Effect of recombinant human DNase on alpha1-proteinase inhibitor function: an experimental approach to the combined clinical use of rhDNase and alpha1-PI in CF patients.
Chronic inflammation in cystic fibrosis (CF) airways leads to high concentrations of deoxyribonucleic acid (DNA) and neutrophil elastase (NE). Both play a major role in CF lung pathophysiology and are aims of new therapeutic approaches: rhDNase degrades highly viscosic DNA and alpha1-proteinase inhibitor (alpha1-PI) inhibits NE activity and thereby pulmonary inflammation and hypersecretion. Given the reports on increased sputum NE concentrations upon rhDNase inhalation, there is a rationale for a combined rhDNase/alpha1-PI treatment. With the question of whether a combined therapy is feasible, we first investigated in vitro whether incubation of CF sputum with rhDNase changes proteolytic and secretagogue activity of sputum supernatants and its inhibition by alpha1-PI. Next, we studied whether incubation of alpha1-PI with rhDNase impairs the inhibitory effect of alpha1-PI on proteolytic activity of NE and the inhibitory effect of alpha1-PI on NE-induced secretion from a human mucoepidermoid cell line. Incubation of CF sputum with rhDNase led to a twofold increase in sputum NE activity. Correspondingly, the inhibitory effect of alpha1-PI on sputum NE activity and on secretion induced by these sputum samples was significantly reduced by rhDNase. Preincubation of alpha1-PI with rhDNase significantly reduced the inhibitory effect of alpha1-PI on purified NE activity and on NE-induced secretion. However, this effect was limited to alpha1-PI concentrations lower than those achievable after inhalation. Therefore, impairment of alpha1-PI function by rhDNase is not likely to be relevant in vivo, provided that a sufficient dosage of alpha1-PI is inhaled.
Hansen
G
G
Martin-Luther-University, Children's Hospital, 06120 Halle, Germany.
Hoffjan
S
S
Mosler
K
K
Schuster
A
A
D000280:Administration, Inhalation; D000293:Adolescent; D000328:Adult; D002460:Cell Line / Q000187:drug effects; D002648:Child; D002669:Child Welfare; D003550:Cystic Fibrosis / Q000188:drug therapy* / Q000378:metabolism*; D003850:Deoxyribonuclease I / Q000494:pharmacology* / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical; D005260:Female; D006801:Humans; D019272:Leukocyte Elastase / Q000187:drug effects / Q000378:metabolism; D008297:Male; D010447:Peptide Hydrolases / Q000187:drug effects / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology* / Q000627:therapeutic use*; D013183:Sputum / Q000737:chemistry / Q000187:drug effects / Q000201:enzymology; D000515:alpha 1-Antitrypsin / Q000378:metabolism* / Q000494:pharmacology / Q000627:therapeutic use*
D011994:Recombinant Proteins; D000515:alpha 1-Antitrypsin; C085693:DNASE1 protein, human; D003850:Deoxyribonuclease I; D010447:Peptide Hydrolases; D019272:Leukocyte Elastase