3-Nitrotyrosine in Sera of Patients with Myelodysplastic Syndromes, a Preliminary Study

Abstract Introduction: Myelodysplastic syndromes (MDS) represent a heterogeneous group of clonal stem cell disorders characterized by ineffective hematopoesis, associated with cytopenias and high risk of leukemic transformations with common morbidity. MDS are hematological malignancies of unclear etiology where oxidative/nitrative stress may contribute to the pathogenesis1. The posttranslational oxidative modifications of proteins and low molecular weight compounds are induced, revealing dysbalance of redox systems in vivo. Nitration of tyrosine either in free form or bound in proteins is important marker of nitric oxide synthase (NOS) activity shift in the presence of oxidative stress in favour of superoxide formation. The aim of this work was to assess whether 3-nitrotyrosine (3-NT) serum concentrations are enhanced also in MDS patients. Methods: Serum samples were obtained using blood of either MDS patients or healthy donors. All tested individuals agreed to the study at the time of blood collection. We proposed HPLC-MS/MS method to estimate 3-NT concentration in serum samples using QTRAP 4000 mass spectrometer (ABSciex, Prague, Czech Republic). Serum proteins were precipitated using ethanol, supernatants were evaporated, reconstituted in 0.1% HCOOH/2% methanol and injected onto HALO C18 microcolumn 100x0.5 mm (ABSciex, Prague, Czech Republic). Oxidative stress in MDS patients and controls was assessed by serum malondialdehyde concentrations measured by HPLC of 2-thiobarbituric acid MDA derivative using UV detection. Results: The sensitivity of method proposed for analysis of 3-NT in sera was sufficient for estimation of differences of 3-NT in patients and control samples. We have found enhanced concentrations of both MDA and 3-nitrotyrosine in serum of MDS patients as compared with healthy donors. Discussion: Enhanced MDA concentrations in MDS patients confirmed the presence of oxidative stress in MDS patients. The reactive oxygen species may oxidize tetrahydrobiopterin, important cofactor of NOS, resulting into nitric oxide synthase uncoupling with enhanced superoxide and consequently peroxynitrite production2. It is known that methylarginines, naturally occurring inhibitors of NOS, can profoundly increase superoxide generation from uncoupled NOS. Recently, we have found significantly enhanced concentration of asymmetric dimethylarginine in a serum of middle age patients with myelodysplastic syndrome3. The observed increased concentrations of 3-NT in MDS patients correspond with assumed enhanced peroxynitrite formation as compared with controls. 3-nitrotyrosine concentrations thus could serve as a new criterion of NOS changed activity in MDS patients. Literature: 1. Farquhar MJ, Bowen DT. Oxidative stress and the myelodysplastic syndromes. Int J Hematol. 2003;77:342-350. 2. Pacher P, Beckman JS, Liaudet L. Nitric oxide and peroxynitrite in health and disease. Physiol Rev. 2007;87:315-424. 3. Štikarová J, Suttnar J, Pimková K, Chrastinová-Mášová L, Čermák J, Dyr JE. Enhanced levels of asymmetric dimethylarginine in a serum of middle age patients with myelodysplastic syndrome. Journal of Hematology & Oncology. 2013;6:58. Disclosures No relevant conflicts of interest to declare.

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Asymmetric dimethylarginine, oxidative stress, and vascular nitric oxide synthase in essential hypertension

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.90506.2008 ◽

2009 ◽

Vol 296 (2) ◽

pp. R195-R200 ◽

Cited By ~ 67

Author(s):

Dan Wang ◽

Svend Strandgaard ◽

Jens Iversen ◽

Christopher S. Wilcox

Keyword(s):

Oxidative Stress ◽

Nitric Oxide ◽

Blood Pressure ◽

Essential Hypertension ◽

Nitric Oxide Synthase ◽

Plasma Levels ◽

Asymmetric Dimethylarginine ◽

Lipid Peroxidation Product ◽

Individual Values ◽

Oxide Synthase

We reported impaired endothelium-derived relaxation factor/nitric oxide (EDRF/NO) responses and constitutive nitric oxide synthase (cNOS) activity in subcutaneous vessels dissected from patients with essential hypertension ( n = 9) compared with normal controls ( n = 10). We now test the hypothesis that the patients in this study have increased circulating levels of the cNOS inhibitor, asymmetric dimethylarginine (ADMA), or the lipid peroxidation product of linoleic acid, 13-hydroxyoctadecadienoic acid (HODE), which is a marker of reactive oxygen species. Patients had significantly ( P < 0.001) elevated (means ± SD) plasma levels of ADMA (PADMA, 766 ± 217 vs. 393 ± 57 nmol/l) and symmetric dimethylarginine (PSDMA: 644 ± 140 vs. 399 ± 70 nmol/l) but similar levels of l-arginine accompanied by significantly ( P < 0.015) increased rates of renal ADMA excretion (21 ± 9 vs. 14 ± 5 nmol/μmol creatinine) and decreased rates of renal ADMA clearance (18 ± 3 vs. 28 ± 5 ml/min). They had significantly increased plasma levels of HODE (PHODE: 309 ± 30 vs. 226 ± 24 nmol/l) and renal HODE excretion (433 ± 93 vs. 299 ± 67 nmol/μmol creatinine). For the combined group of normal and hypertensive subjects, the individual values for plasma levels of ADMA and HODE were both significantly ( P < 0.001) and inversely correlated with microvascular EDRF/NO and positively correlated with mean blood pressure. In conclusion, elevated levels of ADMA and oxidative stress in a group of hypertensive patients could contribute to the associated microvascular endothelial dysfunction and elevated blood pressure.

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Asymmetric dimethylarginine, an endogenous inhibitor of nitric oxide synthase, in maternal and fetal circulation

Journal of the Society for Gynecologic Investigation ◽

10.1016/s1071-5576(02)00192-2 ◽

2003 ◽

Vol 10 (1) ◽

pp. 2-4 ◽

Cited By ~ 14

Author(s):

T Maeda

Keyword(s):

Nitric Oxide ◽

Nitric Oxide Synthase ◽

Asymmetric Dimethylarginine ◽

Endogenous Inhibitor ◽

Fetal Circulation ◽

Oxide Synthase

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Elevated plasma concentrations of the endogenous nitric oxide synthase inhibitor asymmetric dimethylarginine in citrullinemia

Metabolism ◽

10.1016/j.metabol.2006.07.020 ◽

2006 ◽

Vol 55 (12) ◽

pp. 1599-1603 ◽

Cited By ~ 15

Author(s):

Thomas Lücke ◽

Dimitrios Tsikas ◽

Nele Kanzelmeyer ◽

Bernhard Vaske ◽

Anibh Martin Das

Keyword(s):

Nitric Oxide ◽

Nitric Oxide Synthase ◽

Asymmetric Dimethylarginine ◽

Plasma Concentrations ◽

Elevated Plasma ◽

Nitric Oxide Synthase Inhibitor ◽

Endogenous Nitric Oxide ◽

Synthase Inhibitor ◽

Oxide Synthase

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Role of TLR-4/IL-6/TNF-α, COX-II and eNOS/iNOS pathways in the impact of carvedilol against hepatic ischemia reperfusion injury

Human & Experimental Toxicology ◽

10.1177/0960327121999442 ◽

2021 ◽

pp. 096032712199944

Author(s):

Mohamed IA Hassan ◽

Fares EM Ali ◽

Abdel-Gawad S Shalkami

Keyword(s):

Oxidative Stress ◽

Nitric Oxide ◽

Nitric Oxide Synthase ◽

Inducible Nitric Oxide Synthase ◽

Liver Enzymes ◽

Ischemia Reperfusion ◽

Hepatic Ischemia ◽

Hepatic Ischemia Reperfusion ◽

Oxide Synthase ◽

Inducible Nitric Oxide

Aim: Hepatic ischemia/reperfusion (I/R) injury is a syndrome involved in allograft dysfunction. This work aimed to elucidate carvedilol (CAR) role in hepatic I/R injury. Methods: Male rats were allocated to Sham group, CAR group, I/R group and CAR plus I/R group. Rats subjected to hepatic ischemia for 30 minutes then reperfused for 60 minutes. Oxidative stress markers, inflammatory cytokines and nitric oxide synthases were measured in hepatic tissues. Results: Hepatocyte injury following I/R was confirmed by a marked increase in liver enzymes. Also, hepatic I/R increased the contents of malondialdehyde however decreased glutathione contents and activities of antioxidant enzymes. Furthermore, hepatic I/R caused elevation of toll-like receptor-4 (TLR-4) expression and inflammatory mediators levels such as tumor necrosis factor-α, interleukin-6 and cyclooxygenase-II. Hepatic I/R caused down-regulation of endothelial nitric oxide synthase and upregulation of inducible nitric oxide synthase expressions. CAR treatment before hepatic I/R resulted in the restoration of liver enzymes. Administration of CAR caused a significant correction of oxidative stress and inflammation markers as well as modulates the expression of endothelial and inducible nitric oxide synthase. Conclusions: CAR protects liver from I/R injury through reduction of the oxidative stress and inflammation, and modulates endothelial and inducible nitric oxide synthase expressions.

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Endothelial PPAR-γ provides vascular protection from IL-1β-induced oxidative stress

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00490.2015 ◽

2016 ◽

Vol 310 (1) ◽

pp. H39-H48 ◽

Cited By ~ 20

Author(s):

Masashi Mukohda ◽

Madeliene Stump ◽

Pimonrat Ketsawatsomkron ◽

Chunyan Hu ◽

Frederick W. Quelle ◽

...

Keyword(s):

Oxidative Stress ◽

Nitric Oxide ◽

Endothelial Dysfunction ◽

Nitric Oxide Synthase ◽

Transgenic Mice ◽

Stress Responses ◽

Endothelial Nitric Oxide Synthase ◽

Ppar Γ ◽

Oxide Synthase ◽

Endothelial Nitric Oxide

Loss of peroxisome proliferator-activated receptor (PPAR)-γ function in the vascular endothelium enhances atherosclerosis and NF-κB target gene expression in high-fat diet-fed apolipoprotein E-deficient mice. The mechanisms by which endothelial PPAR-γ regulates inflammatory responses and protects against atherosclerosis remain unclear. To assess functional interactions between PPAR-γ and inflammation, we used a model of IL-1β-induced aortic dysfunction in transgenic mice with endothelium-specific overexpression of either wild-type (E-WT) or dominant negative PPAR-γ (E-V290M). IL-1β dose dependently decreased IκB-α, increased phospho-p65, and increased luciferase activity in the aorta of NF-κB-LUC transgenic mice. IL-1β also dose dependently reduced endothelial-dependent relaxation by ACh. The loss of ACh responsiveness was partially improved by pretreatment of the vessels with the PPAR-γ agonist rosiglitazone or in E-WT. Conversely, IL-1β-induced endothelial dysfunction was worsened in the aorta from E-V290M mice. Although IL-1β increased the expression of NF-κB target genes, NF-κB p65 inhibitor did not alleviate endothelial dysfunction induced by IL-1β. Tempol, a SOD mimetic, partially restored ACh responsiveness in the IL-1β-treated aorta. Notably, tempol only modestly improved protection in the E-WT aorta but had an increased protective effect in the E-V290M aorta compared with the aorta from nontransgenic mice, suggesting that PPAR-γ-mediated protection involves antioxidant effects. IL-1β increased ROS and decreased the phospho-endothelial nitric oxide synthase (Ser1177)-to-endothelial nitric oxide synthase ratio in the nontransgenic aorta. These effects were completely abolished in the aorta with endothelial overexpression of WT PPAR-γ but were worsened in the aorta with E-V290M even in the absence of IL-1β. We conclude that PPAR-γ protects against IL-1β-mediated endothelial dysfunction through a reduction of oxidative stress responses but not by blunting IL-1β-mediated NF-κB activity.

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