Strongly enhanced platelet adhesion under flow conditions <i>ex vivo</i> and on the injured carotid artery upon A<i>ß</i> stimulation of platelets <i>in vivo</i>.

<p>(A) Representative phase contrast images show platelet adhesion on collagen under flow conditions at a shear rate of 1000 sec⁻¹ (upper panel) and 1700 sec⁻¹ (lower panel) are shown. Scale bar indicates 20 µm. Bar graphs depict mean values ±SEM of the number of adherent cells per visual field [212×229 µm]. The platelet agonist ADP served as positive control, (n = 5 per group), **p<0.01 and ***p<0.001. (B) Platelets adhere to immobilized A<i>ß</i> under static and flow conditions (shear rate 1700 sec⁻¹). Coverslips coated with 250 µg/ml collagen and 1 mg/ml fibrinogen served as positive control. Representative phase contrast images are shown. (C) Representative images show platelet thrombus formation on collagen and on collagen/A<i>ß</i>, respectively, at a shear rate of 1000 sec⁻¹. Scale bar indicates 20 µm. Bar graphs depict mean values ±SEM of surface coverage, n = 5 per group, *p<0.05 and ***p<0.001. (D) Platelet adhesion at the injured carotid artery 10 min after injury. DCF-labeled platelets of C57BL/6J mice were incubated with vehicle or 50 µg/ml A<i>ß</i> for 30 min and injected into a C57BL/6J recipient mouse. Scale bar 50 µm. (E) Bar graphs depict mean values ±SEM showing the number of firmly adherent platelets at the vessel wall per mm² after 5, 10 and 30 min after injury of seven independent experiments. *p<0.05, **p<0.01.