Nitrosative Stress Biomarkers Research Articles

Statins Do Not Significantly Affect Oxidative Nitrosative Stress Biomarkers in the PREVENT Randomized Clinical Trial.

Preventing Anthracycline Cardiovascular Toxicity with Statins (PREVENT) (NCT01988571) randomized breast cancer or lymphoma patients receiving anthracyclines to atorvastatin 40 mg daily or placebo. We evaluated the effects of atorvastatin on oxidative and nitrosative stress biomarkers, and explored whether these biomarkers could explain the lack of effect of atorvastatin on LVEF in PREVENT. Blood samples were collected and cardiac magnetic resonance imaging was performed prior to doxorubicin initiation and at 6 and 24 months. Thirteen biomarkers (arginine-nitric oxide metabolites, paraoxonase-1 [PON-1] activity, and myeloperoxidase) were measured. Dimensionality reduction using principal component analysis was used to define biomarker clusters. Linear mixed-effects models determined the changes in biomarkers over time according to treatment group. Mediation analysis determined if biomarker clusters explained the lack of effect of atorvastatin on LVEF. Among 202 participants with available biomarkers, median age was 53 years; 86.6% had breast cancer; median LVEF was 62%. Cluster 1 levels, reflecting arginine methylation metabolites, were lower over time with atorvastatin, although this was not statistically significant (p=0.081); cluster 2 levels, reflecting PON-1 activity, were significantly lower with atorvastatin (p=0.024). There were no significant changes in other biomarker clusters (p>0.05). Biomarker clusters did not mediate an effect of atorvastatin on LVEF (p>0.05) Conclusions: Atorvastatin demonstrated very modest effects on oxidative/nitrosative stress biomarkers in this low cardiovascular risk population. Our findings provide potential mechanistic insight into the lack of effect of atorvastatin on LVEF in the PREVENT trial.

Comparative analysis of nitrosative stress biomarkers in patients with atopic dermatitis and psoriasis

Comparative analysis of nitrosative stress biomarkers in patients with atopic dermatitis and psoriasis

Significance of nitrosative stress and glycoxidation products in the diagnosis of COVID-19

Significance of nitrosative stress and glycoxidation products in the diagnosis of COVID-19

Boric acid is associated with the suppression of apoptosis and endoplasmic reticulum stress in rat model of paracetamol -induced hepatotoxicity

Paracetamol (also known as acetaminophen or APAP) is an analgesic and antipyretic drug that is widely used all over the world. Boron is an element proven by many studies that it has indispensable effects on human health. In light of the information expressed about boron, we investigated whether there are any effects of boron on paracetamol-induced liver damage. We analyzed the 8-hydroxyguanosine (8-OHG), ALT, AST, glutathione (GSH), malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and nitric oxide (NO) levels in serum or erythrocyte and liver tissue. At the same time, TNF-α, IL-1β, IL-18 levels were examined in liver tissues to determine the effect of boron on inflammation caused by paracetamol in serum and liver tissue. In this study to determine the effect of ER stress-mediated apoptosis, signal transducers that lead the cell to ER stress-mediated apoptosis, IRE1, ATF6 and PERK, caspase 1, 3, 8, 9 and 12, which play a role in the apoptotic process, antiapoptotic factors bcl2, bcl-xL mRNA gene expressions were determined and the effect level of boron on ER stress-mediated apoptosis was determined by immunohistochemical methods. This study demonstrate that boric acid protects against paracetamol-induced liver damage in association with the augmentation of biomarkers of oxidative and nitrosative stress, inflammation and the ER stress / apoptosis axis in rats.

Modulation of the activation of endothelial nitric oxide synthase and nitrosative stress biomarkers by aspirin triggered lipoxins: A possible mechanism of action of aspirin in the antiphospholipid syndrome.

Antiphospholipid syndrome (APS) is characterized by the clinical manifestation of vascular thrombosis (VT) or pregnancy morbidity (PM) and antiphospholipid antibodies (aPL) that can modify the nitric oxide production. Low-dose aspirin is used in the prevention and treatment of diverse alterations of pregnancy. One of the mechanisms of action of aspirin is to induce the production of aspirin-triggered-lipoxins (ATL). The aim of this study was to evaluate the modulatory effect of ATL over the activation of endothelial nitric oxide synthase (eNOS) and nitrosative stress biomarkers induced by aPL. We used polyclonal IgG and sera from women with aPL and PM/VT or VT only, and from women with PM only and positive for non-criteria aPL (SN-OAPS). In these sera, biomarkers of nitrosative stress (nitrites and nitrotyrosine) were measured. The protein expression of nitrotyrosine and the phosphorylation of eNOS (at Ser1177) were estimated in human umbilical vein endothelial cells (HUVECs) stimulated with polyclonal IgG with or without ATL. Women with SN-OAPS showed increased circulating levels of nitrites and nitrotyrosine. Likewise, polyclonal IgG from either SN-OAPS or VT patients stimulated nitrotyrosine expression in HUVECs. ATL decreased the nitrotyrosine expression induced by polyclonal IgG from the SN-OAPS group. ATL also recovered the reduced eNOS phosphorylation at Ser1177 in HUVECs stimulated with polyclonal IgG from women with PM/VT or SN-OAPS. Increased nitrosative stress present in serum of women with SN-OAPS is associated with IgG-mediated impaired endothelial NO synthesis in endothelial cells. ATL prevent these cellular changes.

Effects of Normobaric Hypoxia and Adrenergic Blockade over 72 h on Cardiac Function in Rats.

In rats, acute normobaric hypoxia depressed left ventricular (LV) inotropic function. After 24 h of hypoxic exposure, a slight recovery of LV function occurred. We speculated that prolonged hypoxia (72 h) would induce acclimatization and, hence, recovery of LV function. Moreover, we investigated biomarkers of nitrosative stress and apoptosis as possible causes of hypoxic LV depression. To elucidate the role of hypoxic sympathetic activation, we studied whether adrenergic blockade would further deteriorate the general state of the animals and their cardiac function. Ninety-four rats were exposed over 72 h either to normal room air (N) or to normobaric hypoxia (H). The rodents received infusion (0.1 mL/h) with 0.9% NaCl or with different adrenergic blockers. Despite clear signs of acclimatization to hypoxia, the LV depression continued persistently after 72 h of hypoxia. Immunohistochemical analyses revealed significant increases in markers of nitrosative stress, adenosine triphosphate deficiency and apoptosis in the myocardium, which could provide a possible explanation for the absence of LV function recovery. Adrenergic blockade had a slightly deteriorative effect on the hypoxic LV function compared to the hypoxic group with maintained sympathetic efficacy. These findings show that hypoxic sympathetic activation compensates, at least partially, for the compromised function in hypoxic conditions, therefore emphasizing its importance for hypoxia adaptation.

Could circulating biomarkers of nitrosative stress and protein glycoxidation be useful in patients with gastric cancer?

Nitrosative stress leads to protein glycoxidation, but both processes may be strongly related to the cancer development. Therefore, the aim of this study was to assess the nitrosative stress and protein glycoxidation products in patients with gastric cancer in comparison with healthy controls. We are also the first to evaluate the diagnostic utility of nitrosative stress and protein glycoxidation markers in gastric cancer patients in respect to histopathological classifications (TNM, Lauren's and Goseki's classification) and histopathological parameters such as histological type, histological differentiation grade, presence of vascular or neural invasion, desmoplasia and Helicobacter pylori infection. The study included 50 patients with gastric cancer and 50 healthy controls matched for sex and age. Nitrosative stress parameters and protein glycoxidation products were measured colorimetrically/fluorometrically in plasma or serum samples. Student's t-test or Mann-Whitney U-test were used for statistical analysis. NO, S-nitrosothiols, nitrotyrosine, kynurenine, N-formylkynurenine, dityrosine, AGE and Amadori products were significantly increased whereas tryptophan fluorescence was decreased in patients with gastric cancer compared to the healthy control. Nitrosative stress and glycoxidation products may be useful in diagnosis of gastric cancer because they differentiate patients with gastric cancer from healthy individuals with high sensitivity and specificity. Some of the determined parameters are characterised by high AUC value in differentiation of GC patients according to the histopathological parameters. Gastric cancer is associated with enhanced circulating nitrosative stress and protein glycation. Although further research on a tissue model is needed, plasma/serum biomarkers may be dependent on tumour size, histological type, tumour invasion depth, presence of lymph node and distant metastasis, vascular and neural invasion and Helicobacter pylori infection. Thus, circulating biomarkers of nitrosative stress/protein glycoxidation may have potential diagnostic significance in gastric cancer patients.

Biomarkers of nitrosative stress in exhaled breath condensate and serum among patients with cystic fibrosis

PurposeThe measurement of biomarkers in exhaled breath condensate (EBC) offers a non-invasive way to assess airway disease and can be easily done in a clinical setting among patients with cystic fibrosis (CF). The role of oxidative and nitrosative stress in the complex pathophysiology of CF is widely accepted and biomarkers of oxidative and nitrosative stress can be measured in the serum and EBC. To our knowledge, this is the first study to assess markers of nitrosative stress in EBC and serum, collected simultaneously from the CF patients. Patients and methodsPaired EBC and serum samples were collected from 36 stable patients with CF and 14 healthy controls. Markers of nitrosative stress ‒ 3-nitrotyrosine and nitrate/nitrite were measured in the EBC and serum using an enzyme-linked immunosorbent assay. ResultsWe found no differences in 3-nitrotyrosine and nitrate/nitrite in the EBC of patients with CF as compared to healthy controls (125.37 ​± ​3.29 vs. 126.24 ​± ​2.21 ​nmol/L, p ​= ​0.218; 12.66 ​± ​7.23 vs. 8.79 ​± ​4.83 ​μmol/L, p ​= ​0.133, respectively). Furthermore, 3-nitrotyrosine and nitrate/nitrite were significantly higher in the serum of patients with CF as compared to the healthy controls (0.13 ​± ​0.02 vs. 0.11 ​± ​0.01 ​nmol/mg protein, p ​= ​0.003; 70.78 ​± ​22.55 vs. 53.08 ​± ​8.5 ​μmol/L, p ​= ​0.009, respectively). No correlations were found between the markers determined in the EBC and serum. ConclusionsThe results of the EBC nitrosative stress biomarkers should be interpreted with caution, especially in patients with stable disease, as the EBC values may be independent on levels of circulating markers that are elevated in the serum of patients with stable CF.

The NO Answer for Autism Spectrum Disorder.

Autism spectrum disorders (ASDs) include a wide range of neurodevelopmental disorders. Several reports showed that mutations in different high-risk ASD genes lead to ASD. However, the underlying molecular mechanisms have not been deciphered. Recently, they reported a dramatic increase in nitric oxide (NO) levels in ASD mouse models. Here, they conducted a multidisciplinary study to investigate the role of NO in ASD. High levels of nitrosative stress biomarkers are found in both the Shank3 and Cntnap2 ASD mouse models. Pharmacological intervention with a neuronal NO synthase (nNOS) inhibitor in both models led to a reversal of the molecular, synaptic, and behavioral ASD-associated phenotypes. Importantly, treating iPSC-derived cortical neurons from patients with SHANK3 mutation with the nNOS inhibitor showed similar therapeutic effects. Clinically, they found a significant increase in nitrosative stress biomarkers in the plasma of low-functioning ASD patients. Bioinformatics of the SNO-proteome revealed that the complement system is enriched in ASD. This novel work reveals, for the first time, that NO plays a significant role in ASD. Their important findings will open novel directions to examine NO in diverse mutations on the spectrum as well as in other neurodevelopmental disorders. Finally, it suggests a novel strategy for effectively treating ASD.

Furosemide exacerbated the impairment of renal function, oxygenation and medullary damage in a rat model of renal ischemia/reperfusion induced AKI

BackgroundPerioperative acute kidney injury (AKI) caused by ischemia–reperfusion (IR) is a significant contributor to mortality and morbidity after major surgery. Furosemide is commonly used in postoperative patients to promote diuresis and reduce tissue edema. However, the effects of furosemide on renal microcirculation, oxygenation and function are poorly understood during perioperative period following ischemic insult. Herein, we investigated the effects of furosemide in rats subjected IR insult.Methods24 Wistar albino rats were divided into 4 groups, with 6 in each; Sham-operated Control (C), Control + Furosemide (C + F), ischemia/reperfusion (IR), and IR + F. After induction of anesthesia (BL), supra-aortic occlusion was applied to IR and IR + F groups for 45 min followed by ongoing reperfusion for 15 min (T1) and 2 h (T2). Furosemide infusion was initiated simultaneously in the intervention groups after ischemia. Renal blood flow (RBF), vascular resistance (RVR), oxygen delivery (DO2ren) and consumption (VO2ren), sodium reabsorption (TNa+), oxygen utilization efficiency (VO2/TNa+), cortical (CμO2) and medullary (MμO2) microvascular oxygen pressures, urine output (UO) and creatinine clearance (Ccr) were measured. Biomarkers of inflammation, oxidative and nitrosative stress were measured and kidneys were harvested for histological analysis.ResultsIR significantly decreased RBF, mainly by increasing RVR, which was exacerbated in the IR + F group at T2 (2198 ± 879 vs 4233 ± 2636 dyne/s/cm5, p = 0.07). CμO2 (61.6 ± 6.8 vs 86 ± 6.6 mmHg) and MμO2 (51.1 ± 4.1 vs 68.7 ± 4.9 mmHg, p < 0.05) were both reduced after IR and did not improve by furosemide. Moreover, VO2/TNa+ increased in the IR + F group at T2 with respect to the IR group (IR: 3.3 ± 2 vs IR + F: 8.2 ± 10 p = 0.07) suggesting a possible deterioration of oxygen utilization. Ccr did not change, but plasma creatinine increased significantly in IR + F groups. Histopathology revealed widespread damage both in the cortex and medulla in IR, IR + F and C + F groups.ConclusionRenal microvascular oxygenation, renal function, renal vascular resistance, oxygen utilization and damage were not improved by furosemide administration after IR insult. Our study suggests that furosemide may cause additional structural and functional impairment to the kidney following ischemic injury and should be used with caution.

Exposure to engineered nanomaterials and early biological effects measured in the exhaled breath condensate: First results from the NanoExplore cohort

BACKGROUND AND AIM Activities involving engineered nanomaterials (ENM) may raise concerns of occupational exposure and subsequent health effects. We aimed to build a multicenter prospective cohort to assess the potential effects of ENM exposure using biomarkers of early effects measured in exhaled breath condensate (EBC). METHODS We recruited seven centers in three countries (Switzerland, Spain, and Italy), where we conducted a 4-day exposure monitoring campaign and two EBC samplings, at the beginning (T1) and end (T2) of working week. The recruited workers were split in three groups depending on their exposure and compared in terms of their baseline individual and professional characteristics, and health status. EBC biomarkers of oxidative and nitrosative stress (malondialdehyde, 8-isoprostane, nitrotyrosine), systemic inflammation (High-Sensitivity C-Reactive Protein (hsCRP)), activation of pro-fibrotic cascade and interstitial lung disease (Krebs von den Lungen glycoprotein 6 (KL6)) and inflammatory cytokines (Interleukins (IL-10, IL-1β), Tumor necrosis factor (TNF-α)) were analyzed using multilevel mixed interval regression models. RESULTS The cohort included 140 participants: 43 non-exposed, 55 with negligible to low exposure, and 43 with medium to high exposure. The latter were gradually more often men, older, and in overweight than lowly exposed and non-exposed workers. A statistically significant change between T1 and T2 average concentrations was observed for malondialdehyde and KL6. Between-group differences were observed for all biomarkers but KL6 and nitrotyrosine. In multivariate models adjusted for age, sex and body mass index, a linear exposure-response relationship was observed for malondialdehyde, 8-isoprostane, IL-10, IL-1β, and TNF-α. ENM exposure was also associated with higher hs-CRP and KL6 levels, but not monotonically. CONCLUSION These first results suggest that ENM exposure might lead to early biological effects in workers’ airways. These findings need confirmation and a caution interpretation of their clinical significance, as most effects are non-specific and likely reversible.

In Situ Synthesis of a Bismuth Vanadate/Molybdenum Disulfide Composite: An Electrochemical Tool for 3-Nitro-l-Tyrosine Analysis.

The quantification of 3-nitro-l-tyrosine (NO2-Tyr), an in vivo biomarker of nitrosative stress, is indispensable for the clinical intervention of various inflammatory disorders caused by nitrosative stress. By integrating the unique features of BiVO4 and MoS2 with matching bandgap energies, electrode materials with amplified response signals can be developed. In this regard, we introduce a hydrothermally synthesized bismuth vanadate sheathed molybdenum disulfide (MoS2@BiVO4) heterojunction as a highly sensitive electrode material for the determination of NO2-Tyr. Excellent electrochemical behavior perceived for the MoS2@BiVO4 augments the performance of the sensor and allows the measurement of NO2-Tyr in biological media without any time-consuming pretreatments. The synergistic interactions between BiVO4 and MoS2 heterojunctions contribute to low resistance charge transfer (Rct = 159.13 Ω·cm2), a reduction potential Epc = -0.58 V (vs Ag/AgCl), and a good response range (0.001-526.3 μM) with a lower limit of detection (0.94 nM) toward the detection of NO2-Tyr. An improved active surface area, reduced charge recombination, and high analyte adsorption contribute to the high loading of the biomarker for improved selectivity (in the presence of 10 interfering compounds), operational stability (1000 s), and reproducibility (six various modified electrodes). The proposed sensor was successfully utilized for the real-time determination of NO2-Tyr in water, urine, and saliva samples with good recovery values (±98.94-99.98%), ascertaining the reliability of the method. It is noteworthy that the electrochemical activity remains unaffected by other redox interferons, thus leading to targeted sensing applications.

May the Nitrosative and Carbonyl Stress Promote Inflammation in Patients with Colorectal Cancer?

PurposeOverproduction of reactive nitrogen species (RNS) causes the nitrosative stress, which plays a vital role in the development of metabolic, inflammatory, and cancerous diseases. However, the role of nitrosative and carbonyl stress in the biology of colorectal cancer (CRC) is still not well understood. Therefore, this study evaluated nitrosative stress, protein and DNA oxidation/glycoxidation, and pro- and anti-inflammatory cytokines in CRC patients compared with healthy controls.Patients and MethodsFifty-five CRC patients (21 women, 34 men) and 55 healthy controls matched for sex and age were included in the experiment. Nitrosative stress parameters (nitric oxide (NO), peroxynitrite, S-nitrosothiols, and nitrotyrosine), protein oxidation (total thiols) and glycoxidation products (kynurenine N-formylkynurenine, dityrosine, Amadori products, and amyloid), and DNA damage markers (8-hydroxydeoxyguanosine (8-OHdG)), as well as levels of pro- and anti-inflammatory cytokines, were measured in serum or plasma samples.ResultsThe levels of NO, peroxynitrite, S-nitrosothiols, nitrotyrosine, total thiols, kynurenine, N-formylkynurenine, dityrosine, Amadori product, amyloid, and 8-OHdG, as well as IL1α, IL1β, IL6, IL10, and TNF-α, were significantly higher in CRC patients than in controls. Oxidation and glycoxidation products were positively correlated with pro-inflammatory (IL1α, IL1β, IL6, TNFα) and anti-inflammatory cytokines (IL10), indicating that redox damages may promote inflammation in CRC patients. Many redox biomarkers differentiate patients with CRC from healthy individuals with high sensitivity and specificity.ConclusionCorrelations of chosen oxidative products with pro-inflammatory (IL1α, IL1β, IL6, TNFα) and anti-inflammatory cytokines (IL10) suggest that redox damages may promote inflammation in CRC patients. Thus, our research is the first point for further clinical trials focusing on the evaluation of the diagnostic utility of nitrosative stress biomarkers in a larger group of CRC patients.

3-Indolepropionic acid prevented chlorpyrifos-induced hepatorenal toxicities in rats by improving anti-inflammatory, antioxidant, and pro-apoptotic responses and abating DNA damage.

The application of chlorpyrifos (CPF), an organophosphorus pesticide to control insects, is associated with oxidative stress and reduced quality of life in humans and animals. Indole-3-propionic acid (IPA) is a by-product of tryptophan metabolism with high antioxidant capacity and has the potential to curb CPF-mediated toxicities in the hepatorenal system of rats. It is against this background that we explored the subacute exposure of CPF and the effect of IPA in the liver and kidney of thirty rats using five cohort experimental designs (n = 6) consisting of control (corn oil 2mL/kg body weight), CPF alone (5mg/kg), IPA alone (50mg/kg), CPF + IPA1 (5mg/kg + 25mg/kg), and CPF + IPA2 (5mg/kg + 50mg/kg). Subsequently, we evaluated biomarkers of hepatorenal damage, oxidative and nitrosative stress, inflammation, DNA damage, and apoptosis by spectrophotometric and enzyme-linked immunosorbent assay methods. Our results showed that co-treatment with IPA decreased CPF-upregulated serum hepatic transaminases, creatinine, and urea; reversed CPF downregulation of SOD, CAT, GPx, GST, GSH, Trx, TRx-R, and TSH; and abated CPF upregulation of XO, MPO, RONS, and LPO. Co-treatment with IPA decreased CPF-upregulated IL-1β and 8-OHdG levels, caspase-9 and caspase-3 activities, and increased IL-10. In addition, IPA averts CPF-induced histological changes in the liver and kidney of rats. Our results demonstrate that co-dosing CPF-exposed rats with IPA can significantly decrease CPF-induced oxidative stress, pro-inflammatory responses, DNA damage, and subsequent pro-apoptotic responses in rats' liver and kidneys. Therefore, supplementing tryptophan-derived endogenous IPA from exogenous sources may help avert toxicity occasioned by inadvertent exposure to harmful chemicals, including CPF-induced systemic perturbation of liver and kidney function.

Nitric Oxide Therapy Attenuates Heart Failure with Preserved Ejection Fraction

IntroductionNitric oxide (NO) based therapeutics have proven to exert cardioprotective actions in the setting of heart failure with reduced ejection fraction (HFrEF). However, NO therapy has failed to exert beneficial effects in clinical studies of heart failure with preserved ejection fraction (HFpEF).We investigated (1) the effects of the NO donor, sodium nitrite, as a monotherapy, (2) hydralazine monotherapy, a known vasodilator and antioxidant, and (3) combination therapy with both drugs in a murine model of HFpEF. We assessed left ventricular (LV) function, oxidative/nitrosative stress, exercise tolerance, and cardiac fibrosis.Materials and MethodsMale, C57/BL6N (n=15 per group) were placed on a Western high fat diet (60% kCal from fat) and treated with L‐NG‐Nitro arginine methyl ester (L‐NAME, 0.5 g/L/day) in the drinking water beginning at 10 weeks of age. At 15 weeks of age, mice were randomly assigned to four separate groups for five additional weeks: HFpEF control, sodium nitrite in drinking water (75 mg/L), hydralazine (2 mg/kg/day, i.p., b.i.d.), or the combination of sodium nitrite and hydralazine.Plasma was collected to measure circulating 8‐isoprostane and 3‐nitrotyrosine levels, biomarkers of oxidative and nitrosative stress respectively. In addition, cardiac tissue was harvested at 20 weeks for Masson’s Trichrome staining and to measure cardiac nitrite levels. Echocardiography and exercise tolerance testing was performed at 10, 15, and 20 weeks of age.ResultsThere was a significant increase in circulating nitrite levels (p &lt; 0.05) in the sodium nitrite + hydralazine group compared to the control and either monotherapy groups. There was no significant difference in the cardiac tissue nitrite levels between the combination therapy and the control group. Plasma 8‐isoprostane and 3‐nitrotyrosine levels were significantly (p &lt; 0.05) reduced in the sodium nitrite + hydralazine group compared to the HFpEF control group, indicating a reduction in oxidative and nitrosative stress. Although there was no significant difference in the extent of interstitial cardiac fibrosis between groups, there was a significant decrease (p &lt; 0.05) in myocardial perivascular fibrosis in the sodium nitrite + hydralazine group compared to control. Left ventricular end‐diastolic pressure (LVEDP) was significantly reduced in all treatment groups, and LVEDP was reduced to the greatest extent in the nitrite + hydralazine group vs. HFpEF control. Furthermore, we observed a significant (p &lt; 0.01) improvement in LV diastolic function (i.e., E/e’) in the sodium nitrite and hydralazine group that was superior to either of the treatments alone. There was no significant difference in the exercise distance or duration among the various groups.ConclusionThese data demonstrate that the combination of a powerful antioxidant with NO donor therapy significantly enhances the beneficial effects NO therapy in the setting of severe HFpEF.

Associations between Oxidative/Nitrosative Stress and Thyroid Hormones in Pregnant Women-Tainan Birth Cohort Study (TBCS).

Oxidative and nitrosative stress have been linked to thyroid function in both animal and human studies. In the present study, the associations between oxidative and nitrosative stress and thyroid hormones were investigated. Measurements were obtained from 97 Taiwanese pregnant women at the first, second, and third trimesters. Levels of five oxidative and nitrosative stress biomarkers (8-hydroxy-2′-deoxyguanosine [8-OHdG], 8-nitroguanine [8-NO2Gua], 4-hydroxy-2-nonenal-mercapturic acid [HNE-MA], 8-isoprostaglandin F2α [8-isoPGF2α], and malondialdehyde [MDA]) were measured using urine samples, and levels of five thyroid hormones (triiodothyronine [T3], thyroxine [T4], free T4, thyroid-stimulating hormone [TSH], and T4-binding globulin [TBG]) were measured in blood samples. Multiple linear regressions and linear mixed-model regressions were conducted to determine the associations between oxidative or nitrosative stress biomarkers and thyroid hormones in pregnant women. We found that TSH was negatively and significantly associated with 8-NO2Gua (−14%, 95% CI [−26.9% to −1.1%]) and HNE-MA (−23%, 95% CI [−35.9% to −10.0%]) levels. However, T4 (3%, 95% CI [0.2%–5.8%]) and free T4 (4.3%, 95% CI [0.8%–7.8%]) levels were positively and significantly associated with 8-NO2Gua. The T4 to TBG and free T4 to TBG ratios were positively and significantly associated with 8-NO2Gua level (T4/TBG: 3.6%, 95% CI [0.5%–6.7%]; free T4/TBG: 5.6%, 95% CI [0.2%–11.1%]). However, the TSH to T4 ratio was negatively and significantly associated with 8-NO2Gua level (−17.3%, 95% CI [−30.4% to −4.3%]). The T3 to TSH ratio was positively and significantly associated with HNE-MA level (25.2%, 95% CI [11.2%–39.2%]). However, the TSH to T4 and TSH to free T4 ratios were negatively and significantly associated with HNE-MA level (TSH/T4: −21.2%, 95% CI [−34.5% to −7.8%] and TSH/free T4: −24.0%, 95% CI [−38.3% to −9.6%]). Our findings suggest that an imbalance of oxidative and nitrosative stress may alter thyroid hormone homeostasis during pregnancy. Disruption of the maternal thyroid homeostasis during pregnancy would affect embryonic and fetal development.

Salivary gland dysfunction and salivary redox imbalance in patients with Alzheimer\u2019s disease

Alzheimer’s disease (AD) is associated with the deposition of β-amyloid in the brain. AD accounts for over 50% of cases of dementia which results from disturbances in redox homeostasis. Indeed, increased intensity of protein oxidation and nitration as well as lipid peroxidation is observed in brain areas with considerable amounts of amyloid plaques and neurofibrillary tangles. However, little is known about the oxidoreductive balance of salivary glands in AD patients. Therefore, the aim of this study was to evaluate the antioxidant barrier and oxidative/nitrosative stress biomarkers in stimulated saliva and blood of AD patients. The study was participated by 25 AD patients and 25 non-demented controls without neurological diseases or cognitive impairment, matched by age and gender to the study group. The number of patients was determined based on a previous pilot study (test power = 0.9). We found a significant decrease in the activity of erythrocyte superoxide dismutase (SOD) and glutathione peroxidase (GPx), increased activity of catalase (CAT) and reduced concentration of plasma non-enzymatic antioxidants (uric acid, UA and reduced glutathione, GSH). In contrast, in the stimulated saliva of AD patients we observed significantly decreased activity of all antioxidant enzymes (SOD, CAT and GPx) as well as concentration of GSH compared to the control group. The content of lipid (malondialdehyde, MDA) and protein (advanced oxidation protein products, AOPP; advanced glycation end-products, AGE) oxidation products as well as biomarkers of nitrosative stress (peroxynitrite, nitrotyrosine) was significantly higher in both saliva and plasma of AD patients compared to the controls. In AD patients, we also observed a considerable decrease in stimulated saliva secretion and salivary total protein content, and an increase in salivary β-amyloid concentration. In conclusion, AD results in redox imbalance towards oxidative reactions, both at the level of the oral cavity and the entire body. General redox balance disturbances do not coincide with salivary redox balance disturbances. Reduction in stimulated saliva secretion in AD patients reflects secretory dysfunction of the parotid glands.

Inhibition of nitric oxide production enhances the activity of facial nerve tubulin polymerization and the ability of tau to promote microtubule assembly after neurorrhaphy

We previously reported that inhibition of nitric oxide (NO) production promotes rat reconnected facial nerve regeneration. However, the underlying mechanism is obscure. Microtubule assembly is known to be essential to axon regeneration; nevertheless, tubulins and microtubule-associated proteins (MAPs) have been demonstrated as targets for NO and peroxynitrite. Thus, we hypothesized that NO and/or peroxynitrite may affect facial nerve regeneration via influencing on microtubule assembly. First, tubulins and tau (a MAP) were extracted from facial nerves of normal rats, treated with NO donor or peroxynitrite, and processed for microtubule assembly assay. We found that peroxynitrite, DEA NONOate, and Angeli's salt reduced the tubulin polymerization activity to a greater extent than GSNO, SIN-1, and SNAP. Additionally, SIN-1, peroxynitrite, and Angeli's salt impaired the ability of tau to promote microtubule assembly. Next, nitrosative stress biomarkers 3-nitrotyrosine (3-NT) and S-nitrosylated cysteine (SNO-Cys) were immunolabeled in facial nerves. Both biomarkers were highly upregulated in proximal and distal stumps of reconnected facial nerves at 3 days and 1 week after neurorrhaphy. Notably, the expression of 3-NT was greatly reduced at 2 weeks, whereas that of SNO-Cys was maintained. Conversely, inhibition of NO production with L-NAME prevented the upregulation of SNO-Cys. Further, we used tubulins and tau extracted from facial nerves of sham-operated, nerve suture + vehicle treatment, and nerve suture + L-NAME treatment rats to perform microtubule assembly assay. We found that L-NAME treatment enhanced polymerization activity of tubulins and ability of tau to promote microtubule assembly. It is noteworthy that α-tubulin plays a more important role than β-tubulin since the activity of microtubule assembly using α-tubulin extracted from L-NAME-treated rats was greatly elevated, whereas that using β-tubulin extracted from L-NAME-treated rats was not. Overall, our findings support that inhibition of NO production reduces nitrosative stress, and may thus facilitate microtubule assembly and facial nerve regeneration.

Mediation Effects of Oxidative and Nitrosative Stress Biomarkers in the Associations between Phthalate Exposure and Thyroid Function in Taiwanese Adults

BACKGROUND AND AIM: Phthalate exposure was shown to alter thyroid function, however it is unclear, whether oxidative and nitrosative stress explains the intermediate biological mechanism. This study aimed to investigate the associations between phthalate exposure, oxidative/nitrosative stress, and thyroid function in adults, and to examine the mediating role of oxidative/nitrosative stress in the associations between phthalate exposure and thyroid function. METHODS: Levels of eleven urinary phthalate metabolites, three urinary biomarkers of oxidative/nitrosative stress (malondialdehyde [MDA], 8-OHdG, and 8-NO2Gua) and five serum thyroid hormones (thyroxine [T4], free T4, triiodothyronine, thyroid-stimulating hormone, and thyroxine-binding globulin) were measured in 266 Taiwanese adults. Cross-sectional associations between phthalate metabolites, biomarkers of oxidative/ nitrosative stress and thyroid hormones were analyzed using multivariate regression models. Mediation analysis was conducted to assess the role of oxidative/nitrosative stress in the associations between phthalate metabolites and thyroid hormone levels. RESULTS:Sum of di-(2-ethylhexyl) phthalate (DEHP) metabolites was positively associated with MDA (p for trend = 0.005) and 8-NO2Gua (p for trend = 0.045). Mono-n-butyl phthalate (MnBP) was positively associated with 8-NO2Gua (p for trend = 0.018). T4 was negatively associated with MDA (p for trend = 0.005) and 8-NO2Gua (p for trend 0.001). Free T4 was positively associated with MDA (p for trend = 0.047) and with 8NO2Gua (p for trend 0.001). 8-NO2Gua mediated 11% of the association between the sum of DEHP metabolites and T4, and 17% of the association between MnBP and free T4. CONCLUSIONS:These results suggest that phthalate exposure may influence thyroid hormone levels through induced oxidative/nitrosative stress. KEYWORDS: Mediation analysis, Phthalates, Thyroid hormones, Oxidative stress, Nitrosative stress

Nitrosative stress parameters and the level of oxidized DNA bases in patients with multiple sclerosis.

Multiple sclerosis (MS) is a neurodegenerative disease with various factors affecting its etiology. Overproduction of nitric oxide and subsequent lesions of biopolymers are some of the possible causes of the disease. This study aimed to measure the most relevant nitrosative and oxidative stress biomarkers and the level of modified DNA bases in patients with MS. Each parameter was assayed in 25 patients with MS and 25 healthy controls. This study involved detecting blood plasma and serum nitric oxide metabolites by chemiluminescence detector Sievers NOA-280i, malondialdehyde (MDA) measurements with thiobarbituric acid reactive substance (TBARS) assay, detection of oxidized purines and pyrimidines with the enzyme-modified comet assay. Statistical analysis of the results was performed by one-way analysis of variance (ANOVA) and unpaired t test for the comparison of less than three data sets. DNA single-strand breaks, levels of modified purines and pyrimidines, as well as nitrite and nitrate levels in plasma and serum samples, were significantly higher in patients with MS than in healthy controls. On the contrary, MDA levels appeared to be lower in patients with MS.