Proposed toxic and hypoxic impairment of a brainstem locus in autism

HIF-1 α may play a role in late pregnancy hypoxia-induced autism-like behaviors in offspring rats

Autism spectrum disorder (ASD) is a neurodevelopmental disorder that can be caused by various factors. The present study aimed to determine whether prenatal hypoxia can lead to ASD and the role of hypoxia-inducible factor-1α (HIF-1α) in this process. We constructed a prenatal hypoxia model of pregnant rats by piping nitrogen and oxygen mixed gas, with an oxygen concentration of 10 ± 0.5 %, into the self-made hypoxia chamber. Rats were subjected to different extents of hypoxia treatments at different points during pregnancy. The results showed that hypoxia for 6 h on the 17th gestation day is most likely to lead to autistic behavior in offspring rats, including social deficits, repetitive behaviors, and impaired learning and memory. The mRNA expression level of TNF-α also increased in hypoxia-induced autism group and valproic acid (VPA) group. Western blotting analysis showed increased levels of hypoxia inducible factor 1 alpha (HIF-1α) and decreased levels of phosphatase and tensin homolog (PTEN) in the hypoxic-induced autism group. Meanwhile, N-methyl d-aspartate receptor subtype 2 (NR2A) and glutamate ionotropic receptor AMPA type subunit 2 (GluR2) were upregulated in the hypoxic-induced autism group. HIF-1α might play a role in hypoxia-caused autism-like behavior and its regulatory effect is likely to be achieved by regulating synaptic plasticity.

Association of Autism with Maternal Infections, Perinatal and Other Risk Factors: A Case-Control Study

This case-control study explores the association between pregnancy/birth complications and other factors with Autism Spectrum Disorder (ASD) in Lebanese subjects aged 2-18 years. Researchers interviewed 136 ASD cases from the American University of Beirut Medical Center Special Kids Clinic, and 178 controls selected by systematic digit dialing in the Greater-Beirut area. Male gender (Adjusted Odds Ratio [95% CI]: 3.9 [2.2-7.0]); postpartum feeding difficulties (2.5 [1.2-5.4]); maternal infections/complications during pregnancy (2.9 [1.5-5.5], 2.1 [1.1-3.9]); consanguinity (2.5 [1.0-6.0]); family history of psychiatric disorders (2.2 [1.1-4.4]) were risk factors for ASD. Being born first/second (0.52 [0.28-0.95]) and maternal psychological support during pregnancy (0.49 [0.27-0.89]) were negatively associated with ASD. Identifying ASD correlates is crucial for instigating timely screening and subsequent early intervention.

Methylation-reprogrammed Wnt/β-catenin signalling mediated prenatal hypoxia-induced brain injury in foetal and offspring rats

Prenatal hypoxia (PH) is a common pregnancy complication, harmful to brain development. This study investigated whether and how PH affected Wnt pathway in the brain. Pregnant rats were exposed to hypoxia (10.5% O₂) or normoxia (21% O₂; Control). Foetal brain weight and body weight were decreased in the PH group, the ratio of brain weight to body weight was increased significantly. Prenatal hypoxia increased mRNA expression of Wnt3a, Wnt7a, Wnt7b and Fzd4, but not Lrp6. Activated β‐catenin protein and Fosl1 expression were also significantly up‐regulated. Increased Hif1a expression was found in the PH group associated with the higher Wnt signalling. Among 5 members of the Sfrp family, Sfrp4 was down‐regulated. In the methylation‐regulating genes, higher mRNA expressions of Dnmt1 and Dnmt3b were found in the PH group. Sodium bisulphite and sequencing revealed hyper‐methylation in the promoter region of Sfrp4 gene in the foetal brain, accounting for its decreased expression and contributing to the activation of the Wnt‐Catenin signalling. The study of PC12 cells treated with 5‐aza further approved that decreased methylation could result in the higher Sfrp4 expression. In the offspring hippocampus, protein levels of Hif1a and mRNA expression of Sfrp4 were unchanged, whereas Wnt signal pathway was inhibited. The data demonstrated that PH activated the Wnt pathway in the foetal brain, related to the hyper‐methylation of Sfrp4 as well as Hif1a signalling. Activated Wnt signalling might play acute protective roles to the foetal brain in response to hypoxia, also would result in disadvantageous influence on the offspring in long‐term.

Ellagic acid improves electrocardiogram waves and blood pressure against global cerebral ischemia rat experimental models

BACKGROUND

Global cerebral ischemia (GCIR) arises in patients that are shown a variety of clinical difficulty including cardiac arrest, asphyxia, and shock. In spite of advances in understanding of the brain, ischemia and protective effects to improve ischemic injury still remain unknown. The aim of our study was to investigate the effect of ellagic acid (EA) pretreatment in the rat models of global cerebral ischemia reperfusion.

METHODS

This experimental study was conducted in 2014 at the Physiology Research Center of the Ahvaz Jundishapur University of Medical Sciences in Ahvaz, Iran. Adult male Wistar rats (250-300 g) were used in this study. GCIR was induced by bilateral vertebral and common carotid arteries occlusion (4-VO). 32 rats were divided randomly to four groups: 1) So (Sham) received normal saline as vehicle of EA, 2) EA, 3) normal saline + GCIR, and 4) EA + GCIR. After anesthesia (a mix of xylazine and ketamine), animal subjected to 20 minutes of ischemia followed by 30 minutes of reperfusion in related groups. EA (100 mg/kg, dissolved in normal saline) or 1.5 ml/kg normal saline was administered (gavage, 10 days) to the related groups. EEG was recorded from NTS in GCIR treated groups.

RESULTS

Present data showed that: 1) EEG in GCIR treated groups was flattened; 2) Blood pressure, voltage of QRS and P-R interval were reduced significantly in the ischemic groups compared to before ischemia, and pretreatment with EA prevented this reduction; and 3) MDA level and heart rate was increased by GCIR and pretreatment with EA reduced MDA level and restored the HR to normal level.

CONCLUSION

Results indicate that global cerebral ischemia-reperfusion impairs certain heart functions and ellagic acid as an antioxidant can restore these parameters. The results of this study suggest the possible utility of ellagic acid in patients with brain stroke.