Correction to: Brief Report: Maternal Opioid Prescription from Preconception Through Pregnancy and the Odds of Autism Spectrum Disorder and Autism Features in Children

Prenatal exposure to opioids and neurodevelopment in infancy and childhood: A systematic review

Aim

This systematic review aims to estimate the relationship between prenatal exposure to opioids and neurodevelopmental outcomes and examines potential sources of heterogeneity between the studies.

Methods

We searched four databases through May 21st, 2022: PubMed, Embase, PsycInfo and the Web of Science according to a specified search strings. Study inclusion criteria include: (1) cohort and case-control peer-reviewed studies published in English; (2) studies comparing neurodevelopmental outcomes among children with prenatal opioid-exposure (prescribed or used non-medically) vs. an unexposed group. Studies investigating fetal alcohol syndrome or a different primary prenatal exposure other than opioids were excluded. Two main performed data extraction using "Covidence" systematic review platform. This systematic review was conducted in accordance with PRISMA guidelines. The Newcastle-Ottawa-Scale was used for quality assessment of the studies. Studies were synthesized based on the type of neurodevelopmental outcome and the instrument used to assess neurodevelopment.

Results

Data were extracted from 79 studies. We found significant heterogeneity between studies due to their use of different instruments to explore cognitive skills, motor, and behavioral outcomes among children of different ages. The other sources of heterogeneity included: procedures to assess prenatal exposure to opioids; period of pregnancy in which exposure was assessed; type of opioids assessed (non-medical, medication used for opioid use dis-order, prescribed by health professional), types of co-exposure; source of selection of prenatally exposed study participants and comparison groups; and methods to address lack of comparability between exposed and unexposed groups. Cognitive and motor skills as well as behavior were generally negatively affected by prenatal opioid exposure, but the significant heterogeneity precluded a meta-analysis.

Conclusion

We explored sources of heterogeneity in the studies assessing the association between prenatal exposure to opioids and neurodevelopmental outcomes. Sources of heterogeneity included different approaches to participant recruitment as well as exposure and outcome ascertainment methods. Nonetheless, overall negative trends were observed between prenatal opioid exposure and neuro-developmental outcomes.

Fentanyl induces autism-like behaviours in mice by hypermethylation of the glutamate receptor gene Grin2b

BACKGROUND

Environmental factors contribute to autism spectrum disorder. Fentanyl, one of the most widely used opioid analgesics in anaesthesia, can induce neurotoxicity, but its role in autism remains unknown. We determined whether fentanyl induced autism-like behaviours in young mice and the underlying mechanisms.

METHODS

Young male and female mice received fentanyl at postnatal days 6, 8, and 10, and performed behavioural tests, including three-chamber social preference, elevated plus maze, grooming behaviour, and open-field test, from postnatal days 30-32. Expression of Grin2b, the gene encoding the GluN2B subunit of the N-methyl-d-aspartate receptor, was assessed in the anterior cingulate cortex of male mice using fluorescence in situ hybridisation histochemistry. We used bisulfite target sequencing to determine Grin2b hypermethylation sites after fentanyl treatment. In the specific activation and rescue experiments, we injected the mu opioid receptor agonist [D-Ala,² N-MePhe,⁴ Gly-ol]-enkephalin (DAMGO) or Grin2b overexpression lentivirus into the anterior cingulate cortex of male mice.

RESULTS

Fentanyl induced autism-like behaviours in both young male and female mice, and downregulated Grin2b expression (0.49-fold [0.08] vs 1.00-fold [0.09]; P<0.01) and GluN2B protein amounts (0.38-fold [0.07] vs 1.00-fold [0.12]; P<0.01) in the anterior cingulate cortex through hypermethylation of Grin2b. The mu-opioid receptor antagonist naloxone and overexpression of Grin2b in anterior cingulate cortex attenuated the fentanyl-induced effects, whereas DAMGO injection into the anterior cingulate cortex induced autism-like behaviours.

CONCLUSIONS

These data suggest that fentanyl induces autism-like behaviours in young mice via an epigenetic mechanism. Further research is required to determine possible clinical relevance to autism risk.