Increased platelet activation in subjects chronically exposed to cadmium: A pilot study

Cadmium exposure has been reported to be associated with the risk of vascular disorders. Here, we investigated platelet activity in subjects with chronic cadmium exposure. Eighteen and 15 women participated in this study as chronically cadmium-exposed and control non-exposed subjects, respectively. Plasma P-selectin and CD40 ligand (CD40L), soluble markers of platelet activation, were measured. Platelet aggregation in whole blood, P-selectin and activated glycoprotein (aGP) IIb/IIIa expression on platelets and platelet-leukocyte aggregates were determined. The levels of plasma P-selectin and CD40L increased in subjects with chronic cadmium exposure compared with control subjects. Platelet aggregation induced by adenosine diphosphate (ADP) was higher in cadmium-exposed subjects than control subjects. Cadmium-exposed subjects had higher baseline and ADP-induced aGPIIb/IIIa expression on platelets than control subjects. Platelet-neutrophil aggregates also increased in cadmium-exposed subjects. Blood cadmium correlated with ADP-induced aggregation, aGPIIb/IIIa expression and platelet-neutrophil aggregates, while urinary cadmium correlated with soluble P-selectin. However, cadmium only at high concentration (15 mu M) could potentiate ADP-induced platelet activation in vitro. In conclusion, our pilot data show that cadmium-exposed subjects have increased baseline platelet activation and reactivity.