PLATELET-FUNCTION AND PLATELET-LEUKOCYTE ADHESION IN SYMPTOMATIC CORONARY HEART-DISEASE - EFFECTS OF INTRAVENOUS MAGNESIUM

Spontaneous P-selectin surface expression on platelets and platelet-le ukocyte adhesion was increased in patients with symptomatic coronary h eart disease (n = 12) compared to normal controls (n = 10) (p < 0.05). ADP-induced P-selectin expression and platelet-leukocyte adhesion was also enhanced in the patient group (p < 0.05). Administration of intr avenous Mg2+ significantly reduced both platelet surface expression of P-selectin and platelet-leukocyte adhesion ex vivo (p < 0.02). The ef fect of extracellular Mg2+ was evaluated in in vitro experiments. Both in whole blood acid in isolated neutrophil suspension Mg2+ inhibited platelet adhesion to neutrophils dose dependently with half maximal ef fects at 4 mM. Moreover, Mg2+ inhibited adhesion of isolated platelet membranes to neutrophils. We conclude that platelet function is altere d in symptomatic coronary heart disease and can be modulated by admini stration of intravenous Mg2+.