Effect of a salt restriction diet on cardiac damage in a rat model of metabolic syndrome
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ABSTRACT: We wanted to understand how a salt restriction diet could improve cardiac damage (ie cardiac hypertrophy, fibrosis, hypertension) in a rat model of metabolic syndrome. We thus performed an Agilent microarray experiment in order to identify expression variations in left ventricles of rats having a normal sodium diet (0,64%) or a low sodium diet (less than 0,01%)
Project description:In the present study we made use of the (1-renin) DOCA-salt mouse model - which has been previously shown to develop cardiac and renal hypertrophy - to evaluate the direct effects of high-salt diet on cardiac function and gene expression profiling. The comparison between low-salt and high-salt DOCA-treated mice will reveal what genes are directly modulated by sodium in (normotensive) DOCA-treated mice. Previous publications: Wang Q, Hummler E, Nussberger J, Clement S, Gabbiani G, Brunner HR, Burnier M. Blood pressure, cardiac, and renal responses to salt and deoxycorticosterone acetate in mice: role of renin genes. J Am Soc Nephrol. 2002;13:1509 –1516. Wang Q, Domenighetti AA, Pedrazzini T, Burnier M. Potassium supplementation reduces cardiac and renal hypertrophy independent of blood pressure in DOCA/salt mice. Hypertension. 2005 Sep;46(3):547-54. Keywords: comparative dose-response treatment (2 groups)
Project description:Sodium Chloride Inhibits Suppressive Function of Foxp3+ Regulatory T Cells Given the functional changes observed secondary to exposure to high-salt we wanted to know what expression based changes were taking place in the regulatory T cell population that might help to explain the evidenced functional deficits.
Project description:Serum and glucocorticoid-induced kinase 1 (SGK1) activates the epithelial sodium channel (eNaC) in tubules. We examined renal SGK1 abundance in salt-adaptation and in salt-sensitive hypertension. Sprague-Dawley and Dahl salt-sensitive rats were placed on either 8% or 0.3% NaCl diets for 10 days. Plasma aldosterone levels were approximately 2.5-fold greater on 0.3% versus 8% NaCl diets in both rat strains. Both serum and glucocorticoid-induced kinase 1 transcript and protein abundance were less (P<0.01) in Sprague-Dawley rats and greater (P<0.01) in Dahl salt-sensitive rats on 8% versus 0.3% NaCl diets. The cDNA sequences of serum and glucocorticoid-induced kinase 1 in both strains of rat were the same. The present results provide evidence that the abundance of serum and glucocorticoid-induced kinase 1 in rat kidney may play a role in salt adaptation and the pathogenesis of hypertension and suggests that aldosterone is not the primary inducer of SGK1 in the Sprague-Dawley rat. Keywords = Rattus norvegicus, Sprague Dawley, Dahl SS/Jr, kidney, NaCl diet Keywords: other
Project description:Diet induced obesity in rat was associated with myocardial dysfunction, hypertension and fibrosis. This study aimed to explore microRNA expression profiles in diet obesity-induced rat myocardium. Wistar rats were feed normal chow or high-fat diet for 20 weeks. After that, cardiac function was evaluated by echocardiography. Left ventricular myocardium was harvest to assess the extent of hypertension and fibrosis, meanwile, the left ventricular microRNA expression was analyzed using Agilent Rat miRNA microarray. Significant cardiac dysfunction, hypertension and fibrosis were found in diet-induced obesity rats as compared with normal diet rats. rno-miR-141-3p and rno-miR-144-3p were also significantly increased in myocardium of diet-induced obesity rat. These findings suggest that specific miRNA differences may contribute to the alteration in cardiac function, hypertension and fibrosis which responses to diet-induced obesity.
Project description:The inverse effects that dietary sodium and potassium have on blood pressure have been known for some time. High sodium consumption is detrimental, while potassium supplementation is known to be beneficial, and the ratio of sodium/potassium consumption is also very important to consider when determining how these electrolytes affect salt-induced hypertension; however, the mechanisms behind the beneficial effects of potassium are still not yet entirely established. Inwardly rectifying potassium (Kir) channels have been shown to play a major role in potassium transport and homeostasis in the kidney and might contribute to these effects. Here we aimed to examine how different variations in the sodium/potassium ratio affect the development of salt-sensitive hypertension and how channels and transporters in the kidney are altered to accommodate these changes. We hypothesize that these diets will affect the development of salt-sensitive hypertension, and that Kir channels will play a major role in the renal adaptations to varying intakes of potassium
Project description:Low salt diet is a constant recommendation to hypertensive patients. Here we investigated the impact of prolonged reduced sodium feeding on the geneomic fabrics responsible for heart contraction in adult male mice. Although only 166 (0.59%) of the 27901 quantified transcripts in all samples were significantly up- and 88 (0.32%) down-regulated, the synergistic coupling of the heart contraction genes increased by 22% while their antagonistic coupling decreased by 43%. This substantial remodeling of the heart contraction genomic fabric justifyes the low salt diet recommendation. Agilent mouse two-color gene expression arrays were used to profile the left heart ventricles of 16 weeks old C57Bl/6j male mice subjected for the last 8 weeks of their lives to normal (N, 0.4% Na) or low (L, 0.05%Na) salt diet. Differently labeled biological replicates were cohybridized with each array. Results of similarly labeled different conditions were compared then averaged for the two fluorescent labels. Thus, MW1 & MW3 were compared with MH1 & MH3, MW2 & MW4 were compared with MH2 & + MH4, and the results of the comparisons averaged. This design uses 100% of the resources, has a better normlaiztion and allows all possible comparisons among the conditions.
Project description:The overall objective of the study was to screen for microRNAs regulated by aldosterone and salt in rat left ventricles . Primary aldosteronism is characterized by excess aldosterone (ALDO) secretion independent of the renin-angiotensin system and accounts for ~10% of hypertensive patients. Excess ALDO, inappropriate for the salt intake status, causes cardiac hypertrophy, inflammation, fibrosis and hypertension. The molecular mechanisms that trigger the onset and progression of ALDO-mediated cardiac injury are poorly understood. MicroRNAs (miRNAs) are endogenous, small, non-coding RNAs that have been implicated in diverse cardiac pathologies, yet very little is known about their regulation and role in ALDO-mediated cardiac injury. To elucidate the regulation of miRNAs in ALDO-mediated cardiac injury, we performed a time-series analysis of left ventricle (LV) miRNA expression. Uninephrectomized male Sprague Dawley rats were treated with ALDO (0.75 µg/h) infusion and SALT (1.0% NaCl/0.3% KCl) in the drinking water for up to 8 weeks. ALDO/SALT time-dependently modulated the expression of multiple miRNAs in the LV. miR-21 was the most upregulated miRNA after 2 weeks of treatment and remained elevated until the end of the study. To elucidate the role of miR-21 in ALDO/SALT-mediated cardiac injury, miR-21 was downregulated using antagomirs in ALDO/SALT-treated rats. miR-21 downregulation exacerbated ALDO/SALT-mediated cardiac hypertrophy, fibrosis and inflammation markers gene expression, interstitial and perivascular fibrosis, OH-proline content and cardiac dysfunction. These results suggest that ALDO/SALT-mediated cardiac miR-21 upregulation may be a compensatory mechanism that mitigates ALDO/SALT-mediated cardiac deleterious effects. We speculate that miR-21 supplementation would have beneficial effects in reverting or mitigating cardiac injury and dysfunction in patients with primary aldosteronism.
Project description:Supporting microarray data for manuscript entitled "OSTEOPONTIN AND PAI-1 EXPRESSION IN MALIGNANT HYPERTENSION: SUPPRESSION BY p38 MAPK INHIBITORS" submitted to the HYPERTENSION journal. Keywords: timecourse, diet
Project description:Background. The Dahl salt-sensitive (SS) rat is an established model of salt-sensitive hypertension and renal damage. Recently, sodium-independent dietary effects were shown to be important in the development of the SS hypertensive phenotype. Compared to Dahl SS/JrHsdMcwi (SS/MCW) rats fed a purified diet (AIN-76A), grain-fed Dahl SS/JrHsdMcwiCrl rats (SS/CRL; Teklad 5L2F) were less susceptible to salt-induced hypertension and renal damage. Methods. With the known role of the immune system in hypertension, the present study characterized the immune cells infiltrating SS/MCW and SS/CRL kidneys. To further identify distinct molecular pathways between SS/MCW and SS/CRL, transcriptomic analysis was performed via RNA sequencing in T-cells isolated from the blood and kidneys of low and high salt-fed rats. Results. Following a 3-week high salt (4.0% NaCl) challenge, SS/CRL rats were protected from salt-induced hypertension (116.5±1.2 vs 141.9±14.4 mmHg) and albuminuria (21.7±3.5 vs 162.9±22.2 mg/day) compared to SS/MCW. Additionally, the absolute number of immune cells infiltrating the kidney was significantly reduced in SS/CRL. RNA-seq revealed >50% of all annotated genes in the entire transcriptome to be significantly differentially expressed in T-cells isolated from blood versus kidney. Pathway analysis of significant differentially expressed genes between SS/MCW and SS/CRL renal and circulating T-cells demonstrated salt-induced changes in genes related to inflammation in SS/MCW compared to metabolism-related pathways in SS/CRL. Conclusions. These functional and transcriptomic T-cell differences between SS/MCW and SS/CRL show that sodium-independent dietary effects may influence the immune response and infiltration of immune cells into the kidney, ultimately impacting susceptibility to salt-induced hypertension and renal damage.
Project description:Balb/cJ and C57BL/6J were subjected to either 0.5µg/kg/min angiotensin II, 3% sodium diet, or the combination. Sham operated animals receiving a 0.3% sodium normal diet were used as controls.