Premium
Plasminogen activator inhibitor (PAI‐1) in plasma and platelets
Author(s) -
Booth N. A.,
Simpson A. J.,
Croll A.,
Bennett B.,
MacGregor I. R.
Publication year - 1988
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/j.1365-2141.1988.tb02490.x
Subject(s) - platelet , medicine , chemistry , plasminogen activator inhibitor 1 , endocrinology , plasminogen activator , mean platelet volume , lysis , immunology , biochemistry
The distribution of PAI‐1 in the plasma and platelets of normal individuals and of patients with platelet abnormalities was studied. An ELISA, capable of measuring PAI‐1 in plasma at 1.5 ng/ml, and a functional assay of t‐PA inhibition were used to assay platelet‐free plasma (PFP), platelet‐rich plasma in which the platelets were lysed (PRP) and serum. The PAI‐1 concentration of normal PFP was 21.0 ± 7.2 ng/ml (mean ± SD) and those of PRP and serum were 282.6 ± 68.0 and 270.3 ± 71.9 ng/ml. The concentration of PAI‐1 in PRP was proportional to the platelet count with 0.67 ± 0.18 ng/10 6 platelets. Patients with thrombocy‐topenia had approximately normal PAI‐1 concentrations in PFP; the extremely low concentrations in serum or PRP reflected the platelet count. A patient with grey platelet syndrome showed a comparable pattern, confirming that PAI‐1 occurs in the platelet α‐granules and indicating that the plasma concentration of PAI‐1 is independent of the platelet pool of PAI‐1. The median inhibitory activities towards t‐PA were 1.6, 8.7 and 8.3 units/ml in normal PFP. PRP and serum respectively. PAI‐1 in PFP had a median specific activity (units/mg PAI‐1) about 5‐fold higher than platelet PAI‐1. Plasma and platelets represent two distinct pools of PAI‐1, both of which should be considered in studies on the relationship between circulating PAI‐1 and thrombotic disease.