Behavior of plasminogen at the luminal surface of the normal and
deendothelialized rabbit aorta in vivo and in vitro
MW Hatton, SL Moar and M Richardson
Department of Pathology, McMaster University, Hamilton, Ontario, Canada.
The behavior of purified rabbit plasminogen at the luminal surface of the
uninjured and deendothelialized rabbit aorta has been studied in vivo and
in vitro. After intravenous injection, 125I-plasminogen associated rapidly
with the endothelium (approximately 0.1 pmol/cm2 at saturation) and passed
through to accumulate in the subendothelium. At two to 15 hours after
injection, 11 to 15 times more radioactivity was associated with the
subendothelium than with the endothelium. Removal of the endothelium by
balloon catheter led to a rapid adsorption of 125I-plasminogen by the
luminal surface of the vessel; saturation (9.1 pmol/cm2) was attained at
ten to 20 minutes after deendothelialization. Of the adsorbed plasminogen
(radioactivity), only 2% to 4% was associated with the adherent platelet
monolayer. Uptake of 125I- plasminogen by the deendothelialized vessel was
not significantly inhibited by epsilon-aminohexanoic acid whether injected
before or after the 125I-plasminogen. No evidence of plasmin activity at
the aorta surface was found from either transmission electron microscopy
studies or from amidolytic assays of plasminogen-saturated
deendothelialized aorta samples before or after urokinase treatment.
Balloon catheter treatment in vivo, however, generated significant
antiplasmin activity of the deendothelialized aorta surface. We conclude
that plasmin formed in vivo is probably inactivated by the antiplasmin
activity that is associated with the subendothelium.
Volume 71,
Issue 5,
pp. 1260-1267,
05/01/1988
Copyright © 1988 by The American Society of Hematology
