AIM: To evaluate nitric oxide (NO) production and [3H]arachidonic acid(AA) incorporation into platelet membranes of coronary artery disease (CAD) patients with/without HDL-hypocholesterolemia.MATERIAL: 16 healthy controls (C), 14 CAD patients with plasma HDL-hypocholesterolemia (nCAD) and 14--withoutHDL-hypocholesterolemia (nCAD). All subjects were without peripheral vascular disease and hypertension.The groups were matched for age, sex, BMI. The diagnosis of CAD was substantiated by coronary angiography.METHODS: Nitric oxide end products xNO (NO2- plus NO3-) levels in the platelet membranes were measuredusing anion-exchange chromatography. [3H]AA release from labelled platelets was studied by the methodof Neufeld and Majerus; radioactivity was measured by liquid scintillation counting. Levels of plasmaHDL-cholesterol (HDL-Ch) and triglycerides were enzymatically determined. RESULTS: Significant increase(mean +/- SD; Mann-Whitney U test) of [3H]AA incorporation into platelet membrane phospholipids was notedin CAD patients in comparison with healthy subjects (p < 0.001). A correlation (multiple regression analysis)was established between HDL-C level and [3H]AA (r = -0.58, p < 0.05, n = 28); and between HDL-Ch andNOx levels (r = 0.76, p < 0.05, n = 28) in CAD patients. CAD patients had lower NOx than healthy subjects(p < 0.0001), NOx was lower in the group with decreased HDL-Ch concentration (wCAD 36 +/- 5 vs. nCAD42.3 +/- 6 mumol/mg, p < 0.002). CONCLUSIONS: CAD patients show decreased ability to produce platelet-derivedNO that leads to higher platelet sensitivity to aggregating stimuli. Decreased plasma HDL-Ch may affectAA metabolism and NO production in the platelet membranes of CAD patients without LDL-hypercholesterolemia.

Keywords: Arachidonic Acid, Blood Platelets, Cell Membrane, Comparative Study, Coronary Disease, Hypercholesterolemia, Lipoproteins, HDL Cholesterol, Lipoproteins, LDL Cholesterol, Membrane Lipids, Nitric Oxide, Nitrogen Oxides, Phospholipids, Reference Values, Regression Analysis, Tritium