Boddi M, Poggesi L, Coppo M, Zarone N, Sacchi S, Tania C, Neri Serneri G G
Istituto di Medica Generale e Cardiologia, University of Florence, Italy.
Hypertension. 1998 Mar;31(3):836-42. doi: 10.1161/01.hyp.31.3.836.
A growing body of evidence supports the existence of a tissue-based renin-angiotensin system (RAS) in the vasculature, but the functional capacity of vascular RAS was not investigated in humans. In 28 normotensive healthy control subjects, the metabolism of angiotensins through vascular tissue was investigated in normal, low, and high sodium diets by the measurement of arterial-venous gradient of endogenous angiotensin (Ang) I and Ang II in two different vascular beds (forearm and leg), combined with the study of 125I-Ang I and 125I-Ang II kinetics. In normal sodium diet subjects, forearm vascular tissue extracted 36+/-6% of 125I-Ang I and 30+/-5% of 125I-Ang II and added 14.9+/-5.1 fmol x 100 mL(-1) x min(-1) of de novo formed Ang I and 6.2+/-2.8 fmol x 100 mL(-1) x min(-1) of Ang II to antecubital venous blood. Fractional conversion of 125I-Ang I through forearm vascular tissue was about 12%. Low sodium diet increased (P<.01) plasma renin activity, whereas de novo Ang I and Ang II formation by forearm vascular tissue became undetectable. Angiotensin degradation (33+/-7% for Ang I and 30+/-7% for Ang II) was unchanged, and vascular fractional conversion of 125I-Ang I decreased from 12% to 6% (P<.01). In high sodium diet subjects, plasma renin activity decreased, and de novo Ang I and Ang II formation by forearm vascular tissue increased to 22 and 14 fmol x 100 mL(-1) x min(-1), respectively (P<.01). Angiotensin degradation did not significantly change, whereas fractional conversion of 125I-Ang I increased from 12% to 20% (P<.01). Leg vascular tissue functional activities of RAS paralleled those of forearm vascular tissue both at baseline and during different sodium intake. These results provide consistent evidence for the existence of a functional tissue-based RAS in vascular tissue of humans. The opposite changes of plasma renin activity and vascular angiotensin formation indicate that vascular RAS is independent from but related to circulating RAS.
越来越多的证据支持血管系统中存在基于组织的肾素 - 血管紧张素系统（RAS），但尚未在人体中研究血管RAS的功能能力。在28名血压正常的健康对照受试者中，通过测量两种不同血管床（前臂和腿部）内源性血管紧张素（Ang）I和Ang II的动静脉梯度，并结合对125I - Ang I和125I - Ang II动力学的研究，来探究在正常、低钠和高钠饮食情况下血管组织对血管紧张素的代谢情况。在正常钠饮食的受试者中，前臂血管组织摄取了36±6%的125I - Ang I和30±5%的125I - Ang II，并向前臂静脉血中添加了14.9±5.1 fmol×100 mL-1×min-1的新生Ang I和6.2±2.8 fmol×100 mL-1×min-1的Ang II。125I - Ang I通过前臂血管组织的分数转化率约为12%。低钠饮食增加了（P<0.01）血浆肾素活性，而前臂血管组织中新生Ang I和Ang II的生成则无法检测到。血管紧张素降解（Ang I为33±7%，Ang II为30±7%）没有变化，125I - Ang I的血管分数转化率从12%降至6%（P<0.01）。在高钠饮食的受试者中，血浆肾素活性降低，前臂血管组织中新生Ang I和Ang II的生成分别增加至22和14 fmol×100 mL-1×min-1（P<0.01）。血管紧张素降解没有显著变化，而125I - Ang I的分数转化率从12%增加至20%（P<0.01）。在基线和不同钠摄入量期间，腿部血管组织RAS的功能活动与前臂血管组织的功能活动相似。这些结果为人体血管组织中存在功能性基于组织的RAS提供了一致的证据。血浆肾素活性和血管血管紧张素生成的相反变化表明，血管RAS独立于循环RAS但与之相关。
