Effects of Renin-Angiotensin System Inhibitors on Renal Expression of Renalase in Sprague-Dawley Rats Fed With High Salt Diet

Abstract

Background/Aims: The aim of our study was to investigate the effect of high-salt diet on the renal expression of renalase and the potential role of the local renin-angiotensin system in this process. Methods: Sprague-Dawley (SD) rats were divided into groups according to salt content in diet and drug treatment as follows: normal-salt diet (NS), high-salt diet (HS), high-salt intake with hydralazine (HS+H), high-salt diet with enalapril (HS+E), and high-salt diet with valsartan (HS+V). The dietary intervention and drugs were given for four weeks. Renin activity and angiotensin II type 1 receptor (AT1R) levels were detected by real-time PCR. Renalase mRNA and protein were also measured. Results: After four weeks, systolic blood pressure and proteinuria were significantly increased in the HS group with respect to the NS group. Dietary salt intake caused a dramatic decrease in renalase expression in the rat kidneys. Renal cortex renin and AT1R increased significantly in the HS and HS+H groups. Urinary protein was positively correlated with renal renin and AT1R levels. However, in the HS+E and HS+V groups, enalapril and valsartan failed to influence renal renalase expression but abolished the increase in proteinuria, renal cortex renin, and AT1R levels with respect to the HS group. Conclusion: This study indicates that high salt intake reduces renal expression, and renal RAS may be not involved in the regulation of renalase in SD rats fed with high-salt diet.

High Sodium Intake Impairs Small Artery Vasoreactivity in vivo in Dahl Salt-Sensitive Rats

“…Many studies have focused on the relationship between local RAS activation and high sodium intake [37, 38], and some authors have concluded that high dietary salt induces the inappropriate activation of the local RAS [39]. In patients with hypertension, abnormal activation of circulatory RAS is responsible for the maintenance of high BP [40], while tissue RAS activation is closely related to the target organ damage and malfunction [41].…”

High Salt Diet Impacts the Risk of Sarcopenia Associated with Reduction of Skeletal Muscle Performance in the Japanese Population

“…Healthy adult volunteers ( n = 122, age (standard deviation [SD]): 56.3 (12.3) years) were recruited from the community using local advertisements, and participants were selected from Tsukuba and nearby urban areas (Ibaraki, Japan). Participants with an estimated glomerular filtration rate of 90 mL/min/1.73 m 2 or less were excluded because renal function is involved in sodium uptake and renalase levels [ 24 , 30 , 31 , 32 , 38 , 39 , 40 ]. In addition, eight participants who showed more than four times the standard deviation of the mean blood test of all 122 participants were excluded, because there was a possibility of other diseases.…”

Effects of Doenjang, a Traditional Korean Soybean Paste, with High-Salt Diet on Blood Pressure in Sprague–Dawley Rats

“…Changes in arterial pressure were not observed with the high-sodium diet, although levels of Ang II and aldosterone were lessened in the 4% and 8% NaCl groups [19]. However, Wang et al propose that renal RAAS action is independent or Versa of plasma RAA level at high salt intake, and improper activation of the RAAS in the kidney may contribute directly to hypertension and kidney damage [37]. Although the high-salt diet did not inhibit RAA level, doenjang lowered serum levels of renin and aldosterone in the present study.…”