting in Purkinje cell pathology. We report preliminary characterization of X and Y chromosome-linked regulatory sequences upstream of SPRY3, which are polymorphic in the general population. We suggest that an OREG-annotated region on chromosome Yq12 ∼60 kb from SPRY3 acts as a silencer of Y-linked SPRY3 expression. Deletion of a β-satellite repeat, or alterations in chromatin structure in this region due to trans-acting factors, could affect the proposed silencing function, leading to reactivation and inappropriate expression of Y-linked SPRY3. This proposed male-specific mechanism could contribute to the male bias in autism prevalence.

How does autism spectrum disorder affect the risk and severity of childhood asthma?

BACKGROUND

Autism spectrum disorder (ASD) and asthma are among the most common chronic disorders in childhood. Both are associated with altered immune regulation and share several risk factors. The effects of ASD on risk for later asthma and asthma severity remain unclear.

OBJECTIVE

To determine whether ASD in children increases the risk of incident asthma and worsens asthma severity.

METHODS

We performed 2 distinct analytic designs (case-control and retrospective longitudinal cohort) using a multistate electronic health records database to assess the odds of new asthma and asthma severity among children with ASD. In both designs, children with ASD were matched with children without ASD according to sex, age, race, ethnicity, location, and insurance status. Pulmonary function, controller medication prescriptions, asthma exacerbations, and asthma-related hospitalizations were collected. The effects of ASD on asthma risk and severity were assessed using multivariable linear and logistic regression.

RESULTS

Among children with asthma, ASD was associated with reduced exacerbations (odds ratio [OR], 0.71; 95% confidence interval [CI], 0.54-0.92), better forced expiratory volume in 1 second/forced vital capacity ratio (0.876 vs 0.841, P < .001), and lower odds of airflow obstruction (OR, 0.53; 95% CI, 0.31-0.90) but had higher odds of asthma controller prescription (OR, 2.18; 95% CI, 1.62-2.93). In a longitudinal analysis of children without asthma, ASD was found to be protective for new asthma (OR, 0.44; 95% CI, 0.26-0.74).

CONCLUSION

Among children with asthma, concomitant ASD is associated with better asthma-related outcomes but a higher controller treatment burden. In addition, our data did not support ASD as a risk factor for incident asthma.

Fetal calcium regulates branching morphogenesis in the developing human and mouse lung: involvement of voltage-gated calcium channels

Airway branching morphogenesis in utero is essential for optimal postnatal lung function. In the fetus, branching morphogenesis occurs during the pseudoglandular stage (weeks 9–17 of human gestation, embryonic days (E)11.5–16.5 in mouse) in a hypercalcaemic environment (∼1.7 in the fetus vs. ∼1.1–1.3 mM for an adult). Previously we have shown that fetal hypercalcemia exerts an inhibitory brake on branching morphogenesis via the calcium-sensing receptor. In addition, earlier studies have shown that nifedipine, a selective blocker of L-type voltage-gated Ca²⁺ channels (VGCC), inhibits fetal lung growth, suggesting a role for VGCC in lung development. The aim of this work was to investigate the expression of VGCC in the pseudoglandular human and mouse lung, and their role in branching morphogenesis. Expression of L-type (Ca_V1.2 and Ca_V1.3), P/Q type (Ca_V2.1), N-type (Ca_V2.2), R-type (Ca_V2.3), and T-type (Ca_V3.2 and Ca_V3.3) VGCC was investigated in paraffin sections from week 9 human fetal lungs and E12.5 mouse embryos. Here we show, for the first time, that Ca_v1.2 and Ca_v1.3 are expressed in both the smooth muscle and epithelium of the developing human and mouse lung. Additionally, Ca_v2.3 was expressed in the lung epithelium of both species. Incubating E12.5 mouse lung rudiments in the presence of nifedipine doubled the amount of branching, an effect which was partly mimicked by the Ca_v2.3 inhibitor, SNX-482. Direct measurements of changes in epithelial cell membrane potential, using the voltage-sensitive fluorescent dye DiSBAC₂(3), demonstrated that cyclic depolarisations occur within the developing epithelium and coincide with rhythmic occlusions of the lumen, driven by the naturally occurring airway peristalsis. We conclude that VGCC are expressed and functional in the fetal human and mouse lung, where they play a role in branching morphogenesis. Furthermore, rhythmic epithelial depolarisations evoked by airway peristalsis would allow for branching to match growth and distension within the developing lung.

δ ENaC: a novel divergent amiloride-inhibitable sodium channel

The fourth subunit of the epithelial sodium channel, termed delta subunit (δ ENaC), was cloned in human and monkey. Increasing evidence shows that this unique subunit and its splice variants exhibit biophysical and pharmacological properties that are divergent from those of α ENaC channels. The widespread distribution of epithelial sodium channels in both epithelial and nonepithelial tissues implies a range of physiological functions. The altered expression of SCNN1D is associated with numerous pathological conditions. Genetic studies link SCNN1D deficiency with rare genetic diseases with developmental and functional disorders in the brain, heart, and respiratory systems. Here, we review the progress of research on δ ENaC in genomics, biophysics, proteomics, physiology, pharmacology, and clinical medicine.