Improving neurodevelopment in Zika-exposed children: A randomized controlled trial

Preventive effect of prenatal maternal oral probiotic supplementation on neonatal jaundice (POPS Study): A protocol for the randomised double-blind placebo-controlled clinical trial

INTRODUCTION

Neonatal jaundice is a common and life-threatening health problem in neonates due to overaccumulation of circulating unconjugated bilirubin. Gut flora has a potential influence on bilirubin metabolism. The infant gut microbiome is commonly copied from the maternal gut. During pregnancy, due to changes in dietary habits, hormones and body weight, maternal gut dysbiosis is common, which can be stabilised by probiotics supplementation. However, whether probiotic supplements can reach the baby through the mother and reduce the incidence of neonatal jaundice has not been studied yet. Therefore, we aim to evaluate the effect of prenatal maternal probiotic supplementation on the incidence of neonatal jaundice.

METHODS AND ANALYSIS

This is a randomised double-blind placebo-controlled clinical trial among 94 pregnant women (47 in each group) in a tertiary hospital in Hong Kong. Voluntary eligible participants will be recruited between 28 and 35 weeks of gestation. Computer-generated randomisation and allocation to either the intervention or control group will be carried out. Participants will take either one sachet of Vivomixx (450 billion colony-forming units per sachet) or a placebo per day until 1 week post partum. Neither the study participants nor researchers will know the randomisation and allocation. The intervention will be initiated at 36 weeks of gestation. Neonatal bilirubin level will be measured to determine the primary outcome (hyperbilirubinaemia) while the metagenomic microbiome profile of breast milk and maternal and infant stool samples as well as pregnancy outcomes will be secondary outcomes. Binary logistic and linear regressions will be carried out to assess the association of the microbiome data with different clinical outcomes.

ETHICS AND DISSEMINATION

Ethics approval is obtained from the Joint CUHK-NTEC Clinical Research Ethics Committee, Hong Kong (CREC Ref: 2023.100-T). Findings will be published in peer-reviewed journals and presented at international conferences.

TRIAL REGISTRATION NUMBER

NCT06087874.

Zika virus co-opts microRNA networks to persist in placental niches detected by spatial transcriptomics

BACKGROUND

Zika virus congenital infection evades double-stranded RNA detection and may persist in the placenta for the duration of pregnancy without accompanying overt histopathologic inflammation. Understanding how viruses can persist and replicate in the placenta without causing overt cellular or tissue damage is fundamental to deciphering mechanisms of maternal-fetal vertical transmission.

OBJECTIVE

Placenta-specific microRNAs are believed to be a tenet of viral resistance at the maternal-fetal interface. We aimed to test the hypothesis that the Zika virus functionally disrupts placental microRNAs, enabling viral persistence and fetal pathogenesis.

STUDY DESIGN

To test this hypothesis, we used orthogonal approaches in human and murine experimental models. In primary human trophoblast cultures (n=5 donor placentae), we performed Argonaute high-throughput sequencing ultraviolet-crosslinking and immunoprecipitation to identify any significant alterations in the functional loading of microRNAs and their targets onto the RNA-induced silencing complex. Trophoblasts from same-donors were split and infected with a contemporary first-passage Zika virus strain HN16 (multiplicity of infection=1 plaque forming unit per cell) or mock infected. To functionally cross-validate microRNA-messenger RNA interactions, we compared our Argonaute high-throughput sequencing ultraviolet-crosslinking and immunoprecipitation results with an independent analysis of published bulk RNA-sequencing data from human placental disk specimens (n=3 subjects; Zika virus positive in first, second, or third trimester, CD45- cells sorted by flow cytometry) and compared it with uninfected controls (n=2 subjects). To investigate the importance of these microRNA and RNA interference networks in Zika virus pathogenesis, we used a gnotobiotic mouse model uniquely susceptible to the Zika virus. We evaluated if small-molecule enhancement of microRNA and RNA interference pathways with enoxacin influenced Zika virus pathogenesis (n=20 dams total yielding 187 fetal specimens). Lastly, placentae (n=14 total) from this mouse model were analyzed with Visium spatial transcriptomics (9743 spatial transcriptomes) to identify potential Zika virus-associated alterations in immune microenvironments.

RESULTS

We found that Zika virus infection of primary human trophoblast cells led to an unexpected disruption of placental microRNA regulation networks. When compared with uninfected controls, Zika virus-infected placentae had significantly altered SLC12A8, SDK1, and VLDLR RNA-induced silencing complex loading and transcript levels (-22; adjusted P value <.05; Wald-test with false discovery rate correction q<0.05). In silico microRNA target analyses revealed that 26 of 119 transcripts (22%) in the transforming growth factor-β signaling pathway were targeted by microRNAs that were found to be dysregulated following Zika virus infection in trophoblasts. In gnotobiotic mice, relative to mock controls, Zika virus-associated fetal pathogenesis included fetal growth restriction (P=.036) and viral persistence in placental tissue (P=.011). Moreover, spatial transcriptomics of murine placentae revealed that Zika virus-specific placental niches were defined by significant up-regulation of complement cascade components and coordinated changes in transforming growth factor-β gene expression. Finally, treatment of Zika virus-infected mice with enoxacin abolished placental Zika virus persistence, rescued the associated fetal growth restriction, and the Zika virus-associated transcriptional changes in placental immune microenvironments were no longer observed.

CONCLUSION

These results collectively suggest that (1) Zika virus infection and persistence is associated with functionally perturbed microRNA and RNA interference pathways specifically related to immune regulation in placental microenvironments and (2) enhancement of placental microRNA and RNA interference pathways in mice rescued Zika virus-associated pathogenesis, specifically persistence of viral transcripts in placental microenvironments and fetal growth restriction.

Neurodevelopmental assessment of normocephalic children born to Zika virus exposed and unexposed pregnant people

BACKGROUND

Studies examining the association between in utero Zika virus (ZIKV) exposure and child neurodevelopmental outcomes have produced varied results.

METHODS

We aimed to assess neurodevelopmental outcomes among normocephalic children born from pregnant people enrolled in the Zika in Pregnancy in Honduras (ZIPH) cohort study, July-December 2016. Enrollment occurred during the first prenatal visit. Exposure was defined as prenatal ZIKV IgM and/or ZIKV RNA result at enrollment. Normocephalic children, >6 months old, were selected for longitudinal follow-up using the Bayley Scales of Infant and Toddler Development (BSID-III) and the Ages & Stages Questionnaires: Social-Emotional (ASQ:SE-2).

RESULTS

One hundred fifty-two children were assessed; after exclusion, 60 were exposed and 72 were unexposed to ZIKV during pregnancy. Twenty children in the exposed group and 21 children in the unexposed group had a composite score <85 in any of the BSID-III domains. Although exposed children had lower cognitive and language scores, differences were not statistically significant. For ASQ:SE-2 assessment, there were not statistically significant differences between groups.

CONCLUSIONS

This study found no statistically significant differences in the neurodevelopment of normocephalic children between in utero ZIKV exposed and unexposed. Nevertheless, long-term monitoring of children with in utero ZIKV exposure is warranted.

IMPACT

This study found no statistically significant differences in the neurodevelopment in normocephalic children with in utero Zika virus exposure compared to unexposed children, although the exposed group showed lower cognitive and language scores that persisted after adjustment by maternal age and education and after excluding children born preterm and low birth weight from the analysis. Children with prenatal Zika virus exposure, including those normocephalic and have no evidence of abnormalities at birth, should be monitored for neurodevelopmental delays. Follow-up is important to be able to detect developmental abnormalities that might not be detected earlier in life.

Dengue, chikungunya and zika arbovirus infections in Caribbean children

PURPOSE OF REVIEW

Dengue, chikungunya and zika have caused significant epidemics in the Caribbean in recent years. This review highlights their impact in Caribbean children.

RECENT FINDINGS

Dengue has been increasingly intense and severe, seroprevalence is 80-100% in the Caribbean, children have increased attributable morbidity and mortality. Severe dengue, especially dengue with haemorrhage was significantly associated with haemoglobin SC disease and multiple organ-systems involved. These included the gastrointestinal and haematologic systems with extremely high lactate dehydrogenases and creatinine phosphokinases and severely abnormal bleeding indices. Despite appropriate interventions, mortality was highest within the first 48 h of admission. Chikungunya, a togavirus, affected 80% of some Caribbean populations. Paediatric presentations included high fever, skin, joint and neurological manifestations. Children less than 5 years of age had the highest morbidity and mortality. This maiden chikungunya epidemic was explosive and overwhelmed public health systems. Zika, another flavivirus, has a seroprevalence of 15% in pregnancy, so the Caribbean remains susceptible. Paediatric complications include pregnancy losses, stillbirths, Congenital Zika syndrome, Guillain-Barre syndrome, acute disseminated encephalomyelitis and transverse myelitis. Neurodevelopment stimulation programs for zika-exposed infants have been effective in improving language and positive behaviour scores.

SUMMARY

Caribbean children remain at risk for dengue, chikungunya and zika, with high attributable morbidity and mortality.