Endothelial Dysfunction in Diabetes – Clasic Sources of Vascular Oxidative Stress (Nadph Oxidases, Enos Uncoupling and Xanthine Oxidase)

Abstract Cardiovascular disease is the leading cause of disease / mortality worldwide. It is generally accepted that increased production of reactive oxygen species (ROS) has an important role in cardiovascular pathology, contributing to endothelial dysfunction and to the aggravation of atherosclerosis. Among all cardiovascular risk factors, diabetes mellitus is one of the most important. The worldwide prevalence of diabetes has increased rapidly even in developing countries, doubling the combined risk of cardiovascular events in patients with hypertension. In diabetes, increased reactive oxygen species (ROS) production leads to endothelial dysfunction, recognized by the presence of impaired vascular relaxation, increased vascular smooth muscle cells growth and hypertrophy, all together contributing to atherosclerotic plaque formation. On this basis, the vascular endothelium has emerged as a therapeutic target, with the aim to improve systemic metabolic state by improving vascular function. In this review we have focused on the most important sources of reactive oxygen species generated by vascular endothelium in diabetic patients (NADPH Oxidases, eNOS uncoupling, Xanthine oxidase). The importance of oxidative stress in mediating the vascular complications of diabetes is supported by studies showing that antioxidant therapy correct the vascular function in humans or in experimental models of diabetes. Therefore, understanding the physiological mechanisms involved in vascular disorders resulting from hyperglycemia is essential for the proper use of available therapeutic resources.

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Clinical aspects of reactive oxygen and nitrogen species

Biochemical Society Symposium ◽

10.1042/bss0710121 ◽

2004 ◽

Vol 71 ◽

pp. 121-133 ◽

Cited By ~ 25

Author(s):

Ascan Warnholtz ◽

Maria Wendt ◽

Michael August ◽

Thomas Münzel

Keyword(s):

Oxidative Stress ◽

Reactive Oxygen Species ◽

Risk Factor ◽

Endothelial Dysfunction ◽

Vascular Tissue ◽

Rapid Development ◽

Reactive Oxygen ◽

Clinical Aspects ◽

No Production ◽

Oxygen Species

Endothelial dysfunction in the setting of cardiovascular risk factors, such as hypercholesterolaemia, hypertension, diabetes mellitus and chronic smoking, as well as in the setting of heart failure, has been shown to be at least partly dependent on the production of reactive oxygen species in endothelial and/or smooth muscle cells and the adventitia, and the subsequent decrease in vascular bioavailability of NO. Superoxide-producing enzymes involved in increased oxidative stress within vascular tissue include NAD(P)H-oxidase, xanthine oxidase and endothelial nitric oxide synthase in an uncoupled state. Recent studies indicate that endothelial dysfunction of peripheral and coronary resistance and conductance vessels represents a strong and independent risk factor for future cardiovascular events. Ways to reduce endothelial dysfunction include risk-factor modification and treatment with substances that have been shown to reduce oxidative stress and, simultaneously, to stimulate endothelial NO production, such as inhibitors of angiotensin-converting enzyme or the statins. In contrast, in conditions where increased production of reactive oxygen species, such as superoxide, in vascular tissue is established, treatment with NO, e.g. via administration of nitroglycerin, results in a rapid development of endothelial dysfunction, which may worsen the prognosis in patients with established coronary artery disease.

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Role of TNF-α-induced reactive oxygen species in endothelial dysfunction during reperfusion injury

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00587.2008 ◽

2008 ◽

Vol 295 (6) ◽

pp. H2242-H2249 ◽

Cited By ~ 55

Author(s):

Xue Gao ◽

Hanrui Zhang ◽

Souad Belmadani ◽

Junxi Wu ◽

Xiangbin Xu ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Endothelial Dysfunction ◽

Myocardial Ischemia ◽

Endothelial Function ◽

Xanthine Oxidase ◽

Reactive Oxygen ◽

Neutrophil Activation ◽

Superoxide Production ◽

Oxygen Species ◽

Tnf Α

We hypothesized that neutralization of TNF-α at the time of reperfusion exerts a salubrious role on endothelial function and reduces the production of reactive oxygen species. We employed a mouse model of myocardial ischemia-reperfusion (I/R, 30 min/90 min) and administered TNF-α neutralizing antibodies at the time of reperfusion. I/R elevated TNF-α expression (mRNA and protein), whereas administration of anti-TNF-α before reperfusion attenuated TNF-α expression. We detected TNF-α expression in vascular smooth muscle cells, mast cells, and macrophages, but not in the endothelial cells. I/R induced endothelial dysfunction and superoxide production. Administration of anti-TNF-α at the onset of reperfusion partially restored nitric oxide-mediated coronary arteriolar dilation and reduced superoxide production. I/R increased the activity of NAD(P)H oxidase and of xanthine oxidase and enhanced the formation of nitrotyrosine residues in untreated mice compared with shams. Administration of anti-TNF-α before reperfusion blocked the increase in activity of these enzymes. Inhibition of xanthine oxidase (allopurinol) or NAD(P)H oxidase (apocynin) improved endothelium-dependent dilation and reduced superoxide production in isolated coronary arterioles following I/R. Interestingly, I/R enhanced superoxide generation and reduced endothelial function in neutropenic animals and in mice treated with a neutrophil NAD(P)H oxidase inhibitor, indicating that the effects of TNF-α are not through neutrophil activation. We conclude that myocardial ischemia initiates TNF-α expression, which induces vascular oxidative stress, independent of neutrophil activation, and leads to coronary endothelial dysfunction.

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Reactive oxygen species cause endothelial dysfunction in chronic flow overload

Journal of Applied Physiology ◽

10.1152/japplphysiol.00786.2009 ◽

2011 ◽

Vol 110 (2) ◽

pp. 520-527 ◽

Cited By ~ 17

Author(s):

X. Lu ◽

X. Guo ◽

C. D. Wassall ◽

M. D. Kemple ◽

J. L. Unthank ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Shear Stress ◽

Endothelial Dysfunction ◽

Nadph Oxidase ◽

Group Treatment ◽

Carotid Arteries ◽

Reactive Oxygen ◽

Ros Production ◽

Oxygen Species ◽

Enos Uncoupling

Although elevation of shear stress increases production of vascular reactive oxygen species (ROS), the role of ROS in chronic flow overload (CFO) has not been well investigated. We hypothesize that CFO increases ROS production mediated in part by NADPH oxidase, which leads to endothelial dysfunction. In six swine, CFO in carotid arteries was induced by contralateral ligation for 1 wk. In an additional group, six swine received apocynin (NADPH oxidase blocker and anti-oxidant) treatment in conjunction with CFO for 1 wk. The blood flow in carotid arteries increased from 189.2 ± 25.3 ml/min (control) to 369.6 ± 61.9 ml/min (CFO), and the arterial diameter increased by 8.6%. The expressions of endothelial nitric oxide synthase (eNOS), p22/p47phox, and NOX2/NOX4 were upregulated. ROS production increased threefold in response to CFO. The endothelium-dependent vasorelaxation was compromised in the CFO group. Treatment with apocynin significantly reduced ROS production in the vessel wall, preserved endothelial function, and inhibited expressions of p22/p47phox and NOX2/NOX4. Although the process of CFO remodeling to restore the wall shear stress has been thought of as a physiological response, the present data implicate NADPH oxidase-produced ROS and eNOS uncoupling in endothelial dysfunction at 1 wk of CFO.

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Apocynin and Tempol ameliorate dietary sodium-induced declines in cutaneous microvascular function in salt-resistant humans

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00786.2018 ◽

2019 ◽

Vol 317 (1) ◽

pp. H97-H103 ◽

Cited By ~ 10

Author(s):

Meghan G. Ramick ◽

Michael S. Brian ◽

Evan L. Matthews ◽

Jordan C. Patik ◽

Douglas R. Seals ◽

...

Keyword(s):

Oxidative Stress ◽

Reactive Oxygen Species ◽

Vascular Function ◽

Reactive Oxygen ◽

Microvascular Function ◽

High Salt ◽

Dietary Sodium ◽

Oxygen Species ◽

High Sodium ◽

Cutaneous Vasodilation

It has previously been shown that high dietary salt impairs vascular function independent of changes in blood pressure. Rodent studies suggest that NADPH-derived reactive oxygen species mediate the deleterious effect of high salt on the vasculature, and here we translate these findings to humans. Twenty-nine healthy adults (34 ± 2 yr) participated in a controlled feeding study. Participants completed 7 days of a low-sodium diet (LS; 20 mmol sodium/day) and 7 days of a high-sodium diet (HS; 300 mmol sodium/day) in random order. All participants were salt resistant, defined as a ≤5-mmHg change in 24-h mean BP determined while on the LS and HS diets. Laser Doppler flowmetry was used to assess cutaneous vasodilation in response to local heating (42°C) during local delivery of Ringer’s ( n = 29), 20 mM ascorbic acid (AA; n = 29), 10 µM Tempol ( n = 22), and 100 µM apocynin ( n = 22). Additionally, endothelial cells were obtained in a subset of participants from an antecubital vein and stained for nitrotyrosine ( n = 14). Cutaneous vasodilation was attenuated by the HS diet compared with LS [LS 93.0 ± 2.2 vs. HS 86.8 ± 2.0 percentage of maximal cutaneous vascular conductance (%CVCmax); P < 0.05] and was restored by AA during the HS diet (AA 90.7 ± 1.2 %CVCmax; P < 0.05 vs. HS). Cutaneous vasodilation was also restored with the local infusion of both apocynin ( P < 0.01) and Tempol ( P < 0.05) on the HS diet. Nitrotyrosine expression was increased on the HS diet compared with LS ( P < 0.05). These findings provide direct evidence of dietary sodium-induced endothelial cell oxidative stress and suggest that NADPH-derived reactive oxygen species contribute to sodium-induced declines in microvascular function. NEW & NOTEWORTHY High-sodium diets have deleterious effects on vascular function, likely mediating, in part, the increased cardiovascular risk associated with a high sodium intake. Local infusion of apocynin and Tempol improved microvascular function in salt-resistant adults on a high-salt diet, providing evidence that reactive oxygen species contribute to impairments in microvascular function from high salt. This study provides insight into the blood pressure-independent mechanisms by which dietary sodium impairs vascular function. Listen to this article’s corresponding podcast at https://ajpheart.podbean.com/e/dietary-sodium-oxidative-stress-and-microvascular-function/ .

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The effect of ethanol on the development of oxidative stress and endothelial dysfunction

Medical Science And Education Of Ural ◽

10.36361/1814-8999-2020-21-3-143-149 ◽

2020 ◽

Vol 21 (3) ◽

pp. 143-149

Author(s):

I. A. Chernov ◽

◽

Yu. A. Kirillov ◽

D. A. Areshidze ◽

M. A. Kozlova ◽

...

Keyword(s):

Oxidative Stress ◽

Reactive Oxygen Species ◽

Endothelial Dysfunction ◽

Structural Changes ◽

Alcohol Intoxication ◽

Reactive Oxygen ◽

The Body ◽

Oxygen Species ◽

Electron Microscopic ◽

Small Doses

The review focuses on the pathogenetic mechanisms of ethanol influence on the development of oxidative stress (OS) and endothelial dysfunction (ED). It is shown that both in acute and chronic alcohol intoxication, the intake of ethanol in the body initiates the development of OS, the formation of reactive oxygen species, causes a decrease in the content of endothelium-derived relaxing factors (nitric oxide (NO), prostacyclin, endothelium-derived hyperpolarization factor (EDHF)), an increase in the concentration of endothelium-derived constricting factors (endothelin, angiotensin-II), thereby causing the development of ED. When alcohol is consumed in small doses by healthy non-drinkers, ethanol can act as an antioxidant, cause the neutralization of reactive oxygen species, promote the formation of NO, and prevent the formation of ED. Currently used methods for evaluating ED allow us to characterize the functional state of the endothelium. Structural changes in the blood vessel wall as a manifestation of ED in alcoholic disease are not sufficiently described, which indicates the need to study them using modern histological, histochemical, immunohistochemical and electron microscopic methods.

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Role of xanthine oxidase in the formation and release of reactive oxygen species from cultured vascular endothelium

Free Radical Biology and Medicine ◽

10.1016/0891-5849(90)90522-k ◽

1990 ◽

Vol 9 ◽

pp. 98 ◽

Cited By ~ 1

Author(s):

Andrés Paler-Martinez ◽

Peter Panus ◽

Bruce Freeman

Keyword(s):

Reactive Oxygen Species ◽

Xanthine Oxidase ◽

Vascular Endothelium ◽

Reactive Oxygen ◽

Oxygen Species

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Increased Oxidative Stress and Xanthine Oxidase Activity in Human Ruptured Cerebral Aneurysms

The Neuroradiology Journal ◽

10.1177/197140090702000512 ◽

2007 ◽

Vol 20 (5) ◽

pp. 545-550 ◽

Cited By ~ 2

Author(s):

Li Li ◽

Xinjian Yang ◽

Gregory J Dusting ◽

Zhongxue Wu ◽

Fan Jiang

Keyword(s):

Oxidative Stress ◽

Reactive Oxygen Species ◽

Xanthine Oxidase ◽

Oxidase Activity ◽

Superficial Temporal Artery ◽

Cerebral Aneurysms ◽

Reactive Oxygen ◽

Aortic Aneurysms ◽

Oxygen Species ◽

Xanthine Oxidase Activity

Recent studies have suggested that oxidative stress may be involved in the development of arterial aneurysms. Xanthine oxidase is implicated in the generation of reactive oxygen species under pathological conditions in the cardiovascular system, and increased xanthine oxidase activity has been reported in human aortic aneurysms. We, therefore, studied the changes of xanthine oxidase activity and oxidative stress in human ruptured cerebral aneurysms. Six cerebral aneurysmal samples were obtained during surgery. Normal arteries of the similar size (one superficial temporal artery, four uterine arteries and three right gastroepiploic arteries) were used as controls. The xanthine oxidase activity was measured with a commercial assay kit, and its expression was localized by immunohistochemistry. The xanthine oxidase activity was significantly increased in aneurysms by 4.1 fold (P<0.05) compared to control arteries. This was accompanied by an elevated malondialdehyde (MDA) level (8.3±5.1 versus 2.9±0.7 nmol/g protein, mean ±SD, P<0.05), a marker of oxidative stress. Immunohistochemistry established that xanthine oxidase was mainly expressed in infiltrating inflammatory cells. Our study indicates that xanthine oxidase may have an important role in the increased oxidative stress in ruptured cerebral aneurysms. Further studies are needed to clarify the role of XO-derived reactive oxygen species in the development and rupture of cerebral aneurysms.

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Glycosylation with O-linked β-N-acetylglucosamine induces vascular dysfunction via production of superoxide anion/reactive oxygen species

Canadian Journal of Physiology and Pharmacology ◽

10.1139/cjpp-2017-0225 ◽

2018 ◽

Vol 96 (3) ◽

pp. 232-240

Author(s):

Leonardo Souza-Silva ◽

Rheure Alves-Lopes ◽

Jéssica Silva Miguez ◽

Vanessa Dela Justina ◽

Karla Bianca Neves ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Endothelial Dysfunction ◽

Nadph Oxidase ◽

Protein Expression ◽

Vascular Function ◽

Superoxide Anion ◽

Vascular System ◽

Reactive Oxygen ◽

Oxygen Species ◽

Endothelium Dependent Relaxation

Overproduction of superoxide anion (•O2−) and O-linked β-N-acetylglucosamine (O-GlcNAc) modification in the vascular system are contributors to endothelial dysfunction. This study tested the hypothesis that increased levels of O-GlcNAc-modified proteins contribute to •O2− production via activation of NADPH oxidase, resulting in impaired vasodilation. Rat aortic segments and vascular smooth muscle cells (VSMCs) were incubated with vehicle (methanol) or O-(2-acetamido-2-deoxy-d-glucopyranosylidenamino) N-phenylcarbamate (PUGNAc) (100 μM). PUGNAc produced a time-dependent increase in O-GlcNAc levels in VSMC and decreased endothelium-dependent relaxation, which was prevented by apocynin and tiron, suggesting that •O2− contributes to endothelial dysfunction under augmented O-GlcNAc levels. Aortic segments incubated with PUGNAc also exhibited increased levels of reactive oxygen species, assessed by dihydroethidium fluorescence, and augmented •O2− production, determined by lucigenin-enhanced chemiluminescence. Additionally, PUGNAc treatment increased Nox-1 and Nox-4 protein expression in aortas and VSMCs. Translocation of the p47phox subunit from the cytosol to the membrane was greater in aortas incubated with PUGNAc. VSMCs displayed increased p22phox protein expression after PUGNAc incubation, suggesting that NADPH oxidase is activated in conditions where O-GlcNAc protein levels are increased. In conclusion, O-GlcNAc levels reduce endothelium-dependent relaxation by overproduction of •O2− via activation of NADPH oxidase. This may represent an additional mechanism by which augmented O-GlcNAc levels impair vascular function.

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