Vascular adhesion molecule-1 and markers of platelet function before and after a treatment with iloprost or a supervised physical exercise program in patients with peripheral arterial disease

Abstract

Platelet function and levels of vascular adhesion molecule-1 (VCAM-1) were investigated in 24 patients with peripheral arterial disease at Fontaine stage II undergoing a 2 weeks treatment with iloprost (0.5–2 ng/kg/h i.v. infused, 6 h/day) or a 2 weeks supervised physical training, randomly assigned. Patients were studied before (T0) and after (T14) treatments and 10 days later (T24). The adhesion of washed platelets to fibrinogen coated microwells was reduced after treatment both with iloprost (1.9±0.4 vs 6.8±0.7 %; T24 vs T0; M±SEM; p<0.05) and physical exercise (3.0±1.0 vs 6.7±0.7; p<0.05) while adhesion to human plasma coated microwells was reduced only after treatment with iloprost (1.9±0.8 vs 5.8±0.9; p<0.05). The expression of fibrinogen receptor (glycoprotein IIb/IIIa) on platelets, measured by flow-cytometry was also reduced after iloprost treatment (17.1±1.5 vs 31.8±4.8 AU; p<0.05) and physical exercise (14.6±1.5 vs 34.0±3.3; p<0.05). The urinary excretion of platelet thromboxane A 2 metabolite 2,3-dinor-thromboxane B 2 decreased only in patients treated with iloprost (154.7±97.9 vs 256.2±106.4 pg mg creatinine −1; p<0.05). Similarly plasma VCAM-1 was lower in patients who were treated with iloprost (827.7±77.4 vs 999.0±83.8 ng ml −1; p<0.05). In conclusion, both iloprost and physical exercise seem to act on reversible phenomena such as the expression of adhesion molecules or ex vivo adhesion, whereas only iloprost reduces thromboxane A 2 biosynthesis in vivo. This anti-platelet activity seems to be extended in time and to be associated with an improvement in vascular function.