Nitric oxide production and arachidonic acid metabolism in platelet membranes of coronary heart disease patients with and without diabetes.
OBJECTIVE
To evaluate the levels of nitrite (NO(-)(2)) and nitrate (NO(-)(3)) ions and the incorporation of [(3)H]arachidonic acid (AA) into phospholipids of platelet membranes from coronary artery disease (CAD) patients with and without diabetes (NIDDM).


METHODS
Eighteen CAD patients (group A), 18 CAD patients with NIDDM (group B), and 20 healthy controls (group C) without dyslipidemia, peripheral vascular disease and hypertension were included in the study. The groups were matched for age, sex and body mass index. The diagnosis of CAD was confirmed by coronary angiography. The nitric oxide end products (NOx), NO(-)(2) plus NO(-)(3) ions in platelet membranes, were determined using a spectrophotometric method based on the Griess reaction. The turnover of phospholipids was evaluated by incorporation of [(3)H]AA into platelet membrane phospholipids.


RESULTS
A significantly smaller amount of NOx ions was in the platelet membrane of groups A (40 +/- 8 micromol/l) and B (29 +/- 10 micromol/l) than C (57 +/- 6 micromol/l), p < 0.001. Conversely a significantly greater amount of [(3)H]AA was incorporated into platelet phospholipids of group B patients (5,123 +/- 1,637 dpm/mg) than groups A (3,159 +/- 1,253 dpm/mg; p < 0.002) and C (1,621 +/- 417 dpm/mg). An inverse correlation between [(3)H]AA incorporation and NOx levels was established: r = -0.76 (p < 0.05, n = 36) in CAD patients.


CONCLUSIONS
Diabetes in CAD patients decreased the ability to produce platelet-derived NO and affects AA metabolism. This may result in higher platelet sensitivity to aggregating stimuli.
Tretjakovs
Peteris
P
Centre of Endocrinology, P Stradin's Clinical University Hospital, University of Latvia, Riga, Latvia. tretjako@latnet.lv
Kalnins
Uldis
U
Dabina
Inese
I
Erglis
Andrejs
A
Dinne
Iveta
I
Jurka
Antra
A
Latkovskis
Gustavs
G
Zvaigzne
Agnis
A
Pirags
Valdis
V
D000328:Adult; D000368:Aged; D016718:Arachidonic Acid / Q000032:analysis*; D001792:Blood Platelets / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D003324:Coronary Artery Disease / Q000209:etiology* / Q000378:metabolism*; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009566:Nitrates / Q000032:analysis*; D009573:Nitrites / Q000032:analysis*; D010743:Phospholipids / Q000378:metabolism; D015539:Platelet Activation; D013053:Spectrophotometry
D009566:Nitrates; D009573:Nitrites; D010743:Phospholipids; D016718:Arachidonic Acid