Arteriosclerosis, Thrombosis, and Vascular Biology. 2006;26:1184
(Arteriosclerosis, Thrombosis, and Vascular Biology. 2006;26:1184.)
© 2006 American Heart Association, Inc.
Rapid Release of Active Tissue Factor From Human Arterial Smooth Muscle Cells Under Flow Conditions
Jan-Julius Stampfuss;
Petra Censarek;
Jens W. Fischer;
Karsten Schrör;
Artur-Aron Weber
Circulating tissue factor (TF) is an important determinant of
coronary thrombosis. Among other cell types, such as monocytes,
vascular smooth muscle cells (SMCs) are capable of releasing
TF. When studied under static conditions, SMCs do release TF,
but this process is slow and, thus, cannot explain the elevated
levels of circulating TF, as observed in patients with acute
coronary syndromes. The present study demonstrates that cultured
human mammary artery SMCs very rapidly (minutes) release active,
microparticle-bound TF when exposed to flow conditions. There
was a clear log-linear correlation between the shear rate (range
10 s
1 to 1500 s
1) and the procoagulant activity
of SMC perfusates. Flow-dependent release of TF was transient
(10 minutes) and did not measurably reduce cell surface TF content.
Interestingly, a time-dependent (t
1/2 30 minutes) re-exposure
of releasable TF was detected after a no-flow period. These
data demonstrate that SMCs may become a pathophysiologically
relevant source of TF that can be rapidly released into the
circulation in situations in which endothelial damage occurs
and SMCs come into a close contact with the flowing blood.
(Arterioscler Thromb Vasc Biol. 2006;26:e34e37.)
Key Words: tissue factor microparticles vascular smooth muscle cells flow