CXC chemokines and antimicrobial peptides in rhinovirus-induced experimental asthma exacerbations.

RATIONALE: Rhinoviruses (RVs) are the major triggers of asthma exacerbations. We have shown previously that lower respiratory tract symptoms, airflow obstruction, and neutrophilic airway inflammation were increased in experimental RV-induced asthma exacerbations. OBJECTIVES: We hypothesized that neutrophil-related CXC chemokines and antimicrobial peptides are increased and related to clinical, virologic, and pathologic outcomes in RV-induced exacerbations of asthma. METHODS: Protein levels of antimicrobial peptides (SLPI, HNP 1-3, elafin, and LL-37) and neutrophil chemokines (CXCL1/GRO-α, CXCL2/GRO-ß, CXCL5/ENA-78, CXCL6/GCP-2, CXCL7/NAP-2, and CXCL8/IL-8) were determined in bronchoalveolar lavage (BAL) fluid of 10 asthmatics and 15 normal controls taken before, at day four during and 6 weeks post-experimental infection. RESULTS: BAL HNP 1-3 and Elafin were higher, CXCL7/NAP-2 was lower in asthmatics compared with controls at day 4 (P = 0.035, P = 0.048, and P = 0.025, respectively). BAL HNP 1-3 and CXCL8/IL-8 were increased during infection (P = 0.003 and P = 0.011, respectively). There was a trend to increased BAL neutrophils at day 4 compared with baseline (P = 0.076). BAL HNP 1-3 was positively correlated with BAL neutrophil numbers at day 4. There were no correlations between clinical parameters and HNP1-3 or IL-8 levels. CONCLUSIONS: We propose that RV infection in asthma leads to increased release of CXCL8/IL-8, attracting neutrophils into the airways where they release HNP 1-3, which further enhances airway neutrophilia. Strategies to inhibit CXCL8/IL-8 may be useful in treatment of virus-induced asthma exacerbations.

Rhinovirus induces MUC5AC in a human infection model and in vitro via NF-κB and EGFR pathways.

Rhinovirus (RV) infections are the major cause of asthma exacerbations, the major cause of morbidity and mortality in asthma. MUC5AC is the major mucin produced by bronchial epithelial cells. Whether RV infection upregulates MUC5AC in vivo is unknown and the molecular mechanisms involved are incompletely understood. We investigated RV induction of MUC5AC in vivo and in vitro to identify targets for development of new therapies for asthma exacerbations. RV infection increased MUC5AC release in normal and asthmatic volunteers experimentally infected with RV-16, and in asthmatic, but not normal, subjects, this was related to virus load. Bronchial epithelial cells were confirmed a source of MUC5AC in vivo. RV induction of MUC5AC in bronchial epithelial cells in vitro occurred via nuclear factor-κB-dependent induction of matrix metalloproteinase-mediated transforming growth factor-α release, thereby activating an epidermal growth factor receptor-dependent cascade culminating, via mitogen-activated protein kinase activation, in specificity protein-1 transactivation of the MUC5AC promoter. RV induction of MUC5AC may be an important mechanism in RV-induced asthma exacerbations in vivo. Revealing the complex serial signalling cascade involved identifies targets for development of pharmacologic intervention to treat mucus hypersecretion in RV-induced illness.

Data compression in a textual medical application.

On-line storage of textual data can represent a significant expense even with today's lower storage costs. This paper presents a hybrid compression scheme designed for rapid decoding and retrieval in a medical data base application. Utilizing this method, a 60% reduction of the space required has been obtained.