Department of Nutrition, Food and Exercise Sciences, College of Human Sciences, Florida State University, Tallahassee, Florida, USA.
Am J Hypertens. 2010 Jan;23(1):12-6. doi: 10.1038/ajh.2009.195. Epub 2009 Oct 22.
Oral L-citrulline is efficiently converted to L-arginine, which has been shown to decrease brachial blood pressure (BP) at rest and during the cold pressor test (CPT). However, aortic BP may better reflect cardiovascular risk than brachial BP. The purpose of this study was to test the hypothesis that oral L-citrulline supplementation attenuates brachial BP and aortic hemodynamic responses to CPT.
Brachial BP, aortic BP, stroke volume (SV), and wave reflection at rest and during CPT were evaluated in 17 young (21.6 +/- 0.9 years) normotensive men. Subjects were randomly assigned to 4 weeks of oral L-citrulline (6 g/day) or placebo in a crossover design. Hemodynamic responses to CPT were reevaluated after each treatment.
During CPT, there were significant (P < 0.05) increases in brachial and aortic BP [systolic (SBP), diastolic (DBP), and pulse pressure (PP)], augmentation index (AIx), SV, and a decrease in transit time of the reflected wave (Tr) from baseline. Compared to placebo, oral L-citrulline treatment decreased (P < 0.05) brachial SBP (-6 +/- 11 mm Hg), aortic SBP (-4 +/- 10 mm Hg), and aortic PP (-3 +/- 6 mm Hg) during CPT but not at rest. There was an inverse correlation (r = -0.40, P < 0.05) between changes in aortic SBP and Tr during CPT after L-citrulline supplementation.
We conclude that oral L-citrulline supplementation attenuates the brachial SBP, aortic SBP, and aortic PP responses to CPT in young normotensive men. Increased wave reflection time contributes to the reduction in aortic SBP response to CPT.
口服 L-瓜氨酸可有效地转化为 L-精氨酸，已被证明可降低静息时和冷加压试验（CPT）期间的肱动脉血压（BP）。然而，主动脉 BP 可能比肱动脉 BP 更好地反映心血管风险。本研究旨在检验口服 L-瓜氨酸补充是否能减弱 CPT 对肱动脉 BP 和主动脉血流动力学反应的假说。
在 17 名年轻（21.6 +/- 0.9 岁）血压正常的男性中评估静息时和 CPT 期间的肱动脉 BP、主动脉 BP、每搏量（SV）和反射波。受试者随机接受 4 周的口服 L-瓜氨酸（6 g/天）或安慰剂交叉设计。在每种治疗后重新评估 CPT 对血流动力学的反应。
在 CPT 期间，肱动脉和主动脉 BP [收缩压（SBP）、舒张压（DBP）和脉压（PP）]、增强指数（AIx）、SV 和反射波的传递时间（Tr）均有显著增加（P < 0.05）。与安慰剂相比，口服 L-瓜氨酸治疗可降低 CPT 期间的肱动脉 SBP（-6 +/- 11 mm Hg）、主动脉 SBP（-4 +/- 10 mm Hg）和主动脉 PP（-3 +/- 6 mm Hg），但在静息时则无变化。在 L-瓜氨酸补充后，CPT 期间主动脉 SBP 和 Tr 的变化呈负相关（r = -0.40，P < 0.05）。
我们得出结论，口服 L-瓜氨酸补充可减弱年轻血压正常男性的 CPT 肱动脉 SBP、主动脉 SBP 和主动脉 PP 反应。反射波时间的增加有助于降低 CPT 时主动脉 SBP 的反应。
