Dietary salt increases arterial stiffness independent of blood pressure and lifestyle factors

M. Butlin, K. Connolly, B. Spronck, D. Georgevsky, C. M. McEniery, I. B. Wilkinson, A. P. Avolio

Research output: Contribution to journalMeeting abstractpeer-review

Abstract

Background: Human studies show an association between high salt consumption and increased large artery stiffness, but are confounded by concomitant differences in blood pressure and altered lifestyle factors. Aims: To examine the effects of a high-salt diet on aortic function independent of all other factors. Methods: Sprague-Dawley rats were fed normal chow (control, 0.26% sodium chloride, n=8) or high-salt diet (HS, 8% sodium chloride, n=6) from weaning. A third group received a high-salt diet and an antihypertensive (HS+Tx, s.c. amlodipine 5 mg/kg/day, n=6). At 14–17 weeks, thoracic and abdominal aortic pressure (invasive solid-state catheters) was recorded under anesthesia over a mean arterial pressure (MAP) range of 60–150 mmHg (i.v. phenylephrine and sodium nitroprusside, 30 μg/kg/min). Aortic stiffness was assessed by pulse wave velocity (PWV) and thoracic to abdominal aortic pulse pressure amplification (PPA). Results: Conscious systolic blood pressure (tail-cuff) was greater in HS rats (control 117±13 mmHg, HS 125±12 mmHg; P=0.004) and normalized by antihypertensive treatment (HS+Tx 112±13 mmHg, P=0.12). Higher blood pressure was associated with increased kidney mass (normalized to body weight, control 0.8±0.1%, HS 1.0±0.2%; P=0.002; HS+Tx 0.9±0.1%; P=0.17) without left ventricular hypertrophy (P=0.58). Food intake was similar amongst all groups but HS and HS+Tx rats drank more with correspondingly higher urine output. HS had higher PWV (across MAP range 60–150 mmHg: control 3.6±0.1 to 4.0±0.3 m/s; HS, 4.2±0.2 to 4.6±0.3 m/s; P<0.001 at each 5 mmHg MAP interval). Increased PWV was maintained with antihypertensive treatment (HS+Tx 3.9±0.1 to 4.8±0.1 m/s; P<0.001). PPA was greater in HS (across MAP range 60 to 150 mmHg: control 0.64±0.08 to 1.24±0.11; HS 0.89±0.02 to 1.54±0.04; P<0.001 at each 5 mmHg MAP interval) and with antihypertensive therapy (HS+Tx 0.79±0.05 to 1.39±0.03; P<0.001). Conclusion: Under controlled blood pressure, a high-salt diet induced greater aortic stiffness and higher PPA, indicating salt effects on arterial stiffness are independent of blood pressure and other lifestyle factors.
Original languageEnglish
Pages (from-to)e24
Number of pages1
JournalHypertension
Volume69
Issue number6
Publication statusPublished - 2017
Event38th Annual Scientific Meeting of the High Blood Pressure Research Council of Australia - Hobart, Australia
Duration: 7 Dec 201610 Dec 2016

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