Immunosuppression preserves renal autoregulatory function and microvascular P2X1 receptor reactivity in ANG II-hypertensive rats

Autoregulation is critical for protecting the kidney against arterial pressure elevation and is compromised in some forms of hypertension. Evidence indicates that activated lymphocytes contribute importantly to cardiovascular injury in hypertension. We hypothesized that activated lymphocytes contribute to renal vascular dysfunction by impairing autoregulation and P2X1 receptor signaling in ANG II-infused hypertensive rats. Male Sprague-Dawley rats receiving ANG II infusion were treated with a lymphocyte proliferation inhibitor, mycophenolate mofetil (MMF) for 2 wk. Autoregulation was assessed in vitro and in vivo using the blood-perfused juxtamedullary nephron preparation and anesthetized rats, respectively. ANG II-treated rats exhibited impaired autoregulation. At the single vessel level, pressure-mediated afferent arteriolar vasoconstriction was significantly blunted ( P < 0.05 vs. control rats). At the whole kidney level, renal blood flow passively decreased as renal perfusion pressure was reduced. MMF treatment did not alter the ANG II-induced hypertensive state; however, MMF did preserve autoregulation. The autoregulatory profiles in both in vitro or in vivo settings were similar to the responses from control rats despite persistent hypertension. Autoregulatory responses are linked to P2X1 receptor activation. Accordingly, afferent arteriolar responses to ATP and the P2X1 receptor agonist β,γ-methylene ATP were assessed. ATP- or β,γ-methylene ATP-induced vasoconstriction was significantly attenuated in ANG II-infused hypertensive rats but was normalized by MMF treatment. Moreover, MMF prevented elevation of plasma transforming growth factor-β1 concentration and lymphocyte and macrophage infiltration in ANG II-infused kidneys. These results suggest that anti-inflammatory treatment with MMF prevents lymphocyte infiltration and preserves autoregulation in ANG II-infused hypertensive rats, likely by normalizing P2X1 receptor activation.

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

BioMed Research International ◽

10.1155/2018/9897581 ◽

2018 ◽

Vol 2018 ◽

pp. 1-14 ◽

Cited By ~ 1

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.

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Pentosan polysulfate treatment preserves renal autoregulation in ANG II-infused hypertensive rats via normalization of P2X1 receptor activation

AJP Renal Physiology ◽

10.1152/ajprenal.00743.2009 ◽

2010 ◽

Vol 298 (5) ◽

pp. F1276-F1284 ◽

Cited By ~ 16

Author(s):

Zhengrong Guan ◽

Barry S. Fuller ◽

Tatsuo Yamamoto ◽

Anthony K. Cook ◽

Jennifer S. Pollock ◽

...

Keyword(s):

Renal Injury ◽

Transforming Growth Factor ◽

Smooth Muscle Actin ◽

Receptor Activation ◽

Inflammatory Factors ◽

Ang Ii ◽

Pentosan Polysulfate ◽

Hypertensive Rats ◽

Afferent Arterioles

Inflammatory factors are elevated in animal and human subjects with hypertension and renal injury. We hypothesized that inflammation contributes to hypertension-induced renal injury by impairing autoregulation and microvascular reactivity to P2X1 receptor activation. Studies were conducted in vitro using the blood-perfused juxtamedullary nephron preparation. Rats receiving ANG II (60 ng/min) infusion were treated with the anti-inflammatory agent pentosan polysulfate (PPS) for 14 days. The magnitude and progression of hypertension were similar in ANG II and ANG II+PPS-treated rats (169 ± 5 vs. 172 ± 2 mmHg). Afferent arterioles from control rats exhibited normal autoregulatory behavior with diameter decreasing from 18.4 ± 1.6 to 11.4 ± 1.7 μm when perfusion pressure was increased from 70 to 160 mmHg. In contrast, pressure-mediated vasoconstriction was markedly attenuated in ANG II-treated rats, and diameter remained essentially unchanged over the range of perfusion pressures. However, ANG II-treated rats receiving PPS exhibited normal autoregulatory behavior compared with ANG II alone rats. Arteriolar reactivity to ATP and β,γ-methylene ATP was significantly reduced in ANG II hypertensive rats compared with controls. Interestingly, PPS treatment preserved normal reactivity to P2 and P2X1 receptor agonists despite the persistent hypertension. The maximal vasoconstriction was 79 ± 3 and 81 ± 2% of the control diameter for ATP and β,γ-methylene ATP, respectively, similar to responses in control rats. PPS treatment significantly reduced α-smooth muscle actin staining in afferent arterioles and plasma transforming growth factor-β1 concentration in ANG II-treated rats. In conclusion, PPS normalizes autoregulation without altering ANG II-induced hypertension, suggesting that inflammatory processes reduce P2X1 receptor reactivity and thereby impair autoregulatory behavior in ANG II hypertensive rats.

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P2X1 receptor blockade inhibits whole kidney autoregulation of renal blood flow in vivo

AJP Renal Physiology ◽

10.1152/ajprenal.00016.2010 ◽

2010 ◽

Vol 298 (6) ◽

pp. F1360-F1368 ◽

Cited By ~ 29

Author(s):

David A. Osmond ◽

Edward W. Inscho

Keyword(s):

Blood Flow ◽

Renal Blood Flow ◽

Renal Perfusion ◽

Receptor Activation ◽

Receptor Blockade ◽

Sprague Dawley ◽

Receptor Stimulation ◽

Kidney Blood Flow

In vitro experiments demonstrate that P2X1 receptor activation is important for normal afferent arteriolar autoregulatory behavior, but direct in vivo evidence for this relationship occurring in the whole kidney is unavailable. Experiments were performed to test the hypothesis that P2X1 receptors are important for autoregulation of whole kidney blood flow. Renal blood flow (RBF) was measured in anesthetized male Sprague-Dawley rats before and during P2 receptor blockade with PPADS, P2X1 receptor blockade with IP5I, or A1 receptor blockade with DPCPX. Both P2X1 and A1 receptor stimulation with α,β-methylene ATP and CPA, respectively, caused dose-dependent decreases in RBF. Administration of either PPADS or IP5I significantly blocked P2X1 receptor stimulation. Likewise, administration of DPCPX significantly blocked A1 receptor activation to CPA. Autoregulatory behavior was assessed by measuring RBF responses to reductions in renal perfusion pressure. In vehicle-infused rats, as pressure was decreased from 120 to 100 mmHg, there was no decrease in RBF. However, in either PPADS- or IP5I-infused rats, each decrease in pressure resulted in a significant decrease in RBF, demonstrating loss of autoregulatory ability. In DPCPX-infused rats, reductions in pressure did not cause significant reductions in RBF over the pressure range of 100–120 mmHg, but the autoregulatory curve tended to be steeper than vehicle-infused rats over the range of 80–100 mmHg, suggesting that A1 receptors may influence RBF at lower pressures. These findings are consistent with in vitro data from afferent arterioles and support the hypothesis that P2X1 receptor activation is important for whole kidney autoregulation in vivo.

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AT1a influences GABAA-mediated inhibition through regulation of KCC2 expression

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00105.2018 ◽

2018 ◽

Vol 315 (5) ◽

pp. R972-R982 ◽

Cited By ~ 2

Author(s):

George E. Farmer ◽

Kirthikaa Balapattabi ◽

Martha E. Bachelor ◽

Joel T. Little ◽

J. Thomas Cunningham

Keyword(s):

Protein Expression ◽

Body Fluid ◽

Neuronal Excitability ◽

Receptor Activation ◽

Cardiovascular Control ◽

Ang Ii ◽

Sprague Dawley ◽

Fluid Homeostasis ◽

Body Fluid Homeostasis

The median preoptic nucleus (MnPO) is an integrative site involved in body fluid homeostasis, cardiovascular control, thermoregulation, and sleep homeostasis. Angiotensin II (ANG II), a neuropeptide shown to have excitatory effects on MnPO neurons, is of particular interest with regard to its role in body fluid homeostasis and cardiovascular control. The present study investigated the role of angiotensin type 1a (AT1a) receptor activation on neuronal excitability in the MnPO. Male Sprague-Dawley rats were infused with an adeno-associated virus with an shRNA against the AT1a receptor or a scrambled control. In vitro loose-patch voltage-clamp recordings of spontaneous action potential activity were made from labeled MnPO neurons in response to brief focal application of ANG II or the GABAA receptor agonist muscimol. Additionally, tissue punches from MnPO were taken to asses mRNA and protein expression. AT1a receptor knockdown neurons were insensitive to ANG II and showed a marked reduction in GABAA-mediated inhibition. The reduction in GABAA-mediated inhibition was not associated with reductions in mRNA or protein expression of GABAA β-subunits. Knockdown of the AT1a receptor was associated with a reduction in the potassium-chloride cotransporter KCC2 mRNA as well as a reduction in pS940 KCC2 protein. The impaired GABAA-mediated inhibition in AT1a knockdown neurons was recovered by bath application of phospholipase C and protein kinase C activators. The following study indicates that AT1a receptor activation mediates the excitability of MnPO neurons, in part, through the regulation of KCC2. The regulation of KCC2 influences the intracellular [Cl−] and the subsequent efficacy of GABAA-mediated currents.

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

Tropical Journal of Pharmaceutical Research ◽

10.4314/tjpr.v19i4.16 ◽

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

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

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00269.2005 ◽

2005 ◽

Vol 289 (6) ◽

pp. R1770-R1776 ◽

Cited By ~ 10

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.

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Abstract 28: Formation of Podocyte-Derived Microparticles in Diabetic Glomerular Injury

Hypertension ◽

10.1161/hyp.62.suppl_1.a28 ◽

2013 ◽

Vol 62 (suppl_1) ◽

Author(s):

Dylan Burger ◽

Jean-Francois Thibodeau ◽

Chet Holterman ◽

Kevin D Burns ◽

Christopher R Kennedy

Keyword(s):

Kidney Disease ◽

Capillary Pressure ◽

Transforming Growth Factor Beta ◽

Transforming Growth Factor ◽

Cyclic Stretch ◽

Nanoparticle Tracking Analysis ◽

Ang Ii ◽

Glomerular Injury

Hypertension is a significant cause of progressive kidney disease, particularly in the presence of diabetes. Under such conditions, increased glomerular capillary pressure subjects podocytes, specialized glomerular epithelial cells critical to filtration, to mechanical stress resulting in podocyte injury/dysfunction. Microparticles (MPs) are small (0.1-1.0 μm), membranous vesicles shed from the cell surface following injury. However, whether podocyte MP formation reflects glomerular injury is unknown. We examined MP formation by podocytes in vitro and in vivo. Conditionally immortalized human podocytes were exposed to 10% equibiaxial cyclic stretch (a mimic of increased intraglomerular pressure), high glucose (HG, 25 mM), mannitol (osmotic control), angiotensin II (Ang II, 500 nM) or transforming growth factor beta (TGF-β, 5 ng/mL). Additionally, urinary podocyte MPs were quantified in two mouse models of diabetic kidney disease: streptozotocin (STZ) and OVE26. MPs were characterized by nanoparticle tracking analysis and quantified by Annexin V (total MPs) or podocalyxin (podocyte MPs) labeling and flow cytometry. Podocyte-derived vesicles were identifiable in both media and urine samples with a mean size of 236 nm by nanoparticle tracking analysis. In vitro, cyclic stretch was associated with a 3-fold increase in MP release after 24 hours (P<0.01, n=6). HG increased MP release 5-fold after 24 hours (P<0.05, n=6). Mannitol had no effect on MP formation by either normal or stretched podocytes and neither Ang II, nor TGF-β altered podocyte MP formation over 24 hours. In vivo, both models of diabetes displayed typical hallmarks of renal injury (proteinuria, mesangial expansion). In OVE26 mice urinary podocyte MPs were elevated compared with their wild-type littermates (17479±8329 vs. 7 ±7, P<0.05, n=5-7). Similarly, STZ-treated mice displayed increased urinary podocyte MPs as compared with untreated (18035±3813 vs. 43±34, P<0.001, n=9-18) and urinary MPs levels were positively correlated with albuminuria (r2=0.74, P<0.01). Our results suggest that podocytes produce MPs which are released into urine and are indicative of glomerular injury. Such processes may be mediated by intraglomerular capillary pressure and hyperglycemia.

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Antioxidant Treatment Reverts Increased Arterial Basal Tone and Oxidative Stress in Nephrectomized (5/6) Hypertensive Rats

International Journal of Hypertension ◽

10.1155/2013/863067 ◽

2013 ◽

Vol 2013 ◽

pp. 1-8 ◽

Cited By ~ 2

Author(s):

Rodrigo O. Marañón ◽

Claudio Joo Turoni ◽

Maria Sofia Karbiner ◽

Nicolas Salas ◽

Maria Peral de Bruno

Keyword(s):

Oxidative Stress ◽

Endothelial Dysfunction ◽

Endothelial Function ◽

Vascular Dysfunction ◽

Sprague Dawley ◽

Sprague Dawley Rats ◽

Basal Tone ◽

No Bioavailability

Nonischemic 5/6 nephrectomized rat (NefR) is a model of chronic kidney disease. However, little is known about vascular dysfunction and its relation with hypertension in NefR.Aims. To evaluate possible alterations of endothelial function, NO-bioavailability, and basal tone in aorta from NefR and the role of oxidative stress. Sprague Dawley rats were divided into sham rats (SR), NefR, and NefR treated with tempol (NefR-T). Mean arterial pressure (MAP) and renal function were determined. In isolated aortic rings the following was measured: 1-endothelial function, 2-basal tone, 3-NO levels, 4-membrane potential (MP), and 5-oxidative stress. NefR increased MAP (SR: 119 ± 4 mmHg;n=7; NefR: 169 ± 6;n=8;P<0.001). Tempol did not modify MAP (NefR-T: 168 ± 10;n=6;P<0.001). NefR showed endothelial dysfunction, increased basal tone and decreased NO levels (SR: 32 ± 2 nA;n=7, NefR: 10 ± 2;n=8;P<0.001). In both in vitro and in vivo tempol improves basal tone, NO levels, and MP. Oxidative stress in NefR was reverted in NefR-T. We described, for the first time, that aorta from NefR presented increased basal tone related to endothelial dysfunction and decreased NO-bioavailability. The fact that tempol improves NO-contents and basal tone, without decrease MAP, indicates that oxidative stress could be implicated early and independently to hypertension, in the vascular alterations.

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Interaction between vasopressin and angiotensin II in vivo and in vitro: effect on aquaporins and urine concentration

AJP Renal Physiology ◽

10.1152/ajprenal.00168.2010 ◽

2010 ◽

Vol 299 (3) ◽

pp. F577-F584 ◽

Cited By ~ 24

Author(s):

Weidong Wang ◽

Chunling Li ◽

Sandra Summer ◽

Sandor Falk ◽

Robert W. Schrier

Keyword(s):

Angiotensin Ii ◽

Collecting Duct ◽

Receptor Activation ◽

Urine Concentration ◽

At1 Receptor ◽

Receptor Blockade ◽

Ang Ii ◽

Vitro Effect

The study was undertaken to examine the potential cross talk between vasopressin and angiotensin II (ANG II) intracellular signaling pathways. We investigated in vivo and in vitro whether vasopressin-induced water reabsorption could be attenuated by ANG II AT1 receptor blockade (losartan). On a low-sodium diet (0.5 meq/day) dDAVP-treated animals with or without losartan exhibited comparable renal function [creatinine clearance 1.2 ± 0.1 in dDAVP+losartan (LSDL) vs. 1.1 ± 0.1 ml·100 g−1·day−1 in dDAVP alone (LSD), P > 0.05] and renal blood flow (6.3 ± 0.5 in LSDL vs. 6.8 ± 0.5 ml/min in LSD, P > 0.05). The urine output, however, was significantly increased in LSDL (2.5 ± 0.2 vs. 1.8 ± 0.2 ml·100 g−1·day−1, P < 0.05) in association with decreased urine osmolality (2,600 ± 83 vs. 3,256 ± 110 mosmol/kgH2O, P < 0.001) compared with rats in LSD. Immunoblotting revealed significantly decreased expression of medullary AQP2 (146 ± 6 vs. 176 ± 10% in LSD, P < 0.01), p-AQP2 (177 ± 13 vs. 214 ± 12% in LSD, P < 0.05), and AQP3 (134 ± 14 vs. 177 ± 11% in LSD, P < 0.05) in LSDL compared with LSD. The expressions of AQP1, the α1- and γ-subunits of Na-K-ATPase, and the Na-K-2Cl cotransporter were not different among groups. In vitro studies showed that ANG II or dDAVP treatment was associated with increased AQP2 expression and cAMP levels, which were potentiated by cotreatment with ANG II and dDAVP and were inhibited by AT1 blockade. In conclusion, ANG II AT1 receptor blockade in dDAVP-treated rats on a low-salt diet was associated with decreased urine concentration and decreased inner medullary AQP2, p-AQP2, and AQP3 expression, suggesting that AT1 receptor activation plays a significant role in regulating aquaporin expression and modulating urine concentration in vivo. Studies in collecting duct cells were confirmatory.

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

Hypertension ◽

10.1161/hyp.36.suppl_1.690-d ◽

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.

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