AIM. The main purpose of this work was to study the antiplatelet effect of the vitamin B6 vitamers pyridoxine (PN), pyridoxamine (PM), pyridoxal (PL) and pyridoxal phosphate (PLP) in patients with coronary artery disease.
METHODS. Patients suffering from coronary artery disease were included in the study. Venous blood was collected in tubs with 3.8% trisodium citrate solution. Plateletrich plasma (PRP) was obtained after the centrifugation of citrated blood at 160 x g for 10 min at room temperature. Platelets were counted in a Swelab cell counter and adjusted to a final concentration of 250 x 109 cells/l. The IC50 values for the vitamers of vitamin B6 were measured simultaneously by the optical method in a Chronolog aggregometer and by the impedance method in a Swelab cell counter.
RESULTS. The IC50 values obtained by the optical method were (mM) 1.5 ± 0.2, 1.3 ± 0.3,
1.6 ± 0.4 and 0.14 ± 0.04 for PN, PL, PM and PLP. The respective values obtained by the impedance method were (mM) 1.7 ± 0.3, 1.3 ± 0.3, 1.9 ± 0.3 and 0.22 ± 0.07. The respective values obtained by either method did not differ significantly. Since different
vitamers of vitamin B6 are simultaneously present in blood plasma, the effect of their combination was studied. The same vitamers used in a combination were essentially more effective for inhibiting platelet aggregation.
CONCLUSION. Vitamin B6 vitamers each alone inhibit platelet aggregation at millimolar concentrations. The same vitamers in combination are effective at micromolar concentrations. This may suggest that vitamin B6 vitamers in combinations may play some role in atherothrombosis.