Effects of moderate salt restriction on intralymphocytic sodium and pressor response to stress in borderline hypertension.

Ambrosioni, Ettore; Costa, Francesco; Borghi, Claudio; Montebugnoli, Lucio; Giordani, M.; Magnani, B

doi:10.1161/01.hyp.4.6.789

Cited by 60 publications

(13 citation statements)

References 36 publications

(12 reference statements)

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“…19 Esler et al 38 showed recently that untreated hypertensive patients on a free diet responded to mental arithmetic testing with increases of both total (70%) and cardiac (200%) NE spillover rates, whereas mean arterial pressure and heart rate elevations corresponded closely to the present ones. The explanation for the difference in NE spillover rates in the two studies from the same laboratory is unclear.…”

Section: Discussionmentioning

confidence: 52%

“…Furthermore, it has been suggested that pressor responses to mental arithmetic are reduced in hypertensive patients as a consequence of a low sodium diet. 19 Blood pressure and heart rate responses as well as cardiac NE spillover measurements were therefore analyzed during rest and arithmetic tests to validate whether normotensive healthy subjects fed a low sodium diet were less responsive with regard to sympathetic activation.…”

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confidence: 99%

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Evidence for increased renal norepinephrine overflow during sodium restriction in humans.

et al. 1990

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To investigate the differentiated pattern of efferent sympathetic nerve activity by means of analyzing norepinephrine kinetics in response to sodium restriction, cardiorenal sympathetic activity during rest and mental stress was studied in 12 subjects (33.3 +/- 2.6 years old, SEM) exposed to a low and a normal sodium diet; 5-40 mmol and 160-200 mmol/24 hours, respectively (crossover design). Organ norepinephrine release was calculated from organ plasma flow, arteriovenous plasma concentration gradient across the organ and the organ's fractional extraction of radiolabeled norepinephrine. Body weight and urinary sodium/24 hr fell significantly and urinary potassium/24 hr and both supine and standing blood pressure remained unchanged. Total norepinephrine release to plasma and norepinephrine plasma clearance were similar in both phases (approximately 460 ng/min and 1.90 l/min, respectively). A 138% increase in renal norepinephrine overflow was observed during sodium restriction (from 112 to 267 ng/min, p less than 0.025), which was due to elevated renal vein norepinephrine (434 versus 290 pg/ml, p less than 0.01) because renal plasma flow and renal norepinephrine extraction were unaltered. Similarly, sodium restriction caused a 168% elevation of renal renin secretion (p less than 0.05). Resting cardiac norepinephrine spillover and cardiac norepinephrine reuptake were unchanged between the two salt phases. Total and cardiac norepinephrine release, supine blood pressure, and heart rate increased to about the same extent in response to mental testing regardless of salt phase. In conclusion, sodium restriction induced a differential and physiological increase in resting renal sympathetic nervous activity, leaving cardiac norepinephrine overflow unchanged. Cardiac norepinephrine uptake was normal, which further supports the concept of a true increase of efferent renal nerve activity.

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Section: Discussionmentioning

confidence: 52%

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confidence: 99%

Evidence for increased renal norepinephrine overflow during sodium restriction in humans.

et al. 1990

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“…It may well be that efflux, as measured by Morgan, et al, and SLC respond in different ways to changes in Na balance. Working with lymphocytes, Ambrosioni et al 13 found a significant decrease in Na concentration when a diet containing 6 to 10 g NaCl/day was switched to a diet supplying 3 to 5 g. The five participants were borderline hypertensives aged 14 to 31 years; the experimental period lasted 6 weeks. No change in BP was observed.…”

Section: Discussionmentioning

confidence: 99%

Effect of dietary sodium reduction on red blood cell sodium concentration and sodium-lithium countertransport.

Cooper¹,

Trevisan²,

Horn

et al. 1984

Hypertension

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SUMMARY A randomized, crossover trial was carried out on the effect of moderate sodium reduction on red-blood-cell sodium metabolism. The participants were healthy high school students (mean age = 16 years, n = 33). Changes in sodium-lithium countertransport and intracellular sodium concentration were evaluated 24 days after a decrease in dietary sodium from approximately 110 to 40 mEq per day. Dietary sodium restriction had no significant effect on either sodium-lithium countertransport or intracellular sodium concentration. (Hypertension 6: 731-735, 1984) KEY WORDS • sodium • blood pressure • countertransport • randomized trial O VER the last several years, cation transport has become an important research focus in the'field of hypertension. '" 3 The principal areas that have been investigated relate to the relationship between cation transport and blood pressure (BP), and the influence of heredity. In addition, sex differences in some pathways for cation transport have been demonstrated, and several other factors have been linked to altered rates of exchange, including obesity, excess alcohol intake, and pregnancy. 4 " 6 If abnormal cation transport is in fact a marker and precursor of hypertension, it would be important to identify potentially modifiable environmental or lifestyle variables that might possibly be useful for pre- ventive purposes. The study reported here was a randomized single-blind crossover trial on the effect of moderate sodium restriction on red-blood-cell (RBC) sodium concentration and sodium-stimulated lithium efflux. Methods SubjectsThis experiment was performed as a part of a larger trial on sodium reduction in adolescents, which has been previously described.7 " 9 Briefly, 37 high school students attending a boarding school were recruited out of a group of 124 who volunteered for the larger study. The school was operated by the Seventh-Day Adventist Church and served lacto-ovo-vegetarian food. The school schedule required students to remain on the rural campus for 24-day periods, with a 5-day interval between each period. Informed consent was obtained from the students and their parents or guardians. Volunteers were then randomly assigned to either the regular institutional food (Group 1) or a diet estimated to be 50% reduced in sodium (Group 2). Of the 37 participants who had blood drawn at baseline, one did not complete the experimental diet and another left school. In addition, two individuals (one from each group) were found to have extremely high values of sodiumlithium countertransport (SLC), over two and one-half times the sample mean. Such extreme values usually occur in only 1% to 2% of the population.

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“…RCT withdrawn, by outcome: n=0 RCT excluded, with reasons: -duration <2 weeks: n=54 -co-intervention(s): n=25 -duplicate publication: n=11 -conducted in patients or pregnant women: n=7 -non-placebo control group: n=5 -lack of (appropriate) BP data: n=3 Data on body weight (initial level and change) of the trial population could not be retrieved for 11 sodium trials (28%) 21,22,24,28,30,35,40,41,46,57,58 and 7 potassium trials (26%) 35,40,61,66,67,73,76 Data on body mass index were missing for 80% of the trials and could therefore not be taken into account in the analysis.…”

Section: Data Extractionmentioning

confidence: 99%

Blood pressure response to changes in sodium and potassium intake: a metaregression analysis of randomised trials

2003

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The objective of the study was to assess the blood pressure response to changes in sodium and potassium intake and examine effect modification by age, gender, blood pressure, body weight and habitual sodium and potassium intake. Randomised trials of sodium reduction or potassium supplementation and blood pressure were identified through reference lists of systematic reviews and an additional MEDLINE search (January 1995-March 2001. A total of 40 sodium trials and 27 potassium trials in adults with a minimum duration of 2 weeks were selected for analysis. Data on changes in electrolyte intake and blood pressure during intervention were collected, as well as data on mean age, gender, body weight, initial electrolyte intake and initial blood pressure of the trial populations. Blood pressure effects of changes in electrolyte intake were assessed by weighted metaregression analysis, overall and in strata of trial population characteristics. Analyses were repeated with adjustment for potential confounders.Sodium reduction (median: À77 mmol/24 h) was associated with a change of À2.54 mmHg (95% CI: À3.16, À1.92) in systolic blood pressure and À1.96 mmHg (À2.41, À1.51) in diastolic blood pressure. Corresponding values for increased potassium intake (median: 44 mmol/24 h) were À2.42 mmHg (À3.75, À1.08) and À1.57 mmHg (-2.65, -0.50). Blood pressure response was larger in hypertensives than normotensives, both for sodium (systolic: À5.24 vs À1.26 mmHg, Po0.001; diastolic: À3.69 vs À1.14 mmHg, Po0.001) and potassium (systolic: À3.51 vs À0.97 mmHg, P ¼ 0.089; diastolic: À2.51 vs À0.34 mmHg, P ¼ 0.074). In conclusion, reduced intake of sodium and increased intake of potassium could make an important contribution to the prevention of hypertension, especially in populations with elevated blood pressure.

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Effects of moderate salt restriction on intralymphocytic sodium and pressor response to stress in borderline hypertension.

Cited by 60 publications

References 36 publications

Evidence for increased renal norepinephrine overflow during sodium restriction in humans.

Evidence for increased renal norepinephrine overflow during sodium restriction in humans.

Effect of dietary sodium reduction on red blood cell sodium concentration and sodium-lithium countertransport.

Blood pressure response to changes in sodium and potassium intake: a metaregression analysis of randomised trials

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