Passive smoking impairs histone deacetylase-2 in children with severe asthma.

BACKGROUND: Parental smoking is known to worsen asthma symptoms in children and to make them refractory to asthma treatment, but the molecular mechanism is unclear. Oxidative stress from tobacco smoke has been reported to impair histone deacetylase-2 (HDAC2) via phosphoinositide-3-kinase (PI3K)/Akt activation and, thus, to reduce corticosteroid sensitivity. The aim of this study was to investigate passive smoking-dependent molecular abnormalities in alveolar macrophages (AMs) by comparing passive smoke-exposed children and non-passive smoke-exposed children with uncontrolled severe asthma. METHODS: BAL fluid (BALF) was obtained from 19 children with uncontrolled severe asthma (10 non-passive smoking-exposed subjects and nine passive smoking-exposed subjects), and HDAC2 expression/activity, Akt/HDAC2 phosphorylation levels, and corticosteroid responsiveness in AMs were evaluated. RESULTS: Parental smoking reduced HDAC2 protein expression by 54% and activity by 47%, with concomitant enhancement of phosphorylation of Akt1 and HDAC2. In addition, phosphorylation levels of Akt1 correlated positively with HDAC2 phosphorylation levels and negatively with HDAC2 activity. Furthermore, passive smoke exposure reduced the inhibitory effects of dexamethasone on tumor necrosis factor-α-induced CXCL8 release in AMs. There were relatively higher neutrophil counts and CXCL8 concentrations in BALF and lower Asthma Control Test scores compared with non-passive smoke-exposed children with uncontrolled severe asthma. CONCLUSIONS: Passive smoking impairs HDAC2 function via PI3K signaling activation, which could contribute to corticosteroid-insensitive inflammation in children with severe asthma. This novel mechanism will be a treatment target in children with severe asthma and stresses the need for a smoke-free environment for asthmatic children.

Screening for gastric premalignant lesions with narrow band imaging, white light and updated Sydney protocol or both?

BACKGROUND: Narrow band imaging (NBI) can accurately discriminate gastritis but premalignant lesions (PMLs) are difficult to detect. AIMS: The purpose of this study was to compare white light endoscopy (WLE) and histopathologic findings using the updated Sydney protocol (USP) with NBI and targeted biopsies (TB). METHODS: One hundred nineteen symptomatic patients referred for upper GI endoscopy were included in this prospective open study. All patients were assessed for gastritis and PMLs using WLE and NBI by two endoscopists selected in a random manner. Biopsies were taken according to USP and targeted from any area suspicious for PML. Imaging and histological findings between protocols were compared. RESULTS: In total 45 patients (38 %) had atrophy of whom 39 (32.7 %) were detected with WLE-USP and 28 (23.5 %) with NBI-TB (p = 0.03), 25 (21 %) had intestinal metaplasia (IM) of whom 19 (16 %) were detected with WLE-USP and 18 (15.1 %) with NBI-TB (p = 0.7) and 14 (12 %) had dysplasia of whom 12 (10 %) were detected with WLE-USP and 7 (7 %) with NBI-TB (p = 0.5), and 1 (0.8 %) case of gastric cancer only detected with WLE-USP. Accuracies for atrophy and IM were 93 and 90 % for the WLE-USP and 80 and 82 % for NBI-TB. The NBI-TB detected six cases of atrophy (13 %), 5 (20 %) of IM, and 2 (14 %) of dysplasia missed by WLE-USP as agreement was moderate. Accuracies of the NBI patterns for body and antral gastritis were 80 and 84 %. CONCLUSIONS: In a non high-risk population NBI-TB has less accuracy in detecting premalignant lesions compared to WLE-USP. However, it may be used as an important and easy-to-use complementary method which increases overall detectability for gastric premalignant lesions.

Sputum inflammatory phenotypes are not stable in children with asthma.

BACKGROUND: Two distinct, stable inflammatory phenotypes have been described in adults with asthma: eosinophilic and non-eosinophilic. Treatment strategies based on these phenotypes have been successful. This study evaluated sputum cytology in children with asthma to classify sputum inflammatory phenotypes and to assess their stability over time. METHODS: Sputum induction was performed in 51 children with severe asthma and 28 with mild to moderate asthma. Samples were classified as eosinophilic (>2.5% eosinophils), neutrophilic (>54% neutrophils); mixed granulocytic (>2.5% eosinophils, >54% neutrophils); or paucigranulocytic (≤2.5% eosinophils, ≤54% neutrophils). Sputum induction was repeated every 3 months in children with severe asthma (n=42) over a 1-year period and twice in mild to moderate asthma (n=17) over 3-6 months. RESULTS: 62 children (78%) had raised levels of inflammatory cells in at least one sputum sample. In the longitudinal analysis 37 of 59 children (63%) demonstrated two or more phenotypes. Variability in sputum inflammatory phenotype was observed in both the severe and the mild to moderate asthma groups. Change in phenotype was not related to change in inhaled corticosteroid (ICS) dose or asthma control, nor was it reflected in a change in exhaled nitric oxide (FE(NO)). 24 children (41%) fulfilled the criteria for non-eosinophilic asthma on one occasion and eosinophilic on another. There were no differences in severity, asthma control, atopy, ICS dose or forced expiratory volume in 1 s between those who were always non-eosinophilic and those always eosinophilic. CONCLUSION: Raised levels of inflammatory cells were frequently found in children with asthma of all severities. Sputum inflammatory phenotype was not stable in children with asthma.

Pediatric severe asthma is characterized by eosinophilia and remodeling without T(H)2 cytokines.

BACKGROUND: The pathology of pediatric severe therapy-resistant asthma (STRA) is little understood. OBJECTIVES: We hypothesized that STRA in children is characterized by airway eosinophilia and mast cell inflammation and is driven by the T(H)2 cytokines IL-4, IL-5, and IL-13. METHODS: Sixty-nine children (mean age, 11.8 years; interquartile range, 5.6-17.3 years; patients with STRA, n = 53; control subjects, n = 16) underwent fiberoptic bronchoscopy, bronchoalveolar lavage (BAL), and endobronchial biopsy. Airway inflammation, remodeling, and BAL fluid and biopsy specimen T(H)2 cytokines were quantified. Children with STRA also underwent symptom assessment (Asthma Control Test), spirometry, exhaled nitric oxide and induced sputum evaluation. RESULTS: Children with STRA had significantly increased BAL fluid and biopsy specimen eosinophil counts compared with those found in control subjects (BAL fluid, P < .001; biopsy specimen, P < .01); within the STRA group, there was marked between-patient variability in eosinophilia. Submucosal mast cell, neutrophil, and lymphocyte counts were similar in both groups. Reticular basement membrane thickness and airway smooth muscle were increased in patients with STRA compared with those found in control subjects (P < .0001 and P < .001, respectively). There was no increase in BAL fluid IL-4, IL-5, or IL-13 levels in patients with STRA compared with control subjects, and these cytokines were rarely detected in induced sputum. Biopsy IL-5(+) and IL-13(+) cell counts were also not higher in patients with STRA compared with those seen in control subjects. The subgroup (n = 15) of children with STRA with detectable BAL fluid T(H)2 cytokines had significantly lower lung function than those with undetectable BAL fluid T(H)2 cytokines. CONCLUSIONS: STRA in children was characterized by remodeling and variable airway eosinophil counts. However, unlike in adults, there was no neutrophilia, and despite the wide range in eosinophil counts, the T(H)2 mediators that are thought to drive allergic asthma were mostly absent.

Association of hypothalamic-pituitary-adrenal axis-related polymorphisms with stress in asthmatic children on inhaled corticosteroids.

OBJECTIVE: Long-term treatment of asthmatic children with low and moderate doses of inhaled corticosteroids (ICS) may result in mild adrenal suppression. Various associations have been shown between adrenal reactivity and single nucleotide polymorphisms (SNPs) related to the hypothalamic-pituitary-adrenal (HPA) axis. We aimed to investigate the genetic contribution of four HPA axis-related SNPs to the individual stress response when on ICS. METHODS: The low dose Synacthen test was performed in 62 asthmatic children (43 males, median age 7.9 years) before and after 3 months of treatment with inhaled fluticasone (200 µg/day) or budesonide (400 µg/day). The SNPs determined were: rs1876828 and rs242941 in the corticotropin-releasing hormone receptor 1 (CRHR1) gene, T(-2C) in the promoter region of the melanocortin receptor 2 (MC2R) gene and BclI restriction fragment length polymorphsism in the glucocorticoid receptor (GR) gene. RESULTS: Homozygotes for the variant rs242941 (TT) demonstrated a delayed cortisol response after treatment with ICS compared to heterozygotes (GT) (p = 0.033) and those with the wild-type (GG) genotype (p = 0.018). Homozygotes for the variant rs1876828 (AA) manifested lower baseline cortisol levels before treatment (p = 0.009) compared to the GG genotype and delayed cortisol response after treatment compared to the GA genotype (p = 0.05). BclI heterozygotes for the G allele (GC) demonstrated higher basal cortisol levels before and after treatment with ICS compared to homozygotes (CC) (p = 0.024, p = 0.018). Three SNP interactions were associated with serum cortisol levels. CONCLUSION: There is evidence of a contribution of HPA axis-related genetic variation to the stress response of asthmatic children on ICS. The clinical importance of this finding needs further elucidation.

Distinct patterns of inflammation in the airway lumen and bronchial mucosa of children with cystic fibrosis.

BACKGROUND: Studies in cystic fibrosis (CF) generally focus on inflammation present in the airway lumen. Little is known about inflammation occurring in the airway wall, the site ultimately destroyed in end-stage disease. OBJECTIVE: To test the hypothesis that inflammatory patterns in the lumen do not reflect those in the airway wall of children with CF. METHODS: Bronchoalveolar lavage (BAL) fluid and endobronchial biopsies were obtained from 46 children with CF and 16 disease-free controls. BAL cell differential was assessed using May-Gruenwald-stained cytospins. Area profile counts of bronchial tissue immunopositive inflammatory cells were determined. RESULTS: BAL fluid from children with CF had a predominance of neutrophils compared with controls (median 810×10(3)/ml vs 1×10(3)/ml, p<0.0001). In contrast, subepithelial bronchial tissue from children with CF was characterised by a predominance of lymphocytes (median 961 vs 717 cells/mm(2), p=0.014), of which 82% were (CD3) T lymphocytes. In chest exacerbations, BAL fluid from children with CF had more inflammatory cells of all types compared with those with stable disease whereas, in biopsies, only the numbers of lymphocytes and macrophages, but not of neutrophils, were higher. A positive culture of Pseudomonas aeruginosa was associated with higher numbers of T lymphocytes in subepithelial bronchial tissue (median 1174 vs 714 cells/mm(2), p=0.029), but no changes were seen in BAL fluid. Cell counts in BAL fluid and biopsies were positively correlated with age but were unrelated to each other. CONCLUSION: The inflammatory response in the CF airway is compartmentalised. In contrast to the neutrophil-dominated inflammation present in the airway lumen, the bronchial mucosa is characterised by the recruitment and accumulation of lymphocytes.

Development of the bronchial epithelial reticular basement membrane: relationship to epithelial height and age.

BACKGROUND: The bronchial epithelium and underlying reticular basement membrane (RBM) have a close spatial and functional inter-relationship and are considered an epithelial-mesenchymal trophic unit (EMTU). An understanding of RBM development is critical to understanding the extent and time of appearance of its abnormal thickening that is characteristic of asthma. METHODS: RBM thickness and epithelial height were determined in histological sections of cartilaginous bronchi obtained postmortem from 47 preterm babies and infants (median age 40 weeks gestation (22 weeks gestation-8 months)), 40 children (2 years (1 month-17 years)) and 23 adults (44 (17-90) years) who had died from non-respiratory causes, and had no history of asthma. RESULTS: The RBM was visible by light microscopy at 30 weeks gestation. RBM thickness increased in successive age groups in childhood; in infants (r=0.63, p<0.001) and in children between 1 month and 17 years (r=0.82, p<0.001). After 18 years, RBM thickness decreased with increasing age (r=-0.42, p<0.05). Epithelial height showed a similar relationship with age, a positive relationship from preterm to 17 years (r=0.50, p<0.001) and a negative relationship in adulthood (r=-0.84, p<0.0001). There was a direct relationship between epithelial height and RBM thickness (r=0.6, p<0.001). CONCLUSIONS: The RBM in these subjects was microscopically identifiable by 30 weeks gestation. It thickened during childhood and adolescence. In adults, there was either no relationship with age, or a slow reduction in thickness in older age. Developmental changes of RBM thickness were accompanied by similar changes in epithelial height, supporting the close relationship between RBM and epithelium within the EMTU.