Effect of ticlopidine on platelet-derived microparticles in patients with connective tissue diseases.

We evaluated the plasma concentrations of platelet activation markers and platelet-derived microparticles (PMP) in patients with connective tissue diseases complaining of peripheral circulation disorders (n = 16) and studied the effect of ticlopidine hydrochloride (ticlopidine) on PMP generation. There were significant differences in the levels of PMP and a platelet activation marker between before and after treatment with ticlopidine (PMP: 695 +/- 393 vs. 354 +/- 206/10(4) platelets, p < 0. 01; platelet CD63: 9.13 +/- 5.64 vs. 5.22 +/- 2.74%, p < 0.05). On the other hand, markers of vascular endothelium, such as vascular endothelium-derived small vesicles and serum thrombomodulin levels, were not affected by the administration of ticlopidine. Levels of cytokines and soluble adhesion molecules remained unchanged by ticlopidine administration. These findings suggest that ticlopidine may be useful for the inhibition of PMP-dependent vascular damage in patients with connective tissue diseases complaining of peripheral circulation disorders.