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.

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--without HDL-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 measured using anion-exchange chromatography. [3H]AA release from labelled platelets was studied by the method of Neufeld and Majerus; radioactivity was measured by liquid scintillation counting. Levels of plasma HDL-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 noted in 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 and NOx 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. nCAD 42.3 +/- 6 mumol/mg, p < 0.002).

CONCLUSIONS

CAD patients show decreased ability to produce platelet-derived NO that leads to higher platelet sensitivity to aggregating stimuli. Decreased plasma HDL-Ch may affect AA metabolism and NO production in the platelet membranes of CAD patients without LDL-hypercholesterolemia.