A normal diet reduced serotonin hyperresponsiveness in 4 of 8 monkeys at 4 months and 6 of 8 monkeys at 8 months, preceding detectable changes in atherosclerotic lesion mass.
Does a normal diet improve functional vasoconstrictor responses to serotonin before structural regression in monkeys with diet-induced atherosclerosis?
Functional improvement of the arterial wall, characterized by reduced hyperresponsiveness to serotonin, occurs early during dietary regression of atherosclerosis and precedes detectable changes in atherosclerotic lesion mass.
BACKGROUND: Vasoconstrictor responses to serotonin are augmented in monkeys with diet-induced atherosclerosis and improve after 18 months of normal diet. We tested the hypothesis that functional improvement may occur early during regression, before evidence of structural improvement. METHODS AND RESULTS: Responses of the iliac artery to serotonin were measured by quantitative angiography and a Doppler flow probe in several groups of monkeys: (1) normal monkeys, (2) monkeys fed an atherogenic diet for 2 years (atherosclerotic), and (3) monkeys fed an atherogenic diet for 2 years (preregression) followed by a normal diet for 4, 8, or 12 months (regression). In normal monkeys, serotonin produced minimal constriction of the iliac artery, and blood flow to the legs increased. In atherosclerotic monkeys, there was pronounced constriction of the iliac artery, and blood flow to the legs decreased markedly. After 4 months of regression diet, four of eight monkeys demonstrated marked reduction in hyperresponsiveness to serotonin angiographically, and by 8 months, six of eight monkeys had significant improvement. After regression, serotonin produced minimal changes in flow. There was no reduction in intimal area (ie, atherosclerotic lesion) in iliac arteries from regression monkeys compared with atherosclerotic monkeys, but there was a marked reduction in cholesteryl ester in arteries from regression monkeys. CONCLUSIONS: Abnormal vasoconstrictor responses to serotonin usually return to or toward normal within a few months during regression of atherosclerosis. Functional improvement occurs in conjunction with early resorption of lipid from the arterial wall and occurs before detectable changes in mass of the atherosclerotic lesion.
Benzuly et al. (Fri,) conducted a other in diet-induced atherosclerosis. Normal diet vs. Atherogenic diet was evaluated on Responses of the iliac artery to serotonin measured by quantitative angiography and a Doppler flow probe. A normal diet reduced serotonin hyperresponsiveness in 4 of 8 monkeys at 4 months and 6 of 8 monkeys at 8 months, preceding detectable changes in atherosclerotic lesion mass.