scholarly journals Hyperphosphatemia-Induced Oxidant/Antioxidant Imbalance Impairs Vascular Relaxation and Induces Inflammation and Fibrosis in Old Mice

Antioxidants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1308
Author(s):  
Ana Asenjo-Bueno ◽  
Elena Alcalde-Estévez ◽  
Mariam El Assar ◽  
Gemma Olmos ◽  
Patricia Plaza ◽  
...  

Aging impairs vascular function, but the mechanisms involved are unknown. The aim of this study was to analyze whether aging-related hyperphosphatemia is implied in this effect by elucidating the role of oxidative stress. C57BL6 mice that were aged 5 months (young) and 24 months (old), receiving a standard (0.6%) or low-phosphate (0.2%) diet, were used. Isolated mesenteric arteries from old mice showed diminished endothelium-dependent vascular relaxation by the down-regulation of NOS3 expression, increased inflammation and increased fibrosis in isolated aortas, compared to those isolated from young mice. In parallel, increased Nox4 expression and reduced Nrf2, Sod2-Mn and Gpx1 were found in the aortas from old mice, resulting in oxidant/antioxidant imbalance. The low-phosphate diet improved vascular function and oxidant/antioxidant balance in old mice. Mechanisms were analyzed in endothelial (EC) and vascular smooth muscle cells (SMCs) treated with the phosphate donor ß-glycerophosphate (BGP). In EC, BGP increased Nox4 expression and ROS production, which reduced NOS3 expression via NFκB. BGP also increased inflammation in EC. In SMC, BGP increased Collagen I and fibronectin expression by priming ROS production and NFκB activity. In conclusion, hyperphosphatemia reduced endothelium-dependent vascular relaxation and increased inflammation and vascular fibrosis through an impairment of oxidant/antioxidant balance in old mice. A low-phosphate diet achieved improvements in the vascular function in old mice.

2021 ◽  
Vol 22 (3) ◽  
pp. 1296
Author(s):  
Yue Ruan ◽  
Subao Jiang ◽  
Adrian Gericke

Age-related macular degeneration (AMD) is a common irreversible ocular disease characterized by vision impairment among older people. Many risk factors are related to AMD and interact with each other in its pathogenesis. Notably, oxidative stress and choroidal vascular dysfunction were suggested to be critically involved in AMD pathogenesis. In this review, we give an overview on the factors contributing to the pathophysiology of this multifactorial disease and discuss the role of reactive oxygen species and vascular function in more detail. Moreover, we give an overview on therapeutic strategies for patients suffering from AMD.


2016 ◽  
Vol 76 (2) ◽  
pp. 500-505
Author(s):  
F. A. Moraga ◽  
N. Urriola-Urriola

Abstract Previous studies performed in intertidal fish (Girella laevifrons),as well as marine fish (Isacia conceptionis), showed that acetylcholine (ACh) produced contractions mediated by cyclooxygenases that were dependent on the area and potency of contraction in several arterial vessels. Given that the role of nitric oxide is poorly understood in fish, the objective of our study was to evaluate the role of nitric oxide in branchial afferent (ABA), branchial efferent (ABE), dorsal (DA) and mesenteric (MA) arterial vessels from both Girella laevifrons and Isacia conceptionis. We studied afferent and efferent branchial, dorsal and mesenteric arteries that were dissected from 6 juvenile specimens. Isometric tension studies were done using dose response curves (DRC) for Ach (10–13 to 10–3 M) and blockade with L-NAME (10–5 M), and DRC for sodium nitroprusside (SNP, a donor of NO). L-NAME produced an attenuation of the contractile response in the dorsal, afferent and efferent branchial arteries and a potentiation of the contraction in the MA. SNP caused 70% dilation in the mesenteric artery and 40% in the dorsal artery. Our results suggest that Ach promotes precarious dilatation in MA mediated by NO; data that is supported by the use of sodium nitroprusside. In contrast, in the vessels DA, ABA and EBA our results support that the pathway Ach-NO-relaxation is absent in both species.


2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Takayuki Matsumoto ◽  
Rita C. Tostes ◽  
R. Clinton Webb

The endothelium plays a pivotal role in vascular homeostasis, and endothelial dysfunction is a major feature of cardiovascular diseases, such as arterial hypertension, atherosclerosis, and diabetes. Recently, uridine adenosine tetraphosphate (Up4A) has been identified as a novel and potent endothelium-derived contracting factor (EDCF). Up4A structurally contains both purine and pyrimidine moieties, which activate purinergic receptors. There is an accumulating body of evidence to show that Up4A modulates vascular function by actions on endothelial and smooth muscle cells. In this paper, we discuss the effects of Up4A on vascular function and a potential role for Up4A in cardiovascular diseases.


2014 ◽  
Vol 42 (4) ◽  
pp. 1006-1011 ◽  
Author(s):  
Mark R. Miller

Air pollution has been estimated to be responsible for several millions of deaths worldwide per year, the majority of which have been attributed to cardiovascular causes. The particulate matter in air pollution has been shown impair vascular function, increase blood pressure, promote thrombosis and impair fibrinolysis, accelerate the development of atherosclerosis, increase the extent of myocardial ischaemia, and increase susceptibility to myocardial infarction. The pathways underlying these effects are complex and poorly understood; however, particulate-induced oxidative stress repeatedly emerges as a potential mechanism in all of these detrimental cardiovascular actions. The present mini-review will use diesel exhaust as an example of a pollutant rich in combustion-derived nanoparticles, to describe the potential by which oxidative stress could drive the cardiovascular effects of air pollution.


2007 ◽  
Vol 27 (01) ◽  
pp. 5-12 ◽  
Author(s):  
G. Muller ◽  
C. Goettsch ◽  
H. Morawietz

SummaryThis review focuses on the role of vascular oxidative stress in the development and progression of endothelial dysfunction. We discuss different sources of oxidative stress in the vessel wall, oxidative stress and coagulation, the role of oxidative stress and vascular function in arteries and veins, the flow-dependent regulation of reactive oxygen species, the putative impact of oxidative stress on atherosclerosis, the interaction of angiotensin II, oxidative stress and endothelial dysfunction, and clinical implications.


2004 ◽  
Vol 287 (1) ◽  
pp. H40-H45 ◽  
Author(s):  
Sukrutha Veerareddy ◽  
Christy-Lynn M. Cooke ◽  
Philip N. Baker ◽  
Sandra T. Davidge

Oxidative stress mediated by prooxidants has been implicated in the pathogenesis of vascular disorders. However, the effect of prooxidants on myogenic regulation of vascular function and the differential influence of gender is not known. SOD, an intracellular enzyme, restricts excess prooxidant levels and may limit vascular dysfunction. We therefore tested the effects of Cu,Zn SOD deficiency on vascular tone in both male and female SOD knockout (SOD−/−) mice. We hypothesized that myogenic tone would be enhanced in SOD−/− mice by excess prooxidants compared with wild-type control mice. Indeed, resistance-sized mesenteric arteries from SOD−/− mice exhibited enhanced myogenic tone compared with control mice. Myogenic tone was lower in female than male control mice. Interestingly, this gender effect was absent in SOD−/− mice, such that myogenic tone of mesenteric arteries from females was equated to that of arteries from males. Furthermore, the pathways that modulate myogenic tone were diverse. In both male and female control mice, inhibition of prostaglandin H synthase (PGHS) and nitric oxide synthase (NOS) pathways enhanced myogenic tone. In female SOD−/− mice, inhibition of PGHS and NOS pathways enhanced myogenic tone to a greater extent compared with control mice. Conversely, in male SOD−/− mice, NOS and PGHS inhibition did not alter tone and only inhibition of gap junctions enhanced myogenic tone. In conclusion, this study revealed enhanced myogenic tone in SOD−/− mice compared with control mice. Furthermore, Cu,Zn SOD deficiency particularly enhanced myogenic tone in female mice such that their vascular tone attained the level of male SOD−/− mice, possibly mediated by prooxidants.


2005 ◽  
Vol 83 (1) ◽  
pp. 63-68 ◽  
Author(s):  
Lingyun Wu

Methylglyoxal (MG), a highly reactive metabolite of glucose, causes non-enzymatic glycation of proteins to form irreversible advanced glycation endproducts (AGEs). The present study investigated whether methylglyoxal induced oxidative stress and activated nuclear factor kappa B (NF-κB) in freshly isolated and cultured smooth muscle cells (SMCs) from rat mesenteric artery. The treatment of cells with MG (50 or 100 µmol/L) induced a significant increase in AGE formation and oxidation of DCF. MG-enhanced generation of AGEs and the oxidation of DCF was markedly inhibited by antioxidant n-acetylcysteine (NAC, 600 µmol/L). MG at a concentration of 100 µmol/L increased the heme-oxygenase-1 expression in these cells. Moreover, MG activated NF-κB p65, indicated by an increased im muno cytochemistry stain for NF-κB p65 located in the nucleus after the treatment of mesenteric artery SMCs with MG. MG-induced activation of NF-κB p65 was inhibited by NAC. In summary, MG significantly increases oxidative stress and activates NF-κB p65 in mesenteric artery SMCs. The pro-oxidant role of methylglyoxal may contribute to various pathological changes of SMCs from resistance arteries.Key words: methylglyoxal, oxidative stress, NF-κB p65, vascular smooth muscle cells, mesenteric artery.


2005 ◽  
Vol 288 (1) ◽  
pp. H7-H12 ◽  
Author(s):  
Karine Laude ◽  
Hua Cai ◽  
Bruno Fink ◽  
Nyssa Hoch ◽  
David S. Weber ◽  
...  

Protein levels and polymorphisms of p22 phox have been suggested to modulate vascular NAD(P)H oxidase activity and vascular production of reactive oxygen species (ROS). We sought to determine whether increasing p22 phox expression would alter vascular ROS production and hemodynamics by targeting p22 phox expression to smooth muscle in transgenic (Tg) mice. Aortas of Tg p22smc mice had increased p22 phox and Nox1 protein levels and produced more superoxide and H2O2. Surprisingly, endothelium-dependent relaxation and blood pressure in Tg p22smc mice were normal. Aortas of Tg p22smc mice produced twofold more nitric oxide (NO) at baseline and sevenfold more NO in response to calcium ionophore as detected by electron spin resonance. Western blot analysis revealed a twofold increase in endothelial NO synthase (eNOS) protein expression in Tg p22smc mice. Both eNOS expression and NO production were normalized by infusion of the glutathione peroxidase mimetic ebselen or by crossing Tg p22smc mice with mice overexpressing catalase. We have previously found that NO stimulates extracellular superoxide dismutase (ecSOD) expression in vascular smooth muscle. In keeping with this, aortic segments from Tg p22smc mice expressed twofold more ecSOD, and chronic treatment with the NOS inhibitor NG-nitro-l-arginine methyl ester normalized this, suggesting that NO regulates ecSOD protein expression in vivo. These data indicate that chronic oxidative stress caused by excessive H2O2 production evokes a compensatory response involving increased eNOS expression and NO production. NO in turn increases ecSOD protein expression and counterbalances increased ROS production leading to the maintenance of normal vascular function and hemodynamics.


2014 ◽  
Vol 307 (4) ◽  
pp. H563-H573 ◽  
Author(s):  
John J. Reho ◽  
Xiaoxu Zheng ◽  
James E. Benjamin ◽  
Steven A. Fisher

There is evidence for developmental origins of vascular dysfunction yet little understanding of maturation of vascular smooth muscle (VSM) of regional circulations. We measured maturational changes in expression of myosin phosphatase (MP) and the broader VSM gene program in relation to mesenteric small resistance artery (SRA) function. We then tested the role of the sympathetic nervous system (SNS) in programming of SRAs and used genetically engineered mice to define the role of MP isoforms in the functional maturation of the mesenteric circulation. Maturation of rat mesenteric SRAs as measured by qPCR and immunoblotting begins after the second postnatal week and is not complete until maturity. It is characterized by induction of markers of VSM differentiation (smMHC, γ-, α-actin), CPI-17, an inhibitory subunit of MP and a key target of α-adrenergic vasoconstriction, α1-adrenergic, purinergic X1, and neuropeptide Y1 receptors of sympathetic signaling. Functional correlates include maturational increases in α-adrenergic-mediated force and calcium sensitization of force production (MP inhibition) measured in first-order mesenteric arteries ex vivo. The MP regulatory subunit Mypt1 E24+/LZ- isoform is specifically upregulated in SRAs during maturation. Conditional deletion of mouse Mypt1 E24 demonstrates that splicing of E24 causes the maturational reduction in sensitivity to cGMP-mediated vasorelaxation (MP activation). Neonatal chemical sympathectomy (6-hydroxydopamine) suppresses maturation of SRAs with minimal effect on a conduit artery. Mechanical denervation of the mature rat renal artery causes a reversion to the immature gene program. We conclude that the SNS captures control of the mesenteric circulation by programming maturation of the SRA smooth muscle.


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