Is fever a predictive factor in the autism spectrum disorders?

Randomized crossover feasibility trial of helminthic Trichuris suis ova versus placebo for repetitive behaviors in adult autism spectrum disorder

Objectives: Inflammatory mechanisms are implicated in the aetiology of autism spectrum disorder (ASD), and use of the immunomodulator Trichuris suis Ova (TSO) is a novel treatment approach. This pilot study determined the effect sizes for TSO versus placebo on repetitive behaviours, irritability and global functioning in adults with ASD.Methods: A 28-week double-blind, randomised two-period crossover study of TSO versus placebo in ten ASD adults, aged 17-35, was completed, with a 4-week washout between each 12-week period at Montefiore Medical Center, Albert Einstein College of Medicine. Subjects with ASD, history of seasonal, medication or food allergies, Y-BOCS ≥6 and IQ ≥70 received 2,500 TSO ova or matching placebo every 2 weeks of each 12-week period.Results: Large effect sizes for improvement in repetitive behaviours (d = 1.0), restricted interests (d = 0.82), rigidity (d = 0.79) and irritability (d = 0.78) were observed after 12 weeks of treatment. No changes were observed in the social-communication domain. Differences between treatment groups did not reach statistical significance. TSO had only minimal, non-serious side effects.Conclusions: This proof-of-concept study demonstrates the feasibility of TSO for the treatment of ASD, including a favourable safety profile, and moderate to large effect sizes for reducing repetitive behaviours and irritability.Clinicaltrials.gov: NCT01040221.

Children with autism spectrum disorder who improve with fever: Insights from the Simons Simplex Collection

Literature indicates that some children with ASD may show behavioral improvements during fever; however, little is known about the behavioral profiles of these children. This study aims to (a) investigate the subset of children who show parent-reported behavioral improvements associated with fever and (b) compare the demographic, behavioral, and genetic characteristics of this subset of children to children whose parents report no change during fever. Parents of 2,152 children from the Simons Simplex Collection provided information about whether and in which areas their child improved during fever. Children were randomly assigned into discovery or replication samples. In discovery analyses, children who reportedly improved with fever (Improve Group) were compared to those who reportedly did not improve (No Improve Group) on demographics, medical history, ASD symptoms, adaptive skills, and presence of de novo ASD-associated mutations. Significant and marginal results from discovery analyses were tested in the replication sample. Parent reports of 17% of children indicated improvements during fever across a range of domains. Discovery and replication analyses revealed that the Improve Group had significantly lower non-verbal cognitive skills (NVIQ) and language levels and more repetitive behaviors. Groups did not differ on demographic variables, parent-report of current ASD symptoms or the presence of de novo mutations. Understanding the profiles of children who improve during episodes of fever may provide insights into innovative treatments for ASD. Autism Res 2018, 11: 175-184. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.

LAY SUMMARY

This study explored characteristics of children with ASD who are reported to improve during fever. Parents of 17% of children with ASD report improvements across a range of domains during fever including cognition, communication, repetitive behaviors, social interaction, and behavior. Children who are reported to improve during fever have significantly lower non-verbal cognitive skills and language levels and more repetitive behaviors. Understanding the profiles of children who improve during episodes of fever may provide insights into new treatments for ASD.

Does environmental exposure to the greenhouse gas, N2O, contribute to etiological factors in neurodevelopmental disorders? A mini-review of the evidence

BACKGROUND

Neurodevelopmental disorders are increasing in prevalence worldwide. Previous work suggests that exposure to the environmental air pollutant and greenhouse gas - nitrous oxide (N₂O) - may be an etiological factor in neurodevelopmental disorders through the targeting of several neural correlates.

METHODOLOGY

While a number of recent systematic reviews have addressed the role of general anesthesia in the surgical setting and neurodevelopmental outcomes, a narrative mini-review was conducted to first define and characterize the relevant variables (i.e., N₂O, attention-deficit hyperactivity disorder [ADHD] and autism spectrum disorders [ASD]) and their potential interactions into a coherent, hypothesis-generating work. The narrative mini-review merges basic principles in environmental science, anesthesiology, and psychiatry to more fully develop the novel hypotheses that neurodevelopmental impairment found in conditions like ADHD and ASD may be due to exposure to the increasing air pollutant, N₂O.

RESULTS

The results of the present mini-review indicate that exposure to N₂O, even at non-toxic doses, may modulate central neurotransmission and target many neural substrates directly implicated in neurodevelopmental disorders, including the glutamatergic, opioidergic, cholinergic, and dopaminergic systems. Epidemiological studies also indicate that early and repeated exposure to general anesthesia, including N₂O, may contribute to later adverse neurodevelopmental outcomes in children.

CONCLUSIONS

The current evidence and subsequent hypotheses suggest that a renewed interest be taken in the toxicological assessment of environmental N₂O exposure using validated biomarkers and psychiatric endpoints. Given the relevance of N₂O as a greenhouse gas, societies may also wish to engage in a more robust monitoring and reporting of N₂O levels in the environment for climactic benefit as well.

Cyclic ADP-Ribose and Heat Regulate Oxytocin Release via CD38 and TRPM2 in the Hypothalamus during Social or Psychological Stress in Mice

Hypothalamic oxytocin (OT) is released into the brain by cyclic ADP-ribose (cADPR) with or without depolarizing stimulation. Previously, we showed that the intracellular free calcium concentration ([Ca²⁺]_i) that seems to trigger OT release can be elevated by β-NAD⁺, cADPR, and ADP in mouse oxytocinergic neurons. As these β-NAD⁺ metabolites activate warm-sensitive TRPM2 cation channels, when the incubation temperature is increased, the [Ca²⁺]_i in hypothalamic neurons is elevated. However, it has not been determined whether OT release is facilitated by heat in vitro or hyperthermia in vivo in combination with cADPR. Furthermore, it has not been examined whether CD38 and TRPM2 exert their functions on OT release during stress or stress-induced hyperthermia in relation to the anxiolytic roles and social behaviors of OT under stress conditions. Here, we report that OT release from the isolated hypothalami of male mice in culture was enhanced by extracellular application of cADPR or increasing the incubation temperature from 35°C to 38.5°C, and simultaneous stimulation showed a greater effect. This release was inhibited by a cADPR-dependent ryanodine receptor inhibitor and a nonspecific TRPM2 inhibitor. The facilitated release by heat and cADPR was suppressed in the hypothalamus isolated from CD38 knockout mice and CD38- or TRPM2-knockdown mice. In the course of these experiments, we noted that OT release differed markedly between individual mice under stress with group housing. That is, when male mice received cage-switch stress and eliminated due to their social subclass, significantly higher levels of OT release were found in subordinates compared with ordinates. In mice exposed to anxiety stress in an open field, the cerebrospinal fluid (CSF) OT level increased transiently at 5 min after exposure, and the rectal temperature also increased from 36.6°C to 37.8°C. OT levels in the CSF of mice with lipopolysaccharide-induced fever (+0.8°C) were higher than those of control mice. The TRPM2 mRNA levels and immunoreactivities increased in the subordinate group with cage-switch stress. These results showed that cADPR/CD38 and heat/TRPM2 are co-regulators of OT secretion and suggested that CD38 and TRPM2 are potential therapeutic targets for OT release in psychiatric diseases caused by social stress.