Elevated Plasma Levels of P‐Selectin Glycoprotein Ligand‐1 Positive Microvesicles in Patients with Unprovoked Venous Thromboembolism

Abstract

Background<br> Microvesicles (MVs) express antigens from their parental cells and have a highly procoagulant surface. Animal studies suggest that P‐Selectin Glycoprotein Ligand‐1 positive (PSGL‐1+) MVs play a role in the pathogenesis of venous thromboembolism (VTE).<p>

Objective<br> The aim of this study was to determine plasma levels, the cellular origin and the morphological characteristics of PSGL‐1+ MVs in patients with unprovoked VTE.<p>

Methods<br> We conducted a population based case‐control study in 20 patients with a history of unprovoked VTE and 20 age‐ and sex‐matched healthy controls recruited from the general population. Plasma levels, the cellular origin and the morphological characteristics of PSGL‐1+ MVs was evaluated using flow cytometry, electron microscopy and confocal microscopy.<p>

Results<br> Plasma levels of PSGL‐1+ MVs were associated with increased risk of VTE. The odds ratio (OR) per one standard deviation (SD) increase in PSGL‐1+ MVs was 3.11 (95% CI: 1.41‐6.88) after adjustment for age and sex, and 2.88 (95% CI: 1.29‐6.41) after further adjustment for BMI. The PSGL‐1+ MVs originated mainly from monocytes and endothelial cells determined by double‐staining with markers of parental cells using flow cytometry and transmission electron microscopy (TEM). Scanning electron microscopy (SEM) of PSGL‐1 labeled plasma‐derived MVs displayed dominantly spherical vesicles that varied between 50 nm and 300 nm in diameter.<p>

Conclusions<br> Increased plasma levels of PSGL‐1+ MVs are associated with the risk of unprovoked VTE. Large population‐based prospective studies are required to validate our findings.