Angiotensin II promotes aortic valve thickening independent of elevated blood pressure in apolipoprotein-E deficient mice

Objective: Chronic infusion of angiotensin II (AngII) promotes development of abdominal aortic aneurysms (AAAs) in hypercholesterolemic mice. Previous studies have shown that local inflammation and increased oxidative stress plays an important role on formation of AAAs. In addition, it is reported that voltage-dependent N-type Ca2+ channels in endothelial cells contribute to oxidative stress-related endothelial dysfunction induced by AngII in mice. Therefore, we hypothesized that cilnidipine, an N/L-type calcium channel blocker, exerts vasoprotective effect by inhibiting inflammation and superoxide generation in mice. The purpose of this study was to evaluate whether cilnidipine influenced AngII-induced AAAs. Methods and Results: Male apolipoprotein E deficient mice (8-12 weeks old) were fed a normal laboratory diet. Mice were infused subcutaneously with either cilnidipine or vehicle by osmotic minipumps. Three days later, mice were also infused subcutaneously with either AngII (1,000 ng/kg/min, n = 14-16) or saline (n = 4) each by osmotic minipumps for 4 weeks. AngII increased systolic blood pressure. Cilnidipine decreased blood pressure in AngII-infused mice, but had not effect during saline infusion. AngII infusion did not alter serum cholesterol concentrations. However, cilnidipine slightly decreased serumcholesterol concentrations in AngII-infused mice. Cilnidipine had no effect on body weights, heart rates, and urine total protein, but mildly restored plasma renin activity that were suppressed by AngII infusion. Cilnidipine did not affect ex vivo measurement of maximal diameter of abdominal aorta (1.04 ± 0.09 mm vs 1.11 ± 0.06 mm, n.s.) in saline infused mice. AngII infusion significantly increased ex vivo maximal diameters of abdominal aortas, but was attenuated by cilnidipine (1.79 ± 0.59 mm vs 1.26 ± 0.38 mm, P < 0.05). In addition, cilnidipine significantly reduced the incidence of AngII-induced AAAs (Cilnidipine: 38 %, Vehicle: 88 %; P < 0.05). Furthermore, gelatin zymography demonstrated that cilnidipine diminished AngII-induced increase in aortic MMP-9 protein abundance. Conclusion: Cilnidipine attenuated AngII-induced AAAs in male apolipoprotein E deficient mice.

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Norepinephrine Transporter–Deficient Mice Exhibit Excessive Tachycardia and Elevated Blood Pressure With Wakefulness and Activity

Circulation ◽

10.1161/01.cir.0000141804.90845.e6 ◽

2004 ◽

Vol 110 (10) ◽

pp. 1191-1196 ◽

Cited By ~ 41

Author(s):

Nancy R. Keller ◽

André Diedrich ◽

Martin Appalsamy ◽

Sunti Tuntrakool ◽

Suzanna Lonce ◽

...

Keyword(s):

Blood Pressure ◽

Norepinephrine Transporter ◽

Elevated Blood Pressure ◽

Elevated Blood ◽

Deficient Mice

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Renal Natriuretic Peptide Receptor-C Deficiency Attenuates NaCl Cotransporter Activity in Angiotensin II–Induced Hypertension

Hypertension ◽

10.1161/hypertensionaha.120.15636 ◽

2021 ◽

Vol 77 (3) ◽

pp. 868-881

Author(s):

Shuai Shao ◽

Xiao-Dong Li ◽

Yuan-Yuan Lu ◽

Shi-Jin Li ◽

Xiao-Hui Chen ◽

...

Keyword(s):

Blood Pressure ◽

Angiotensin Ii ◽

Natriuretic Peptide ◽

Elevated Blood Pressure ◽

Natriuretic Peptide Receptor ◽

Sodium Retention ◽

Ang Ii ◽

Elevated Blood ◽

Peptide Receptor ◽

Induced Hypertension

Genome-wide association studies have identified that NPR-C (natriuretic peptide receptor-C) variants are associated with elevation of blood pressure. However, the mechanism underlying the relationship between NPR-C and blood pressure regulation remains elusive. Here, we investigate whether NPR-C regulates Ang II (angiotensin II)-induced hypertension through sodium transporters activity. Wild-type mice responded to continuous Ang II infusion with an increased renal NPR-C expression. Global NPR-C deficiency attenuated Ang II–induced increased blood pressure both in male and female mice associated with more diuretic and natriuretic responses to a saline challenge. Interestingly, Ang II increased both total and phosphorylation of NCC (NaCl cotransporter) abundance involving in activation of WNK4 (with-no-lysine kinase 4)/SPAK (Ste20-related proline/alanine-rich kinase) which was blunted by NPR-C deletion. NCC inhibitor, hydrochlorothiazide, failed to induce natriuresis in NPR-C knockout mice. Moreover, low-salt and high-salt diets–induced changes of total and phosphorylation of NCC expression were normalized by NPR-C deletion. Importantly, tubule-specific deletion of NPR-C also attenuated Ang II–induced elevated blood pressure, total and phosphorylation of NCC expression. Mechanistically, in distal convoluted tubule cells, Ang II dose and time-dependently upregulated WNK4/SPAK/NCC kinase pathway and NPR-C/Gi/PLC/PKC signaling pathway mediated NCC activation. These results demonstrate that NPR-C signaling regulates NCC function contributing to sodium retention-mediated elevated blood pressure, which suggests that NPR-C is a promising candidate for the treatment of sodium retention-related hypertension.

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Abstract 104: Cilnidipine Attenuated Angiotensin II-induced Abdominal Aortic Aneurysms in Apolipoprotein E-deficient Mice via Its Anti-oxidative Stress Effect

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.36.suppl_1.104 ◽

2016 ◽

Vol 36 (suppl_1) ◽

Author(s):

Yuki Kakio ◽

Haruhito A Uchida ◽

Ryoko Umebayashi ◽

Jun Wada

Keyword(s):

Oxidative Stress ◽

Blood Pressure ◽

Angiotensin Ii ◽

Apolipoprotein E ◽

Abdominal Aortic Aneurysms ◽

Aortic Aneurysms ◽

Stress Effect ◽

Osmotic Minipumps ◽

Abdominal Aortic ◽

Deficient Mice

Objective: Chronic angiotensin II (AngII) infusion promotes development of abdominal aortic aneurysms (AAAs) in hypercholesterolemic mice. Previous studies have shown that local inflammation and increased oxidative stress plays an important role on formation of AAAs. In addition, voltage-dependent N-type Ca 2+ channels in endothelial cells contribute to oxidative stress-related endothelial dysfunction induced by AngII in mice. Last year, we reported that cilnidipine, an N/L-type calcium channel blocker, attenuated AngII-induced AAAs in apolipoprotein E deficient mice. The purposed of this study was to determine the mechanism of cilnidipine reducing AngII-induced AAAs Methods and Results: Male apolipoprotein E deficient mice (8-12 weeks old) were fed a normal laboratory diet. Mice were infused subcutaneously with either cilnidipine or vehicle by osmotic minipumps. Three days later, mice were also infused subcutaneously with either AngII (1,000 ng/kg/min, n = 14-16) or saline (n = 4) by osmotic minipumps for 4 weeks. AngII increased systolic blood pressure. Cilnidipine decreased blood pressure in AngII-infused mice, but had not effect during saline infusion. Cilnidipine mildly restored plasma renin activity that were suppressed by AngII infusion. Cilnidipine mildly decreased plasma aldosterone concentrations that were increased by AngII infusion. Cilnidipine significantly reduced the incidence of AngII-induced AAAs (cilnidipine: 38 %, Vehicle: 88 %; P < 0.05). Elastica van Gieson staining demonstrated degeneration of elastic lamina by AngII was suppressed by cilnidipine administration. Immunohistochemical staining of CD68 revealed that cilnidipine administration attenuated accumulation of CD68 positive macrophage by AngII. In addition, cilnidipine reduced oxidative stress by AngII in 8-hydroxy-2’-deoxyguanosine and 4-Hydroxy-2-nonenal staining. Conclusion: Cilnidipine attenuated AngII-induced AAAs in male apolipoprotein E deficient mice by its anti-inflammation and anti-oxidative stress effect.

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The effects of phentolamine on fructose-fed rats

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y2012-063 ◽

2012 ◽

Vol 90 (8) ◽

pp. 1075-1085 ◽

Cited By ~ 5

Author(s):

Kangbin Zhou ◽

Ujendra Kumar ◽

Violet G. Yuen ◽

John H. McNeill

Keyword(s):

Blood Pressure ◽

Uric Acid ◽

Angiotensin Ii ◽

Plasma Levels ◽

Elevated Blood Pressure ◽

Elevated Blood ◽

Medical Disorders ◽

Dietary Fructose ◽

Plasma Nitrate

Metabolic syndrome (MS) is a combination of medical disorders that increase the risk of developing cardiovascular disease and diabetes. MS is associated with obesity, increased blood pressure, hyperlipidemia, and hyperglycemia. This study was designed to investigate the pharmacological profile of phentolamine, a nonselective α adrenergic receptor antagonist, in the prevention of increased blood pressure in fructose-fed rats. Phentolamine prevented the fructose-induced increase in systolic blood pressure without affecting insulin sensitivity and major metabolic parameters. The levels of plasma noradrenaline and angiotensin II, 2 proposed contributors to the development of fructose-induced elevated blood pressure, were examined. Neither noradrenaline nor angiotensin II levels were affected by phentolamine treatment. Since overproduction of nitric oxide has been shown to lead to an elevation in peroxynitrite, the role of oxidative stress, a proposed mechanism of fructose-induced elevated blood pressure and insulin resistance, was examined by measuring plasma levels of total nitrate/nitrite. Plasma nitrate/nitrite was significantly elevated in all fructose-fed animals, regardless of treatment with phentolamine. Another proposed contributor toward fructose-induced MS is an elevation in uric acid levels. In this experiment, plasma levels of uric acid were found to be increased by dietary fructose and were unaffected by phentolamine treatment.

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