Comparison of P-selectin exposure between control and stroke cohorts and correlation between GPVI-dimer and P-selectin exposure.

A) Comparison of P-selectin surface exposure of the stroke patients with the controls show that the stroke patients have more activated “resting” platelets (i.e., before stimulation by exogenous agonist) and after CRP-XL (4 μg/mL) addition compared to the control group (P<0.0001). P-selectin exposure in response to ADP (0.5 μM) was not significantly different compared to controls. The error bars represent the median (Q1–Q3) %PP of each of the cohorts and P-values were calculated by the Mann-Whitney U-test for non-parametric data. B) GPVI-dimer expression and resting P-selectin exposure in both control and stroke patients are strongly correlated at admission (P <0.0001 for both). C) GPVI-dimer expression is correlated with P-selectin exposure in response to CRP-XL in the stroke patients at admission (P = 0.004). Correlations were calculated using Spearman’s rank correlation coefficient and regression line is presented for each data set. %PP = percentage of platelets positive, ns = not significant.