Formation of polymorphonuclear leukocyte elastase: alpha 1 proteinase inhibitor complex and A alpha (1-21) fibrinopeptide in human blood stimulated with the calcium ionophore A23187. A model to characterize inhibitors of polymorphonuclear leukocyte elastase.
Incubation of human blood with the secretagogue A23187 resulted in the formation of increased plasma concentrations of polymorphonuclear leukocyte (PMN) elastase: alpha 1 proteinase inhibitor (PMNE:alpha 1 PI) complex as well as A alpha(1-21) fibrinopeptide [A alpha(1-21)]. The formation of these species was both time and A23187 concentration dependent. Using a sandwich ELISA and a radioimmunoassay, we determined the comparative potencies of several compounds to inhibit the formation of PMNE: alpha 1 PI complexes and A alpha(1-21), respectively. L-658,758, a substituted cephalosporin, essentially irreversible elastase inhibitor, inhibited the formation of PMNE: alpha 1 PI and A alpha(1-21) with IC50 values of 38 and 15 microM, respectively. L-683,845, a monocyclic beta-lactam, was much more potent against isolated PMNE than L-658,758. However in this system it was approximately equivalent to L-658,758 with an IC50 of 15 microM against both species. ICI-200,880, a competitive slow-binding elastase inhibitor, was significantly less potent to inhibit A alpha(1-21), having an IC50 of 75 microM, while Declaben, a reversible noncompetitive inhibitor, was inactive at concentrations as great as 200 microM. We propose that evaluating inhibitors in the complex milieu of blood will provide a useful method to predict their therapeutic potential in vivo.
Pacholok
S G
SG
Merck Research Laboratories, Rahway, NJ 07065, USA.
Davies
P
P
Dorn
C
C
Finke
P
P
Hanlon
W A
WA
Mumford
R A
RA
Humes
J L
JL
D000001:Calcimycin / Q000494:pharmacology*; D002511:Cephalosporins; D002723:Chlorobenzoates / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005338:Fibrin Fibrinogen Degradation Products / Q000096:biosynthesis*; D006801:Humans; D066298:In Vitro Techniques; D019272:Leukocyte Elastase / Q000037:antagonists & inhibitors* / Q000097:blood; D009504:Neutrophils / Q000187:drug effects* / Q000201:enzymology*; D009842:Oligopeptides / Q000494:pharmacology; D010196:Pancreatic Elastase / Q000037:antagonists & inhibitors* / Q000097:blood; D011759:Pyrrolidines / Q000494:pharmacology; D000515:alpha 1-Antitrypsin / Q000096:biosynthesis*
C053898:Aalpha 1-21 peptide; D002511:Cephalosporins; D002723:Chlorobenzoates; D005338:Fibrin Fibrinogen Degradation Products; D009842:Oligopeptides; D011759:Pyrrolidines; D000515:alpha 1-Antitrypsin; C069695:ICI 200880; C065332:L 658758; D000001:Calcimycin; C053557:lodelaben; D010196:Pancreatic Elastase; D019272:Leukocyte Elastase