scholarly journals Vascular Dysfunction as Target Organ Damage in Animal Models of Hypertension

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Mario Fritsch Neves ◽  
Daniel Arthur B. Kasal ◽  
Ana Rosa Cunha ◽  
Fernanda Medeiros
Keyword(s):  
Endothelial Dysfunction ◽  
Vascular Reactivity ◽  
Vascular Dysfunction ◽  
Target Organ Damage ◽  
Organ Damage ◽  
Experimental Hypertension ◽  
Chronic Hypertension ◽  
No Production ◽  
Response Curves ◽  
Spontaneously Hypertensive

Endothelial dysfunction is one of the main characteristics of chronic hypertension and it is characterized by impaired nitric oxide (NO) bioactivity determined by increased levels of reactive oxygen species. Endothelial function is usually evaluated by measuring the vasodilation induced by the local NO production stimulated by external mechanical or pharmacological agent. These vascular reactivity tests may be carried out in different models of experimental hypertension such as NO-deficient rats, spontaneously hypertensive rats, salt-sensitive rats, and many others. Wire myograph and pressurized myograph are the principal methods used for vascular studies. Usually, increasing concentrations of the vasodilator acetylcholine are added in cumulative manner to perform endothelium-dependent concentration-response curves. Analysis of vascular mechanics is relevant to identify arterial stiffness. Both endothelial dysfunction and vascular stiffness have been shown to be associated with increased cardiovascular risk.

Mesenteric arteries from stroke-prone spontaneously hypertensive rats exhibit an increase in nitric-oxide-dependent vasorelaxation

2018 ◽  
Vol 96 (8) ◽  
pp. 719-727 ◽  
Author(s):  
Brandi M. Wynne ◽  
Hicham Labazi ◽  
Victor V. Lima ◽  
Fernando S. Carneiro ◽  
R. Clinton Webb ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Dysfunction ◽  
Vascular Reactivity ◽  
Spontaneously Hypertensive Rat ◽  
No Synthase ◽  
Mesenteric Arteries ◽  
Maximum Effect ◽  
No Production ◽  
Primary Role ◽  
Spontaneously Hypertensive

The endothelium is crucial for the maintenance of vascular tone by releasing several vasoactive substances, including nitric oxide (NO). Systemic mean arterial pressure is primarily regulated by the resistance vasculature, which has been shown to exhibit increased vascular reactivity, and decreased vasorelaxation during hypertension. Here, we aimed to determine the mechanism for mesenteric artery vasorelaxation of the stroke-prone spontaneously hypertensive rat (SHRSP). We hypothesized that endothelial NO synthase (eNOS) is upregulated in SHRSP vessels, increasing NO production to compensate for the endothelial dysfunction. Concentration–response curves to acetylcholine (ACh) were performed in second-order mesenteric arteries; we observed decreased relaxation responses to ACh (maximum effect elicited by the agonist) as compared with Wistar-Kyoto (WKY) controls. Vessels from SHRSP incubated with Nω-nitro-l-arginine methyl ester and (or) indomethacin exhibited decreased ACh-mediated relaxation, suggesting a primary role for NO-dependent relaxation. Vessels from SHRSP exhibited a significantly decreased relaxation response with inducible NO synthase (iNOS) inhibition, as compared with WKY vessels. Western blot analysis showed increased total phosphorylated NF-κB, and phosphorylated and total eNOS in SHRSP vessels. Overall, these data suggest a compensatory role for NO by increased eNOS activation. Moreover, we believe that iNOS, although increasing NO bioavailability to compensate for decreased relaxation, leads to a cycle of further endothelial dysfunction in SHRSP mesenteric arteries.

scholarly journals Aging Additively Influences Insulin- and Insulin-Like Growth Factor-1-Mediated Endothelial Dysfunction and Antioxidant Deficiency in Spontaneously Hypertensive Rats

Biomedicines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 676
Author(s):  
Kunanya Masodsai ◽  
Yi-Yuan Lin ◽  
Sih-Yin Lin ◽  
Chia-Ting Su ◽  
Shin-Da Lee ◽  
...  
Keyword(s):  
Growth Factor ◽  
Endothelial Dysfunction ◽  
Spontaneously Hypertensive Rats ◽  
No Production ◽  
Organ Bath ◽  
Insulin Like Growth Factor ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Nos Inhibitors ◽  
Wistar Kyoto

This study aimed to investigate the aging-related endothelial dysfunction mediated by insulin and insulin-like growth factor-1 (IGF-1) and antioxidant deficiency in hypertension. Male spontaneously hypertensive rats (SHRs) and age-matched normotensive Wistar–Kyoto rats (WKYs) were randomly divided into 24-week-old (younger) and 48-week-old (older) groups, respectively. The endothelial function was evaluated by the insulin- and IGF-1-mediated vasorelaxation of aortic rings via the organ bath system. Serum levels of nitric oxide (NO), malondialdehyde (MDA), catalase, and total antioxidant capacity (TAC) were examined. The insulin- and IGF-1-mediated vasorelaxation was significantly impaired in both 24- and 48-week-old SHRs compared with age-matched WKYs and was significantly worse in the 48-week-old SHR than the 24-week-old SHR. After pretreatments of phosphoinositide 3-kinase (PI3K) or NO synthase (NOS) inhibitors, the insulin- and IGF-1-mediated vasorelaxation became similar among four groups. The serum level of MDA was significantly increased, while the NO, catalase, and TAC were significantly reduced in the 48-week-old SHR compared with the 24-week-old SHR. This study demonstrated that the process of aging additively affected insulin- and IGF-1-mediated endothelial dysfunction in SHRs, which could be partly attributed to the reduced NO production and antioxidant deficiency.

Differential expression of α2D-adrenoceptor and eNOS in aortas from early and later stages of diabetes in Goto-Kakizaki rats

2004 ◽  
Vol 287 (1) ◽  
pp. H135-H148 ◽  
Author(s):  
Tsuneo Kobayashi ◽  
Takayuki Matsumoto ◽  
Kazuyuki Ooishi ◽  
Katsuo Kamata
Keyword(s):  
Vascular Reactivity ◽  
Matched Control ◽  
Early Stage ◽  
Vascular Dysfunction ◽  
Spontaneous Diabetes ◽  
Relaxation Response ◽  
No Production ◽  
Gk Rats ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

The aim of the present study was to compare vascular dysfunction between the early (12 wk old) and later (36 wk old) stages of spontaneous diabetes in Goto-Kakizaki (GK) rats. We also evaluated the aortic expression of the α2D-adrenoceptor and endothelial nitric oxide synthase (eNOS). Vascular reactivity was assessed in thoracic aortas from age-matched control rats and 12- and 36-wk GK rats. Using RT-PCR and immunoblots, we also examined the changes in expression of the α2D-adrenoceptor and eNOS. In aortas from GK rats (vs. those from age-matched control rats): 1) the relaxation response to ACh was enhanced at 12 wk but decreased at 36 wk; 2) the relaxation response to sodium nitroprusside was decreased at both 12 and 36 wk, 3) norepinephrine (NE)-induced contractility was decreased at 12 wk but not at 36 wk, 4) the expressions of α1B- and α1D-adrenoceptors were unaffected, whereas those of α2D-adrenoceptor and eNOS mRNAs were increased at both 12 and 36 wk; and 5) NE- and ACh-stimulated NOx (nitrite and nitrate) levels were increased at 12 wk, although at 36 wk ACh-stimulated NOx was lower, whereas NE-stimulated NOx showed no change. These results clearly demonstrate that enhanced ACh-induced relaxation and impaired NE-induced contraction, due to NO overproduction via eNOS and increased α2D-adrenoceptor expression, occur in early-stage GK rats and that the impaired ACh-induced relaxation in later-stage GK rats is due to reductions in both NO production and NO responsiveness (but not in eNOS expression).

Abstract 343: Vascular Inflammation in Two Rat Models of Arterial Hypertension is Promoted by Coagulation FXI

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Jeremy Lagrange ◽  
Sabine Kossmann ◽  
Andreas Daiber ◽  
Matthias Oelze ◽  
Brett Monia ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Arterial Hypertension ◽  
Feedback Loop ◽  
Thrombin Generation ◽  
Vascular Reactivity ◽  
Platelet Rich Plasma ◽  
Vascular Dysfunction ◽  
Vascular Inflammation ◽  
Critical Role ◽  
Experimental Hypertension

Backgroud: Interactions of platelets, leukocytes and the vessel wall play pivotal roles in activating coagulation and precipitating thrombosis. We were recently able to uncover an angiotensin II (ATII) driven factor XI (FXI)-thrombin amplification loop leading to vascular injury in experimental hypertension in mice. Objective: We wanted was to explore the role of thrombin-FXI feedback loop in different models of arterial hypertension in rats. Methods: ATII treated wistar rats (1mg·kg -1 ·d -1 for 7 days using osmotic minipumps) and 5/6 nephrectomized were used for this study. During 2 weeks rats were treated with a FXI antisense oligonucleotide (ASO) (1 week after nephrectomy or 2 weeks before ATII pump implantation, respectively). Blood pressure was recorded with tail cuff measurement. Fluorescence oxidative microtopography was used to evaluate vascular ROS production. Vascular reactivity was assessed in isolated aortic segment. Calibrated automated thrombography was used to measure thrombin generation. Results: In ATII infused rats as well as 5/6 nephrectomized rats vascular dysfunction related to hypertension was attenuated when rats were treated with FXI ASO. Hypertension induced VCAM-1 expression was normalize with inhibition of FXI. ROS formation was normalized in ATII infused rats as well as 5/6 nephrectomized treated with FXI ASO. Thrombin generation in platelet rich plasma from 5/6 nephrectomized rats was completely abolished when FXI was inhibited. Finally the overall blood pressure increase was abrogated by FXI ASO treatment in 5/6 nephrectomized rats. Conclusion: FXI plays a critical role in a FXI-thrombin feedback loop in hypertension. This pathway is relevant in mice and rats and we were able to very recently obtain the first conclusive results in humans. FXI could be a novel therapeutic target to interrupt this heterotypic cellular coagulation-inflammatory circuit.

Evidence That Reduced Renal Medullary NOS Activity of Dahl S Rats Enables Small Elevations of Avp to Produce Sustained Hypertension

Hypertension ◽  
2000 ◽  
Vol 36 (suppl_1) ◽  
pp. 682-682
Author(s):  
Baozhi Yuan ◽  
Allen W Cowley
Keyword(s):  
Nitric Oxide ◽  
Control Level ◽  
Renal Medulla ◽  
Renal Tissue ◽  
Brown Norway ◽  
Experimental Hypertension ◽  
Chronic Hypertension ◽  
No Production ◽  
Potent Vasoconstrictor ◽  
Plasma Arginine

27 It remains unclear why sustained elevations of plasma arginine vasopressin (AVP), a potent vasoconstrictor and fluid retaining hormone, do not generally result in hypertension. Related to this, there have been 4 general observations: 1) AVP is elevated in many forms of human and experimental hypertension, including Dahl S rats; 2) AVP can stimulate nitric oxide synthases (NOS) and nitric oxide (NO) production in the renal medulla of normal rats; 3) AVP stimulated NO production can buffer AVP induced reductions of medullary blood flow; 4) partial reduction of medullary NOS activity (via medullary L-NAME infusion) unmasks chronic hypertensive effects of small elevations of plasma AVP (Hypertension. 2000; 35:740-745). In the present study, we hypothesize that Dahl salt-sensitive rats (DS) have reduced capacity to synthesize medullary NO which sensitizes them to the hypertensive effects of small elevations of circulating AVP. DS and Brown Norway (BN) rats with implanted arterial and venous catheters were fed a 0.4% salt diet and infused continuously for 14 days with a chronic “subpressor” dose of AVP (2 ng/kg/min). Conscious mean arterial pressure (MAP) was measured 2 hours daily with rats maintained in their home cages. MAP in DS rats increased during day1 of AVP infusion from a control level of 127 ± 0.9 mmHg to an average of 147 ± 1.6 mmHg after 14 days. MAP did not return to control values even within three days following the end of AVP infusion. BN rats showed no changes of MAP during 14 days of AVP infusion (90.4 ± 0.6 mmHg and 92.3 ± 0.4 mmHg). Northern blot analysis of renal tissue from vehicle (saline) infused rats demonstrated that NOS I and NOS III mRNA expression was significantly less in DS rats in the renal outer medulla compared to BN rats. We conclude that small, normally subpressor elevations of plasma AVP can produce chronic hypertension in DS rats, a phenomenon probably related to reduced renal medullary NO synthesis.

scholarly journals VE-PTP inhibition elicits eNOS phosphorylation to blunt endothelial dysfunction and hypertension in diabetes

2020 ◽  
Author(s):  
Mauro Siragusa ◽  
Alberto Fernando Oliveira Justo ◽  
Pedro Felipe Malacarne ◽  
Anna Strano ◽  
Akshay Buch ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Endothelial Cells ◽  
Shear Stress ◽  
Endothelial Dysfunction ◽  
Vascular Reactivity ◽  
Therapeutic Option ◽  
Diabetic Patients ◽  
No Production ◽  
Vascular Endothelial ◽  
Enos Activity

Abstract Aims Receptor-type vascular endothelial protein tyrosine phosphatase (VE-PTP) dephosphorylates Tie-2 as well as CD31, VE-cadherin, and vascular endothelial growth factor receptor 2 (VEGFR2). The latter form a signal transduction complex that mediates the endothelial cell response to shear stress, including the activation of the endothelial nitric oxide (NO) synthase (eNOS). As VE-PTP expression is increased in diabetes, we investigated the consequences of VE-PTP inhibition (using AKB-9778) on blood pressure in diabetic patients and the role of VE-PTP in the regulation of eNOS activity and vascular reactivity. Methods and results In diabetic patients AKB-9778 significantly lowered systolic and diastolic blood pressure. This could be linked to elevated NO production, as AKB increased NO generation by cultured endothelial cells and elicited the NOS inhibitor-sensitive relaxation of endothelium-intact rings of mouse aorta. At the molecular level, VE-PTP inhibition increased the phosphorylation of eNOS on Tyr81 and Ser1177 (human sequence). The PIEZO1 activator Yoda1, which was used to mimic the response to shear stress, also increased eNOS Tyr81 phosphorylation, an effect that was enhanced by VE-PTP inhibition. Two kinases, i.e. abelson-tyrosine protein kinase (ABL)1 and Src were identified as eNOS Tyr81 kinases as their inhibition and down-regulation significantly reduced the basal and Yoda1-induced tyrosine phosphorylation and activity of eNOS. VE-PTP, on the other hand, formed a complex with eNOS in endothelial cells and directly dephosphorylated eNOS Tyr81 in vitro. Finally, phosphorylation of eNOS on Tyr80 (murine sequence) was found to be reduced in diabetic mice and diabetes-induced endothelial dysfunction (isolated aortic rings) was blunted by VE-PTP inhibition. Conclusions VE-PTP inhibition enhances eNOS activity to improve endothelial function and decrease blood pressure indirectly, through the activation of Tie-2 and the CD31/VE-cadherin/VEGFR2 complex, and directly by dephosphorylating eNOS Tyr81. VE-PTP inhibition, therefore, represents an attractive novel therapeutic option for diabetes-induced endothelial dysfunction and hypertension.

Vasodilation mediated by human PTH 1-34 in the spontaneously hypertensive rat

1984 ◽  
Vol 246 (1) ◽  
pp. F96-F100 ◽  
Author(s):  
D. A. McCarron ◽  
D. H. Ellison ◽  
S. Anderson
Keyword(s):  
Spontaneously Hypertensive Rat ◽  
Ionized Calcium ◽  
Experimental Hypertension ◽  
Base Line ◽  
Response Curves ◽  
Hypotensive Action ◽  
Spontaneously Hypertensive ◽  
Hypertensive Rat ◽  
Serum Ionized Calcium ◽  
Wistar Kyoto

Parathyroid hormone's cardiovascular effects were assessed in a model of experimental hypertension with known abnormalities of calcium metabolism. Mean arterial pressure (MAP) changes and serum ionized calcium responses were measured in the spontaneously hypertensive rat (SHR) and its normotensive control, the Wistar-Kyoto (WKY), following injections of synthetic human PTH 1-34. Six 22-wk-old SHR and six WKY were given intra-arterial serial injections (0.1-100 micrograms/kg) of hPTH 1-34. Both the SHR (P less than 0.001) and WKY (P less than 0.001) demonstrated log dose-dependent hypotensive responses that were maximal at 1 min, with recovery occurring between 15 and 30 min. The slopes, however, of the dose-response curves differed (P less than 0.01). The SHR experienced a greater maximal delta MAP [-93.7 +/- 2.4 (SHR) vs. -71.2 +/- 1.6 mmHg (WKY), P less than 0.01]. Furthermore, the duration of the hypotensive action of hPTH 1-34 was significantly longer (P less than 0.001) in the SHR. Even when corrected for base-line MAP the SHR demonstrated a significant (P = 0.025) enhancement of this vasodilator response at doses of 5 micrograms/kg and greater at time intervals between 3 and 9 min after injection. A transient decrease [2.25 +/- 0.10 (pre) vs. 2.17 +/- 0.11 meq/liter (1 min post), P less than 0.01] in serum ionized calcium occurred at 1 min. We conclude that hPTH 1-34 is a potent vasoactive peptide in both the normotensive WKY and the SHR. The greater maximal hypotensive response to hPTH 1-34 and the prolongation of this cardiovascular effect in the SHR may be an additional manifestation of this experimental animal's acknowledged abnormalities of cellular membrane calcium and phospholipid metabolism.

p38 MAPK Inhibitors Ameliorate Target Organ Damage in Hypertension: Part 1. p38 MAPK-Dependent Endothelial Dysfunction and Hypertension

2003 ◽  
Vol 307 (3) ◽  
pp. 932-938 ◽  
Author(s):  
Haisong Ju ◽  
David J. Behm ◽  
Sandyha Nerurkar ◽  
Marianne E. Eybye ◽  
Robin E. Haimbach ◽  
...  
Keyword(s):  
Endothelial Dysfunction ◽  
P38 Mapk ◽  
Target Organ Damage ◽  
Organ Damage ◽  
Target Organ ◽  
P38 Mapk Inhibitors ◽  
Mapk Inhibitors
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