Plasma HDL-cholesterol has an effect on nitric oxide production and arachidonic acid metabolism in the platelet membranes of coronary heart disease patients without LDL-hypercholesterolemia
Peteris Tretjakovs, Uldis Kalnins, Inese Dabina, Iveta Dinne, Andrejs Erglis, Indulis Kumsars, Antra Jurka
Med Sci Monit 2000; 6(3): CR507-511
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, Female, Humans, Hypercholesterolemia, Lipoproteins, HDL Cholesterol, Lipoproteins, LDL Cholesterol, Male, Membrane Lipids, Middle Aged, Nitric Oxide, Nitrogen Oxides, Phospholipids, Reference Values, Regression Analysis, Tritium