Intravenous recombinant secretory leukoprotease inhibitor augments antineutrophil elastase defense.
Secretory leukoprotease inhibitor (SLPI), a 12-kDa serine antiprotease, normally protects the upper airway epithelial surface from attack by neutrophil elastase (NE). In the context that a variety of inflammatory lung diseases are characterized by large neutrophil burdens with resultant high levels of NE in the lung, recombinant SLPI (rSLPI), a molecule identical to natural SLPI, may be an effective means to augment the anti-NE protective screen of the lung. To determine whether intravenous rSLPI will augment respiratory tract and epithelial surface levels of SLPI and anti-NE capacity, rSLPI was administered intravenously to sheep and SLPI levels were quantified in plasma, lung lymph (as a measure of lung interstitial levels), lung epithelial lining fluid (ELF), and urine. rSLPI (1 g) was administered over 10 min, and after 30 min plasma levels of SLPI were 8 microM and decreased with a half-life of 1.8 h. Lymph SLPI levels paralleled the plasma levels: 4 h after infusion the lymph-to-plasma ratio was 0.8. ELF SLPI levels paralleled the lymph levels: 4 h after infusion the ELF-to-lymph ratio was 0.3. Western analysis demonstrated intact SLPI in lymph and ELF, and functional analysis showed increases in lymph and ELF anti-NE capacity that paralleled the levels of SLPI. As might be expected from a protein with a molecular mass of 12 kDa, urine excretion was high, with 20% of the SLPI excreted over 5 h. However, if the rate of infusion was slowed, SLPI excretion decreased significantly, with a 3-h infusion associated with 9% excretion and a 12-h infusion associated with less than 0.2% excretion.(ABSTRACT TRUNCATED AT 250 WORDS)
Birrer
P
P
Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892.
McElvaney
N G
NG
Gillissen
A
A
Hoyt
R F
RF
Bloedow
D C
DC
Hubbard
R C
RC
Crystal
R G
RG
D000818:Animals; D015153:Blotting, Western; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D004848:Epithelium / Q000378:metabolism; D005260:Female; D007275:Injections, Intravenous; D008168:Lung / Q000378:metabolism; D009504:Neutrophils / Q000187:drug effects / Q000201:enzymology*; D010196:Pancreatic Elastase / Q000378:metabolism*; D053491:Proteinase Inhibitory Proteins, Secretory; D011506:Proteins; D011994:Recombinant Proteins / Q000494:pharmacology; D015842:Serine Proteinase Inhibitors / Q000008:administration & dosage / Q000494:pharmacology* / Q000652:urine; D012756:Sheep
D053491:Proteinase Inhibitory Proteins, Secretory; D011506:Proteins; D011994:Recombinant Proteins; D015842:Serine Proteinase Inhibitors; D010196:Pancreatic Elastase