Effects of magnesium on platelet aggregation and adhesion. Magnesium modulates surface expression of glycoproteins on platelets in vitro and ex vivo.
Magnesium deficiency and its association with platelet hyperreactivity has been well recognised in a variety of diseases including myocardial infarction, preeclampsia, and diabetes. In order to investigate potential effects of intravenous Mg2+ supplementation, platelet function was studied by measurements of in vitro bleeding time (BT) and of fibrinogen (Fg)-mediated aggregation of washed platelets. In addition, the effect of Mg2+ on platelet adhesion onto immobilised Fg, on Fg binding to activated platelets, and on surface expression of GMP-140 or GP53 was evaluated. Mg2+ (4 mM) prolonged in vitro BT by 30% and inhibited Fg-mediated aggregation significantly, independent of the agonist used to initiate platelet aggregation (ADP, collagen, epinephrine, thrombin, phorbol ester). Adhesion of resting platelets to immobilised Fg was reduced by 50% in the presence of 2 mM Mg2+. Moreover, Mg2+ reduced Fg binding to ADP- or collagen-stimulated platelets as well as surface expression of GMP-140 with an IC50 of approximately 3 mM. Intravenous administration of Mg2+ to healthy volunteers inhibited both ADP-induced platelet aggregation (p < 0.05) by 40% and binding of Fg or surface expression of GMP-140 by 30% (p < 0.05). Thus, pharmacological concentrations of Mg2+ effectively inhibit platelet function in vitro and ex vivo.
Gawaz
M
M
First Medical Department, Technical University, Munich, Germany.
Ott
I
I
Reininger
A J
AJ
Neumann
F J
FJ
D001760:Bleeding Time; D005069:Evaluation Studies as Topic; D005340:Fibrinogen / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D008274:Magnesium / Q000494:pharmacology*; D010973:Platelet Adhesiveness / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*; D010980:Platelet Membrane Glycoproteins / Q000187:drug effects*; D011485:Protein Binding; D012016:Reference Values
D010975:Platelet Aggregation Inhibitors; D010980:Platelet Membrane Glycoproteins; D005340:Fibrinogen; D008274:Magnesium