Changes in nitric oxide production and arachidonic acid metabolism in platelet membrane in coronary heart disease patients after coronary angioplasty

Aim: to evaluate levels of nitrite (NO₂^-) and nitrate (NO₃^-) ions, and the incorporation of [³H]arachidonic acid (AA) into phospholipids in the platelet membranes of coronary heart disease (CHD) patients without dyslipidaemia. Subjects: 16 CHD patients before (bP) and 28 days after (aP) coronary angioplasty, and 18 healthy controls (C) were examined. All subjects were without peripheral vascular disease and hypertension. The groups were matched for age, sex, body mass index. Methods: NO₂^- and NO₃^- levels in the platelet membranes were measured using high-performance liquid chromatography. [³H]AA release from labelled platelets was studied by the method of Neufeld E.J., Majerus P.W.; the radioactivity was measured by liquid scintillation counting. Results: a significant increase (mean±SD; Mann-Whitney U test) of [³H]AA incorporation into platelet phospholipids was noted in CHD patients before the angioplasty in comparison with healthy subjects (p<0.0001). The ability to incorporate [³H]AA after the angioplasty was decreased (bP 4113±1357 vs. aP 2676±1485 dpm/mg, p<0.05). Analysis of nitric oxide end products NOx (NO₂^- plus NO₃^-) revealed that CHD patients had lower NO₂^- and NO₃^- levels than healthy subjects (bP 40±7 vs. C 56±5 μmol/mg, p<0.001); after the angioplasty the level of xNO increased (p<0.05). Conclusions: CHD patients show both decreased ability to produce platelet-derived NO and affected AA metabolism that lead to higher platelet sensitivity to aggregating stimuli. Results improve after coronary angioplasty.