The oxidative stress theory of disease: levels of evidence and epistemological aspects

The Role of Oxidative Stress in Hypertension: The Insight into Antihypertensive Properties of Vitamins A, C and E

Hypertension stands as a pervasive global health challenge, contributing significantly to mortality rates worldwide. Various factors, including lifestyle choices and dietary habits, contribute to the development of hypertension. In recent years, oxidative stress has garnered significant attention as a factor influencing hypertension risk, prompting a shift in research focus towards exploring it as a potential target for prevention and treatment. Antioxidants found in our diet, such as vitamins C, E and carotenoids exhibit the ability to neutralize reactive oxygen species, thereby mitigating oxidative stress. In addition, Vitamin A has an antioxidant effect despite not being an antioxidant itself. Consequently, supplementation or increased intake of these antioxidants has been hypothesized to potentially lower blood pressure levels and aid in the management of hypertension, thereby potentially prolonging life expectancy. Research findings regarding this effect have been diverse. This paper examines the existing literature demonstrating favorable outcomes associated with antioxidant supplementation.

Exhaled VOC detection in lung cancer screening: a comprehensive meta-analysis

BACKGROUND

Lung cancer (LC), characterized by high incidence and mortality rates, presents a significant challenge in oncology. Despite advancements in treatments, early detection remains crucial for improving patient outcomes. The accuracy of screening for LC by detecting volatile organic compounds (VOCs) in exhaled breath remains to be determined.

METHODS

Our systematic review, following PRISMA guidelines and analyzing data from 25 studies up to October 1, 2023, evaluates the effectiveness of different techniques in detecting VOCs. We registered the review protocol with PROSPERO and performed a systematic search in PubMed, EMBASE and Web of Science. Reviewers screened the studies' titles/abstracts and full texts, and used QUADAS-2 tool for quality assessment. Then performed meta-analysis by adopting a bivariate model for sensitivity and specificity.

RESULTS

This study explores the potential of VOCs in exhaled breath as biomarkers for LC screening, offering a non-invasive alternative to traditional methods. In all studies, exhaled VOCs discriminated LC from controls. The meta-analysis indicates an integrated sensitivity and specificity of 85% and 86%, respectively, with an AUC of 0.93 for VOC detection. We also conducted a systematic analysis of the source of the substance with the highest frequency of occurrence in the tested compounds. Despite the promising results, variability in study quality and methodological challenges highlight the need for further research.

CONCLUSION

This review emphasizes the potential of VOC analysis as a cost-effective, non-invasive screening tool for early LC detection, which could significantly improve patient management and survival rates.

Inter-continental variability in the relationship of oxidative potential and cytotoxicity with PM2.5 mass

Most fine ambient particulate matter (PM2.5)-based epidemiological models use globalized concentration-response (CR) functions assuming that the toxicity of PM2.5 is solely mass-dependent without considering its chemical composition. Although oxidative potential (OP) has emerged as an alternate metric of PM2.5 toxicity, the association between PM2.5 mass and OP on a large spatial extent has not been investigated. In this study, we evaluate this relationship using 385 PM2.5 samples collected from 14 different sites across 4 different continents and using 5 different OP (and cytotoxicity) endpoints. Our results show that the relationship between PM2.5 mass vs. OP (and cytotoxicity) is largely non-linear due to significant differences in the intrinsic toxicity, resulting from a spatially heterogeneous chemical composition of PM2.5. These results emphasize the need to develop localized CR functions incorporating other measures of PM2.5 properties (e.g., OP) to better predict the PM2.5-attributed health burdens.

Superoxidase dismutases (SODs) in the European eel: Gene characterization, expression response to temperature combined with hormonal maturation and possible migratory implications

Superoxide dismutases (SODs) are antioxidant enzymes that protect cells from oxidation. Three SODs have been identified in mammals, but there is limited information in teleosts. This study investigates SODs in the European eel and their expression patterns during testis maturation. Phylogenetic and synteny analyses revealed SODs paralogs and their evolution in vertebrates. The eel possesses one SOD1 and two SOD2/3 (a and b), indicating SOD2 and SOD3 duplication in elopomorphs. SODs expression were then evaluated in various male and female tissues. SOD1 is more expressed in females, while SOD2a and SOD2b dominate brain-pituitary-gonad tissues in both sexes. SOD3a showed predominant expression in the ovary and the male livers, whereas SOD3b was found in the pituitary and brain of both sexes. The effects of different maturation protocols (standard hormonal treatment vs. same protocol preceded with cold seawater pre-treatment) on SODs expression during testis maturation were evaluated. Salinity increase at the onset of standard treatment at 20 °C, simulating early migration, upregulated SOD1, SOD2a, and SOD2b, coinciding with spermatogonia type A differentiated cells dominance. Thereafter, SOD2a and SOD3a decreased, while SOD2b increased during hormonal treatment-induced spermatogenesis. Pre-treatment with seawater at 10 °C, mimicking the conditions at the beginning of the seawater migration, downregulated SOD1 but increased SOD3a expression. Finally, the standard hormonal treatment, replicating spawning at higher temperatures, downregulated SOD1 in eels without any pre-treatment while SOD2a expression increased in pre-treated eels. This study revealed tissue-specific, sex-dependent, and maturation-related SOD expression patterns, predicting SODs dynamic expression profiles during their reproductive migration.

In Vitro Evaluation of the Antioxidant Capacity of 3,3-Disubstituted-3H-benzofuran-2-one Derivatives in a Cellular Model of Neurodegeneration

Oxidative stress represents a hallmark for many degenerative pathologies of the Central Nervous System. Throughout life, the constant pressure of noxious stimuli and/or episodes of traumatic events may expose the brain to a microenvironment where the non-balanced reactive oxygen species inevitably lead to neuronal loss and cognitive decline. HO-1, a 32 kDa heat-shock protein catalyzing the degradation of heme into carbon monoxide (CO), iron and biliverdin/bilirubin is considered one of the main antioxidant defense mechanisms playing pivotal roles in neuroprotection. Restoring the redox homeostasis is the goal of many natural or synthetic antioxidant molecules pursuing beneficial effects on brain functions. Here, we investigated the antioxidant capacity of four selected benzofuran-2-one derivatives in a cellular model of neurodegeneration represented by differentiated SH-SY5Y cells exposed to catechol-induced oxidative stress. Our main results highlight how all the molecules have antioxidant properties, especially compound 9, showing great abilities in reducing intracellular ROS levels and protecting differentiated SH-SY5Y cells from catechol-induced death. This compound above all seems to boost HO-1 mRNA and perinuclear HO-1 protein isoform expression when cells are exposed to the oxidative insult. Our findings open the way to consider benzofuran-2-ones as a novel and promising adjuvant antioxidant strategy for many neurodegenerative disorders.

Dexamethasone Induced Osteocyte Apoptosis in Steroid-Induced Femoral Head Osteonecrosis through ROS-Mediated Oxidative Stress

OBJECTIVE

Glucocorticoid (GC) overuse is strongly associated with steroid-induced osteonecrosis of the femoral head (SINFH). However, the underlying mechanism of SINFH remains unclear. This study aims to investigate the effect of dexamethasone (Dex)-induced oxidative stress on osteocyte apoptosis and the underlying mechanisms.

METHODS

Ten patients with SINFH and 10 patients with developmental dysplasia of the hips (DDH) were enrolled in our study. Sixty rats were randomly assigned to the Control, Dex, Dex + N-Acetyl-L-cysteine (NAC), Dex + Dibenziodolium chloride (DPI), NAC, and DPI groups. Magnetic resonance imaging (MRI) was used to examine edema in the femoral head of rats. Histopathological staining was performed to assess osteonecrosis. Immunofluorescence staining with TUNEL and 8-OHdG was conducted to evaluate osteocyte apoptosis and oxidative damage. Immunohistochemical staining was carried out to detect the expression of NOX1, NOX2, and NOX4. Viability and apoptosis of MLO-Y4 cells were measured using the CCK-8 assay and TUNEL staining. 8-OHdG staining was conducted to detect oxidative stress. 2',7'-Dichlorodihydrofluorescein diacetate (DCFH-DA) staining was performed to measure reactive oxygen species (ROS). The expression of NOX1, NOX2, and NOX4 in MLO-Y4 cells was analyzed by Western blotting. Multiple comparisons were performed using one-way analysis of variance (ANOVA).

RESULTS

In patients and the rat model, hematoxylin-eosin (HE) staining revealed a significantly higher rate of empty lacunae in the SINFH group than in the DDH group. Immunofluorescence staining indicated a significant increase in TUNEL-positive cells and 8-OHdG-positive cells in the SINFH group compared to the DDH group. Immunohistochemical staining demonstrated a significant increase in the expression of NOX1, NOX2, and NOX4 proteins in SINFH patients compared to DDH patients. Moreover, immunohistochemical staining showed a significant increase in the proportion of NOX2-positive cells compared to the Control group in the femoral head of rats. In vitro, Dex significantly inhibited the viability of osteocyte cells and induced apoptosis. After Dex treatment, the intracellular ROS level increased. However, Dex treatment did not alter the expression of NOX proteins in vitro. Additionally, NAC and DPI inhibited the generation of intracellular ROS and partially alleviated osteocyte apoptosis in vivo and in vitro.

CONCLUSION

This study demonstrates that GC promotes apoptosis of osteocyte cells through ROS-induced oxidative stress. Furthermore, we found that the increased expression of NOXs induced by GC serves as an important source of ROS generation.

The Role and Mechanism of Nicotinamide Riboside in Oxidative Damage and a Fibrosis Model of Trabecular Meshwork Cells

Purpose

To investigate the potential effects and mechanism of nicotinamide riboside (NR) on the oxidative stress and fibrosis model of human trabecular meshwork (HTM) cell line cells.

Methods

HTM cells were pretreated with NR, followed by the induction of oxidative injury and fibrosis by hydrogen peroxide (H2O2) and TGF-β2, respectively. Cell viability was tested using Hoechst staining and MTT assays, cell proliferation was assessed by EdU assay, and cell apoptosis was detected by flow cytometry and western blotting. DCFH-DA and DHE probes were used to measure the level of reactive oxygen species (ROS), and MitoTracker staining was used to measure the mitochondrial membrane potential (MMP). Fibrotic responses, including cell migration and deposition of extracellular matrix (ECM) proteins, were detected via Transwell assays, qRT-PCR, and immunoblotting.

Results

NR pretreatment improved the viability, proliferation, and MMP of H2O2-treated HTM cells. Compared to cells treated solely with H2O2, HTM cells treated with both NR and H2O2, exhibited a reduced rate of apoptosis and generation of ROS. Compared with H2O2 pretreatment, NR pretreatment upregulated expression of the JAK2/Stat3 pathway but inhibited mitogen-activated protein kinase (MAPK) pathway expression. Moreover, 10-ng/mL TGF-β2 promoted cell proliferation and migration, which were inhibited by NR pretreatment. Both qRT-PCR and immunoblotting showed that NR inhibited the expression of fibronectin in a TGF-β2-induced fibrosis model.

Conclusions

NR has a protective effect on oxidative stress and fibrosis in HTM cells, which may be related to the JAK2/Stat3 pathway and MAPK pathway.

Translational Relevance

Our research provides the ongoing data for potential therapy of NAD+ precursors in glaucoma.

Use of immunology in news and YouTube videos in the context of COVID-19: politicisation and information bubbles

Background

The COVID-19 pandemic propelled immunology into global news and social media, resulting in the potential for misinterpreting and misusing complex scientific concepts.

Objective

To study the extent to which immunology is discussed in news articles and YouTube videos in English and Italian, and if related scientific concepts are used to support specific political or ideological narratives in the context of COVID-19.

Methods

In English and Italian we searched the period 11/09/2019 to 11/09/2022 on YouTube, using the software Mozdeh, for videos mentioning COVID-19 and one of nine immunological concepts: antibody-dependent enhancement, anergy, cytokine storm, herd immunity, hygiene hypothesis, immunity debt, original antigenic sin, oxidative stress and viral interference. We repeated this using MediaCloud for news articles.Four samples of 200 articles/videos were obtained from the randomised data gathered and analysed for mentions of concepts, stance on vaccines, masks, lockdown, social distancing, and political signifiers.

Results

Vaccine-negative information was higher in videos than news (8-fold in English, 6-fold in Italian) and higher in Italian than English (4-fold in news, 3-fold in videos). We also observed the existence of information bubbles, where a negative stance towards one intervention was associated with a negative stance to other linked ideas. Some immunological concepts (immunity debt, viral interference, anergy and original antigenic sin) were associated with anti-vaccine or anti-NPI (non-pharmacological intervention) views. Videos in English mentioned politics more frequently than those in Italian and, in all media and languages, politics was more frequently mentioned in anti-guidelines and anti-vaccine media by a factor of 3 in video and of 3-5 in news.

Conclusion

There is evidence that some immunological concepts are used to provide credibility to specific narratives and ideological views. The existence of information bubbles supports the concept of the "rabbit hole" effect, where interest in unconventional views/media leads to ever more extreme algorithmic recommendations.

Dietary (poly)phenols and cardiometabolic health: from antioxidants to modulators of the gut microbiota

(Poly)phenols are plant secondary metabolites widely abundant in plant foods and beverages comprising a very large number of compounds with diverse structure and biological activities. Accumulating evidence indicates that these compounds exert beneficial effects against cardiometabolic diseases, and this review will provide a summary of current knowledge in this area. Epidemiological and clinical data collectively suggest that intake of flavonoids reduces the risk of cardiovascular disease (CVD), with the evidence being particularly strong for the flavan-3-ol subclass. However, to provide adequate dietary recommendations, a better understanding of their estimated content in foods and intake among the general public is needed. Regarding mechanisms of action, we now know that it is unlikely that (poly)phenols act as direct antioxidants in vivo, as it was hypothesised for decades with the popularity of in vitro antioxidant capacity assays. One of the reasons is that upon ingestion, (poly)phenols are extensively metabolised into a wide array of circulating metabolites with different bioactivities than their precursors. Well-conducted in vitro and in vivo studies and human nutrigenomic analysis have revealed new molecular targets that may be underlying the health benefits of (poly)phenols, such as the nitric oxide pathway. Recently, a bi-directional relationship was established between (poly)phenols and the gut microbiota, suggesting that individual gut microbial metabolising capacity may be a key factor explaining the variability in the cardiometabolic response to (poly)phenols. Future research is needed to elucidate which are the key factors affecting such capacity, and whether it can be modulated, along with the mechanisms of action.

A Critical Appraisal of the Protective Activity of Polyphenolic Antioxidants against Iatrogenic Effects of Anticancer Chemotherapeutics

Polyphenolic compounds, encompassing flavonoids (e.g., quercetin, rutin, and cyanidin) and non-flavonoids (e.g., gallic acid, resveratrol, and curcumin), show several health-related beneficial effects, which include antioxidant, anti-inflammatory, hepatoprotective, antiviral, and anticarcinogenic properties, as well as the prevention of coronary heart diseases. Polyphenols have also been investigated for their counteraction against the adverse effects of common anticancer chemotherapeutics. This review evaluates the outcomes of clinical studies (and related preclinical data) over the last ten years, with a focus on the use of polyphenols in chemotherapy as auxiliary agents acting against oxidative stress toxicity induced by antitumor drugs. While further clinical studies are needed to establish adequate doses and optimal delivery systems, the improvement in polyphenols' metabolic stability and bioavailability, through the implementation of nanotechnologies that are currently being investigated, could improve therapeutic applications of their pharmaceutical or nutraceutical preparations in tumor chemotherapy.

Reactive oxygen species downregulate dystroglycans in the megakaryocytes of rats with arterial hypertension

Hypertension is a multifactorial disease characterized by vascular and renal dysfunction, cardiovascular remodeling, inflammation, and fibrosis, all of which are associated with oxidative stress. We previously demonstrated cellular reactive oxygen species (ROS) imbalances may impact the structural and biochemical functions of blood cells and reported downregulation of β-dystroglycan (β-Dg) and overexpression of the epithelial sodium channel (ENaC) contribute to the pathophysiology of hypertension. In this study, we aimed to determine the expression of dystroglycans (Dg) and ENaC in platelet progenitors (megakaryocytes) and their surrounding niches. Thin sections of bone marrow from 5- and 28-week-old spontaneous hypertensive rats (SHR) were compared to age-matched normotensive rats (WKY). Cytometry and immunohistochemical assays demonstrated an oxidative environment in SHR bone marrow, characterized by high levels of myeloperoxidase and 3-nitrotyrosine and downregulation of peroxiredoxin II. In addition, transmission electron micrography and confocal microscopy revealed morphological changes in platelets and Mgks from SHR rats, including swollen mitochondria. Quantitative qRT-PCR assays confirmed downregulation of Dg mRNA and immunohistochemistry and western-blotting validated low expression of β-Dg, mainly in the phosphorylated form, in Mgks from 28-week-old SHR rats. Moreover, we observed a progressive increase in β-1 integrin expression in Mgks and extracellular matrix proteins in Mgk niches in SHR rats compared to WKY controls. These results indicate accumulation of ROS promotes oxidative stress within the bone marrow environment and detrimentally affects cellular homeostasis in hypertensive individuals.

Dose-response effect of a recreational team handball-based exercise programme on cardiometabolic health and physical fitness in inactive middle-aged-to-elderly males - a randomised controlled trial

This study aimed at examining the dose-response of a recreational team handball (TH) exercise-based programme on cardiometabolic health and physical fitness in inactive middle-aged-to-elderly males without TH experience. Fifty-four inactive middle-aged-to-elderly men (67.5 ± 4.2 years; stature 168.8 ± 6.2 cm; body mass 78.4 ± 10.7 kg; fat mass 27.1 ± 5.3%; BMI 27.4 ± 2.9 kg/m2; VO2peak 27.3 ± 4.8 mL/min/kg) were randomised into three intervention groups performing 1 (TH1, n = 13), 2 (TH2, n = 15), or 3 (TH3, n = 12) 60-min weekly recreational TH-based training sessions, for 16 weeks, and a control group (CG, n = 14). A time x group interaction was observed for VO2peak, aerobic performance, fasting plasma insulin and body and fat mass (p ≤ 0.043) with TH3 showing the greatest overall effects. Post-intervention differences were observed in aerobic performance (TH3>CG, TH1 and TH2; TH2>CG), body mass (TH3>CG and TH1), fat mass (TH3>CG), VO2peak (TH3>CG) and plasma insulin (TH3>CG) (p ≤ 0.040). In conclusion, recreational TH performed for 60-min thrice and twice per week results in improved aerobic performance for middle-aged-to-elderly men. Moreover, it was observed that three weekly sessions were more effective in providing overall cardiometabolic benefits compared to training with a lower weekly frequency. ClinicalTrials.gov ID: NCT05295511.Trial registration: ClinicalTrials.gov identifier: NCT05295511.Highlights: We observed high intensities and fun levels during recreational TH, organised as formal and small-sided games, for middle-aged-to-elderly men during a 16-week period, independently of the number of weekly training sessions.Marked positive effects on aerobic performance and cardiometabolic health were observed in the intervention group that performed 3 weekly sessions.The study results indicate that recreational TH training with low frequency and volume results in some beneficial effects on cardiometabolic fitness and health for middle-aged-to-elderly men, but future studies with more participants or longer intervention periods are warranted to explore this possibility.

Vitamin E Treatment Improves the Antioxidant Capacity of Patients Receiving Dialysis: A Systematic Review and Meta-Analysis

SCOPE

To summarize the effect of vitamin E-coated dialyzer membranes (VEMs) treatment or oral vitamin E intake on antioxidant molecules, such as superoxide dismutase (SOD), glutathione peroxidase (GPX), catalase (CAT), and total antioxidant level in patients receiving dialysis.

METHODS AND RESULTS

A literature search of PubMed, Embase, CNKI, and the Cochrane Library databases is performed from inception to July 1, 2023, with no language nor country restrictions. Twenty-four experimental studies involving 512 patients undergoing dialysis are selected for meta-analysis. The levels of antioxidant markers in the blood of patients receiving hemodialysis (HD) improve with long-term VEMs treatment (p = 0.016). According to the findings of each antioxidant index, there is a significant increase in the levels of erythrocyte-derived SOD (p = 0.047), CAT (p = 0.029), and plasma-derived total antioxidant level (p < 0.001). The antioxidant marker levels in patients receiving HD are significantly increased by oral vitamin E intake (p < 0.001). Erythrocyte-derived SOD (p = 0.003), GPX (p < 0.001), and CAT (p = 0.001) substantially improves after 2-6 months of intervention with oral vitamin E preparation. The antioxidant index of patients receiving peritoneal dialysis (PD) is unaffected by oral vitamin E treatment (p = 0.945).

CONCLUSION

Vitamin E therapy has a favorable effect on the retention of antioxidant compounds in patients undergoing dialysis.

Neuroprotective Effects of Phenolic Antioxidant Tert-butylhydroquinone (tBHQ) in Brain Diseases

Human life and health are gravely threatened by brain diseases. The onset and progression of the illnesses are influenced by a variety of factors, including pathogenic causes, environmental factors, mental issues, etc. According to scientific studies, neuroinflammation and oxidative stress play a significant role in the development and incidence of brain diseases by producing pro-inflammatory cytokines and oxidative tissue damage to induce inflammation and apoptosis. Neuroinflammation, oxidative stress, and oxidative stress-related changes are inseparable factors in the etiology of several brain diseases. Numerous neurodegenerative diseases have undergone substantial research into the therapeutic alternatives that target oxidative stress, the function of oxidative stress, and the possible therapeutic use of antioxidants. Formerly, tBHQ is a synthetic phenolic antioxidant, which has been widely used as a food additive. According to recent researches, tBHQ can suppress the processes that lead to neuroinflammation and oxidative stress, which offers a fresh approach to treating brain diseases. In order to achieve the goal of decreasing inflammation and apoptosis, tBHQ is a specialized nuclear factor erythroid 2-related factor (Nrf2) activator that decreases oxidative stress and enhances antioxidant status by upregulating the Nrf2 gene and reducing nuclear factor kappa-B (NF-κB) activity. This article reviews the effects of tBHQ on neuroinflammation and oxidative stress in recent years and looks into how tBHQ inhibits neuroinflammation and oxidative stress through human, animal, and cell experiments to play a neuroprotective role in Alzheimer's disease (AD), stroke, depression, and Parkinson's disease (PD). It is anticipated that this article will be useful as a reference for upcoming research and the creation of drugs to treat brain diseases.

Oxidative Stress Is a Concept, Not an Indication for Selective Antioxidant Treatment

The steady-state redox status is physiologically important and therefore homeostatically maintained. Changes in the status result in signaling (eustress) or oxidative damage (distress). Oxidative stress (OS) is a hard-to-quantitate term that can be estimated only based on different biomarkers. Clinical application of OS, particularly for selective antioxidant treatment of people under oxidative stress, requires quantitative evaluation and is limited by the lack of universal biomarkers to describe it. Furthermore, different antioxidants have different effects on the redox state. Hence, as long as we do not have the possibility to determine and quantify OS, therapeutic interventions by the "identify-and-treat" approach cannot be assessed and are, therefore, not likely to be the basis for selective preventive measures against oxidative damage.

Redox-Mechanisms of Molecular Hydrogen Promote Healthful Longevity

Age-related diseases represent the largest threat to public health. Aging is a degenerative, systemic, multifactorial and progressive process, coupled with progressive loss of function and eventually leading to high mortality rates. Excessive levels of both pro- and anti-oxidant species qualify as oxidative stress (OS) and result in damage to molecules and cells. OS plays a crucial role in the development of age-related diseases. In fact, damage due to oxidation depends strongly on the inherited or acquired defects of the redox-mediated enzymes. Molecular hydrogen (H2) has recently been reported to function as an anti-oxidant and anti-inflammatory agent for the treatment of several oxidative stress and aging-related diseases, including Alzheimer's, Parkinson's, cancer and osteoporosis. Additionally, H2 promotes healthy aging, increases the number of good germs in the intestine that produce more intestinal hydrogen and reduces oxidative stress through its anti-oxidant and anti-inflammatory activities. This review focuses on the therapeutic role of H2 in the treatment of neurological diseases. This review manuscript would be useful in knowing the role of H2 in the redox mechanisms for promoting healthful longevity.

Oxidative Stress, Antioxidants and Hypertension

As a major cause of morbidity and mortality globally, hypertension remains a serious threat to global public health. Despite the availability of many antihypertensive medications, several hypertensive individuals are resistant to standard treatments, and are unable to control their blood pressure. Regulation of the renin-angiotensin-aldosterone system (RAAS) controlling blood pressure, activation of the immune system triggering inflammation and production of reactive oxygen species, leading to oxidative stress and redox-sensitive signaling, have been implicated in the pathogenesis of hypertension. Thus, besides standard antihypertensive medications, which lower arterial pressure, antioxidant medications were tested to improve antihypertensive treatment. We review and discuss the role of oxidative stress in the pathophysiology of hypertension and the potential use of antioxidants in the management of hypertension and its associated organ damage.

The Emerging Role of Salivary Oxidative Stress Biomarkers as Prognostic Markers of Periodontitis: New Insights for a Personalized Approach in Dentistry

Periodontitis is a multifactorial and infective oral disease that leads to the destruction of periodontal tissues and tooth loss. Although the treatment of periodontitis has improved recently, the effective treatment of periodontitis and the periodontitis-affected periodontal tissues is still a challenge. Therefore, exploring new therapeutic strategies for a personalized approach is urgent. For this reason, the aim of this study is to summarize recent advances and the potential of oxidative stress biomarkers in the early diagnosis and personalized therapeutic approaches in periodontitis. Recently, ROS metabolisms (ROMs) have been studied in the physiopathology of periodontitis. Different studies show that ROS plays a crucial role in periodontitis. In this regard, the reactive oxygen metabolites (ROMs) started to be searched for the measures of the oxidizing capacity of the plasma understood as the total content of oxygen free radicals (ROS). The oxidizing capacity of plasma is a significant indicator of the body's oxidant state as well as homocysteine (Hcy), sulfur amino acid, which has pro-oxidant effects as it favors the production of superoxide anion. More specifically, the thioredoxin (TRX) and peroxiredoxin (PRX) systems control reactive oxygen species (ROS), such as superoxide and hydroxyl species, to transduce redox signals and change the activities of antioxidant enzymes to remove free radicals. Superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPx), among other antioxidant enzymes, change their activity when ROS are produced in order to neutralize free radicals. The TRX system is triggered and transduces redox signals to do this.

Oxidative Stress and Its Relation to Lower Urinary Tract Symptoms

The aim of this review is to discuss how to link lower urinary tract symptoms (LUTS) and oxidative stress (OS) and to define relevant targets for therapeutic intervention. Narrative review based on published literature. Many of the multifactorial pathophysiological mechanisms behind LUTS can initiate reactive oxygen species (ROS) generation. Assuming that OS is a consequence rather than a primary cause of LUTS it seems reasonable to identify both the disease mechanism initiating LUTS, and the source of ROS involved. There are many possible sources of ROS overproduction, but the NADPH oxidase (NOX) family of enzymes is the primary source; NOX activation in turn, may result in the activation of secondary ROS sources, i.e., ROS-dependent ROS production. Selective NOX inhibition therefore seems an attractive therapeutic strategy in LUTS treatment. The finding of NOX2 localization to centers in the brain associated with micturition control, opens up for further studies of NOX involvement in the central control of micturition, normally and in disease. Further information on the localization of the different isoforms of NOX in the LUT e.g., the bladder wall and its components and the prostate, is desirable. To optimize treatment, the pathophysiological mechanism initiating LUTS, and the activated isoform of NOX, should be identified. Unfortunately, in most cases of LUTS this is currently not possible. Even if selective NOX inhibitors have entered the clinical trial stage for treatment of disorders other than LUT dysfunction, their efficacy for LUTS treatment has to be demonstrated. If this can be achieved, an attractive approach would be combination of selective NOX inhibition with established drug therapies.

Salivary Biomarkers in Periodontitis Post Scaling and Root Planing

OBJECTIVES

This study was conducted to evaluate the levels of salivary uric acid and arginase in patients with periodontitis, generalized gingivitis, and in healthy individuals. Then, the effects of non-surgical periodontal therapy on levels of salivary arginase and uric acid were also investigated.

METHODS

A total of 60 subjects were divided into three groups based on periodontal health: group I comprised 20 healthy individuals; group II comprised 20 subjects who had generalized gingivitis; group III comprised 20 subjects who had generalized periodontitis. On day 0, the clinical examination of periodontal status was recorded, following which saliva samples were collected. Group II and group III subjects underwent non-surgical periodontal therapy. These patients were recalled on day 30 to collect saliva samples. The periodontal parameters were reassessed on day 90, and saliva samples were collected for analysis of salivary arginase and uric acid levels.

RESULTS

Group II and group III showed improvement in clinical parameters following non-surgical periodontal therapy on the 90th day. The MGI score, PPD, and CAL showed improvement. On day 0, at baseline, salivary arginase levels in group III and group II were higher than those in healthy subjects, whereas on day 0, salivary uric acid levels in group III and group II were lower than those in healthy subjects. Both on day 0 and day 90, the salivary arginase level showed a positive correlation with the periodontal parameters, whereas the salivary uric acid level was positively correlated with the periodontal parameters on day 90.

CONCLUSION

the level of salivary arginase was a pro-inflammatory marker and a raised level of salivary uric acid was an anti-inflammatory marker following periodontal therapy, suggesting their pivotal role in assessing periodontal status and evaluation of treatment outcome.

P66Shc (Shc1) Zebrafish Mutant Line as a Platform for Testing Decreased Reactive Oxygen Species in Pathology

Reactive oxygen species (ROS) dysregulation exacerbates many pathologies but must remain within normal ranges to maintain cell function. Since ROS-mediated pathology and routine cell function are coupled, in vivo models evaluating low-ROS background effects on pathology are limited. Some models alter enzymatic antioxidant expression/activity, while others involve small molecule antioxidant administration. These models cause non-specific ROS neutralization, decreasing both beneficial and detrimental ROS. This is detrimental in cardiovascular pathology, despite the negative effects excessive ROS has on these pathologies. Thus, current trends in ROS-mediated pathology have shifted toward selective inhibition of ROS producers that are dysregulated during pathological insults, such as p66Shc. In this study, we evaluated a zebrafish heterozygote p66Shc hypomorphic mutant line as a low-ROS myocardial infarction (MI) pathology model that mimics mammalian MI. Our findings suggest this zebrafish line does not have an associated negative phenotype, but has decreased body mass and tissue ROS levels that confer protection against ROS-mediated pathology. Therefore, this line may provide a low-ROS background leading to new insights into disease.

DPP3: From biomarker to therapeutic target of cardiovascular diseases

Cardiovascular disease is the leading cause of death globally among non-communicable diseases, which imposes a serious socioeconomic burden on patients and the healthcare system. Therefore, finding new strategies for preventing and treating cardiovascular diseases is of great significance in reducing the number of deaths and disabilities worldwide. Dipeptidyl peptidase 3 (DPP3) is the first zinc-dependent peptidase found among DPPs, mainly distributes within the cytoplasm. With the unique HEXXGH catalytic sequence, it is associated with the degradation of oligopeptides with 4 to 10 amino acids residues. Accumulating evidences have demonstrated that DPP3 plays a significant role in almost all cellular activities and pathophysiological mechanisms. Regarding the role of DPP3 in cardiovascular diseases, it is currently mainly used as a biomarker for poor prognosis in patients with cardiovascular diseases, suggesting that the level of DPP3 concentration in plasma is closely linked to the mortality of diseases such as cardiogenic shock and heart failure. Interestingly, it has been reported recently that DPP3 regulates blood pressure by interacting with the renin-angiotensin system. In addition, DPP3 also participates in the processes of pain signaling, inflammation, and oxidative stress. But the exact mechanism by which DPP3 affects cardiovascular function is not clear. Hence, this review summarizes the recent advances in the structure and catalytic activity of DPP3 and its extensive biological functions, especially its role as a therapeutic target in cardiovascular diseases. It will provide a theoretical basis for exploring the potential value of DPP3 as a therapeutic target for cardiovascular diseases.

Gardeniae Fructus Extract Alleviates Dexamethasone-Induced Muscle Atrophy in Mice

Muscle atrophy (MA) is a case in which protein degeneration occurs excessively due to an imbalance between protein synthesis and breakdown, and is characterized by decreased muscle mass and weakened muscle strength. Despite mounting concern about MA, the number of patients with MA is increasing every year. The aim of the present study was to assess the impact of Gardeniae Fructus (GF) hot water extract on dexamethasone (DEX)-induced MA in mice. C57BL/6N mice were grouped (n = 8) as follows: Normal mice (Normal), MA mice were treated with distilled water (Control), MA mice were treated with GF 100 mg/kg (GF100), MA mice were treated with GF 200 mg/kg (GF200). For 10 days, DEX (25 mg/kg body weight, i.p.) injection was used to induce MA, and GF was administered. GF treatment restored the muscle weight decreased due to MA, and in particular, the weights of EDL+TA and Sol were significantly increased in the GF200 group. Also, it was confirmed that the swimming time was improved in the GF200 group. In addition, the expression of NADPH oxidase related to oxidative stress was significantly reduced, and protective (insulin-like growth factor I/phosphoinositide 3-kinase/protein kinase B pathway) and catabolic (AMP-activated kinase [AMPK]/sirtuin 1 [SIRT1]/proliferator-activated receptor-gamma coactivator-1α (PGC-1α)-forkhead box O (FOXO) pathway) pathways were significantly modulated. These results demonstrate that GF regulates muscle protein synthesis and catabolic pathways, and in particular, it is judged to improve MA by regulating the proteolytic AMPK/SIRT1/PGC-1α-FOXO pathway.

Oxidative Stress Biomarkers in the Diagnosis and Prognosis

Oxidative stress describes the state of a cell where there is an imbalance between free radical formation and antioxidants due to either excess formation of reactive oxygen species (ROS) or inadequate antioxidant defence. It is very well known that oxidative stress plays an important role in the pathophysiology of various diseases through impaired intracellular redox homeostasis. To evaluate and imply the excess production of ROS, various biomarkers are used and suggested, yet it is also known that there is a lack of standardization and validation for these methods. It is almost very difficult to measure ROS directly because of their short half-life, yet it is still possible with a suitable technique. The most frequently used biomarkers are represented by oxidized macromolecules such as lipids, proteins, and nucleic acids, which are modified via ROS, and also the amounts or activities of antioxidant molecules and enzymes, respectively. There are also various genetic biomarkers measuring the susceptibility of modification due to oxidative stress. However, the preferred biomarker would be dependent on the aim of the study and the clinical relevance.

Inhibition of activity/expression, or genetic deletion, of ERO1α blunts arsenite geno- and cyto-toxicity

Our recent studies suggest that arsenite stimulates the crosstalk between the inositol 1, 4, 5-triphosphate receptor (IP₃R) and the ryanodine receptor (RyR) via a mechanism dependent on endoplasmic reticulum (ER) oxidoreductin1α (ERO1α) up-regulation. Under these conditions, the fraction of Ca²⁺ released by the RyR via an ERO1α-dependent mechanism was promptly cleared by the mitochondria and critically mediated O₂^-. formation, responsible for the triggering of time-dependent events associated with strand scission of genomic DNA and delayed mitochondrial apoptosis. We herein report that, in differentiated C2C12 cells, this sequence of events can be intercepted by genetic deletion of ERO1α as well as by EN460, an inhibitor of ERO1α activity. Similar results were obtained for the early effects mediated by arsenite in proliferating U937 cells, in which however the long-term studies were hampered by the intrinsic toxicity of the inhibitor. It was then interesting to observe that ISRIB, an inhibitor of p-eIF2 alpha, was in both cell types devoid of intrinsic toxicity and able to suppress ERO1α expression and the resulting downstream effects leading to arsenite geno- and cyto-toxicity. We therefore conclude that pharmacological inhibition of ERO1α activity, or expression, effectively counteracts the deleterious effects induced by the metalloid via a mechanism associated with prevention of mitochondrial O₂^-. formation.

A randomized control trial of high-dose micronutrient-antioxidant supplementation in healthy persons with untreated HIV infection

Background

Although micronutrient and antioxidant supplementation are widely used by persons with human immunodeficiency virus (HIV), a therapeutic role beyond recommended daily allowances (RDA) remains unproven. An oral high-dose micronutrient and antioxidant supplement (Treatment) was compared to an RDA supplement (Control) for time to progressive immunodeficiency or initiation of antiretroviral therapy (ART) in people living with HIV (PLWH).

Methods

This study was a randomized, double-blind, placebo-controlled multicenter clinical trial. PLWH were recruited from Canadian HIV Trials Network sites, and followed quarterly for two years. Eligible participants were asymptomatic, antiretroviral treatment (ART)-naïve, HIV-seropositive adults with a CD4 T lymphocyte count (CD4 count) between 375–750 cells/μL. Participants were randomly allocated 1:1 to receive Treatment or Control supplements. The primary outcome was a composite of time-to-first of confirmed CD4 count below 350 cells/μL, initiation of ART, AIDS-defining illness or death. Primary analysis was by intention-to-treat. Secondary outcomes included CD4 count trajectory from baseline to ART initiation or two years. A Data and Safety Monitoring Board reviewed the study for safety, recruitment and protocol adherence every six months.

Results

Of 171 enrolled participants: 66 (38.6%) experienced a primary outcome: 27 reached a CD4 count below 350 cells/μL, and 57 started ART. There was no significant difference in time-to-first outcome between groups (Hazard Ratio = 1.05; 95%CI: 0.65, 1.70), or in time to any component outcome. Using intent-to-treat censoring, mean annualized rates of CD4 count decline were -42.703 cells/μL and -79.763 cells/μL for Treatment and Control groups, with no statistical difference in the mean change between groups (-37.06 cells/μL/52 weeks, 95%CI: (-93.59, 19.47); p = 0.1993). Accrual was stopped at 171 of the 212 intended participants after an interim analysis for futility, although participant follow-up was completed.

Conclusions

In ART-naïve PLWH, high-dose antioxidant, micronutrient supplementation compared to RDA supplementation had no significant effect on disease progression or ART initiation.

Clinical trial registration

ClinicalTrials.gov Identifier: NCT00798772.

The SELENOT mimetic PSELT promotes nerve regeneration by increasing axonal myelination in a facial nerve injury model in female rats

Peripheral nerve injury (PNI) is frequent and many patients suffer lifelong disabilities in severe cases. Although the peripheral nervous system is able to regenerate, its potential is limited. In this study, we tested in a nerve regeneration model in rat the potential beneficial effect of a short mimetic peptide, named PSELT, which derives from SELENOT, an essential thioredoxin-like selenoprotein endowed with neuroprotective and antioxidant activities. For this purpose, the right facial nerve of female Long-Evans rats was axotomized then bridged with a free femoral vein interposition graft. PSELT (1 μM) was injected into the vein immediately and 48 h after the injury, and the effects observed were compared to those found after an end-to-end suture used as a gold standard treatment. Whisking behavior, electrophysiological potential, and histological analyses were performed 3 months after injury to determine the effects of these treatments. These analyses revealed that PSELT-treated animals exhibit a better motor recovery in terms of protraction amplitude and velocity of vibrissae compared to control and end-sutured nerve animal groups. Moreover, administration of PSELT following injury enhanced muscle innervation, axonal elongation, and myelination of newly formed nerve fibers. Altogether, these results indicate that a PSELT-based treatment is sufficient to enhance facial nerve myelination and regeneration and could represent a new therapeutic tool to treat PNI.

A Comprehensive Overview of the Complex Role of Oxidative Stress in Aging, The Contributing Environmental Stressors and Emerging Antioxidant Therapeutic Interventions

Introduction

Aging is a normal, inevitable, irreversible, and progressive process which is driven by internal and external factors. Oxidative stress, that is the imbalance between prooxidant and antioxidant molecules favoring the first, plays a key role in the pathophysiology of aging and comprises one of the molecular mechanisms underlying age-related diseases. However, the oxidative stress theory of aging has not been successfully proven in all animal models studying lifespan, meaning that altering oxidative stress/antioxidant defense systems did not always lead to a prolonged lifespan, as expected. On the other hand, animal models of age-related pathological phenotypes showed a well-correlated relationship with the levels of prooxidant molecules. Therefore, it seems that oxidative stress plays a more complicated role than the one once believed and this role might be affected by the environment of each organism. Environmental factors such as UV radiation, air pollution, and an unbalanced diet, have also been implicated in the pathophysiology of aging and seem to initiate this process more rapidly and even at younger ages.

Aim

The purpose of this review is to elucidate the role of oxidative stress in the physiology of aging and the effect of certain environmental factors in initiating and sustaining this process. Understanding the pathophysiology of aging will contribute to the development of strategies to postpone this phenomenon. In addition, recent studies investigating ways to alter the antioxidant defense mechanisms in order to prevent aging will be presented.

Conclusions

Careful exposure to harmful environmental factors and the use of antioxidant supplements could potentially affect the biological processes driving aging and slow down the development of age-related diseases. Maybe a prolonged lifespan could not be achieved by this strategy alone, but a longer healthspan could also be a favorable target.

p66Shc in Cardiovascular Pathology

p66Shc is a widely expressed protein that governs a variety of cardiovascular pathologies by generating, and exacerbating, pro-apoptotic ROS signals. Here, we review p66Shc’s connections to reactive oxygen species, expression, localization, and discuss p66Shc signaling and mitochondrial functions. Emphasis is placed on recent p66Shc mitochondrial function discoveries including structure/function relationships, ROS identity and regulation, mechanistic insights, and how p66Shc-cyt c interactions can influence p66Shc mitochondrial function. Based on recent findings, a new p66Shc mitochondrial function model is also put forth wherein p66Shc acts as a rheostat that can promote or antagonize apoptosis. A discussion of how the revised p66Shc model fits previous findings in p66Shc-mediated cardiovascular pathology follows.

Biology of aging: Oxidative stress and RNA oxidation

The prevalence of aged people has increased rapidly in recent years and brings profound demographic changes worldwide. The multi-level progression of aging occurs at diverse stages of complexity, from cell to organ systems and eventually to the human as a whole. The cellular and molecular damages are usually regulated by the cells; repair or degrade mechanisms. However, these mechanisms are not entirely functional; their effectiveness decreases with age due to influence from endogenous sources like oxidative stress, which all contribute to the aging process. The hunt for novel strategies to increase the man's longevity since ancient times needs better understandings of the biology of aging, oxidative stress, and their roles in RNA oxidation. The critical goal in developing new strategies to increase the man's longevity is to compile the novel developed knowledge on human aging into a single picture, preferably able to understand the biology of aging and the contributing factors. This review discusses the biology of aging, oxidative stress, and their roles in RNA oxidation, leading to aging in humans.

A better index for analysis of co-occurrence and similarity

Scientists often need to know whether pairs of entities tend to occur together or independently. Standard approaches to this issue use co-occurrence indices such as Jaccard, Sørensen-Dice, and Simpson. We show that these indices are sensitive to the prevalences of the entities they describe and that this invalidates their interpretability. We propose an index, α, that is insensitive to prevalences. Published datasets reanalyzed with both α and Jaccard's index (J) yield profoundly different biological inferences. For example, a published analysis using J contradicted predictions of the island biogeography theory finding that community stability increased with increasing physical isolation. Reanalysis of the same dataset with the estimator [Formula: see text] reversed that result and supported theoretical predictions. We found similarly marked effects in reanalyses of antibiotic cross-resistance and human disease biomarkers. Our index α is not merely an improvement; its use changes data interpretation in fundamental ways.

Podophyllum hexandrum and its active constituents: Novel radioprotectants

Human exposure to radiation has expanded considerably in recent years, due to a wide range of medical, agricultural, and industrial applications. Despite its beneficial utilities, radiation is also known to have a deleterious effect on cells and tissues, largely through the creation of free radicals, which cause severe damage to biological systems through processes such as DNA double/single-strand fragmentation, protein modification, and upregulation of lipid peroxidation pathways. In addition, radiation damages genetic material while inducing hereditary genotoxicity. Developing measures to counter radiation-induced damage is thus considered to be of significant importance. Considering the inherent capability of plants to survive radiative conditions, certain plants and natural compounds have been the subject of investigations to explore and harness their natural radioprotective abilities. Podophyllum hexandrum, an Indian medicinal plant with several known traditional phytotherapeutic uses, is considered in particular to be of immense therapeutic importance. Recent studies have been conducted to validate its radioprotective potential alongside discovering its protective mechanisms following γ-radiation-induced mortality and disorder in both mice and human cells. These findings show that Podophyllum and its constituents/natural compounds protect the lungs, gastrointestinal tissues, hemopoietic system, and testis by inducing DNA repair pathways, apoptosis inhibition, free radical scavenging, metal chelation, anti-oxidation and anti-inflammatory mechanisms. In this review, we have provided an updated, comprehensive summary of ionizing radiations and their impacts on biological systems, highlighting the mechanistic and radioprotective role of natural compounds from Podophyllum hexandrum.

Oxidative Stress and Autophagy as Key Targets in Melanoma Cell Fate

Melanoma originates from the malignant transformation of melanocytes and is one of the most aggressive forms of cancer. The recent approval of several drugs has increased the chance of survival although a significant subset of patients with metastatic melanoma do not show a long-lasting response to these treatments. The complex cross-talk between oxidative stress and the catabolic process autophagy seems to play a central role in all aspects of melanoma pathophysiology, from initiation to progression and metastasis, including drug resistance. However, determining the fine role of autophagy in cancer death and in response to redox disruption is still a fundamental challenge in order to advance both basic and translational aspects of this field. In order to summarize the interactions among reactive oxygen and nitrogen species, autophagy machinery and proliferation/growth/death/apoptosis/survival, we provide here a narrative review of the preclinical evidence for drugs/treatments that modulate oxidative stress and autophagy in melanoma cells. The significance and the potential for pharmacological targeting (also through multiple and combination approaches) of these two different events, which can contribute independently or simultaneously to the fate of melanoma, may help to define new processes and their interconnections underlying skin cancer biology and unravel new reliable approaches.

Fast Antioxidant Reaction of Polyphenols and Their Metabolites

The negative correlation between diets rich in fruits and vegetables and the occurrence of cardiovascular disease, stroke, cancer, atherosclerosis, cognitive impairment and other deleterious conditions is well established, with flavonoids and other polyphenols held to be partly responsible for the beneficial effects. Initially, these effects were explained by their antioxidant ability, but the low concentrations of polyphenols in tissues and relatively slow reaction with free radicals suggested that, instead, they act by regulating cell signalling pathways. Here we summarise results demonstrating that the abandonment of an antioxidant role for food polyphenols is based on incomplete knowledge of the mechanism of the polyphenol-free radical reaction. New kinetic measurements show that the reaction is up to 1000 times faster than previously reported and lowers the damaging potential of the radicals. The results also show that the antioxidant action does not require phenolic groups, but only a carbon-centred free radical and an aromatic molecule. Thus, not only food polyphenols but also many of their metabolites are effective antioxidants, significantly increasing the antioxidant protection of cells and tissues. By restoring an important antioxidant role for food polyphenols, the new findings provide experimental support for the advocacy of diets rich in plant-derived food.

Testosterone, cortisol, vitamin D and oxydative stress and their relationships in professional soccer players

BACKGROUND

The testosterone/cortisol ratio has been used in sport physiology to evaluate the balance between anabolism and catabolism; its decrease below 30% has been considered a marker of overtraining. In this framework recent studies in soccer players have investigated the relationships between testosterone, cortisol, vitamin D and reactive oxygen species, but with unconvincing results. The aim of the present study was to evaluate the behavior of such biological parameters and their relationships both in winter (the season of championship) and in summer (off-competition season), characterized by different homeostatic situations.

PATIENTS AND METHODS

Twenty-seven professional male football players (Second Italian Division), were studied. Blood levels of free testosterone, cortisol, vitamin D and reactive oxygen species were evaluated in August (pre-season training) and in February, in the midseason. A comparison between these two periods was performed and for each of them the relationships between the biological parameters were evaluated.

RESULTS

Blood levels of testosterone were higher during summer whereas those of cortisol were higher in winter. Vitamin D levels were higher in summer; in this season a positive significant relationship between vitamin D and testosterone was observed (p=0.001), but not in winter (p=0.592). Reactive oxygen species were higher in winter; in this season a significant positive relationship between these substances and cortisol was observed (0.000), but not in summer (p=0.325).

CONCLUSIONS

In professional soccer players it was found a positive relationship between vitamin D and testosterone in summer and between reactive oxygen species and cortisol in winter. However the question whether such results are genuine cause-effect relationships or mere casual or spurious statistical correlations is still unsolved. As matter of fact, such results could be dependent from other determinants which might drive the aforementioned biological parameters in the same direction. These conclusions must be considered valid only in relation to the experimental conditions (training workload, diet and sun exposure) of the present study.

Redox-related biomarkers in human cardiovascular disease - classical footprints and beyond

Global epidemiological studies show that chronic non-communicable diseases such as atherosclerosis and metabolic disorders represent the leading cause of premature mortality and morbidity. Cardiovascular disease such as ischemic heart disease is a major contributor to the global burden of disease and the socioeconomic health costs. Clinical and epidemiological data show an association of typical oxidative stress markers such as lipid peroxidation products, 3-nitrotyrosine or oxidized DNA/RNA bases with all major cardiovascular diseases. This supports the concept that the formation of reactive oxygen and nitrogen species by various sources (NADPH oxidases, xanthine oxidase and mitochondrial respiratory chain) represents a hallmark of the leading cardiovascular comorbidities such as hyperlipidemia, hypertension and diabetes. These reactive oxygen and nitrogen species can lead to oxidative damage but also adverse redox signaling at the level of kinases, calcium handling, inflammation, epigenetic control, circadian clock and proteasomal system. The in vivo footprints of these adverse processes (redox biomarkers) are discussed in the present review with focus on their clinical relevance, whereas the details of their mechanisms of formation and technical aspects of their detection are only briefly mentioned. The major categories of redox biomarkers are summarized and explained on the basis of suitable examples. Also the potential prognostic value of redox biomarkers is critically discussed to understand what kind of information they can provide but also what they cannot achieve.

Redox regulation of immunity and the role of small molecular weight thiols

It is thought that excessive production of reactive oxygen species (ROS) can be a causal component in many diseases, some of which have an inflammatory component. This led to an oversimplification whereby ROS are seen as inflammatory and antioxidants anti-inflammatory. This paper aims at reviewing some of the literature on thiols in host defense. The review will first summarize the mechanisms by which we survive infections by pathogens. Then we will consider how the redox field evolved from the concept of oxidative stress to that of redox regulation and how it intersects the field of innate immunity. A third section will analyze how an oversimplified oxidative stress theory of disease led to a hypothesis on the role of ROS and glutathione (GSH) in immunity, respectively as pro- and anti-inflammatory mediators. Finally, we will discuss some recent research and how to think out of the box of that oversimplification and link the role of thiols in redox regulation to the mechanisms by which we survive an infection outlined in the first section.

The Role of Non-Coding RNAs in the Neuroprotective Effects of Glutathione

The establishment of antioxidative defense systems might have been mandatory for most living beings with aerobic metabolisms, because oxygen consumption produces adverse byproducts known as reactive oxygen species (ROS). The brain is especially vulnerable to the effect of ROS, since the brain has large amounts of unsaturated fatty acids, which are a target of lipid oxidation, as well as comparably high-energy consumption compared to other organs that results in ROS release from mitochondria. Thus, dysregulation of the synthesis and/or metabolism of antioxidants-particularly glutathione (GSH), which is one of the most important antioxidants in the human body-caused oxidative stress states that resulted in critical diseases, including neurodegenerative diseases in the brain. GSH plays crucial roles not only as an antioxidant but also as an enzyme cofactor, cysteine storage form, the major redox buffer, and a neuromodulator in the central nervous system. The levels of GSH are precisely regulated by uptake systems for GSH precursors as well as GSH biosynthesis and metabolism. The rapid advance of RNA sequencing technologies has contributed to the discovery of numerous non-coding RNAs with a wide range of functions. Recent lines of evidence show that several types of non-coding RNAs, including microRNA, long non-coding RNA and circular RNA, are abundantly expressed in the brain, and their activation or inhibition could contribute to neuroprotection through the regulation of GSH synthesis and/or metabolism. Interestingly, these non-coding RNAs play key roles in gene regulation and growing evidence indicates that non-coding RNAs interact with each other and are co-regulated. In this review, we focus on how the non-coding RNAs modulate the level of GSH and modify the oxidative stress states in the brain.

Oxidative Stress and Hypertension

A link between oxidative stress and hypertension has been firmly established in multiple animal models of hypertension but remains elusive in humans. While initial studies focused on inactivation of nitric oxide by superoxide, our understanding of relevant reactive oxygen species (superoxide, hydrogen peroxide, and peroxynitrite) and how they modify complex signaling pathways to promote hypertension has expanded significantly. In this review, we summarize recent advances in delineating the primary and secondary sources of reactive oxygen species (nicotinamide adenine dinucleotide phosphate oxidases, uncoupled endothelial nitric oxide synthase, endoplasmic reticulum, and mitochondria), the posttranslational oxidative modifications they induce on protein targets important for redox signaling, their interplay with endogenous antioxidant systems, and the role of inflammasome activation and endoplasmic reticular stress in the development of hypertension. We highlight how oxidative stress in different organ systems contributes to hypertension, describe new animal models that have clarified the importance of specific proteins, and discuss clinical studies that shed light on how these processes and pathways are altered in human hypertension. Finally, we focus on the promise of redox proteomics and systems biology to help us fully understand the relationship between ROS and hypertension and their potential for designing and evaluating novel antihypertensive therapies.

Cell-penetrating, antioxidant SELENOT mimetic protects dopaminergic neurons and ameliorates motor dysfunction in Parkinson's disease animal models

Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor dysfunction for which there is an unmet need for better treatment options. Although oxidative stress is a common feature of neurodegenerative diseases, notably PD, there is currently no efficient therapeutic strategy able to tackle this multi-target pathophysiological process. Based on our previous observations of the potent antioxidant and neuroprotective activity of SELENOT, a vital thioredoxin-like selenoprotein, we designed the small peptide PSELT from its redox active site to evaluate its antioxidant properties in vivo, and its potential polyfunctional activity in PD models. PSELT protects neurotoxin-treated dopaminergic neurons against oxidative stress and cell death, and their fibers against neurotoxic degeneration. PSELT is cell-permeable and acts in multiple subcellular compartments of dopaminergic neurons that are vulnerable to oxidative stress. In rodent models of PD, this protective activity prevented neurodegeneration, restored phosphorylated tyrosine hydroxylase levels, and led to improved motor skills. Transcriptomic analysis revealed that gene regulation by PSELT after MPP+ treatment negatively correlates with that occurring in PD, and positively correlates with that occurring after resveratrol treatment. Mechanistically, a major impact of PSELT is via nuclear stimulation of the transcription factor EZH2, leading to neuroprotection. Overall, these findings demonstrate the potential of PSELT as a therapeutic candidate for treatment of PD, targeting oxidative stress at multiple intracellular levels.

Diabetes-Alzheimer's Disease Link: Targeting Mitochondrial Dysfunction and Redox Imbalance

Significance: It is of common sense that the world population is aging and life expectancy is increasing. However, as the population ages, there is also an exponential risk to live into the ages where the brain-related frailties and neurodegenerative diseases develop. Hand in hand with those events, the world is witnessing a major upsurge in diabetes diagnostics. Remarkably, all of this seems to be narrowly related, and clinical and research communities highlight for the upcoming threat that it will represent for the present and future generations. Recent Advances: It is of utmost importance to clarify the influence of diabetes-related metabolic features on brain health and the mechanisms underlying the increased likelihood of developing neurodegenerative diseases, in particular Alzheimer's disease. Thereupon, a wealth of evidence suggests that mitochondria and associated oxidative stress are at the root of the link between diabetes and co-occurring disorders in the brain. Critical Issues: The scientific community has been challenged with constant failures of clinical trials raising major issues in the advance of the therapeutic field to fight chronic diseases epidemics. Thus, a change of paradigms is urgently needed. Future Directions: It has become urgent to identify new and solid candidates able to clinically reproduce the positive outcomes obtained in preclinical studies. On this basis, strategies settled to counteract diabetes-induced neurodegeneration encompassing mitochondrial dysfunction, redox status imbalance, and/or insulin dysregulation seem worth to follow. Hopefully, ongoing innovative research based on reliable experimental tools will soon bring the desired answers allowing pharmaceutical industry to apply such knowledge to human medicine.

Clinical Significance of ROMs, OXY, SHp and HMGB-1 in Canine Leishmaniosis

This study aimed to investigate the role of oxidative stress parameters (ROMs, OXY, SHp), the Oxidative Stress index (OSi), and High Mobility Group Box-1 protein (HMGB-1) in canine leishmaniosis (CanL). For this study, thirty dogs, naturally infected with Leishmania spp. (Leishmania Group, LEISH) and ten healthy adult dogs (control group, CTR) were included. The diagnosis of CanL was performed by a cytological examination of lymph nodes, real time polymerase chain reaction on biological tissues (lymph nodes and whole blood), and an immunofluorescence antibody test (IFAT) for the detection of anti-Leishmania antibodies associated with clinical signs such as dermatitis, lymphadenopathy, onychogryphosis, weight loss, cachexia, lameness, conjunctivitis, epistaxis, and hepatosplenomegaly. The HMGB-1 and oxidative stress parameters of the LEISH Group were compared with the values recorded in the CTR group (Mann Whitney Test, p < 0.05). Spearman rank correlation was applied to evaluate the correlation between the HMGB-1, oxidative stress biomarkers, hematological and biochemical parameters in the LEISH Group. Results showed statistically significant higher values of SHp in the LEISH Group. Specific correlation between the ROMs and the number of red blood cells, and between HGMB-1 and SHp were recorded. These preliminary data may suggest the potential role of oxidative stress in the pathogenesis of CanL. Further studies are undoubtedly required to evaluate the direct correlation between inflammation parameters with the different stages of CanL. Similarly, further research should investigate the role of ROMs in the onset of anemia.

Nobiletin Exhibits Neuroprotective Effects against Mitochondrial Complex I Inhibition via Regulating Apoptotic Signaling

Nobiletin, a polymethoxylated flavonoid found in citrus, has been studied because of its modulatory functions in cellular signaling cascades, and effects to prevent mitochondrial calcium overload and neuronal cell death. Particularly, we previously reported that nobiletin induced changes in the mitochondrial membrane potential through K⁺ channel regulation, suggesting that nobiletin might exert neuroprotective effects via regulating mitochondrial functions associated with the electron transport chain (ETC) system. This study investigated whether nobiletin regulated mitochondrial dysfunction mediated by ETC system downregulation by inhibiting complex I (CI) and complex III (CIII) in pure mitochondria and the cortical neurons of rats. The results showed that nobiletin significantly reduced mitochondrial reactive oxygen species (ROS) production, inhibited apoptotic signaling, enhanced ATP production and then restored neuronal viability under conditions of CI inhibition, but not CIII inhibition. These effects were attributed to the downregulation of translocation of apoptosis-induced factor (AIF), and the upregulation of CI activity and the expression of antioxidant enzymes such as Nrf2 and HO-1. Together with our previous study, these results indicate that the neuroprotective effects of nobiletin under mitochondrial dysfunction may be associated with its function to activate antioxidant signaling cascades. Our findings suggest the possibility that nobiletin has therapeutic potential in treating oxidative neurological and neurodegenerative diseases mediated by mitochondrial dysfunction.

Inhibition of miR-96-5p in the mouse brain increases glutathione levels by altering NOVA1 expression

Glutathione (GSH) is an important antioxidant that plays a critical role in neuroprotection. GSH depletion in neurons induces oxidative stress and thereby promotes neuronal damage, which in turn is regarded as a hallmark of the early stage of neurodegenerative diseases. The neuronal GSH level is mainly regulated by cysteine transporter EAAC1 and its inhibitor, GTRAP3-18. In this study, we found that the GTRAP3-18 level was increased by up-regulation of the microRNA miR-96-5p, which was found to decrease EAAC1 levels in our previous study. Since the 3'-UTR region of GTRAP3-18 lacks the consensus sequence for miR-96-5p, an unidentified protein should be responsible for the intermediate regulation of GTRAP3-18 expression by miR-96-5p. Here, we discovered that RNA-binding protein NOVA1 functions as an intermediate protein for GTRAP3-18 expression via miR-96-5p. Moreover, we show that intra-arterial injection of a miR-96-5p-inhibiting nucleic acid to living mice by a drug delivery system using microbubbles and ultrasound decreased the level of GTRAP3-18 via NOVA1 and increased the levels of EAAC1 and GSH in the dentate gyrus of the hippocampus. These findings suggest that the delivery of a miR-96-5p inhibitor to the brain would efficiently increase the neuroprotective activity by increasing GSH levels via EAAC1, GTRAP3-18 and NOVA1.

Evaluation of Oxidative Stress before and after Using Laser and Photoactivation Therapy as Adjuvant of Non-Surgical Periodontal Treatment in Patients with Rheumatoid Arthritis

(1) Background: The aim of this split-mouth design study was to analyze the clinical periodontal indexes and oxidative stress markers in gingival crevicular fluid modifications after three periodontal disease treatment possibilities (scaling and root planning-SRP; SRP and diode laser-L; SRP and photodynamic therapy-PDT). (2) Methods: The study was conducted on 52 patients: systemically healthy subjects with periodontal disease-non-RA (n = 26); and test group (n = 26) subjects with rheumatoid arthritis and periodontal disease-RA. Clinical periodontal measurements (probing depth-PD; Löe and Silness gingival index-GI; papillary bleeding index-PBI; and periodontal community index of treatment needs-CPITN) and oxidative stress markers (8-hydroxy-2'-deoxyguanosine (8-OHdG) and 4 hydroxynonenal (4-HNE)) were analyzed at baseline (T0), after three sessions of periodontal treatment (T1), and 6 months after treatment (T2). (3) Results: Periodontal therapy improved clinical periodontal measurements and oxidative stress markers in both analyzed groups, with supplementary benefits for laser- and PDT-treated periodontal pockets. (4) Conclusions: The analyzed oxidative stress markers decreased significantly following non-surgical periodontal therapy in both rheumatoid arthritis and systemically healthy patients. All the periodontal disease treatment possibilities analyzed in this study offered clinical and paraclinical improvements; however, the association of laser with SRP and photodisinfection with SRP yielded the best clinical and paraclinical outcomes when compared to SRP alone.

Demystifying Oxidative Stress

The hypothesis that reactive oxygen species (ROS) can be not just associated with but causally implicated in disease was first made in 1956, but so far, the oxidative stress theory of disease has not led to major therapeutic breakthrough, and the use of antioxidant is now confined to the field of complementary medicine. This chapter reviews the lack of high-level clinical evidence for the effectiveness of antioxidants in preventing disease and the epistemological problems of the oxidative stress theory of disease. We conclude on possible ways forward to test this hypothesis with approaches that take into account personalized medicine. The previous oxidative stress model has helped neither to diagnose nor to treat possibly ROS-related or ROS-dependent diseases. The redox balance concept that low ROS levels are beneficial or tolerable and high levels are disease triggers and best reduced is apparently wrong. Physiological ROS signalling may become dysfunctional or a disease trigger by at least five mechanisms: a physiological source may appear at an unphysiological site, a physiological source may be underactivated (less common) or overactivated (more common), a new source may appear, a physiological source may be overactivated or underactivated, and a toxifying enzyme may convert an ROS signal molecule into a more reactive molecule. The latter three mechanisms may reach a physiological or nonphysiological target. All of these dysregulations may be the direct and essential cause of a disease (rarely the case) or just a secondary epiphenomenon, which will disappear once the non-ROS-related cause of the disease is cured (much more common). Importantly, these mechanisms are the same for almost every signalling system. Causal target validation (sources, toxifiers and targets) is essential in order to identify effective drugs and therapies for ROSopathies.

Mini-Review on Lipofuscin and Aging: Focusing on The Molecular Interface, The Biological Recycling Mechanism, Oxidative Stress, and The Gut-Brain Axis Functionality

Intra-lysosomal accumulation of the autofluorescent "residue" known as lipofuscin, which is found within postmitotic cells, remains controversial. Although it was considered a harmless hallmark of aging, its presence is detrimental as it continually accumulates. The latest evidence highlighted that lipofuscin strongly correlates with the excessive production of reactive oxygen species; however, despite this, lipofuscin cannot be removed by the biological recycling mechanisms. The antagonistic effects exerted at the DNA level culminate in a dysregulation of the cell cycle, by inducing a loss of the entire internal environment and abnormal gene(s) expression. Additionally, it appears that a crucial role in the production of reactive oxygen species can be attributed to gut microbiota, due to their ability to shape our behavior and neurodevelopment through their maintenance of the central nervous system.

Nuclear factor erythroid 2-related factor 2 (Nrf2) as a potential therapeutic target for vitiligo

Vitiligo is an autoimmune disease of the skin which causes loss of melanocytes from the epidermis. Recently, it is demonstrated that oxidative stress (OS) plays a significant role in the immuno-pathogenesis of vitiligo. A major mechanism in the cellular defense against OS is activation of the nuclear factor erythroid2-related factor (Nrf2)-Kelch-like ECH-associated protein 1(Keap1)-antioxidant responsive element (ARE) signaling pathway. Recently it has been shown that vitiligo melanocytes have impaired Nrf2-ARE signaling. A number of drugs including those known as Nrf2 activators and those known to possess effects to activate Nrf2, have been used in treating vitiligo with certain therapeutic effects. Also, studies have shown that a number of compounds can protect melanocytes against OS via activating Nrf2. These compounds may be considered as candidates for developing new drugs for vitiligo in the future. Nrf2 can be considered as a potential therapeutic target for vitiligo.

Engineered nanoparticle-induced epigenetic changes: An important consideration in nanomedicine

Engineered nanoparticles (ENPs) are now being applied across a range of disciplines, and as a result numerous studies have now assessed ENP-related bioeffects. Among them, ENP-induced epigenetic changes including DNA methylation, histone modifications, and miRNA-mediated regulation of gene expression have recently attracted attention. In this review, we describe the diversity of ENP-induced epigenetic changes, focusing on their interplay with related functional biological events, especially oxidative stress, MAPK pathway activation, and inflammation. In doing so, we highlight the underlying mechanisms and biological effects of ENP-induced epigenetic changes. We also summarize how high-throughput technologies have helped to uncover ENP-induced epigenetic changes. Finally, we discuss future perspectives and the challenges related to ENP-induced epigenetic changes that still need to be addressed.