Nitrotyrosine Levels Research Articles

Oxidative Stress and Risk of Dementia in Older Patients with Depression: A Longitudinal Cohort Study Using Plasma Biomarkers

Background and Objectives: While depression is associated with an increased risk of Alzheimer’s dementia (AD), traditional AD-related biomarkers, such as amyloid-beta, have shown limited predictive value for late-life depression. Oxidative stress has emerged as a potential indicator given its shared role in both depression and dementia. This study investigated the longitudinal relationship between oxidative stress biomarkers and risk of dementia in patients with depression. Materials and Methods: A longitudinal cohort of 146 older patients with major depressive disorder was analyzed. Biomarkers, such as nitrotyrosine, protein carbonyl, F2-isoprostanes, malondialdehyde, 4-hydroxynonenal, and 8-hydroxy-2′-deoxyguanosine, were collected at baseline and measured using an enzyme-linked immunosorbent assay. AD conversion was determined using comprehensive neuropsychological assessment. Cox proportional hazards models were used to evaluate the association between oxidative stress biomarkers and AD conversion after adjusting for confounders. The log-rank test, using the minimum p-value approach, was applied to determine the optimal cut-off value for significantly associated biomarkers of AD-free survival rates. Results: During the follow-up period ranging from 1.00 to 18.53 years, 41 (28.08%) patients converted to AD. Nitrotyrosine showed a significant association with increased risk of AD (adjusted hazard ratio [HR], 1.01; 95% confidence interval [CI], 1.00–1.01; p = 0.0045). For clinical applicability, patients with plasma nitrotyrosine levels ≥170 nM as the cut-off value had a 5.14-fold increased risk of AD (adjusted HR, 5.14; 95% CI, 2.02–13.07; p = 0.0006). Other biomarkers, such as protein carbonyl, F2-isoprostanes, malondialdehyde, 4-hydroxynonenal, and 8-hydroxy-2′-deoxyguanosine, were not significantly associated with AD conversion. Conclusions: Nitrotyrosine, a biomarker that reflects nitrosative damage, emerged as a significant predictor of dementia risk in older patients with depression, highlighting its potential as an early biomarker of dementia. Further validation of these results is required using a larger sample size.

Anticarcinogenic effects of ursodeoxycholic acid in pancreatic adenocarcinoma cell models.

Changes to the composition of the microbiome in neoplasia, is termed oncobiosis, may affect tumor behavior through the changes to the secretion of bacterial metabolites. In this study we show, that ursodeoxycholic acid (UDCA), a bacterial metabolite, has cytostatic properties in pancreatic adenocarcinoma cell (PDAC) models. UDCA in concentrations corresponding to the human serum reference range suppressed PDAC cell proliferation. UDCA inhibited the expression of epithelial mesenchymal transition (EMT)-related markers and invasion capacity of PDAC cells. UDCA treatment increased oxidative/nitrosative stress by reducing the expression of nuclear factor, erythroid 2-like 2 (NRF2), inducing inducible nitric oxide synthase (iNOS) and nitrotyrosine levels and enhancing lipid peroxidation. Furthermore, UDCA reduced the expression of cancer stem cell markers and the proportion of cancer stem cells. Suppression of oxidative stress by antioxidants, blunted the UDCA-induced reduction in cancer stemness. Finally, we showed that UDCA induced mitochondrial oxidative metabolism. UDCA did not modulate the effectiveness of chemotherapy agents used in the chemotherapy treatment of pancreatic adenocarcinoma. The antineoplastic effects of UDCA, observed here, may contribute to the induction of cytostasis in PDAC cell models by providing a more oxidative/nitrosative environment.

Assessment of Serum Dynamic Thiol/Disulfide Homeostasis and Oxidative/Nitrosative Stress in Patients with Crohn's Disease.

Crohn's disease (CD) is a major subtype of chronic relapsing inflammatory gastrointestinal disorders. In this study, we assessed the possible contributions of serum oxidative/nitrosative stress and dynamic thiol/disulfide homeostasis to CD pathogenesis. Patients with active CD (A-CD) at onset (n = 38), CD patients in the remission (R-CD) (n = 38), and healthy controls (n = 38) were prospectively included in this study. Serum oxidative/nitrosative parameters as well as total thiol and native thiol levels were analyzed. We observed significant augmentation in nitric oxide (NO) levels in both A-CD and R-CD patients compared to healthy controls. We detected marked reductions in the 3-nitrotyrosine levels in the patient groups. Glutathione, glutathione peroxidase, and myeloperoxidase levels were observed to be significantly lower in both the active and remission groups (P < .001). In the A-CD group, native thiol (P < .001) and total thiol (P < .01) levels were lower, and disulfide levels were higher than those of the control group (P < .01), while the native thiol/total thiol ratio was reduced and disulfide/total thiol (P < .001) and disulfide/native thiol (P < .001) ratios were elevated. Remarkably, no change in dynamic thiol/disulfide homeostasis was found in the R-CD group. Our results showed increased serum NO levels and decreased antioxidant enzymes, particularly during the active phase of CD. Determination of thiol/disulfide homeostasis could help differentiate between the active and remission phases of the disease. Thiol/ disulfide parameters can be used as biomarkers for A-CD.

Anorexigenic and anti-inflammatory signaling pathways of semaglutide via the microbiota-gut--brain axis in obese mice.

Our study focused on a mouse model of obesity induced by a high-fat diet (HFD). We administered Semaglutide intraperitoneally (Ozempic ®-0.05mg/Kg-translational dose) every seven days for six weeks. HFD-fed mice had higher blood glucose, lipid profile, and insulin resistance. Moreover, mice fed HFD showed high gut levels of TLR4, NF-kB, TNF-α, IL-1β, and nitrotyrosine and low levels of occludin, indicating intestinal inflammation and permeability, culminating in higher serum levels of IL-1β and LPS. Treatment with semaglutide counteracted the dyslipidemia and insulin resistance, reducing gut and serum inflammatory markers. Structural changes in gut microbiome were determined by 16S rRNA sequencing. Semaglutide reduced the relative abundance of Firmicutes and augmented that of Bacteroidetes. Meanwhile, semaglutide dramatically changed the overall composition and promoted the growth of acetate-producing bacteria (Bacteroides acidifaciens and Blautia coccoides), increasing hypothalamic acetate levels. Semaglutide intervention increased the number of hypothalamic GLP-1R+ neurons that mediate endogenous action on feeding and energy. In addition, semaglutide treatment reversed the hypothalamic neuroinflammation HDF-induced decreasing TLR4/MyD88/NF-κB signaling and JNK and AMPK levels, improving the hypothalamic insulin resistance. Also, semaglutide modulated the intestinal microbiota, promoting the growth of acetate-producing bacteria, inducing high levels of hypothalamic acetate, and increasing GPR43+ /POMC+ neurons. In the ARC, acetate activated the GPR43 and its downstream PI3K-Akt pathway, which activates POMC neurons by repressing the FoxO-1. Thus, among the multifactorial effectors of hypothalamic energy homeostasis, possibly higher levels of acetate derived from the intestinal microbiota contribute to reducing food intake.

Anti-inflammatory and antioxidative effects of bioactive peptides IKW and RIY in spontaneously hypertensive rats and angiotensin II-stimulated vascular smooth muscle cells

The chicken muscle-derived peptide IKW and the rapeseed-derived peptide RIY are two previously identified anti-hypertensive peptides that up-regulate angiotensin-converting enzyme 2 (ACE2). Given the interplay between hypertension and vascular inflammation and oxidation, this study investigated the potential anti-inflammatory and antioxidative activities of IKW and RIY in the aorta of spontaneously hypertensive rats (SHRs) and angiotensin II (Ang II)-stimulated vascular smooth muscle cells (VSMCs). SHRs were orally administered 15 mg peptides/kg body weight for 7 days, leading to reduced vascular inflammation and oxidative stress through the modulation of mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-κB) pathways, decreased aortic nitrotyrosine and intracellular calcium levels, and shifts in the oxylipin profile towards anti-inflammatory species. Meanwhile, VSMCs treated with peptides (50 μM), with or without suramin (10 μM), under Ang II stimulation (1 μM or 10 nM), showed reduced levels of reactive oxygen species, intracellular calcium, interleukin-1β, and cyclooxygenase 2 (COX2). The inhibitory effects on COX2 were partially mediated by ACE2 and sirtuin-1 (SIRT1) upregulation, with SIRT1 contributing to ACE2 expression, as knocking down ACE2 or blocking SIRT1 attenuated these effects. Overall, our results confirm that peptides IKW and RIY exhibit anti-inflammatory and antioxidative effects in the vasculature of SHRs and in Ang II stimulated VSMCs.

Carvedilol through ß1-Adrenoceptor blockade ameliorates glomerulonephritis via inhibition of oxidative stress, apoptosis, autophagy, ferroptosis, endoplasmic reticulum stress and inflammation

Glomerulonephritis (GN) is one of the main causes of end stage renal disease and requires an effective treatment for inhibiting GN. Renal nerves through efferent (RENA) and afferent (RANA) innervation to glomeruli regulate the glomerular function. We delineated the role of RENA and RANA on anti-Thy1.1-induced GN. Female Wistar rats were divided into Control, Thy1.1 plus anti-Thy1.1, bilaterally renal nerve denervation (DNX) plus anti-Thy1.1, and topical capsaicin to bilateral renal nerves for selective ablation of RANA (DNAX) plus anti-Thy1.1. We examined RANA and RENA response to anti-Thy1.1 and compared the effect of DNX or DNAX on urinary oxidative stress, renal gp91, tyrosine hydroxylase (TH), calcitonin gene-related peptide (CGRP), apoptosis, autophagy, ferroptosis, antioxidant enzymes, endoplasmic reticulum (ER) stress and inflammation by western blot. Anti-Thy1.1 significantly enhanced RENA, but did not affect RANA. DNX significantly decreased TH and CGRP expression, whereas DNAX only reduced CGRP expression. Anti-Thy1.1 significantly increased glomerulosclerosis injury, urinary protein, electron paramagnetic resonance signals of alpha-(4-pyridyl-N-oxide)-N-tert-butylnitrone adducts, 8-isoprostane and nitrotyrosine levels, NADPH oxidase gp91phox (gp91), macrophage/monocyte (ED-1), GRP-78, Beclin-1/LC3-II, Bax/caspase-3/poly(ADP-ribose) polymerase expression, inflammatory cytokines levels and decreased renal Copper/Zinc superoxide dismutase, Cystine/glutamate transporter (xCT) and Glutathione peroxidase 4 (GPX4) expression vs. Control. The enhanced oxidative parameters or reduced antioxidant defense by anti-Thy1.1 were significantly attenuated by DNX but not DNAX. Additionally, oral ß1-adrenoceptor antagonist-Carvedilol at an early stage reduced anti-Thy1.1 increased proteinuria level and oxidative parameters. Our data suggest that DNX and ß1-adrenoceptor antagonist-Carvedilol efficiently attenuate oxidative stress, inflammation, ER stress, autophagy, ferroptosis and apoptosis in GN.

Post-myocardial infarction heart failure and long-term high-fat diet: Cardiac endoplasmic reticulum stress and unfolded protein response in Sprague Dawley rat model.

Myocardial infarction (MI) significantly contributes to the global mortality rate, often leading to heart failure (HF) due to left ventricular remodeling. Key factors in the pathomechanism of HF include nitrosative/oxidative stress, inflammation, and endoplasmic reticulum (ER) stress. Furthermore, while a high-fat diet (HFD) is known to exacerbate post-MI cardiac remodeling, its impact on these critical factors in the context of HF is not as well understood. This study aimed to assess the impact of post-MI HF and HFD on inflammation, nitro-oxidative stress, ER stress, and unfolded protein response (UPR). The study was performed on fragments of the left ventricle harvested from 30 male adult Sprague Dawley rats, which were divided into four groups based on diet (normal-fat vs. high-fat) and surgical procedure (sham operation vs. coronary artery ligation to induce MI). We assessed body weight, NT-proBNP levels, protein levels related to nitrosative/oxidative stress, ER stress, UPR, apoptosis, and nitric oxide synthases, through Western Blot and ELISA. HFD and MI significantly influenced body weight and NT-proBNP concentrations. HFD elevated 3-nitrotyrosine and myeloperoxidase levels and altered nitric oxide synthase levels. HFD and MI significantly affected ER stress markers and activated or inhibited UPR pathways. The study demonstrates significant impacts of post-MI HF and dietary fat content on cardiac function and stress markers in a rat model. The interaction between HFD and MI on UPR activation suggests the importance of dietary management in post-MI recovery and HF prevention.

O48 CHRONIC EXPOSURE TO POLLUTED URBAN AIR ALTERS MOUSE SYSTEMIC AND TISSUE-SPECIFIC COMPONENTS OF THE RENIN-ANGIOTENSIN SYSTEM (RAS)

Background and Objective: Chronic exposure to air pollution induces pulmonary, cardiovascular, and renal diseases. In the current study, we investigated the hypothesis that postulates that a dysregulation of the RAS may contribute to these pathologies. Methods: Male Balb/C mice were exposed to urban air from Buenos Aires City, in whole-body exposure chambers for 14 weeks. Control animals were exposed to filtered air. The levels of main RAS components including angiotensin-converting enzyme (ACE) and ACE2; AT1, AT2, and Mas receptors (R) were determined in mouse lungs, kidneys, and heart, through western blotting (WB) and RT-qPCR, respectively. The tissue content of cytokine mARN was determined by RT-qPCR. The tissue content of nitrotyrosine and 4-hydroxynonenal (4-HNE) levels, were determined by WB. Circulating angiotensin (Ang) II levels were determined by radioimmunoassay. Systolic blood pressure was measured by the tail-cuff method. Results: Exposure to air pollution resulted in a) Increased levels of ACE and AT1R mRNA in the lungs and augmented the abundance markers of inflammation (TNF-α, IL-6, and IL-1β) and oxidative stress (nitrotyrosine and 4-HNE) in this tissue, b) increased levels of MasR mRNA (all analyzed tissues) and MasR protein levels (lungs and heart), c) upregulated mRNA and protein abundance of cardiac and renal AT2Rs, and d) Increased levels of circulating Ang II and e) augmented systolic blood pressure. Conclusions: Our findings indicate that chronic exposure to air pollution alters the expression of both tissue and systemic components of the RAS. Since both AT2R and MasRs have been shown to participate in tissue-repair mechanisms, the upregulation of these receptors detected in mouse lungs, heart, and kidney after chronic exposure to polluted urban air could represent a mechanism of tissue protection against damage induced by air pollution.

Effects of empagliflozin and dapagliflozin on serum humanin, MOTS-c levels, nitrosative stress, and ferroptosis parameters in diabetic patients with heart failure

Sodium-glucose cotransporter 2 (SGLT2) inhibitors produce cardioprotective effects on heart failure (HF), even in the absence of diabetes. However, the underlying mechanisms of this cardioprotective effect remain unexplored. The purpose of this study was to examine the effects of SGLT2 inhibitors on serum MOTS-c, humanin levels, nitrosative stress, and ferroptosis parameters in diabetic patients with HF with reduced ejection fraction (HFrEF). A total of 74 adult diabetic patients with HFrEF and 37 healthy controls were included in this prospective study. Half of the patients were using SGLT2 inhibitors (empagliflozin or dapagliflozin) for at least two months. Serum nitric oxide and 3-nitrotyrosine levels were markedly higher in diabetic patients with HFrEF than the control (P < 0.001), but these elevations were inhibited with SGLT2 inhibitors. Although SGLT2 inhibitors had no marked effect on humanin levels, they significantly augmented MOTS-c levels when compared to the control. SGLT2 inhibitors augmented GPX4 but inhibited ACSL4 levels when compared to diabetic patients with HF. However, TFRC levels were increased in the patient group (P < 0.001 for all) but not modified with SGLT2 inhibitors. Our results suggest that increased nitrosative stress is significantly depressed by SGLT2 inhibitors. This study was the first to show that SGLT2 inhibitors can stimulate MOTS-c, but not humanin, in diabetic patients with HFrEF. SGLT2 inhibitors reduced ferroptosis through elevation of GPX4 and suppression of ACSL4 levels. Our data suggest that SGLT2 inhibitors could produce cardioprotective effects through relieving ferroptosis, inhibiting nitosative stress, and stimulating mitochondrial MOTS-c release.

STAT3 Regulates the Redox Profile in MDA-MB-231 Breast Cancer Cells.

Unbalanced redox status and constitutive STAT3 activation are related to several aspects of tumor biology and poor prognosis, including metastasis and drug resistance. The triple-negative breast cancer (TNBC) is listed as the most aggressive and exhibits the worst prognosis among the breast cancer subtypes. Although the mechanism of reactive oxygen species (ROS) generation led to STAT3 activation is described, there is no data concerning the STAT3 influence on redox homeostasis in TNBC. To address the role of STAT3 signaling in redox balance, we inhibited STAT3 in TNBC cells and investigated its impact on total ROS levels, contents of hydroperoxides, nitric oxide (NO), and total glutathione (GSH), as well as the expression levels of 3-nitrotyrosine (3NT), nuclear factor (erythroid-derived 2)-like 2 (Nrf2), and nuclear factor kappa B (NF-κB)/p65. Our results indicate that ROS levels depend on the STAT3 activation, while the hydroperoxide level remained unchanged, and NO and 3NT expression increased. Furthermore, GSH levels, Nrf2, and NF-κB/p65 protein levels are decreased in the STAT3-inhibited cells. Accordingly, TNBC patients' data from TCGA demonstrated that both STAT3 mRNA levels and STAT3 signature are correlated to NF-κB/p65 and Nrf2 signatures. Our findings implicate STAT3 in controlling redox balance and regulating redox-related genes' expression in triple-negative breast cancer.

New advances in the protective mechanisms of acidic pH after ischemia: Participation of NO

BackgroundIt has been previously demonstrated that the maintenance of ischemic acidic pH or the delay of intracellular pH recovery at the onset of reperfusion decreases ischemic-induced cardiomyocyte death. ObjectiveTo examine the role played by nitric oxide synthase (NOS)/NO-dependent pathways in the effects of acidic reperfusion in a regional ischemia model. MethodsIsolated rat hearts perfused by Langendorff technique were submitted to 40 min of left coronary artery occlusion followed by 60 min of reperfusion (IC). A group of hearts received an acid solution (pH = 6.4) during the first 2 min of reperfusion (AR) in absence or in presence of l-NAME (NOS inhibitor). Infarct size (IS) and myocardial function were determined. In cardiac homogenates, the expression of P-Akt, P-endothelial and inducible isoforms of NOS (P-eNOS and iNOS) and the level of 3-nitrotyrosine were measured. In isolated cardiomyocytes, the intracellular NO production was assessed by confocal microscopy, under control and acidic conditions. Mitochondrial swelling after Ca2+ addition and mitochondrial membrane potential (Δψ) were also determined under control and acidosis. ResultsAR decreased IS, improved postischemic myocardial function recovery, increased P-Akt and P-eNOS, and decreased iNOS and 3-nitrotyrosine. NO production increased while mitochondrial swelling and Δψ decreased in acidic conditions. l-NAME prevented the beneficial effects of AR. ConclusionsOur data strongly supports that a brief acidic reperfusion protects the myocardium against the ischemia-reperfusion injury through eNOS/NO-dependent pathways.

Sex-specific differences in the mechanisms for enhanced thromboxane A2-mediated vasoconstriction in adult offspring exposed to prenatal hypoxia

BackgroundPrenatal hypoxia, a common pregnancy complication, leads to impaired cardiovascular outcomes in the adult offspring. It results in impaired vasodilation in coronary and mesenteric arteries of the adult offspring, due to reduced nitric oxide (NO). Thromboxane A2 (TxA2) is a potent vasoconstrictor increased in cardiovascular diseases, but its role in the impact of prenatal hypoxia is unknown. To prevent the risk of cardiovascular disease by prenatal hypoxia, we have tested a maternal treatment using a nanoparticle-encapsulated mitochondrial antioxidant (nMitoQ). We hypothesized that prenatal hypoxia enhances vascular TxA2 responses in the adult offspring, due to decreased NO modulation, and that this might be prevented by maternal nMitoQ treatment.MethodsPregnant Sprague–Dawley rats received a single intravenous injection (100 µL) of vehicle (saline) or nMitoQ (125 µmol/L) on gestational day (GD)15 and were exposed to normoxia (21% O2) or hypoxia (11% O2) from GD15 to GD21 (term = 22 days). Coronary and mesenteric arteries were isolated from the 4-month-old female and male offspring, and vasoconstriction responses to U46619 (TxA2 analog) were evaluated using wire myography. In mesenteric arteries, L-NAME (pan-NO synthase (NOS) inhibitor) was used to assess NO modulation. Mesenteric artery endothelial (e)NOS, and TxA2 receptor expression, superoxide, and 3-nitrotyrosine levels were assessed by immunofluorescence.ResultsPrenatal hypoxia resulted in increased U46619 responsiveness in coronary and mesenteric arteries of the female offspring, and to a lesser extent in the male offspring, which was prevented by nMitoQ. In females, there was a reduced impact of L-NAME in mesenteric arteries of the prenatal hypoxia saline-treated females, and reduced 3-nitrotyrosine levels. In males, L-NAME increased U46619 responses in mesenteric artery to a similar extent, but TxA2 receptor expression was increased by prenatal hypoxia. There were no changes in eNOS or superoxide levels.ConclusionsPrenatal hypoxia increased TxA2 vasoconstrictor capacity in the adult offspring in a sex-specific manner, via reduced NO modulation in females and increased TP expression in males. Maternal placental antioxidant treatment prevented the impact of prenatal hypoxia. These findings increase our understanding of how complicated pregnancies can lead to a sex difference in the programming of cardiovascular disease in the adult offspring.Graphical

Evaluation of folliculogenesis and oxidative stress parameters in type 1 diabetes mellitus women with different glycemic profiles.

Despite enormous advances in diabetes treatment, women with type 1 diabetes mellitus (DM) still experience delayed menarche, menstrual irregularities, fewer pregnancies, and a higher rate of stillbirths compared to women without the disease. Due to the fact that type 1 DM occurs at a young age, the preservation of reproductive health is one of the most important goals of treatment. The aim of this study was to evaluate the relationship between different glycemic profiles and changes in the pro-oxidant-antioxidant balance and ovarian follicular apparatus in reproductive-age patients with type 1 DM. We examined 50 reproductive-age (19-38 years) women with type 1 DM with a disease duration of at least ten years. Carbohydrate metabolism was assessed with the continuous glucose monitoring (CGM) system and glycated hemoglobin (HbA1c) concentration measurement. CGM was performed using the FreeStyle Libre flash glucose monitoring system (Abbott Diabetes Care, Witney, UK). In each patient, malondialdehyde level, catalase activity and 3-nitrotyrosine level in the blood serum were determined. To assess the ovarian function, we measured the ovarian volume, the antral follicle count, and the serum levels of anti-Müllerian hormone and follicle-stimulating hormone. All patients were divided into four groups (glucotypes) based on the CGM results. Group 1 included type 1 DM patients with satisfactory compensation of carbohydrate metabolism; group 2 consisted of patients with frequent hypoglycemic conditions and pathological glucose variability; group 3 included individuals with prolonged hyperglycemic conditions and maximum HbA1c levels; and group 4 comprised patients with the glycemic profile characterized by all the presented types of dysglycemia (intermittent glycemia). We revealed a negative correlation between serum catalase activity and time of hypoglycemic conditions in patients with type 1 DM based on the CGM results (rs = -0.47, p < 0.01). In group 4 (intermittent glycemia), patients demonstrated the lowest serum catalase activity and increased serum 3-nitrotyrosine level, while in group 3, women with chronic hyperglycemia (HbA1c 8.4 [8.1; 9.9]%; 68 [65; 85] mmol/mol) had a moderate change in antioxidant defense and oxidative stress parameters. Correlation analysis of ovarian volume, the antral follicle count, and the serum anti-Müllerian hormone level in type 1 DM women with different glycemic profiles established a negative relationship (rs = -0.82, p < 0.05) between the antral follicle count and glucose variability in group 1, a positive relationship (rs = 0.68, p < 0.05) between ovarian volume and glucose variability in group 2, and a positive relationship (rs = 0.88, p < 0.05) between ovarian volume and time of hypoglycemic conditions, which, according to the CGM results, amounted to a critical value of 57.5 [40.0; 82.0]%. The data obtained indicate the relationship between the ovarian volume, serum anti-Müllerian hormone level, the antral follicle count and oxidative stress parameters not only in patients with hyperglycemia, but also in those with hypoglycemic conditions, as well as with pathological glucose variability.

The endocrine disruptor vinclozolin causes endothelial injury via eNOS/Nox4/IRE1α signaling

Vinclozolin (VCZ) is a common dicarboximide fungicide used to protect crops from diseases. It is also an endocrine disruptor, and its effects on various organs have been described but its influence on vasculature has not yet been addressed. This study focuses on the potential mechanism of VCZ-induced vascular injury. The effect of VCZ on vascular function in terms of relaxing and contracting response was evaluated in mice aorta. A short exposure to VCZ affected the endothelial but not the smooth muscle component. Specifically, it caused a disruption of the eNOS/NO signaling. In line, a short exposure to VCZ in bovine aortic endothelial cells promoted eNOS uncoupling resulting in a reduction of NO bioavailability and eNOS dimer/monomer ratio, and in turn an increase of nitro-tyrosine levels and ROS formation. Prolonging the exposure to VCZ (3 and 6h) an up-regulation of Nox4, enzyme-generating ROS constitutively expressed in endothelial cells, and an increase in ROS and malondialdehyde content coupled with a reduction in NO levels were found. These events were strictly linked to endoplasmic reticulum stress as demonstrated by the phosphorylation of inositol-requiring transmembrane kinase endoribonuclease 1α (IRE1α), a stress sensor and its reversion by using a selective inhibitor. Collectively, these results demonstrated that VCZ provokes endothelial dysfunction by oxidative stress involving eNOS/Nox4/IRE1α axis. The rapid exposure affected the endothelial function promoting eNOS uncoupling while a post-transcriptional modification, involving Nox4/IRE1α signaling, occurred following prolonged exposure. Thus, exposure to VCZ could contribute to the onset and/or progression of cardiovascular diseases associated with endothelial dysfunction.

Expression of inducible nitric oxide synthase, nitrotyrosine, eosinophilic peroxidase, eotaxin-3, and galectin-3 in patients with gastroesophageal reflux disease, eosinophilic esophagitis, and in healthy controls: a semiquantitative image analysis of 3,3'-diaminobenzidine-stained esophageal biopsies.

Eosinophilic esophagitis (EoE) and gastroesophageal reflux disease (GERD) share many histopathological features; therefore, markers for differentiation are of diagnostic interest and may add to the understanding of the underlying mechanisms. The nitrergic system is upregulated in GERD and probably also in EoE. Esophageal biopsies of patients with EoE (n = 20), GERD (n = 20), and healthy volunteers (HVs) (n = 15) were exposed to antibodies against inducible nitric oxide synthase (iNOS), nitrotyrosine, eosinophilic peroxidase, eotaxin-3, and galectin-3. The stained object glasses were randomized, digitized, and blindly analyzed regarding the expression of DAB (3,3'-diaminobenzidine) by a protocol developed in QuPath software. A statistically significant overexpression of iNOS was observed in patients with any of the two inflammatory diseases compared with that in HVs. Eotaxin-3 could differentiate HVs versus inflammatory states. Gastroesophageal reflux patients displayed the highest levels of nitrotyrosine. Neither iNOS nor nitrotyrosine alone were able to differentiate between the two diseases. For that purpose, eosinophil peroxidase was a better candidate, as the mean levels increased stepwise from HVs via GERD to EoE. iNOS and nitrotyrosine are significantly overexpressed in patients with EoE and GERD compared with healthy controls, but only eosinophil peroxidase could differentiate the two types of esophagitis. The implications of the finding of the highest levels of nitrotyrosine among gastroesophageal reflux patients are discussed.

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

Effect of Caffeic Acid Phenethyl Ester on Wound Healing: A Systematic Review

Caffeic acid, a naturally occurring organic compound, possesses antioxidant and anti-inflammatory properties, along with its derivatives. This systematic review aimed to evaluate the effect of caffeic acid and its derivatives on oxidative stress and inflammatory response in cutaneous wound healing. This review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. Searches were performed in PubMed, Scopus, and Ovid MEDLINE. Articles published between 2000 and June 2022, with seven articles meeting the inclusion criteria were retrieved. The articles constituted in-vivo studies that utilised caffeic acid phenethyl ester (CAPE) as the therapeutic agent in three types of cutaneous wound including full-thickness burn injury (n=4), two incisional wounds, and one pressure ulcer. CAPE scavenged reactive oxidative species and reduced lipid peroxidation, superoxide dismutase, nitrotyrosine, malondialdehyde, catalase, xanthine oxidase, and nitric oxide levels. The treated injured area revealed enhanced granulation tissue formation, vascularisation, and collagenisation as well as long-term effects of CAPE as evidenced by reduced myofibroblast amount, CD68-positive macrophages, and increased collagen deposition. The systematic review emphasised how antioxidant and anti-inflammatory effects of CAPE could improve the process of wound healing, suggesting its substantial potential for clinical applications in this domain.

Normal Proteasome Function Is Needed to Prevent Kidney Graft Injury during Cold Storage Followed by Transplantation.

Kidney transplantation is the preferred treatment for end-stage kidney disease (ESKD). However, there is a shortage of transplantable kidneys, and donor organs can be damaged by necessary cold storage (CS). Although CS improves the viability of kidneys from deceased donors, prolonged CS negatively affects transplantation outcomes. Previously, we reported that renal proteasome function decreased after rat kidneys underwent CS followed by transplantation (CS + Tx). Here, we investigated the mechanism underlying proteasome dysfunction and the role of the proteasome in kidney graft outcome using a rat model of CS + Tx. We found that the key proteasome subunits β5, α3, and Rpt6 are modified, and proteasome assembly is impaired. Specifically, we detected the modification and aggregation of Rpt6 after CS + Tx, and Rpt6 modification was reversed when renal extracts were treated with protein phosphatases. CS + Tx kidneys also displayed increased levels of nitrotyrosine, an indicator of peroxynitrite (a reactive oxygen species, ROS), compared to sham. Because the Rpt6 subunit appeared to aggregate, we investigated the effect of CS + Tx-mediated ROS (peroxynitrite) generation on renal proteasome assembly and function. We treated NRK cells with exogenous peroxynitrite and evaluated PAC1 (proteasome assembly chaperone), Rpt6, and β5. Peroxynitrite induced a dose-dependent decrease in PAC1 and β5, but Rpt6 was not affected (protein level or modification). Finally, serum creatinine increased when we inhibited the proteasome in transplanted donor rat kidneys (without CS), recapitulating the effects of CS + Tx. These findings underscore the effects of CS + Tx on renal proteasome subunit dysregulation and also highlight the significance of proteasome activity in maintaining graft function following CS + Tx.

Melanoxetin: A Hydroxylated Flavonoid Attenuates Oxidative Stress and Modulates Insulin Resistance and Glycation Pathways in an Animal Model of Type 2 Diabetes Mellitus.

Type 2 diabetes mellitus (DM) continues to escalate, necessitating innovative therapeutic approaches that target distinct pathways and address DM complications. Flavonoids have been shown to possess several pharmacological activities that are important for DM. This study aimed to evaluate the in vivo effects of the flavonoid melanoxetin using Goto-Kakizaki rats. Over a period of 14 days, melanoxetin was administered subcutaneously to investigate its antioxidant, anti-inflammatory, and antidiabetic properties. The results show that melanoxetin reduced insulin resistance in adipose tissue by targeting protein tyrosine phosphatase 1B. Additionally, melanoxetin counteracted oxidative stress by reducing nitrotyrosine levels and modulating superoxide dismutase 1 and hemeoxygenase in adipose tissue and decreasing methylglyoxal-derived hydroimidazolone (MG-H1), a key advanced glycation end product (AGE) implicated in DM-related complications. Moreover, the glyoxalase 1 expression decreased in both the liver and the heart, correlating with reduced AGE levels, particularly MG-H1 in the heart. Melanoxetin also demonstrated anti-inflammatory effects by reducing serum prostaglandin E2 levels, and increasing the antioxidant status of the aorta wall through enhanced acetylcholine-dependent relaxation in the presence of ascorbic acid. These findings provide valuable insights into melanoxetin's therapeutic potential in targeting multiple pathways involved in type 2 DM, particularly in mitigating oxidative stress and glycation.

Inhalation of particulate matter containing environmentally persistent free radicals induces endothelial dysfunction mediated via AhR activation at the air-blood interface.

Particulate matter (PM) containing environmentally persistent free radicals (EPFR) is formed by the incomplete combustion of organic wastes, resulting in the chemisorption of pollutants to the surface of PM containing redox-active transition metals. In prior studies in mice, EPFR inhalation impaired endothelium-dependent vasodilation. These findings were associated with aryl hydrocarbon receptor (AhR) activation in the alveolar type-II (AT-II) cells that form the air-blood interface in the lung. We thus hypothesized that AhR activation in AT-II cells promotes the systemic release of mediators that promote endothelium dysfunction peripheral to the lung. To test our hypothesis, we knocked down AhR in AT-II cells of male and female mice and exposed them to 280 µg/m3 EPFR lo (2.7e + 16 radicals/g) or EPFR (5.5e + 17 radicals/g) compared with filtered air for 4 h/day for 1 day or 5 days. AT-II-AhR activation-induced EPFR-mediated endothelial dysfunction, reducing endothelium-dependent vasorelaxation by 59%, and eNOS expression by 50%. It also increased endothelin-1 mRNA levels in the lungs and peptide levels in the plasma in a paracrine fashion, along with soluble vascular cell adhesion molecule-1 and iNOS mRNA expression, possibly via NF-kB activation. Finally, AhR-dependent increases in antioxidant response signaling, coupled to increased levels of 3-nitrotyrosine in the lungs of EPFR-exposed littermate control but not AT-II AhR KO mice suggested that ATII-specific AhR activation promotes oxidative and nitrative stress. Thus, AhR activation at the air-blood interface mediates endothelial dysfunction observed peripheral to the lung, potentially via release of systemic mediators.