Perinatal Delivery of Angiotensin Type 2 Receptor (AT2R) Antisense cDNA Increases Blood Pressure in Adult Normotensive Rats

Hypertension ◽  
2000 ◽  
Vol 36 (suppl_1) ◽  
pp. 690-690
Author(s):  
Michael J Katovich ◽  
Hongwei Wang ◽  
Stephan Gallinat ◽  
Colin Sumners ◽  
Mohan K Raizada
Keyword(s):  
Blood Pressure ◽  
Ang Ii ◽  
Sprague Dawley ◽  
Antisense Gene ◽  
Maximal Increase ◽  
Viral Particles ◽  
Angiotensin Type 2 Receptor ◽  
High Degree

71 Recent observations suggest that AT 2 R have a role in the counter-regulatory actions of angiotensin II (Ang II) in cardiovascular protection and angiogenesis. The objective of the current investigation was to provide evidence for this cardioprotective action of AT 2 R by utilizing antisense gene transfer technology in normotensive rats. A retroviral vector containing full length AT 2 receptor antisense cDNA (LNSV-AT 2 R-AS) or missense (LNSV-AT 2 R-MS) was constructed. The LNSV-AT 2 R-AS viral particles were highly efficient in the transduction of AT 2 R-AS in vitro . The efficacy and effectiveness of this transduction was demonstrated by the long-lasting expression of AT 2 R-AS transcript and a decrease in AT 2 R binding. In vivo administration of LNSV-AT 2 R-AS resulted in similar findings. Five-day old normotensive Sprague Dawley rats received a single intracardiac bolus (25 μl) administration of LNSV-AT 2 R-AS viral particles (1x10 9 cfu/ml), which resulted in a robust expression of AT 2 R-AS transcript in tissues such as heart, kidney, adrenals and brain as early as five days post-delivery. Control rats received either LNSV alone or LNSV-AT 2 R-MS under identical conditions. The expression of AT 2 R-AS was persistent through adulthood indicating a high degree of transgene transduction in vivo . Mean blood pressure (BP) was elevated in the adult LNSV-AT 2 R-AS-treated rats when compared to the age-matched LNSV-AT 2 R-MS or control rats (123±5 mmHg vs. 100±9 mmHg). In addition, the pressor responses produced by Ang I and Ang II were enhanced in the LNSV-AT 2 R-AS- treated rats. For example, administration of 0.1 μg/Kg Ang I elicited a maximal increase in BP of 35±6 mmHg in the LNSV-AT 2 R-AS-treated rats compared to an increase of 23±6 mmHg in the LNSV-AT 2 R-MS. These observations demonstrate for the first time, that persistant inhibition of AT 2 R in normotensive rats influence cardiovascular responsiveness. Collectively, these data suggest that use of the AT 1 receptor antagonist-based therapy, with the resultant increase in Ang II levels, might provide additional benefit to the hypertensive patient via increased AT 2 R stimulation.

Abstract MP03: ROCK2 Specific Inhibition Attenuates Angiotensin II-induced Hypertension In Mice

Hypertension ◽  
2021 ◽  
Vol 78 (Suppl_1) ◽  
Author(s):  
Daniel J Fehrenbach ◽  
Meena S Madhur
Keyword(s):  
Blood Pressure ◽  
T Cell ◽  
Angiotensin Ii ◽  
Repeated Measures ◽  
Flow Cytometric Analysis ◽  
Coiled Coil ◽  
Ang Ii ◽  
Induced Hypertension

Hypertension, or an elevated blood pressure, is the primary modifiable risk factor for cardiovascular disease, the number one cause of mortality worldwide. We previously demonstrated that Th17 activation and interleukin 17A (IL-17A)/IL-21 production is integral for the full development of a hypertensive phenotype as well as the renal and vascular damage associated with hypertension. Rho-associated coiled-coil containing protein Kinase 2 (ROCK2) serves as a molecular switch upregulating Th17 and inhibiting regulatory T cell (Treg) differentiation. We hypothesize that hypertension is characterized by excessive T cell ROCK2 activation leading to increased Th17/Treg ratios and ultimately end-organ damage. We first showed in vitro that KD025, an experimental orally bioavailable ROCK2 inhibitor inhibits Th17 cell proliferation and IL-17A/IL-21 production. To determine if hypertensive stimuli such as endothelial stretch increases T cell ROCK2 expression, we cultured human aortic endothelial cells exposed to 5% (normotensive) or 10% (hypertensive) stretch with circulating human T cells and HLA-DR+ antigen presenting cells. Hypertensive stretch increased T cell ROCK2 expression 2-fold. We then tested the effect of ROCK2 inhibition with KD025 (50mg/kg i.p. daily) in vivo on angiotensin II (Ang II)-induced hypertension. Treatment with KD025 significantly attenuated the hypertensive response within 1 week of Ang II treatment (systolic blood pressure: 139± 8 vs 108±7mmHg) and this persisted for the duration of the 4 week study reaching blood pressures 20 mmHg lower (135±13mmHg) than vehicle treated mice (158±4mmHg p<0.05 effect of treatment 2-way Repeated Measures ANOVA). Flow cytometric analysis of tissue infiltrating leukocytes revealed that KD025 treatment increased Treg/Th17 ratios in the kidney (0.61±0.03 vs 0.79±0.08, p<0.05 student’s t-test). Thus, T cell ROCK2 may be a novel therapeutic target for the treatment of hypertension.

Vascular smooth muscle function of renal glomerular and interlobar arteries predicts renal damage in rats

2012 ◽  
Vol 303 (8) ◽  
pp. F1187-F1195 ◽  
Author(s):  
Peter Vavrinec ◽  
Robert H. Henning ◽  
Maaike Goris ◽  
Diana Vavrincova-Yaghi ◽  
Hendrik Buikema ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Intravital Microscopy ◽  
Renal Damage ◽  
Renal Arteries ◽  
Ang Ii ◽  
Vascular Integrity ◽  
Relative Expression ◽  
Glomerular Arterioles

Previously, it was shown that individuals with good baseline (a priori) endothelial function in isolated (in vitro) renal arteries developed less renal damage after ⅚ nephrectomy (5/6Nx; Gschwend S, Buikema H, Navis G, Henning RH, de Zeeuw D, van Dokkum RP. J Am Soc Nephrol 13: 2909–2915, 2002). In this study, we investigated whether preexisting glomerular vascular integrity predicts subsequent renal damage after 5/6Nx, using in vivo intravital microscopy and in vitro myogenic constriction of small renal arteries. Moreover, we aimed to elucidate the role of renal ANG II type 1 receptor (AT1R) expression in this model. Anesthetized rats underwent intravital microscopy to visualize constriction to ANG II of glomerular afferent and efferent arterioles, with continuous measurement of blood pressure, heart rate, and renal blood flow. Thereafter, 5/6Nx was performed, interlobar arteries were isolated from the extirpated kidney, and myogenic constriction was assessed in a perfused vessel setup. Blood pressure and proteinuria were assessed weekly for 12 wk, and focal glomerulosclerosis (FGS) was determined at the end of study. Relative expression AT1R in the kidney cortex obtained at 5/6Nx was determined by PCR. Infusion of ANG II induced significant constriction of both afferent and efferent glomerular arterioles, which strongly positively correlated with proteinuria and FGS at 12 wk after 5/6Nx. Furthermore, in vitro measured myogenic constriction of small renal arteries negatively correlated with proteinuria 12 wk after 5/6Nx. Moreover, in vivo vascular reactivity negatively correlated with in vitro reactivity. Additionally, relative expression of AT1R positively correlated with responses of glomerular arterioles and with markers of renal damage. Both in vivo afferent and efferent responses to ANG II and in vitro myogenic constriction of small renal arteries in the healthy rat predict the severity of renal damage induced by 5/6Nx. This vascular responsiveness is highly dependent on AT1R expression. Intraorgan vascular integrity may provide a useful tool to guide the prevention and treatment of renal end-organ damage.

scholarly journals Autophagy inhibition by chloroquine prevents increase in blood pressure and preserves endothelial functions

2020 ◽  
Vol 19 (4) ◽  
pp. 789-796
Author(s):  
Moon Jain ◽  
Hina Iqbal ◽  
Pankaj Yadav ◽  
Himalaya Singh ◽  
Debabrata Chanda ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Cell Migration ◽  
Endothelial Cell ◽  
Angiotensin Ii ◽  
Ang Ii ◽  
Hypertensive Rats ◽  
Autophagy Flux ◽  
Endothelial Functions

Purpose: To determine the effects of lysosomal inhibition of autophagy by chloroquine (CHQ) onhypertension-associated changes in the endothelial functions. Method: Angiotensin II (Ang II)-treated human endothelial cell line EA.hy926 and renovascularhypertensive rats were subjected to CHQ treatment (in vitro: 0.5, 1, and 2.5 μM; in vivo: 50 mg/kg/dayfor three weeks). Changes in the protein expressions of LC3b II (autophagosome formation marker) andp62 (autophagy flux marker) were assessed using immunoblotting. Cell migration assay, tubuleformation assay (in vitro), and organ bath studies (in vivo) were performed to evaluate the endothelialfunctions. Hemodynamic parameters were measured as well. Results: A higher expression of LC3b II and a reduced expression of p62 observed in the Ang II-treatedendothelial cells, as well as in the aorta of the hypertensive rats, indicated enhanced autophagy.Treatment with CHQ resulted in reduced autophagy flux (in vitro as well as in vivo) and suppressed AngII-induced endothelial cell migration and angiogenesis (in vitro). The treatment with CHQ was alsoobserved to prevent increase in blood pressure in hypertensive rats and preserved acetylcholineinducedrelaxation in phenylephrine-contracted aorta from the hypertensive rats. In addition, chloroquineattenuated Ang II-induced contractions in the aorta of normotensive as well as hypertensive rats. Conclusion: These observations indicated that CHQ lowers the blood pressure and preserves thevascular endothelial function during hypertension. Keywords: Angiotensin II, Autophagy, Chloroquine, Endothelial function, Hypertension, Vasculardysfunction

Enhanced skeletal muscle arteriolar reactivity to ANG II after recovery from ischemic acute renal failure

2005 ◽  
Vol 289 (6) ◽  
pp. R1770-R1776 ◽  
Author(s):  
David P. Basile ◽  
Deborah L. Donohoe ◽  
Shane A. Phillips ◽  
Jefferson C. Frisbee
Keyword(s):  
Skeletal Muscle ◽  
Renal Failure ◽  
Acute Renal Failure ◽  
Pressor Response ◽  
Gracilis Muscle ◽  
Ang Ii ◽  
Sprague Dawley

In addition to the long-term renal complications, previous studies suggested that after acute renal failure (ARF), rats manifest an increased pressor response to an overnight infusion of ANG II. The present study tested whether recovery from ARF results in alterations in sensitivity to the peripheral vasculature. ARF was induced in Sprague-Dawley rats by 45 min of bilateral renal ischemia and reperfusion. Animals were allowed to recover renal structure and function for 5–8 wk, after which the acute pressor responses to ANG II were evaluated either in vivo in in situ skeletal muscle arterioles or in isolated gracilis muscle arteries in vitro. Baseline arterial pressure was not different in ARF rats vs. sham-operated controls, although ARF rats exhibited an enhanced pressor response to bolus ANG II infusion compared with control rats. Steady-state plasma ANG II concentration and plasma renin activity were similar between ARF and control rats. Constrictor reactivity of in situ cremasteric arterioles from ARF rats was enhanced in response to increasing concentrations of ANG II; however, no difference was observed in arteriolar responses to elevated Po2, norepinephrine, acetylcholine, or sodium nitroprusside. Isolated gracilis muscle arteries from ARF rats also showed increased vasoconstriction in response to ANG II but not norepinephrine. In conclusion, recovery from ischemic ARF is not associated with hypertension but is associated with increased arteriolar constrictor reactivity to ANG II. Although the mechanisms of this altered responsiveness are unclear, such changes may relate, in part, to cardiovascular complications in patients with ARF and/or after renal transplant.

scholarly journals Effect of renin inhibition and AT1R blockade on myocardial remodeling in the transgenic Ren2 rat

2008 ◽  
Vol 295 (1) ◽  
pp. E103-E109 ◽  
Author(s):  
Adam Whaley-Connell ◽  
Javad Habibi ◽  
Shawna A. Cooper ◽  
Vincent G. DeMarco ◽  
Melvin R. Hayden ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Blood Pressure ◽  
Nadph Oxidase ◽  
Oxidase Activity ◽  
Myocardial Remodeling ◽  
Ang Ii ◽  
Sprague Dawley ◽  
Nadph Oxidase Activity ◽  
Renin Inhibition

Angiotensin II (Ang II) stimulation of the Ang type 1 receptor (AT1R) facilitates myocardial remodeling through NADPH oxidase-mediated generation of oxidative stress. Components of the renin-angiotensin system constitute an autocrine/paracrine unit in the myocardium, including renin, which is the rate-limiting step in the generation of Ang II. This investigation sought to determine whether cardiac oxidative stress and cellular remodeling could be attenuated by in vivo renin inhibition and/or AT1R blockade in a rodent model of chronically elevated tissue Ang II levels, the transgenic (mRen2)27 rat (Ren2). The Ren2 overexpresses the mouse renin transgene with resultant hypertension, insulin resistance, and cardiovascular damage. Young (6- to 7-wk-old) heterozygous (+/−) male Ren2 and age-matched Sprague-Dawley rats were treated with the renin inhibitor aliskiren, which has high preferential affinity for human and mouse renin, an AT1R blocker, irbesartan, or placebo for 3 wk. Myocardial NADPH oxidase activity and immunostaining for NADPH oxidase subunits and 3-nitrotyrosine were evaluated and remodeling changes assessed by light and transmission electron microscopy. Blood pressure, myocardial NADPH oxidase activity and subunit immunostaining, 3-nitrotyrosine, perivascular fibrosis, mitochondrial content, and markers of activity were significantly increased in Ren2 compared with SD littermates. Both renin inhibition and blockade of the AT1R significantly attenuated cardiac functional and structural alterations, although irbesartan treatment resulted in greater reductions of both blood pressure and markers of oxidative stress. Collectively, these data suggest that both reduce changes driven, in part, by Ang II-mediated increases in NADPH oxidase and, in part, increases in blood pressure.

scholarly journals Contribution of cytochrome P-450 4A1 and 4A2 to vascular 20-hydroxyeicosatetraenoic acid synthesis in rat kidneys

1999 ◽  
Vol 276 (2) ◽  
pp. F246-F253 ◽  
Author(s):  
Mong-Heng Wang ◽  
Hui Guan ◽  
Xuandai Nguyen ◽  
Barbara A. Zand ◽  
Alberto Nasjletti ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Rat Kidney ◽  
Acid Synthesis ◽  
Biologically Active ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Antisense Odns ◽  
Cytochrome P 450

20-Hydroxyeicosatetraenoic acids (20-HETE), a biologically active cytochrome P-450 (CYP) metabolite of arachidonic acid in the rat kidney, can be catalyzed by CYP4A isoforms including CYP4A1, CYP4A2, and CYP4A3. To determine the contribution of CYP4A isoforms to renal 20-HETE synthesis, specific antisense oligonucleotides (ODNs) were developed, and their specificity was examined in vitro in Sf9 cells expressing CYP4A isoforms and in vivo in Sprague-Dawley rats. Administration of CYP4A2 antisense ODNs (167 nmol ⋅ kg body wt−1 ⋅ day−1iv for 5 days) decreased vascular 20-HETE synthesis by 48% with no effect on tubular synthesis, whereas administration of CYP4A1 antisense ODNs inhibited vascular and tubular 20-HETE synthesis by 52 and 40%, respectively. RT-PCR of microdissected renal microvessel RNA indicated the presence of CYP4A1, CYP4A2, and CYP4A3 mRNAs, and a CYP4A1-immunoreactive protein was detected by Western analysis of microvessel homogenates. Blood pressure measurements revealed a reduction of 17 ± 6 and 16 ± 4 mmHg in groups receiving CYP4A1 and CYP4A2 antisense ODNs, respectively. These studies implicate CYP4A1 as a major 20-HETE synthesizing activity in the rat kidney and further document the feasibility of using antisense ODNs to specifically inhibit 20-HETE synthesis and thereby investigate its role in the regulation of renal function and blood pressure.

Abstract 020: Angiotensin Ii-induced Hypertension Has Significant Effects On Proliferation, Differentiation And Engraftment Efficacy Of Hematopoietic Stem Cell.

Hypertension ◽  
2014 ◽  
Vol 64 (suppl_1) ◽  
Author(s):  
Seungbum Kim ◽  
Christopher R Cogle ◽  
Michael Zingler ◽  
Edward W Scott ◽  
Mohan K Raizada
Keyword(s):  
Blood Pressure ◽  
Stem Cell ◽  
Hematopoietic Stem Cell ◽  
Inflammatory Cells ◽  
Time Lapse ◽  
Immunosuppressive Drugs ◽  
Ang Ii ◽  
Hematopoietic Stem

Cyclosporin and other immunosuppressive drugs are used in bone marrow (BM) transplantation to increase engraftment efficacy and reduce rejection. However, their chronic clinical use is closely associated with increase in blood pressure and development of hypertension (HTN). Despite these significant side effects, little is known about the influence of high blood pressure on hematopoietic stem cell (HSC) and BM activity. Thus, the objective of this study was to investigate if Ang II induced HTN exerts influence on HSC proliferation, differentiation and engraftment in the BM. Infusion of Ang II (1000ng/kg/min for 21 days) and establishment of HTN resulted in increased proliferation of HSCs as evidenced by 87% increase in Sca-1+, c-Kit+, Lin- (SKL) HSC and 254% increase in CD150+, CD48- SKL long-term HSC in the BM. Furthermore, this was associated with significant accumulation of monocytes in both BM (30% increase) and spleen (250% increase). These changes in HSC and inflammatory cells were blocked by co-infusion of Ang II and losartan (60mg/kg/day), In order to understand the effect of Ang II on HSC homing, GFP+ HSCs were injected into the lethally irradiated and saline or Ang II infused C57BL6 mice. FACS analysis of GFP+ donor derived cells showed that hypertensive animals has poor engraftment efficacy on both BM and peripheral blood (35-52% compared to saline controls). Time-lapse in vivo imaging of mouse tibia showed that HSC failed to engraft to the BM osteoblastic niche in hypertensive mice. HSCs pretreated with 100nM Ang II for 18 hours in vitro also showed significantly diminished ability (16% compared to control) to engraft in normal recipient mice. These observations demonstrate that 1) chronic Ang II induced HTN regulates HSC proliferation and impairs the homing ability and reconstitution potential of HSC in BM, 2) These effects are mediated by the AT1 receptor on HSC and 3) Ang II accelerates HSC differentiation leading the increase of inflammatory cells in BM and spleen. The results suggest that hypertensive status and BP control should be strictly taken into account in consideration for BM transplantation.

scholarly journals Cushing's disease and hypertension: in vivo and in vitro study of the role of the renin-angiotensin-aldosterone system and effects of medical therapy

2014 ◽  
Vol 170 (2) ◽  
pp. 181-191 ◽  
Author(s):  
R van der Pas ◽  
J H M van Esch ◽  
C de Bruin ◽  
A H J Danser ◽  
A M Pereira ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Cushing’S Disease ◽  
In Vitro Study ◽  
Cushing's Disease ◽  
Ang Ii ◽  
Renin Angiotensin Aldosterone System ◽  
Renin Angiotensin ◽  
Raas Blockade

Objective/methodsCushing's disease (CD) is often accompanied by hypertension. CD can be treated surgically and, given the expression of somatostatin subtype 5 and dopamine 2 receptors by corticotroph pituitary adenomas, pharmacologically. Indeed, we recently observed that stepwise medical combination therapy with the somatostatin-analog pasireotide, the dopamine-agonist cabergoline, and ketoconazole (which directly suppresses steroidogenesis) biochemically controlled CD patients and lowered their blood pressure after 80 days. Glucocorticoids (GC) modulate the renin–angiotensin–aldosterone system (RAAS) among others by increasing hepatic angiotensinogen expression and stimulating mineralocorticoid receptors (MR). This study therefore evaluated plasma RAAS components in CD patients before and after drug therapy. In addition, we studied whether cabergoline/pasireotide have direct relaxant effects in angiotensin II (Ang II)-constricted iliac arteries of spontaneously hypertensive rats, with and without concomitant GR/MR stimulation with dexamethasone or hydrocortisone.ResultsBaseline concentrations of angiotensinogen were elevated, while renin and aldosterone were low and suppressed, respectively, even in patients treated with RAAS-blockers. This pattern did not change after 80 days of treatment, despite blood pressure normalization, nor after 4 years of remission. In the presence of dexamethasone, pasireotide inhibited Ang II-mediated vasoconstriction.ConclusionsThe low plasma renin concentrations, even under RAAS blockade, in CD may be the consequence of increased GC-mediated MR stimulation and/or the elevated angiotensinogen levels in such patients. The lack of change in RAAS-parameters despite blood pressure and cortisol normalization suggests persisting consequences of long-term exposure to cortisol excess. Finally, pasireotide may have a direct vasodilating effect contributing to blood pressure lowering.

scholarly journals Ghrelin Ameliorates Angiotensin II-Induced Myocardial Fibrosis by Upregulating Peroxisome Proliferator-Activated Receptor Gamma in Young Male Rats

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Qian Wang ◽  
Xin Sui ◽  
Rui Chen ◽  
Pei-Yong Ma ◽  
Yong-Liang Teng ◽  
...  
Keyword(s):  
Myocardial Fibrosis ◽  
Transforming Growth Factor ◽  
Cardiac Fibroblasts ◽  
Male Rats ◽  
Peroxisome Proliferator ◽  
Ang Ii ◽  
Sprague Dawley ◽  
Collagen Iii

Angiotensin (Ang) II contributes to the formation and development of myocardial fibrosis. Ghrelin, a gut peptide, has demonstrated beneficial effects against cardiovascular disease. In the present study, we explored the effect and related mechanism of Ghrelin on myocardial fibrosis in Ang II-infused rats. Adult Sprague-Dawley (SD) rats were divided into 6 groups: Control, Ang II (200ng/kg/min, microinfusion), Ang II+Ghrelin (100μg/kg, subcutaneously twice daily), Ang II+Ghrelin+GW9662 (a specific PPAR-γinhibitor, 1 mg/kg/d, orally), Ang II+GW9662, and Ghrelin for 4 wks. In vitro, adult rat cardiac fibroblasts (CFs) were pretreated with or without Ghrelin, Ghrelin+GW9662, or anti-Transforming growth factor (TGF)-β1 antibody and then stimulated with or without Ang II (100 nmol/L) for 24 h. Ang II infusion significantly increased myocardial fibrosis, expression of collagen I, collagen III, and TGF-β1, as well as TGF-β1 downstream proteins p-Smad2, p-Smad3, TRAF6, and p-TAK1 (all p<0.05). Ghrelin attenuated these effects. Similar results were seen in Ang II-stimulated rat cardiac fibroblasts in vitro. In addition, Ghrelin upregulated PPAR-γexpressionin vivoandin vitro, and treatment with GW9662 counteracted the effects of Ghrelin. In conclusion, Ghrelin ameliorated Ang II-induced myocardial fibrosis by upregulating PPAR-γand in turn inhibiting TGF-β1signaling.

scholarly journals Angiotensin AT2 receptor agonist prevents salt-sensitive hypertension in obese Zucker rats

2015 ◽  
Vol 308 (12) ◽  
pp. F1379-F1385 ◽  
Author(s):  
Quaisar Ali ◽  
Sanket Patel ◽  
Tahir Hussain
Keyword(s):  
Blood Pressure ◽  
Sodium Intake ◽  
Zucker Rats ◽  
Ang Ii ◽  
Maximal Increase ◽  
High Sodium ◽  
Sodium Diet ◽  
Angiotensin Type 2 Receptor ◽  
Obese Rats ◽  
Salt Sensitive Hypertension

High-sodium intake is a risk factor for the pathogenesis of hypertension, especially in obesity. The present study is designed to investigate whether angiotensin type 2 receptor (AT2R) activation with selective agonist C21 prevents high-sodium diet (HSD)-induced hypertension in obese animals. Male obese rats were treated with AT2R agonist C21 (1 mg·kg−1·day−1, oral) while maintained on either normal-sodium diet (NSD; 0.4%) or HSD (4%) for 2 wk. Radiotelemetric recording showed a time-dependent increase in systolic blood pressure in HSD-fed obese rats, being maximal increase (∼27 mmHg) at day 12 of the HSD regimen. C21 treatment completely prevented the increase in blood pressure of HSD-fed rats. Compared with NSD controls, HSD-fed obese rats had greater natriuresis/diuresis and urinary levels of nitrates, and these parameters were further increased by C21 treatment. Also, C21 treatment improved glomerular filtration rate in HSD-fed rats. HSD-fed rats expressed higher level of cortical ANG II, which was reduced to 50% by C21 treatment. HSD feeding and/or C21 treatment had no effects on cortical renin activity and the expression of angiotensin-converting enzyme (ACE) and chymase, which are ANG II-producing enzymes. However, ANG(1–7) concentration and ACE2 activity in the renal cortex were reduced by HSD feeding, and C21 treatment rescued both the parameters. Also, C21 treatment reduced the cortical expression of AT1R in HSD-fed rats, but had no effect of AT2R expression. We conclude that chronic treatment with the AT2R agonist C21 prevents salt-sensitive hypertension in obese rats, and a reduction in the renal ANG II/AT1R and enhanced ACE2/ANG(1–7) levels may play a potential role in this phenomenon.

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