Markers of endothelial and platelet status in patients with essential thrombocytemia and polycythemia vera

Vascular complications are the main cause of morbidity in polycythemia vera (PV) and essential thrombocythemia (ET). To investigate plasma concentrations of soluble P-selectin (sP-Sel.), soluble E-selectin (sE-Sel.) and soluble thrombomodulin (sTM) in relation to the presence of thromboembolic events 38 patients with Chronic Myeloproliferative Disorders (CMD) (14 PV pts and 24 ET pts), 15 age - matched controls and 15 patients with secondary thrombocytosis were studied. Plasma levels of P-Sel., E-Sel. and TM were significantly increased in the group of patients as compared with control subjects (respectively p < 0.001, p < 0.04 and p < 0.01). sP-Sel. levels showed no significant difference between the patients and those with secondary thrombocytosis. No difference in sP-sel levels were also observed between subgroups of CMD patients with and without vascular complications. However, among patients with ET, those with thrombosis had higher sP-Sel levels than those without thrombosis (1.177 +/- 110.48 ng/ml vs 816.25 +/- 99.27 ng/ml). High levels of sE-Sel and sTM were found in CMD patients (71.93 +/- 39.08 ng/ml and 35.81 +/- 20.79 ng/ml, respectively). Plasma sE-Sel. concentration was significantly higher in CMD patients with thrombosis than that in CMD patients without thrombosis (p < 0.001). There was no difference in sTM concentration between two groups. These findings indicate that sustained endothelium and platelet activation is present in patients with ET and PV and it might contribute to the pathogenesis of thromboembolic events in these patients.