Sierra M, Gonzalez A, Gomez-Alamillo C, Monreal I, Huarte E, Gil A, Sanchez-Casajus A, Díez J
Division of Nephrology, San Millán Hospital, Logroño, Spain.
Kidney Int Suppl. 1998 Dec;68:S10-3. doi: 10.1038/sj.ki.4490557.
Most hypertensive patients exhibit increased renal vascular resistance (RVR). This study was designed to investigate whether there exists any relationship between RVR and the production of nitric oxide (NO) in patients with essential hypertension. The study was performed in 49 non-treated patients with mild-to-moderate essential hypertension, and 20 age- and sex-matched normotensive subjects on a controlled sodium diet. Renal hemodynamics was measured in terms of the clearance of para-aminohippuric acid and inulin. Urinary excretion of nitrate and nitrite (NO3- plus NO2-) was determined as an index of NO production. As compared with normotensives, hypertensive patients exhibited higher (P < 0.001) RVR and lower (P < 0.05) urinary excretion of NO3- plus NO2-. With the 100% confidence (upper) limit of the normotensive population as a cut-off point, a subgroup of 30 hypertensives had an abnormally high RVR. The excretion of NO3- plus NO2- was lower (P < 0.005) in hypertensives with high RVR than in normotensives and the remaining hypertensives. No differences were found in the urinary excretion of NO3- plus NO2- between normotensives and hypertensives with normal RVR. Statistically significant associations were seen between diastolic blood pressure and RVR (r = 0.341, P < 0.05) and urinary excretion of NO3- plus NO2- (r = -0.387, P < 0.01) in all hypertensives. These results indicate that there is a subgroup (61%) of hypertensive patients with diminished urine levels of NO3- plus NO2- in which RVR is abnormally increased. Thus, it is suggested that in essential hypertension a diminished renal ability to produce NO by the endothelium may be involved in exaggerated renal vasoconstriction.
大多数高血压患者表现出肾血管阻力（RVR）增加。本研究旨在调查原发性高血压患者的RVR与一氧化氮（NO）生成之间是否存在任何关联。该研究对49例未经治疗的轻度至中度原发性高血压患者以及20例年龄和性别匹配、饮食中钠摄入受控的血压正常受试者进行。通过对氨基马尿酸和菊粉清除率来测量肾血流动力学。测定尿中硝酸盐和亚硝酸盐（NO3-加NO2-）的排泄量作为NO生成的指标。与血压正常者相比，高血压患者的RVR更高（P<0.001），而尿中NO3-加NO2-的排泄量更低（P<0.05）。以血压正常人群的100%置信（上限）值为切点，30例高血压患者组成的亚组RVR异常高。RVR高的高血压患者中NO3-加NO2-的排泄量低于血压正常者和其余高血压患者（P<0.005）。血压正常者与RVR正常的高血压患者之间，尿中NO3-加NO2-的排泄量无差异。在所有高血压患者中，舒张压与RVR（r=0.341，P<0.05）以及尿中NO3-加NO2-的排泄量（r=-0.387，P<0.01）之间存在统计学显著关联。这些结果表明，有一个亚组（61%）的高血压患者尿中NO3-加NO2-水平降低，其中RVR异常升高。因此，提示在原发性高血压中，内皮细胞产生NO的肾能力降低可能与肾血管过度收缩有关。
