Can HRCT be used as a marker of airway remodelling in children with difficult asthma?

BACKGROUND: Whole airway wall thickening on high resolution computed tomography (HRCT) is reported to parallel thickening of the bronchial epithelial reticular basement membrane (RBM) in adult asthmatics. A similar relationship in children with difficult asthma (DA), in whom RBM thickening is a known feature, may allow the use of HRCT as a non-invasive marker of airway remodelling. We evaluated this relationship in children with DA. METHODS: 27 children (median age 10.5 [range 4.1-16.7] years) with DA, underwent endobronchial biopsy from the right lower lobe and HRCT less than 4 months apart. HRCTs were assessed for bronchial wall thickening (BWT) of the right lower lobe using semi-quantitative and quantitative scoring techniques. The semi-quantitative score (grade 0-4) was an overall assessment of BWT of all clearly identifiable airways in HRCT scans. The quantitative score (BWT %; defined as [airway outer diameter - airway lumen diameter]/airway outer diameter x100) was the average score of all airways visible and calculated using electronic endpoint callipers. RBM thickness in endobronchial biopsies was measured using image analysis. 23/27 subjects performed spirometry and the relationships between RBM thickness and BWT with airflow obstruction evaluated. RESULTS: Median RBM thickness in endobronchial biopsies was 6.7(range 4.6-10.0) microm. Median qualitative score for BWT of the right lower lobe was 1(range 0-1.5) and quantitative score was 54.3 (range 48.2-65.6)%. There was no relationship between RBM thickness and BWT in the right lower lobe using either scoring technique. No relationship was found between FEV1 and BWT or RBM thickness. CONCLUSION: Although a relationship between RBM thickness and BWT on HRCT has been found in adults with asthma, this relationship does not appear to hold true in children with D

Previous influenza infection exacerbates allergen specific response and impairs airway barrier integrity in pre‐sensitized mice

In this study we assessed the effects of antigen exposure in mice pre-sensitized with allergen following viral infection on changes in lung function, cellular responses and tight junction expression. Female BALB/c mice were sensitized to ovalbumin and infected with influenza A before receiving a second ovalbumin sensitization and challenge with saline, ovalbumin (OVA) or house dust mite (HDM). Fifteen days post-infection, bronchoalveolar inflammation, serum antibodies, responsiveness to methacholine and barrier integrity were assessed. There was no effect of infection alone on bronchoalveolar lavage cellular inflammation 15 days post-infection; however, OVA or HDM challenge resulted in increased bronchoalveolar inflammation dominated by eosinophils/neutrophils or neutrophils, respectively. Previously infected mice had higher serum OVA-specific IgE compared with uninfected mice. Mice previously infected, sensitized and challenged with OVA were most responsive to methacholine with respect to airway resistance, while HDM challenge caused significant increases in both tissue damping and tissue elastance regardless of previous infection status. Previous influenza infection was associated with decreased claudin-1 expression in all groups and decreased occludin expression in OVA or HDM-challenged mice. This study demonstrates the importance of the respiratory epithelium in pre-sensitized individuals, where influenza-infection-induced barrier disruption resulted in increased systemic OVA sensitization and downstream effects on lung function

Air Trapping on Chest CT Is Associated with Worse Ventilation Distribution in Infants with Cystic Fibrosis Diagnosed following Newborn Screening

BACKGROUND: In school-aged children with cystic fibrosis (CF) structural lung damage assessed using chest CT is associated with abnormal ventilation distribution. The primary objective of this analysis was to determine the relationships between ventilation distribution outcomes and the presence and extent of structural damage as assessed by chest CT in infants and young children with CF. METHODS: Data of infants and young children with CF diagnosed following newborn screening consecutively reviewed between August 2005 and December 2009 were analysed. Ventilation distribution (lung clearance index and the first and second moment ratios [LCI, M(1)/M(0) and M(2)/M(0), respectively]), chest CT and airway pathology from bronchoalveolar lavage were determined at diagnosis and then annually. The chest CT scans were evaluated for the presence or absence of bronchiectasis and air trapping. RESULTS: Matched lung function, chest CT and pathology outcomes were available in 49 infants (31 male) with bronchiectasis and air trapping present in 13 (27%) and 24 (49%) infants, respectively. The presence of bronchiectasis or air trapping was associated with increased M(2)/M(0) but not LCI or M(1)/M(0). There was a weak, but statistically significant association between the extent of air trapping and all ventilation distribution outcomes. CONCLUSION: These findings suggest that in early CF lung disease there are weak associations between ventilation distribution and lung damage from chest CT. These finding are in contrast to those reported in older children. These findings suggest that assessments of LCI could not be used to replace a chest CT scan for the assessment of structural lung disease in the first two years of life. Further research in which both MBW and chest CT outcomes are obtained is required to assess the role of ventilation distribution in tracking the progression of lung damage in infants with CF

Maternal smoking during pregnancy increases the risk of recurrent wheezing during the first years of life (BAMSE)

BACKGROUND: Exposure to cigarette smoking during foetal and early postnatal life may have implications for lung health. The aim of this study was to assess the possible effects of such exposure in utero on lower respiratory disease in children up to two years of age. METHODS: A birth cohort of 4089 newborn infants was followed for two years using parental questionnaires. When the infant was two months old the parents completed a questionnaire on various lifestyle factors, including maternal smoking during pregnancy and after birth. At one and two years of age information was obtained by questionnaire on symptoms of allergic and respiratory diseases as well as on environmental exposures, particularly exposure to environmental tobacco smoke (ETS). Adjustments were made for potential confounders. RESULTS: When the mother had smoked during pregnancy but not after that, there was an increased risk of recurrent wheezing up to two years' age, OR(adj )= 2.2, (95% CI 1.3 – 3.6). The corresponding OR was 1.6, (95% CI 1.2 – 2.3) for reported exposure to ETS with or without maternal smoking in utero. Maternal smoking during pregnancy but no exposure to ETS also increased the risk of doctor's diagnosed asthma up to two years of age, OR(adj )= 2.1, (95% CI 1.2 – 3.7). CONCLUSION: Exposure to maternal cigarette smoking in utero is a risk factor for recurrent wheezing, as well as doctor's diagnosed asthma in children up to two yearsof age

Influence of Maternal Dysmetabolic Conditions During Pregnancy on Cardiovascular Disease

Pathogenic factors associated with maternal hypercholesterolemia, obesity, and diabetic conditions during pregnancy influence fetal development and predispose offspring to cardiovascular disease. Animal models have established cause–effect relationships consistent with epidemiological findings in humans and have demonstrated, in principle, that interventions before or during pregnancy can reduce or prevent pathogenic in utero programming. However, little is known about the mechanisms by which maternal dysmetabolic conditions enhance disease susceptibility in offspring. Identification of these mechanisms is rendered more difficult by the fact that programming effects in offspring may be latent and may require conventional risk factors and inherited genetic co-factors to become clinically manifest. Given the increasing prevalence of maternal risk factors, which is expected to lead to a wave of cardiovascular disease in the coming decades, and the length of prospective studies on developmental programming in humans, greater-than-usual emphasis on experimental models and translational studies is necessary