High‐salt intake up‐regulation of AT1 and AT2 protein expression in the left ventricle is independent of blood pressure

In low sodium-induced intrauterine growth restricted (IUGR) rat, foetal adrenal steroidogenesis as well as the adult renin–angiotensin–aldosterone system (RAAS) is altered. The aim of the present study was to determine the expression of cytochrome P450 aldosterone synthase (P450aldo) and of angiotensin II receptor subtypes 1 (AT1R) and 2 (AT2R) in adult adrenal glands and whether this expression could be influenced by IUGR and by high-salt intake in a sex-specific manner. After 6 weeks of 0.9% NaCl supplementation, plasma renin activity, P450aldo expression and serum aldosterone levels were decreased in all groups. In males, IUGR induced an increase in AT1R, AT2R, and P450aldo levels, without changes in morphological appearance of the zona glomerulosa (ZG). By contrast, in females, IUGR had no effect on the expression of AT1R, but increased AT2R mRNA while decreasing protein expression of AT2R and P450aldo. In males, salt intake in IUGR rats reduced both AT1R mRNA and protein, while for AT2R, mRNA levels decreased whereas protein expression increased. In females, salt intake reduced ZG size in IUGR but had no affect on AT1R or AT2R expression in either group. These results indicate that, in response to IUGR and subsequently to salt intake, P450aldo, AT1R, and AT2R levels are differentially expressed in males and females. However, despite these adrenal changes, adult IUGR rats display adequate physiological and adrenal responses to high-salt intake, via RAAS inhibition, thus suggesting that extra-adrenal factors likely compensate for ZG alterations induced by IUGR.

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High salt intake: detrimental not only for blood pressure, but also for bone health?

Endocrine ◽

10.1007/s12020-015-0626-6 ◽

2015 ◽

Vol 49 (3) ◽

pp. 580-582 ◽

Cited By ~ 2

Author(s):

Thomas Remer

Keyword(s):

Blood Pressure ◽

Bone Health ◽

Salt Intake ◽

High Salt ◽

High Salt Intake

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Abstract 142: A Fructose-but Not a Glucose-enriched Diet, Induces a Salt-dependent Increase in Blood Pressure and Enhances NKCC2 Phosphorylation in Normal Rats

Hypertension ◽

10.1161/hyp.66.suppl_1.142 ◽

2015 ◽

Vol 66 (suppl_1) ◽

Author(s):

Keyona N King-Medina ◽

Emily Henson ◽

Pablo Ortiz

Keyword(s):

Blood Pressure ◽

Drinking Water ◽

Salt Intake ◽

Caloric Intake ◽

High Salt ◽

Human Consumption ◽

Thick Ascending Limb ◽

Sprague Dawley ◽

High Fructose ◽

High Salt Intake

Human consumption of fructose as a sweetener has increased in the past 30 years. High fructose intake has been implicated in the development of hypertension, diabetes, and obesity. In the US, the upper 10th percentile of the population consumes up to 40% of their caloric intake from added sugars, in which fructose represents half of these. Fructose metabolism is strikingly different from that of glucose. Yet, the effect of a fructose or glucose-enriched diet in salt handling by the kidney, affecting blood pressure, and its interaction with high salt intake has been poorly studied. In genetic models of salt-sensitive hypertension, the activity of the Na + /K + /2Cl - cotransporter (NKCC2) in the thick ascending limb (TAL) is abnormally enhanced. We hypothesized that chronic fructose in drinking water induces a salt-dependent increase in blood pressure and stimulates NKCC2 during high salt intake in normal rats. Sprague-Dawley rats were given 20% fructose or 20% glucose in drinking water for 1 week after which a high salt (HS) diet (4% Na + in chow) was started for 3 weeks. When we measured systolic blood pressure (SBP) by tail cuff plethysmography in fructose-fed and glucose-fed rats on a HS diet, only the fructose-fed rats had an increased SBP from 120±10 to 132±6 mmHg on day 7 of HS (p<0.01). SBP continued to increase up to 144±18 mmHg after 3 weeks (p<0.01 vs glucose). Fructose or glucose alone did not increase SBP after 4 weeks. We then repeated the protocol using radiotelemetry to monitor the blood pressure (BP). In rats fed fructose, by day 5 of HS the SBP increased by 12±3 mmHg (p<0.02) and SBP remained elevated for 3 weeks (delta: 10±2.5 mmHg, n=3). In rats fed glucose, a HS diet did not significantly change SBP for 3 weeks (n=5). Moreover, NKCC2 activity in the TAL is enhanced by phosphorylation at Thr96, 101. We found that NKCC2 phosphorylation was higher in rats fed fructose plus HS (p<0.02) but not in rats fed glucose plus HS for 3 weeks (HS: 100, fructose+HS: 250±40%, glucose+HS: 95±10%). Therefore, we conclude that a high fructose (but not a glucose) diet in normal rats induces a salt-dependent increase in BP independently from caloric intake. Thus, the increase in BP may in part be due to the stimulation of NKCC2 phosphorylation in the TAL by fructose.

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The Relationship Between Urine Uromodulin and Blood Pressure Changes: The DASH-Sodium Trial

American Journal of Hypertension ◽

10.1093/ajh/hpaa140 ◽

2020 ◽

Author(s):

Christine Y Bakhoum ◽

Cheryl A M Anderson ◽

Stephen P Juraschek ◽

Casey M Rebholz ◽

Lawrence J Appel ◽

...

Keyword(s):

Blood Pressure ◽

Salt Intake ◽

Control Diet ◽

Random Order ◽

High Salt ◽

Thick Ascending Limb ◽

Feeding Period ◽

High Sodium ◽

Sodium Diet ◽

High Salt Intake

Abstract BACKGROUND Uromodulin modulates the sodium-potassium-two-chloride transporter in the thick ascending limb of the loop of Henle, and its overexpression in murine models leads to salt-induced hypertension. We hypothesized that individuals with higher baseline levels of urine uromodulin would have a greater increase in systolic blood pressure (SBP) for the same increase in sodium compared with those with lower uromodulin levels. METHODS We used data from 157 subjects randomized to the control diet of the Dietary Approaches to Stop Hypertension (DASH)-Sodium trial who were assigned to 30 days of low (1,500 mg/d), medium (2,400 mg/d), and high salt (3,300 mg/d) diets in random order. Blood pressure was measured prerandomization and then weekly during each feeding period. We evaluated the association of prerandomization urine uromodulin with change in SBP between diets, as measured at the end of each feeding period, using multivariable linear regression. RESULTS Baseline urine uromodulin stratified by tertiles was ≤17.64, 17.65–31.97, and ≥31.98 µg/ml. Across the tertiles, there were no significant differences in SBP at baseline, nor was there a differential effect of sodium diet on SBP across tertiles (low to high, P = 0.81). After adjusting for age, sex, body mass index, and race, uromodulin levels were not significantly associated with SBP change from low to high sodium diet (P = 0.42). CONCLUSIONS In a randomized trial of different levels of salt intake, higher urine uromodulin levels were not associated with a greater increase in blood pressure in response to high salt intake.

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Relationship Between Salt Intake and Blood Pressure in Hypertensive Patients in Beijing

American Journal of Hypertension ◽

10.1093/ajh/hpaa009 ◽

2020 ◽

Vol 33 (4) ◽

pp. 371-371

Author(s):

Hong-yi Wang ◽

Yong-jie He ◽

Wei Li ◽

Fan Yang ◽

Ning-ling Sun

Keyword(s):

Blood Pressure ◽

Ambulatory Blood Pressure ◽

Salt Intake ◽

Blood Pressure Monitoring ◽

Urinary Sodium Excretion ◽

High Salt ◽

Pressure Monitoring ◽

Hypertensive Patients ◽

High Salt Intake ◽

Tertiary Hospitals

Abstract Background To survey the relationship between salt intake and blood pressure in hypertensive patients in Beijing. Methods A cross-sectional survey was used. Essential hypertensive patients were enrolled and divided into three groups (low, medium, and high salt intake) according to their 24 h urinary sodium excretion, which was used to access the salt intake. Blood pressure was measured through office measurement and ambulatory blood pressure monitoring. Results A total of 2,241 patients were enrolled with a mean age of 59.5 ± 13.8 years, mean blood pressure of 141.1 ± 18.5/84.6 ± 12.7 mm Hg, and urinary sodium excretion of 163.9 (95% CI 160.3–167.4) mmol [equal to salt intake 9.59 (9.38–9.79) g/d]. There were 1,544 cases from tertiary hospitals and the other 697 cases from community hospitals. Patients from community hospitals took more salt than patients from tertiary hospitals. Patients with high salt intake were younger than patients with low and medium salt intake. There were more males in high salt intake group than in the other two groups. Ambulatory blood pressure monitoring showed that patients with high salt intake had higher mean blood pressure not only in daytime, but also at night. The diastolic blood pressure in patients with medium salt intake was higher than that in patients with low salt intake. Conclusions Higher salt intake was associated with higher ambulatory blood pressure in hypertensive patients. More effort should be made to lower salt intake to improve blood pressure control rate.

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