Impairment of Endothelial Function in Salt-Sensitive Hypertension in Humans

Abstract

In this study, we evaluated the relationship between the endothelium-dependent vasodilation and salt sensitivity in patients with essential hypertension. Fifteen untreated hypertensive male patients (age, 29 to 54 years) were sodium restricted (5 g/day) for 1 week, and placed on a high salt diet (20 g/day) the second week. At the end of each period, measurements of forearm vascular responses to drugs (acetylcholine, 3 to 24 microg/min; sodium nitroprusside, 0.15 to 1.2 microg/min; norepinephrine, 0.15 to 1.2 microg/min; and N(G)-monomethyl-L-arginine [L-NMMA], 1 to 8 micromol/min) were obtained by using strain-gauge venous plethysmography. Subjects were divided into two groups according to the blood pressure response to sodium loading: salt-sensitive hypertensive group (24-h mean increase of arterial pressure > or = 10%; n = 6) and salt-resistant group (< 10%; n = 9). The two groups showed no significant difference in clinical data or mean arterial pressure during low salt intake. The dose-dependent vasodilation induced by acetylcholine was significantly reduced (P < .05) in the salt-sensitive hypertensive patients v the salt-resistant patients regardless of sodium loading. There were no differences between the two groups in response to sodium nitroprusside, norepinephrine, or L-NMMA. These results indicate that vasodilation to acetylcholine is reduced in salt-sensitive hypertensive patients even on restricted sodium diets. This may contribute to blood pressure elevation when sodium intake is increased.

Surgical Menopause Increases Salt Sensitivity of Blood Pressure

“…SS hypertensive patients have a higher incidence of left ventricular hypertrophy, 19,20 endothelial dysfunction, 21 hyperlipidemia, 22,23 and microalbuminuria [22][23][24] compared with salt-resistant hypertensive patients. In addition, an association between insulin resistance and SS in nondiabetic, nonobese, essential hypertensive subjects has been reported.…”

Endothelial dysfunction in normotensive salt-sensitive subjects

“…23 Previous work has demonstrated that the impairment of endotheliumdependent vasodilation as assessed by strain-gauge plethysmography, is independent of NaCl intake in SS patients but not in SR patients, and that forearm vascular responses are not affected by changes in NaCl intake in SS patients or SR patients. 16,24 However, Higashi et al 25 observed no differences in vascular responses between SS patients and SR patients during a regular or high-salt diet. Furthermore, Dickinson et al 15 reported that a 2-week lowsalt diet improved endothelium-dependent vasodilation in normotensive subjects independently of the changes in measured resting BP.…”

“…5,6 Studies in patients with essential hypertension have suggested that high salt intake and/or salt sensitivity is associated with impaired endothelial function. [7][8][9] Measurement of flow mediated dilation (FMD) in the brachial artery using ultrasound is noninvasive and is an accurate indicator of NO production. [10][11][12][13] Furthermore, FMD measurement is an accepted index of conduit artery endothelial function, which can serve as an independent predictor of cardiovascular events.…”

Postovariectomy Hypertension Is Linked to Increased Renal AT 1 Receptor and Salt Sensitivity

“…[27][28][29][30] After menopause, the loss of the ovarian hormones may unmask a population of women prone to salt-sensitive hypertension that would be at higher risk for cardiovascular morbidity and mortality. Clinically, we infer that after menopause, estrogen deficiency promotes an overexpression of renal AT 1 receptors resulting in oxidative stress, 41 disturbed renal sodium handling, 42 and hypertension, particularly in women genetically prone to salt sensitivity.…”