Deep phenotyping of the unselected COPSAC2010 birth cohort study

BACKGROUND

We hypothesize that perinatal exposures, in particular the human microbiome and maternal nutrition during pregnancy, interact with the genetic predisposition to cause an abnormal immune modulation in early life towards a trajectory to chronic inflammatory diseases such as asthma and others.

OBJECTIVE

The aim of this study is to explore these interactions by conducting a longitudinal study in an unselected cohort of pregnant women and their offspring with emphasis on deep clinical phenotyping, exposure assessment, and biobanking. Exposure assessments focus on the human microbiome. Nutritional intervention during pregnancy in randomized controlled trials are included in the study to prevent disease and to be able to establish causal relationships.

METHODS

Pregnant women from eastern Denmark were invited during 2008-2010 to a novel unselected 'COPSAC2010 ' cohort. The women visited the clinic during pregnancy weeks 24 and 36. Their children were followed at the clinic with deep phenotyping and collection of biological samples at nine regular visits until the age of 3 and at acute symptoms. Randomized controlled trials of high-dose vitamin D and fish oil supplements were conducted during pregnancy, and a trial of azithromycin for acute lung symptoms was conducted in the children with recurrent wheeze.

RESULTS

Seven hundred and thirty-eight mothers were recruited from week 24 of gestation, and 700 of their children were included in the birth cohort. The cohort has an over-representation of atopic parents. The participant satisfaction was high and the adherence equally high with 685 children (98%) attending the 1 year clinic visit and 667 children (95%) attending the 2 year clinic visit.

CONCLUSIONS

The COPSAC2010 birth cohort study provides longitudinal clinical follow-up with highly specific end-points, exposure assessments, and biobanking. The cohort has a high adherence rate promising strong data to elucidate the interaction between genomics and the exposome in perinatal life leading to lifestyle-related chronic inflammatory disorders such as asthma.

Domestic dog exposure at birth reduces the incidence of atopic dermatitis

BACKGROUND

While the etiopathogenesis of atopic dermatitis is complex and poorly understood, neonatal exposures are important for disease occurrence. However, the effect of dog exposure on the risk of atopic dermatitis is unresolved.

OBJECTIVE

We investigated whether domestic dog exposure affected the risk of atopic dermatitis in children during the first 3 years of life.

METHODS

Copenhagen Prospective Studies on Asthma in Childhood (COPSAC) are ongoing prospective clinical birth cohort studies. Data from 411 children born to mothers with asthma (COPSAC₂₀₀₀ ) and 700 unselected children (COPSAC₂₀₁₀ ) were analyzed following the same protocols at the same research site. Atopic dermatitis was diagnosed prospectively according to the Hanifin-Rajka criteria. Parental history of asthma, eczema, or rhinitis was defined by self-reported physician diagnosis. In the COPSAC₂₀₀₀ , maternal specific serum IgE against eight inhalant allergens was sampled after the children's birth and at pregnancy week 24 in the COPSAC₂₀₁₀ cohort. Associations between dog exposure and atopic dermatitis were analyzed by Cox proportional hazard regression models and adjusted for lifestyle confounders.

RESULTS

In the COPSAC₂₀₀₀ and COPSAC₂₀₁₀ cohorts, the risk of atopic dermatitis was significantly lower in children with domestic dog exposure (_adjusted HR = 0.46 [0.25-0.87], P = 0.02; and _adjusted HR = 0.58 [0.36-0.93], P = 0.03, respectively). The risk of atopic dermatitis decreased in a dose-dependent manner with increasing number of dogs (_adjusted HR = 0.58 [0.38-0.89], P = 0.01) in the COPSAC₂₀₁₀ . The protective effect was restricted to children born to mothers with atopic disease in the unselected COPSAC₂₀₁₀ cohort (_adjusted HR = 0.39 [0.19-0.82], P = 0.01), as no effect was observed in children born to mothers without atopic disease (_adjusted HR = 0.92 [0.49-1.73], P = 0.79). Paternal atopic status did not affect the risk of atopic dermatitis. We found no significant interaction between the CD14 T/T genotype and domestic dog exposure in either cohort (COPSAC₂₀₀₀ , P = 0.36; and COPSAC₂₀₁₀ cohort, P = 0.42).

CONCLUSION

Neonatal domestic dog exposure was associated with a strongly reduced risk of atopic dermatitis in two independent birth cohorts and in a dose-dependent manner. While the mechanisms involved are unclear, our findings raise the question of whether in utero exposures may affect the risk of atopic dermatitis and emphasize the importance of the early environment for disease trajectory.

VEGFA variants are associated with pre-school lung function, but not neonatal lung function

BACKGROUND

Vascular endothelial growth factor (VEGF) is implicated in airway remodelling and asthma development. We studied VEGFA gene variants and plasma levels and the development of lung function, bronchial hyperresponsiveness and asthma in childhood.

METHODS

We analysed 13 SNPs in the VEGFA gene in 411 children from the COPSAC2000 high-risk birth cohort. Asthma was diagnosed prospectively, and lung function measurements were obtained at birth and 6 years of age. Plasma VEGF levels were measured at 18 months of age. We used a Bonferroni adjusted significance level. Findings were replicated in the Prevention and Incidence of Asthma and Mite Allergy (PIAMA) birth cohort at age 8.

RESULTS

At age six, three SNPs from the same linkage block were associated with FEV1 (rs699947, P = 1.31E-05), independent of asthma, and there were suggestive associations between FEV1/FVC ratio and rs833052 and maximal mid-expiratory flow and rs6900017. Replication in the PIAMA cohort showed borderline association between FEV1 and rs699947 and significant meta-analysis result. SNPs upstream and nearby rs699947 were nominally associated with VEGF plasma levels. VEGF levels were not associated with asthmatic symptoms or lung function measures.

CONCLUSIONS AND CLINICAL RELEVANCE

VEGF gene variants are associated with lung function at school age, but not at birth, suggesting a role of VEGF in post-natal lung function development.

Systemic exposure to inhaled beclometasone/formoterol DPI is age and body size dependent

AIM

Prescription of inhaled corticosteroids to children with asthma is recommended at half the nominal dose of adults in order to reduce the risk of systemic side effects. However, there is a lack of pharmacokinetic trials supporting such dose reduction regimens. Therefore, we aimed to compare the systemic exposure to the active ingredients of a fixed dose combination of beclometasone-dipropionate (BDP) and formoterol after dry powder inhaler (DPI) administration in children, adolescents and adults.

METHODS

The pharmacokinetic profiles of formoterol and beclometasone-17-monopropionate (B17MP; active metabolite of BDP) were evaluated over 8 h from two independent studies comprising children (6-11yrs, n = 27), adolescents (12-17 yrs, n = 28) and adults (≥18 yrs, n = 30) receiving a single, fixed dose of BDP/formoterol (children: 200 μg/24 μg, adolescents and adults: 400 μg/24 μg) via DPI.

RESULTS

The systemic exposure (AUC) for children versus adults was almost doubled for formoterol and similar for B17MP despite the halved BDP dose administered in children. In adolescents the AUC for formoterol and B17MP were approximately one third higher than in adults for both compounds. Upon normalization for the BDP/formoterol dose in the three populations the AUC and peak concentration (C(max)) correlated inversely with age and body surface area of the patients (r ≤ -0.53; p < 0.0001).

CONCLUSION

The systemic exposure to the active ingredients of BDP/formoterol administered as DPI correlates inversely with age and body size suggesting that dry powder dosage regimens should be adjusted for age and body size to avoid high systemic drug levels in children.

A single-source nosocomial outbreak of Aspergillus flavus uncovered by genotyping

During construction work (2017-2019), an increase in Aspergillus flavus infections was noted among pediatric patients, the majority of whom were receiving amphotericin B prophylaxis. Microsatellite genotyping was used to characterize the outbreak. A total of 153 A. flavus isolates of clinical and environmental origin were included. Clinical isolates included 140 from 119 patients. Eight patients were outbreak-related patients, whereas 111 were outbreak-unrelated patients from Danish hospitals (1994-2023). We further included four control strains. Nine A. flavus isolates were from subsequent air sampling in the outbreak ward (2022-2023). Typing followed Rudramurthy et al.(S. M. Rudramurthy, H. A. de Valk, A. Chakrabarti, J. Meis, and C. H. W. Klaassen, PLoS One 6:e16086, 2011, https://doi.org/10.1371/journal.pone.0016086). Minimum spanning tree (MST) and discriminant analysis of principal components (DAPC) were used for cluster analysis. DAPC analysis placed all 153 isolates in five clusters. Microsatellite marker pattern was clearly distinct for one cluster compared to the others. The same cluster was observed in an MST. This cluster included all outbreak isolates, air-sample isolates, and additional patient isolates from the outbreak hospital, previously undisclosed as outbreak related. The highest air prevalence of A. flavus was found in two technical risers of the outbreak ward, which were then sealed. Follow-up air samples were negative for A. flavus. Microsatellite typing defined the outbreak as nosocomial and facilitated the identification of an in-hospital source. Six months of follow-up air sampling was without A. flavus. Outbreak-related/non-related isolates were easily distinguished with DAPC and MST, as the outbreak clone's distinct marker pattern was delineated in both statistical analyses. Thus, it could be a variant of A. flavus, with a niche ability to thrive in the outbreak-hospital environment.

IMPORTANCE

Aspergillus flavus can cause severe infections and hospital outbreaks in immunocompromised individuals. Although lack of isogeneity does not preclude an outbreak, our study underlines the value of microsatellite genotyping in the setting of potential A. flavus outbreaks. Microsatellite genotyping documented an isogenic hospital outbreak with an internal source. This provided the "smoking gun" that prompted the rapid allocation of resources for thorough environmental sampling, the results of which guided immediate and relevant cleaning and source control measures. Consequently, we advise that vulnerable patients should be protected from exposure and that genotyping be included early in potential A. flavus outbreak investigations. Inspection and sampling are recommended at any site where airborne spores might disperse from. This includes rarely accessed areas where air communication to the hospital ward cannot be disregarded.

Indocyanine green clearance's association with liver function in paediatric liver disease

AIM

Indocyanine green (ICG) clearance, a sensitive biomarker for liver function, has not been validated in children. We assessed the association between ICG clearance and liver function in children with liver disease.

METHODS

ICG plasma disappearance rate (ICG-PDR, %/min) was measured in children with liver disease. Mixed linear regression was used to assess the relationship between ICG-PDR and liver function tests (international normalised ratio, INR; prothrombin-proconvertin clotting time, PP).

RESULTS

We included 124 patients with 183 visits. Of the visits, 60.1% were female, 85% had chronic liver disease and 42.5% were liver transplanted. The most common diseases in those without transplantation were autoimmune disease (18.6%) and biliary atresia (10.9%). Median ICG-PDR was 23.9%/min (interquartile range 15; 30.3). Mixed linear regression showed ICG-PDR was associated with INR (β = -0.006, 95% CI [-0.010, -0.003]) and PP (β = 0.005, 95% CI [0.003, 0.008]). However, only five visits were with patients who had acute liver failure (INR ≥2.0).

CONCLUSION

ICG clearance is associated with standard measures of liver function in children. ICG may aid decision-making in paediatric liver disease together with other biochemical measures, imaging and clinical presentation. However, further studies are needed to assess the usefulness of ICG in paediatric patients with INR >1.4.