High Levels of Soluble P-Selectin Are Associated with the Risk of Venous Thromboembolism and the P-Selectin Thr715 Variant.

The cell adhesion molecule P-selectin, which is found in the alpha granula of platelets and in Weibel-Palade bodies of endothelial cells, has been shown to play an important role in the pathophysiology of thrombosis. However, the meaning of soluble P-selectin (sP-selectin) in venous thromboembolism (VTE) is still uncertain because clinical data are limited. The purpose of this study was to investigate whether sP-selectin is associated with the risk for VTE and to elucidate the association of sP-selectin and the P-selectin gene variation (SELP) Thr715Pro in high risk patients with recurrent VTE. We recruited cases and control individuals between January 2005 and November 2005 for an analysis of sP-selectin plasma levels and the SELP Thr715Pro. Patients with a history of objectively confirmed recurrent VTE and at least one event of an unprovoked deep venous thrombosis or pulmonary embolism were enrolled. Plasma was obtained at least 3 months after the most recent event of VTE. Age and sex-matched healthy individuals served as controls. sP-selectin levels were measured with a high sensitive ELISA. The variant for the P-selectin gene was determined by a mutagenically separated PCR followed by high resolution gel-electrophoresis. Hundred-sixteen patients (53 female / 63 male; mean age +/−SD: 56 +/−12 yrs) and 129 controls (66 female / 63 male; mean age +/−SD: 53 +/−11 yrs) were enrolled. Mean concentration (+/−SD) of sP-selectin (ng/mL) was significantly higher in patients than in controls (47.28 +/−15.00 vs. 36.77 +/−11.00, p<0.001). The unadjusted odds ratio (OR) of elevated sP-selectin (cut-off level 55.10 ng/mL representing the 95^th percentile of the controls) was 8.5 (95% confidence interval (CI): [3.7–23.3], p<0.001) and increased after adjustment for factor V Leiden, prothrombin G20210A variant, elevated factor VIII level, hyperhomocysteinemia and BMI (OR=11.1, 95% CI [4.3–33.0], p<0.001). Carriers of the SELP Pro715 were more prevalent among controls than patients (21.7% versus 14.7%), however, the difference was statistically not significant (p=0.19). The subgroup of carriers of the SELP Pro715 (n=45) had significantly lower sP-selectin levels than non-carriers (31.31+/−7.94 vs. 44.10+/−14.08, p<0.001). In conclusion, our study shows a highly significant association between elevated sP-selectin levels and VTE. Furthermore, sP-selectin levels correlate with genotype status and individuals carrying the SELP Pro715 have lower levels of sP-selectin.