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 ◽  
...  

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.

Hypertension ◽  
2021 ◽  
Vol 78 (Suppl_1) ◽  
Author(s):  
Daniel J Fehrenbach ◽  
Meena S Madhur

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.


2020 ◽  
Vol 19 (4) ◽  
pp. 789-796
Author(s):  
Moon Jain ◽  
Hina Iqbal ◽  
Pankaj Yadav ◽  
Himalaya Singh ◽  
Debabrata Chanda ◽  
...  

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


Hypertension ◽  
2014 ◽  
Vol 64 (suppl_1) ◽  
Author(s):  
Seungbum Kim ◽  
Christopher R Cogle ◽  
Michael Zingler ◽  
Edward W Scott ◽  
Mohan K Raizada

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.


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 ◽  
...  

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.


Hypertension ◽  
2000 ◽  
Vol 36 (suppl_1) ◽  
pp. 690-690
Author(s):  
Michael J Katovich ◽  
Hongwei Wang ◽  
Stephan Gallinat ◽  
Colin Sumners ◽  
Mohan K Raizada

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.


2021 ◽  
Vol 12 ◽  
Author(s):  
Xiaoli Du ◽  
Qianqian Tao ◽  
Hongxia Du ◽  
Zhenbang Zhao ◽  
Yu Dong ◽  
...  

BACKGROUND: Hypertension-induced renal damage is a serious and complex condition that has not been effectively treated by conventional blood pressure-lowering drugs. Tengdan capsule (TDC) is a China FDA-approved compound herbal medicine for treating hypertension; however, its chemical basis and pharmacological efficacy have not been fully investigated in a preclinical setting.METHODS: High-performance liquid chromatography (HPLC) was used to identify and quantify the major chemical components of TDC extracted from ultrapure water. Adult spontaneously hypertensive rats (SHR) and age/sex-matched Wistar Kyoto normotensive rats (WKY) were both treated with TDC, losartan, or saline for one month, and their blood pressure (BP) was monitored at the same time by tail-cuff BP system. Biochemical indexes such as urine creatinine (CRE) and blood urea nitrogen (BUN) were determined. Kidney tissue sections were examined with (H&amp;E), and Masson staining to evaluate the pathological effect of TDC on SHR’s kidneys. After TDC treatment, the differentially expressed proteins in the kidneys of SHR were identified by the TMT-based quantitative proteomics analysis, which may provide the targets and possible mechanisms of TDC action. In addition, Western blot analysis, RT-qPCR, and ELISA assays were carried out to further verify the proteomics findings. Finally, two different models involving in vitro renal injuries were established using human kidney HEK293 cells; and the molecular mechanism of TDC kidney protection was demonstrated.RESULTS: Seven chemical compounds, namely Notoginsenoside R1, Ginsenoside RG1, Ginsenoside Re, Ginsenoside Rb1, Sodium Danshensu, Protocatechualdehyde, and Salvianolic acid B, were identified and quantified from the water-soluble extracts of TDC by HPLC. In vivo study using rats showed that TDC effectively reduced BP, BUN, and CRE levels and attenuated renal fibrosis in SHR, and ameliorated damage to the kidneys. Proteomics and subsequent bioinformatics analyses indicated that periostin-mediated inflammatory response and TGFβ/Smad signaling pathway proteins were closely related to the therapeutic effect of TDC in rat kidneys. Western blot analysis and RT-qPCR showed that TDC markedly downregulated the mRNA and protein expression of periostin in renal tissues compared to the untreated SHR. In addition, TGF-β and COL1A1 mRNA levels also decreased in SHR renal tissues following TDC treatment. In vitro studies showed that low to medium doses of TDC down-regulated the expression of periostin in the injury model of HEK293 cell. In addition, medium to high doses of TDC significantly inhibited collagen deposition in TGFβ1-induced HEK293 cell fibrosis.CONCLUSIONS: Major components from the compound herbal medicine Tengdan Capsule are identified and quantified. TDC effectively lowers blood pressure and protects against renal damage caused by hypertension in SHR. Mechanistically, TDC blocks periostin by regulating the TGF-β/Smad signaling pathway in the kidney, both in vivo and in vitro. Preventing periostin-mediated renal fibrosis and inflammation might be a promising strategy for treating a hypertensive renal injury.


2007 ◽  
Vol 293 (3) ◽  
pp. H1745-H1749 ◽  
Author(s):  
Erika I. Boesen ◽  
David M. Pollock

Interleukin (IL)-6 has been implicated as a contributing factor in the pathogenesis of hypertension, although the mechanisms involved are unclear. Studies conducted in vitro suggest that IL-6 may have a direct effect on vascular tone and may modulate constrictor responses to agonists. Whether this effect can be observed in vivo is unknown. Therefore, mice were treated with either IL-6 (16 ng/h sc) or vehicle for 14 days, and the acute blood pressure and heart rate responses to endothelin (ET)-1, angiotensin II (ANG II), and phenylephrine (PE) were assessed under isoflurane anesthesia. Blood pressure responses to ET-1 were identical in vehicle- and IL-6-infused mice, both in the presence and the absence of ganglion blockade with chlorisondamine. The fall in heart rate during ET-1 responses was significantly attenuated in IL-6-infused mice with autonomic reflexes intact (vehicle vs. IL-6, P < 0.05 at 1 and 3 nmol/kg of ET-1), but this difference was not observed after ganglionic blockade. Both blood pressure and heart rate responses to ANG II were indistinguishable between IL-6- and vehicle-infused mice, as were responses to PE except for a significant increase in the blood pressure response and decrease in the heart rate response in IL-6-infused mice observed only at the highest dose of PE (300 μg/kg; P < 0.05). These findings show that, despite what might be predicted from studies conducted in vitro, chronic exposure to elevated plasma IL-6 concentrations in itself does not predispose the mouse to enhanced responsiveness to vasoconstrictors in vivo.


1974 ◽  
Vol 31 (03) ◽  
pp. 420-428 ◽  
Author(s):  
M Fainaru ◽  
S Eisenberg ◽  
N Manny ◽  
C Hershko

SummaryThe natural course of defibrination syndrome caused by Echis colorata venom (ECV) in five patients is reported. All patients developed afibrinogenemia within six hours after the bite. Concomitantly a depression in factor V was recorded. Factor VIII and thrombocyte count in blood were normal in most patients. In the light of the known effects of ECV on blood coagulation in vivo and in vitro it is concluded that the afibrinogenemia is due to intravascular clotting.Four patients had transient renal damage, manifested by oliguria, azotemia, albuminuria and cylindruria, ascribed to microthrombi in the renal glomeruli.After the bite, the natural course was benign, no major bleeding was observed, and all signs of coagulopathy reverted to normal within 7 days. Therefore we recommend no specific treatment for this condition. In the case of heavily bleeding patients, administration of antiserum against ECV and/or heparin should be considered.


2020 ◽  
Vol 20 (8) ◽  
pp. 1253-1261
Author(s):  
Mourad Akdad ◽  
Mohamed Eddouks

Aims: The present study was performed in order to analyze the antihypertensive activity of Micromeria graeca (L.) Benth. ex Rchb. Background: Micromeria graeca (L.) Benth. ex Rchb is an aromatic and medicinal plant belonging to the Lamiaceae family. This herb is used to treat various pathologies such as cardiovascular disorders. Meanwhile, its pharmacological effects on the cardiovascular system have not been studied. Objective: The present study aimed to evaluate the effect of aqueous extract of aerial parts of Micromeria graeca (AEMG) on the cardiovascular system in normotensive and hypertensive rats. Methods: In this study, the cardiovascular effect of AEMG was evaluated using in vivo and in vitro investigations. In order to assess the acute effect of AEMG on the cardiovascular system, anesthetized L-NAME-hypertensive and normotensive rats received AEMG (100 mg/kg) orally and arterial blood pressure parameters were monitored during six hours. In the sub-chronic study, rats were orally treated for one week, followed by blood pressure assessment during one week of treatment. Blood pressure was measured using a tail-cuff and a computer-assisted monitoring device. In the second experiment, isolated rat aortic ring pre-contracted with Epinephrine (EP) or KCl was used to assess the vasorelaxant effect of AEMG. Results: Oral administration of AEMG (100 mg/kg) provoked a decrease of arterial blood pressure parameters in hypertensive rats. In addition, AEMG induced a vasorelaxant effect in thoracic aortic rings pre-contracted with EP (10 μM) or KCl (80 mM). This effect was attenuated in the presence of propranolol and methylene blue. While in the presence of glibenclamide, L-NAME, nifedipine or Indomethacin, the vasorelaxant effect was not affected. Conclusion: This study showed that Micromeria graeca possesses a potent antihypertensive effect and relaxes the vascular smooth muscle through β-adrenergic and cGMP pathways.


Author(s):  
Mohammed Ajebli ◽  
Mohamed Eddouks

Aims and objective: The aim of the study was to investigate the effect of aqueous aerial part extract of Mentha pulegium L. (Pennyrile) (MPAE) on arterial pressure parameters in rats. Background: Mentha pulegium is a medicinal plant used to treat hypertension in Morocco. Material and methods: In the current study, MPAE was prepared and its antihypertensive activity was pharmacologically investigated. L-NAME-hypertensive and normotensive rats have received orally MPAE (180 and 300 mg/kg) during six hours for the acute experiment and during seven days for the sub-chronic treatment. Thereafter, systolic, diastolic, mean arterial blood pressure and heart rate were evaluated. While, in the in vitro experiment, isolated denuded and intact thoracic aortic rings were suspended in a tissue bath system and the tension changes were recorded. Results: A fall in blood pressure was observed in L-NAME-induced hypertensive treated with MPAE. The extract also produced a dose-dependent relaxation of aorta pre-contracted with NE and KCl. The study showed that the vasorelaxant ability of MPAE seems to be exerted through the blockage of extracellular Ca2+ entry. Conclusion: The results demonstrate that the extract of pennyrile exhibits antihypertensive activity. In addition, the effect may be, at least in part, due to dilation of blood vessels via blockage of Ca2+ channels.


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