Intraplatelet cyclic 3'-5' guanosine monophosphate is related to serum cholesterol

Nitric oxide (NO) exerts its vasodilator and antiaggregatory effects through activation of soluble guanylate cyclase and the consequent increase in the concentration of cGMP in target cells. We conducted this study in order to evaluate relationships between intraplatelet cGMP levels and risk factors for atherosclerosis in middle aged subjects. Intraplatelet cGMP was determined by radioimmunoassay and related to age, BMI, blood pressure, antihypertensive treatment, total, LDL and HDL cholesterol, triglycerides, blood glucose, HbA1c, smoking habit and intimal thickness of the common carotid artery in 265 subjects participating in a health survey (age 59 +/- 6 years, range 48-68 years, 121 females, 144 males). Intraplatelet cGMP concentration was inversely correlated with total serum cholesterol (r = -0.18; p < 0.01) and HDL cholesterol (r = -0.14, p < 0.05) as well as with platelet count (r = -0.29; p < 0.001). When platelet count was adjusted for, only the correlation between total serum cholesterol and cGMP remained significant. No significant correlations could be demonstrated between intraplatelet cGMP levels and measurable parameters of atherosclerosis. Lower levels of the vasodilating and antiaggregating mediator cGMP in platelets are related to higher levels of serum total cholesterol. These results favour the hypothesis of a relationship between lipid levels and NO associated vasodilator and antiaggregating function in atherosclerosis.