Age-Dependent Effects of Acute Alcohol Administration in the Hippocampal Phosphoproteome

General anesthesia in early childhood and possible association with autism: a population-based matched cohort study

BACKGROUND

In experimental animal studies, exposure to general anesthesia in early childhood may results in changes in infant brain morphology and behavior, potentially leading to the development of autistic behaviors in the long-term. However, in clinical studies the role of exposure to general anesthesia in early childhood and the risk of autism is unknown.

METHODS

This is a population-based cohort study including all children aged 0-5 years of age exposed to general anesthesia between 2001 and 2014 and a corresponding matched population without such an exposure. Propensity score calculation was based on 49 variables (including age of parents, malformations, APGAR Score, and family income, among others). Quasi-Poisson regression was used to estimate risk ratios (RRs) with 95% confidence intervals (CIs) for the association between exposure to general anesthesia and autism or autism spectrum disorder.

RESULTS

In total, 401,750 children exposed to general anesthesia were compared with 1,187,796 unexposed individuals. Autism or autism spectrum disorder were more common in the children exposed to general anesthesia as compared to unexposed children (1.65% and 0.98%, respectively, P<0.01). There was a statistically significant higher risk of autism or autism spectrum disorder in children exposed to general anesthesia as compared to unexposed children also after propensity score adjustment (RR 1.62, 95% CI: 1.57-1.67).

CONCLUSIONS

Exposure to general anesthesia in early childhood was associated with an increased risk of autism or autism spectrum disorder. Future studies are needed to asses if general anesthesia may cause autism or if the association is due to other factors.

Proteome-Wide Analysis of the Hippocampus in Adult Mice with Learning and Memory Impairment Caused by Chronic Ethanol Exposure

Alcohol consumption may cause various impairments in the brain. The hippocampus is particularly vulnerable to alcohol exposure, which may cause learning and memory deficits. Recently, proteomics analysis has become a popular approach to explore the pathogenesis of various diseases. The present study was conducted to investigate protein expression alteration in the hippocampus and to identify the molecular mechanisms underlying ethanol-induced learning and memory impairments. Mouse models of chronic ethanol intoxication were established by intragastrical administration for 28 consecutive days, and hippocampal neuronal damage was assessed by Nissl staining. Recognition memory was evaluated by Novel object recognition and Morris water maze tests, and hippocampus tissues were collected for label-free quantitative proteomics and analyzed using bioinformatics methods. Our study showed that chronic ethanol exposure prompted marked changes in protein expression in the hippocampus. We identified 32 differentially expressed proteins, of which 21 were upregulated and 11 downregulated. Gene Ontology analysis suggested that the identified differentially proteins were mainly involved in cytoskeleton and signal transduction mechanisms. Further verification using Western blotting and real-time quantitative PCR revealed that the hippocampal CTSL (cathepsin L), and PVALB (Parvalbumin) showed strongest expression changes, the latter being specifically expressed in GABAergic interneurons. These two proteins might serve as candidate protein biomarkers, providing new prospects for the diagnosis and treatment of ethanol-induced learning and memory disorders.

Effects of Intermittent versus Chronic-Moderate Ethanol Administration during Adolescence in the Adult Hippocampal Phosphoproteome

Alcohol consumption during adolescence is known to cause different impairments in the hippocampus that could lead to persistent deficits in adulthood. A common pattern of alcohol use in adolescents consists of excessive and intermittent alcohol consumption over a very short period of time (binge drinking). Protein phosphorylation is a mechanism underlying memory processes and we have previously demonstrated changes in the rat hippocampal phosphoproteome after a single dose of ethanol; however, studies showing the phosphoprotein alterations in the hippocampus after repeated exposition to alcohol are limited. This study focuses on the identification of the phosphoproteins differentially regulated in the adolescent rat hippocampus after repeated ethanol administration by comparing different patterns of alcohol treatments according to dose and frequency of administration ((i) moderate dose-chronic use, (ii) low dose-intermittent use, and (iii) high dose-intermittent use). We have used a proteomic approach, including phosphoprotein enrichment by immobilized metal affinity chromatography, which revealed 21 proteins differentially affected depending on the pattern of alcohol treatment used. Many of these proteins are included in glycolysis and glucagon signaling pathways and are also involved in neurodegeneration, which could reinforce the role of metabolic alterations in the neural damage induced by repeated alcohol exposure during adolescence.

The intermittent administration of ethanol during the juvenile period produces changes in the expression of hippocampal genes and proteins and deterioration of spatial memory

BACKGROUND

Binge drinking is a pattern of alcohol intake characterized by excessive and intermittent alcohol consumption over a very short period of time that is more used during adolescence. We aim to compare the lasting effects of a chronic-moderate vs. this intermittent-excessive way of alcohol intake during adolescence in spatial memory and in the expression of glutamatergic receptors and GSK3β activity.

METHODS

Adolescent male Wistar rats were given ethanol/saline i.p. injections in four different groups: High-I (4 g/kg of a 25% (vol/vol) every 3 days), Low-I (1 g/kg of a 5% (vol/vol) every 3 days), M (0.3 g/kg of a 2.5% (vol/vol) daily) and Control (C, sterile isotonic saline daily). Rats received ethanol for up to five 3-day cycles. Spatial memory was measured by spontaneous alternation in the Y-Maze. Gene and protein expression of hippocampal proteins were also analysed.

RESULTS

Both high- and low-intermittent ethanol administration produced spatial memory impairment and changes in glutamatergic receptors gene expression were observed regardless of the pattern of exposure. High doses of intermittent alcohol administration produced an increase of phosphorylation of GSK3β Ser9. Moreover, moderate alcohol administration produced a down-regulation of the AMPAR 2/3 ratio despite lack of spatial memory deficits.

CONCLUSIONS

Excessive and intermittent ethanol exposure during adolescence impaired the spatial memory processes during adulthood regardless of the amount of alcohol administered. Moreover, chronic-moderate and intermittent pattern induced changes in the expression of glutamatergic receptors. In addition, high-intermittent ethanol exposure during adolescence inactivated GSK3β by increasing its phosphorylation in Ser9.

Ethanol-induced cognitive dysfunction is associated with alterations in the mammalian target of rapamycin signalling pathway in the hippocampus of male mice

The aim of the present study is to investigate the effect of acute excessive administration of ethanol on the expression of proteins related to the PI3K/Akt/mTOR signalling pathway in the mouse hippocampus and to reveal the possible molecular mechanism of learning and memory deficits induced by ethanol. A total of 120 8-week-old Kunming mice (half male and half female) were randomly assigned into low-dose, moderate-dose, and high-dose male and female groups with intragastric administration of 12.5, 25 and 50% ethanol, respectively, at the dosage of 0.1 ml/10 g·day for 14 days. The male and female control groups received an equal volume of distilled water. Then, the spatial learning and memory of the mice were evaluated by the Morris water maze task. The expression of p-mTOR, p-Akt, mTOR and Akt proteins was tested by western blotting and immunohistochemical staining methods in the hippocampal formation in each group, and haematoxylin-eosin stain was used to identify morphological changes in the hippocampal region. Our results indicated that 25 and 50% ethanol administration led to cognitive dysfunction and hippocampal pyramidal cell impairment in the female and male mice, with the male mice showing more severe impairment. In the 50% ethanol group, the male mice exhibited low expression levels of p-Akt and p-mTOR, but the female mice had no significant differences compared with the respective control group. Interestingly, the male expression levels of p-Akt and p-mTOR were significantly lower than those of females. Overall, these findings suggested that the cognitive deficits induced by ethanol are more serious in male mice than in female mice, and the PI3K/Akt/mTOR signalling pathway in the hippocampus might be involved in the impairment process.