33 research outputs found

    Lung Volume, Breathing Pattern and Ventilation Inhomogeneity in Preterm and Term Infants

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    BACKGROUND: Morphological changes in preterm infants with bronchopulmonary dysplasia (BPD) have functional consequences on lung volume, ventilation inhomogeneity and respiratory mechanics. Although some studies have shown lower lung volumes and increased ventilation inhomogeneity in BPD infants, conflicting results exist possibly due to differences in sedation and measurement techniques. METHODOLOGY/PRINCIPAL FINDINGS: We studied 127 infants with BPD, 58 preterm infants without BPD and 239 healthy term-born infants, at a matched post-conceptional age of 44 weeks during quiet natural sleep according to ATS/ERS standards. Lung function parameters measured were functional residual capacity (FRC) and ventilation inhomogeneity by multiple breath washout as well as tidal breathing parameters. Preterm infants with BPD had only marginally lower FRC (21.4 mL/kg) than preterm infants without BPD (23.4 mL/kg) and term-born infants (22.6 mL/kg), though there was no trend with disease severity. They also showed higher respiratory rates and lower ratios of time to peak expiratory flow and expiratory time (t(PTEF)/t(E)) than healthy preterm and term controls. These changes were related to disease severity. No differences were found for ventilation inhomogeneity. CONCLUSIONS: Our results suggest that preterm infants with BPD have a high capacity to maintain functional lung volume during natural sleep. The alterations in breathing pattern with disease severity may reflect presence of adaptive mechanisms to cope with the disease process

    Pulmonary Function and Incident Bronchitis and Asthma in Children: A Community-Based Prospective Cohort Study

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    BACKGROUND: Previous studies revealed that reduction of airway caliber in infancy might increase the risks for wheezing and asthma. However, the evidence for the predictive effects of pulmonary function on respiratory health in children was still inconsistent. METHODS: We conducted a population-based prospective cohort study among children in 14 Taiwanese communities. There were 3,160 children completed pulmonary function tests in 2007 and follow-up questionnaire in 2009. Poisson regression models were performed to estimate the effect of pulmonary function on the development of bronchitis and asthma. RESULTS: After adjustment for potential confounders, pulmonary function indices consistently showed protective effects on respiratory diseases in children. The incidence rate ratios of bronchitis and asthma were 0.86 (95% CI 0.79-0.95) and 0.91 (95% CI 0.82-0.99) for forced expiratory volume in 1 second (FEV₁). Similar adverse effects of maximal mid-expiratory flow (MMEF) were also observed on bronchitis (RR = 0.73, 95% CI 0.67-0.81) and asthma (RR = 0.85, 95% CI 0.77-0.93). We found significant decreasing trends in categorized FEV₁ (p for trend = 0.02) and categories of MMEF (p for trend = 0.01) for incident bronchitis. Significant modification effects of traffic-related air pollution were noted for FEV₁ and MMEF on bronchitis and also for MMEF on asthma. CONCLUSIONS: Children with high pulmonary function would have lower risks on the development of bronchitis and asthma. The protective effect of high pulmonary function would be modified by traffic-related air pollution exposure

    Expression analysis of asthma candidate genes during human and murine lung development

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    <p>Abstract</p> <p>Background</p> <p>Little is known about the role of most asthma susceptibility genes during human lung development. Genetic determinants for normal lung development are not only important early in life, but also for later lung function.</p> <p>Objective</p> <p>To investigate the role of expression patterns of well-defined asthma susceptibility genes during human and murine lung development. We hypothesized that genes influencing normal airways development would be over-represented by genes associated with asthma.</p> <p>Methods</p> <p>Asthma genes were first identified via comprehensive search of the current literature. Next, we analyzed their expression patterns in the developing human lung during the pseudoglandular (gestational age, 7-16 weeks) and canalicular (17-26 weeks) stages of development, and in the complete developing lung time series of 3 mouse strains: A/J, SW, C57BL6.</p> <p>Results</p> <p>In total, 96 genes with association to asthma in at least two human populations were identified in the literature. Overall, there was no significant over-representation of the asthma genes among genes differentially expressed during lung development, although trends were seen in the human (Odds ratio, OR 1.22, confidence interval, CI 0.90-1.62) and C57BL6 mouse (OR 1.41, CI 0.92-2.11) data. However, differential expression of some asthma genes was consistent in both developing human and murine lung, e.g. <it>NOD1, EDN1, CCL5, RORA </it>and <it>HLA-G</it>. Among the asthma genes identified in genome wide association studies, <it>ROBO1</it>, <it>RORA, HLA-DQB1, IL2RB </it>and <it>PDE10A </it>were differentially expressed during human lung development.</p> <p>Conclusions</p> <p>Our data provide insight about the role of asthma susceptibility genes during lung development and suggest common mechanisms underlying lung morphogenesis and pathogenesis of respiratory diseases.</p

    Fetal and infant origins of asthma

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    Previous studies have suggested that asthma, like other common diseases, has at least part of its origin early in life. Low birth weight has been shown to be associated with increased risks of asthma, chronic obstructive airway disease, and impaired lung function in adults, and increased risks of respiratory symptoms in early childhood. The developmental plasticity hypothesis suggests that the associations between low birth weight and diseases in later life are explained by adaptation mechanisms in fetal life and infancy in response to various adverse exposures. Various pathways leading from adverse fetal and infant exposures to growth adaptations and respiratory health outcomes have been studied, including fetal and early infant growth patterns, maternal smoking and diet, children’s diet, respiratory tract infections and acetaminophen use, and genetic susceptibility. Still, the specific adverse exposures in fetal and early postnatal life leading to respiratory disease in adult life are not yet fully understood. Current studies suggest that both environmental and genetic factors in various periods of life, and their epigenetic mechanisms may underlie the complex associations of low birth weight with respiratory disease in later life. New well-designed epidemiological studies are needed to identify the specific underlying mechanisms. This review is focused on specific adverse fetal and infant growth patterns and exposures, genetic susceptibility, possible respiratory adaptations and perspectives for new studies

    Childhood asthma and early life exposure to indoor allergens, endotoxin and beta(1,3)-glucans.

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    BACKGROUND: Divergent results have been reported regarding early life exposure to indoor environmental agents and the risk of asthma and allergic sensitization later in life. OBJECTIVE: To assess whether early exposure to indoor allergens, beta(1,3)-glucans and endotoxin modifies the risk of allergic diseases at 10 years of age. METHODS: The concentrations of mite, cat and dog allergens, endotoxin and beta(1,3)-glucans were determined in dust from the homes of 260 two-year-old children with lung function measured at birth (tidal flow volume loops) in the Environment and Childhood Asthma study in Oslo. At 10 years, the health status was assessed in a follow-up study including a structured interview of the parents and an extended clinical examination. RESULTS: Cat and dog keeping at 2 years of age was reported in 6.5% and 5.5% of the families, respectively. Mite allergens were detected in only 4/260 dust samples. The adjusted odds ratio for asthma at age 10 was 1.20 (95% confidence interval: 1.01-1.43) and 1.22 (1.02-1.46) for bronchial hyperresponsiveness (BHR) per 10 microg/g dust increase in cat allergen exposure at 2 years of age. No association was seen with allergic sensitization. Moreover, endotoxin and beta(1,3)-glucan exposure did not modify the risk of asthma or allergic sensitization. None of the measured environmental factors were associated with lung function at 10 years of age or a relative change in lung function from birth. CONCLUSION: In a community with a low prevalence of pet keeping and low mite allergen levels, exposure to cat allergens early in life increased the risk of late childhood asthma and BHR, but not the risk of allergic sensitization. No risk modification was seen for dog allergens, endotoxin and beta(1,3)-glucans
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