Investigating the effect of platelet function on HT development, we found that HT did not occur in mice that demonstrated beforehand high activation rates upon in vitro stimulation with thrombin (CD62P expression >80%), whereas mice showing reduced platelet activation rates (CD62P expression <80%) were at higher risk for HT development (CD62P expression >80%: 0.9 ± 0.3 mm2; CD62P expression <80%: 10.8 ± 4.4mm2, p = 0.0335, Figure 3A). Here, SELP is linked to hematocrit.