Burden of infection in Australian infants

Neonatal Chlamydia muridarum respiratory infection causes neuroinflammation within the brainstem during the early postnatal period

Respiratory infections are one of the most common causes of illness and morbidity in neonates worldwide. In the acute phase infections are known to cause wide-spread peripheral inflammation. However, the inflammatory consequences to the critical neural control centres for respiration have not been explored. Utilising a well characterised model of neonatal respiratory infection, we investigated acute responses within the medulla oblongata which contains key respiratory regions. Neonatal mice were intranasally inoculated within 24 h of birth, with either Chlamydia muridarum or sham-infected, and tissue collected on postnatal day 15, the peak of peripheral inflammation. A key finding of this study is that, while the periphery appeared to show no sex-specific effects of a neonatal respiratory infection, sex had a significant impact on the inflammatory response of the medulla oblongata. There was a distinct sex-specific response in the medulla coincident with peak of peripheral inflammation, with females demonstrating an upregulation of anti-inflammatory cytokines and males showing very few changes. Microglia also demonstrated sex-specificity with the morphology of females and males differing based upon the nuclei. Astrocytes showed limited changes during the acute response to neonatal infection. These data highlight the strong sex-specific impact of a respiratory infection can have on the medulla in the acute inflammatory phase.

Vedolizumab and Ustekinumab Levels in Pregnant Women With Inflammatory Bowel Disease and Infants Exposed In Utero

BACKGROUND & AIMS

Vedolizumab and ustekinumab pharmacokinetics in pregnancy and the infant after in utero exposure remain incompletely defined. We aim to define the antenatal stability of ustekinumab and vedolizumab levels and the time at which infant drug levels become undetectable.

METHODS

This multicenter prospective observational cohort study recruited pregnant or preconception women with inflammatory bowel disease receiving vedolizumab or ustekinumab. Trough drug levels, clinical data, and biochemical data were documented preconception, during each trimester of pregnancy, and postpartum. Maternal and cord blood drug levels were measured at delivery and in infants until undetectable. Infant outcomes were assessed until 2 years of age.

RESULTS

A total of 102 participants (vedolizumab, n = 58) were included. The majority of mothers were, and remained, in clinical and biochemical remission. Maternal vedolizumab levels decreased over the course of pregnancy in association with increasing weight, rather than increasing gestation. Maternal ustekinumab levels remained stable. The median time to drug becoming undetectable in the infant was shorter for vedolizumab (11 wk; range, 5-19 wk; n = 32) than ustekinumab (14 wk; range, 9-36 wk; n = 17) and correlated positively with infant delivery level. Thirty-two of 41 (88%) and 17 of 30 (67%) vedolizumab- and ustekinumab-exposed infants had undetectable drug levels by 15 weeks of age, respectively. Pregnancy and infant outcomes were favorable. Twenty infants with undetectable drug levels received the rotavirus vaccine, with no adverse reactions reported.

CONCLUSIONS

Maternal vedolizumab levels decreased, whereas ustekinumab levels remained stable over the course of pregnancy. Most vedolizumab- and approximately half of ustekinumab-exposed infants had undetectable drug levels by 15 weeks of age. No concerning maternal or infant safety signals were identified.

Key risk factors of asthma-like symptoms are mediated through infection burden in early childhood

BACKGROUND

Risk factors of asthma-like symptoms in childhood may act through an increased infection burden because infections often trigger these symptoms.

OBJECTIVE

We sought to investigate whether the effect of established risk factors of asthma-like episodes in early childhood is mediated through burden and subtypes of common infections.

METHODS

The study included 662 children from the Copenhagen Prospective Studies on Asthma in Childhood 2010 mother-child cohort, in which infections were registered prospectively in daily diaries from age 0 to 3 years. The association between established risk factors of asthma-like episodes and infection burden was analyzed by quasi-Poisson regressions, and mediation analyses were performed for significant risk factors.

RESULTS

In the first 3 years of life, the children experienced a median of 16 (interquartile range, 12-23) infectious episodes. We found that the infection burden significantly (PACME < .05) mediated the association of maternal asthma (36.6% mediated), antibiotics during pregnancy (47.3%), siblings at birth (57.7%), an asthma exacerbation polygenic risk score (30.6%), and a bacterial airway immune score (80.2%) with number of asthma-like episodes, whereas the higher number of episodes from male sex, low birth weight, low gestational age, and maternal antibiotic use after birth was not mediated through an increased infection burden. Subtypes of infections driving the mediation were primarily colds, pneumonia, gastroenteritis, and fever, but not acute otitis media or acute tonsillitis.

CONCLUSIONS

Several risk factors of asthma-like symptoms in early childhood act through an increased infection burden in the first 3 years of life. Prevention of infectious episodes may therefore be beneficial to reduce the burden of asthma-like symptoms in early childhood.

Contrasting Health Outcomes following a Severe Smoke Episode and Ambient Air Pollution in Early Life: Findings from an Australian Data Linkage Cohort Study of Hospital Utilization

BACKGROUND

Episodic spikes in air pollution due to landscape fires are increasing, and their potential for longer term health impacts is uncertain.

OBJECTIVE

Our objective is to evaluate associations between exposure in utero and in infancy to severe pollution from a mine fire, background ambient air pollution, and subsequent hospital care.

METHODS

We linked health records of births, emergency department (ED) visits, and hospitalizations of children born in the Latrobe Valley, Australia, 2012-2015, which included a severe pollution episode from a mine fire (9 February 2014 to 25 March 2014). We assigned modeled exposure estimates for fire-related and ambient particulate matter with an aerodynamic diameter of 2.5 μ m (PM 2.5 ) to residential address. We used logistic regression to estimate associations with hospital visits for any cause and groupings of infectious, allergic, and respiratory conditions. Outcomes were assessed for the first year of life in the in utero cohort and the year following the fire in the infant cohort. We estimated exposure-response for both fire-related and ambient PM 2.5 and also employed inverse probability weighting using the propensity score to compare exposed and not/minimally exposed children.

RESULTS

Prenatal exposure to fire-related PM 2.5 was associated with ED presentations for allergies/skin rash [odds ratio ( OR ) = 1.34 , 95% confidence interval (CI): 1.01, 1.76 per 240   μ g / m 3 increase]. Exposure in utero to ambient PM 2.5 was associated with overall presentations (OR = 1.18 , 95% CI: 1.05, 1.33 per 1.4   μ g / m 3 ) and visits for infections (ED: OR = 1.13 , 95% CI: 0.98, 1.29; hospitalizations: OR = 1.23 , 95% CI: 1.00, 1.52). Exposure in infancy to fire-related PM 2.5 compared to no/minimal exposure, was associated with ED presentations for respiratory (OR = 1.37 , 95% CI: 1.05, 1.80) and infectious conditions (any: OR = 1.21 , 95% CI: 0.98, 1.49; respiratory-related: OR = 1.39 , 95% CI: 1.05, 1.83). Early life exposure to ambient PM 2.5 was associated with overall ED visits (OR = 1.17 , 95% CI: 1.05, 1.30 per 1.4   μ g / m 3 increase).

DISCUSSION

Higher episodic and lower ambient concentrations of PM 2.5 in early life were associated with visits for allergic, respiratory, and infectious conditions. Our findings also indicated differences in associations at the two developmental stages. https://doi.org/10.1289/EHP12238.

Early life infection and proinflammatory, atherogenic metabolomic and lipidomic profiles in infancy: a population-based cohort study

Background:

The risk of adult onset cardiovascular and metabolic (cardiometabolic) disease accrues from early life. Infection is ubiquitous in infancy and induces inflammation, a key cardiometabolic risk factor, but the relationship between infection, inflammation, and metabolic profiles in early childhood remains unexplored. We investigated relationships between infection and plasma metabolomic and lipidomic profiles at age 6 and 12 months, and mediation of these associations by inflammation.

Methods:

Matched infection, metabolomics, and lipidomics data were generated from 555 infants in a pre-birth longitudinal cohort. Infection data from birth to 12 months were parent-reported (total infections at age 1, 3, 6, 9, and 12 months), inflammation markers (high-sensitivity C-reactive protein [hsCRP]; glycoprotein acetyls [GlycA]) were quantified at 12 months. Metabolic profiles were 12-month plasma nuclear magnetic resonance metabolomics (228 metabolites) and liquid chromatography/mass spectrometry lipidomics (776 lipids). Associations were evaluated with multivariable linear regression models. In secondary analyses, corresponding inflammation and metabolic data from birth (serum) and 6-month (plasma) time points were used.

Results:

At 12 months, more frequent infant infections were associated with adverse metabolomic (elevated inflammation markers, triglycerides and phenylalanine, and lower high-density lipoprotein [HDL] cholesterol and apolipoprotein A1) and lipidomic profiles (elevated phosphatidylethanolamines and lower trihexosylceramides, dehydrocholesteryl esters, and plasmalogens). Similar, more marked, profiles were observed with higher GlycA, but not hsCRP. GlycA mediated a substantial proportion of the relationship between infection and metabolome/lipidome, with hsCRP generally mediating a lower proportion. Analogous relationships were observed between infection and 6-month inflammation, HDL cholesterol, and apolipoprotein A1.

Conclusions:

Infants with a greater infection burden in the first year of life had proinflammatory and proatherogenic plasma metabolomic/lipidomic profiles at 12 months of age that in adults are indicative of heightened risk of cardiovascular disease, obesity, and type 2 diabetes. These findings suggest potentially modifiable pathways linking early life infection and inflammation with subsequent cardiometabolic risk.

Funding:

The establishment work and infrastructure for the BIS was provided by the Murdoch Children’s Research Institute (MCRI), Deakin University, and Barwon Health. Subsequent funding was secured from National Health and Medical Research Council of Australia (NHMRC), The Shepherd Foundation, The Jack Brockhoff Foundation, the Scobie & Claire McKinnon Trust, the Shane O’Brien Memorial Asthma Foundation, the Our Women’s Our Children’s Fund Raising Committee Barwon Health, the Rotary Club of Geelong, the Minderoo Foundation, the Ilhan Food Allergy Foundation, GMHBA, Vanguard Investments Australia Ltd, and the Percy Baxter Charitable Trust, Perpetual Trustees. In-kind support was provided by the Cotton On Foundation and CreativeForce. The study sponsors were not involved in the collection, analysis, and interpretation of data; writing of the report; or the decision to submit the report for publication. Research at MCRI is supported by the Victorian Government’s Operational Infrastructure Support Program. This work was also supported by NHMRC Senior Research Fellowships to ALP (1008396); DB (1064629); and RS (1045161) , NHMRC Investigator Grants to ALP (1110200) and DB (1175744), NHMRC-A*STAR project grant (1149047). TM is supported by an MCRI ECR Fellowship. SB is supported by the Dutch Research Council (452173113).

Exposure to antibiotics during pregnancy alters offspring outcomes

INTRODUCTION

The composition of microorganisms is closely related to human health. Antibiotic use during pregnancy may have adverse effects on the neonatal gut microbiome and subsequently affect infant health development, leading to childhood atopy and allergic diseases, intestinal, metabolic and brain disorders, and infection.

AREAS COVERED

This review includes the effect of maternal antibiotic use during pregnancy on potential diseases in animals and human offspring.

EXPERT OPINION

Exposure to antibiotics during pregnancy alters offspring outcomes. Alterations in the microbiome may potentially lower the risk of a range of problems and may also be a novel therapeutic target in children later in life.