The purpose of this study was to examine whether insulin's effect to vasodilate skeletal muscle vasculature is mediated by endothelium-derived nitric oxide (EDNO)

Sensitivity and resistance to the effects of sodium were evaluated in normotensive and hypertensive humans by two approaches. Blood pressure was measured after an intravenous infusion of 2 L of normal (0.9%) saline and after sodium and volume depletion induced by a low sodium diet and furosemide administration in 378 normal volunteers and 198 subjects with essential hypertension. Those in whom mean arterial blood pressure decreased by at least 10 mm Hg after sodium and volume depletion were considered sodium-sensitive, and those with a decrease of 5 mm Hg or less (including an increase in pressure) were considered sodium-resistant. The second study utilized the blood pressure response to modest dietary sodium restriction in 74 normotensive subjects to identify sodium sensitivity and resistance. In both studies the responses were heterogeneous. In the first study significantly more hypertensive subjects were sodium-sensitive, as compared with those in the normotensive group (p less than 0.001). Plasma renin activity (low, normal, or high) did not predict sodium responses. In both groups sodium-sensitive individuals were significantly older (p less than 0.001) and had lower baseline renin values than sodium-resistant subjects. Factors related to the change in mean arterial blood pressure after sodium and volume depletion included baseline pressure (r = -0.54, p less than 0.001) and age (r = -0.16, p = 0.002 in the normotensive group; r = -0.28, p less than 0.001 in the hypertensive group). The response to dietary sodium restriction was also correlated with baseline pressure (r = 0.61, p less than 0.001) and the initial urinary sodium excretion (r = 0.27, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Abstract-Although factors such as age, blood pressure, and its responsiveness to changes in sodium balance and extracellular fluid volume status (salt sensitivity) are associated with an increased risk of end-organ disease and cardiovascular events in hypertensive subjects, no such relationship with mortality has been demonstrated for salt sensitivity in normotensive subjects. We conducted long-term follow-up of 430 normal and 278 hypertensive subjects in whom assessment of salt sensitivity of blood pressure was performed as long as 27 years ago. We ascertained the status of 596 subjects (85% of the total population), 123 (21%) of whom had died. The following initial measurements were significantly (PϽ0.002) associated with subjects who had died compared with subjects known to be alive: age at study, pulse pressure, systolic, diastolic, and mean arterial pressures, hypertension, salt sensitivity, baseline renin levels, and body mass index (but not body weight). A stepwise logistic regression found the following independent predictors of death (odds ratio, 95% CI): age at initial study (1.08, 1.06 to 1.10), baseline blood pressure (1.03, 1.01 to 1.04), sodium sensitivity (1.73, 1.02 to 2.94), and male gender (1.91, 1.15 to 3.17). When survival curves were examined, normotensive salt-sensitive subjects aged Ͼ25 years when initially studied were found to have a cumulative mortality similar to that of hypertensive subjects, whereas salt-resistant normotensive subjects had increased survival (PϽ0.001).These observations provide unique evidence of a relationship between salt sensitivity and mortality that is independent of elevated blood pressure.

In patients with ESRD undergoing renal transplantation, vascular calcification of the medial layer of the inferior epigastric artery is common (44%), can be detected by spiral CT, and is associated with deposition of bone matrix proteins. This implies an active cell-mediated process, raising hope that directed intervention can arrest this process.