Plasma crosslinked fibrin polymers: quantitation based on tissue
plasminogen activator conversion to D-dimer and measurement in normal and
patients with acute thrombotic disorders
A Kornberg, CW Francis and VJ Marder
Department of Medicine, University of Rochester School of Medicine and
Dentistry, NY.
Plasma crosslinked fibrin polymers (XLFP) are formed as a result of in vivo
hemostatic activation and are elevated in thrombotic disease. We have
investigated the plasmic degradation of plasma XLFP in vitro to provide
information regarding the pattern of crosslinking and the composition of
degradation products. Plasma XLFP were identified by sodium dodecyl sulfate
(SDS)-agarose electrophoresis and Western blotting and quantitated by gel
scanning. D-dimer was measured by enzyme-linked immunosorbent assay and the
results were verified by SDS- polyacrylamide gel electrophoresis and
Western blotting of the digests. Complete degradation of XLFP occurred only
after supplementation of plasma with plasminogen (5 U/mL) and incubation
with recombinant tissue plasminogen activator (rt-PA), indicating that the
normal plasma plasminogen concentration limits plasmic degradation in
vitro. Gel electrophoresis showed that the principal terminal degradation
products of XLDP were fragments D, DD, and E, indicating that crosslinking
occurred primarily through gamma chain dimers. After adding a low
concentration of thrombin to plasma in vitro, XLFP increased progressively
before clotting, and the concentration correlated with the increase in the
D-dimer concentration after degradation (r = .98). Plasma XLFP and D-dimer
concentrations in plasmic digests were significantly elevated in patients
with stroke (150 +/- 83 micrograms/mL and 88 +/- 32 micrograms/mL),
myocardial infarction (217 +/- 110 micrograms/mL and 84 +/- 30
micrograms/mL), and venous thrombosis (187 +/- 80 micrograms/mL and 86 +/-
19 micrograms/mL) compared with normals (28 +/- 12 micrograms/mL and 25 +/-
7 micrograms/mL). There was a strong correlation between the plasma
concentration of XLFP and the D-dimer immunoreactivity of plasma after
plasmic degradation (r = .87). The results indicate that XLFP in plasma are
crosslinked primarily through gamma chains and degrade to fragment DD with
plasminogen activation. Also, the immunoreactivity of in vitro plasmic
digests of plasma reflects the concentration of XLFP and may provide a
useful indirect measure of in vivo hemostatic activation in patients with
thrombotic disease.
Volume 80,
Issue 3,
pp. 709-717,
08/01/1992
Copyright © 1992 by The American Society of Hematology
