title: Nitric oxide production by pulmonary leukocytes from induced sputum in patients with asthma and its effect on epithelial cell viability.
abstract: BACKGROUND
  Nitric oxide (NO) is one of many factors potentially involved in lung remodeling in asthma. The aim of the study was to assess the effect of pulmonary leukocytes from patients with bronchial asthma on alveolar epithelial cell damage in relation to NO production.
  
  
  METHODS
  Induced sputum samples were obtained from 25 patients with bronchial asthma and 10 healthy volunteers. Twelve asthmatics were on inhaled corticosteroid treatment and 13 were corticosteroid free. Type II-like alveolar epithelial (A549) cells were cultured for 48 h in the presence of cell-free media from a 24-h culture of leukocytes obtained from the induced sputa (IS-Su). The level of NO was measured in supernatants from the cell cultures and the viability of the A549 cells was established.
  
  
  RESULTS
  The levels of NO in IS-Su from corticosteroid-free asthmatics were significantly higher (p = 0.001) than those in IS-Su from healthy controls. Furthermore, NO production by A549 cells exposed to IS-Su from steroid-free asthmatics (group A) was significantly higher than that from asthmatics on corticosteroid therapy (group cA) as well as from healthy controls (p = 0.01 and p = 0.001, respectively). Lower viability of the epithelial cells exposed to IS-Su was observed in group A compared with controls (median: 72% vs. 97.5%; p < 0.001). In addition, a negative correlation (R(S) = - 0.706, p < 0.001) was found between the levels of NO produced by pulmonary leukocytes and the viability of epithelial cells.
  
  
  CONCLUSIONS
  The results suggest that in the course of asthma, pulmonary leukocytes may interact with alveolar epithelial cells by inducing an excessive production of NO which, in turn, may contribute to epithelium impairment.
authors.affiliation: Laboratory of Virology, Institute of Immunology and Experimental Therapy, Polish Academy of Science, Wrocław, Poland.
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Bieńkowska-Haba
authors.forename: Jerzy
authors.initials: J
authors.lastname: Liebhart
authors.forename: Monika
authors.initials: M
authors.lastname: Cembrzyńska-Nowak
mesh_terms: D000328:Adult; D000368:Aged; D001249:Asthma / Q000276:immunology / Q000378:metabolism*; D002450:Cell Communication; D002460:Cell Line; D002470:Cell Survival; D017077:Culture Media, Conditioned / Q000494:pharmacology; D005260:Female; D006801:Humans; D007962:Leukocytes / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism*; D011650:Pulmonary Alveoli / Q000166:cytology*; D020545:Respiratory Mucosa / Q000166:cytology*; D013183:Sputum / Q000166:cytology
chemical_list: D017077:Culture Media, Conditioned; D009569:Nitric Oxide