BACKGROUND: Endothelial dysfunction is considered the earliest stage of atherosclerosis. Postprandial phase is associated with a transient impairment of endothelial function concomitantly with the triglyceride-rich lipoprotein increase. This phenomenon may be explained by the oxidative burden induced by triglyceride-rich lipoproteins, reducing nitric oxide bioavailability. OBJECTIVE: To investigate the effect of a diet enriched with L-arginine, the substrate for nitric oxide synthesis on endothelial function in healthy volunteers. METHODS: Endothelial function (expressed as flow-mediated vasodilation (FMV) of the brachial artery), total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides, LDL-size, Lp (a) and reduced glutathione (GSH) were evaluated in seven healthy males (mean age 23 +/- 3 years) without cardiovascular risk factors. Measurements were made at baseline and 2, 4 and 6 h after a standardized oral fat load. L-arginine (6 g daily) was administered for 10 days. On the 11th day the oral fat load and the parameters examined previously at entry were repeated. RESULTS: After the first oral fat load, FMV significantly decreased at 2 and 4 h, and overlapped with the basal levels at 6 h. After L-arginine treatment, FMV significantly decreased at 2 h and normalized after 4 and 6 h. Triglycerides increased at 2 and 4 h and decreased after 6 h in both sets of observations relating to before and after L-arginine administration. GSH dropped 2 h after the fat load, both before and after L-arginine. Before L-arginine, FMV exhibited a significant correlation with triglycerides (r= -0.426, P= 0.024) and GSH (r=0.48; P=0.009). After L-arginine, FMV was related to GSH (r=0.39; P=0.03) but not to triglycerides (r= -0.12; P=0.52). CONCLUSION: Postprandial endothelial impairment is partly abolished by L-arginine administration. These data, which require confirmation, suggest the importance of dietary choice for atherosclerosis prevention even in young healthy subjects.
Oral L-arginine administration attenuates postprandial endothelial dysfunction in young healthy males
MARCHESI, Simona;LUPATTELLI, Graziana;SIEPI, Donatella;VAUDO, Gaetano;MANNARINO, Elmo
2001
Abstract
BACKGROUND: Endothelial dysfunction is considered the earliest stage of atherosclerosis. Postprandial phase is associated with a transient impairment of endothelial function concomitantly with the triglyceride-rich lipoprotein increase. This phenomenon may be explained by the oxidative burden induced by triglyceride-rich lipoproteins, reducing nitric oxide bioavailability. OBJECTIVE: To investigate the effect of a diet enriched with L-arginine, the substrate for nitric oxide synthesis on endothelial function in healthy volunteers. METHODS: Endothelial function (expressed as flow-mediated vasodilation (FMV) of the brachial artery), total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides, LDL-size, Lp (a) and reduced glutathione (GSH) were evaluated in seven healthy males (mean age 23 +/- 3 years) without cardiovascular risk factors. Measurements were made at baseline and 2, 4 and 6 h after a standardized oral fat load. L-arginine (6 g daily) was administered for 10 days. On the 11th day the oral fat load and the parameters examined previously at entry were repeated. RESULTS: After the first oral fat load, FMV significantly decreased at 2 and 4 h, and overlapped with the basal levels at 6 h. After L-arginine treatment, FMV significantly decreased at 2 h and normalized after 4 and 6 h. Triglycerides increased at 2 and 4 h and decreased after 6 h in both sets of observations relating to before and after L-arginine administration. GSH dropped 2 h after the fat load, both before and after L-arginine. Before L-arginine, FMV exhibited a significant correlation with triglycerides (r= -0.426, P= 0.024) and GSH (r=0.48; P=0.009). After L-arginine, FMV was related to GSH (r=0.39; P=0.03) but not to triglycerides (r= -0.12; P=0.52). CONCLUSION: Postprandial endothelial impairment is partly abolished by L-arginine administration. These data, which require confirmation, suggest the importance of dietary choice for atherosclerosis prevention even in young healthy subjects.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
