Evaluating the potential impact of sodium-glucose cotransporter-2 inhibitor "canagliflozin" on the hepatic damage triggered by hypertension in rats.

Hypertension (HTN) is a prevalent chronic disease. HTN and liver disease association is extensively noted. Thus, finding a medication that can alleviate HTN and its accompanying liver insult would be promising. This study investigated the potential impacts of canagliflozin "sodium-glucose cotransporter-2 inhibitor" on the liver of the Nω-nitro-L-arginine methyl ester (L-NAME)-induced HTN rat model. Twenty-four adult male rats were divided into four groups; negative control group, canagliflozin group, L-NAME group: 50 mg/kg of L-NAME was injected daily for 5 weeks and L-NAME + canagliflozin group: 1 week after L-NAME injection both L-NAME + canagliflozin (40 mg/kg) were given concomitantly daily for further 4 weeks. Liver functions, serum lipid profile, hepatic oxidative/nitrative stress biomarkers, gene expression of lipogenic enzymes, B-cell lymphoma 2 (Bcl2), and DNA fragmentation, were measured. Besides, hepatic histology and immunohistochemistry of nuclear factor kappa B (NF-κB) and endothelial nitric oxide synthase (eNOS) were assessed. Canagliflozin improved hepatic lipogenesis via the downregulation of fatty acid synthase (FAS) and transcriptional regulatory element binding protein 1c (SREBP1c) genes leading to an improved serum lipid profile. Further, canagliflozin modified the eNOS/inducible nitric oxide synthase (iNOS) pathway and decreased the NF-κB immunoreactivity besides restoring the oxidants-antioxidants balance; increased reduced glutathione concomitant with declined malondialdehyde. This improvement of the liver was mirrored by the significant restoration of liver architecture and confirmed by the preserved liver DNA content and upregulation of the antiapoptotic Bcl2 mRNA level and attenuation of the alanine transaminase, aspartate aminotransferase. In conclusion, canagliflozin is a promising anti-hypertensive and hepatic-supportive medication. RESEARCH HIGHLIGHTS: Canagliflozin's antioxidant, anti-inflammatory, anti-lipogenic, and antiapoptotic characteristics mitigate remote liver compromise caused by hypertension. Canagliflozin can be exploited as a hepatoprotective and antihypertensive medication.

Histological, biochemical and immunohistochemical assessments of Roundup®, atrazine, and 2,4-D mixtures on tissue architecture, body fluid conditions, nitrotyrosine protein and Na+/K+-ATPase expressions in the American oyster, Crassostera virginica.

Pesticides are widely used to control weeds and pests in agricultural settings but harm non-target aquatic organisms. In this study, our objective was to evaluate the effect of short-term exposure (one week) to environmentally relevant concentrations of pesticides mixture (low concentration: 0.4 µg/l atrazine, 0.5 µg/l Roundup®, and 0.5 µg/l 2,4-D; high concentration: 0.8 µg/l atrazine, 1 µg/l Roundup®, and 1 µg/l 2,4-D) on tissue architecture, body fluid conditions, and 3-nitrotyrosine protein (NTP) and Na+/K+-ATPase, expressions in tissues of American oyster (Crassostrea virginica) under controlled laboratory conditions. Histological analysis demonstrated the atrophy in the gills and digestive glands of oysters exposed to pesticides mixture. Periodic acid-Schiff (PAS) staining showed the number of hemocytes in connective tissue increased in low- and high-concentration pesticides exposure groups. However, pesticides treatment significantly (P < 0.05) decreased the amount of mucous secretion in the gills and digestive glands of oysters. The extrapallial fluid (i.e., body fluid) protein concentrations and glucose levels were dropped significantly (P < 0.05) in oysters exposed to high-concentration pesticides exposure groups. Moreover, immunohistochemical analysis showed significant upregulations of NTP and Na+/K+-ATPase expressions in the gills and digestive glands in pesticides exposure groups. Our results suggest that exposure to environmentally relevant pesticides mixture causes morphological changes in tissues and alters body fluid conditions and NTP and Na+/K+-ATPase expressions in tissues, which may lead to impaired physiological functions in oysters.

Assessment of cerebrovascular alterations induced by inflammatory response and oxidative-nitrative stress after traumatic intracranial hypertension and a potential mitigation strategy.

The rapid perfusion of cerebral arteries leads to a significant increase in intracranial blood volume, exposing patients with traumatic brain injury to the risk of diffuse brain swelling or malignant brain herniation during decompressive craniectomy. The microcirculation and venous system are also involved in this process, but the precise mechanisms remain unclear. A physiological model of extremely high intracranial pressure was created in rats. This development triggered the TNF-α/NF-κB/iNOS axis in microglia, and released many inflammatory factors and reactive oxygen species/reactive nitrogen species, generating an excessive amount of peroxynitrite. Subsequently, the capillary wall cells especially pericytes exhibited severe degeneration and injury, the blood-brain barrier was disrupted, and a large number of blood cells were deposited within the microcirculation, resulting in a significant delay in the recovery of the microcirculation and venous blood flow compared to arterial flow, and this still persisted after decompressive craniectomy. Infliximab is a monoclonal antibody bound to TNF-α that effectively reduces the activity of TNF-α/NF-κB/iNOS axis. Treatment with Infliximab resulted in downregulation of inflammatory and oxidative-nitrative stress related factors, attenuation of capillary wall cells injury, and relative reduction of capillary hemostasis. These improved the delay in recovery of microcirculation and venous blood flow.

Quantitative profiling of cochlear synaptosomal proteins in cisplatin-induced synaptic dysfunction.

The disruption of ribbon synapses in the cochlea impairs the transmission of auditory signals from the cochlear sensory receptor cells to the auditory cortex. Although cisplatin-induced loss of ribbon synapses is well-documented, and studies have reported nitration of cochlear proteins after cisplatin treatment, yet the underlying mechanism of cochlear synaptopathy is not fully understood. This study tests the hypothesis that cisplatin treatment alters the abundance of cochlear synaptosomal proteins, and selective targeting of nitrative stress prevents the associated synaptic dysfunction. Auditory brainstem responses of mice treated with cisplatin showed a reduction in amplitude and an increase in latency of wave I, indicating cisplatin-induced synaptic dysfunction. The mass spectrometry analysis of cochlear synaptosomal proteins identified 102 proteins that decreased in abundance and 249 that increased in abundance after cisplatin treatment. Pathway analysis suggested that the dysregulated proteins were involved in calcium binding, calcium ion regulation, synapses, and endocytosis pathways. Inhibition of nitrative stress by co-treatment with MnTBAP, a peroxynitrite scavenger, attenuated cisplatin-induced changes in the abundance of 27 proteins. Furthermore, MnTBAP co-treatment prevented the cisplatin-induced decrease in the amplitude and increase in the latency of wave I. Together, these findings suggest a potential role of oxidative/nitrative stress in cisplatin-induced cochlear synaptic dysfunction.

Age-induced nitrative stress decreases retrograde transport of proNGF via TrkA and increases proNGF retrograde transport and neurodegeneration via p75NTR.

Introduction: Axonal transport of pro nerve growth factor (proNGF) is impaired in aged basal forebrain cholinergic neurons (BFCNs), which is associated with their degeneration. ProNGF is neurotrophic in the presence of its receptor tropomyosin-related kinase A (TrkA) but induces apoptosis via the pan-neurotrophin receptor (p75NTR) when TrkA is absent. It is well established that TrkA is lost while p75NTR is maintained in aged BFCNs, but whether aging differentially affects transport of proNGF via each receptor is unknown. Nitrative stress increases during aging, but whether age-induced nitrative stress differentially affects proNGF transport via TrkA versus p75NTR has not yet been studied. Answering these questions is essential for developing an accurate understanding of the mechanisms contributing to age-induced loss of proNGF transport and BFCN degeneration. Methods: In this study, fluorescence microscopy was used to analyze axonal transport of quantum dot labeled proNGF in rat BFCNs in vitro. Receptor specific effects were studied with proNGF mutants that selectively bind to either TrkA (proNGF-KKE) or p75NTR (proNGF-Δ9-13). Signaling factor activity was quantified via immunostaining. Results: Young BFCNs transported proNGF-KKE but not proNGF-Δ9-13, and proNGF transport was not different in p75NTR knockout BFCNs compared to wildtype BFCNs. These results indicate that young BFCNs transport proNGF via TrkA. In vitro aging increased transport of proNGF-Δ9-13 but decreased transport of proNGF-KKE. Treatment with the nitric oxide synthase inhibitor L-NAME reduced retrograde transport of proNGF-Δ9-13 in aged BFCNs while increasing retrograde transport of proNGF-KKE but did not affect TrkA or p75NTR levels. ProNGF-Δ9-13 induced greater pro-apoptotic signaling and neurodegeneration and less pro-survival signaling relative to proNGF-KKE. Discussion: Together, these results indicate that age-induced nitrative stress decreases proNGF transport via TrkA while increasing proNGF transport via p75NTR. These transport deficits are associated with decreased survival signaling, increased apoptotic signaling, and neurodegeneration. Our findings elucidate the receptor specificity of age-and nitrative stress-induced proNGF transport deficits. These results may help to rescue the neurotrophic signaling of proNGF in aging to reduce age-induced loss of BFCN function and cognitive decline.

Molecular and biochemical biomarkers in the American oyster Crassostrea virginica exposed to herbicide Roundup® at high temperature.

Aquatic organisms are frequently exposed to various environmental stressors. Thus, the effects of high temperatures and herbicides on aquatic organisms are a major subject of interest. In this study, we studied the effects of short-term exposure (1 week) to Roundup®, a glyphosate-based herbicide (concentrations: 0.5 and 5 µg/L), on the morphology of gills, digestive glands, and connective tissues, and the expression of heat shock protein-70 (HSP70, a chaperone protein), cytochrome P450 (CYP450, a biomarker of environmental contaminants), dinitrophenyl protein (DNP, a biomarker of protein oxidation), nitrotyrosine protein (NTP, a biomarker of protein nitration), antioxidant enzymes such as superoxidase dismutase (SOD) and catalase (CAT) in tissues of American oyster, Crassostrea virginica (Gmelin, 1791) maintained at high temperature (30 °C). Histological analyses showed an increase in mucous production in the gills and digestive glands, and in hemocyte aggregation in the connective tissues as well as a structural change of lumen in the digestive glands of oysters exposed to Roundup. Immunohistochemical and quantitative RT-PCR analyses showed significant (P < 0.05) increases in HSP70, CYP450, DNP, NTP, CAT, and SOD mRNA and protein expressions in the tissues of oysters exposed to Roundup. Taken together, these results suggest that exposure to Roundup at high temperature induces overproduction of reactive oxygen species/reactive nitrogen species which in turn leads to altered prooxidant-antioxidant activity in oyster tissues. Moreover, our results provide new information on protein oxidation/nitration and antioxidant-dependent mechanisms for HSP70 and CYP450 regulations in oysters exposed to Roundup at high temperature.

Endothelial MICU1 alleviates diabetic cardiomyopathy by attenuating nitrative stress-mediated cardiac microvascular injury.

BACKGROUND: Myocardial microvascular injury is the key event in early diabetic heart disease. The injury of myocardial microvascular endothelial cells (CMECs) is the main cause and trigger of myocardial microvascular disease. Mitochondrial calcium homeostasis plays an important role in maintaining the normal function, survival and death of endothelial cells. Considering that mitochondrial calcium uptake 1 (MICU1) is a key molecule in mitochondrial calcium regulation, this study aimed to investigate the role of MICU1 in CMECs and explore its underlying mechanisms. METHODS: To examine the role of endothelial MICU1 in diabetic cardiomyopathy (DCM), we used endothelial-specific MICU1ecKO mice to establish a diabetic mouse model and evaluate the cardiac function. In addition, MICU1 overexpression was conducted by injecting adeno-associated virus 9 carrying MICU1 (AAV9-MICU1). Transcriptome sequencing technology was used to explore underlying molecular mechanisms. RESULTS: Here, we found that MICU1 expression is decreased in CMECs of diabetic mice. Moreover, we demonstrated that endothelial cell MICU1 knockout exacerbated the levels of cardiac hypertrophy and interstitial myocardial fibrosis and led to a further reduction in left ventricular function in diabetic mice. Notably, we found that AAV9-MICU1 specifically upregulated the expression of MICU1 in CMECs of diabetic mice, which inhibited nitrification stress, inflammatory reaction, and apoptosis of the CMECs, ameliorated myocardial hypertrophy and fibrosis, and promoted cardiac function. Further mechanistic analysis suggested that MICU1 deficiency result in excessive mitochondrial calcium uptake and homeostasis imbalance which caused nitrification stress-induced endothelial damage and inflammation that disrupted myocardial microvascular endothelial barrier function and ultimately promoted DCM progression. CONCLUSIONS: Our findings demonstrate that MICU1 expression was downregulated in the CMECs of diabetic mice. Overexpression of endothelial MICU1 reduced nitrification stress induced apoptosis and inflammation by inhibiting mitochondrial calcium uptake, which improved myocardial microvascular function and inhibited DCM progression. Our findings suggest that endothelial MICU1 is a molecular intervention target for the potential treatment of DCM.

Biological Oxidations and Nitrations Promoted by the Hemin-Aß16 Complex.

Both ß-amyloid (Aß) peptides and oxidative stress conditions play key roles in Alzheimer's disease. Hemin contributes to the development of the disease as it possesses redox properties and its level increases in pathological conditions or traumatic brain injuries. The aim of this work was to deepen the investigation of the reactivity of the hemin-Aß16 complex, considering its ability to catalyze oxidation and nitration reactions. We performed kinetic studies in the presence of hydrogen peroxide and nitrite with phenolic and catechol substrates, as well as mass spectrometry studies to investigate the modifications occurring on the peptide itself. The kinetic constants were similar for oxidation and nitration reactions, and their values suggest that the hemin-Aß16 complex binds negatively charged substrates with higher affinity. Mass spectrometry studies showed that tyrosine residue is the endogenous target of nitration. Hemin degradation analysis showed that hemin bleaching is only partly prevented by the coordinated peptide. In conclusion, hemin has rich reactivity, both in oxidation and nitration reactions on aromatic substrates, that could contribute to redox equilibrium in neurons. This reactivity is modulated by the coordination of the Aß16 peptide and is only partly quenched when oxidative and nitrative conditions lead to hemin degradation.

Analysis of Phosphatidylinositol Modifications by Reactive Nitrogen Species Using LC-MS: Coming to Grips with Their Nitroxidative Susceptibility.

Phosphatidylinositols (PIs) are complex lipids that play a key role in cell signaling. Like other phospholipids, they are esterified with unsaturated fatty acyl residues (FAs), making them susceptible to modification by reactive oxygen and nitrogen species (RNS). Recent studies using mass spectrometry (MS)-based lipidomics approaches have revealed that lipid nitration results in a plethora of structurally and chemically modified lipids (epilipids), including nitrated and nitroxidized derivatives of phosphatidylcholines, phosphatidylethanolamines, phosphatidylserines, and cardiolipins. However, there is a notable lack of knowledge regarding the characterization of RNS-modified PI derivatives. In this study, we used C18 high-resolution liquid chromatography-tandem MS approaches to describe the fragmentation signature of nitrated and nitroxidized PIs, bearing different fatty acyl chains. Using this approach and accurate mass measurements, we were able to identify nitro- PI derivatives, dinitro- and nitrohydroxy- derivatives for a few PI species. The data showed the typical neutral loss of nitrous acid (HNO2) as well as the fragmentation patterns corresponding to modified fatty acyl chains (such as NOx-RCOO-, [M - NOx-RCOOH - H]- and [M - NOx-RCOOH - C6H10O5 - H]-), making it possible to identify these epilipids. The susceptibility of PIs to nitration was also investigated, revealing that it depends exclusively on the chains of unsaturated FAs esterified in PI, showing a higher conversion rate for those with C18:1. Overall, the knowledge gathered in this study will contribute to the precise characterization of these epilipids in complex biological samples, offering new opportunities to unveil the pathophysiological roles of nitrated and nitroxidized PI derivatives at the cellular and tissue levels.

Risk Estimation of Gestational Diabetes Mellitus in the First Trimester.

CONTEXT: There is no early, first-trimester risk estimation available to predict later (gestational week 24-28) gestational diabetes mellitus (GDM); however, it would be beneficial to start an early treatment to prevent the development of complications. OBJECTIVE: We aimed to identify early, first-trimester prediction markers for GDM. METHODS: The present case-control study is based on the study cohort of a Hungarian biobank containing biological samples and follow-up data from 2545 pregnant women. Oxidative-nitrative stress-related parameters, steroid hormone, and metabolite levels were measured in the serum/plasma samples collected at the end of the first trimester from 55 randomly selected control and 55 women who developed GDM later. RESULTS: Pregnant women who developed GDM later during the pregnancy were older and had higher body mass index. The following parameters showed higher concentration in their serum/plasma samples: fructosamine, total antioxidant capacity, testosterone, cortisone, 21-deoxycortisol; soluble urokinase plasminogen activator receptor, dehydroepiandrosterone sulfate, dihydrotestosterone, cortisol, and 11-deoxycorticosterone levels were lower. Analyzing these variables using a forward stepwise multivariate logistic regression model, we established a GDM prediction model with a specificity of 96.6% and sensitivity of 97.5% (included variables: fructosamine, cortisol, cortisone, 11-deoxycorticosterone, SuPAR). CONCLUSION: Based on these measurements, we accurately predict the development of later-onset GDM (24th-28th weeks of pregnancy). Early risk estimation provides the opportunity for targeted prevention and the timely treatment of GDM. Prevention and slowing the progression of GDM result in a lower lifelong metabolic risk for both mother and offspring.

Gastrodin protects endothelial cells against high glucose-induced injury through up-regulation of PPARß and alleviation of nitrative stress.

In diabetes mellitus (DM), high glucose can result in endothelial cell injury, and then lead to diabetic vascular complications. Gastrodin, as the mainly components of Chinese traditional herb Tianma (Gastrodia elata Bl.), has been widely used for cardiovascular diseases. However, the known of the effect of gastrodin on endothelial cell injury is still limited. In this study, we aimed to investigate the effect and possible mechanism of gastrodin on high glucose-injured human umbilical vein endothelial cells (HUVEC). High glucose (30 mmol/L) treatment caused HUVEC injury. After gastrodin (0.1, 1, 10 µmol/L) treatment, compared with the high glucose group, the cell proliferation ability increased in a dose-dependent manner. Meanwhile, gastrodin (10 µmol/L) up-regulated the mRNA and protein expressions of PPARß and eNOS, decreased the expressions of iNOS, also reduced the protein expression of 3-nitrotyrosine, and lowed the level of ONOO-, increased NO content. Both the PPARß antagonist GSK0660 (1 µmol/L) and the eNOS inhibitor L-NAME (10 µmol/L) were able to block the above effects of gastrodin. In conclusion, gastrodin protectes vascular endothelial cells from high glucose injury, which may be, at least partly, mediated by up-regulating the expression of PPARß and negatively regulating nitrative stress.

ALDH2 deficiency increases susceptibility to binge alcohol-induced gut leakiness, endotoxemia, and acute liver injury in mice through the gut-liver axis.

Mitochondrial aldehyde dehydrogenase 2 (ALDH2) is the major enzyme responsible for metabolizing toxic acetaldehyde to acetate and acts as a protective or defensive protein against various disease states associated with alcohol use disorder (AUD), including alcohol-related liver disease (ARLD). We hypothesized that Aldh2-knockout (KO) mice are more susceptible to binge alcohol-mediated liver injury than wild-type (WT) mice through increased oxidative stress, gut leakiness and endotoxemia. Therefore, this study aimed to investigate the protective role of ALDH2 in binge alcohol-induced gut permeability, endotoxemia, and acute inflammatory liver injury by exposing Aldh2-KO or WT mice to a single oral dose of binge alcohol 3.5, 4.0, or 5.0 g/kg. Our findings showed for the first time that ALDH2 deficiency in Aldh2-KO mice increases their sensitivity to binge alcohol-induced oxidative and nitrative stress, enterocyte apoptosis, and nitration of gut tight junction (TJ) and adherent junction (AJ) proteins, leading to their degradation. These resulted in gut leakiness and endotoxemia in Aldh2-KO mice after exposure to a single dose of ethanol even at 3.5 g/kg, while no changes were observed in the corresponding WT mice. The elevated serum endotoxin (lipopolysaccharide, LPS) and bacterial translocation contributed to systemic inflammation, hepatocyte apoptosis, and subsequently acute liver injury through the gut-liver axis. Treatment with Daidzin, an ALDH2 inhibitor, exacerbated ethanol-induced cell permeability and reduced TJ/AJ proteins in T84 human colon cells. These changes were reversed by Alda-1, an ALDH2 activator. Furthermore, CRISPR/Cas9-mediated knockout of ALDH2 in T84 cells increased alcohol-mediated cell damage and paracellular permeability. All these findings demonstrate the critical role of ALDH2 in alcohol-induced epithelial barrier dysfunction and suggest that ALDH2 deficiency or gene mutation in humans is a risk factor for alcohol-mediated gut and liver injury, and that ALDH2 could be an important therapeutic target against alcohol-associated tissue or organ damage.

Molecular and biochemical responses to tributyltin (TBT) exposure in the American oyster: Triggers of stress-induced oxidative DNA damage and prooxidant-antioxidant imbalance in tissues by TBT.

Environmental pollution increases due to anthropogenic activities. Toxic chemicals in the environment affect the health of aquatic organisms. Tributyltin (TBT) is a toxic chemical widely used as an antifouling paint on boats, hulls, and ships. The toxic effect of TBT is well documented in aquatic organisms; however, little is known about the effects of TBT on DNA lesions in shellfish. The American oyster (Crassostrea virginica, an edible and commercially important species) is an ideal marine mollusk to examine the effects of TBT exposure on DNA lesions and oxidative/nitrative stress. In this study, we investigated the effects of TBT on 8'-hydroxy-2'-deoxyguanosine (8-OHdG, a biomarker of pro-mutagenic DNA lesion), double-stranded DNA (dsDNA), dinitrophenyl protein (DNP, a biomarker on reactive oxygen species, ROS), 3-nitrotyrosine protein (NTP, a biomarker of reactive nitrogen species, RNS), catalase (CAT, an antioxidant), and acetylcholinesterase (AChE, a cholinergic enzyme) expressions in the gills and digestive glands of oysters. We also analyzed extrapallial (EF) fluid conditions. Immunohistochemical and qRT-PCR results showed that TBT exposure significantly increased 8-OHdG, dsDNA, DNP, NTP, and CAT mRNA and/or protein expressions in the gills and digestive glands. However, AChE mRNA and protein expressions, and EP fluid pH and protein concentrations were decreased in TBT-exposed oysters. Taken together, these results suggest that antifouling biocide-induced production of ROS/RNS results in DNA damage, which may lead to decreased cellular functions in oysters. To the best of our knowledge, the present study provides the first molecular/biochemical evidence that TBT exposure results in oxidative/nitrative stress and DNA lesions in oysters.

Oxidative/nitrosative stress increased the risk of recurrent pregnancy loss-Taiwan Recurrent Pregnancy Loss and Environmental Study (TREPLES).

OBJECTIVE: Oxidative stress biomarkers (OSBs) may be strongly associated with disease progression and recurrent pregnancy loss (RPL). However, the research on associations of most OSBs (e.g., 8-nitroguanine [8-NO2Gua] and 4-hydroxy-2-nonenal-mercapturic acid [HNE-MA]) with RPL is limited. Therefore, we aimed to investigate the effect of OSBs exposure on RPL risk by performing a case-control study. MATERIAL AND METHODS: We use our established dataset, Taiwan Recurrent Pregnancy Loss and Environmental Study (TREPLES), which included 514 Taiwanese reproductive age women (aged 20-50 years; 397 cases and 117 controls) from National Cheng Kung University Hospital. RPL is clinically defined by a history of two or more consecutive miscarriages, where a miscarriage is defined as the termination of pregnancy before 20 weeks of gestation. The urinary levels of several OSBs (e.g., 8-hydroxy-2'-deoxyguanosine [8-OHdG], 8-NO2Gua, 8-isoprostaglandin F2α [8-isoPGF2α], and HNE-MA) and malondialdehyde (MDA) were measured using isotope dilution liquid chromatography-tandem mass spectrometry and thiobarbituric acid reactive substances, respectively. RESULTS: The median levels of 8-NO2Gua (6.15 vs. 3.76 ng/mL) and HNE-MA (30.12 and 21.54 ng/mL) were significantly higher in the RPL group than in the control group. By categorizing the OSBs data into tertiles, after we adjusted for age and urine creatinine levels discovered that the RPL risk associated with 8-NO2Gua and HNE-MA levels in the third tertile were approximately 2 times higher than those in the first tertile (8-NO2Gua, adjusted OR = 3.27, 95 % CI = 1.66-6.43; HNE-MA, adjusted OR = 1.96, 95 % CI = 1.05-3.64; p < 0.05). These findings suggest that the oxidative stress biomarkers of 8-NO2Gua and HNE-MA are risk factors for RPL. CONCLUSION: Our findings indicate that specific OSBs are associated with an increased RPL risk, suggesting that reducing OSB levels can improve RPL risk. Nevertheless, more studies on preventive medicine are required to understand the exposure sources and adverse outcome pathways of OSBs associated with RPL.

Lead exposure induces nitrative stress and disrupts ribbon synapses in the cochlea.

Environmental exposure to heavy metal lead, a public health hazard in many post-industrial cities, causes hearing impairment upon long-term exposure. Lead-induced cochlear and vestibular dysfunction is well-documented in animal models. Although short-term exposure to lead at concentrations relevant to environmental settings does not cause significant shifts in hearing thresholds in adults, moderate- to low-level lead exposures induce neuronal damage and synaptic dysfunction. We reported that lead exposure induces oxidative stress in the mouse cochlea. However, lead-induced nitrative stress and potential damage to cochlear ribbon synapses are yet to be fully understood. Therefore, this study has evaluated cochlear synaptopathy and nitrative stress in young-adult mice exposed to 2 mM lead acetate for 28 days. Inductively coupled plasma mass spectrometry (ICP-MS) analysis indicated that this exposure significantly increased the blood lead levels. Assessment of hair cell loss by immunohistochemistry analysis and outer hair cell (OHC) activity by recording distortion product otoacoustic emissions (DPOAEs) indicated that the structure and function of the hair cells were not affected by lead exposure. However, this exposure significantly decreased the expression of C-terminal-binding protein-2 (CtBP2) and GluA2, pre- and post-synaptic protein markers in the inner hair cell synapses, particularly in the basal turn of the organ of Corti, suggesting lead-induced disruption of ribbon synapses. In addition, lead exposure significantly increased the nitrotyrosine levels in spiral ganglion cells, suggesting lead-induced nitrative stress in the cochlea. Collectively, these findings suggest that lead exposure even at levels that do not affect the OHCs induces cochlear nitrative stress and causes cochlear synaptopathy.

Nitrative Stress and Auditory Dysfunction.

Nitrative stress is increasingly recognized as a critical mediator of apoptotic cell death in many pathological conditions. The accumulation of nitric oxide along with superoxide radicals leads to the generation of peroxynitrite that can eventually result in the nitration of susceptible proteins. Nitrotyrosine is widely used as a biomarker of nitrative stress and indicates oxidative damage to proteins. Ototoxic insults, such as exposure to noise and ototoxic drugs, enhance the generation of 3-nitrotyrosine in different cell types in the cochlea. Nitrated proteins can disrupt critical signaling pathways and eventually lead to apoptosis and loss of sensory receptor cells in the cochlea. Accumulating evidence shows that selective targeting of nitrative stress attenuates cellular damage. Anti-nitrative compounds, such as peroxynitrite decomposition catalysts and inducible nitric oxide synthase inhibitors, prevent nitrative stress-mediated auditory damage. However, the role of nitrative stress in acquired hearing loss and its potential significance as a promising interventional target is yet to be fully characterized. This review provides an overview of nitrative stress mechanisms, the induction of nitrative stress in the auditory tissue after ototoxic insults, and the therapeutic value of targeting nitrative stress for mitigating auditory dysfunction.

Interactive effects of high temperature and pesticide exposure on oxidative status, apoptosis, and renin expression in kidney of goldfish: Molecular and cellular mechanisms of widespread kidney damage and renin attenuation.

One of many noteworthy consequences of increasing societal reliance on pesticides is their predominance in aquatic environments. These pernicious chemicals interact with high temperatures from global climate change, heat waves, and natural variations to create unstable environments that negatively impact organisms' health. To understand these conditions, we examined the dose-dependent effects of environmentally relevant pesticide mixtures (metolachlor, linuron, isoproturon, tebuconazole, aclonifen, atrazine, pendimethalin, and azinphos-methyl) combined with elevated temperatures (22 control vs. 32°C for 4-week exposure) on renin, dinitrophenyl protein (DNP, an indicator of reactive oxygen species, ROS), 3-nitrotyrosine protein (NTP, an indicator of reactive nitrogen species, RNS), superoxidase dismutase (SOD, an antioxidant), and catalase (CAT, an antioxidant) expressions in the kidneys of goldfish (Carassius auratus). Histopathological analysis showed widespread damage to kidney tissues in high temperature and pesticide co-exposure groups, including rupture of the epithelial layer, hemorrhaging, and degeneration of tubular epithelium. Quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemical analyses demonstrated significant declines in renin receptor-like mRNA and protein expressions in kidney tissues under combined exposure to high temperature and pesticides compared with controls; conversely, expression of DNP, NTP, SOD, and CAT increased in kidney tissues under the same conditions. Apoptotic cells were also increased in co-exposure groups as assessed by in situ terminal deoxynucleotidyl transferase dUTP nick labeling (TUNEL) assay. The enhanced apoptosis in kidneys of heat and pesticides co-exposed fish was associated with increased caspase-3 (a protease enzyme) mRNA levels. Our results demonstrated that high temperature and pesticides induced oxidative/nitrative stress (i.e., ROS/RNS), damaged tissues, increased cellular apoptosis, and suppressed renin expression in kidneys of goldfish.

Potential mechanisms of Na+/K+-ATPase attenuation by heat and pesticides co-exposure in goldfish: role of cellular apoptosis, oxidative/nitrative stress, and antioxidants in gills.

In this study, we examined the dose-dependent effects of an environmentally relevant pesticide cocktail (metalachlor, linuron, isoproturon, tebucanazole, aclonifen, atrazine, pendimethalin, and azinphos-methyl) and temperature change (22 vs. 32 °C for 4-week exposure) on Na+/K+-ATPase, 3-nitrotyrosine protein (NTP), dinitrophenyl protein (DNP), catalase (CAT), and superoxide dismutase (SOD) expressions in gills of goldfish (Carassius auratus). Histopathological analysis showed widespread damage to gill in elevated temperature (32 °C) and pesticide co-exposure groups, including fusion of secondary lamellae, club-shaped primary lamellae, rupture of epithelial layer, loss of normal architecture, and hemorrhaging. Immunohistochemical and qRT-PCR analyses showed significant decreases in Na+/K+-ATPase protein and mRNA expressions in gills exposed to higher temperature and pesticides; however, combined exposure to heat and pesticides significantly increases NTP, DNP, CAT, and SOD expressions. In situ TUNEL assay revealed elevated levels of apoptotic cells in response to combined exposure. Collectively, our results suggest the combined effects of heat and pesticide stress cause cellular damage, upregulate oxidative/nitrative stress biomarkers, and increase apoptotic cells, downregulate Na+/K+-ATPase expression in gills. This provides new evidence for oxidant/antioxidant-dependent mechanisms for downregulation of Na+/K+-ATPase expression in gills during combined exposure.

A preliminary evaluation of oxidative stress in patients with gastric cancer before chemotherapy.

Introduction: Due to an imbalanced redox status, cancer cells generate intrinsically higher levels of reactive oxygen species (ROS) compared to normal cells. Targeting ROS is an important therapeutic strategy for cancer as exemplified by cancer drugs, which induce ROS-dependent synergistic cytotoxicity in gastric cancer cells. The present study was designed to assess the level of selected oxidative stress biomarkers in blood plasma derived from gastric cancer patients. Material and methods: The study assessed the oxidative/nitrative biomarkers in blood plasma isolated from 51 gastric (adenocarcinoma) cancer patients, compared to a control group of 32 healthy volunteers. Oxidative stress was evaluated using a panel of biomarkers such as plasma protein thiol groups and 3-nitrotyrosine levels as well as indicators of plasma lipid peroxidation, i.e. lipid hydroperoxides (LOOH) and thiobarbituric acid-reactive substances (TBARS). Additionally, the total antioxidant capacity of blood plasma (non-enzymatic capacity of blood plasma, NEAC) was also estimated. Results: Our results showed that patients with gastric cancer had significantly different levels of thiol groups (lower, p < 0.001) and 3-nitrotyrosine (higher, p < 0.0001), LOOH (higher, p < 0.05), TBARS (higher, p < 0.05), NEAC (lower, p < 0.0001), compared to the control group. Conclusions: The present study indicates considerable oxidative/nitrative stress in gastric cancer patients. Our pilot study shows that not a single marker, but a biomarker panel, may be a more reliable representation of oxidative stress in patients with gastric cancer.

PPARß down-regulation is involved in high glucose-induced endothelial injury via acceleration of nitrative stress.

Endothelial injury plays a vital role in vascular lesions from diabetes mellitus (DM). Therapeutic targets against endothelial damage may provide critical venues for the treatment of diabetic vascular diseases. Peroxisome proliferator-activated receptor ß (PPARß) is a crucial regulator in DM and its complications. However, the molecular signal mediating the roles of PPARß in DM-induced endothelial dysfunction is not fully understood. The impaired endothelium-dependent relaxation and destruction of the endothelium structures appeared in high glucose incubated rat aortic rings. A high glucose level significantly decreased the expression of PPARß and endothelial nitric oxide synthase (eNOS) at the mRNA and protein levels, and reduced the concentration of nitric oxide (NO), which occurred in parallel with an increase in the expression of inducible nitric oxide synthase (iNOS) and 3-nitrotyrosine. The effect of high glucose was inhibited by GW0742, a PPARß agonist. Both GSK0660 (PPARß antagonist) and NG-nitro-l-arginine-methyl ester (NOS inhibitor) could reverse the protective effects of GW0742. These results suggest that the activation of nitrative stress may, at least in part, mediate the down-regulation of PPARß in high glucose-impaired endothelial function in rat aorta. PPARß-nitrative stress may hold potential in treating vascular complications from DM.