Extracellular metabolites of Pseudomonas aeruginosa produce bronchoconstriction by different mechanisms.
Bacterial supernatants (BS) obtained from broth cultures of Pseudomonas aeruginosa cause bronchoconstriction in sheep, suggesting that BS contain proinflammatory metabolites. In this study we investigated the mechanism(s) responsible for this bronchial effect. BS were obtained from 48 h cultures and sterilized by filtration. Sheep (n = 6) were intubated and swallowed an esophageal balloon for the measurement of specific lung resistance (SRL). Aerosols of BS (3 ml total) immediately increased SRL (541%). Neither aerosolized broth (control) nor inhaled endotoxin in excess of that contained in the BS had an effect. BS challenges were repeated on separate occasions except that the sheep were treated 30 min before challenge with the anticholinergic agent atropine (0.2 mg/kg, intravenously); the anti-allergic agent nedocromil (1 mg/kg, aerosol); the histamine H1 antagonist chlorpheniramine (2 mg/kg); or the bradykinin (BK) B2 receptor antagonists NPC-567 (5 mg/ml, aerosol) or NPC-17761 (1 mg/ml aerosol). The results showed that greater than 90% protection (p < 0.05) was achieved when the animals were pretreated with atropine, nedocromil sodium, or either of the two BK antagonists, but only 27 +/- 21% protection was seen with chlorpheniramine pretreatment. These findings are characteristic of a BK-mediated response. Analysis of bronchoalveolar lavage fluid obtained before and after BS challenge confirmed that i-kinins, but not histamine, increased (p < 0.05) from 61 +/- 7 to 304 +/- 55 pg/ml. Control (broth) challenges produced no such change. To identify the metabolites involved, we tested the effects of aerosolizing two suspected components of BS, 1-hydroxyphenazine (1-HP) and pyocyanine (PYO) in five sheep.(ABSTRACT TRUNCATED AT 250 WORDS)
Forteza
R
R
Division of Pulmonary Disease, University of Miami, Mount Sinai Medical Center, Miami Beach, Florida 33140.
Lauredo
I T
IT
Burch
R
R
Abraham
W M
WM
D000280:Administration, Inhalation; D000336:Aerosols; D000403:Airway Resistance / Q000187:drug effects; D000818:Animals; D001285:Atropine / Q000627:therapeutic use; D001920:Bradykinin / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors / Q000627:therapeutic use; D065168:Bradykinin Receptor Antagonists; D001982:Bronchial Diseases / Q000139:chemically induced* / Q000150:complications / Q000188:drug therapy / Q000503:physiopathology; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D002744:Chlorpheniramine / Q000627:therapeutic use; D003251:Constriction, Pathologic / Q000139:chemically induced / Q000150:complications / Q000188:drug therapy / Q000503:physiopathology; D004353:Drug Evaluation, Preclinical; D004731:Endotoxins / Q000494:pharmacology*; D005260:Female; D007249:Inflammation; D007705:Kinins / Q000032:analysis; D017835:Nedocromil / Q000627:therapeutic use; D010619:Phenazines / Q000378:metabolism / Q000494:pharmacology*; D011292:Premedication; D011550:Pseudomonas aeruginosa / Q000378:metabolism; D011710:Pyocyanine / Q000378:metabolism / Q000494:pharmacology*; D012756:Sheep
D000336:Aerosols; D065168:Bradykinin Receptor Antagonists; D004731:Endotoxins; D007705:Kinins; D010619:Phenazines; D017835:Nedocromil; C083947:NPC 17761; D002744:Chlorpheniramine; C050093:1-hydroxyphenazine; D001285:Atropine; D011710:Pyocyanine; C053010:NPC 567; D001920:Bradykinin