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J.P. Van Geffen et al.
5.22 x 10-5). Furthermore, positive correlations were also present across multiple microspots. For instance, parame- ters P2-5 (indicative of thrombus morphology and platelet aggregation) correlated between M1 (collagen I) or M2 (collagen III) with M4 [GFOGER-(GPO)n + VWF-BP] and M5 (rhodocytin + VWF-BP), i.e. all GPVI- and CLEC-2- activating surfaces (P2-5; median P values 4.39 x 10-22). Furthermore, several parameters (P2-8) correlated between M2 (collagen III) and M3 (laminin + VWF, P=0.44-1.04 x 10-11). Typically, parameters for microspot
AB
M6 (fibrinogen + VWF-BP) showed no more than poor correlation with those of other surfaces.
Multiparameter correlation and regression analysis were also performed to compare subjects’ age and sex, hemato- logic data, platelet glycoprotein expression levels and ago- nist-induced platelet activation markers by flow cytome- try. The interaction matrices displayed in Figure 3C,D show the expected correlation of sex (much stronger than age) with red blood cell and platelet counts (P<0.014), but not with other traits. Subjects’ age correlated weakly with
Figure 2. Inter-subject differences in platelet thrombus formation and other platelet traits. (A) Using blood samples from 94 genotyped healthy subjects (cohort 2), parameters of thrombus formation were assessed on microspots M1- 6. Duplicate samples were analyzed for ten of these subjects. The ratios of inter- versus intra-individual coefficients of variance per parameter and microspot are shown. (B) Heatmap of normalized parameters per microspot and per subject (rows). Scaling of 0-10 was performed per parameter across all surfaces. (C) Heatmap of additional platelet traits of the cohort of 94 subjects (scaling 0-10). Hematologic variables: white blood cell count (WBC), red blood cell count (RBC), hematocrit (HCT), platelet count (PLT), platelet crit (PCT = count x size), mean platelet volume (MPV); platelet glycoprotein expression (integrin αIIbb3: CD41a, CD41b, CD61; GPIb-V-IX: CD42a, CD42b; integrin α2b1: CD29, CD49b; CD36; GPVI; CD148). In addition, activation markers of unstimulated, ADP-, CRP-XL- or TRAP-stimulated platelets (A1-4), regarding integrin αIIbb3 activation (Int) and secretion (P-selectin expression, Sec). For details of coding of microspots (M), parameters (P) and activation markers (A), see Table 1. Raw data are provided in Online Supplementary Data File 1A-C.
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