scholarly journals A Standardized Lindera obtusiloba Extract Improves Endothelial Dysfunction and Attenuates Plaque Development in Hyperlipidemic ApoE-Knockout Mice

Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2493
Author(s):  
Sang-Hyun Ihm ◽  
Sin-Hee Park ◽  
Jung-Ok Lee ◽  
Ok-Ran Kim ◽  
Eun-Hye Park ◽  
...  

Lindera obtusiloba extract (LOE), a traditional herbal medicine used to enhance blood circulation and to reduce inflammation, induced NO-mediated endothelium-dependent relaxation, and reduced the formation of reactive oxygen species (ROS). The study investigated whether LOE improves endothelial dysfunction and reduces plaque inflammation and progression by inhibiting ROS generation in a mouse model of atherosclerosis. Eight-week-old apolipoprotein E-deficient (apoE−/−) mice fed with a western diet (WD) were randomized into different groups by administering vehicle (0.5% carboxymethylcellulose (CMC)), LOE (100 mg/kg/day), or losartan (30 mg/kg/day) by gavage until the age of 28 weeks. Fourteen male C57BL/6 mice that were fed normal chow and treated with CMC were used as negative controls. Similar to losartan treatment, LOE treatment induced the concentration-dependent relaxation of aorta rings in WD-fed apoE−/− mice. LOE treatment significantly reduced the vascular ROS formation and expression of NADPH oxidase subunits, including p22phox and p47phox. Compared with WD-fed apoE−/− mice, mice exposed to chronic LOE treatment exhibited reductions in plaque inflammation-related fluorescence signals and atherosclerotic lesions. These effects were greater than those of losartan treatment. In conclusion, LOE treatment improves endothelial dysfunction and reduces plaque inflammation as well as lesion areas by reducing vascular NADPH oxidase-induced ROS generation in a mouse model of atherosclerosis.

2010 ◽  
Vol 108 (6) ◽  
pp. 1745-1756 ◽  
Author(s):  
Hsiu-Chung Ou ◽  
Tuzz-Ying Song ◽  
Yueh-Chiao Yeh ◽  
Chih-Yang Huang ◽  
Shun-Fa Yang ◽  
...  

Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), originally identified as the major receptor for oxidized low-density lipoprotein (oxLDL) in endothelial cells, plays a major role in the pathology of vascular diseases. Green tea consumption is associated with reduced cardiovascular mortality in some epidemiological studies. In the present study, we hypothesized that the most abundant polyphenolic compound in tea, epigallocatechin-3-gallate (EGCG), can downregulate parameters of endothelial dysfunction by modulating LOX-1-regulated cell signaling. In cultured human umbilical vein endothelial cells (HUVECs), exposure to oxLDL (130 μg/ml), which led to an increase in LOX-1 expression at the RNA and protein levels, was abrogated by addition of EGCG or DPI, a well-known inhibitor of flavoproteins, suggesting the involvement of NADPH oxidase. Furthermore, oxLDL rapidly activated the membrane translocation of Rac-1 and p47phox and the subsequent induction of ROS generation, which was suppressed markedly by pretreatment with EGCG or anti-LOX-1 monoclonal antibody. OxLDL also increased p38 MAPK phosphorylation and decreased phosphorylation of the amino-terminal region of Akt, with maximal induction at about 30 min, and NF-κB phosphorylation within 1 h, resulting in redox-sensitive signaling. In addition, oxLDL diminished the expression of endothelial nitric oxide synthase (eNOS), enhanced the expression of endothelin-1 and adhesion molecules (ICAM, E-selectin, and monocyte chemoattractant protein-1), and increased the adherence of monocytic THP-1 cells to HUVECs. Pretreatment with EGCG, however, exerted significant cytoprotective effects in all events. These data suggest that EGCG inhibits the oxLDL-induced LOX-1-mediated signaling pathway, at least in part, by inhibiting NADPH oxidase and consequent ROS-enhanced LOX-1 expression, which contributes to further ROS generation and the subsequent activation of NF-κB via the p38 MAPK pathway. Results from this study may provide insight into a possible molecular mechanism by which EGCG suppresses oxLDL-mediated vascular endothelial dysfunction.


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 4639-4639
Author(s):  
Meifang Wu ◽  
Suman Kundu ◽  
Keith R. McCrae

Abstract Introduction: Antiphospholipid syndrome (APS) is characterized by thrombosis and/or recurrent fetal loss in the presence of persistently elevated antiphospholipid antibodies (APLA). The majority of pathologic APLA are directed against β2-glycoprotein I (β2GPI). APLA cause endothelial dysfunction, though the underlying mechanisms have not been clearly delineated. Methods: Endothelial cells (EC) were incubated with β2GPI and either control antibodies or anti-β2GPI antibodies affinity-purified from sera of patients with APS, in the absence or presence of diapocynin, an NADPH oxidase (NOX) inhibitor, or siRNA against NOX1, NOX2, or NOX4. Generation of reactive oxygen species (ROS) in EC and conditioned medium were measured using fluorescent dyes (CM-H2DCFDA and CellROX Deep Red) or chemiluminescent substrate. NOX1, NOX2, NOX4, 3-nitrotyrosine, and thioredoxin reductase 1 (TrxR1) expression were analyzed by western blot. eNOS monomer and dimer were detected using cold (4°C) SDS-PAGE and immunoblot. Immunoprecipitation of TrxR1 was performed using protein A/G agarose. EC activation was assessed by measuring expression of E-selectin. Results: Incubation of EC with β2GPI and anti-β2GPI antibodies stimulated ROS generation in EC, as well as the release of ROS into conditioned medium. Expression of NOX2, but not NOX1 or NOX4, was significantly increased in EC exposed to anti-β2GPI antibodies, but not control IgG. Preteatment of endothelial cells with diapocynin, a NOX inhibitor, or siRNA against NOX2 and NOX4, but not NOX1, inhibited endothelial cell activation by anti-β2GPI antibodies. Furthermore, anti-β2GPI antibody-treated EC generated more peroxynitrite, as determined by 3-nitrotyrosine expression. Treatment of EC with anti-β2GPI antibodies increased eNOS monomer/dimer ratio, suggesting eNOS uncoupling. Compared to control human IgG, the TrxR1 immunoprecipitate from EC treated with β2GPI and anti-β2GPI antibodies contained more 3-nitrotyrosine level, suggesting TrxR1 tyrosine residue modification by nitration and possible loss of function. Conclusions: β2GPI and anti-β2GPI antibodies stimulate ROS generation in EC, with release into the conditioned medium. The impairment of EC activation by diapocynin, NOX2 siRNA, or NOX4 siRNA suggests that NOX mediate EC activation by anti-β2GPI antibodies. Anti-β2GPI antibodies induce nitrative stress in EC, which might be explained by eNOS uncoupling induced by these antibodies. The nitration of TrxR1, an enzyme that prevents eNOS uncoupling, may result in the inactivation of TrxR1 and contribute to eNOS uncoupling. Taken together, these studies provide preliminary evidence of the contribution of NOX activation and eNOS uncoupling in mediating oxidative and nitrative stress and induction of EC dysfunction by APLA. Disclosures McCrae: Janssen: Membership on an entity's Board of Directors or advisory committees; Syntimmune: Consultancy; Momenta: Consultancy; Halozyme: Membership on an entity's Board of Directors or advisory committees.


2009 ◽  
Vol 296 (3) ◽  
pp. H840-H846 ◽  
Author(s):  
Ping Zhang ◽  
Mingxiao Hou ◽  
Yunfang Li ◽  
Xin Xu ◽  
Michel Barsoum ◽  
...  

Increased reactive oxygen species (ROS) produced by the failing heart can react with nitric oxide (NO), thereby decreasing NO bioavailability. This study tested the hypothesis that increased ROS generation contributes to coronary endothelial dysfunction in the failing heart. Congestive heart failure (CHF) was produced in six dogs by ventricular pacing at 240 beats/min for 4 wk. Studies were performed at rest and during treadmill exercise under control conditions and after treatment with the NADPH oxidase inhibitor and antioxidant apocynin (4 mg/kg iv). Apocynin caused no significant changes in heart rate, aortic pressure, left ventricular (LV) systolic pressure, LV end-diastolic pressure, or maximum rate of LV pressure increase at rest or during exercise in normal or CHF dogs. Apocynin caused no change in coronary blood flow (CBF) in normal dogs but increased CBF at rest and during exercise in animals with CHF ( P < 0.05). Intracoronary ACh caused dose-dependent increases of CBF that were blunted in CHF. Apocynin had no effect on the response to ACh in normal dogs but augmented the response to ACh in CHF dogs ( P < 0.05). The oxidative stress markers nitrotyrosine and 4-hydroxy-2-nonenal were significantly greater in failing than in normal myocardium. Furthermore, coelenterazine chemiluminescence for O2− was more than twice normal in failing myocardium, and this difference was abolished by apocynin. Western blot analysis of myocardial lysates demonstrated that the p47phox and p22phox subunits of NADPH were significantly increased in the failing hearts, while real-time PCR demonstrated that Nox2 mRNA was significantly increased. The data indicate that increased ROS generation in the failing heart is associated with coronary endothelial dysfunction and suggest that NADPH oxidase may contribute to this abnormality.


2021 ◽  
Vol 42 (Supplement_1) ◽  
Author(s):  
P Diaba-Nuhoho ◽  
A Shahid ◽  
C Brunssen ◽  
H Morawietz ◽  
H Brendel

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)


2021 ◽  
Vol 77 (18) ◽  
pp. 841
Author(s):  
Petra Lujza Szabo ◽  
Ouafa Hamza ◽  
Milat Inci ◽  
Janine Ebner ◽  
Karlheinz Hilber ◽  
...  

2021 ◽  
Vol 22 (3) ◽  
pp. 1106
Author(s):  
Rayan Bou-Fakhredin ◽  
Batoul Dia ◽  
Hilda E. Ghadieh ◽  
Stefano Rivella ◽  
Maria Domenica Cappellini ◽  
...  

Oxidative damage by reactive oxygen species (ROS) is one of the main contributors to cell injury and tissue damage in thalassemia patients. Recent studies suggest that ROS generation in non-transfusion-dependent (NTDT) patients occurs as a result of iron overload. Among the different sources of ROS, the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase family of enzymes and cytochrome P450 (CYP450) have been proposed to be major contributors for oxidative stress in several diseases. However, the sources of ROS in patients with NTDT remain poorly understood. In this study, Hbbth3/+ mice, a mouse model for β-thalassemia, were used. These mice exhibit an unchanged or decreased expression of the major NOX isoforms, NOX1, NOX2 and NOX4, when compared to their C57BL/6 control littermates. However, a significant increase in the protein synthesis of CYP4A and CYP4F was observed in the Hbbth3/+ mice when compared to the C57BL/6 control mice. These changes were paralleled by an increased production of 20-hydroxyeicosatetraenoic acid (20-HETE), a CYP4A and CYP4F metabolite. Furthermore, these changes corroborate with onset of ROS production concomitant with liver injury. To our knowledge, this is the first report indicating that CYP450 4A and 4F-induced 20-HETE production mediates reactive oxygen species overgeneration in Hbbth3/+ mice through an NADPH-dependent pathway.


2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Yu Chen ◽  
Jingang Cui ◽  
Qinbo Yang ◽  
Chenglin Jia ◽  
Minqi Xiong ◽  
...  

Myocardial fibrosis results from cardiac injuries caused by various pathophysiological mechanisms including myocardial infarction, leading to destruction of myocardial architecture and progressive cardiac dysfunction. Oxidative stress is likely involved in myocardial ischemic injury and the subsequent tissue remodeling mediated by myocardial fibrogenesis. Our current study aimed to evaluate the implication of NADPH oxidase in overproduction of reactive oxygen species and its contribution to the pathogenesis of myocardial fibrogenesis after ischemic injuries. The effects of Apocynin, a selective NADPH oxidase inhibitor, were evaluated in the mouse model of isoproterenol-induced myocardial injury by histopathological approaches and whole-genome gene expression profiling. The results demonstrated that Apocynin was able to inhibit the development of ISO-induced myocardial necrotic lesions and fibrogenesis in a dose-dependent manner. Moreover, the preventive effects of Apocynin on myocardial injuries were associated with suppressed expression of genes implicated in inflammation responses and extracellular matrix, which were remarkably upregulated by isoproterenol administration. In summary, o ur study provides proof-of-concept for the involvement of NADPH oxidase-mediated ROS generation in myocardial ischemic injuries and fibrogenesis, which will benefit the mechanism-based therapeutic development targeting NADPH oxidase and oxidative stress in treating myocardial fibrosis and related disorders.


Hypertension ◽  
2021 ◽  
Vol 78 (Suppl_1) ◽  
Author(s):  
Dan Wang ◽  
Christopher S Wilcox

Introduction and hypothesis: Following bodily entry, the SARS-CoV-2 virus undergoes pulmonary replication with release of circulating viral spike protein 1 (SP1) into the bloodstream. Uptake of SP1 by endothelial cells might provoke vascular dysfunction and thrombosis. We hypothesized that spironolactone could prevent microvascular complications from circulating SP1 in COVID-19. Methods: male C57Bl/6 mice received spironolactone (100 mg · kg -1 · d -1 PO x 3d) or vehicle and intravenous injections of recombinant full-length human SP1 (10 μg per mouse) or vehicle. They were euthanized after 3 days. Mesenteric resistant arterioles (n=4 per group) were dissected and mounted on isometric myographs. Acetylcholine-induced EDRF responses and L-NAME-inhibitable NO generation (DAF-FM fluorescence) were studied in pre-constricted vessels and contraction to endothelin 1 (ET1) or thromboxane (U-46, 619) and ET1-induced ROS (PEG-SOD inhibitable ethidium: dihydroethidium fluorescence) were studied by fluorescence microscopy in other vessels. Results: SP1 reduced acetylcholine-induced EDRF (17 ± 3 vs 27 ± 5 % mean ± sem; P < 0.05) and NO generation (0.21 ± 0.03 vs 0.36 ± 0.04, F 1 /F 0 ; P < 0.05) while increasing contraction to ET1 (10 -7 mol·l -1 : 124 ± 13 vs 89 ± 4 %; P < 0.05) and U-46, 619 (10 -6 mol·l -1 :114± 5 vs 87± 6 %; P < 0.05) and ET1-induced ROS generation(0.30± 0.08 vs 0.09± 0.03; P < 0.05). Spironolactone did not modify any of these responses in vessels from normal mice but prevented all the effects of SP1. Conclusion: these preliminary studies provide a novel model to study COVID-19 vasculopathy. They indicate that spironolactone can provide protection from microvascular oxidative stress, endothelial dysfunction and enhanced contractility and might thereby moderate COVID-19 complications.


PLoS ONE ◽  
2018 ◽  
Vol 13 (11) ◽  
pp. e0206814 ◽  
Author(s):  
Geoffrey Urbanski ◽  
Antoine Caillon ◽  
Caroline Poli ◽  
Gilles Kauffenstein ◽  
Marc-Antoine Begorre ◽  
...  

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Ablikim Abliz ◽  
Chen Chen ◽  
Wenhong Deng ◽  
Weixing Wang ◽  
Rongze Sun

PCBs, widespread endocrine disruptors, cause the disturbance of thyroid hormone (TH) homeostasis in humans and animals. However, the exact mechanism of thyroid dysfunction caused by PCBs is still unknown. In order to clarify the hypotheses that NADPH oxidase (NOX) and subsequent NF-κB pathway may play roles in thyroid dysfunction, sixty Sprague-Dawley rats were randomly divided into four groups: control group, PCB153 treated (PCB) group, received apocynin with PCB153 treatment (APO + PCB) group, and drug control (APO) group. Serum thyroid hormone levels were evaluated. The morphological change of thyroid tissue was analyzed under the light and transmission electron microscopy. NOX2, 8-OHdG, and NF-κB expression in the thyroid tissue was evaluated by immune-histochemical staining. Oxidative stress and inflammatory cytokines were detected. The following results were reduced after apocynin treatment: (1) serum thyroid hormone, (2) thyroid pathological injuries, (3) thyroid MDA, (4) thyroid ultrastructural change, (5) serum inflammatory cytokines, and (6) thyroid expression of NOX2, 8-OHdG, and NF-κB. These results suggested that NOX inhibition attenuates thyroid dysfunction induced by PCB in rats, presumably because of its role in preventing ROS generation and inhibiting the activation of NF-κB pathway. Our findings may provide new therapeutic targets for PCBs induced thyroid dysfunction.


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