scholarly journals Age-Associated Endothelial Dysfunction in Rat Mesenteric Arteries: Roles of Calcium-Activated K+ Channels (Kca)

2010 ◽  
pp. 499-508
Author(s):  
E Zhou ◽  
D Qing ◽  
J Li
Keyword(s):  
Nitric Oxide ◽  
Endothelial Dysfunction ◽  
Endothelial Function ◽  
Mesenteric Arteries ◽  
Aged Rats ◽  
Resistance Arteries ◽  
Adult Rats ◽  
Functional Changes ◽  
Kca Channels ◽  
Age Related

Age-associated changes in large blood vessels were characterized by increased arterial wall thickness, luminal dilation and impaired endothelial function. But little is known about the effect of age on structural and functional changes in small resistance arteries. The mechanisms underlying age-associated endothelial dysfunction in rat mesenteric resistance arteries were investigated in the present study. Small rat mesenteric arteries were excised and cannulated, and vascular endothelial functions were tested by acetylcholine (ACh). Our experiments showed (1) endotheliumdependent vasorelaxation induced by ACh was reduced in aged mesenteric arteries; (2) blockade of Kca channels markedly reduced the vasodilation in young and adult rats, the resultant reduction in aged rats was much smaller compared with young and adult rats; (3) inhibition of endothelial nitric oxide synthase (NOS) resulted in a significant reduction of vasodilation in young and adult, but there was a smaller reduction in aged rats. The results suggest that (1) endothelial function was impaired in mesenteric arteries of aged rats; (2) both Kca channels and nitric oxide (NO) contribute together to the ACh-induced vasorelaxation in small mesenteric arteries, and (3) both the impairment of Kca channel function and decreased NO account for the age-related endothelial dysfunction.

Abstract 55: Hiv Viral Proteins Elevate Blood Pressure And Impairs Endothelial Function In Resistance Arteries Via Sex Specific, Immune And Nox1-dependent Mechanisms In Mice.

Hypertension ◽  
2021 ◽  
Vol 78 (Suppl_1) ◽  
Author(s):  
Taylor Kress
Keyword(s):  
Blood Pressure ◽  
Endothelial Dysfunction ◽  
Endothelial Function ◽  
Viral Infection ◽  
Immune Cells ◽  
Vascular Reactivity ◽  
Radio Telemetry ◽  
Viral Proteins ◽  
Mesenteric Arteries ◽  
Resistance Arteries

Thanks to the onset of combination antiretroviral therapy (cART), patients living with HIV live longer but experience accelerated rates of hypertension. However, the etiology of HIV-associated hypertension remains ill defined, specifically the respective contributions of repressed viral infection and cART treatment. Herein, we took advantage of a transgenic model (Tg26) of repressed viral infection to investigate the contribution of HIV viral proteins to hypertension. Quantification of inflammatory cytokines revealed elevated circulating TNFα levels but also high aorta and intraperitoneal immune cells TNFα in male Tg26 mice leading to the hypothesis that HIV-associated hypertension involves immune-derived TNFα secretion and endothelial dysfunction in males and females Tg26 mice. Blood pressure (BP) was measured via radio telemetry and vascular reactivity studies performed via wire myography. BP analysis revealed increased mean arterial pressure (MAP: male: WT=112.3±1.3 vs Tg26=121.9±4.0 mmHg/ female: WT=110.6±3.01/ Tg26=120.3±6.9 mmHg) and heart rate in both sexes (P<0.05). However, blockade of TNFα action with etanercept restored BP and aortic endothelial function in male Tg26 mice only. Along with an increase in TNFα, male Tg26 aortas showed infiltration of Tcells and proinflammatory cytokines IL-18, and IL-6, which were not seen in females. However, scavenging of reactive oxygen species with the selective NOX1 inhibitor GKT771 restored aorta endothelial function in both sexes. A contributor to hypertension is impaired endothelial relaxation in resistance arteries. Mesenteric arteries showed impaired endothelial relaxation to acetylcholine in both male and female Tg26 mice (P<0.05) with no impairment in smooth muscle cell relaxation. This phenotype was reproduced in WT mice transplanted with Tg26 bone marrow (BM) and remarkably reversed in Tg26 mice receiving WT BM supporting a clear role for immune cells in endothelial dysfunction. Collectively, these data indicate that HIV-related hypertension involves immune and NOX1-dependent endothelial dysfunction in both sexes but TNFα-dependent mechanisms in males only providing evidence of sex specific mechanisms.

scholarly journals NADPH oxidase 4 has a crucial impact on the microcirculation of hypercholesteremic LDL receptor deficient mice

2021 ◽  
Vol 42 (Supplement_1) ◽  
Author(s):  
P Diaba-Nuhoho ◽  
A Shahid ◽  
C Brunssen ◽  
H Morawietz ◽  
H Brendel
Keyword(s):  
Blood Pressure ◽  
Endothelial Dysfunction ◽  
Mouse Model ◽  
Nadph Oxidase ◽  
Endothelial Function ◽  
Vascular Function ◽  
Mesenteric Arteries ◽  
Resistance Arteries ◽  
Enos Expression ◽  
Small Resistance

Abstract Introduction NADPH oxidase (NOX) 4-generated H2O2 has anti-atherosclerotic properties in conduit arteries like the aorta and carotids. However, the role of NOX4 on vascular function of small resistance arteries and blood pressure in a mouse model of familial hypercholesterolemia is unknown. Purpose We evaluated whether NOX4-generated H2O2 might play a role in perivascular adipose tissue of the thoracic aorta (tPVAT) and small resistance arteries on vascular function in a mouse model of familial hypercholesterolemia. Methods Aortic segments and mesenteric arteries from 26-week-old Ldlr−/− and Nox4−/− / Ldlr−/− mice were analysed by Mulvany myograph. In addition, vascular contraction and relaxation was analysed in the presence of L-NAME and catalase. Analysis of mRNA expression was performed in murine and human tissue by quantitative real-time PCR. Blood pressure was detected by tail cuff method in conscious, trained mice. Results Loss of NOX4 led to severe endothelial dysfunction in mesenteric arteries of Ldlr−/− mice. Blocking of NO synthases with L-NAME led to decreased endothelial relaxation in Ldlr−/− mice at the level of Nox4−/− / Ldlr−/− mice. However, incubation with L-NAME did not worsen the established endothelial dysfunction of the mesenteric arteries from Nox4−/− / Ldlr−/− mice. These results are strikingly different from the aorta, where inhibition of NO synthases led to a similarly impaired endothelial relaxation in both mouse strains. We detected a similar eNOS expression in the aorta of Ldlr−/− and Nox4−/− / Ldlr−/−, but a reduced eNOS expression in the mesenteric arteries of Nox4−/− / Ldlr−/− mice. H2O2 can induce eNOS expression. Therefore, we analysed the vascular function after catalase incubation and again found a significant reduction of endothelial function in the mesenteric arteries of Ldlr−/− mice. Finally, we analysed blood pressure of these mice and did not observe differences in systolic blood pressure, despite significant differences in endothelial function of resistant arteries. Conclusion NOX4 protects against severe endothelial dysfunction in the mesenteric artery in a model of hypercholesterolemia. FUNDunding Acknowledgement Type of funding sources: Other. Main funding source(s): Ghanaian-German postgraduate training scholarship program (DAAD)

The mechanism of resveratrol-induced vasorelaxation differs in the mesenteric resistance arteries of lean and obese rats

2000 ◽  
Vol 100 (1) ◽  
pp. 55-60 ◽  
Author(s):  
Ebrahim K. NADERALI ◽  
Sharon L. SMITH ◽  
Patrick J. DOYLE ◽  
Gareth WILLIAMS
Keyword(s):  
Methyl Ester ◽  
Endothelial Dysfunction ◽  
Endothelial Function ◽  
Mesenteric Arteries ◽  
Resistance Arteries ◽  
Rightward Shift ◽  
Endothelial Denudation ◽  
Obese Rats

Resveratrol has been shown to induce vasorelaxation. In this study, we investigated the mechanism(s) of resveratrol-induced vasorelaxation in resistance mesenteric arteries from male lean and dietary-induced obese rats. Compared with lean rats, arteries from dietary-obese rats showed significant (P < 0.001) endothelial dysfunction, as indicated by a decrease (> 20%) in maximal acetylcholine-induced vasorelaxation. Resveratrol (5–35 µmol/l) induced concentration-dependent relaxation of mesenteric arteries preconstricted with noradrenaline (8 µmol/l) or KCl (125 mmol/l) from both lean and dietary-obese rats. There were no significant differences between the two groups, achieving a maximum relaxation of > 95% at a concentration of 35 µmol/l. In noradrenaline-preconstricted arteries from lean rats, NG-nitro-L-arginine methyl ester (L-NAME; 100 and 300 µmol/l) caused a significant (P < 0.01) concentration-dependent rightward shift in reseveratrol activity, with no effect on maximal responses. However, L-NAME (100 and 300 µmol/l) did not alter the effects of reseveratrol on arteries from dietary-obese rats, giving superimposed concentration–responses curves. Indomethacin was also ineffective in altering resveratrol activity in arteries from both lean and dietary-obese rats. In noradrenaline-precontracted arteries from dietary-obese rats, responses to resveratrol were not attenuated by endothelial denudation, indicating an action independent of the endothelium. This study indicates that: (a) the maximal effects of resveratrol on resistance arteries from lean and dietary-obese rats are not effected by endothelial dysfunction, and (b) the effects of resveratrol in lean animals (where endothelial function is not impaired), but not in dietary-obese rats, are mediated via NO.

scholarly journals Endothelial dysfunction in small arteries and early signs  of atherosclerosis in ApoE knockout rats

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Simin Berenji Ardestani ◽  
Ingrid Eftedal ◽  
Michael Pedersen ◽  
Per Bendix Jeppesen ◽  
Rikke Nørregaard ◽  
...  
Keyword(s):  
Endothelial Dysfunction ◽  
Endothelial Function ◽  
Early Stage ◽  
Western Diet ◽  
Mesenteric Arteries ◽  
Standard Diet ◽  
Resistance Arteries ◽  
Small Resistance ◽  
Apoe Ko

Abstract Endothelial dysfunction is recognized as a major contributor to atherosclerosis and has been suggested to be evident far before plaque formation. Endothelial dysfunction in small resistance arteries has been suggested to initiate long before changes in conduit arteries. In this study, we address early changes in endothelial function of atherosclerosis prone rats. Male ApoE knockout (KO) rats (11- to 13-weeks-old) were subjected to either a Western or standard diet. The diet intervention continued for a period of 20–24 weeks. Endothelial function of pulmonary and mesenteric arteries was examined in vitro using an isometric myograph. We found that Western diet decreased the contribution of cyclooxygenase (COX) to control the vascular tone of both pulmonary and mesenteric arteries. These changes were associated with early stage atherosclerosis and elevated level of plasma total cholesterol, LDL and triglyceride in ApoE KO rats. Chondroid-transformed smooth muscle cells, calcifications, macrophages accumulation and foam cells were also observed in the aortic arch from ApoE KO rats fed Western diet. The ApoE KO rats are a new model to study endothelial dysfunction during the earlier stages of atherosclerosis and could help us improve preclinical drug development.

Adiponectin improves endothelial function in hyperlipidemic rats by reducing oxidative/nitrative stress and differential regulation of eNOS/iNOS activity

2007 ◽  
Vol 293 (6) ◽  
pp. E1703-E1708 ◽  
Author(s):  
Rong Li ◽  
Wen-Qing Wang ◽  
Haifeng Zhang ◽  
Xinchung Yang ◽  
Qian Fan ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Dysfunction ◽  
Endothelial Function ◽  
Vascular Dysfunction ◽  
Superoxide Production ◽  
No Production ◽  
Globular Domain ◽  
Adult Rats ◽  
Inos Activity ◽  
Nitrative Stress

Plasma adiponectin level is significantly reduced in patients with metabolic syndrome, and vascular dysfunction is an important pathological event in these patients. However, whether adiponectin may protect endothelial cells and attenuate endothelial dysfunction caused by metabolic disorders remains largely unknown. Adult rats were fed with a regular or a high-fat diet for 14 wk. The aorta was isolated, and vascular segments were incubated with vehicle or the globular domain of adiponectin (gAd; 2 μg/ml) for 4 h. The effect of gAd on endothelial function, nitric oxide (NO) and superoxide production, nitrotyrosine formation, gp91phox expression, and endothelial nitric oxide synthase (eNOS)/inducible NOS (iNOS) activity/expression was determined. Severe endothelial dysfunction (maximal vasorelaxation in response to ACh: 70.3 ± 3.3 vs. 95.2 ± 2.5% in control, P < 0.01) was observed in hyperlipidemic aortic segments, and treatment with gAd significantly improved endothelial function ( P < 0.01). Paradoxically, total NO production was significantly increased in hyperlipidemic vessels, and treatment with gAd slightly reduced, rather than increased, total NO production in these vessels. Treatment with gAd reduced (−78%, P < 0.01) superoxide production and peroxynitrite formation in hyperlipidemic vascular segments. Moreover, a moderate attenuation (−30%, P < 0.05) in gp91phox and iNOS overexpression in hyperlipidemic vessels was observed after gAd incubation. Treatment with gAd had no effect on eNOS expression but significantly increased eNOS phosphorylation ( P < 0.01). Most noticeably, treatment with gAd significantly enhanced eNOS (+83%) but reduced iNOS (−70%, P < 0.01) activity in hyperlipidemic vessels. Collectively, these results demonstrated that adiponectin protects the endothelium against hyperlipidemic injury by multiple mechanisms, including promoting eNOS activity, inhibiting iNOS activity, preserving bioactive NO, and attenuating oxidative/nitrative stress.

scholarly journals Inducible Nitric Oxide Synthase Is Involved in Endothelial Dysfunction of Mesenteric Small Arteries from Hypothyroid Rats

Endocrinology ◽  
2009 ◽  
Vol 150 (2) ◽  
pp. 1033-1042 ◽  
Author(s):  
Agostino Virdis ◽  
Rocchina Colucci ◽  
Matteo Fornai ◽  
Antonio Polini ◽  
Elena Daghini ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Dysfunction ◽  
Endothelial Function ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Oxidase Inhibitor ◽  
Mesenteric Arteries ◽  
Low Grade ◽  
Small Arteries ◽  
Male Wistar Rats ◽  
Mild Hypothyroidism

The time-dependent effects of mild hypothyroidism on endothelial function were assessed in rat mesenteric arteries. Male Wistar rats were treated with methimazole (MMI; 0.003%) or placebo up to 16 wk. Endothelial function of mesenteric small arteries was assessed by pressurized myograph. MMI-treated animals displayed a decrease in serum thyroid hormones, an increment of plasma TSH and inflammatory cytokines, and a blunted vascular relaxation to acetylcholine, as compared with controls. Endothelial dysfunction resulted from a reduced nitric oxide (NO) availability caused by oxidative excess. Vascular-inducible NO synthase (iNOS) expression was up-regulated. S-methylisothiourea (an iNOS inhibitor) normalized endothelium-dependent relaxations and restored NO availability in arteries from 8-wk MMI-animals and partly ameliorated these alterations in 16-wk MMI rats. Similar results were obtained when MMI-induced hypothyroidism was prevented by T4 replacement. Among controls, an impaired NO availability, secondary to oxidative excess, occurred at 16 wk, and it was less pronounced than in age-matched MMI animals. Both endothelial dysfunction and oxidant excess secondary to aging were prevented by apocynin (nicotinamide adenine dinucleotide phosphate oxidase inhibitor). Mesenteric superoxide production was reduced by S-methylisothiourea and T4 replacement in MMI animals and abolished by apocynin in controls (dihydroethidium staining). MMI-induced mild hypothyroidism is associated with endothelial dysfunction caused by a reduced NO availability, secondary to oxidative excess. It is suggested that in this animal model, characterized by TSH elevation and low-grade inflammation, an increased expression and function of iNOS, resulting in superoxide generation, accounts for an impaired NO availability.

Therapeutic Potential of Phosphodiesterase Inhibitors for Endothelial Dysfunction- Related Diseases

2020 ◽  
Vol 26 (30) ◽  
pp. 3633-3651 ◽  
Author(s):  
Javier Blanco-Rivero ◽  
Fabiano E. Xavier
Keyword(s):  
Nitric Oxide ◽  
Endothelial Dysfunction ◽  
Endothelial Function ◽  
Therapeutic Potential ◽  
Treatment Strategies ◽  
Phosphodiesterase Inhibitors ◽  
Developed Countries ◽  
Major Health Problem ◽  
Pde Inhibitors ◽  
Pharmaceutical Industries

Cardiovascular diseases (CVD) are considered a major health problem worldwide, being the main cause of mortality in developing and developed countries. Endothelial dysfunction, characterized by a decline in nitric oxide production and/or bioavailability, increased oxidative stress, decreased prostacyclin levels, and a reduction of endothelium-derived hyperpolarizing factor is considered an important prognostic indicator of various CVD. Changes in cyclic nucleotides production and/ or signalling, such as guanosine 3&#039;, 5&#039;-monophosphate (cGMP) and adenosine 3&#039;, 5&#039;-monophosphate (cAMP), also accompany many vascular disorders that course with altered endothelial function. Phosphodiesterases (PDE) are metallophosphohydrolases that catalyse cAMP and cGMP hydrolysis, thereby terminating the cyclic nucleotide-dependent signalling. The development of drugs that selectively block the activity of specific PDE families remains of great interest to the research, clinical and pharmaceutical industries. In the present review, we will discuss the effects of PDE inhibitors on CVD related to altered endothelial function, such as atherosclerosis, diabetes mellitus, arterial hypertension, stroke, aging and cirrhosis. Multiple evidences suggest that PDEs inhibition represents an attractive medical approach for the treatment of endothelial dysfunction-related diseases. Selective PDE inhibitors, especially PDE3 and PDE5 inhibitors are proposed to increase vascular NO levels by increasing antioxidant status or endothelial nitric oxide synthase expression and activation and to improve the morphological architecture of the endothelial surface. Thereby, selective PDE inhibitors can improve the endothelial function in various CVD, increasing the evidence that these drugs are potential treatment strategies for vascular dysfunction and reinforcing their potential role as an adjuvant in the pharmacotherapy of CVD.

Endothelial dysfunction and arterial pressure regulation during early diabetes in mice: roles for nitric oxide and endothelium-derived hyperpolarizing factor

2007 ◽  
Vol 293 (2) ◽  
pp. R707-R713 ◽  
Author(s):  
Sharyn M. Fitzgerald ◽  
Barbara K. Kemp-Harper ◽  
Helena C. Parkington ◽  
Geoffrey A. Head ◽  
Roger G. Evans
Keyword(s):  
Nitric Oxide ◽  
Endothelial Dysfunction ◽  
Arterial Pressure ◽  
Early Stage ◽  
Mesenteric Arteries ◽  
No Production ◽  
Wild Type ◽  
Early Diabetes ◽  
Diabetes In Mice ◽  
Vehicle Treatment

We determined whether nitric oxide (NO) counters the development of hypertension at the onset of diabetes in mice, whether this is dependent on endothelial NO synthase (eNOS), and whether non-NO endothelium-dependent vasodilator mechanisms are altered in diabetes in mice. Male mice were instrumented for chronic measurement of mean arterial pressure (MAP). In wild-type mice, MAP was greater after 5 wk of Nω-nitro-l-arginine methyl ester (l-NAME; 100 mg·kg−1·day−1 in drinking water; 97 ± 3 mmHg) than after vehicle treatment (88 ± 3 mmHg). MAP was also elevated in eNOS null mice (113 ± 4 mmHg). Seven days after streptozotocin treatment (200 mg/kg iv) MAP was further increased in l-NAME-treated mice (108 ± 5 mmHg) but not in vehicle-treated mice (88 ± 3 mmHg) nor eNOS null mice (104 ± 3 mmHg). In wild-type mice, maximal vasorelaxation of mesenteric arteries to acetylcholine was not altered by chronic l-NAME or induction of diabetes but was reduced by 42 ± 6% in l-NAME-treated diabetic mice. Furthermore, the relative roles of NO and endothelium-derived hyperpolarizing factor (EDHF) in acetylcholine-induced vasorelaxation were altered; the EDHF component was enhanced by l-NAME and blunted by diabetes. These data suggest that NO protects against the development of hypertension during early-stage diabetes in mice, even in the absence of eNOS. Furthermore, in mesenteric arteries, diabetes is associated with reduced EDHF function, with an apparent compensatory increase in NO function. Thus, prior inhibition of NOS results in endothelial dysfunction in early diabetes, since the diabetes-induced reduction in EDHF function cannot be compensated by increases in NO production.

scholarly journals Altered Purinergic Receptor Sensitivity in Type 2 Diabetes-Associated Endothelial Dysfunction and Up4A-Mediated Vascular Contraction

2018 ◽  
Vol 19 (12) ◽  
pp. 3942 ◽  
Author(s):  
Ali Mahdi ◽  
Tong Jiao ◽  
Yahor Tratsiakovich ◽  
Jiangning Yang ◽  
Claes-Göran Östenson ◽  
...  
Keyword(s):  
Endothelial Dysfunction ◽  
Endothelial Function ◽  
Vascular Function ◽  
Purinergic Receptor ◽  
Purinergic Signaling ◽  
Mesenteric Arteries ◽  
Vascular Contraction ◽  
Gk Rats ◽  
Vasoconstrictor Response

Purinergic signaling may be altered in diabetes accounting for endothelial dysfunction. Uridine adenosine tetraphosphate (Up4A), a novel dinucleotide substance, regulates vascular function via both purinergic P1 and P2 receptors (PR). Up4A enhances vascular contraction in isolated arteries of diabetic rats likely through P2R. However, the precise involvement of PRs in endothelial dysfunction and the vasoconstrictor response to Up4A in diabetes has not been fully elucidated. We tested whether inhibition of PRs improved endothelial function and attenuated Up4A-mediated vascular contraction using both aortas and mesenteric arteries of type 2 diabetic (T2D) Goto Kakizaki (GK) rats vs. control Wistar (WT) rats. Endothelium-dependent (EDR) but not endothelium-independent relaxation was significantly impaired in both aortas and mesenteric arteries from GK vs. WT rats. Non-selective inhibition of P1R or P2R significantly improved EDR in aortas but not mesenteric arteries from GK rats. Inhibition of A1R, P2X7R, or P2Y6R significantly improved EDR in aortas. Vasoconstrictor response to Up4A was enhanced in aortas but not mesenteric arteries of GK vs. WT rats via involvement of A1R and P2X7R but not P2Y6R. Depletion of major endothelial component nitric oxide enhanced Up4A-induced aortic contraction to a similar extent between WT and GK rats. No significant differences in protein levels of A1R, P2X7R, and P2Y6R in aortas from GK and WT rats were observed. These data suggest that altered PR sensitivity accounts for endothelial dysfunction in aortas in diabetes. Modulating PRs may represent a potential therapy for improving endothelial function.

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