Aging-Related Decline of Glutathione Peroxidase 3 and Risk of Cardiovascular Events in Patients With Atrial Fibrillation

Thrombosis and Aging: Fibrin Clot Properties and Oxidative Stress

Significance: Aging is a complex process associated with an increased risk of many diseases, including thrombosis. This review summarizes age-related prothrombotic mechanisms in clinical settings of thromboembolism, focusing on the role of fibrin structure and function modified by oxidative stress. Recent Advances: Aging affects blood coagulation and fibrinolysis via multiple mechanisms, including enhanced oxidative stress, with an imbalance in the oxidant/antioxidant mechanisms, leading to loss of function and accumulation of oxidized proteins, including fibrinogen. Age-related prothrombotic alterations are multifactorial involving enhanced platelet activation, endothelial dysfunction, and changes in coagulation factors and inhibitors. Formation of more compact fibrin clot networks displaying impaired susceptibility to fibrinolysis represents a novel mechanism, which might contribute to atherothrombosis and venous thrombosis. Alterations to fibrin clot structure/function are at least in part modulated by post-translational modifications of fibrinogen and other proteins involved in thrombus formation, with a major impact of carbonylation. Fibrin clot properties are also involved in the efficacy and safety of therapy with oral anticoagulants, statins, and/or aspirin. Critical Issues: Since a prothrombotic state is observed in very elderly individuals free of diseases associated with thromboembolism, the actual role of activated blood coagulation in health remains elusive. It is unclear to what extent oxidative modifications of coagulation and fibrinolytic proteins, in particular fibrinogen, contribute to a prothrombotic state in healthy aging. Future Directions: Ongoing studies will show whether novel therapies that may alter oxidative stress and fibrin characteristics are beneficial to prevent atherosclerosis and thromboembolic events associated with aging.

Insights into the Role of Glutathione Peroxidase 3 in Non-Neoplastic Diseases

Reactive oxygen species (ROSs) are byproducts of normal cellular metabolism and play pivotal roles in various physiological processes. Disruptions in the balance between ROS levels and the body's antioxidant defenses can lead to the development of numerous diseases. Glutathione peroxidase 3 (GPX3), a key component of the body's antioxidant system, is an oxidoreductase enzyme. GPX3 mitigates oxidative damage by catalyzing the conversion of hydrogen peroxide into water. Beyond its antioxidant function, GPX3 is vital in regulating metabolism, modulating cell growth, inducing apoptosis and facilitating signal transduction. It also serves as a significant tumor suppressor in various cancers. Recent studies have revealed aberrant expression of GPX3 in several non-neoplastic diseases, associating it with multiple pathological processes. This review synthesizes the current understanding of GPX3 expression and regulation, highlighting its extensive roles in noncancerous diseases. Additionally, this paper evaluates the potential of GPX3 as a diagnostic biomarker and explores emerging therapeutic strategies targeting this enzyme, offering potential avenues for future clinical treatment of non-neoplastic conditions.

Single-Cell RNA Sequencing Reveals Cardiac Fibroblast-Specific Transcriptomic Changes in Dilated Cardiomyopathy

Dilated cardiomyopathy (DCM) is the most common cause of heart failure, with a complex aetiology involving multiple cell types. We aimed to detect cell-specific transcriptomic alterations in DCM through analysis that leveraged recent advancements in single-cell analytical tools. Single-cell RNA sequencing (scRNA-seq) data from human DCM cardiac tissue were subjected to an updated bioinformatic workflow in which unsupervised clustering was paired with reference label transfer to more comprehensively annotate the dataset. Differential gene expression was detected primarily in the cardiac fibroblast population. Bulk RNA sequencing was performed on an independent cohort of human cardiac tissue and compared with scRNA-seq gene alterations to generate a stratified list of higher-confidence, fibroblast-specific expression candidates for further validation. Concordant gene dysregulation was confirmed in TGFβ-induced fibroblasts. Functional assessment of gene candidates showed that AEBP1 may play a significant role in fibroblast activation. This unbiased approach enabled improved resolution of cardiac cell-type-specific transcriptomic alterations in DCM.

Selenium status and its determinants in very old adults: insights from the Newcastle 85+ Study

There is a dearth of data on Se status in very old adults. The aims of this study were to assess Se status and its determinants in 85-year-olds living in the Northeast of England by measuring serum Se and selenoprotein P (SELENOP) concentrations and glutathione peroxidase 3 (GPx3) activity. A secondary aim was to examine the interrelationships between each of the biomarkers. In total, 757 participants (463 women, 293 men) from the Newcastle 85+ Study were included. Biomarker concentrations were compared with selected cut-offs (serum Se: suboptimal 70 µg/l and deficient 45 µg/l; SELENOP: suboptimal 4·5 mg/l and deficient 2·6 mg/l). Determinants were assessed using linear regressions, and interrelationships were assessed using restricted cubic splines. Median (inter-quartile range) concentrations of serum Se, SELENOP and of GPx3 activity were 53·6 (23·6) µg/l, 2·9 (1·9) mg/l and 142·1 (50·7) U/l, respectively. Eighty-two percentage and 83 % of participants had suboptimal serum Se (< 70 µg/l) and SELENOP (< 4·5 mg/l), and 31 % and 40 % of participants had deficient serum Se (< 45 µg/l) and SELENOP (< 2·6 mg/l), respectively. Protein intake was a significant determinant of Se status. Additional determinants of serum Se were sex, waist:hip ratio, self-rated health and disease, while sex, BMI and physical activity were determinants of GPx3 activity. There was a linear association between serum Se and SELENOP, and nonlinear associations between serum Se and GPx3 activity and between SELENOP and GPx3 activity. These findings indicate that most participants had suboptimal Se status to saturate circulating SELENOP.

Glutathione and glutathione-dependent enzymes: From biochemistry to gerontology and successful aging

The tripeptide glutathione (GSH), namely γ-L-glutamyl-L-cysteinyl-glycine, is an ubiquitous low-molecular weight thiol nucleophile and reductant of utmost importance, representing the central redox agent of most aerobic organisms. GSH has vital functions involving also antioxidant protection, detoxification, redox homeostasis, cell signaling, iron metabolism/homeostasis, DNA synthesis, gene expression, cysteine/protein metabolism, and cell proliferation/differentiation or death including apoptosis and ferroptosis. Various functions of GSH are exerted in concert with GSH-dependent enzymes. Indeed, although GSH has direct scavenging antioxidant effects, its antioxidant function is substantially accomplished by glutathione peroxidase-catalyzed reactions with reductive removal of H2O2, organic peroxides such as lipid hydroperoxides, and peroxynitrite; to this antioxidant activity also contribute peroxiredoxins, enzymes further involved in redox signaling and chaperone activity. Moreover, the detoxifying function of GSH is basically exerted in conjunction with glutathione transferases, which have also antioxidant properties. GSH is synthesized in the cytosol by the ATP-dependent enzymes glutamate cysteine ligase (GCL), which catalyzes ligation of cysteine and glutamate forming γ-glutamylcysteine (γ-GC), and glutathione synthase, which adds glycine to γ-GC resulting in GSH formation; GCL is rate-limiting for GSH synthesis, as is the precursor amino acid cysteine, which may be supplemented as N-acetylcysteine (NAC), a therapeutically available compound. After its cell export, GSH is degraded extracellularly by the membrane-anchored ectoenzyme γ-glutamyl transferase, a process occurring, as GSH synthesis and export, in the γ-glutamyl cycle. GSH degradation occurs also intracellularly by the cytoplasmic enzymatic ChaC family of γ-glutamyl cyclotransferase. Synthesis and degradation of GSH, together with its export, translocation to cell organelles, utilization for multiple essential functions, and regeneration from glutathione disulfide by glutathione reductase, are relevant to GSH homeostasis and metabolism. Notably, GSH levels decline during aging, an alteration generally related to impaired GSH biosynthesis and leading to cell dysfunction. However, there is evidence of enhanced GSH levels in elderly subjects with excellent physical and mental health status, suggesting that heightened GSH may be a marker and even a causative factor of increased healthspan and lifespan. Such aspects, and much more including GSH-boosting substances administrable to humans, are considered in this state-of-the-art review, which deals with GSH and GSH-dependent enzymes from biochemistry to gerontology, focusing attention also on lifespan/healthspan extension and successful aging; the significance of GSH levels in aging is considered also in relation to therapeutic possibilities and supplementation strategies, based on the use of various compounds including NAC-glycine, aimed at increasing GSH and related defenses to improve health status and counteract aging processes in humans.

Glutathione Peroxidase 3 induced mitochondria-mediated apoptosis via AMPK /ERK1/2 pathway and resisted autophagy-related ferroptosis via AMPK/mTOR pathway in hyperplastic prostate

BACKGROUND

Benign prostatic hyperplasia (BPH) is a common disease in elderly men, mainly resulted from an imbalance between cell proliferation and death. Glutathione peroxidase 3 (GPX3) was one of the differentially expressed genes in BPH identified by transcriptome sequencing of 5 hyperplastic and 3 normal prostate specimens, which had not been elucidated in the prostate. This study aimed to ascertain the mechanism of GPX3 involved in cell proliferation, apoptosis, autophagy and ferroptosis in BPH.

METHODS

Human prostate tissues, GPX3 silencing and overexpression prostate cell (BPH-1 and WPMY-1) models and testosterone-induced rat BPH (T-BPH) model were utilized. The qRT-PCR, CCK8 assay, flow cytometry, Western blotting, immunofluorescence, hematoxylin and eosin, masson's trichrome, immunohistochemical staining and transmission electron microscopy analysis were performed during in vivo and in vitro experiments.

RESULTS

Our study indicated that GPX3 was localized both in the stroma and epithelium of prostate, and down-regulated in BPH samples. Overexpression of GPX3 inhibited AMPK and activated ERK1/2 pathway, thereby inducing mitochondria-dependent apoptosis and G0/G1 phase arrest, which could be significantly reversed by MEK1/2 inhibitor U0126 preconditioning. Moreover, overexpression of GPX3 further exerted anti-autophagy by inhibiting AMPK/m-TOR and up-regulated nuclear factor erythroid 2-related factor 2 (Nrf2)/glutathione peroxidase 4 (GPX4, mitochondrial GPX4 and cytoplasmic GPX4) to antagonize autophagy-related ferroptosis. Consistently, GPX3 deficiency generated opposite changes in both cell lines. Finally, T-BPH rat model was treated with GPX3 indirect agonist troglitazone (TRO) or GPX4 inhibitor RAS-selective lethal 3 (RSL3) or TRO plus RSL3. These treatments produced significant atrophy of the prostate and related molecular changes were similar to our in vitro observations.

CONCLUSIONS

Our novel data manifested that GPX3, which was capable of inducing apoptosis via AMPK/ERK1/2 pathway and antagonizing autophagy-related ferroptosis through AMPK/m-TOR signalling, was a promising therapeutic target for BPH in the future.

Measures of Oxidative Status Markers in Relation to Age, Sex, and Season in Sick and Healthy Captive Asian Elephants in Thailand

Oxidative stress is a pathological condition that can have adverse effects on animal health, although little research has been conducted on wildlife species. In this study, blood was collected from captive Asian elephants for the assessment of five serum oxidative status markers (reactive oxygen species (ROS) concentrations; malondialdehyde, MDA; albumin; glutathione peroxidase, GPx; and catalase) in healthy (n = 137) and sick (n = 20) animals. Health problems consisted of weakness, puncture wounds, gastrointestinal distress, eye and musculoskeletal problems, and elephant endotheliotropic herpesvirus hemorrhagic disease (EEHV-HD). Fecal samples were also collected to assess glucocorticoid metabolites (fGCMs) as a measure of stress. All data were analyzed in relation to age, sex, sampling season, and their interactions using generalized linear models, and a correlation matrix was constructed. ROS and serum albumin concentrations exhibited the highest concentrations in aged elephants (>45 years). No sex differences were found for any biomarker. Interactions were observed for age groups and seasons for ROS and catalase, while GPx displayed a significant interaction between sex and season. In pairwise comparisons, significant increases in ROS and catalase were observed in summer, with higher ROS concentrations observed only in the adult female group. Lower catalase activity was exhibited in juvenile males, subadult males, adult females, and aged females compared to subadult and adult elephants (males and females) in winter and the rainy season. There was a positive association between catalase activity and fGCMs (r = 0.23, p < 0.05), and a number of red blood cell parameters were positively associated with several of these biomarkers, suggesting high oxidative and antioxidative activity covary in red cells (p < 0.05). According to health status, elephants with EEHV-HD showed the most significant changes in oxidative stress markers, with MDA, GPx, and catalase being higher and albumin being lower than in healthy elephants. This study provides an analysis of understudied health biomarkers in Asian elephants, which can be used as additional tools for assessing the health condition of this species and suggests age and season may be important factors in data interpretation.

Metabolic landscape in cardiac aging: insights into molecular biology and therapeutic implications

Cardiac aging is evident by a reduction in function which subsequently contributes to heart failure. The metabolic microenvironment has been identified as a hallmark of malignancy, but recent studies have shed light on its role in cardiovascular diseases (CVDs). Various metabolic pathways in cardiomyocytes and noncardiomyocytes determine cellular senescence in the aging heart. Metabolic alteration is a common process throughout cardiac degeneration. Importantly, the involvement of cellular senescence in cardiac injuries, including heart failure and myocardial ischemia and infarction, has been reported. However, metabolic complexity among human aging hearts hinders the development of strategies that targets metabolic susceptibility. Advances over the past decade have linked cellular senescence and function with their metabolic reprogramming pathway in cardiac aging, including autophagy, oxidative stress, epigenetic modifications, chronic inflammation, and myocyte systolic phenotype regulation. In addition, metabolic status is involved in crucial aspects of myocardial biology, from fibrosis to hypertrophy and chronic inflammation. However, further elucidation of the metabolism involvement in cardiac degeneration is still needed. Thus, deciphering the mechanisms underlying how metabolic reprogramming impacts cardiac aging is thought to contribute to the novel interventions to protect or even restore cardiac function in aging hearts. Here, we summarize emerging concepts about metabolic landscapes of cardiac aging, with specific focuses on why metabolic profile alters during cardiac degeneration and how we could utilize the current knowledge to improve the management of cardiac aging.

Integrated transcriptomic and proteomic analysis reveals potential targets for heart regeneration

Research on the regenerative capacity of the neonatal heart could open new avenues for the treatment of myocardial infarction (MI). However, the mechanism of cardiac regeneration remains unclear. In the present study, we constructed a mouse model of heart regeneration and then performed transcriptomic and proteomic analyses on them. Gene Ontology (GO) enrichment analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, and Gene Set Enrichment Analysis (GSEA) of differentially expressed genes (DEGs) were conducted. Western blot (WB) and qPCR analyses were used to validate the hub genes expression. As a result, gene expression at the mRNA level and protein level is not the same. We identified 3186 DEGs and 42 differentially expressed proteins (DEPs). Through functional analysis of DEGs and DEPs, we speculate that biological processes such as ubiquitination, cell cycle, and oxygen metabolism are involved in heart regeneration. Integrated transcriptomic and proteomic analysis identified 19 hub genes and Ankrd1, Gpx3, and Trim72 were screened out as potential regulators of cardiac regeneration through further expression verification. In conclusion, we combined transcriptomic and proteomic analyses to characterize the molecular features during heart regeneration in neonatal mice. Finally, Ankrd1, Gpx3, and Trim72 were identified as potential targets for heart regeneration therapy.

Increased expression of glutathione peroxidase 3 prevents tendinopathy by suppressing oxidative stress

Tendinopathy, a degenerative disease, is characterized by pain, loss of tendon strength, or rupture. Previous studies have identified multiple risk factors for tendinopathy, including aging and fluoroquinolone use; however, its therapeutic target remains unclear. We analyzed self-reported adverse events and the US commercial claims data and found that the short-term use of dexamethasone prevented both fluoroquinolone-induced and age-related tendinopathy. Rat tendons treated systemically with fluoroquinolone exhibited mechanical fragility, histological change, and DNA damage; co-treatment with dexamethasone attenuated these effects and increased the expression of the antioxidant enzyme glutathione peroxidase 3 (GPX3), as revealed via RNA-sequencing. The primary role of GPX3 was validated in primary cultured rat tenocytes treated with fluoroquinolone or H₂O₂, which accelerates senescence, in combination with dexamethasone or viral overexpression of GPX3. These results suggest that dexamethasone prevents tendinopathy by suppressing oxidative stress through the upregulation of GPX3. This steroid-free approach for upregulation or activation of GPX3 can serve as a novel therapeutic strategy for tendinopathy.

Transcriptomic Profiling Unravels Novel Deregulated Gene Signatures Associated with Acute Myocardial Infarction: A Bioinformatics Approach

Acute myocardial infarction (AMI) is a severe disease with elevated morbidity and mortality rate worldwide. This is attributed to great losses of cardiomyocytes, which can trigger the alteration of gene expression patterns. Although several attempts have been made to assess the AMI biomarkers, to date their role in rescuing myocardial injury remains unclear. Therefore, the current study investigated three independent microarray-based gene expression datasets from AMI patients (n = 85) and their age-sex-matched healthy controls (n = 70), to identify novel gene signatures that might be involved in cardioprotection. The differentially expressed genes (DEGs) were analyzed using 'GEO2R', and weighted gene correlation network analysis (WGCNA) was performed to identify biomarkers/modules. We found 91 DEGs, of which the number of upregulated and downregulated genes were 22 and 5, respectively. Specifically, we found that the deregulated genes such as ADOR-A3, BMP6, VPS8, and GPx3, may be associated with AMI. WGCNA revealed four highly preserved modules among all datasets. The 'Enrichr' unveiled the presence of miR-660 and STAT1, which is known to affect AMI severity. Conclusively, these genes and miRNA might play a crucial role the rescue of cardiomyocytes from severe damage, which could be helpful in developing appropriate therapeutic strategies for the management of AMI.

Decrease of glutathione peroxidase in arrhythmic cardiac pathology in young individuals and its therapeutic implications

Glutathione peroxidase (GPx), as an antioxidant enzyme, is involved in the regulation of processes that cause cellular oxidative stress, with implications in various pathologies. The aim of the present study was to evaluate GPx variations in patients with arrhythmic, non-structural cardiac disorders. The research was performed on 120 patients, with a mean age of 33 years old, divided into 3 equal groups, of which 2 groups included patients with cardiac arrhythmias, the first group, associated with dyslipidemia and the second one, without dyslipidemia, and a control group consisting of healthy individuals. The method for determining GPx was based on the GPx enzyme catalysis reaction of the reduced glutathione (GSH) oxidation reaction by cumene hydroperoxide. The results revealed that GPx variation was decreased in patients with cardiac arrhythmias, with or without dyslipidemia, up to 66 and 74% of mean control values, respectively, the differences being statistically significant, showing the existence of an oxidative stress imbalance, that may be involved in triggering arrhythmogenic electrochemical mechanisms. The GPx deficiency determined in relation to cardiac arrhythmias was in dyslipidemic and non-lipidemic patients as follows: 29-35% in sinus bradycardia, 31-35% in associated cardiac arrhythmias, 30-33% in sinus tachycardia, 27-33% in atrial fibrillation, 32-33% in atrial flutter, 27-32% in atrial extrasystolic arrhythmia, 28-30% in ventricular extrasystolic arrhythmia and 18-26% in paroxysmal supraventricular tachycardia. Collectively, the results revealed that GPx, an antioxidant enzyme, is a specific biomarker, whose decrease indicated the existence of oxidative stress in young individuals with cardiac arrhythmias and its involvement in arrhythmogenic electrochemical processes. In addition, GPx deficiencies were between 18-35% in all types of cardiac arrhythmias, the highest being recorded in sinus bradycardia and the lowest in paroxysmal supraventircular tachycardia. Furthermore, the oxidative stress favored by the decrease of GPx induced lipid oxidation, regardless of the presence or absence of dyslipidemia, which triggered the formation of anti-lipid antibodies and a subclinical endothelial aggression, with early atherosclerotic potential. GPx evaluation may argue for the existence of oxidative stress in non-structural cardiac arrhythmias, and by its proper correction (antioxidants), prophylaxis of atherogenic dysfunction.

Selenoproteins and the senescence-associated epitranscriptome

Selenium is a naturally found trace element, which provides multiple benefits including antioxidant, anticancer, and antiaging, as well as boosting immunity. One unique feature of selenium is its incorporation as selenocysteine, a rare 21st amino acid, into selenoproteins. Twenty-five human selenoproteins have been discovered, and a majority of these serve as crucial antioxidant enzymes for redox homeostasis. Unlike other amino acids, incorporation of selenocysteine requires a distinctive UGA stop codon recoding mechanism. Although many studies correlating selenium, selenoproteins, aging, and senescence have been performed, it has not yet been explored if the upstream events regulating selenoprotein synthesis play a role in senescence-associated pathologies. The epitranscriptomic writer alkylation repair homolog 8 (ALKBH8) is critical for selenoprotein production, and its deficiency can significantly decrease levels of selenoproteins that are essential for reactive oxygen species (ROS) detoxification, and increase oxidative stress, one of the major drivers of cellular senescence. Here, we review the potential role of epitranscriptomic marks that govern selenocysteine utilization in regulating the senescence program.

The Status of Oxidative Stress in Patients with Alcohol Dependence: A Meta-Analysis

Alcohol-induced oxidative stress (OS) plays a pivotal role in the pathophysiology of alcohol dependence (AD). This meta-analysis was aimed at investigating the changes in the levels of OS biomarkers in AD patients. We included relevant literature published before 1 April 2022, from the PubMed, Web of Science, and EBSCO databases following PRISMA guidelines. Finally, 15 eligible articles were enrolled in this meta-analysis, including 860 patients and 849 controls. Compared with healthy controls, AD patients had lower activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) enzymes, and lower levels of albumin, while levels of malondialdehyde (MDA), vitamin B12, homocysteine, and bilirubin were significantly increased in serum/plasma samples of AD subjects (all p < 0.05). In male patients, the activities of SOD and GPx were increased in serum/plasma but decreased in erythrocytes (all p < 0.05). The opposite trends in the level of SOD and GPx activities in serum/plasma and erythrocytes of male patients could be used as the biomarker of alcohol-induced OS injury, and the synergistic changes of MDA, vitamin B12, albumin, bilirubin, and homocysteine levels should also be considered.

Aging-Related Decline of Autophagy in Patients with Atrial Fibrillation-A Post Hoc Analysis of the ATHERO-AF Study

Background: Aging is an independent risk factor for cardiovascular diseases. The autophagy process may play a role in delaying aging and improving cardiovascular function in aging. Data regarding autophagy in atrial fibrillation (AF) patients are lacking. Methods: A post hoc analysis of the prospective ATHERO-AF cohort study, including 150 AF patients and 150 sex- and age-matched control subjects (CS), was performed. For the analysis, the population was divided into three age groups: <50−60, 61−70, and >70 years. Oxidative stress (Nox2 activity and hydrogen peroxide, H2O2), platelet activation (PA) by sP-selectin and CD40L, endothelial dysfunction (nitric oxide, NO), and autophagy parameters (P62 and ATG5 levels) were assessed. Results: Nox2 activity and H2O2 production were higher in the AF patients than in the CS; conversely, antioxidant capacity was decreased in the AF patients compared to the CS, as was NO production. Moreover, sP-selectin and CD40L were higher in the AF patients than in the CS. The autophagy process was also significantly impaired in the AF patients. We found a significant difference in oxidative stress, PA, NO production, and autophagy across the age groups. Autophagy markers correlated with oxidative stress, PA, and endothelial dysfunction in both groups. Conclusions: This study provides evidence that the autophagy process may represent a mechanism for increased cardiovascular risk in the AF population.

Mediterranean Diet: A Tool to Break the Relationship of Atrial Fibrillation with the Metabolic Syndrome and Non-Alcoholic Fatty Liver Disease

Atrial fibrillation (AF) is the most common supraventricular arrhythmia associated with increased cardiovascular and non-cardiovascular morbidity and mortality. As multiple factors may predispose the onset of AF, the prevention of the occurrence, recurrence and complications of this arrhythmia is still challenging. In particular, a high prevalence of cardio-metabolic comorbidities such as the metabolic syndrome (MetS) and in its hepatic manifestation, the non-alcoholic fatty liver disease (NAFLD), have been described in the AF population. A common pathogenetic mechanism linking AF, MetS and NAFLD is represented by oxidative stress. For this reason, in the past decades, numerous studies have investigated the effect of different foods/nutrients with antioxidant properties for the prevention of, and their therapeutic role is still unclear. In this narrative comprehensive review, we will summarize current evidence on (1) the association between AF, MetS and NAFLD (2) the antioxidant role of Mediterranean Diet and its components for the prevention of AF and (3) the effects of Mediterranean Diet on MetS components and NAFLD.

Comparative Studies of Orthovanadate Nanoparticles and Metformin on Life Quality and Survival of Senile Wistar Rats

Effect of prolong use of orthovanadate nanoparticles (GdVO₄/Eu³⁺ NPs (8 × 25 nm)) on life quality and survival of male Wistar rats on the late stage of ontogenesis (from 23 months to the end of life) has been investigated. Multi-parametric assessment of orthovanadate NPs influences against metformin (Met) which is a well-known calorie restriction mimetic (CR-mimetic) has been completed. The quality of life was assessed by taking into account age-related hallmarks-phenotype and some physiological parameters (condition of the coat, body weight, concentration of thyroxine, rectal temperature) as well as indicators of the pro-oxidant/antioxidant balance of blood and liver (the content of lipid hydroperoxides; aconitase, glutathione peroxidase, glutathione reductase, glutaredoxin activity, and activity of NADP⁺-dehydrogenases (DG) (glucose-6-phosphate DG, malate DG, and isocitrate DG)) in aging animals. Kaplan-Meier curve and Gehan tests with Yates' correction were performed for the survival analysis. It has been found that long-term use of GdVO₄/Eu³⁺ NPs (0.25-0.30 mg/kg/day), as well as Met (100-110 mg/kg/day) with drinking water led to reliable improvement of physiological parameters and normalization of the pro-oxidant/antioxidant balance in the liver and blood of experimental animals. A significant increase in the survival rate of aging rats was observed; the apparent median survival for control rats was 900 days, while for experimental rats, 1010 and 990 days for GdVO₄/Eu³⁺ NPs and Met, respectively. In general, the data obtained demonstrate the ability of GdVO₄/Eu³⁺ NPs and CR-mimetic-Met to improve the quality of life and increase the survival of an elderly organism.

Interventional study with vitamin E in cardiovascular disease and meta-analysis

Cardiovascular disease (CVD) is one of the major causes of morbidity and mortality and atherosclerosis is the common root to most of the CVD. Oxidative stress is one of the most important factors driving atherosclerosis and its complications. Thus, strategies for the prevention and treatment of cardiovascular events had oxidative changes as a potential target. Natural vitamin E consists of a family of eight different compounds, four tocopherols and four tocotrienols. All tocopherols and tocotrienols are potent antioxidants with lipoperoxyl radical-scavenging activities. In addition, α-tocopherol possesses also anti-inflammatory as well as anti-atherothrombotic effects by modulating platelet and clotting system. Experimental and in vitro studies described molecular and cellular signalling pathways regulated by vitamin E antithrombotic and antioxidant properties. While observational studies demonstrated an inverse association between vitamin E serum levels and CVD, interventional trials with vitamin supplements provided negative results. This review focus on the impact of vitamin E in the atherothrombotic process and describes the results of experimental and clinical studies with the caveats related to the interventional trials with vitamin E to prevent CVD.

Therapeutic enzymes as non-conventional targets in cardiovascular impairments:A Comprehensive Review

Over the last few decades, substantial progress has been made towards the understanding of cardiovascular diseases (CVDs). In-depth mechanistic insights have also provided opportunities to explore novel therapeutic targets and treatment regimens to be discovered. Therapeutic enzymes are an example of such opportunities. The balanced functioning of such enzymes protects against a variety of CVDs while on the other hand, even a small shift in the normal functioning of these enzymes may lead to deleterious outcomes. Owing to the great versatility of these enzymes, inhibition and activation are key regulatory approaches to counter the onset and progression of several cardiovascular impairments. While cardiovascular remedies are already available in excess and of course they are efficacious, a comprehensive description of novel therapeutic enzymes to combat CVDs is the need of the hour. In light of this, the regulation of the functional activity of these enzymes also opens a new avenue for the treatment approaches to be employed. This review describes the importance of non-conventional enzymes as potential candidates in several cardiovascular disorders while highlighting some of the recently targeted therapeutic enzymes in CVDs.

Circulating Lipopolysaccharides and Impaired Antioxidant Status in Patients With Atrial Fibrillation. Data From the ATHERO-AF Study

Objectives: Atrial fibrillation (AF) is characterized by an oxidative imbalance, which is associated with an increased risk of cardiovascular events (CVEs). It is unclear whether low grade endotoxemia may contribute to the impaired antioxidant status in AF patients. We investigated the relationship between circulating lipopolysaccharides (LPS) and antioxidant status in AF patients.

Patients and Methods:Post-hoc analysis from the ongoing prospective observational cohort ATHERO-AF study including 907 patients. Antioxidant status was evaluated by the activity of glutathione peroxidase 3 (GPx3) and superoxide dismutase (SOD). Patients were divided into two groups to evaluate the risk of CVEs: (1) LPS below median and GPx3 above median (n = 254); (2) LPS above median and GPx3 below median (n = 263).

Results: The mean age was 73.5 ± 8.3 years, and 43.1% were women. Median LPS and GPx3 were 50.0 pg/ml [interquartile range (IQR) 15–108] and 20.0 U/ml (IQR 10.0–34.0), respectively. Patients of Groups 2 were older, with a higher prevalence of heart failure. LPS above the median was associated with reduced GPx3 [Odds Ratio for LPS 1.752, 95% Confidence Interval (CI) 1.344–2.285, p < 0.001] and SOD (OR 0.525, 95%CI 0.403–0.683) activity after adjustment for CHA₂DS₂VASc score. In a mean follow-up of 54.0 ± 36.8 months, 118 CVEs occurred, 42 in Group 1 and 76 in Group 2 (Log-Rank test p = 0.001). At multivariable Cox regression analysis, Group 2 was associated with a higher risk of CVEs [Hazard Ratio (HR) 1.644, 95%CI 1.117–2,421, p = 0.012], along with age ≥ 75 years (HR 2.035, 95%CI 1.394–2.972, p < 0.001), diabetes (HR 1.927, 95%CI 1.280–2.900, p = 0.002), and previous cerebrovascular disease (HR 1.895, 95%CI 1.251–2.870, p = 0.003) and previous cardiovascular disease (HR 1.708, 95%CI 1.149–2.538, p = 0.008).

Conclusions: Our study indicates that circulating LPS may contribute to impaired antioxidant status in patients with AF. Patients with coincidentally high LPS and reduced GPx3 activity showed the highest risk of CVEs.

Associations of Antioxidant Enzymes with the Concentration of Fatty Acids in the Blood of Men with Coronary Artery Atherosclerosis

Objective: To identify associations of fatty acids (FAs) with the antioxidant enzymes in the blood of men with coronary atherosclerosis and ischemic heart disease (IHD). Methods: The study included 80 patients: control group—20 men without IHD, the core group—60 men with IHD. The core group was divided into subgroups: subgroup A—with the presence of vulnerable atherosclerotic plaques, subgroup B—with the absence of vulnerable atherosclerotic plaques. We analyzed the levels of FAs, free radicals, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) in the blood. Results. Patients with IHD, compared with the control group: (1) had higher levels of SOD, CAT, myristic, palmitic, palmitoleic, and octadecenoic FAs; (2) had lower levels of GPx, α-linolenic, docosapentaenoic, docosahexaenoic, and arachidonic FAs. In subgroup A there were found: (1) negative associations of SOD—with linoleic, eicosatrienoic, arachidonic, eicosapentaenoic, docosapentaenoic and docosahexaenoic FAs, positive associations—with palmitic acid; (2) positive correlations of CAT level with palmitoleic and stearic acids; (3) negative associations between of GPx and palmitic, palmitoleic, stearic and octadecenoic FAs. Conclusions: Changes in the levels of antioxidant enzymes, and a disbalance of the FAs profile, probably indicate active oxidative processes in the body and may indicate the presence of atherosclerotic changes in the vessels.

Aging-Induced Impairment of Vascular Function: Mitochondrial Redox Contributions and Physiological/Clinical Implications

Significance: The vasculature responds to the respiratory needs of tissue by modulating luminal diameter through smooth muscle constriction or relaxation. Coronary perfusion, diastolic function, and coronary flow reserve are drastically reduced with aging. This loss of blood flow contributes to and exacerbates pathological processes such as angina pectoris, atherosclerosis, and coronary artery and microvascular disease. Recent Advances: Increased attention has recently been given to defining mechanisms behind aging-mediated loss of vascular function and development of therapeutic strategies to restore youthful vascular responsiveness. The ultimate goal aims at providing new avenues for symptom management, reversal of tissue damage, and preventing or delaying of aging-induced vascular damage and dysfunction in the first place. Critical Issues: Our major objective is to describe how aging-associated mitochondrial dysfunction contributes to endothelial and smooth muscle dysfunction via dysregulated reactive oxygen species production, the clinical impact of this phenomenon, and to discuss emerging therapeutic strategies. Pathological changes in regulation of mitochondrial oxidative and nitrosative balance (Section 1) and mitochondrial dynamics of fission/fusion (Section 2) have widespread effects on the mechanisms underlying the ability of the vasculature to relax, leading to hyperconstriction with aging. We will focus on flow-mediated dilation, endothelial hyperpolarizing factors (Sections 3 and 4), and adrenergic receptors (Section 5), as outlined in Figure 1. The clinical implications of these changes on major adverse cardiac events and mortality are described (Section 6). Future Directions: We discuss antioxidative therapeutic strategies currently in development to restore mitochondrial redox homeostasis and subsequently vascular function and evaluate their potential clinical impact (Section 7). Antioxid. Redox Signal. 35, 974-1015.

Evaluation of Oxidative Stress, Apoptosis, and Expression of MicroRNA-208a and MicroRNA-1 in Cardiovascular Patients

BACKGROUND

MicroRNA expression signature and reactive oxygen species (ROS) production have been associated with the development of cardiovascular diseases (CVDs). This study aimed to evaluate oxidative stress, inflammation, apoptosis, and the expression of miRNA-208a and miRNA-1 in cardiovascular patients.

METHODS

The study population included four types of patients (acute coronary syndromes (ACS), myocardial infarction (MI), arrhythmia, and heart failure (HF)), with 10 people in each group, as well as a control group. Quantitative real-time PCR was performed to measure mir-208 and miR-1 expression, the mRNAs of inflammatory mediators (TNFα, iNOS/eNOS), and apoptotic factors (Bax and Bcl2). XOX, MDA, and antioxidant enzymes (CAT, SOD, and GPx) were measured by ZellBio GmbH kits by an ELISA Reader.

RESULTS

The results showed significant decreases in the activity of antioxidant enzymes (CAT, SOD, and Gpx) and a significant increase in the activity of the MDA and XOX in cardiovascular patients. Significant increases in IL-10, iNos, iNOS / eNOS, and TNF-α in cardiovascular patients were also observed. Also, a significant increase in the expression of miR-208 (HF> arrhythmia> ACS> MI) and a significant decrease in the expression of miR-1 (ACS> arrhythmia> HF> MI) were found in all four groups in cardiovascular patients.

CONCLUSION

The results showed increases in oxidative stress, inflammation, apoptotic factors, and in the expression of miR-208a in a variety of cardiovascular patients (ACS, MI, arrhythmia, and HF). It is suggested that future studies determine the relationships that miR-1, miR-208, and oxidative stress indices have with inflammation and apoptosis.

The Effects of Resveratrol on Oxidative Stress Markers: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

OBJECTIVE

Recent trial studies have found that resveratrol supplementation beneficially reduces oxidative stress marker, but, there is no definitive consensus on this context. The present systematic review and meta-analysis aimed to investigate the effect of resveratrol supplementation on oxidative stress parameters.

METHODS

We searched databases of Pubmed, Scopus and Cochrane Library up to December 2018 with no language restriction. Studies were reviewed according to preferred reporting items for systematic reviews and meta-analyses (PRISMA) and Cochrane handbook. To compare the effects of resveratrol with placebo, weighted mean difference (WMD) with 95% confidence intervals (CI) were pooled based on the random-effects model.

RESULTS

Among sixteen clinical trials, we found that resveratrol supplementation increased GPx serum levels significantly (WMD: 18.61; 95% CI: 8.70 to 28.52; P<0.001) but had no significant effect on SOD concentrations (WMD: 1.01; 95% CI: -0.72 to 2.74; P= 0.25), MDA serum levels (WMD: -1.43; 95% CI: -3.46 to 0.61; P = 0.17) and TAC (WMD: -0.09; 95% CI: -0.29 to 0.11; P = 0.36) compared to placebo. Finally, we observed that resveratrol supplementation may not have a clinically significant effect on oxidative stress.

CONCLUSION

However, the number of human trials is limited in this context, and further large prospective clinical trials are needed to confirm the effect of resveratrol supplement on oxidative stress markers.

Effect of antidiabetic drugs on the risk of atrial fibrillation: mechanistic insights from clinical evidence and translational studies

Diabetes mellitus (DM) is an independent risk factor for atrial fibrillation (AF), which is the most common sustained arrhythmia and is associated with substantial morbidity and mortality. Advanced glycation end product and its receptor activation, cardiac energy dysmetabolism, structural and electrical remodeling, and autonomic dysfunction are implicated in AF pathophysiology in diabetic hearts. Antidiabetic drugs have been demonstrated to possess therapeutic potential for AF. However, clinical investigations of AF in patients with DM have been scant and inconclusive. This article provides a comprehensive review of research findings on the association between DM and AF and critically analyzes the effect of different pharmacological classes of antidiabetic drugs on AF.

Connection between the Altered HDL Antioxidant and Anti-Inflammatory Properties and the Risk to Develop Alzheimer's Disease: A Narrative Review

The protein composition of high-density lipoprotein (HDL) is extremely fluid. The quantity and quality of protein constituents drive the multiple biological functions of these lipoproteins, which include the ability to contrast atherogenesis, sustained inflammation, and toxic effects of reactive species. Several diseases where inflammation and oxidative stress participate in the pathogenetic process are characterized by perturbation in the HDL proteome. This change inevitably affects the functionality of the lipoprotein. An enlightening example in this frame comes from the literature on Alzheimer's disease (AD). Growing lines of epidemiological evidence suggest that loss of HDL-associated proteins, such as lipoprotein phospholipase A2 (Lp-PLA2), glutathione peroxidase-3 (GPx-3), and paraoxonase-1 and paraoxonase-3 (PON1, PON3), may be a feature of AD, even at the early stage. Moreover, the decrease in these enzymes with antioxidant/defensive action appears to be accompanied by a parallel increase of prooxidant and proinflammatory mediators, in particular myeloperoxidase (MPO) and serum amyloid A (SAA). This type of derangement of balance between two opposite forces makes HDL dysfunctional, i.e., unable to exert its "natural" vasculoprotective property. In this review, we summarized and critically analyzed the most significant findings linking HDL accessory proteins and AD. We also discuss the most convincing hypothesis explaining the mechanism by which an observed systemic occurrence may have repercussions in the brain.

Xenopus gpx3 Mediates Posterior Development by Regulating Cell Death during Embryogenesis

Glutathione peroxidase 3 (GPx3) belongs to the glutathione peroxidase family of selenoproteins and is a key antioxidant enzyme in multicellular organisms against oxidative damage. Downregulation of GPx3 affects tumor progression and metastasis and is associated with liver and heart disease. However, the physiological significance of GPx3 in vertebrate embryonic development remains poorly understood. The current study aimed to investigate the functional roles of gpx3 during embryogenesis. To this end, we determined gpx3's spatiotemporal expression using Xenopus laevis as a model organism. Using reverse transcription polymerase chain reaction (RT-PCR), we demonstrated the zygotic nature of this gene. Interestingly, the expression of gpx3 enhanced during the tailbud stage of development, and whole mount in situ hybridization (WISH) analysis revealed gpx3 localization in prospective tail region of developing embryo. gpx3 knockdown using antisense morpholino oligonucleotides (MOs) resulted in short post-anal tails, and these malformed tails were significantly rescued by glutathione peroxidase mimic ebselen. The gene expression analysis indicated that gpx3 knockdown significantly altered the expression of genes associated with Wnt, Notch, and bone morphogenetic protein (BMP) signaling pathways involved in tailbud development. Moreover, RNA sequencing identified that gpx3 plays a role in regulation of cell death in the developing embryo. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and phospho-histone 3 (PH3) staining confirmed the association of gpx3 knockdown with increased cell death and decreased cell proliferation in tail region of developing embryos, establishing the involvement of gpx3 in tailbud development by regulating the cell death. Furthermore, these findings are inter-related with increased reactive oxygen species (ROS) levels in gpx3 knockdown embryos, as measured by using a redox-sensitive fluorescent probe HyPer. Taken together, our results suggest that gpx3 plays a critical role in posterior embryonic development by regulating cell death and proliferation during vertebrate embryogenesis.

Unraveling the Antioxidant, Binding and Health-Protecting Properties of Phenolic Compounds of Beers with Main Human Serum Proteins: In Vitro and In Silico Approaches

Our recently published in vivo studies and growing evidence suggest that moderate consumption of beer possesses several health benefits, including antioxidant and cardiovascular effects. Although beer contains phenolic acids and flavonoids as the major composition, and upon consumption, the levels of major components increase in the blood, there is no report on how these beer components interact with main human serum proteins. Thus, to address the interaction potential between beer components and human serum proteins, the present study primarily aims to investigate the components of beer from different industrial sources as well as their mode of interaction through in silico analysis. The contents of the bioactive compounds, antioxidant capacities and their influence on binding properties of the main serum proteins in human metabolism (human serum albumin (HSA), plasma circulation fibrinogen (PCF), C-reactive protein (CRP) and glutathione peroxidase 3 (GPX3)) were studied. In vitro and in silico studies indicated that phenolic substances presented in beer interact with the key regions of the proteins to enhance their antioxidant and health properties. We hypothesize that moderate consumption of beer could be beneficial for patients suffering from coronary artery disease (CAD) and other health advantages by regulating the serum proteins.

Association between glutathione peroxidase-3 activity and carotid atherosclerosis in patients with type 2 diabetes mellitus

BACKGROUND AND AIMS

Deficiency of glutathione peroxidase 3 (GPx3) has been recognized as an independent risk factor for cardiovascular events. However, little is known regarding the role of GPx3 in carotid atherosclerosis, which is ubiquitously observed in type 2 diabetes mellitus (T2DM). This study aimed to investigate the relationship between GPx3 activity and carotid atherosclerosis among patients with T2DM.

METHODS

From January 2018 to December 2018, 245 consecutive patients with T2DM were enrolled in this observational study. Assessment of serum GPx3 activity was performed after admission. We also used carotid ultrasound to measure the mean carotid intima-media thickness (CIMT) and to assess the presence of carotid plaque.

RESULTS

Of the 245 patients, the median serum GPx3 activity was 22.5 U/ml (interquartile range, 12.4-35.9 U/ml). Carotid plaque was observed in 113 (46.1%) patients, and mean CIMT was 0.8 ± 0.1 mm. Univariate analysis showed that age, smoking, previous coronary heart disease, carotid plaque, and level of mean CIMT and hypersensitive C-reactive protein were significantly associated with decreasing tertile of GPx3. Furthermore, after adjusting for all potential confounders by multivariable logistic regression analysis, PGx3 activity was significantly and independently associated with the mean CIMT (β = -.406, p = .002) and carotid plaque (first tertile of GPx3, odds ratio, 1.870, 95% confidence intervals, 1.124-3.669, p = .024).

CONCLUSIONS

This study demonstrated that serum GPx3 activity was inversely associated with mean CIMT and carotid plaque, suggesting that lower GPx3 activity may be an independent predictor for carotid atherosclerosis in T2DM.

Selenoprotein Gpx3 knockdown induces myocardial damage through Ca2+ leaks in chickens

Glutathione peroxidase 3 (Gpx3) is a pivotal selenoprotein that acts as an antioxidant. However, the role of Gpx3 in maintaining the normal metabolism of cardiomyocytes remains to be elucidated in more detail. Herein, we employed a model of Gpx3 interference in chicken embryos in vivo and Gpx3 knockdown chicken cardiomyocytes in vitro. Real-time PCR, western blotting and fluorescent staining were performed to detect reactive oxygen species (ROS), the calcium (Ca²⁺) concentration, endoplasmic reticulum (ER) stress, myocardial contraction, inflammation and heat shock proteins (HSPs). Our results revealed that Gpx3 suppression increased the level of ROS, which induced Ca²⁺ leakage in the cytoplasm by blocking the expression of Ca²⁺ channels. The imbalance of Ca²⁺ homeostasis triggered ER stress and blocked myocardial contraction. Furthermore, we found that Ca²⁺ imbalance in the cytoplasm induced severe inflammation, and HSPs might play a protective role throughout these processes. In conclusion, Gpx3 suppression induces myocardial damage through the activation of Ca²⁺-dependent ER stress.

Extracellular Glutathione Peroxidase GPx3 and Its Role in Cancer

Mammalian cells possess a multifaceted antioxidant enzyme system, which includes superoxide dismutases, catalase, the peroxiredoxin/thioredoxin and the glutathione peroxidase systems. The dichotomous role of reactive oxygen species and antioxidant enzymes in tumorigenesis and cancer progression complicates the use of small molecule antioxidants, pro-oxidants, and targeting of antioxidant enzymes as therapeutic approaches for cancer treatment. It also highlights the need for additional studies to investigate the role and regulation of these antioxidant enzymes in cancer. The focus of this review is on glutathione peroxidase 3 (GPx3), a selenoprotein, and the only extracellular GPx of a family of oxidoreductases that catalyze the detoxification of hydro- and soluble lipid hydroperoxides by reduced glutathione. In addition to summarizing the biochemical function, regulation, and disease associations of GPx3, we specifically discuss the role and regulation of systemic and tumor cell expressed GPx3 in cancer. From this it is evident that GPx3 has a dichotomous role in different tumor types, acting as both a tumor suppressor and pro-survival protein. Further studies are needed to examine how loss or gain of GPx3 specifically affects oxidant scavenging and redox signaling in the extracellular tumor microenvironment, and how GPx3 might be targeted for therapeutic intervention.

Plasma exosomes characterization reveals a perioperative protein signature in older patients undergoing different types of on-pump cardiac surgery

Although exosomes are extracellular nanovesicles mainly involved in cardioprotection, it is not known whether plasma exosomes of older patients undergoing different types of on-pump cardiac surgery protect cardiomyocytes from apoptosis. Since different exosomal proteins confer pro-survival effects, we have analyzed the protein cargo of exosomes circulating early after aortic unclamping. Plasma exosomes and serum cardiac troponin I levels were measured in older cardiac surgery patients (NYHA II-III) who underwent first-time on-pump coronary artery bypass graft (CABG; n = 15) or minimally invasive heart valve surgery (mitral valve repair, n = 15; aortic valve replacement, n = 15) at induction of anesthesia (T0, baseline), 3 h (T1) and 72 h (T2) after aortic unclamping. Anti-apoptotic role of exosomes was assessed in HL-1 cardiomyocytes exposed to hypoxia/re-oxygenation (H/R) by TUNEL assay. Protein exosomal cargo was characterized by mass spectrometry approach. Exosome levels increased at T1 (P < 0.01) in accord with troponin values in all groups. In CABG group, plasma exosomes further increased at T2 (P < 0.01) whereas troponin levels decreased. In vitro, all T1-exosomes prevented H/R-induced apoptosis. A total of 340 exosomal proteins were identified in all groups, yet 10% of those proteins were unique for each surgery type. In particular, 22 and 12 pro-survival proteins were detected in T1-exosomes of heart valve surgery and CABG patients, respectively. Our results suggest that endogenous intraoperative cardioprotection in older cardiac surgery patients is early mediated by distinct exosomal proteins regardless of surgery type.

Therapeutic approaches to diabetic cardiomyopathy: Targeting the antioxidant pathway

The global epidemic of cardiovascular disease continues unabated and remains the leading cause of death both in the US and worldwide. We hereby summarize the available therapies for diabetes and cardiovascular disease in diabetics. Clearly, the current approaches to diabetic heart disease often target the manifestations and certain mediators but not the specific pathways leading to myocardial injury, remodeling and dysfunction. Better understanding of the molecular events determining the evolution of diabetic cardiomyopathy will provide insight into the development of specific and targeted therapies. Recent studies largely increased our understanding of the role of enhanced inflammatory response, ROS production, as well as the contribution of Cyp-P450-epoxygenase-derived epoxyeicosatrienoic acid (EET), Peroxisome Proliferator-Activated Receptor Gamma Coactivator-1α (PGC-1α), Heme Oxygenase (HO)-1 and 20-HETE in pathophysiology and therapy of cardiovascular disease. PGC-1α increases production of the HO-1 which has a major role in protecting the heart against oxidative stress, microcirculation and mitochondrial dysfunction. This review describes the potential drugs and their downstream targets, PGC-1α and HO-1, as major loci for developing therapeutic approaches beside diet and lifestyle modification for the treatment and prevention of heart disease associated with obesity and diabetes.

Ribose-cysteine protects against the development of atherosclerosis in apoE-deficient mice

Ribose-cysteine is a synthetic compound designed to increase glutathione (GSH) synthesis. Low levels of GSH and the GSH-dependent enzyme, glutathione peroxidase (GPx), is associated with cardiovascular disease (CVD) in both mice and humans. Here we investigate the effect of ribose-cysteine on GSH, GPx, oxidised lipids and atherosclerosis development in apolipoprotein E-deficient (apoE-/-) mice. Female 12-week old apoE-/- mice (n = 15) were treated with 4-5 mg/day ribose-cysteine in drinking water for 8 weeks or left untreated. Blood and livers were assessed for GSH, GPx activity and 8-isoprostanes. Plasma alanine transferase (ALT) and lipid levels were measured. Aortae were quantified for atherosclerotic lesion area in the aortic sinus and brachiocephalic arch and 8-isoprostanes measured. Ribose-cysteine treatment significantly reduced ALT levels (p<0.0005) in the apoE-/- mice. Treatment promoted a significant increase in GSH concentrations in the liver (p<0.05) and significantly increased GPx activity in the liver and erythrocytes of apoE-/-mice (p<0.005). The level of 8-isoprostanes were significantly reduced in the livers and arteries of apoE-/- mice (p<0.05 and p<0.0005, respectively). Ribose-cysteine treatment showed a significant decrease in total and low density lipoprotein (LDL) cholesterol (p<0.05) with no effect on other plasma lipids with the LDL reduction likely through upregulation of scavenger receptor-B1 (SR-B1). Ribose-cysteine treatment significantly reduced atherosclerotic lesion area by >50% in both the aortic sinus and brachiocephalic branch (p<0.05). Ribose-cysteine promotes a significant GSH-based antioxidant effect in multiple tissues as well as an LDL-lowering response. These effects are accompanied by a marked reduction in atherosclerosis suggesting that ribose-cysteine might increase protection against CVD.

Progress in the emerging role of selenoproteins in cardiovascular disease: focus on endoplasmic reticulum-resident selenoproteins

Cardiovascular diseases represent one of the most important health problems of developed countries. One of the main actors involved in the onset and development of cardiovascular diseases is the increased production of reactive oxygen species that, through lipid peroxidation, protein oxidation and DNA damage, induce oxidative stress and cell death. Basic and clinical research are ongoing to better understand the endogenous antioxidant mechanisms that counteract oxidative stress, which may allow to identify a possible therapeutic targeting/application in the field of stress-dependent cardiovascular pathologies. In this context, increasing attention is paid to the glutathione/glutathione-peroxidase and to the thioredoxin/thioredoxin-reductase systems, among the most potent endogenous antioxidative systems. These key enzymes, belonging to the selenoprotein family, have a well-established function in the regulation of the oxidative cell balance. The aim of the present review was to highlight the role of selenoproteins in cardiovascular diseases, introducing the emerging cardioprotective role of endoplasmic reticulum-resident members and in particular one of them, namely selenoprotein T or SELENOT. Accumulating evidence indicates that the dysfunction of different selenoproteins is involved in the susceptibility to oxidative stress and its associated cardiovascular alterations, such as congestive heart failure, coronary diseases, impaired cardiac structure and function. Some of them are under investigation as useful pathological biomarkers. In addition, SELENOT exhibited intriguing cardioprotective effects by reducing the cardiac ischemic damage, in terms of infarct size and performance. In conclusion, selenoproteins could represent valuable targets to treat and diagnose cardiovascular diseases secondary to oxidative stress, opening a new avenue in the field of related therapeutic strategies.

Selenoprotein-P Deficiency Predicts Cardiovascular Disease and Death

Selenoprotein-P (SELENOP) is the main carrier of selenium to target organs and reduces tissue oxidative stress both directly and by delivering selenium to protective selenoproteins. We tested if the plasma concentration of SELENOP predicts cardiovascular morbidity and mortality in the primary preventive setting. SELENOP was measured from the baseline exam in 2002–2006 of the Malmö Preventive Project, a population-based prospective cohort study, using a validated ELISA. Quintiles of SELENOP concentration were related to the risk of all-cause mortality, cardiovascular mortality, and a first cardiovascular event in 4366 subjects during a median (interquartile range) follow-up time of 9.3 (8.3–11) years using Cox proportional Hazards Model adjusting for cardiovascular risk factors. Compared to subjects in the lowest quintile of SELENOP, the risk of all three endpoints was significantly lower in quintiles 2–5. The risk (multivariate adjusted hazard ratio, 95% CI) decreased gradually with the lowest risk in quintile 4 for all-cause mortality (0.57, 0.48–0.69) (p < 0.001), cardiovascular mortality (0.52, 0.37–0.72) (p < 0.001), and first cardiovascular event (0.56, 0.44–0.71) (p < 0.001). The lower risk of a first cardiovascular event in quintiles 2–5 as compared to quintile 1 was significant for both coronary artery disease and stroke. We conclude that the 20% with lowest SELENOP concentrations in a North European population without history of cardiovascular disease have markedly increased risk of cardiovascular morbidity and mortality, and preventive selenium supplementation studies stratified for these subjects are warranted.

Age associated non-linear regulation of redox homeostasis in the anucleate platelet: Implications for CVD risk patients

Background

Aging is a complex physiological phenomenon, intricately associated with cardiovascular pathologies, where platelets play a central pathophysiological role. Although antiplatelets are commonly employed to prevent and treat major adverse cardiovascular events, aging associated intraplatelet changes remain largely unexplored.

Methods

Platelets were studied in high cardiovascular risk patients (aged 40–100 years) comparing them to younger healthy subjects. This was followed by cross sectional and longitudinal mice studies. Flow cytometry, biochemical and molecular assays were used to study platelets comprehensively.

Findings

CVD Patients were categorized in the age groups 40–59, 60–79, and 80–100 years. Progressive decline in platelet health was observed in the 40–79 years age cohort, marked by increase in oxidative stress, hyperactivation and apoptotic markers. Paradoxically, this was reversed in patients aged above 79 years and the improved platelet phenotype was associated with lower oxidative damage. The platelets from the very old (80–100 year) group were found to be preloaded with increased antioxidants, which also contributed to higher resistance against induced redox insults. Cross sectional mouse studies excluded the effect of comorbidities and medications. Longitudinal mouse studies implicate an adaptive increase in antioxidant levels as the mechanism.

Interpretation

We report a novel age associated, non-linear redox regulation in platelets in both humans and mice. In advanced age, there occurs an adaptive increase in platelet antioxidants, reducing the intracellular ROS and leading to a healthier platelet phenotype. Clinically, our results advocate the use of less aggressive antiplatelet therapies for CVD in the elderly population.

Fund

Study funded by NIH-NHLBI, RO1-HL122815 and RO1-HL115247.

Effect of Gpx3 gene silencing by siRNA on apoptosis and autophagy in chicken cardiomyocytes

Glutathione peroxidase 3 (Gpx3), as an important selenoprotein, is the most crucial antioxidant defense in cardiomyocytes. However, the role of Gpx3 in Se-deficient cardiomyocyte damage still less reported. Here, we developed Gpx3 silence cardiomyocytes culture model (small interfering RNA; siRNA) for research the crosstalk between autophagy and apoptosis. Quantitative real-time PCR and western blot analysis are performed to detect the expression of apoptosis and autophagy-related genes. MDC stain, flow cytometry, AO/EB stain, and electron microscope were performed to observe the changes of cell morphology. Our results reveal that Gpx3 suppression can significant increases in ROS (p < 0.05) levels, which further induced apoptosis through upregulated the expression of Caspase-3 in cardiomyocytes. Meanwhile, we also found that the whole process is accompanied by the occurrence of autophagy, which are promoted by inhibiting the mTOR, and increasing the expression of ATG-7, ATG-10, and ATG-12. Altogether, we conclude that the apoptotic and autophagic response machineries share antagonistic function in Gpx3 knockdown cardiomyocytes.

Oxidative Stress and Effect of Treatment on the Oxidation Product Decomposition Processes in IBD

Oxidative stress plays an important role in IBD because chronic intestinal inflammation is associated with the overproduction of reactive oxygen species (ROS) leading to oxidative stress, which has been implicated in IBD. Many lines of evidence suggest that IBD is associated with an imbalance between ROS and antioxidant activity which generates oxidative stress as the result of either ROS overproduction or a decrease in antioxidant activity. Our study was to evaluate the influence of oxidative stress and antioxidants on the course of the disease and treatment of IBD patients. Our results show that an increase of LOOH levels positively correlates with an increase in MDA levels; therefore, MDA may be a marker indicating lipid peroxidation. Also, being the decomposition product of oxidation processes, MDA may be applied as a useful biomarker for identifying the effect of endogenous oxidative stress in Crohn's disease patients. The anti-inflammatory efficacy of AZA drugs may be the result of a reduction of the amount of lipid peroxides in the intestinal mucosa cells in CD patients and facilitate mucosal healing.

Tumor suppressor NPRL2 induces ROS production and DNA damage response

The SEA/GATOR complex is an essential regulator of the mTORC1 pathway. In mammals the GATOR1 complex is composed of the proteins DEPDC5, NPRL2 and NPRL3. GATOR1 serves as an mTORC1 inhibitor and activates the mTORC1-modulating RagA GTPase. However, several GATOR members have mTORC1 independent functions. Here we characterize mammalian cells overexpressing the GATOR1 component NPRL2. We demonstrate that, in the cells with active p53, ectopic expression of NPRL2 induces NOX2-dependent production of reactive oxygen species and DNA damage. Overexpressed NPRL2 accumulates in the nucleus, together with apoptosis-inducing factor (AIF). These events are accompanied by phosphorylation of p53, activation of a DNA-damage response and cell cycle arrest in G1 phase, followed by apoptosis. In the cells negative for active p53, NPRL2 ectopic expression leads to activation of CHK1 or CHK2 kinases and cell cycle arrest in S or G2/M phases. Combined, these results demonstrate a new role for the NPRL2, distinct from its function in mTORC1 regulation.

Atherothrombosis and Oxidative Stress: Mechanisms and Management in Elderly

SIGNIFICANCE

The incidence of cardiovascular events (CVEs) increases with age, representing the main cause of death in an elderly population. Aging is associated with overproduction of reactive oxygen species (ROS), which may affect clotting and platelet activation, and impair endothelial function, thus predisposing elderly patients to thrombotic complications. Recent Advances: There is increasing evidence to suggest that aging is associated with an imbalance between oxidative stress and antioxidant status. Thus, upregulation of ROS-producing enzymes such as nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and myeloperoxidase, along with downregulation of antioxidant enzymes, such as superoxide dismutase and glutathione peroxidase, occurs during aging. This imbalance may predispose to thrombosis by enhancing platelet and clotting activation and eliciting endothelial dysfunction. Recently, gut-derived products, such as trimethylamine N-oxide (TMAO) and lipopolysaccharide, are emerging as novel atherosclerotic risk factors, and gut microbiota composition has been shown to change by aging, and may concur with the increased cardiovascular risk in the elderly.

CRITICAL ISSUES

Antioxidant treatment is ineffective in patients at risk or with cardiovascular disease. Further, anti-thrombotic treatment seems to work less in the elderly population.

FUTURE DIRECTIONS

Interventional trials with antioxidants targeting enzymes implicated in aging-related atherothrombosis are warranted to explore whether modulation of redox status is effective in lowering CVEs in the elderly. Antioxid. Redox Signal. 27, 1083-1124.

Dietary Polyphenol Intake, but Not the Dietary Total Antioxidant Capacity, Is Inversely Related to Cardiovascular Disease in Postmenopausal Polish Women: Results of WOBASZ and WOBASZ II Studies

The aim of the study was to assess the relationship between the dietary polyphenol intake (DPI) and the dietary total antioxidant capacity (DTAC) and the prevalence of cardiovascular disease (CVD) in postmenopausal women. Participants were 916 postmenopausal women diagnosed with CVD and 1683 postmenopausal women without history of CVD, who took part in the population-based studies carried out in Poland: WOBASZ (2003–2005) and WOBASZ II (2013-2014). Nutritional data were collected using a single 24-hour dietary recall. DPI and DTAC in the CVD women were significantly lower and accounted for 1766.39 mg/d and 10.84 mmol/d, respectively, versus 1920.57 mg/d and 11.85 mmol/d in the women without CVD, but these differences disappeared after the standardization for energy input. Also, in the multiple-adjustment model, higher DPI, but not DTAC, was associated with the reduced odds ratio for the prevalence of CVD. Beverages, mainly coffee and tea, contributed in more than 40% to DPI and in more than a half to DTAC. In this study, higher dietary polyphenol intake, but not the dietary total antioxidant capacity, was inversely associated with CVD in postmenopausal women, which points to the health benefits of increased polyphenol intake from food sources for these women.

Cardiac oxidative stress in diabetes: Mechanisms and therapeutic potential

Macrovascular complications of diabetes, including diabetic cardiovascular disease (CVD), occur through a number of hyperglycaemia-induced mechanisms that include generation of oxidative stress, accumulation of advanced glycation end-products (AGE) and activation of protein kinase C (PKC). Cardiac oxidative stress is associated with increased cardiac fibrosis and hypertrophy, and reduced cardiac performance and contractility, leading to severe cardiac dysfunction and potentially fatal cardiac events. It occurs under conditions of excessive synthesis of reactive oxygen species (ROS). The ensuing activation of transcription factors such as nuclear factor-κB produces inflammation, fibrosis, hypertrophy and further oxidative stress, which itself causes DNA and membrane damage. This review summarises the mechanisms that generate ROS in the diabetic heart: mitochondrial electron leakage, activity of ROS-generating enzymes such as NADPH oxidase, xanthine oxidase and 12/15 lipoxygenase, uncoupling of nitric oxide synthase, accumulation of AGEs and activation of PKC. There is interaction between many of these ROS-generating pathways, with data from a range of published studies indicating that a common upstream pathway is the interaction of AGEs with their receptor (RAGE), which further promotes ROS synthesis. Therefore, agents targeted at decreasing ROS production have been investigated for prevention or treatment of diabetic CVD through reducing oxidative stress, and this review considers some of the studies carried out with anti-oxidant therapies and the feasibility of this approach for protecting against diabetic cardiomyopathy.

Is There an Interplay Between Adherence to Mediterranean Diet, Antioxidant Status, and Vascular Disease in Atrial Fibrillation Patients?

Mediterranean Diet (Med-Diet) is associated with reduced incidence of vascular events (VEs) in atrial fibrillation (AF), but the mechanism accounting for its beneficial effect is only partially known. We hypothesized that Med-Diet may reduce VEs by improving antioxidant status, as assessed by glutathione peroxidase 3 (GPx3) and superoxide dismutase (SOD). We performed a prospective cohort study investigating the relationship between adherence to Med-Diet, serum baseline GPx3 and SOD activities, and the occurrence of VEs in 690 AF patients. GPx3 activity was directly associated with Med-Diet score (B = 0.192, p < 0.001) and inversely with age (B = -0.124, p = 0.001), after adjustment for potential confounders; Med-Diet weakly affected SOD levels. During a mean follow-up of 46.1 ± 28.2 months, 89 VEs were recorded; patients with VEs had lower GPx3 levels compared with those without VEs (p = 0.002); and no differences regarding SOD activity were found. Multivariable Cox regression analysis showed that age (Hazard ratio [HR]:1.065, p < 0.001), logGPx3 (above median, HR: 0.629, p < 0.05), and Med-Diet score (HR: 0.547, p < 0.05) predicted VEs. Med-Diet favorably modulates antioxidant activity of GPx3 in AF, resulting in reduced VEs rate. We hypothesize that the modulation of GPx3 levels by Med-Diet could represent an additional nutritional strategy to prevent VEs in AF patients. Antioxid. Redox Signal. 25, 751-755.