Effects of a chronic high-salt diet on large artery structure: role of endogenous bradykinin

1998 ◽  
Vol 274 (5) ◽  
pp. H1423-H1428 ◽  
Author(s):  
Chohreh Partovian ◽  
Athanase Benetos ◽  
Jean-Pierre Pommiès ◽  
Willy Mischler ◽  
Michel E. Safar

Bradykinin activity could explain the blood pressure increase during NaCl loading in hypertensive animals, but its contribution on vascular structure was not evaluated. We determined cardiac mass and large artery structure after a chronic, 4-mo, high-salt diet in combination with bradykinin B2-receptor blockade by Hoe-140. Four-week-old rats were divided into eight groups according to strain [spontaneously hypertensive rats (SHR) vs. Wistar-Kyoto (WKY) rats], diet (0.4 vs. 7% NaCl), and treatment (Hoe-140 vs. placebo). In WKY rats, a high-salt diet significantly increased intra-arterial blood pressure with minor changes in arterial structure independently of Hoe-140. In SHR, blood pressure remained stable but 1) the high-salt diet was significantly associated with cardiovascular hypertrophy and increased arterial elastin and collagen, and 2) Hoe-140 alone induced carotid hypertrophy. A high-salt diet plus Hoe-140 acted synergistically on carotid hypertrophy and elastin content in SHR, suggesting that the role of endogenous bradykinin on arterial structure was amplified in the presence of a high-salt diet.

2019 ◽  
Vol 20 (14) ◽  
pp. 3495 ◽  
Author(s):  
Yanling Yan ◽  
Jiayan Wang ◽  
Muhammad A. Chaudhry ◽  
Ying Nie ◽  
Shuyan Sun ◽  
...  

We have demonstrated that Na/K-ATPase acts as a receptor for reactive oxygen species (ROS), regulating renal Na+ handling and blood pressure. TALLYHO/JngJ (TH) mice are believed to mimic the state of obesity in humans with a polygenic background of type 2 diabetes. This present work is to investigate the role of Na/K-ATPase signaling in TH mice, focusing on susceptibility to hypertension due to chronic excess salt ingestion. Age-matched male TH and the control C57BL/6J (B6) mice were fed either normal diet or high salt diet (HS: 2, 4, and 8% NaCl) to construct the renal function curve. Na/K-ATPase signaling including c-Src and ERK1/2 phosphorylation, as well as protein carbonylation (a commonly used marker for enhanced ROS production), were assessed in the kidney cortex tissues by Western blot. Urinary and plasma Na+ levels were measured by flame photometry. When compared to B6 mice, TH mice developed salt-sensitive hypertension and responded to a high salt diet with a significant rise in systolic blood pressure indicative of a blunted pressure-natriuresis relationship. These findings were evidenced by a decrease in total and fractional Na+ excretion and a right-shifted renal function curve with a reduced slope. This salt-sensitive hypertension correlated with changes in the Na/K-ATPase signaling. Specifically, Na/K-ATPase signaling was not able to be stimulated by HS due to the activated baseline protein carbonylation, phosphorylation of c-Src and ERK1/2. These findings support the emerging view that Na/K-ATPase signaling contributes to metabolic disease and suggest that malfunction of the Na/K-ATPase signaling may promote the development of salt-sensitive hypertension in obesity. The increased basal level of renal Na/K-ATPase-dependent redox signaling may be responsible for the development of salt-sensitive hypertension in polygenic obese TH mice.


2017 ◽  
Vol 313 (4) ◽  
pp. R425-R437 ◽  
Author(s):  
Bryan K. Becker ◽  
Amanda C. Feagans ◽  
Daian Chen ◽  
Malgorzata Kasztan ◽  
Chunhua Jin ◽  
...  

Hypertension is a prevalent pathology that increases risk for numerous cardiovascular diseases. Because the etiology of hypertension varies across patients, specific and effective therapeutic approaches are needed. The role of renal sympathetic nerves is established in numerous forms of hypertension, but their contribution to salt sensitivity and interaction with factors such as endothelin-1 are poorly understood. Rats deficient of functional ETB receptors (ETB-def) on all tissues except sympathetic nerves are hypertensive and exhibit salt-sensitive increases in blood pressure. We hypothesized that renal sympathetic nerves contribute to hypertension and salt sensitivity in ETB-def rats. The hypothesis was tested through bilateral renal sympathetic nerve denervation and measuring blood pressure during normal salt (0.49% NaCl) and high-salt (4.0% NaCl) diets. Denervation reduced mean arterial pressure in ETB-def rats compared with sham-operated controls by 12 ± 3 (SE) mmHg; however, denervation did not affect the increase in blood pressure after 2 wk of high-salt diet (+19 ± 3 vs. +16 ± 3 mmHg relative to normal salt diet; denervated vs. sham, respectively). Denervation reduced cardiac sympathetic-to-parasympathetic tone [low frequency-high frequency (LF/HF)] during normal salt diet and vasomotor LF/HF tone during high-salt diet in ETB-def rats. We conclude that the renal sympathetic nerves contribute to the hypertension but not to salt sensitivity of ETB-def rats.


2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Patience O Obih ◽  
Michael C Ezebuenyi ◽  
Akeem P Jimoh ◽  
John-Clifford A Obih

The objective of this study was to evaluate the impact of high-salt-diet on pioglitazone treated db/db mice. Groups of 6 weeks-old db/db mice obtained from Jackson Laboratory were given either pioglitazone (0.02%) in diet or pioglitazone (0.02%) plus high salt-diet (8% NaCl) for 6 to 12 weeks. Control groups received either pioglitazone or normal salt diet. During the course of treatment, urine volume, urine sodium, creatinine and blood glucose were measured in the animals. For urine collection, mice were placed in metabolic cages. In order to evaluate whether differences exist between diabetic animals that received pioglitazone or not in the handling of a sodium load and to characterize the transport mechanisms involved, at the end of experimental period the animals were given an acute sodium load (physiological saline), 1.25 ml/100 g body weight by intraperitoneal route. The sodium load was repeated in mice that was treated 15 minutes earlier with hydrochlorothiazide (40 mg/kg i.p.) or furosemide (8 mg/kg i.p.), or amiloride (1.65 mg/kg). The animals were placed in metabolic cages and urine voided was collected over 5 hr. for determination of urine volume and sodium. Sodium was determined by flame photometer. No significant changes were observed in mean arterial blood pressure in all the groups (at p 0.05). There was significant increase in UNav with all the diuretics in db/db mice that received high salt diet at 6 weeks. The blood pressure did not increase with the sodium diet. This might be due to natriuresis resulting from polyurea in the diabetic condition of the mice.


2011 ◽  
Vol 89 (4) ◽  
pp. 295-304 ◽  
Author(s):  
A.K. Oloyo ◽  
O.A. Sofola ◽  
C.N. Anigbogu

The effect of sex hormones on vascular reactivity is considered one of the underlying factors contributing to gender differences in cardiovascular functions and diseases. Experiments were designed to investigate the role of androgens in salt-induced hypertension by assessing the relaxation response of isolated aortic rings to acetylcholine and sodium nitroprusside in the presence or absence of l-nitroarginine methyl ester in Sprague–Dawley rats. The rats were either orchidectomized or sham-operated, with or without testosterone replacement, and were placed on a normal or high-salt diet for 6 weeks. The results indicate a significant increase (p < 0.001) in the mean arterial blood pressure of rats on the high-salt diet, when compared with control or orchidectomized rats. Orchidectomy elicited a reduction in mean arterial blood pressure (p < 0.01), while testosterone replacement normalized mean arterial blood pressure to values seen in intact rats on the high-salt diet. The high-salt diet reduced the relaxation response to acetylcholine both in the presence and absence of inhibition of endothelial nitric oxide synthase with l-nitroarginine methyl ester. Bilateral orchidectomy attenuated the impaired endothelial function induced by the high-salt diet in rats, but this was reversed by concomitant administration of testosterone, suggesting a role for androgens in enhancing long-term vascular smooth muscle tone and hence maintenance of high blood pressure in salt-induced hypertension.


Hypertension ◽  
2013 ◽  
Vol 62 (suppl_1) ◽  
Author(s):  
Mingyu Liang ◽  
Chun Yang ◽  
Christine B Peterson ◽  
Pengyuan Liu ◽  
Francesco C Stingo ◽  
...  

Previous analysis of 13 overlapping subcongenic strains led to the identification of a 1.37 Mbp region on chromosome 13 (positions 80.92 to 82.29 Mbp in the Rn5 genome assembly) that influenced the mean arterial blood pressure of the Dahl salt-sensitive (SS) rat on a high-salt diet by more than 20 mmHg. The goal of the present study was to identify biological pathways that could mediate the blood pressure effect of this genomic region. RNA-seq analysis was performed for the renal outer medulla tissue in five selected subcongenic strains, the SS, and a congenic strain from which the subcongenic strains were derived. Rats were fed a 0.4% salt diet or switched to a high-salt diet for 7 days. Affymetrix GeneChip data for SS and three additional congenic or consomic strains were obtained from a previous study. The RNA-seq and microarray data were merged using a cross-platform normalization method to generate a transcriptome dataset containing 90 observations for each gene. A Bayesian model analysis was performed for 243 biological pathways to assess their likelihood to discriminate blood pressure levels across experimental groups. Seven pathways showed posterior probabilities greater than 0.4. These pathways involved neuroactive ligand-receptor interaction, phenylalanine, tyrosine and tryptophan biosynthesis, and protein degradation. A Bayesian approach was used to estimate undirected graphical models among the three known genes located in the 1.37 Mbp region (Astn1, Fam5b, and Rfwd2) and genes in each of the 7 pathways identified above and 11 additional pathways known to be involved in blood pressure regulation. The analysis identified several previously unknown relationships between the three candidate genes and genes in pathways that could regulate blood pressure. The study demonstrated a new, unbiased approach for identifying biological pathways mediating the effect of a candidate genomic region on hypertension.


Hypertension ◽  
2015 ◽  
Vol 66 (suppl_1) ◽  
Author(s):  
Nuno Pires ◽  
Bruno Igreja ◽  
Eduardo Moura ◽  
Maria João Bonifácio ◽  
Paula Serrão ◽  
...  

Loss of salt-inducible kinase 1 (SIK1) triggers an increase in blood pressure (BP) upon a chronic high-salt intake in mice (Circ Res 2015;116:642-52). Here, we address possible acute mechanisms that may relate to the observed high BP in mice lacking SIK1. SIK1 knockout ( sik1 -/- ) and wild-type ( sik1 +/+ ) littermate mice were challenged for seven days with a normal- (0.3% NaCl) or high-salt (8% NaCl) diet. Systolic BP (SBP) was significantly increased in sik1 -/- mice (137.0±17.2 mmHg) after seven days of high-salt intake, as compared to sik1 +/+ mice counterparts (120.6±4.5 mmHg). The renin-angiotensin system (RAS) and the sympathetic nervous system (SNS) were assayed in order to investigate the possible causes for the increase in SBP in sik1 -/- mice fed a high-salt diet. No differences in renin (normal-salt: 463.4±17.9, high-salt: 462.9±28.9 pg/ml) and angiotensin II (normal-salt: 45.8±10.0, high-salt: 39.0±8.5 pg/ml) serum levels were observed. The activity of dopamine β-hydroxylase (DβH), the enzyme that converts dopamine (DA) to norepinephrine (NE), was significantly increased in the adrenal glands of sik1 -/- mice fed a high-salt diet (356.7±32.8 nmol/mg protein) as compared to sik1 -/- mice on a normal-salt diet (184.4±14.4 nmol/mg protein). Similarly, urinary catecholamines (DA, NE, epinephrine) and L-DOPA were significantly increased (3- to 7-fold increase) in sik1 -/- mice fed a high-salt diet as compared to sik1 -/- mice on a normal-salt intake. Altogether, this data supports the view that sik1 -/- mice fed a high-salt diet develop SNS overactivity. Next, we addressed the question if reducing SNS activity in sik1 -/- mice fed a high-salt diet would ameliorate hypertension. For that purpose, the effect of etamicastat, a peripheral reversible DβH inhibitor, was evaluated on the development of high BP upon high-salt diet. Etamicastat treatment (50 mg/kg/day), started prior to high-salt feeding, completely prevented SBP increase in sik1 -/- mice fed a high-salt diet (116.8±4.7 mmHg). It is concluded that the SNS is involved in the development of salt-induced hypertension in sik1 -/- mice and that the DβH inhibitor etamicastat is able to reduce SNS overactivity and high BP in this mouse model of hypertension.


1973 ◽  
Vol 45 (s1) ◽  
pp. 135s-139s ◽  
Author(s):  
G. Bianchi ◽  
U. Fox ◽  
G. F. Di Francesco ◽  
U. Bardi ◽  
Maria Radice

1. Spontaneously hypertensive and normotensive rats were selectively bred from a single Wistar strain. 2. Cross-transplantation of kidneys from hypertensive to normotensive rats and vice versa was performed, the sole remaining kidney of the recipient later being excised. Kidneys were also transplanted from normotensive donors into normotensive recipients and from hypertensive to hypertensive. 3. Normotensive rats receiving a kidney from either a hypertensive or normotensive donor showed unchanged blood pressure on normal salt diet. High-salt diet produced a greater rise in recipients of hypertensive than in recipients of normotensive kidneys. 4. Normotensive kidneys reduced the blood pressure of hypertensive recipients, but transplanted hypertensive kidneys had no such effect.


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