Platelet Activation Markers in Patients with Venous Thromboembolism without Predisposing Factors

Abstract

A constant in vitro hypersensitivity of platelets (adenosine diphosphate) has been suggested as a risk factor for arterial and even venous thrombosis. Our aim was to determine phenotypic and functional alterations of platelets by flow cytometry as potential prothrombotic risk factors in patients with a history of unexplained spontaneous venous thrombosis. Forty-nine patients with a history of spontaneous venous thrombosis and no inherited or acquired thrombophilic risk factors were compared with a reference group of 39 healthy volunteers. Flow cytometry (FACS) was used to analyze the surface expression of CD62 (P-selectin) and CD63 in nonactivated platelets and after in vitro stimulation with adenosine diphosphate and thrombin receptor activator peptide 6. Mean fluorescence intensity of CD62 and CD63 surface expression as well as percentage of CD62 and CD63 positive cells and binding index differed in patients with a history of thrombosis compared with the reference group, but failed to reach statistical significance. Similar results were observed after in vitrostimulation with adenosine diphosphate and thrombin receptor activator peptide 6. In conclusion, the expression of CD62 and CD63 of resting and in vitro activated platelets could not be established as a risk factor for spontaneous venous thromboembolism.

Endothelial dysfunction in patients with spontaneous venous thromboembolism

“…The latter finding is in agreement with a recent study that failed to show, in patients with spontaneous VTE, any significant in vivo platelet activation. 36 The lack of in vivo platelet activation in patients with spontaneous VTE suggests that their defect is primarily endothelial; this is consistent with our previous observation that in vivo platelet hyperactivity is the consequence of associated risk factors, such as diabetes, hypercholesterolemia or smoking, and not of the vascular damage itself.…”

Activated platelets as a possible early marker to predict clinical efficacy of leukocytapheresis in severe ulcerative colitis patients

“…10,16,17 In resting platelets, CD63 (a 40-to 55-kDa glycoprotein) is contained in a lysosome granule, while CD62-P (a 140-kDa glycoprotein) is contained in the alpha granule of platelets. CD63 and CD62-P are se- Data are presented as the means ± SD LCAP, leukocytapheresis; N.S., not significant * P < 0.05 was considered significant creted and appear on the surface of the platelet membrane when platelets are activated by external stimulation such as contact with foreign materials.…”

Relationship Between Mean Platelet Volume and Pulmonary Embolism in Patients With Deep Vein Thrombosis

“…We evaluated the platelet reactivity by measuring MPV in patients with DVT. Support for the role of platelet abnormalities contributing to the pathophysiology of VTE is evident from reports of increased MPV in VTE such as DVT and PE [4,[14][15][16][17].…”

“…In most cases PE is a major complication of DVT and shares the same predisposing factors [2]. Platelets have an important role in the pathogenesis of atherothrombosis and venous thrombosis [3,4]. Mean platelet volume (MPV) is a simple and easy marker reflecting platelet reactivity or activation [5,6].…”