FIGURE 3.

Collagen-induced platelet aggregation. Fresh-drawn, citrated whole blood from human (n = 2), h*pvWF pigs (n = 13) and GTKO.hCD46 pigs (n = 6) was tested using a Chrono-log Whole Blood Aggregometer. (A) Collagen (2 mg/ml) was utilized as an agonist to induce platelet aggregation. Gray-shaded area represents normal range for collagen-induced platelet aggregation in humans (15–27 Ohms). (B) Blood from h*pvWF pigs was similar to human blood in its functional ability to stimulate platelet aggregation (a;ab p = .14). Platelet aggregation was lower in blood from h*pvWF versus control pvWF (a;b p < .001). Mean results were compared using one-way ANOVA and Tukey’s multiple comparison test. Spontaneous platelet aggregation: Human platelet-rich plasma (hPRP) was prepared from blood of a healthy donor. PPP was prepared from h*pvWF and GTKO.hCD46 pigs. (C) hPRP was mixed with human/porcine PPP (1:1) and platelet aggregation was monitored without adding an agonist. (D) PPP from h*pvWF pigs and human did not trigger platelet aggregation whereas PPP from GTKO.hCD46 pigs triggered platelet aggregation within 1–2 s. Representative tracing from one experiment shown using a bi-allelic h*pvWF pig (A & C), while histogram bars represent mean and SD of both mono- and bi-allelic pigs